工学学士, 中国南京航空学院

Bachelor of Engineering, Nanjing University of Aeronautics and Astronautics

工学修士, 電気通信大学

Master of Engineering, The University of Electro-Communications

博士（工学）, 電気通信大学

Doctor of Engineering, The University of Electro-Communications

Electric circuits

Communication theory

signal processing

Numerical computation

image processing

電子回路

通信理論

信号処理

数値計算

画像処理

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Measurement engineering

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Communication and network engineering

Informatics, Intelligent informatics

Informatics, Database science

Informatics, Information theory

01 Apr. 2019 - 31 Mar. 2020
コニカミノルタ株式会社, 情報機器開発本部 開発イノベーションセンター 開発企画部, マネージャー

01 Oct. 2014 - 31 Mar. 2020
Tokyo Metropolitan University, 電子工学科, 非常勤講師

01 May 2011
The University of Electro-Communications, 情報・ネットワーク工学専攻, Professor

01 Apr. 2010 - 30 Apr. 2011
The University of Electro-Communications, 情報・通信工学専攻, Associate Professor

01 Apr. 2007 - 31 Mar. 2010
The University of Electro-Communications, 情報通信工学科, Associate Professor

01 Apr. 2004 - 31 Mar. 2007
The University of Electro-Communications, 情報通信工学科, Associate Professor

01 Apr. 1996 - 31 Mar. 2004
Nagaoka University of Technology, 電気系, Associate Professor

01 Apr. 1993 - 31 Mar. 1996
The University of Electro-Communications, 電子情報工学科, Assistant Professor

01 Aug. 1984 - 30 Sep. 1987
Nanjing University of Aeronautics and Astronautics, 電子工程系, Assistant Professor

Mar. 1993
The University of Electro-Communications, Graduate School, Division of Electro Communications, Department of Communication and System Engineering

Sep. 1980 - Jul. 1984
Nanjing University of Aeronautics and Astronautics, Faculty of Engineering, Department of Electrical Engineering, China

Apr. 2004 - May 2010
電子情報通信学会回路とシステム研究専門委員会委員, 電子情報通信学会, Society

May 2010
シニア会員, 電子情報通信学会, Society

Jan. 2001
Senior Member, The Institute of Electric and Electronics Engineers, Society

Nov. 2011
電子情報通信学会信号処理研究専門委員会
SIP学生奨励賞

Mar. 2008
電子情報通信学会回路とシステム研究専門委員会
優秀学生発表賞

May 2002
The challenge prize of 4th LSI IP Design Award

Dec. 1987
China
The third prize of the Science and Technology Progress Award of China
China

Image Adjustment for Multi-exposure Images Based on Convolutional Neural Networks
I. Funahashi; T. Yoshida; X. Zhang; M. Iwahashi
IEICE Trans. Information and Systems, IEICE, E105-D, 1, 123-133, 01 Jan. 2022, Peer-reviwed
Scientific journal, English

Design of two channel biorthogonal graph wavelet filter banks with half-band kernels
Xi Zhang
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Institute of Electronics, Information and Communication, Engineers, IEICE, E100A, 9, 1743-1750, 01 Sep. 2017, Peer-reviwed, In this paper, we propose a novel design method of two channel critically sampled compactly supported biorthogonal graph wavelet filter banks with half-band kernels. First of all, we use the polynomial half-band kernels to construct a class of biorthogonal graph wavelet filter banks, which exactly satisfy the PR (perfect reconstruction) condition. We then present a design method of the polynomial half-band kernels with the specified degree of flatness. The proposed design method utilizes the PBP (Parametric Bernstein Polynomial), which ensures that the half-band kernels have the specified zeros at = 2. Therefore the constraints of flatness are satisfied at both of = 0 and = 2, and then the resulting graph wavelet filters have the flat spectral responses in passband and stopband. Furthermore, we apply the Remez exchange algorithm to minimize the spectral error of lowpass (highpass) filter in the band of interest by using the remaining degree of freedom. Finally, several examples are designed to demonstrate the effectiveness of the proposed design method.
Scientific journal, English

High Dynamic Range Image Compression with Improved Logarithmic Transformation
M. Sumizawa; X. Zhang
IEICE Communications Express, IEICE, 6, 1, 17-21, 01 Jan. 2017, Peer-reviwed,

High dynamic range (HDR) images have been developed to have almost the same dynamic range as human eye, but the huge amount of data brings a problem in storage and transmission. To compress HDR images, an efficient coding method using logarithmic transformation had been proposed in [4]. In this letter, we improve the logarithmic transformation and then derive the optimal parameter to minimize the coding error in HDR region. It is experimentally confirmed that the improved coding method has less coding error in HDR region than other existing methods.

Scientific journal, English

A New Class of Hilbert Pairs of Almost Symmetric Orthogonal Wavelet Bases
Daiwei Wang; Xi Zhang
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E99A, 5, 884-891, May 2016, Peer-reviwed, This paper proposes a new class of Hilbert pairs of almost symmetric orthogonal wavelet bases. For two wavelet bases to form a Hilbert pair, the corresponding scaling lowpass filters are required to satisfy the half-sample delay condition. In this paper, we design simultaneously two scaling lowpass filters with the arbitrarily specified flat group delay responses at omega = 0, which satisfy the half-sample delay condition. In addition to specifying the number of vanishing moments, we apply the Remez exchange algorithm to minimize the difference of frequency responses between two scaling lowpass filters, in order to improve the analyticity of complex wavelets. The equiripple behavior of the error function can be obtained through a few iterations. Therefore, the resulting complex wavelets are orthogonal and almost symmetric, and have the improved analyticity. Finally, some examples are presented to demonstrate the effectiveness of the proposed design method.
Scientific journal, English

A NOVEL DESIGN OF BIORTHOGONAL GRAPH WAVELET FILTER BANKS
Xi Zhang
2016 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP), IEEE, 1134, 1529-1533, 2016, Peer-reviwed, This paper proposes a novel method for designing compactly supported biorthogonal graph wavelet filter banks with flat spectral responses. We firstly construct a class of biorthogonal graph filter banks by using the polynomial half-band kernels, and then present a design method for the polynomial half-band kernel. The proposed design method utilizes the PBP (Parametric Bernstein Polynomial), which ensures that the half-band kernel has the specified zeros at A = 2, that is, the flatness constraints both in passband and stopband. Therefore, the resulting graph filters have the flat spectral responses. Furthermore, we apply the Remez exchange algorithm to minimize the spectral error by using the remaining degree of freedom. Finally, two design examples are given to demonstrate the effectiveness of the design method proposed in this paper.
International conference proceedings, English

Design of Orthogonal Graph Wavelet Filter Banks
Xi Zhang
PROCEEDINGS OF THE IECON 2016 - 42ND ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, IEEE, FD-004898, 889-894, 2016, Peer-reviwed, This paper proposes a novel design method of two channel compactly supported near orthogonal graph wavelet filter banks. We firstly prove the necessary condition for the orthogonality of filter banks where the kernel filter must have a flat spectral in passband if having flat stopband, and then derive the closed-form solution for the maximally flat filters. We also give a filter function that ensures the specified degrees of flatness at lambda = 0 and lambda = 2 by the maximally flat filters. Therefore, we can use the remaining coefficients to minimize the reconstruction error of filter banks, where the optimization tool in Matlab is used to design the filter banks without any initial solution. Some examples are designed by using the proposed method and the spectral are compared with the conventional design methods. It is shown from the experimental results that the graph filter banks proposed in this paper outperform the conventional kernel filters. Finally, the proposed graph wavelets are applied to the Minnesota traffic graph to demonstrate the effectiveness of the proposed design method.
International conference proceedings, English

Closed-form design of maxflat R-regular FIR Mth-band filters with arbitrary group delay using waveform moments
Xi Zhang; Daisuke Kobayashi; Tatsuya Wada; Toshinori Yoshikawa; Yoshinori Takei
European Signal Processing Conference, European Signal Processing Conference, EUSIPCO, 06-10-, 129-132, 03 Apr. 2015, Mth-band filters have been found numerous applications in multirate signal processing systems, filter banks and wavelets. In this paper, a new closed-form expression is presented for the impulse response of the maxflat R-regular FIR Mth-band filters with arbitrary group delay. The filter coefficients are directly obtained by solving a linear system of Vandermonde equations that are derived from the regularity conditions via waveform moments. Moreover, the group delay of the proposed FIR Mth-band filters can be arbitrarily specified. Finally, some design examples are presented to demonstrate the effectiveness of the proposed maxflat R-regular FIR Mth-band filters.
International conference proceedings, English

VARIABLE STEP-SIZE BASED-ADAPTIVE ALGORITHM FOR ACOUSTIC FEEDBACK CANCELLATION DURING ONLINE OPERATION OF ANC SYSTEMS
Shakeel Ahmed; Muhammad Tahir Akhtar; Xi Zhang
2015 IEEE CHINA SUMMIT & INTERNATIONAL CONFERENCE ON SIGNAL AND INFORMATION PROCESSING, IEEE, 6413, 74-78, 2015, Peer-reviwed, In active noise control (ANC) system, the injection of white Gaussian noise (WGN) for online feedback path modeling and neutralization (FBPMN) degrades the noise-reduction-performance (NRP). In this paper: (1) a tuning free gain scheduling of WGN is used to improve the NRP of ANC system, and (2) a variable step-size is used to compensate for the decrease in the convergence of FBPMN filter due to gain scheduling. The computer simulations are carried out to demonstrate the performance of the proposed method.
International conference proceedings, English

Design of Mth-band FIR Linear Phase Filters
X. Zhang
Proc. of The 2014 19th International Conference on Digital Signal Processing (DSP 2014), TP2D-3, 21 Aug. 2014, Peer-reviwed
International conference proceedings, English

Lossy to lossless image coding based on wavelets using a complex allpass filter
Xi Zhang; Noriaki Fukuda
INTERNATIONAL JOURNAL OF WAVELETS MULTIRESOLUTION AND INFORMATION PROCESSING, WORLD SCIENTIFIC PUBL CO PTE LTD, 12, 4, 1-16, Jul. 2014, Peer-reviwed, Wavelet-based image coding has been adopted in the international standard JPEG 2000 for its efficiency. It is well-known that the orthogonality and symmetry of wavelets are two important properties for many applications of signal processing and image processing. Both can be simultaneously realized by the wavelet filter banks composed of a complex allpass filter, thus, it is expected to get a better coding performance than the conventional biorthogonal wavelets. This paper proposes an effective implementation of orthonormal symmetric wavelet filter banks composed of a complex allpass filter for lossy to lossless image compression. First, irreversible real-to-real wavelet transforms are realized by implementing a complex allpass filter for lossy image coding. Next, reversible integer-to-integer wavelet transforms are proposed by incorporating the rounding operation into the filtering processing to obtain an invertible complex allpass filter for lossless image coding. Finally, the coding performance of the proposed orthonormal symmetric wavelets is evaluated and compared with the D-9/7 and D-5/3 biorthogonal wavelets. It is shown from the experimental results that the proposed allpass-based orthonormal symmetric wavelets can achieve a better coding performance than the conventional D-9/7 and D-5/3 biorthogonal wavelets both in lossy and lossless coding.
Scientific journal, English

SCALABLE VIDEO CODING USING ALLPASS-BASED WAVELET FILTERS
Xi Zhang; Takuya Suzuki
2014 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS), IEEE, B1L-B-1, 264-267, 2014, Peer-reviwed, Scalable video coding (SVC) allows to encode videos in a unique bit stream at several operating points corresponding to different quality, spatial resolution and temporal frame rate. In this paper, we apply the allpass-based wavelet filters to wavelet-based scalable video coding (WSVC) for improving the coding performance, in particular, at reduced spatial resolutions. The allpass-based wavelet filters used in this paper are orthogonal and symmetric, and have a better frequency response than the D-5/3 and D-9/7 biorthogonal wavelet filters. Therefore, some spatial aliasing effects can be suppressed, when the allpass-based wavelet filters are used as a spatial transform in WSVC. Moreover, the inverse MCTF transform is performed at full spatial resolution to avoid the imprecision of the deduced MVs. Finally, a coding performance comparison between the proposed allpass-based and conventional D-9/7 biorthogonal wavelet filters is shown in terms of coding efficiency.
International conference proceedings, English

Robust Auxiliary-Noise-Power Scheduling in Active Noise Control Systems with Online Secondary Path Modeling
S.Ahmed; M.T.Akhtar; X.Zhang
IEEE Trans. Audio, Speech and Language Processing, 21, 4, 749-761, Apr. 2013, Peer-reviwed
Scientific journal, English

2D ORTHOGONAL SYMMETRIC WAVELET FILTERS USING ALLPASS FILTERS
Xi Zhang
2013 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP), IEEE, 2631, 5618-5621, 2013, Peer-reviwed, This paper proposes a new class of 2D orthogonal symmetric wavelet filters using 2D nonseparable allpass filters. The proposed wavelet filters are based on the parallel structure of allpass filters with real-valued coefficients, which can be implemented with a low computational complexity and is robust to finite precision effects. The resulting wavelet bases are not only orthogonal, including perfect reconstruction (PR) condition, but also symmetric, whose analysis and synthesis filters have exactly linear phase response. It is also shown that the design problem of the proposed wavelet filters can be reduced to the phase approximation of the corresponding allpass filters. Therefore, it is easy to design this class of orthogonal symmetric wavelet filters by using the existing design methods of allpass filters. Finally, some examples are presented to demonstrate the effectiveness of the proposed orthogonal symmetric wavelet filters.
International conference proceedings, English

Online acoustic feedback mitigation with improved noise-reduction performance in active noise control systems
Shakeel Ahmed; Muhammad Tahir Akhtar; Xi Zhang
IET Signal Processing, 7, 6, 505-514, 2013, Peer-reviwed, The main focus of this paper is the acoustic feedback path neutralisation during online operation of the single-channel active noise control (ANC) systems. Invasive techniques, in which additive auxiliary noise is injected for online feedback path modelling (FBPM), degrade the noise-reduction performance of ANC systems. In the existing methods for online FBPM, additive auxiliary noise with fixed variance is injected during all operating conditions of ANC systems. In this paper, a scheduling strategy is proposed to have time-varying gain for additive auxiliary noise. The time-varying gain is computed on the basis of (i) the convergence status of the FBPM filter, and (ii) the power of the interference term in the error signal of the FBPM filter. Simulation results show that, compared to the existing methods, the proposed method can better achieve the conflicting requirements of fast convergence of the FBPM filter, and reduced steady-state power of the residual error at the error microphone. For sake of completeness, appendix presents typical simulation results when both the secondary path and feedback path are simultaneously identified during online operation of ANC systems. © The Institution of Engineering and Technology 2013.
Scientific journal, English

Hilbert Pair of Almost Symmetric Orthogonal Wavelets with Arbitrary Center of Symmetry
Dai-Wei Wang; Xi Zhang
2013 ASIA-PACIFIC SIGNAL AND INFORMATION PROCESSING ASSOCIATION ANNUAL SUMMIT AND CONFERENCE (APSIPA), IEEE, 232, 2013, Peer-reviwed, This paper proposes a new method for designing a class of Hilbert pairs of almost symmetric orthogonal wavelets with arbitrary center of symmetry. Two scaling lowpass filters are designed simultaneously to satisfy the specified degree of flatness of group delays, vanishing moments and orthogonality condition of wavelets, along with improved analyticity. Therefore, the resulting scaling lowpass filters have flat group delay responses and the specified number of vanishing moments. Moreover, the difference of the frequency responses between two scaling lowapss filters can be effectively minimized to improve the analyticity of complex wavelets. The condition of orthogonality is linearized, and then an iterative procedure is used to obtain the filter coefficients. Finally, several examples are presented to demonstrate the effectiveness of the proposed design procedure.
International conference proceedings, English

A simplified implementation of barbell lifting wavelets for scalable video coding
Zhuoliang Zhang; Xi Zhang; Songlin Sun; Xiaojun Jing; Hai Huang; Yueming Lu
IET Conference Publications, Institution of Engineering and Technology, 2013, 637, 514-519, 2013, Peer-reviwed, This paper proposes a simplified implementation of barbell lifting wavelets, which can be used in Wavelet-based Scalable Video Coding (WSVC). In the lifting scheme, barbell function is employed to generate prediction or update signals instead of only one pixel sample from single direction or each of bi-direction. The proposed method takes the corresponding pixel and some pixels around it into consideration and distributes the same weight to the neighbourhood pixels so as to simplify implementation. The method is compared with that without barbell lifting wavelets and a decreasing in standard deviation of residual images can be observed. Experiment results demonstrate that an improvement of coding efficiency is achieved with the proposed barbell lifting scheme.
International conference proceedings, English

IIR-Based DTCWTs With Improved Analyticity and Frequency Selectivity
Daiwei Wang; Xi Zhang
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 60, 11, 5764-5774, Nov. 2012, Peer-reviwed, In this paper, a new class of DTCWTs with improved analyticity and frequency selectivity is proposed by using general IIR filters with numerator and denominator of different degree. In the common-factor technique proposed by Selesnick, the maximally flat allpass filter was used to satisfy the half-sample delay condition. Thus, to improve the analyticity of complex wavelets, we present a method for designing allpass filters with the specified degree of flatness and equiripple phase response in the approximation band. Furthermore, to improve the frequency selectivity of scaling lowpass filters, we locate the specified number of zeros at z = -1 and minimize the stopband error. The design methods proposed in this paper use the well-known Remez exchange algorithm to approximate the equiripple response. Therefore, a set of filter coefficients can be easily obtained by solving the eigenvalue problem. Finally, we investigate the performance on the proposed DTCWTs through several design examples. It is shown that the conventional DTCWTs proposed by Selesnick are only the special cases of DTCWTs proposed in this paper.
Scientific journal, English

