The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
K.c. Ho - One of the best experts on this subject based on the ideXlab platform.
-
Generalized Discrete Multiwavelet Transform With Embedded Orthogonal Symmetric Prefilter Bank
IEEE Transactions on Signal Processing, 2007Co-Authors: Tai-chiu Hsung, Yu-hing Shum, K.c. HoAbstract:Prefilters are generally applied to the discrete multiwavelet transform (DMWT) for processing scalar signals. To fully utilize the benefit offered by DMWT, it is important to have the Prefilter designed appropriately so as to preserve the important properties of multiwavelets. To this end, we have recently shown that it is possible to have the Prefilter designed to be maximally decimated, yet preserve the linear phase and orthogonal properties as well as the approximation power of multiwavelets. However, such design requires the point of symmetry of each channel of the Prefilter to match with the scaling functions of the target multiwavelet system. It can be very difficult to find a compatible filter bank structure; and in some cases, such filter structure simply does not exist, e.g., for multiwavelets of multiplicity 2. In this paper, we suggest a new DMWT structure in which the Prefilter is combined with the first stage of DMWT. The advantage of the new structure is twofold. First, since the Prefiltering stage is embedded into DMWT, the computational complexity can be greatly reduced. Experimental results show that an over 20% saving in arithmetic operations can be achieved comparing with the traditional DMWT realizations. Second, the new structure provides additional design freedom that allows the resulting Prefilters to be maximally decimated, orthogonal and symmetric even for multiwavelets of low multiplicity. We evaluated the new DMWT structure in terms of computational complexity, energy compaction ratio as well as the compression performance when applying to a VQ based image coding system. Satisfactory results are obtained in all cases comparing with the traditional approaches.
-
Orthogonal symmetric Prefilter banks for discrete multiwavelet transforms
IEEE Signal Processing Letters, 2006Co-Authors: Tai-chiu Hsung, K.c. HoAbstract:Traditional design of critically sampled Prefilters for discrete multiwavelet transform ignores the preservation of the linear phase property, which is important for many applications, such as image coding and digital communications. Balanced multiwavelets solve this problem but make the filters longer. By using linear phase filter banks, we propose a simple algorithm for the design of orthogonal symmetric Prefilter banks that can be used with the discrete multiwavelet transform. The Prefilter bank resulted is orthogonal and critically sampled and can preserve the approximation power of the multiwavelet as well as the linear phase property. Experimental results show that the systems using the proposed symmetric Prefilter banks give better performance as compared with using nonlinear phase Prefilters.
Juan Yuz - One of the best experts on this subject based on the ideXlab platform.
-
Identification of continuous-time models with slowly time-varying parameters
Control Engineering Practice, 2019Co-Authors: Arturo Padilla, Hugues Garnier, Peter Young, Fengwei Chen, Juan YuzAbstract:The off-line estimation of the parameters of continuous-time, linear, time-invariant transfer function models can be achieved straightforwardly using linear Prefilters on the measured input and output of the system. The on-line estimation of continuous-time models with time-varying parameters is less straightforward because it requires the updating of the continuous-time Prefilter parameters. This paper shows how such on-line estimation is possible by using recursive instrumental variable approaches. The proposed methods are presented in detail and also evaluated on a numerical example using both single experiment and Monte Carlo simulation analysis. In addition, the proposed recursive algorithms are tested using data from two real-life systems.
Tai-chiu Hsung - One of the best experts on this subject based on the ideXlab platform.
-
Generalized Discrete Multiwavelet Transform With Embedded Orthogonal Symmetric Prefilter Bank
IEEE Transactions on Signal Processing, 2007Co-Authors: Tai-chiu Hsung, Yu-hing Shum, K.c. HoAbstract:Prefilters are generally applied to the discrete multiwavelet transform (DMWT) for processing scalar signals. To fully utilize the benefit offered by DMWT, it is important to have the Prefilter designed appropriately so as to preserve the important properties of multiwavelets. To this end, we have recently shown that it is possible to have the Prefilter designed to be maximally decimated, yet preserve the linear phase and orthogonal properties as well as the approximation power of multiwavelets. However, such design requires the point of symmetry of each channel of the Prefilter to match with the scaling functions of the target multiwavelet system. It can be very difficult to find a compatible filter bank structure; and in some cases, such filter structure simply does not exist, e.g., for multiwavelets of multiplicity 2. In this paper, we suggest a new DMWT structure in which the Prefilter is combined with the first stage of DMWT. The advantage of the new structure is twofold. First, since the Prefiltering stage is embedded into DMWT, the computational complexity can be greatly reduced. Experimental results show that an over 20% saving in arithmetic operations can be achieved comparing with the traditional DMWT realizations. Second, the new structure provides additional design freedom that allows the resulting Prefilters to be maximally decimated, orthogonal and symmetric even for multiwavelets of low multiplicity. We evaluated the new DMWT structure in terms of computational complexity, energy compaction ratio as well as the compression performance when applying to a VQ based image coding system. Satisfactory results are obtained in all cases comparing with the traditional approaches.