An Effective Wavelet-based Scheme for Multi-focus Image Fusion
G.F.Shao; X.Zhang
Proc. of TriSAI 2012, S-1-1, Sep. 2012, Peer-reviwed
International conference proceedings, English

PERFORMANCE INVESTIGATION ON DTCWT BASED ON THE COMMON FACTOR TECHNIQUE
Dai-wei Wang; Xi Zhang
2012 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP), IEEE, 3867, 3489-3492, 2012, Peer-reviwed, This paper investigates the performance on a class of DTCWTs based on the common factor technique. The common factor technique was first proposed in [6] by Selesnick, where two corresponding scaling lowpass filters are required to satisfy the half-sample delay condition, and then was modified to improve the analyticity [9] and frequency selectivity [8]. The analyticity of complex wavelet can be improved by minimizing the phase error in the approximation band of allpass filters with given flatness condition. The frequency selectivity of scaling lowpass filters can be improved by locating a specified number of zeros at z = -1 and applying the Remez exchange algorithm to minimize the magnitude response in the stopband. How to determine the approximation band and stopband will influence the performance of DTCWT. Therefore, this paper is dedicated to how to choose the approximation band and stopband properly.
International conference proceedings, English

Design of Q-Shift Filters With Flat Group Delay
Xi Zhang; Hiroaki Morihara
2012 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS 2012), IEEE, 2041, 2337-2340, 2012, Peer-reviwed, Q-shift filters have been proposed by Kingsbury for DTCWTs (Dual Tree Complex Wavelet Transforms), and are required to have linear phase responses. This paper proposes a new method for designing Q-shift filters with flat group delay responses. The proposed design method make use of the transfer function proposed by Gopinath, which satisfies both the specified degree of flatness for the group delay and the specified number of vanishing moments, i.e., the specified number of zeros at z = -1. Therefore, the design is reduced to how to force the filter to satisfy the condition of orthogonality. The design problem is linearized, and then an iterative procedure is used to obtain the filter coefficients. Finally, some examples are presented to demonstrate the effectiveness of the proposed design method.
International conference proceedings, English

Controlling Auxiliary-Noise-Power for Efficient Neutralization of Acoustic Feedback in Active Noise Control Systems
Shakeel Ahmed; Muhammad Tahir Akhtar; Xi Zhang
TENCON 2012 - 2012 IEEE REGION 10 CONFERENCE: SUSTAINABLE DEVELOPMENT THROUGH HUMANITARIAN TECHNOLOGY, IEEE, 1569627229, 2012, Peer-reviwed, The focus of this paper is acoustic feedback neutralization during online operation of single-channel active noise control (ANC) systems. Invasive techniques, in which additional auxiliary noise is injected, for online feedback path modeling and neutralization (FBPMN) comprise of three adaptive filters: 1) ANC filter, 2) Linear prediction filter, and 3) Feedback path modeling filter. In the existing methods, for online FBPMN, auxiliary noise with fixed variance is injected in all operating conditions, thus degrades the NRP of ANC systems at steady-state. In this paper a gain scheduling scheme is proposed to vary the auxiliary-noise-power (ANP). In proposed scheme the ANP is varied based on the convergence of both FBPMN filter and linear prediction filter. Simulation results show that proposed scheme can better achieve the conflicting requirements of fast convergence of FBPMN filter, and reduced steady-state residual error power at error microphone, compared to existing methods.
International conference proceedings, English

A New Phase-Factor Design Method for Hilbert-Pairs of Orthonormal Wavelets
Xi Zhang
IEEE SIGNAL PROCESSING LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 18, 9, 529-532, Sep. 2011, Peer-reviwed, A new method is proposed for designing Hilbert transform pairs of orthonormal wavelet bases with improved analyticity. Selesnick proposed a simple common factor technique for designing the Hilbert transform pairs in [7], where the phase factor is required to satisfy the half-sample delay condition, while the common factor is used to obtain the maximum number of vanishing moments and to satisfy the condition of orthonormality. To improve the analyticity of complex wavelets, we propose a novel method to design the phase factor by using the Remez exchange algorithm, so that the difference in the frequency response between two scaling lowpass filters is minimized. One design example is presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

DESIGN OF HILBERT TRANSFORM PAIRS OF ORTHONORMAL WAVELET BASES WITH IMPROVED ANALYTICITY
Xi Zhang
2011 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, IEEE, 2364, 4384-4387, 2011, Peer-reviwed, This paper proposes a class of Hilbert transform pairs of orthonormal wavelet bases with improved analyticity. To improve the analyticity of complex wavelet, a different allpass filter is used for the half-sample delay approximation. We present a design method for allpass filters with the specified degree of flatness at omega - 0 and equiripple phase response in the approximation band. Remez exchange algorithm is applied in the approximation band, and then a set of filter coefficients can be obtained easily by solving the eigen-value problem. Therefore, the equiripple phase response is attained through a few iterations. Furthermore, the corresponding filter banks are constructed from the designed allpass filters by using the method proposed in [7]. The resulting orthonormal wavelet bases possess the maximum number of vanishing moments. Finally, one example is presented to demonstrate the improvement of the analyticity.
International conference proceedings, English

Design of Q-shift filters with improved vanishing moments for DTCWT
Xi Zhang
Proceedings - International Conference on Image Processing, ICIP, 253-256, 2011, Peer-reviwed, Q-shift filters have been used in the Dual Tree Complex Wavelet Transform (DTCWT), and are required to have a well-controlled group delay. This paper proposes a new method for designing Q-shift filters with improved vanishing moments. The proposed design method allows the flatness condition of the group delay response to be included along with the vanishing moments and orthogonality of wavelets. Therefore, the resulting Q-shift filters possess flat group delay responses. Moreover, the number of vanishing moments can be arbitrarily specified by locating the desired number of zeros at z = -1. Finally, one example is presented to demonstrate the effectiveness of the proposed design method. © 2011 IEEE.
International conference proceedings, English

Design of Dual Tree Complex Wavelet Transforms Using IIR Digital Filters
Xi Zhang; D.W.Wang
Proceedings of 3rd International Symposium on Robot and Artificail Intelligence, 14, Jun. 2010
International conference proceedings, English

DESIGN OF ALLPASS FILTERS WITH SPECIFIED DEGREES OF FLATNESS AND EQUIRIPPLE PHASE RESPONSES
Xi Zhang
SIGMAP 2010: PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND MULTIMEDIA APPLICATION, INSTICC-INST SYST TECHNOLOGIES INFORMATION CONTROL & COMMUNICATION, 15, 205-210, 2010, Peer-reviwed, This paper proposes a new method for designing allpass filters having the specified degrees of flatness at the specified frequency point(s) and equiripple phase responses in the approximation band(s). First, a system of linear equations are derived from the flatness conditions. Then, the Remez exchange algorithm is used to approximate the equiripple phase responses in the approximation band(s). By incorporating the linear equations from the flatness conditions into the equiripple approximation, the design problem is formulated as a generalized eigenvalue problem. Therefore, we can solve the eigenvalue problem to obtain the filter coefficients, which have the equiripple phase response and satisfy the specified degrees of flatness simultaneously. Furthermore, a class of BR filters composed of allpass filters are introduced as one of its applications, and it is shown that IIR filters with flat passband (or stopband) and equiripple stopband (or passband) can be designed by using the proposed method. Finally, some examples are presented to demonstrate the effectiveness of the proposed design method.
International conference proceedings, English

FLICKER REDUCTION FOR MOTION JPEG2000 USING WAVELET THRESHOLDING
Xi Zhang; Atsushi Tanaka
2010 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING, IEEE, 2375, 2529-2532, 2010, Peer-reviwed, Flickering is a temporal visual artifact that impairs significantly the visual quality of the compressed videos. Motion JPEG2000 is a wavelet-based intraframe video codec, and has also a drawback of flicker artifact. In this paper, we introduce a new approach to flicker reduction of videos compressed by Motion JPEG2000 by using wavelet thresholding. We view this flicker reduction as a denoising problem in the temporal domain, and apply the excellent denoising property of wavelet thresholding in solving this flicker reduction problem. Compared with the conventional methods reported in the literature, It is shown from our experimental results that our wavelet-based method both suppresses the flicker artifact and achieve an improvement in PSNR and in TI.
International conference proceedings, English

Design of Hilbert transform pairs of orthonormal wavelet bases using IIR filters
Dai-Wei Wang; Xi Zhang
ISCIT 2010 - 2010 10th International Symposium on Communications and Information Technologies, 130, 554-559, 2010, Peer-reviwed, Conventionally, FIR filters have been often used to design the dual tree complex wavelet transforms (DTCWTs), where two real orthonormal wavelet bases form a Hilbert transform pair, whereas IIR filters are seldom used, although they require a lower computational complexity than FIR filters. In this paper, a new class of Hilbert transform pairs of orthonormal wavelet bases is proposed by using general IIR filters. To obtain the maximum number of vanishing moments, the conventional design methods located as many zeros as possible at z = -1. This paper proposes a new design method for DTCWTs by locating a specified number of zeros at z = -1 and minimizing the stopband error. The proposed method uses the well-known Remez exchange algorithm to approximate an equiripple magnitude response in the stopband. Therefore, a set of filter coefficients can be easily obtained by solving the eigenvalue problem. Furthermore, the optimal solution is attained through a few iterations. The advantage of the proposed method is that the number of zeros at z = -1 can be specified arbitrarily and an improved frequency selectivity can be obtained. ©2010 IEEE.
International conference proceedings, English

Design of FIR Halfband Filters for Orthonormal Wavelets Using Remez Exchange Algorithm
Xi Zhang
IEEE SIGNAL PROCESSING LETTERS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 16, 9, 814-817, Sep. 2009, Peer-reviwed, A new method is presented for designing FIR halfband filters for orthonormal wavelets. When the filter degree, number of vanishing moments, and tolerance error in passband/stopband are specified, the filters with the maximal passband/stopband width are designed by using Remez exchange algorithm. It is well-known that Remez exchange algorithm is an efficient approach for equiripple design of FIR linear phase filters. Therefore, FIR halfband filters with a given tolerance error can be easily obtained. Finally, some examples are presented to demonstrate the effectiveness of the proposed design method. SPL EDICS : DSP-FILT
Scientific journal, English

Maxflat Fractional Delay IIR Filter Design
Xi Zhang
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 57, 8, 2950-2956, Aug. 2009, Peer-reviwed, Fractional delay (FD) filters are an important class of digital filters and are useful in various signal processing applications. This paper discusses a design problem of FD infinite-impulse-response (IIR) filters with the maxflat frequency response in frequency domain. First, a flatness condition of FD filters at an arbitrarily specified frequency point is described, and then a system of linear equations is derived from the flatness condition. Therefore, a set of filter coefficients can be easily obtained by solving this system of linear equations. For a special case in which the frequency response is required to be maxflat at omega = 0 or pi, a closed-form expression for its filter coefficients is derived by solving a linear system of Vandermonde equations. It is also shown that the existing maxflat FD finite-impulse-response (FIR) and IIR filters are special cases of the FD IIR filters proposed in this paper. Finally, some examples are presented to demonstrate the effectiveness of the proposed filters.
Scientific journal, English

DESIGN OF HILBERT TRANSFORM PAIRS OF ORTHONORMAL WAVELET BASES USING REMEZ EXCHANGE ALGORITHM
Xi Zhang
2009 16TH IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING, VOLS 1-6, IEEE, 3286, 3813-3816, 2009, Peer-reviwed, This paper proposes a new method for designing Hilbert transform pairs of orthonormal wavelet bases proposed by Selesnick in [9]. The conventional method located as many zeros as possible at z = 1 to obtain the maximum number of vanishing moments. In this paper, we specify the number of zeros at z = 1, and then use the remaining degree of freedom to get the best possible frequency selectivity. The Remez exchange algorithm is applied in the stopband to approximate the equiripple magnitude response. Therefore, a set of filter coefficients can be obtained easily by solving a system of linear equations. Furthermore, the optimal solution is attained through a few iterations. Since the number of zeros at z = 1 can be specified arbitrarily, a new class of Hilbert transform pairs of orthonormal wavelet bases with the specified number of vanishing moments can be generated.
International conference proceedings, English

Closed-Form Design of Maxflat Fractional Delay IIR Filters
X.Zhang
Proc. of 10th IASTED SIP'08, 623-042, Aug. 2008, Peer-reviwed
International conference proceedings, English

Design of maximally flat IIR filters with flat group delay responses
Xi Zhang
SIGNAL PROCESSING, ELSEVIER SCIENCE BV, 88, 7, 1792-1800, Jul. 2008, Peer-reviwed, Digital filters with linear phase responses, that is, constant group delay responses are needed in many applications for signal and image processing. In this paper, a novel method is proposed for designing maximally flat IIR filters with flat group delay responses in the passband. First, a system of linear equations are derived from the flatness conditions of IIR filters given in the passband and stopband, respectively. Then, a set of filter coefficients can be easily obtained by simply solving this system of linear equations. In the proposed design method, the flatness of the frequency response can be specified arbitrarily. The design of lowpass filters are described in detail, and bandpass and bandstop filters are given also. Moreover, the causality and stability of the proposed maximally flat IIR filters are examined by designing various IIR filters with different group delays. It is shown from the experimental results that the obtained maximally flat IIR filters are causal stable if the group delay is set to be larger than a specific value. Finally, some design examples are presented to demonstrate the effectiveness of the proposed maximally flat IIR filters. (c) 2008 Elsevier B.V. All rights reserved.
Scientific journal, English

LOSSLESS IMAGE COMPRESSION USING 2D ALLPASS FILTERS
Xi Zhang; Kosuke Ohno
2008 IEEE International Conference on Image Processing, Proceedings, IEEE, 1037-1040, 2008, Peer-reviwed, In this paper, a reversible integer-to-integer wavelet transform based on nom separable 2D allpass filters is proposed for lossless image coding. The number of rounding operations included in the reversible wavelet transform is reduced by using non-separable 2D allpass filters, thus it is expected to get better coding performance. The lossless coding performance of the proposed reversible wavelet transform is evaluated and compared with the conventional separable wavelet transforms. It is shown from the experimental results that the proposed non separable 2D reversible wavelet tranform can achieve better lossless coding performance than the conventional separable wavelet transforms, including the D-5/3 wavelet tranform in the JPFG 2000.
International conference proceedings, English

オールパスフィルタを用いた画像ロシー・ロスレス統一符号化
張煕; 大野弘祐
電気通信普及財団研究調査報告書, 22, 298-305, Dec. 2007
Research society, Japanese

通過域平たん阻止域等リプル振幅特性をもつ平たん群遅延IIRフィルタの一設計法
張煕; 相澤正智; 吉川敏則
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J90-A, 7, 578-587, Jul. 2007, Peer-reviwed, 本論文では,通過域に平たん群遅延特性を有する通過域平たん阻止域等リプルIIRフィルタの一設計法を提案する.最初に,通過域における振幅と群遅延特性の平たん条件を示し,その条件からフィルタ係数に関する線形方程式を導出する.そして,阻止域の指定された周波数点に零点を配置することにより,通過域に平たん振幅と群遅延かつ阻止域に指定された零点を有するIIRフィルタが設計できる.次に,阻止域に零点を等間隔に配置して得られたフィルタ係数を初期値とし,Remezアルゴリズムを阻止域に適用する.このフィルタ設計問題は行列の固有値問題として定式化できるので,固有値問題を解いて,フィルタ係数が得られる.更に,固有値問題の反復処理により,阻止域に等リプル振幅特性を達成することができる.最後に,設計例として,低域通過,帯域通過,帯域阻止フィルタを示す.
Scientific journal, Japanese

Closed-form design of maxflat R-regular IIR Mth-band filters using blockwise waveform moments
Xi Zhang; Dong Fang Ge
2007 15th International Conference on Digital Signal Processing, DSP 2007, 1440, 296-299, 2007, Peer-reviwed, Mth-band filters are an important class of digital filters and are often used in multirate digital signal processing systems, filter banks and wavelets. This paper considers the design problem of the maxflat R-regular IIR Mth-band filters with arbitrarily specified group delays, and gives a new closed-form expression for its filter coefficients. The filter coefficients are directly derived by solving a linear system of Vandermonde equations, which are obtained from the regularity condition of the maxflat R-regular Mth-band filters via the blockwise waveform moments. Finally, some examples are designed to demonstrate the effectiveness of the proposed maxflat R-regular IIR Mth-band filters. ©2007 IEEE.
International conference proceedings, English

Closed-form design of maxflat R-REGULAR IIR MTH-band filters using blockwise waveform moments
Xi Zhang; Fang G. E. Dong
PROCEEDINGS OF THE 2007 15TH INTERNATIONAL CONFERENCE ON DIGITAL SIGNAL PROCESSING, IEEE, 29, 93341, 296-+, 2007, Peer-reviwed, Mth-band filters are an important class of digital filters and are often used in nrultirate digital signal processin.- systems. filter banks and wavelets. This paper considers the design problem of the maxflat R-rugular IIR Mth-band filters with arbitrarily specified group delays, and gives a new closed form expression for its filter coefficients. The filter coefficients ate directly derived by solving a linear system of Vandermonde equations, which are obtained from the regularity condition of the maxiflat R-regular Mth-band filters via the blockwise waveform moments. Finally, some examples are desgned to demonstrate the effectiveness of the proposed maxflat R-regular IIR Mth-bind Filters.
International conference proceedings, English

Hilbert transform pairs of orthonormal symmetric wavelet bases using allpass filters
Xi Zhang; Dong Fang Ge
2007 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING, VOLS 1-7, IEEE, I, 425-428, 2007, Peer-reviwed, This paper proposes a new class of Hilbert transform pairs of orthonormal symmetric wavelet bases. The associated orthonormal filter banks with exactly linear phase responses are realized by using complex and real allpass filters, respectively. The filter characteristics with the maximally flat responses are investigated to show the effectiveness of the proposed pairs.
International conference proceedings, English

Closed-form design of generalized maxflat R-Regular FIR Mth-band filters using waveform moments
Xi Zhang; Daisuke Kobayshi; Tatsuya Wada; Toshinori Yoshikawa; Yoshinori Takei
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 54, 11, 4214-4222, Nov. 2006, Peer-reviwed, Mth-band filters have found numerous applications in multirate signal processing systems, filter banks, and wavelets. In this paper, the design problem of generalized maxflat R-regular finite impulse response (FIR) Mth-band filters with a specified integer group delay at omega = 0 is considered, and the closed-form expression for its impulse response is presented. The filter coefficients are directly derived by solving a linear system of Vandermonde equations that are obtained from the regularity condition of the maxflat R-regular FIR Mth-band filters via the blockwise waveform moments. Differing from the conventional FIR Mth-band filters with exactly linear phase responses, the generalized FIR Mth-band filters proposed in this paper have an arbitrarily specified integer group delay at omega = 0. Moreover, a new efficient implementation of the generalized maxflat R-regular FIR Mth-band filters is proposed by making use of the relationship between the filter coefficients in the closed-form solution. Finally, several design examples are presented to demonstrate the effectiveness of the proposed FIR Mth-band filters.
Scientific journal, English

Design of IIR orthogonal wavelet filter banks using lifting scheme
Zhang, X; W Wang; T Yoshikawa; Y Takei
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 54, 7, 2616-2624, Jul. 2006, Peer-reviwed, The lifting scheme is well known to be an efficient tool for constructing second generation wavelets and is often used to design a class of biorthogonal wavelet filter banks. For its efficiency, the lifting implementation has been adopted in the international standard JPEG2000. It is known that the orthogonality of wavelets is an important property for many applications. This paper presents how to implement a class of infinite-impulse-response (IIR) orthogonal wavelet filter banks by using the lifting scheme with two lifting steps. It is shown that a class of IIR orthogonal wavelet filter banks can be realized by using allpass filters in the lifting steps. Then, the design of the proposed IIR orthogonal wavelet filter banks is discussed. The designed IIR orthogonal wavelet filter banks have approximately linear phase responses. Finally, the proposed IIR orthogonal wavelet filter banks are applied to the image compression, and then the coding performance of the proposed IIR filter banks is evaluated and compared with the conventional wavelet transforms.
Scientific journal, English

Reducing stopband peak errors of R-regular 4th-band linear phase FIR filters by superimposing
L Pe; T Yoshikawa; Y Takei; Zhang, X; Y Sugita
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E89A, 2, 615-619, Feb. 2006, Peer-reviwed, R-regular Mth band filters are, an important class of digital filters and are used in constructing Mth-band wavelet filter banks, where the regularity is essential. But this kind of filter has larger stopband peak errors compared with a minimax filter of the same length. In this paper, peak errors in stopband of R-regular 4th-band filters are reduced by means of superimposing two filters with successive regularities. Then the stopband peak errors in the resulting filters are compared with the original ones. The results show that the stopband peak errors are reduced significantly in the synthesized filter that has the same length as the longer one of the two original filters, at the cost of regularity.
Scientific journal, English

SNR-maximizing interpolation filters for band-limited signals with quantization
Y Takei; K Mogi; T Yoshikawa; Zhang, X
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 89, 1, 31-46, 2006, As an interpolation filter for sampling rate transformation, a half-band filter with a reduced amount of computation is often used. Due to the restrictions on its amplitude characteristic, it is not possible to sufficiently reduce the quantization noise of the transition region of the filter. In this paper, the output SNR of the L-interpolator filter is analyzed with a quantized band-limited signal as the input. A design method is proposed for the linear phase FIR filter maximizing the output SNR. For the design, both the SNR maximizing design within the Type I FIR filters and one supplemented with the restriction of the L-th band filter are presented. Each design is reduced to derivation of the solution of a system of linear equations with a coefficient matrix represented analytically. The filter based on the proposed method can attain an SNR not attainable under the sacrifice of the order in the conventional filter taking into account only the passband and the stopband. (c) 2005 Wiley Periodicals, Inc.
Scientific journal, English

Lossy to lossless image coding using a complex allpass filter
Xi Zhang; Noriaki Fukuda
2006 8TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING, VOLS 1-4, IEEE, 24J4, 01, 1141-+, 2006, Peer-reviwed, Since wavelet filters composed of a single complex allpass filter satisfy both of the conditions of orthonormality and symmetry, it is expected to obtain better coding performance than biorthogonal wavelets in image coding. This paper proposes an effective implementation of the orthonormal symmetric wavelets composed of a complex allpass filter for image coding. Firstly, an implementation of irreversible real-to-real wavelets for lossy coding is presented by realizing the complex allpass filter. Then, the reversible integer-to-integer wavelets is realized by utilizing the invertible implementation of complex allpass filter. Finally, the coding performance of the orthonormal symmetric wavelets is evaluated and compared with the D-9n and D-5/3 wavelets. It is shown from the experimental results that the allpass-based orthonormal symmetric wavelets can achieve better coding performance than the D-9/7 and D-5/3 wavelets.
International conference proceedings, English

Hilbert transform pairs of orthonormal symmetric wavelet bases using allpass filters
Xi Zhang; Dong Fang Ge
Proceedings - International Conference on Image Processing, ICIP, 1, I425-I428, 2006, This paper proposes a new class of Hubert transform pairs of orthonormal symmetric wavelet bases. The associated orthonormal filter banks with exactly linear phase responses are realized by using complex and real allpass filters, respectively. The filter characteristics with the maximally flat responses are investigated to show the effectiveness of the proposed pairs. © 2007 IEEE.
International conference proceedings, English

量子化された帯域制限信号に対するSNR最大化内挿フィルタ
武井由智; 茂木孝一; 吉川敏則; 張煕
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J88-A, 1, 39-53, Jan. 2005, Peer-reviwed, サンプリングレート変換で使われる内挿フィルタとして,一般的なフィルタより演算量の少ないハーフバンドフィルタがよく用いられるが,その振幅特性の制約により,フィルタの遷移域の量子化雑音を十分に減少させることができない.本論文では,量子化された帯域制限信号を入力信号とするL倍内挿フィルタの出力SNRの解析を行い,出力SNRを最大化する直線位相FIRフィルタの設計法を提案する.設計法は,Type I FIRフィルタの範囲でのSNR最大化設計,それにLthバンドフィルタの制約を加えた場合でのSNR最大化設計のそれぞれが示されるが,いずれの設計も解析的に表示できる係数行列をもつ線形方程式の求解に帰着する.提案法によるフィルタは,量子化雑音のみが存在する帯域におけるゲインを抑えることにより,従来の通過域及び阻止域のみを考慮したフィルタでは次数の犠牲のもとでも達成できなかったSNRを達成している.
Japanese

Lossy to lossless image compression using allpass filters
Zhang, X; K Kawai; T Yoshikawa; Y Takei
2005 International Conference on Image Processing (ICIP), Vols 1-5, IEEE, 5-8, 2005, Peer-reviwed, In this paper, an effective implementation of the allpass-based orthonormal symmetric wavelets is proposed for image compression. Since the arthonormal symmetric wavelets are used, it can be expected to get better compression performance than biorthogonal wavelets. Firstly, the implementation of irreversible real-to-real wavelets is presented and its decomposition process is shown by using allpass filters. Then, the realization of the reversible integer-to-integer wavelets is given by utilizing the invertible implementation of allpass filters. Finally, the coding performance of the orthonormal symmetric wavelets is evaluated and compared with the D-9/7 and D-5/3 wavelets. It is shown from the experimental results that the allpass-based orthonormal symmetric wavelets can achieve better compression performance than the D-9/7 and D-5/3 wavelets.
International conference proceedings, English

Design of IIR half-band filters with arbitrary flatness and its application to filter banks
R Yamashita; Zhang, X; T Yoshikawa; Y Takei
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 87, 1, 10-18, 2004, Peer-reviwed, Half-band filters are important for applications to multirate signal processing and wavelets. Previously, FIR half-band filters have mainly been treated. However, it should be recognized that the IIR filter can produce frequency characteristics similar to those of the FIR filter with a low order. Also, in the applications of filter banks and wavelets, design of a half-band filter is needed in which the degree of flatness can be specified arbitrarily. In the present paper, a new design method is proposed for an IIR half-band filter with an arbitrary degree of flatness. In the present design method, the analytical solution of the filter coefficients is given in the case of a maximally flat filter. Also, in the case of a specified degree of flatness, the amplitude error in the stopband can be specified in the design. Further, the stability of the filter is studied and then the minimum group delay for causal stability is clarified. Finally, the IIR half-band filter is applied to the design of a two-channel filter bank and the effectiveness of the present design method is proven. (C) 2003 Wiley Periodicals, Inc.
Scientific journal, English

Design of Chebyshev-type IIR filters with approximately linear phase characteristics
R Takeuchi; Zhang, X; T Yoshikawa; Y Takei
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 87, 2, 1-9, 2004, Peer-reviwed, Digital filters with a linear phase characteristic are needed in many applications for signal processing. In this paper, design of a Chebyshev-type IIR filter with approximate linear phase characteristics in the passband is described. First, it is shown that a flat stopband can easily be realized by placing multiple zeros at the specified frequency points in the stopband. Next, the complex Remez exchange algorithm is applied to the passband so that the filter design problem is formulated as an eigenvalue problem. Hence, by solving the eigenvalue problem, the filter coefficients can be derived easily. Further, by means of iterative calculations, an equiripple characteristic of the error function in the passband is obtained. Finally, it is shown that a reverse Chebyshev-type IIR filter with an approximate linear phase characteristic can also be obtained by parallel connection of the proposed Chebyshev-type filter and a delay line. (C) 2003 Wiley Periodicals, Inc.
Scientific journal, English

Lifting implementation of IIR orthogonal wavelet filter banks using allpass filters
Zhang, X; W Wang; T Yoshikawa; Y Takei
2004 47TH MIDWEST SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOL II, CONFERENCE PROCEEDINGS, IEEE, 10, 413-416, 2004, Peer-reviwed, The lifting scheme is well-known to be an efficient tool for constructing second generation wavelets, and is often used to design a class of biorthogonal wavelet filter banks. For its efficiency, the lifting implemantation has been also adopted in the international standard JPEG2000. It is known that the orthogonality of wavelets is an important property for many applications. This paper presents how to implement two band IIR orthogonal wavelet filter banks according to the lifting scheme. It is shown that a class of IIR orthogonal wavelet filter banks can be realized by using allpass filters in the lifting steps. Thus, the proposed filter banks have approximate linear phase responses. Finally, the proposed IIR orthogonal wavelet filter banks are applied to image lossless compression, and the coding performance is investigated.
International conference proceedings, English

A 2-D extension of the sampling algorithm for sparse Fourier representations
K Nishimura; Y Takei; T Yoshikawa; Zhang, X
2004 47TH MIDWEST SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOL II, CONFERENCE PROCEEDINGS, IEEE, 421, 129-132, 2004, Peer-reviwed, Recently, a very efficient sampling algorithm for finding a B-term Fourier representation of given 1-D discrete signal is presented [Gilbert, Guha, Indyk, Muthukrishnan, Strauss; STOC02]. In this papers we present a modified version of the algorithm, which can be applied to 2-D signals. As in the original algorithm, dependence of the running time on the signal length is polylogarithmic.
International conference proceedings, English

Design of IIR orthogonal wavelet filter banks using lifting scheme
Zhang, X; W Wang; T Yoshikawa; Y Takei
ICIP: 2004 INTERNATIONAL CONFERENCE ON IMAGE PROCESSING, VOLS 1- 5, IEEE, 2511-2514, 2004, Peer-reviwed, The lifting scheme is well-known to be an efficient tool for constructing second generation wavelets. and is often used to design a class of biorthogonal wavelet filterbanks. For its efficiency. the lifting implemantation has been also adopted in the international standard JPEG2000. It is known that the orthogonality of wavelets is an important property for many applications. This paper presents how to implement two band IIR orthogonal wavelet filter banks according to the lifting scheme. It is shown that a class of IIR orthogonal wavelet filter banks can be realized by using allpass filters in the lifting steps. Thus, the proposed filter banks have approximate linear phase responses. Finally, the proposed IIR orthogonal wavelet filter banks are applied to image lossless compression, and the coding performance is investigated.
International conference proceedings, English

FIRディジタルフィルタの複素チェビシェフ近似
張煕,中山悟; 吉川敏則; 武井由智
長岡技術科学大学研究報告, 25, 15-21, Dec. 2003, Peer-reviwed
Research institution, Japanese

Derivative-controlled design of linear-phase FIR filters via waveform moments
Y Takei; K Nagato; T Yoshikawa; Zhang, X
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 51, 10, 2559-2567, Oct. 2003, Peer-reviwed, A new method for designing linear-phase finite impulse response (FIR) filters is proposed by using the blockwise waveform moments. The proposed method yields linear-phase FIR filters whose magnitude response and its derivatives to a certain order take the prescribed values at the equally spaced frequency points. The design procedure only needs to solve a system of linear equations, whose size is slightly smaller than the degree of the resulting filter. In addition, the inversion of the linear equations can be essentially precomputed. Therefore, the proposed design method is computationally efficient. In particular, for some important cases, i.e., the maximally flat R-regular Lth-band FIR filters, a closed-form formula can be,obtained. It is also shown that the resulting R-regular Lth-band FIR filters have the zero intersymbol interference property.
Scientific journal, English

回転不変モーメントを入力とするニューラルネットを用いた画像重ね合わせ用対応点候補の自動選定
奥村浩; 渡邉勝之; 末崎将司; 梶原康司; 張煕; 吉川敏則
写真測量とリモートセンシング, Japan Society of Photogrammetry and Remote Sensing, 42, 3, 17-28, Jun. 2003, Peer-reviwed, Accuracy of image registration is severely affected by that of corresponding control point (CCP) selection in remote sensing or GIS (Geographic Information System) . In this paper, a new automated system for CCP candidate selection from target images is proposed. In the system, first, grayscale image within a quasicircular field of view (FOV) is transformed into binary one after intensity modification for the several extreme intensity pixels. Next, the binary image is transformed into a rotation invariant intermediate representation. Finally, the system determines whether the central pixel of the FOV is appropriate as the CCP by using well-trained 3-layer feedforward artificial neuralnet. Pseudo Zernike moments are employed as the intermediate representation. Consequently, without selection accuracy deterioration, we achieve quite fewer training patterns, shorter training time, and higher noise tolerance in comparison with conventional neuralnet-based systems.
Scientific journal, Japanese

空間周波数領域における回転不変モーメントを用いたリモートセンシング画像のテクスチャ定量化手法
奥村浩; 成田常晃; 前田優; 梶原康司; 張煕; 吉川敏則; 新井康平
日本リモートセンシング学会誌, 日本リモ-トセンシング学会, 23, 2, 137-146, Jun. 2003, Peer-reviwed
Scientific journal, Japanese

近似的直線位相特性を有するチェビシェフ型IIRフィルタの設計
竹内良介; 張煕; 吉川敏則; 武井由智
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J86-A, 4, 364-372, Apr. 2003, Peer-reviwed, 直線位相特性を有するディジタルフィルタは信号処理の多くの応用において必要である.本論文では,通過域に近似的直線位相特性を有するチェビシェフ型IIRフィルタの設計について述べる.まず,阻止域の指定された周波数点に多重零点を配置することにより,フィルタの平たんな阻止域が容易に実現できることを示す.次に,通過域に複素Remezアルゴリズムを適用し,フィルタの設計問題を固有値問題として定式化する.よって,固有値問題を解くことにより,フィルタ係数が容易に求められる.更に,反復計算を行い,通過域における誤差関数の等リプル特性を得る.最後に,提案したチェビシェフ型フィルタと遅延器を並列接続し,近似的直線位相特性を有する逆チェビシェフ型IIRフィルタも同時に得られることを示す.
Scientific journal, Japanese

On the distribution of fractional linear congruential pseudorandom numbers
Y Takei; T Yoshikawa; Zhang, X
IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E86D, 2, 276-284, Feb. 2003, Peer-reviwed, As pseudorandom number generators for Monte Carlo simulations, inversive linear congruential generators (ICG) have some advantages compared with traditional linear congruential generators. It has been shown that a sequence generated by an ICG has a low discrepancy even if the length of the sequence is far shorter than its period. In this paper, we formulate fractional linear congruential generators (FCG), a generalized concept of the inversive linear congruential generators. It is shown that the sequence generated by an FCG is a geometrical shift of a sequence from an ICG and satisfies the same upper bounds of discrepancy. As an application of the general formulation, we show that under certain condition, "Leap-Frog technique," a way of splitting a random number sequence to parallel sequences, can be applied to the ICG or FCG with no extra cost on discrepancy.
Scientific journal, English

IIR直線位相フィルタバンクを用いた画像ロスレス符号化
阿部洋; 張煕; 吉川敏則; 武井由智
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J86-A, 2, 179-186, Feb. 2003, Peer-reviwed, 画像ウェーブレッド符号化においては,従来,FIR直線位相フィルタバンクが主に用いられてきた.周知のように,FIRフィルタに比べ,IIRフィルタは同等な次数でより良い周波数特性が得られるため,画像圧:縮に適用する際,より良い圧縮性能が期待できる.本論文では,IIR直線位相フィルタバンクを画像ロスレス符号化に適用し,リフティング構成に基づいた有効な実現方法を提案する.提案するIIRフイルタバンクでは,有名なリフティング構成を用いるため,フィルタリング後に整数化処理を行い,ロスレス符号化に必要な可逆ウェーブレット変換が容易に実現できる.また,各々の自然画像に対し,それらの画像に適したフィルタパラメータを実験結果から明らかにする.最後に,IIR直線位相フィルタバンクを使用することにより,従来のFIRフィルタより良い画像圧縮性能が得られることを示す.
Scientific journal, Japanese

任意の平坦度を有するIIRハーフバンドフィルタの設計とフィルタバンクへの応用
山下亮; 張煕; 吉川敏則; 武井由智
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J86-A, 2, 134-141, Feb. 2003, Peer-reviwed, ハーフバンドフィルタはマルチレート信号処理やウェーブレットなどの応用において重要である.従来,FIRハーフバンドフィルタが主に取り扱われてきたが,IIRフィルタは低次数でFIRフィルタと同等の周波数特性を得ることができる.また,フィルタバンクやウェーブレットなどの応用では,平たん度が任意に指定できるハーフバンドフィルタの設計が必要である.本論文では,任意の平たん度を有するIIRハーフバンドフィルタの新しい設計法を提案する.本設計法では,最大平たんフィルタの場合,フィルタ係数の解析解を与える.また,指定された平たん度の場合,阻止域の振幅誤差を指定して設計できることを示す.更に,フィルタの安定性について調べ,因果的安定となるときの最小群遅延を明らかにする.最後に,IIRハーフバンドフィルタを2チャネルフィルタバンクの設計に適用し,本設計法の有効性を示す.
Scientific journal, Japanese

On the distribution of fractional linear congruential pseudorandom numbers
Yoshinori Takei; Toshinori Yoshikawa; Xi Zhang
IEICE Transactions on Information and Systems, Institute of Electronics, Information and Communication, Engineers, IEICE, E86-D, 2, 276-284, 2003, As pseudorandom number generators for Monte Carlo simulations, inversive linear congruential generators (ICG) have some advantages compared with traditional linear congruential generators. It has been shown that a sequence generated by an ICG has a low discrepancy even if the length of the sequence is far shorter than its period. In this paper, we formulate fractional linear congruential generators (FCG), a generalized concept of the inversive linear congruential generators. It is shown that the sequence generated by an FCG is a geometrical shift of a sequence from an ICG and satisfies the same upper bounds of discrepancy. As an application of the general formulation, we show that under certain condition, "Leap-Frog technique," a way of splitting a random number sequence to parallel sequences, can be applied to the ICG or FCG with no extra cost on discrepancy.
International conference proceedings, English

Design of full band IIR digital differentiators
X.Zhang; T.Yoshikawa
PROCEEDINGS OF 2003 INTERNATIONAL CONFERENCE ON NEURAL NETWORKS & SIGNAL PROCESSING, PROCEEDINGS, VOLS 1 AND 2, IEEE, 652-655, 2003, Peer-reviwed, This paper presents an efficient method for designing full band IIR digital differentiators in the complex Chebyshev sense. The proposed method is based on the formulation of a generalized eigenvalue problem by using the Remez multiple exchange algorithm. Therefore, a set of filter coefficients can be easily obtained by solving the eigenvalue problem to find the absolute minimum eigenvalue, and then the complex Chebyshev approximation is attained through a few iterations starting from a given initial guess. The proposed algorithm is computationally efficient because it not only retains the speed inherent in the Remez: exchange algorithm, but also simplifies the interpolation step. One design example is presented and compared with the conventional methods. It can be seen that the design results obtained by using the proposed method are better than that in the conventional methods.
International conference proceedings, English

Closed-form design of maximally flat IIR half-band filters
Zhang, X; K Amaratunga
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 49, 6, 409-417, Jun. 2002, Peer-reviwed, Half-band (HB) filters are of great importance and are often used in multirate digital signal processing systems, filter banks and wavelets. In this paper, a new closed-form expression for the transfer function of the maximally flat (MF) infinite-impulse, response (IIR) HB filters is presented. The filter coefficients are directly obtained by solving a linear system of Vandermonde equations that are derived from the maximal flatness conditions. The proposed IIR half-band filters are more general than the existing half-band filters, because they include the conventional finite-impulse response (FIR) half-band filters with exactly linear phase, the generalized FIR half-band filters with approximately linear phase and the all-pass-based IIR half-band filters, as special cases. Furthermore, the causal stable IIR HB filters and the IIR HB filters with exactly linear phase can be realized also. Finally, some design examples are presented to demonstrate the effectiveness of the proposed IIR HR filters.
Scientific journal, English

Wavelet-based image coding using all-pass filters
S Kamimura; Zhang, X; T Yoshikawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 85, 2, 13-21, 2002, Peer-reviwed, FIR wavelet filters are mainly used in conventional wavelet-based image coding. However, FIR filters, except for the Haar wavelet, cannot satisfy both the exactly linear phase and orthonormality conditions. For example, the well-known Daubechies-9/7 wavelet is biorthogonal. In this paper, an effective implementation of the all-pass-based wavelet filters is presented for wavelet-based image coding. Since all-pass filters are IIR, both the exactly linear phase and orthonormality conditions can be simultaneously satisfied, so that better compression performance can be expected, Also, IIR filters can be realized with a lower computational complexity than can FIR filters. Finally, the proposed IIR wavelet filters are evaluated by using SPIHT to compress the practical images, and the influence of the all-pass filters and delay elements on the compression performance is investigated. It is shown through the experimental results that the IIR wavelet filters proposed in this paper have a lower computational complexity than the Daubechies-9/7 wavelet, with a comparable compression performance. (C) 2001 Scripta Technica, Electron Comm Jpn Pt 3, 85(2): 13-21, 2002.
Scientific journal, English

Closed-form design of maximally flat IIR half-band filters
Zhang, X; T Yoshikawa
2002 6TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING PROCEEDINGS, VOLS I AND II, IEEE, 124-127, 2002, Peer-reviwed, In this paper, a new closed-form expression for the transfer function of the maximally flat (MF) IIR half-band (HB) filters is presented. The filter coefficients are directly obtained by solving a linear system of Vandermonde equations that are derived from the maximal flatness conditions. The proposed IIR half-band filters are more general than the existing half-band filters., because they include the conventional FIR half-band filters with exactly linear phase, the generalized FIR half-band filters with approximately linear phase, and the allpass-based IIR half-band filters, as special cases. Furthermore, the IIR HB filters with exactly linear phase and the causal stable IIR HB filters can, be realized also. Finally, some design examples are presented to demonstrate the effectiveness of the proposed IIR HB filters.
International conference proceedings, English

A new class of orthonormal symmetric wavelet bases using a complex allpass filter
Zhang, X; A Kato; T Yoshikawa
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 49, 11, 2640-2647, Nov. 2001, Peer-reviwed, This paper considers the design of the WSS paraunitary filterbanks composed of a single complex allpass filter and gives a new class of real-valued orthonormal symmetric wavelet bases. First, the conditions that the complex allpass filter has to satisfy are derived from the symmetry and orthonormality conditions of wavelets, and its transfer function is given to satisfy these conditions. Second, the paraunitary filter banks are designed by using the derived transfer function from the viewpoints of the regularity and frequency selectivity. A new method for designing the proposed paraunitary filterbanks with a given degrees of flatness is presented. The proposed method is based on the formulation of a generalized eigenvalue problem by using the Remez exchange algorithm. Therefore, the filter coefficients can be easily obtained by solving the eigenvalue problem, and the optimal solution is attained through a few iterations. Furthermore, both the maximally flat and minimax solutions are also included in the proposed method as two specific cases. The maximally flat filters have a closed-form solution without any iteration. Finally, some design examples are presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

A new class of complex compact-supported orthonormal symmlets
Zhang, X; T Yoshikawa
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E84A, 7, 1740-1746, Jul. 2001, Peer-reviwed, This paper presents a new class of complex-valued compact-supported orthonormal symmlets. Firstly, some properties of complex-valued compact-supported orthonormal symmlets are investigated, and then it is shown that complex-valued symmlets call be generated by real-valued half-band filters. Therefore, the construction of complex-valued symmlets can be reduced to the design of real-valued half-band filters. Next, a design method of real-valued half-band FIR filters with some flatness requirements is proposed. For the maximally Bat half-band filters, a closed-form solution is given. For the filter design with a given degree of flatness, the design problem is formulated in the form of linear system by using tilt: Remez exchange algorithm and considering the given flatness condition. Therefore, a set of filter coefficients can be easily computed by solving a set of linear equations, and the optimal solution is obtained through a few iterations. Finally, some design examples are presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

全域通過フィルタを用いた画像ウェーブレット符号化
上村晴也; 張煕; 吉川敏則
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J84-A, 1, 13-21, Jan. 2001, Peer-reviwed, 従来の画像ウェーブレット符号化では, FIRウェーブレットフィルタが主に使用されている.しかし, FIRフィルタの場合, Haarウェーブレット以外は, 完全直線位相と正規直交条件を同時に満たすことができない.例えば, よく知られているDaubechies-9/7ウェーブレットは双直交である.本論分では, 画像ウェーブレット符号化に全域通過フィルタより構成されたウェーブレットフィルタを適用し, その有効な実現方法を提案する.全域通過フィルタはIIRフィルタであるので, 完全直線位相と直交条件を同時に満たすことができ, より良い圧縮性能が期待できる.また, FIRフィルタに比べて少ない演算量で実現可能である.最後に, SPIHTを用いて実際に画像圧縮を行い, 提案したIIRウェーブレットフィルタを評価し, 全域通過フィルタと遅延器の次数が圧縮性能に与える影響を明らかにする.実験結果からわかるように, 本論文で提案したIIRウェーブレットフィルタはDaubechies-9/7ウェーブレットと比較すると, 少ない演算量で同等以上の圧縮性能が得られる.
Scientific journal, Japanese

Design of IIR digital filters with flat passband and equiripple stopband responses
Zhang, X; T Yoshikawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 84, 11, 37-44, 2001, Peer-reviwed, In the design of IIR digital filters, the method that utilizes the classic analog filter design theory to design analog filters and then obtain the corresponding digital filters by s-z transformation is well-known. However, IIR digital filters obtained via the bilinear s-z transformation have just equal-order numerator and denominator. Having unequal-order numerator and denominator will give more degrees of freedom in filter design. In this paper, we consider the design of IIR digital filters with unequal-order numerator and denominator, and propose a method for designing the flat passband and equiripple stopband filters in z-domain directly. First, we present a design method of IIR filters with flat stopband and equiripple passband responses. The flat stopband response can be easily obtained only by locating multiple zeros on the specified frequency points, while the equiripple passband response can be designed by using the Remez exchange algorithm and specifying the maximum magnitude error. Second, we can obtain IIR filters with flat passband and equiripple stopband responses via a magnitude transformation such that the passband and stopband become the corresponding stopband and passband, respectively. However, the numerator order of IIR filters obtained by the above method is equal to or higher than the denominator. Finally, we consider the design of IIR filters that have lower-order numerator than denominator, and present a method for designing the flat passband and equiripple stopband filters directly. (C) 2001 Scripta Technica.
Scientific journal, English

Complex Chebyshev approximation for IIR digital filters based on eigenvalue problem
Zhang, X; K Suzuki; T Yoshikawa
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 47, 12, 1429-1436, Dec. 2000, Peer-reviwed, This paper presents an efficient method for designing complex infinite impulse response digital filters in the complex Chebyshev sense. The proposed method is based on the formulation of a generalized eigenvalue problem by using the Remez multiple exchange algorithm, Hence, the filter coefficients can be easily obtained by solving the eigenvalue problem to find the absolute minimum eigenvalue, and then the complex Chebyshev approximation is attained through a few iterations starting from a given initial guess. The proposed algorithm is computationally efficient because it not only retains the speed inherent in the Remez exchange algorithm but also simplifies the interpolation step. Some design examples art: presented and compared with the conventional methods. It is shown that the results obtained by using the method proposed in this paper are better than those obtained by the conventional methods.
Scientific journal, English

Design of orthonormal symmetric wavelet filters using real allpass filters
Zhang, X; T Muguruma; T Yoshikawa
SIGNAL PROCESSING, ELSEVIER SCIENCE BV, 80, 8, 1551-1559, Aug. 2000, Peer-reviwed, In this paper, a class of real-valued orthonormal symmetric wavelet filters is constructed by using allpass filters, and a new method for designing the allpass-based wavelet filters with the given degrees of flatness is proposed. The proposed method is based on the formulation of a generalized eigenvalue problem by using the Remez exchange algorithm and considering the flatness condition. Therefore, a set of filter coefficients can be easily computed by solving the eigenvalue problem, and the optimal solution in the minimax sense is obtained through a few iterations. Furthermore, the design of the maximally flat allpass-based wavelet filters is also included as a specific case, but it has a closed-form solution that is the same as in Selesnick (IEEE Trans. Signal Process. 46 (4) (April 1998) 1138-1141) so that the iteration procedure is not needed. Finally, some examples are designed to investigate the filter characteristics, and it is shown that the number of delay elements strongly influences the filter magnitude responses. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Wavelet-based Image Coding Using Allpass Filters
X.Zhang; S.Kamimura; T.Yoshikawa
Proceedings of SCI'2000/ISAS'2000, Jul. 2000, Peer-reviwed
International conference proceedings, English

Complex Chebyshev approximation for IIR digital filters
Zhang, X; K Suzuki; T Yoshikawa
ISCAS 2000: IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS - PROCEEDINGS, VOL I, IEEE, 371-374, 2000, Peer-reviwed, This paper presents an efficient method for designing complex IIR digital filters in the complex Chebyshev sense. The proposed method is based on the formulation of a generalized eigenvalue problem by using the Remez multiple exchange algorithm. Hence, the filter coefficients can be easily obtained by solving the eigenvalue problem to find the absolute minimum eigenvalue, and then the complex Chebyshev approximation is attained through a few iterations starting with a given initial guess. The proposed algorithm is computationally efficient. One example is designed and compared with one proposed by Chen and Parks. It is shown that the results obtained by using the method proposed in this paper are better than the conventional methods.
International conference proceedings, English

Design of low-delay FIR half-band filters with arbitrary flatness and its application to filter banks
Zhang, X; K Intosume; T Yoshikawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 83, 10, 1-9, 2000, Peer-reviwed, Half-band filters are a class of important filters among digital filters, and have been widely used in many applications such as filter banks and wavelets. The conventional methods are mainly concerned with FIR half-band filters with exactly linear phase. However, the exactly Linear phase filters have a drawback of large group delay when high-order filters are required. In this paper, the design of FIR half-band filters with a lower group delay is considered. In some applications of filter banks and wavelets, a flat magnitude response is required for the half-band filters. Therefore, a new method for designing low-delay FIR half-band filters with arbitrary flatness is proposed. In the proposed method, while taking the specified flatness condition into account, the design problem is formulated by using the complex Remez exchange algorithm in the stopband. Then, a set of filter coefficients can be easily obtained by solving a simple system of linear equations. The optimal solution with an equiripple response in the stopband is obtained by applying an iteration process. Finally, the proposed method is applied to the design of two-channel perfect reconstruction filter banks with low group delay to demonstrate its effectiveness. (C) 2000 Scripta Technica, Electron Comm Jpn Pt 3, 83(10): 1-9, 2000.
Scientific journal, English

任意の平坦度を有する低遅延FIRハーフバンドフィルタの設計とフィルタバンクへの応用
張煕; 猪爪堅太郎; 吉川敏則
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J82-A, 10, 1529-1537, Oct. 1999, Peer-reviwed, ハーフバンドフィルタはディジタルフィルタの中で重要なフィルタの一つであり,フィルタバンクやウェーブレットなどの応用によく使われている.従来の設計法では,主に完全直線位相特性を有するFIRハーフバンドフィルタを取り扱ってきたが,高次数のフィルタが必要な場合は,完全直線位相フィルタは大きな群遅延特性をもつ問題点がある.本論文では,群遅延特性がより低くなるようなFIRハーフバンドフィルタの設計を考える.また,フィルタバンクやウェーブレットなどの応用から,ハーフバンドフィルタに対して平たんな振幅特性が要求される.よって,ここでは,任意の平たん度を有する低遅延FIRハーフバンドフィルタの新しい設計法を提案する.本設計法では,与えられた平たん条件を考慮すると同時に,複素Remezアルゴリズムを用いて阻止域で定式化を行う.したがって,簡単な線形方程式を解くだけで,フィルタ係数が容易に求められる.そして,阻止域において,反復計算を行い,等リプル特性が得られる.最後に,低遅延特性を有する2チャネル完全再構成フィルタバンクの設計に本設計法を適用し,その有効性を示す.
Scientific journal, Japanese

Design of orthonormal IIR wavelet filter banks using allpass filters
Zhang, X; T Yoshikawa
SIGNAL PROCESSING, ELSEVIER SCIENCE BV, 78, 1, 91-100, Oct. 1999, Peer-reviwed, This paper presents a new method for designing two-band orthonormal IIR wavelet filter banks using allpass filters. It is well known that orthonormal wavelet bases can be generated by paraunitary filter banks. Thus, synthesis of orthonormal wavelet bases can be reduced to the design of paraunitary Biter banks. In this paper, two-band orthonormal IIR wavelet filter banks using a parallel connection of two real allpass filters or a complex allpass filter are examined. From the regularity of wavelets, an additional flatness condition is required to impose on the filter banks. Then, the design problem of orthonormal IIR wavelet filter banks with a given flatness condition is discussed. By considering the given flatness condition and using the Remez exchange algorithm, the design problem can be formulated in the form of an eigenvalue problem. Therefore, a set of filter coefficients can be easily gotten by solving the eigenvalue problem to compute the absolute minimum eigenvalue, and the optimal solution with an equiripple response can be obtained after using an iteration procedure. The proposed method is computationally efficient since the efficient Remez exchange algorithm is employed, and the flatness condition can be arbitrarily specified. Some design examples are presented to demonstrate the effectiveness of the proposed method. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Scientific journal, English

Texture Quantification Using Rotation Invariant Moments in Spatial Frequency Domain and Its Application to Texture Classification of Remotely Sensed Imagery
H.Okumura; K.Uchiyama; T.Narita; K.Kajiwara; X.Zhang; T.Yoshikawa
Proceedings of the EOS/SPIE Symposium on Remote Sensing, 3871-19, Sep. 1999, Peer-reviwed
International conference proceedings, English

Design of FIR Nyquist filters with low group delay
Z Xi; T Yoshikawa
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 47, 5, 1454-1458, May 1999, Peer-reviwed, A new method is proposed for designing FIR Nyquist filters sith zero-crossing impulse response and ion group delay. It is first shown that FIR Nyquist filters that satisfy the zero-crossing time-domain rendition have a frequency response property where both the magnitude and phase responses in the passband are dependent on the stopband response. Therefore, the design problem will become a magnitude approximation in the stopband. The proposed procedure is based on the formulation of a linear problem by using the multiple Remez exchange algorithm in the stopband directly. Hence, the filter coefficients can be computed by solving linear equations, and the optimal solution with an equiripple stopband response is easily obtained after applying an iteration procedure. Although the proposed Nyquist filters have an approximate linear phase response, its group delay is loner than the conventional FIR Nyquist filters. The proposed procedure is computationally efficient because it only solves a set of linear equations. Finally, the characteristics of the loft-delay FIR Nyquist filters are examined, and the performance is compared with the conventional RR Nyquist filters.
Scientific journal, English

通過域平坦阻止域等リプル特性を有するIIRディジタルフィルタの設計
張煕; 吉川敏則
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J82-A, 3, 317-324, Mar. 1999, Peer-reviwed, IIRディジタルフィルタの設計では, 従来のアナログフィルタ設計理論を利用して, アナログフィルタを設計し,s-z変換よりデイジタルフィルタを得る方法はもっとも一般的である. しかし, 双1次テ/変換等で得られたIIRデイジタルフィルタはその分子と分母が必ず同次数に限られる. 異なる次数の分子と分母をもつことはフィルタの設計により多くの自由度を与えることになる. よって, 本論文では, 分子と分母の次数が異なるIIRデイジタルフィルタの設計について考え, 通過域で平たん特性, 阻止域で等リプル特性となるよう, 直接z領域で設計する方法を提案する. まず, 阻止域平たん通過域等リプル特性をもつIIRフィノレタの設計法を示す. 阻止域の平たん特性は指定された周波数点に多重零点を配置するだけで簡単に得られる. また, 通過域の等リプル特性は最大振幅誤差を指定することにより, Remezアルゴリズムを用いて設計できる. 次に, 通過域を阻止域に, 阻止域を通過域になるように振幅変換を行い, 通過域平たん阻止域等リプル特性のIIRフィルタを求める. そのとき, 得られたIIRフィルタはその分子が必ず分母以上の次数になる. 最後に, 分子の次数が分母より低いIIRフイノレタの設計を考え, 通過域平たん阻止域等リプル特性を直接設計する方法を示す.
Scientific journal, Japanese

Design of IIR digital allpass filters based on eigenvalue problem
Zhang, X; H Iwakura
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 47, 2, 554-559, Feb. 1999, Peer-reviwed, A new method is proposed for designing IIR digital allpass filters with an equiripple phase response that ran he proven to be optimal in the Chebyshev sense. The proposed procedure is based on the formulation of an eigenvalue Problem by using the Remez exchange algorithm. Since there exists more than one eigenvalue in the general eigenvalue problem, He introduce a new and very simple selection rule for the eigenvalue to be searched for, where the rational interpolation is performed if and only if the real maximum eigenvalue is chosen. Therefore, the solution of the rational interpolation problem can bf gotten by computing only one eigenvector corresponding to the real maximum eigenvalue, and the optimal filter coefficients are easily obtained through a few iterations without any initial guess of the solution. The design algorithm proposed in this correspondence not only retains the speed inherent in the Remez exchange algorithm but also simplifies the interpolation step because it has been reduced to the computation of the real maximum eigenvalue. Two examples are designed to demonstrate the effectiveness of this method.
Scientific journal, English

Design of two-channel IIR linear phase PR filter banks
Zhang, X; T Yoshikawa
SIGNAL PROCESSING, ELSEVIER SCIENCE BV, 72, 3, 167-175, Feb. 1999, Peer-reviwed, In this paper, a novel method is proposed for designing two-channel biorthogonal perfect reconstruction filter banks with exact linear phase using noncausal IIR filters. Since the structurally perfect reconstruction implementation is adopted, the proposed filter banks are guaranteed to be a perfect reconstruction even when all filter coefficients are quantized. From the view point of wavelets, design of biorthogonal IIR linear phase filter banks with an additional flatness constraint is considered. The proposed design method is based on the formulation of a generalized eigenvalue problem by using Remez exchange algorithm. Hence, the filter coefficients can be obtained by solving the eigenvalue problem to compute the positive minimum eigenvalue, and the optimal solution in the Chebyshev sense is easily obtained through a few iterations. The proposed procedure is computationally efficient, and the flatness constraint can be arbitrarily specified. Some design examples are presented to demonstrate the effectiveness of the proposed method. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Scientific journal, English

Design of biorthogonal FIR linear phase filter banks with structurally perfect reconstruction
Zhang, X; T Yoshikawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 82, 1, 1-8, Jan. 1999, Peer-reviwed, In the design of two channel perfect reconstruction filter banks, most of the conventional methods optimize the frequency response of each filter to meet the perfect reconstruction condition. However, quantization of the filter coefficients results in some errors in the frequency response, so it is not guaranteed that the perfect reconstruction condition is still satisfied. In this paper, we present a new method for designing biorthogonal FIR linear phase filter banks with structurally perfect reconstruction. From the perfect reconstruction condition, we first describe a class of structurally perfect reconstruction implementations. Since the proposed filter banks structurally satisfy the perfect reconstruction condition, the design problem becomes the magnitude approximation of the analysis or synthesis filters. Design of these filters can be reduced to the design of half-band filters. We then give a new method to design FIR linear phase half-band filters with arbitrary flatness. Therefore, the proposed filter banks can be designed easily by using the proposed method. Additionally, the magnitude responses of the low- and high-pass filters can be arbitrarily controlled by using two different half-band filters. (C) 1998 Scripta Technica.
Scientific journal, English

Design of symmetric orthonormal wavelet filters using a single complex allpass filter
Zhang, X; T Yoshikawa
ISCAS '99: PROCEEDINGS OF THE 1999 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOL 3, IEEE, 367-370, 1999, Peer-reviwed, This paper gives a new class of real-valued symmetric orthonormal wavelet filters by using a single complex allpass filter. Firstly, the conditions that the complex allpass filter has to satisfy are derived from the symmetric and orthonormal conditions of wavelets. Then, from the viewpoint of the wavelet regularity, a new method is proposed for designing the proposed symmetric orthonormal wavelet filters with the maximally flatness. In the proposed method, the maximally flat solutions can be easily obtained by solving a set of linear equations only.
International conference proceedings, English

Design of orthonormal IIR wavelet filter banks using allpass filters
Xi Zhang; Toshinori Yoshikawa
Signal Processing, Elsevier Science Publishers B.V., 78, 1, 91-100, 1999, Peer-reviwed, This paper presents a new method for designing two-band orthonormal IIR wavelet filter banks using allpass filters. It is well known that orthonormal wavelet bases can be generated by paraunitary filter banks, Thus, synthesis of orthonormal wavelet bases can be reduced to the design of paraunitary filter banks. In this paper, two-band orthonormal IIR wavelet filter banks using a parallel connection of two real allpass filters or a complex allpass filter are examined. From the regularity of wavelets, an additional flatness condition is required to impose on the filter banks. Then, the design problem of orthonormal IIR wavelet filter banks with a given flatness condition is discussed. By considering the given flatness condition and using the Remez exchange algorithm, the design problem can be formulated in the form of an eigenvalue problem. Therefore, a set of filter coefficients can be easily gotten by solving the eigenvalue problem to compute the absolute minimum eigenvalue, and the optimal solution with an equiripple response can be obtained after using an iteration procedure. The proposed method is computationally efficient since the efficient Remez exchange algorithm is employed, and the flatness condition can be arbitrarily specified. Some design examples are presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

Design of two channel stable IIR perfect reconstruction filter banks
Zhang, X; T Yoshikawa
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E81A, 8, 1592-1597, Aug. 1998, Peer-reviwed, In this paper, a novel method is proposed for designing two channel biorthogonal filter banks with general IIR filters, which satisfy both the perfect reconstruction and causal stable conditions. Since the proposed filter banks are structurally perfect reconstruction implementation, the perfect reconstruction property is still preserved even when all filter coefficients are quantized. The proposed design method is based on the formulation of a generalized eigenvalue problem by using Remez multiple exchange algorithm. Then. the filter coefficients can be computed by solving the eigenvalue problem, and the optimal solution is easily obtained through a few iterations. One design example is presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

ケプストラムモーメントを用いた縦続形 FIR フィルタの係数量子化効果の評価
吉川敏則; 池田高志; 張煕
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J81-A, 6, 1017-1020, Jun. 1998, Peer-reviwed, ディジタルフィルタ実現の際, その係数は有限語長に量子化される.本論文では, 縦続線FIRディジタルフィルタに着目し, 係数量子化による特性劣化の評価尺度として, ケプストラムモーメントを用い, 具体的な評価例を示した.
Scientific journal, Japanese

FIR ディジタルフィルタのパワースペクトルモーメントの定義とその特性
吉川敏則; 金永洛,張煕
電子情報通信学会論文誌(A), J81-A, 6, 1003-1005, Jun. 1998, Peer-reviwed
Scientific journal, Japanese

Design of orthonormal wavelet filter banks using the Remez exchange algorithm
Zhang, X; T Yoshikawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 81, 6, 1-8, Jun. 1998, Peer-reviwed, This paper presents a new method for designing orthonormal wavelet filter banks using the Remez exchange algorithm. It is well known that orthonormal wavelet bases can be generated by paraunitary filter banks. Thus, synthesis of orthonormal wavelet bases can be reduced to the design of paraunitary filter banks. From the orthonormality and regularity of wavelets, we derive some conditions that must be satisfied for FIR paraunitary filter banks, and investigate the relationship between the filter coefficients and their zeros. According to the relationship, we apply the Remez exchange algorithm in the z-domain directly and formulate the design problem in the form of a linear problem. Therefore, we can easily get a set of filter coefficients by solving the linear equations. Optimal solutions with an arbitrary regularity can be obtained after using an iteration procedure. In the proposed method, the main advantage is that less computational complexity is required as compared with the conventional methods. (C) 1998 Scripta Technica.
Scientific journal, English

Design for stable IIR perfect reconstruction filter banks using allpass filters
Zhang, X; T Yoshikawa
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS, SCRIPTA TECHNICA-JOHN WILEY & SONS, 81, 5, 24-32, May 1998, Peer-reviwed, This paper presents a new method for designing two-channel IIR linear phase filter banks that satisfy both the perfect reconstruction and stability conditions, using allpass filters. Using the perfect reconstruction condition for filter banks, we first offer a class of structurally perfect reconstruction implementations. Since the proposed filter banks must satisfy the perfect reconstruction condition even though the filter coefficients are quantized, the design problem becomes the design of half-band filters using a delay section and an allpass filter. Therefore, stable IIR perfect reconstruction filter banks can be easily obtained by approximating the phase responses of just the allpass filters. From the viewpoint of wavelets, a new method is presented for designing half-band filters with arbitrary flatness based on the parallel connection between the delay section and the allpass filter. Furthermore, by using two different allpass filters in the filter banks, the magnitude responses of low- and high-pass filters can be designed arbitrarily. (C) 1998 Scripta Technica.
Scientific journal, English

全域通過回路を用いた安定な IIR 完全再構成フィルタバンクの設計
張煕; 吉川敏則
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J81-A, 1, 24-32, Jan. 1998, Peer-reviwed, 本論文では, 全域通過回路を用いて, 完全再構成条件と安定条件を同時に満たす2チャネルIIR直線位相フィルタバンクの新しい設計法を提案する。まず, フィルタバンクの完全再構成条件から, 構造上完全再構成条件を満たす一つのフィルタ構成を示す。このフィルタ構成では, 係数量子化にもかかわらず, 完全再構成条件が必ず満たされるので, フィルタバンクの設計問題は遅延器と全域通過回路によるハーフバンドフィルタの設計になる。よって, 構成要素である全域通過回路の位相特性のみを近似すれば, 安定なIIR完全再構成フィルタバンクが容易に得られる。遅延器と全域通過回路を並列接続したIIRハーフバンドフィルタの設計に関しては, ウェーブレットの観点から, 平たん条件が任意に指定できるハーフバンドフィルタの設計法を提案する。また, フィルクバンクに二つの異なる全域通過回路を用いることで, 低域と高域フィルタの振幅特性を自由に設計できるのは本設計法の特長である。
Scientific journal, Japanese

構造上完全再構成双直交 FIR 直線位相フィルタバンクの設計
張煕; 吉川敏則
電子情報通信学会論文誌(A), J81-A, 1, 17-23, Jan. 1998, Peer-reviwed
Scientific journal, Japanese

Design of causal IIR perfect reconstruction filter banks
Zhang, X; T Yoshikawa
PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING, VOLS 1-6, IEEE, 1429-1432, 1998, Peer-reviwed, This paper presents a new method for designing two channel biorthogonal IIR filter banks, which satisfy both the perfect reconstruction and causal stable conditions. The proposed method is based on the formulation of a generalized eigenvalue problem by using Remez multiple exchange algorithm. Therefore, the filter coefficients can be computed by solving the eigenvalue problem, and the optimal solution is easily obtained through a few iterations. One example is designed to demonstrate the effectiveness of the proposed method.
International conference proceedings, English

Design of two channel IIR linear phase PR filter banks
Zhang, X; T Yoshikawa
ICSP '98: 1998 FOURTH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING, PROCEEDINGS, VOLS I AND II, IEEE, 11-14, 1998, Peer-reviwed, This paper proposes a novel method for designing two-channel biorthogonal perfect reconstruction (PR) filter banks with exact linear phase using IIR filters. Since the structurally PR implementation is adopted, the proposed filter banks are guaranteed to be PR even when all filter coefficients are quantized. From the Viewpoint of wavelets, design of IIR linear phase filter banks with an additional flatness condition is considered. The proposed design method is based on the formulation of a generalized eigenvalue problem by using Remez exchange algorithm. Therefore, the filter coefficients can be obtained by solving the eigenvalue problem, and the optimal solution with an equiriple magnitude response is easily obtained through a few iterations. The proposed procedure is computationally efficient, and the flatness condition can be arbitrarily specified.
International conference proceedings, English

Remez アルゴリズムによる直交ウェーブレットフィルタバンクの設計
張煕; 吉川敏則
電子情報通信学会論文誌(A), J80-A, 9, 1396-1402, Sep. 1997, Peer-reviwed
Scientific journal, Japanese

Recursive orthonormal wavelet bases with vanishing moments
Zhang, X; T Yoshikawa; H Iwakura
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E80A, 8, 1472-1477, Aug. 1997, Peer-reviwed, This paper presents a new method for constructing orthonormal wavelet bases with vanishing moments based on general IIR filters. It is well-known that orthonormal wavelet bases can be generated by paraunitary filter banks. Then, synthesis of orthonormal wavelet bases can be reduced to design of paraunitary filter banks. From the orthonormality and regularity of wavelets, we derive some constraints to IIR filter banks, and investigate relations between the constrained filter coefficients and its zeros and poles. According to these relations, we can apply Remez exchange algorithm in stopband directly and formulate the design problem in the form of an eigenvalue problem. Therefore, a set of filter coefficients can be easily computed by solving the eigenvalue problem, and the optimal filter coefficients with an equiripple response can be obtained after applying an iteration procedure. The proposed procedure is computationally efficient, and the number of vanishing moments can be arbitrarily specified.
Scientific journal, English

Design of FIR Nyquist filters using the Remez exchange algorithm
Zhang, X; H Iwakura
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA-JOHN WILEY & SONS, 80, 6, 22-29, Jun. 1997, Peer-reviwed, In this paper, we propose a method of designing FIR Nyquist filters with zero intersymbol interference by using the Remez exchange algorithm directly First, we present some magnitude properties of FIR Nyquist filters with zero intersymbol interference. It is known from the time-domain condition of zero intersymbol interference that the magnitude response of Nyquist filters in the passband is mainly dependent on the stopband magnitude. Therefore, the design problem of Nyquist filters becomes optimization of the magnitude response in the stopband. By using the Remez exchange algorithm in the stopband directly, we formulate the design problem in the form of a linear problem. The filter coefficients can be computed by simply solving the linear equations, and the optimal coefficients with equiripple stopband response are easily obtained after a few iterations. The proposed procedure is computationally more efficient than the existing procedures. Finally, we extend the proposed procedure to the design of matched Nyquist filter pairs, multistage Nyquist filters, and so on, Some design examples are presented to demonstrate the effectiveness of the proposed procedure. (C) 1997 Scripta Technica, Inc.
Scientific journal, English

Design of zero phase IIR Nyquist filters
Zhang, X; T Yoshikawa
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 33, 6, 469-470, Mar. 1997, Peer-reviwed, A new method for designing zero phase IIR Nyquist filters with zero intersymbol interference is presented. The proposed method is based on the eigenvalue problem by using the Remez exchange algorithm in the stopband, and the optimal filter coefficients can be easily obtained by computing the absolute minimum eigenvector and applying an iteration procedure.
Scientific journal, English

Design of FIR nyquist filters with low group delay
Xi Zhang; Toshinori Yoshikawa
IEEE Transactions on Signal Processing, 45, 7, 1902, 1997, A new method is proposed for designing FIR Nyquist filters with zero intersymbol interference (ISI) and low group delay. It is first shown that FIR Nyquist filters that satisfy the time-domain condition of zero ISI have a property on frequency response where both the magnitude and phase responses in the passband are dependent on the stopband response. Then, the design problem becomes an approximation of the magnitude response in the stopband only. The proposed procedure is based on the formulation of a linear problem by using the multiple Reniez exchange algorithm in the stopband directly. Therefore, the filter coefficients can be computed by solving the linear equations, and the optimal solution with an equiripple stopband response is easily obtained after applying an iteration procedure. Although the proposed Nyquist filters have an approximate linear phase response only, its group delay can be designed lower than the conventional FIR Nyquist filters with an exact linear phase. The proposed procedure is computationally efficient because it has been reduced to the computation of the linear equations. Finally, the characteristics of FIR Nyquist filters with low group delay are examined, and the performance is compared with the exact linear-phase FIR Nyquist filters through some design examples.
Scientific journal, English

Remez アルゴリズムによる FIR ナイキストフィルタの設計
張煕,岩倉博
電子情報通信学会論文誌(A), J79-A, 8, 1378-1384, Aug. 1996, Peer-reviwed
Scientific journal, Japanese

Design of IIR Nyquist filters with zero intersymbol interference
Zhang, X; H Iwakura
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E79A, 8, 1139-1144, Aug. 1996, Peer-reviwed, This paper presents a new method for designing IIR Nyquist filters with zero intersymbol interference. It is shown that IIR Nyquist filters with zero intersymbol interference have some constraints on frequency response, i.e., both magnitude and phase error in passband are dependent on stopband error. Therefore, the frequency response is required to optimize only in stopband. The proposed procedure is based on the formulation of an eigenvalue problem by using Remez multiple exchange algorithm in stopband. Then, the filter coefficients can be computed by solving the eigenvalue problem, and the optimal solution with equiripple stopband response is easily obtained by applying an iteration procedure. The proposed procedure is more computationally efficient than the conventional methods.
Scientific journal, English

Design of IIR digital filters based on eigenvalue problem
Zhang, X; H Iwakura
IEEE TRANSACTIONS ON SIGNAL PROCESSING, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 44, 6, 1325-1333, Jun. 1996, Peer-reviwed, This paper presents a new method for designing IIR digital filters with optimum magnitude response in the Chebyshev sense and different order numerator and denominator. The proposed procedure is based on the formulation of a generalized eigenvalue problem by using Remez exchange algorithm. Since there exist more than one eigenvalue in the general eigenvalue problem, we introduce a very simple selection rule for the eigenvalue to be sought for where the rational interpolation is performed if and only if the positive minimum eigenvalue is chosen. Therefore, the solution of the rational interpolation problem can be obtained by computing only one eigenvector corresponding to the positive minimum eigenvalue, and the optimal filter coefficients are easily obtained through a few iterations, The design algorithm proposed in this paper not only retains the speed inherent in the Remez exchange algorithm but also simplifies the interpolation step because it has been reduced to the computation of the positive minimum eigenvalue. Some properties of the filters such as lowpass filters, bandpass filters, and so on are discussed, and several design examples are presented to demonstrate the effectiveness of this method.
Scientific journal, English

Design of linear-phase IIR digital filters based on eigenvalue problem
Zhang, X; H Iwakura
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E79A, 4, 614-620, Apr. 1996, Peer-reviwed, It is known that an anticausal IIR filter can be realized in real time by using the time reversed section technique. When combined with a causal IIR filter, the overall transfer function can yield exact linear phase characteristic in theory. This paper presents a new method for designing complex IIR digital filters with exact linear phase. The design problem of IIR filters with exact linear phase can be reduced to magnitude-only filter design. The proposed procedure is based on the formulation of an eigenvalue problem by using Remez exchange algorithm. By solving the eigenvalue problem to compute the real maximum eigenvalue, the solution of the rational interpolation problem can be achieved. Therefore, the optimal filter coefficients are easily obtained through a few iterations. The proposed design algorithm not only retains the speed inherent in Remez exchange algorithm, but also simplifies the interpolation step because it has been reduced to the computation of the real maximum eigenvalue. Several examples are presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

複素全域通過回路を用いた QMF バンクの設計
張煕,岩倉博
電気通信大学紀要, 電気通信大学, 8, 2, 179-185, Dec. 1995, Peer-reviwed
Research institution, Japanese

EQUIRIPPLE DESIGN OF QMF BANKS USING DIGITAL ALLPASS NETWORKS
ZHANG, X; H IWAKURA
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E78A, 8, 1010-1016, Aug. 1995, Peer-reviwed, In this paper, we discuss design of quadrature mirror filter (QMF) banks using digital allpass networks in the frequency domain. In the QMF banks composed of a parallel connection of two allpass networks, both aliasing error and amplitude distortion are always completely canceled. Therefore, we only need to design the analysis filters and eliminate phase distortion of the overall transfer function. We consider design of the QMF banks in two cases where phase responses of the filters are required or not required. In the case where the phase responses are not required, the design problem can be reduced to design of phase difference of two allpass networks. In the case where the phase responses are required, we present a procedure for designing the QMF banks with both equiripple magnitude and phase responses.
Scientific journal, English

DESIGN OF DISCRETE COEFFICIENT FIR LINEAR-PHASE FILTERS USING HOPFIELD NEURAL NETWORKS
ZHANG, X; H IWAKURA
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E78A, 8, 900-904, Aug. 1995, Peer-reviwed, A novel method is presented for designing discrete coefficient FIR linear phase filters using Hopfield neural networks. The proposed method is based on the minimization of the energy function of Hopfield neural networks. In the proposed method, the optimal solution for each filter gain factor is first searched for, then the optimal filter gain factor is selected. Therefore, a good solution in the specified criterion can be obtained. The feature of the proposed method is that it can be used to design FIR linear phase filters with different criterions simultaneously. A design example is presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

Design of digital allpass functions with specified phase tolerances
Zhang, X; H Iwakura
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA PUBL, 78, 8, 1-9, Aug. 1995, Peer-reviwed, In this paper, a new method is introduced for designing IIR digital allpass functions with specified phase tolerances. Since the phase error characteristics subject to the desired phase response have been specified in the interest bands, the phase design of digital allpass functions in the form of a linear programming problem can be formulated by using the Remez exchange algorithm. Then the linear equations are solved to obtain a set of filter coefficients and the optimal coefficients in the Chebyshev sense can easily be obtained through a few iterations. By appropriately selecting the initial extremal frequencies, the proposed design algorithm always converges, and the phase error characteristics can be arbitrarily specified. Finally, some design examples are presented to demonstrate the effectiveness of the proposed method.
Scientific journal, English

指定位相誤差特性を有するディジタル全域通過関数の設計
張煕,岩倉博
電子情報通信学会論文誌(A), J78-A, 3, 349-356, Mar. 1995, Peer-reviwed
Scientific journal, Japanese

DESIGN OF QMF BANKS USING ALLPASS FILTERS
ZHANG, X; H IWAKURA
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 31, 3, 172-174, Feb. 1995, Peer-reviwed, The authors consider the design of quadrature mirror filter (QMF) banks using digital allpass filters. The QMF banks consisting of an allpass filter and a pure delay section have an approximately linear phase response, and the phase distortion can be minimised by using another additional allpass filter as an equaliser.
Scientific journal, English

Design of FIR Linear Phase Filters with Discrete Coefficients Using Hopfield Neural Networks
X.Zhang; H.Iwakura
Proceedings of ISPACS 1994, P3.12, Oct. 1994, Peer-reviwed
International conference proceedings, English

DESIGN OF FIR LINEAR-PHASE FILTERS WITH DISCRETE COEFFICIENTS USING HOPFIELD NEURAL NETWORKS
ZHANG, X; H IWAKURA
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 30, 13, 1039-1040, Jun. 1994, Peer-reviwed, A novel method is presented for designing FIR linear phase filters with discrete coefficients using Hopfield neural networks. The proposed procedure is based on the minimisation of the energy function of the Hopfield neural network, and can produce a good solution to the design of FIR linear phase filters with discrete coefficients.
Scientific journal, English

DESIGN OF DIGITAL ALLPASS NETWORKS BASED ON THE EIGENVALUE PROBLEM
ZHANG, X; H IWAKURA
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE, SCRIPTA TECHNICA PUBL, 77, 4, 99-109, Apr. 1994, Peer-reviwed, This paper presents a new method of the phase design for the digital allpass network utilizing the eigenvalue problem. The proposed design method considers the phase error between the phase response of the allpass network to be realized and the ideal phase response. The design problem is formulated as an eigenvalue problem based on the Remez algorithm. By calculating the eigenvector corresponding to the maximum eigenvalue, the filter coefficients are determined and the optimal approximate solution is obtained by iterative calculation.
In the design method, the eigenvector corresponding to the maximum eigenvalue is calculated to determine the filter coefficients so that the phase error is minimized. Consequently, the convergence of the design algorithm is guaranteed. Usually, the optimal approximate solution is obtained by several times of iterations. The error-ratio of the phase characteristics can be set arbitrarily, and the stability of the filter is ensured.
Finally, the method is extended to the phase design for the digital allpass network with complex coefficients, several design examples are shown, and the usefulness of the proposed design method is demonstrated.
Scientific journal, English

固有値問題に基づいたディジタル全域通過回路の設計
張煕,岩倉博
電子情報通信学会論文誌(A), The Institute of Electronics, Information and Communication Engineers, J76-A, 12, 1675-1683, Dec. 1993, Peer-reviwed, 本論文では,固有値問題に基づいたディジタル全域通過回路の新しい位相設計法を提案する.本設計法では,設計する全域通過回路の位相特性と理想位相特性との位相誤差に着目し,Remezアルゴリズムを用いて,設計問題を固有値問題の形で定式化する.その最大固有値に対応する固有値ベクトルを計算してフィルタ係数を求め,更に反復計算を行い最適近似解を得ている.本設計法では,最大固有値ベクトルを計算し,位相誤差が最小となるフィルタ係数を求めているので,設計アルゴリズムの収束性が必ず保証される.通常,数回の繰返しで最適近似解が得られ,位相特性の誤差比を任意に与えることができ,かつフィルタの安定性が必ず保証される.最後に,複素係数をもつディジタル全域通過回路の位相設計への拡張を示す.いくつかの例題を設計し,本設計法の有効性を示す.
Scientific journal, Japanese

NOVEL METHOD FOR DESIGNING DIGITAL ALLPASS FILTERS BASED ON EIGENVALUE PROBLEM
ZHANG, X; H IWAKURA
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 29, 14, 1279-1281, Jul. 1993, Peer-reviwed, A novel method is presented for designing digital allpass filters with equiripple phase responses based on the eigen-value problem, and shows that the optimal filter coefficient, can be easily obtained by computing the maximum eigen-vector and applying an iteration procedure.
Scientific journal, English

相反回路を基本としたウェーブディジタルラティスフィルタの構成
張煕,岩倉博
電子情報通信学会論文誌(A), J76-A, 3, 312-320, Mar. 1993, Peer-reviwed
Scientific journal, Japanese

Design of IIR digital filters with given magnitude specifications using allpass networks
Xi Zhang; Hiroshi Iwakura
Electronics and Communications in Japan (Part III: Fundamental Electronic Science), 76, 3, 45-56, 1993, Peer-reviwed, This paper proposes a direct design method in the z‐domain for the IIR digital filter with a parallel structure composed of allpass networks with complex and real coefficients, with the specifications for the bandedge frequencies of the passband and stopband as well as the magnitude in the passband (or stopband). First, a filter composed of two allpass networks with conjugate complex coefficients is considered. Also, the phase difference characteristic between the two networks is considered. By specifying the phase difference error, the determination of the filter coefficients is reduced to the eigenvalue problem of the matrix using Remez' algorithm. The filter coefficients are determined from the eigenvector corresponding to the maximum eigenvalue. Then iterative calculation is executed to realize the equiripple characteristic, and the optimal solution is derived. Next, the relation between the phase difference errors and the magnitude errors is discussed and it is shown that the filter can be designed by the proposed method by specifying the absolute value of the magnitude error. The usefulness of the proposed method is shown by design examples. The filter based on two allpass networks with real coefficients is also considered, and it is shown that the filter can be designed by the same procedure by formulating the procedure for the sum and the difference of the filter coefficients. Copyright © 1993 Wiley Periodicals, Inc., A Wiley Company
Scientific journal, English

全域通過回路による指定誤差特性を有するIIRディジタルフィルタの設計
張煕,岩倉博
電子情報通信学会論文誌(A), 電子情報通信学会基礎・境界ソサイエティ, J75-A, 7, 1155-1163, Jul. 1992, Peer-reviwed
Scientific journal, Japanese

指定誤差特性を有するFIRディジタルフィルタの設計 --- ニューラルネットによる解法
張煕,岩倉博
電子情報通信学会論文誌(A), J75-A, 3, 526-533, Mar. 1992, Peer-reviwed
Scientific journal, Japanese

全域通過回路によるコンプリメンタリ型IIRディジタルフィルタの設計 --- 最大固有値問題による設計法
張煕,岩倉博
電子情報通信学会論文誌(A), J75-A, 3, 491-499, Mar. 1992, Peer-reviwed
Scientific journal, Japanese

DESIGN OF IIR DIGITAL-FILTERS USING COMPLEX ALLPASS NETWORK BASED ON EIGENVALUE PROBLEM
ZHANG, X; H IWAKURA
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 28, 3, 231-233, Jan. 1992, Peer-reviwed, A new design method is presented for complementary IIR digital filters with given magnitude specifications based on the eigenvalue problem, which are composed of a single complex allpass section.
Scientific journal, English

Design of FIR digital filters with specified tolerances—A neural network approach
Xi Zhang; Hiroshi Iwakura
Electronics and Communications in Japan (Part III: Fundamental Electronic Science), 75, 12, 1-10, 1992, Peer-reviwed, This paper presents a design method for the equal‐ripple, linear‐phase FIR digital filter when the tolerance for the error of magnitude response in the passband or stopband is specified. To realize the design when various constraints are imposed on the transfer function or magnitude response, the design problem is formulated as the optimization problem. A solution method is shown to solve the problem using the constrained neural net. When the lower bound of the magnitude error in the stopband is set as zero in the proposed method, the filter with double zeros in the stopband can easily be designed. Examples of application are shown for the minimum‐phase FIR filter and the matched filter pair with zero intersymbol interference. Copyright © 1992 Wiley Periodicals, Inc., A Wiley Company
Scientific journal, English

制約条件を有する最小２乗近似直線位相FIRフィルタの設計
張煕,岩倉博
電気通信大学紀要, The University of Electro-Communications, 4, 2, 225-233, Dec. 1991, Peer-reviwed
Scientific journal, Japanese

TDMA拡譜通信系統中精同歩的実現与性能分析
李京棋; 周鳳鳴,張煕
南京航空学院学報, 93-103, 1984, Peer-reviwed
Research institution, Japanese

Quincunx Wavelet Image Coding Using 2D Allpass Filters
SUDO Osamu; ZHANG Xi
JPEG2000 is the most successful wavelet-based image compression standard. D-9/7 wavelet used in JPEG2000 is redundant because it is biorthogonal. Therefore, wavelet filter banks using allpass filters that satisfy both orthogonality and perfect linear phase have been proposed and shown superior compression performance. However, the wavelets employ separable filter banks, resulting in poor visual quality. In this paper, we propose non-separable quincunx wavelet filter banks using 2D allpass filters to perform better image quality. Furthermore, we compare the results with D-9/7 wavelet and conventional method to demonstrate the efficiency of the proposed method., The Institute of Electronics, Information and Communication Engineers, 15 Dec. 2011, IEICE technical report. Image engineering, 111, 349, 87-92, Japanese, 0913-5685, 110009466724, AN10013006

Lossy to Lossless Image Coding Using Allpass Filters
OHNO Kosuke; ZHANG Xi
To obtain a better coding performance in wavelet-based image compression, it is necessary for wavelet filter banks to satisfy the orthogonality condition and linear phase characteristic. To satisfy these conditions, a class of IIR wavelet filters have been proposed by using allpass filters, and then a better coding performance has been obtained for lossy image coding. In this paper, we propose an effective implementation of reversible wavelet transform by using allpass filters. This method needs to transfer the side information that is used to start IIR filtering. We give a technique transfering these data efficiently. The experimental results show that the proposed wavelet filters are better than the conventional wavelets in both lossless and lossy performance., Information Processing Society of Japan (IPSJ), 27 Oct. 2006, 情報処理学会研究報告システムLSI設計技術（SLDM）, 2006, 111, 183-188, Japanese, 0919-6072, 110004839530, AA11451459

全域通過回路によるコンプリメンタリIIR直線位相フィルタの設計
張熙
1991, 信学技報, CAS91-25, 10006736608, AN00245490

ニューラルネットによる FIR ディジタルフィルタの設計
張煕
1989, 信学技報, CAS89-105, 10006926449, AN00245490

Wavelet Theory
Xi Zhang e
Scholarly book, English, Joint work, Wavelet Filter Banks Using Allpass Filters, IntechOpen, 30 Nov. 2020

Foundations of Digital Signal Processing
Shimada, Yasukawa; Itoh, Taguchi; Zhang, Iwahashi
Textbook, Japanese, Joint work, 第７章 応用, CORONA Publishing Co., LTD., 16 Jun. 2006

HDR Image Coding Based on Multiple Exposure LDR Images
S.Muromoto; X.Zhang
Poster presentation, English, The 6th ASEAN UEC Workshop 2024, Peer-reviewed
08 Sep. 2024
07 Sep. 2024- 08 Sep. 2024

Motion Compensation in Wavelet Video Coding Using Graph Signal Processing
T.Kanno; X.Zhang
Poster presentation, English, The 6th ASEAN UEC Workshop 2024, Peer-reviewed
08 Sep. 2024
07 Sep. 2024- 08 Sep. 2024

奇数次線形位相FIRフィルタによる完全再構成グラフフィルタバンクの設計
徳永朱香; 張煕
Oral presentation, Japanese, 第37回信号処理シンポジウム, IEICE, 新潟, Domestic conference
15 Dec. 2022

グラフウェーブレットフィルタバンクによる画像処理のためのグラフ作成について
斎藤翔太; 張煕
Oral presentation, Japanese, 第37回信号処理シンポジウム, IEICE, 新潟, Domestic conference
15 Dec. 2022

動き領域をもつ多重露光画像合成における画質改善
市田涼香; 張煕
Oral presentation, Japanese, 第37回信号処理シンポジウム, IEICE, 新潟, Domestic conference
13 Dec. 2022

HDR Image Composition Using Undecimated Discrete Wavelet Transform
H. Morozumi; X. Zhang
Poster presentation, English, The 3rd ASEAN-UEC Workshop on Informatics and Engineering for SDGs, 2021, ECTI, UEC, On line, International conference
10 Dec. 2021

Reducing Residual Frame Information In Wavelet Video Coding Using Bandlet Transform
R. Kato; X. Zhang
Poster presentation, English, The 3rd ASEAN-UEC Workshop on Informatics and Engineering for SDGs, 2021, ECTI, UEC, On line, International conference
10 Dec. 2021

Compression Performance of Sampling Patterns Suitable for Image Edges
K. Kawai; X. Zhang
Poster presentation, English, The Irago Conference 2020, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
10 Dec. 2020

Improvement of Weight Generation in Frame Interpolation of Videos
H. Morozumi; X. Zhang
Poster presentation, English, The Irago Conference 2020, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
10 Dec. 2020

Blood Vessels Segmentation for Fundus Images Using Machine Learning and Image Pre-processing
S. Uchiyama; X. Zhang
Poster presentation, English, The Irago Conference 2020, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
10 Dec. 2020

Improvement of Spatial Transform for Residual Frame in Wavelet Video Coding using Block Matching
R. Kato; X. Zhang
Poster presentation, English, The Irago Conference 2020, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
10 Dec. 2020

Threshold Estimation of Wavelet Shrinkage Using Fuzzy Theory for Flicker Reduction of Motion JPEG 2000
Y. Kitajima; X. Zhang
Poster presentation, English, The Irago Conference 2020, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
10 Dec. 2020

HOG特徴量とガボールフィルタを用いた眼底画像の血管抽出
内山蒼介; 張煕
Oral presentation, Japanese, 電子情報通信学会総合大会, 電子情報通信学会, 広島, Domestic conference
19 Mar. 2020

Blood Vessels Segmentation Algorithm for Fundus Images
S. Uchiyama; X. Zhang
Poster presentation, English, The Irago Conference 2019, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
29 Oct. 2019

Threshold Estimation of Wavelet Shrinkage Using Median Filter for Flicker Reduction of H.264/AVC
Y. Kitajima; X. Zhang
Poster presentation, English, The Irago Conference 2019, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
29 Oct. 2019

Image Compression Via Adaptive Triangulation Approximation Using Feature Points
C. Y. Ge; X. Zhang
Poster presentation, English, The Irago Conference 2019, EIIRIS, TUT, UEC, Chofu, Tokyo, Japan, International conference
29 Oct. 2019

Low Light Image Enhancement Using Gamma Correction-Incorporated Retinex Model
S. Wu; X. Zhang
Poster presentation, English, The Irago Conference 2018, EIIRIS, TUT, UEC, Shinjuku, Tokyo, Japan, International conference
01 Nov. 2018

Improvement of Region Weight Generation Method for Frame Interpolation
T. Matsuura; X. Zhang
Poster presentation, English, The Irago Conference 2018, EIIRIS, TUT, UEC, Shinjuku, Tokyo, Japan, International conference
01 Nov. 2018

Edge-aware Graph Wavelet Transform for Image Compression
H. Ebisuyu; X. Zhang
Poster presentation, English, The Irago Conference 2018, EIIRIS, TUT, UEC, Shinjuku, Tokyo, Japan, International conference
01 Nov. 2018

Improvement of Frame Interpolation with Trajectories of Feature Points
S. Hirasawa; X. Zhang
Poster presentation, English, The Irago Conference 2018, EIIRIS, TUT, UEC, Shinjuku, Tokyo, Japan, International conference
01 Nov. 2018

Image Fusion and IoT
X.Zhang; A.Miyagawa
Nominated symposium, Japanese, 第9回横幹連合コンファレンス, Invited, Domestic conference
06 Oct. 2018

Image Fusion and IoT
X.Zhang; A.Miyagawa
Nominated symposium, Japanese, 第9回横幹連合コンファレンス, Invited, 東京, Domestic conference
06 Oct. 2018

Improvement of Hierarchical Motion Compensation in 2D+t Wavelet Scalable Video Coding
H. Hamada; X. Zhang
Poster presentation, English, The Irago Conference 2017, EIIRIS, TUT, UEC, Chofu-city, Tokyo, Japan, International conference
01 Nov. 2017

HDR Imaging from LDR Images with Motion by Estimating Shutter Speed
A. Miyagawa; X. Zhang
Poster presentation, English, The Irago Conference 2017, EIIRIS, TUT, UEC, Chofu-city, Tokyo, Japan, International conference
01 Nov. 2017

Design of Two Channel Graph Filter Banks from Linear Phase FIR Filters
S. Matsunaga; X. Zhang
Poster presentation, English, The Irago Conference 2017, EIIRIS, TUT, UEC, Chofu-city, Tokyo, Japan, International conference
01 Nov. 2017

相対シャッタースピード推定による動きを含むHDR画像合成
宮川愛加; 張煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告、信号処理研究会, 電子情報通信学会信号処理研究会, 東京, Domestic conference
24 Aug. 2017

オールパスフィルタに基づくウェーブレットによる高精細圧縮動画像のフリッカー低減
志賀洋介; 張煕
Oral presentation, Japanese, 第31回信号処理シンポジウム, IEICE, 大阪, Domestic conference
08 Nov. 2016

High Dynamic Range Image Compression Using Improved Logarithmic Transformation
M.Sumizawa; X. Zhang
Poster presentation, English, The Irago Conference 2016, EIIRIS, TUT, UEC, Chofu-city, Tokyo, Japan, International conference
01 Nov. 2016

Frame Interpolation Method for Low Frame Rate Videos
K.Yoshida; X. Zhang
Poster presentation, English, The Irago Conference 2016, EIIRIS, TUT, UEC, Chofu-city, Tokyo, Japan, International conference
01 Nov. 2016

Improvement of Search Algorithm for Motion Compensation in Video Coding
J.Gao; X. Zhang
Poster presentation, English, The Irago Conference 2016, EIIRIS, TUT, UEC, Chofu-city, Tokyo, Japan, International conference
01 Nov. 2016

対数変換を改良したHDR画像符号化
住澤柾秀; 張煕
Oral presentation, Japanese, 電子情報通信学会総合大会, 電子情報通信学会, 九州, Domestic conference
18 Mar. 2016

ヒストグラムパッキングを用いたHDR画像二階層符号化の改善
菅野元貴; 張煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告、画像工学研究会, 電子情報通信学会画像工学研究会, 神戸, Domestic conference
04 Dec. 2015

Flicker Reduction for Motion JPEG 2000 Using Allpass-based Wavelets
Y. Shiga; X. Zhang
Poster presentation, English, The Irago Conference 2015, EIIRIS, TUT, UEC, Tahara-city, Aichi, Japan, International conference
23 Oct. 2015

MthバンドFIR線形位相フィルタの最適近似
張 煕
Public symposium, Japanese, 2014年電子情報通信学会ソサイエティ大会, 電子情報通信学会, 徳島, Domestic conference
25 Sep. 2014

Self-Tuned Auxiliary-Noise-Power Scheduling with Matching Step-Size for Online Acoustic Feedback Path Mitigation in Active Noise Control
S. Ahmed; M. T. Akhtar; X. Zhang
Oral presentation, English, 電子情報通信学会技術研究報告、電気／応用音響・聴覚・音楽音響研究会, 電子情報通信学会, 仙台, Domestic conference
19 Aug. 2014

2D+t型ウェーブレット動画像スケーラブル符号化の圧縮効率の改善
安岡諒,張煕
Public symposium, Japanese, 2013年度画像符号化シンポジウム(PCSJ 2013), 電子情報通信学会, 湯河原
Nov. 2013

2次元方向適応型ウェーブレット変換を用いた画像ロスレス符号化
鴻田峻,張煕
Public symposium, Japanese, 2013年度画像符号化シンポジウム(PCSJ 2013), 電子情報通信学会, 湯河原
Nov. 2013

Denoising of HDR Images Using correlation of LDR Images
Mizuhito Akiyama; Xi Zhang
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Aug. 2013

エイリアシング低減による3Dウェーブレット動画像符号化の低解像度再生時の画質改善
鈴木拓也; 張煕
Oral presentation, Japanese, 第14回DSPS教育会議
Sep. 2012

平坦群遅延特性を有するQ-shift FIRフィルタの設計
森原裕晶; 張煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告,画像工学研究会
Dec. 2011

オールパスフィルタを用いたキンカンクス画像ウェーブレット符号化
須藤修; 張煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告,画像工学研究会
Dec. 2011

3次元ウェーブレットを用いた動画像のスケーラブル符号化
小山田寛史; 張煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告,画像工学研究会
Dec. 2011

Design of DTCWT with Improved Analyticity and Frequency Selectivity
D.W.Wang; X.Zhang
Public symposium, English, 第26回信号処理シンポジウム, 電子情報通信学会
Nov. 2011

マルチスケール変換を用いた画像フュージョン
小林達也; 張煕
Public symposium, Japanese, 第26回信号処理シンポジウム, 電子情報通信学会
Nov. 2011

隣接情報を利用したMotion-JPEG2000のフリッカー低減
石野智晴; 張煕
Oral presentation, Japanese, 電子情報通信学会,2011年総合大会
Mar. 2011

複素チェビシェフ近似によるFIR分数微分フィルタの設計
鈴木敬彦; 張煕
Oral presentation, Japanese, 電子情報通信学会,2011年総合大会
Mar. 2011

リフティング構成による多方向選択性フィルタバンクの設計
福田和宏; 張煕
Oral presentation, Japanese, 電子情報通信学会,2011年総合大会
Mar. 2011

ウェーブレット縮退法を用いたMotion JPEG 2000のフリッカー低減
田中敦; 張煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告,画像工学研究会
Dec. 2009

Closed--Form Design of Maxflat Fractional Delay IIR Filters
Xi Zhang
Oral presentation, English, 2008年電子情報通信学会総合大会
Mar. 2008

2次元非分離型オールパスフィルタを用いたロスレス画像圧縮",
大野弘祐; 張 煕
Oral presentation, Japanese, 2008年電子情報通信学会総合大会
Mar. 2008

オールパスフィルタによる画像圧縮における演算量の低減
大野弘祐; 張 煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告,信号処理研究会
Oct. 2007

Closed-Form Design of Maxflat R-Regular IIR Mth-Band Filters
Xi Zhang
Oral presentation, English, 電子情報通信学会,2007年総合大会
Mar. 2007

オールパスフィルタを用いた画像ロシー・ロスレス符号化
大野弘祐; 張 煕
Oral presentation, Japanese, 電子情報通信学会技術研究報告,信号処理研究会
Oct. 2006

Hilbert Transform Pairs of Orthonormal Symmetric Wavelet Bases Using Allpass Filters
Xi Zhang
Oral presentation, English, 2006年電子情報通信学会ソサイエティ大会
Sep. 2006

複素全域通過フィルタによるロスレス画像ウェーブレット符号化
福田法旦; 張煕; 吉川敏則; 武井由智; 杉田泰則
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Sep. 2005

IIRフィルタを用いたウェーブレット基底のヒルベルト変換対の設計
河田邦洋; 張煕; 吉川敏則; 武井由智; 杉田泰則
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Sep. 2005

平坦群遅延特性を有する逆チェビシェフ型IIRフィルタの設計
相澤正智; 張煕; 吉川敏則; 武井由智; 杉田泰則
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Sep. 2005

複素全域通過フィルタによるロスレス画像ウェーブレット符号化
福田法旦; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2005年電子情報通信学会総合大会
Mar. 2005

平坦群遅延特性を有する逆チェビシェフ型IIRフィルタの設計
相澤正智; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2005年電子情報通信学会総合大会
Mar. 2005

オールパスフィルタによるロスレス画像ウェーブレット符号化
川井宏亮; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 第47回 自動制御連合講演会
Nov. 2004

IIRフィルタを用いたウェーブレット基底のヒルベルト変換対の設計
河田邦洋; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 第47回 自動制御連合講演会
Nov. 2004

2次元疎フーリエ表現推定アルゴリズムの処理効率に関する検討
西村和隆; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 平成16年度電子情報通信学会信越支部大会
Oct. 2004

公開検証可能秘密分散法の多人数協力計算への応用に関する検討
奥崎徳仁; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 平成16年度電子情報通信学会信越支部大会
Oct. 2004

On the Error in the Stopband of Mth Band Maxflat FIR Filters
L.A.Pe; T.Yoshikawa; Y.Takei; X.Zhang
Oral presentation, Japanese, 平成16年度電子情報通信学会信越支部大会
Oct. 2004

疎フーリエ表現に対するサンプリングアルゴリズムの2次元への拡張
西村和隆; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 2004年電子情報通信学会総合大会
Mar. 2004

波形モーメントを用いた最大平坦 R-Regular FIR Mth-Band フィルタの解析的設計法
小林大輔; 和田達矢; 張煕; 吉川敏則; 武井由智
Public symposium, Japanese, 第18回ディジタル信号処理シンポジウム, 第18回ディジタル信号処理シンポジウム
Nov. 2003

逆数合同疑似乱数の双曲線構造の発生条件の実験的検討
本郷雄史; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 平成15年度電子情報通信学会信越支部大会
Oct. 2003

オールパスフィルタを用いた画像ロスレス圧縮
川井宏亮; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成15年度電子情報通信学会信越支部大会
Oct. 2003

Inversive Congruential Pseudorandom Numbers の双曲線構造について
本郷雄史; 武井由智; 吉川敏則; 張煕
Public symposium, Japanese, NOCシンポジウム, NOCシンポジウム
Jul. 2003

リフティング構成を用いたIIR直交フィルタバンクの設計と画像圧縮への応用
王緯,張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 映像情報メディア学会技術報告
Jun. 2003

波形モーメントによる任意遅延FIR最大平坦フィルタの設計
小林大輔; 吉川敏則; 張煕; 武井由智
Oral presentation, Japanese, 2003年電子情報通信学会総合大会
Mar. 2003

R-Regular FIR Mth-Bandフィルタの解析解
和田達矢; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2003年電子情報通信学会総合大会
Mar. 2003

平坦群遅延特性を有するIIRバターワースフィルタの設計
永嶋玄太郎; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2003年電子情報通信学会総合大会
Mar. 2003

IIR直交フィルタバンクのリフティング実現法
王緯,張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2003年電子情報通信学会総合大会
Mar. 2003

波形モーメントによる任意遅延最大平坦型FIRフィルタの設計
小林大輔; 吉川敏則; 張煕; 武井由智
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

R-Regular FIR Mth-Band フィルタの解析解
和田達矢; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

平坦群遅延特性を有するバターワース型IIRフィルタの設計
永嶋玄太郎; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

高速フーリエ変換のノイズ解析について
長谷川剛志; 吉川敏則; 張煕; 武井由智
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

画像圧縮性能へのフィルタ平坦度の影響について
野村直樹; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

IIR直交フィルタバンクのリフティング実現法
王緯,張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

量子計算が有効な部分和問題の例題についての検討
最上直史; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

Inversive Congruential Pseudorandom Numbers の双曲線構造について
本郷雄史; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 平成14年度電子情報通信学会信越支部大会
Oct. 2002

部分和問題のための量子回路の構成についての検討
最上直史; 武井由智; 吉川敏則; 張煕
Public symposium, Japanese, 2002年度LAシンポジウム, 2002年度LAシンポジウム
Jul. 2002

Inversive Congruential Pseudorandom Numbers の双曲線構造について
本郷雄史; 武井由智; 吉川敏則; 張煕
Public symposium, Japanese, 2002年度LAシンポジウム, 2002年度LAシンポジウム
Jul. 2002

SNR改善のためのFIR内挿フィルタの設計
茂木孝一; 吉川敏則; 張煕; 武井由智
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Jul. 2002

On Leapfrog Use of Inversive Linear Congruential Pseudorandom Generators
Y.Takei; T.Yoshikawa; X.Zhang
Public symposium, Japanese, 第5回ネットワークシンポジウム, 第5回ネットワークシンポジウム
Mar. 2002

The Braid Conjugacy Problem and Group Representations over Cyclotomic Fields
T.Shimizu; Y.Takei; T.Yoshikawa; X.Zhang
Oral presentation, Japanese, 2002年電子情報通信学会総合大会
Mar. 2002

部分和問題のための量子回路の構成についての検討
最上直史; 武井由智; 吉川敏則; 張煕
Oral presentation, Japanese, 2002年電子情報通信学会総合大会
Mar. 2002

On the Distribution of the Fractional Linear Pseudorandom Generator
Y.Takei; T.Yoshikawa; X.Zhang
Public symposium, Japanese, 2001年度LAシンポジウム, 2001年度LAシンポジウム
Feb. 2002

直線位相IIRフィルタバンクを用いた画像ロスレス符号化
阿部洋; 張煕; 吉川敏則; 武井由智
Public symposium, Japanese, 第16回ディジタル信号処理シンポジウム, 第16回ディジタル信号処理シンポジウム, 沖縄
Nov. 2001

チェビシェフ型IIR直線位相フィルタの設計
竹内良介; 張煕; 吉川敏則; 武井由智
Public symposium, Japanese, 第16回ディジタル信号処理シンポジウム, 第16回ディジタル信号処理シンポジウム, 沖縄
Nov. 2001

任意の平坦度を有するIIRハーフバンドフィルタの設計
山下亮; 張煕; 吉川敏則; 武井由智
Public symposium, Japanese, 第16回ディジタル信号処理シンポジウム, 第16回ディジタル信号処理シンポジウム, 沖縄
Nov. 2001

FIRディジタルフィルタの複素チェビシェフ近似
中山悟; 張煕; 吉川敏則; 武井由智
Public symposium, Japanese, 第16回ディジタル信号処理シンポジウム, 第16回ディジタル信号処理シンポジウム, 沖縄
Nov. 2001

A Possible Attack on Braid-based Public-key Cryptosystems
T.Shimizu; Y.Takei; T.Yoshikawa; X.Zhang
Oral presentation, Japanese, 平成13年度電子情報通信学会信越支部大会
Oct. 2001

FIRディジタルフィルタの複素チェビシェフ近似
中山悟; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成13年度電子情報通信学会信越支部大会
Oct. 2001

因果的安定なIIR DFTフィルタバンクの設計
本田和章; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成13年度電子情報通信学会信越支部大会
Oct. 2001

チェビシェフ型IIR直線位相フィルタの設計
竹内良介; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2001年電子情報通信学会総合大会
Mar. 2001

最大平坦IIRハーフバンドフィルタの設計
山下亮; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2001年電子情報通信学会総合大会
Mar. 2001

直線位相IIRフィルタバンクを用いた画像ロスレス符号化
阿部洋; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 2001年電子情報通信学会総合大会
Mar. 2001

遺伝的アルゴリズムを用いたプリフィルタ・イコライザの設計
上林俊也; 吉川敏則; 張煕; 武井由智
Oral presentation, Japanese, 平成12年度電子情報通信学会信越支部大会
Oct. 2000

通過域に任意の平坦度を有するIIR直線位相フィルタの設計
田村圭; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成12年度電子情報通信学会信越支部大会
Oct. 2000

近似的直線位相を有するIIRフィルタの設計
竹内良介; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成12年度電子情報通信学会信越支部大会
Oct. 2000

IIR最大平坦ハーフバンドフィルタの設計
山下亮; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成12年度電子情報通信学会信越支部大会
Oct. 2000

FIRディジタル微分器の設計
中山悟; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成12年度電子情報通信学会信越支部大会
Oct. 2000

IIRフィルタを用いた画像ロスレス符号化
阿部洋; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 平成12年度電子情報通信学会信越支部大会
Oct. 2000

複素全域通過フィルタを用いた画像ウェーブレット符号化
上村晴也; 張煕; 吉川敏則; 武井由智
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Sep. 2000

拡張波形モーメントを用いた線形位相FIRディジタルフィルタの一設計法
長門浩司; 吉川敏則; 張煕; 武井由智
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Sep. 2000

IIR型直線位相QMFバンクを用いた画像圧縮
上村晴也; 張煕; 吉川敏則
Oral presentation, Japanese, 第13回回路とシステム(軽井沢)ワークショップ, 第13回回路とシステム(軽井沢)ワークショップ, 軽井沢, Domestic conference
Apr. 2000

波形モーメントの拡張とFIRディジタルフィルタ設計への応用
長門浩司; 吉川敏則; 張煕
Oral presentation, Japanese, 第13回回路とシステム(軽井沢)ワークショップ, 第13回回路とシステム(軽井沢)ワークショップ, 軽井沢, Domestic conference
Apr. 2000

オールパスフィルタを用いた画像ウェーブレット符号化
上村晴也; 張煕; 吉川敏則
Public symposium, Japanese, 第2回DSPS教育者会議, 第2回DSPS教育者会議, 東京
Mar. 2000

遺伝的アルゴリズムに基づく教師つきテクスチャ分類用トレーニングエリアの自動選定
奥村浩; 内山克史; 梶原康司; 張煕; 吉川敏則
Public symposium, Japanese, 第2回CEReS環境リモートセンシングシンポジウム, 第2回CEReS環境リモートセンシングシンポジウム
Dec. 1999

複素全域通過関数を用いた直線位相QMFバンクの設計
加藤明,張煕; 吉川敏則
Public symposium, Japanese, 第14回ディジタル信号処理シンポジウム, 第14回ディジタル信号処理シンポジウム
Nov. 1999

固有値問題に基づいたIIRディジタルフィルタの複素チェビシェフ近似
鈴木一喜; 張煕; 吉川敏則
Public symposium, Japanese, 第14回ディジタル信号処理シンポジウム, 第14回ディジタル信号処理シンポジウム
Nov. 1999

遺伝的アルゴリズムを用いたプリフィルタ―イコライザの設計
上林俊也; 吉川敏則; 張煕
Oral presentation, Japanese, 平成11年度電子情報通信学会信越支部大会
Oct. 1999

通過域平坦阻止域等リプル特性を有するIIR直線位相フィルタの設計
田村圭,張煕; 吉川敏則
Oral presentation, Japanese, 平成11年度電子情報通信学会信越支部大会
Oct. 1999

波形モーメントの拡張とフィルタ設計への応用
長門浩司; 吉川敏則; 張煕,奥村浩
Oral presentation, Japanese, 平成11年度電子情報通信学会信越支部大会
Oct. 1999

IIR型直線位相QMFバンクを用いた画像圧縮
上村晴也; 張煕; 吉川敏則
Oral presentation, Japanese, 平成11年度電子情報通信学会信越支部大会
Oct. 1999

固有値問題に基づいたIIRフィルタの複素チェビシェフ近似
鈴木一喜; 張煕; 吉川敏則
Oral presentation, Japanese, 1999年電子情報通信学会総合大会
Mar. 1999

複素全域通過関数による直線位相QMFバンクの設計
加藤明,張煕; 吉川敏則
Oral presentation, Japanese, 1999年電子情報通信学会総合大会
Mar. 1999

空間周波数領域における回転不変モーメント量を用いるリモートセンシング画像の教師つきテクスチャ分類(II) --- テクスチャが混在した場合
内山克史; 成田常晃; 奥村浩,張煕; 吉川敏則
Oral presentation, Japanese, 1999年電子情報通信学会総合大会
Mar. 1999

空間周波数領域における回転不変モーメント量を用いるリモートセンシング画像の教師つきテクスチャ分類
奥村浩; 成田常晃; 梶原康司; 張煕; 吉川敏則
Public symposium, Japanese, 第1回CEReS環境リモートセンシングシンポジウム, 第1回CEReS環境リモートセンシングシンポジウム
Dec. 1998

任意の平坦度を有する低遅延FIRハーフバンドフィルタの設計
猪爪堅太郎; 張煕; 吉川敏則
Public symposium, Japanese, 第13回ディジタル信号処理シンポジウム, 第13回ディジタル信号処理シンポジウム
Nov. 1998

実全域通過関数を用いた直線位相QMFバンクの設計
六車朝信; 張煕; 吉川敏則
Public symposium, Japanese, 第13回ディジタル信号処理シンポジウム, 第13回ディジタル信号処理シンポジウム
Nov. 1998

空間周波数領域における回転不変モーメント量を用いるリモートセンシング画像の教師つきテクスチャ分類
奥村浩; 成田常晃; 梶原康司; 張煕; 吉川敏則
Oral presentation, Japanese, 日本リモートセンシング学会第25回学術講演会
Nov. 1998

複素全域通過関数による直線位相QMFバンクの設計
加藤明,張煕; 吉川敏則
Oral presentation, Japanese, 平成10年度電子情報通信学会信越支部大会
Oct. 1998

GAとSAを用いた縦続形FIRフィルタの低感度構成法
泉山英臣; 吉川敏則; 張煕
Oral presentation, Japanese, 平成10年度電子情報通信学会信越支部大会
Oct. 1998

GAを用いた有限語長FIRフィルタの設計
上林俊也; 吉川敏則; 張煕
Oral presentation, Japanese, 平成10年度電子情報通信学会信越支部大会
Oct. 1998

FFTによるFIRフィルタの複素チェビシェフ近似
鈴木一喜; 張煕; 吉川敏則
Oral presentation, Japanese, 平成10年度電子情報通信学会信越支部大会
Oct. 1998

平坦度を考慮したFIRディジタルフィルタの設計
辻和孝; 吉川敏則; 張煕
Oral presentation, Japanese, 平成10年度電子情報通信学会信越支部大会
Oct. 1998

多変量解析手法を用いた経時変化領域抽出用画像再構成手法
内山克史; 奥村浩; 吉川敏則; 張煕
Oral presentation, Japanese, 平成10年度電子情報通信学会信越支部大会
Oct. 1998

任意の平坦度を有する低遅延FIRハーフバンドフィルタの設計
猪爪堅太郎; 張煕; 吉川敏則
Oral presentation, Japanese, 1998年電子情報通信学会総合大会
Mar. 1998

シミュレーティッドアニーリングを用いた縦続形FIRディジタルフィルタの低感度構成
泉山英臣; 吉川敏則; 張煕
Oral presentation, Japanese, 1998年電子情報通信学会総合大会
Mar. 1998

全域通過回路を用いた直線位相QMFバンクの設計
六車朝信; 張煕; 吉川敏則
Oral presentation, Japanese, 1998年電子情報通信学会総合大会
Mar. 1998

通過域平坦阻止域等リプル特性を持つIIRディジタルフィルタの設計
張煕; 吉川敏則
Oral presentation, Japanese, 1998年電子情報通信学会総合大会
Mar. 1998

空間パワースペクトルと回転不変モーメントを用いたテクスチャ分類
成田常晃; 奥村浩; 吉川敏則; 張煕
Oral presentation, Japanese, 1998年電子情報通信学会総合大会
Mar. 1998

ケプストラムモーメントを用いた縦続形FIRフィルタの係数量子化効果の評価について
池田高志; 吉川敏則; 張煕
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

低遅延特性を有する最大平坦ハーフバンドフィルタの設計
猪爪堅太郎; 張煕; 吉川敏則
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

パワースペクトルモーメントの定義とフィルタに対する特性について
金永洛; 吉川敏則; 張煕
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

全域通過回路による2チャネル完全再構成フィルタバンクの設計
六車朝信; 張煕; 吉川敏則
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

リモートセンシング画像分類のためのテクスチャ定量化に関する研究
成田常晃; 奥村浩; 吉川敏則; 張煕
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

リモートセンシング画像歪み補正用対応点対の自動選定 --- 点対の選定と評価
渡邉勝之; 奥村浩; 吉川敏則; 張煕
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

ニューラルネットワークを用いた局所的降霜予測 --- 降霜現象と最低気温に関する一考察
大津孝男; 奥村浩; 吉川敏則; 張煕
Oral presentation, Japanese, 平成9年度電子情報通信学会信越支部大会
Oct. 1997

全域通過回路を用いた安定なIIR完全再構成フィルタバンクの設計
張煕; 吉川敏則
Oral presentation, Japanese, 1997年電子情報通信学会ソサイエティ大会
Sep. 1997

低遅延特性を有する FIR ナイキストフィルタの設計
張煕,石川誠; 吉川敏則
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Jul. 1997

一次元全域通過回路を用いた二次元ノッチフィルタの設計
張煕,有森亨; 吉川敏則
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Jul. 1997

低遅延特性を有する FIR ナイキストフィルタの設計
張煕,石川誠; 吉川敏則
Oral presentation, Japanese, 1997年電子情報通信学会総合大会
Mar. 1997

Recursive Orthonormal Wavelet Bases with Vanishing Moments
X.Zhang; T.Yoshikawa; H.Iwakura
Oral presentation, English, 第11回ディジタル信号処理シンポジウム, 11th Digital Signal Processing Symposium, Domestic conference
Nov. 1996

フィルタ係数量子化に対するスペクトルモーメント特性について
金永洛; 吉川敏則; 張煕
Oral presentation, Japanese, 平成8年度電子情報通信学会信越支部大会
Sep. 1996

巡回型直交ウェーブレット基底
張煕; 入江健一; 岩倉博
Oral presentation, Japanese, 1996年電子情報通信学会総合大会
Mar. 1996

通過域平坦且つ阻止域等リプル特性を指定するIIRフィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 1996年電子情報通信学会総合大会
Mar. 1996

Design of IIR Nyquist Filters with Zero Intersymbol Interference
X.Zhang; H.Iwakura
Public symposium, English, 第10回ディジタル信号処理シンポジウム, 10th Digital Signal Processing Symposium
Nov. 1995

RemezアルゴリズムによるFIR Nyquistフィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 1995年電子情報通信学会ソサイエティ大会
Sep. 1995

有理函数的切比雪夫近似及其応用
張煕
Oral presentation, Japanese, 中国科協第二届青年学術年会論文集基礎科学分冊, 北京
Jul. 1995

Design of Complex Recursive Digital Filters with Linear Phase Based on Eigenvalue Problem
X.Zhang; H.Iwakura
Oral presentation, English, 第8回回路とシステム軽井沢ワークショップ, 8th Karuizawa Workshop on Circuits and Systems, 軽井沢, Domestic conference
Apr. 1995

固有値問題に基づいたIIR直線位相フィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 1995年電子情報通信学会総合大会
Mar. 1995

ニューラルネットによる2のべき乗係数を用いたFIRフィルタの設計
張煕; 滝川愛; 岩倉博
Oral presentation, Japanese, 1994年電子情報通信学会春季大会
Mar. 1994

Design of IIR Digital Filters Based on Eigenvalue Problem
X.Zhang; M.Kamiizumi; H.Iwakura
Public symposium, English, 第8回ディジタル信号処理シンポジウム, 8th Digital Signal Processing Symposium
Oct. 1993

固有値問題に基づいたIIRディジタルフィルタの設計
上泉正恵; 張煕,岩倉博
Oral presentation, Japanese, 1993年電子情報通信学会秋季大会
Sep. 1993

全域通過回路を用いたIIR直線位相フィルタの設計
張煕; 島田肇; 岩倉博
Oral presentation, Japanese, 1993年電子情報通信学会春季大会
Mar. 1993

ニューラルネットによる離散係数FIRフィルタの設計
陶山健仁; 張煕,岩倉博
Oral presentation, Japanese, 1993年電子情報通信学会春季大会
Mar. 1993

複素全域通過回路によるIIR QMFバンクの設計
張煕,岩倉博
Oral presentation, Japanese, 1992年電子情報通信学会秋季大会
Oct. 1992

全域通過回路を用いたMチャネルDFT QMFバンクの設計
張煕,岩倉博
Oral presentation, Japanese, 第5回回路とシステム軽井沢ワークショップ, 第5回回路とシステム軽井沢ワークショップ, 軽井沢, Domestic conference
Apr. 1992

全域通過回路を用いた指定誤差特性を有するIIRディジタルフィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 1992年電子情報通信学会春季大会
Mar. 1992

複素全域通過回路による指定誤差特性を有するIIRディジタルフィルタの設計
張煕,岩倉博
Public symposium, Japanese, 第6回ディジタル信号処理シンポジウム, 第6回ディジタル信号処理シンポジウム
Nov. 1991

全域通過回路によるIIR QMFの設計
張煕,岩倉博
Oral presentation, Japanese, 1991年電子情報通信学会秋季大会
Oct. 1991

偶数次ウェイブディジタルラティスフィルタの構成
張煕,岩倉博
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Jul. 1991

全域通過回路によるコンプリメンタリ型IIRディジタルフィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Jul. 1991

全域通過回路によるコンプリメンタリ型IIR直線位相フィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 電子情報通信学会技術研究報告
May 1991

格子型回路を基本とした能動Rフィルタの構成
小林信之; 張煕,岩倉博
Oral presentation, Japanese, 電子情報通信学会技術研究報告
May 1991

ニューラルネットに基づく最小二乗近似FIR直線位相フィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Aug. 1990

ニューラルネットによるFIRディジタルフィルタの設計
張煕,岩倉博
Oral presentation, Japanese, 電子情報通信学会技術研究報告
Nov. 1989

Electric & Electronic Circuits
The University of Electro-Communications

電気・電子回路第一(J科)
電気通信大学

信号処理工学(M科)
電気通信大学

信号処理論(II類)
電気通信大学

信号処理論(S学科)
電気通信大学

信号処理論(S科)
電気通信大学

基礎演習Ａ
The University of Electro-Communications

基礎演習Ａ
The University of Electro-Communications

基礎演習Ａ
電気通信大学

情報・通信演習２
The University of Electro-Communications

情報・通信演習２
The University of Electro-Communications

情報・通信演習２
電気通信大学

Fundamental Electric Circuits
The University of Electro-Communications

基礎電気回路
電気通信大学

Signal Processing
The University of Electro-Communications

信号処理論
電気通信大学

Fundamentals of Digital Signal Processing
The University of Electro-Communications

ディジタル信号処理基礎
電気通信大学

Electrical Circuits
The University of Electro-Communications

電気回路および演習
電気通信大学

Digital Signal Processing
首都大学東京

ディジタル信号処理
首都大学東京

The Institute of Electronics, Information and Communication Engineers

The Institute of Electric and Electronics Engineers

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画像可送符号化のための最適ウェーブレット基底に関する研究
張 煕
日本学術振興会, 科学研究費助成事業, 長岡技術科学大学, 奨励研究(A), 12750323
2000 - 2000

画像処理装置、画像処理方法、プログラム及び撮像装置
Patent right, 張 熙, 小林 達也, 特願2013-090492, Date applied: 23 Apr. 2013, The University of Electro-Communications, 特開2014-215694, Date announced: 17 Nov. 2014, 特許第6168549号, Date issued: 07 Jul. 2017, 画像合成方法

画像処理プログラムおよび画像処理装置
Patent right, 張 熙, 特願2011-263271, Date applied: 01 Dec. 2011, 国立大学法人電気通信大学, 特開2013-115798, Date announced: 10 Jun. 2013, 特許第5850365号, Date issued: 11 Dec. 2015, 多焦点画像合成