-
Orthogonal symmetric Prefilter banks for discrete multiwavelet transforms
IEEE Signal Processing Letters, 2006Co-Authors: Tai-chiu Hsung, K.c. HoAbstract:Traditional design of critically sampled Prefilters for discrete multiwavelet transform ignores the preservation of the linear phase property, which is important for many applications, such as image coding and digital communications. Balanced multiwavelets solve this problem but make the filters longer. By using linear phase filter banks, we propose a simple algorithm for the design of orthogonal symmetric Prefilter banks that can be used with the discrete multiwavelet transform. The Prefilter bank resulted is orthogonal and critically sampled and can preserve the approximation power of the multiwavelet as well as the linear phase property. Experimental results show that the systems using the proposed symmetric Prefilter banks give better performance as compared with using nonlinear phase Prefilters.
-
ICIP - A Generalized Orthogonal Symmetric Prefilter Banks for Discrete Multiwavelet Transforms
2006 International Conference on Image Processing, 2006Co-Authors: Tai-chiu Hsung, Daniel LunAbstract:Prefilters are generally applied to the discrete multiwavelet transform (DMWT) for processing scalar signals. To fully utilize the benefit given by the multiwavelets, we have recently shown a maximally decimated orthogonal Prefilter which preserves the linear phase property and the approximation power of the multiwavelets. However, such design requires the point of symmetry of each channel of the Prefilter to match with the scaling functions of the target multiwavelet system. A compatible filter bank structure can be very difficult to find or simply does not exist, e.g. for multiplicity 2 multiwavelets. In this paper, we suggest a new DMWT structure in which the Prefilter is combined with the first stage of DMWT. The advantage of the new structure is twofold: First, the computational complexity can be greatly reduced. Second, additional design freedom allows maximally decimated, orthogonal and symmetric Prefilters even for low multiplicity. We evaluated the computational complexity and energy compaction capability of the new DMWT structure. Satisfactory results are obtained in comparing with the traditional approaches.
-
Generalized Discrete Multiwavelet Transform with Embedded Prefilter Bank for VQ-Based Image Coding
TENCON 2006 - 2006 IEEE Region 10 Conference, 2006Co-Authors: Yu-hing Shum, Daniel P. K. Lun, Tai-chiu HsungAbstract:Prefiltering is required to initialize the scalar signal for the discrete multiwavelet transform (DMWT). Traditional Prefilters are not linear phase, often nonorthogonal or nonmaximally decimated. Recently, we suggested an orthogonal symmetric Prefilter bank (OSPFB) to tackle this problem but it was still difficult to find a compatible filter bank structure and sometimes there was none, especially for low multiplicity multiwavelets. A new generalized DMWT structure was then proposed by combining the Prefilters with the first stage of DMWT. It has the advantages of lower computational complexity and more freedom on designing the Prefilters. In this paper, the performance of the new DMWT structure is evaluated by applying to a VQ-based image coding system whose codebook is initialized with a modified approach called cumulative absolute difference (CAD). Satisfactory results are obtained in all cases comparing with the traditional approaches.
Yong Hoon Lee - One of the best experts on this subject based on the ideXlab platform.
-
Multiplierless FIR Filters Based on Cyclotomic and Interlpolated Second-Order Polynomials with Powers-of-Two Coefficients
2016Co-Authors: Yong Hoon LeeAbstract:Abstract- We propose an optimal method for designing multiplierless FIR filters with cascaded Prefilter-equalizer structures. In particular, simultaneous design of multiplierless Prefilters and equalizers based on cyclotomic polynomials (CPs) and interpolated second-order polynomials (ISOPs) with powers-of-two coefficients is introduced. After employing CPs for Prefiltering and ISOPs for equalization, a cascade of the CP Prefilter and the ISOP equalizer is simultaneously optimized by mixed integer linear programming (Mns) [l]. Design examples demonstrate that this method leads to more efficient cascaded FIR Prefilter-equalizers than existing methods. I
-
design of discrete coefficient fir and iir digital filters with Prefilter equalizer structure using linear programming
IEEE Transactions on Circuits and Systems Ii: Analog and Digital Signal Processing, 2000Co-Authors: Yong Hoon LeeAbstract:Optimal methods for designing multiplierless finite-impulse response (FIR) and infinite-impulse response (IIR) filters with cascaded Prefilter-equalizer structures are proposed. Assuming that an FIR filter consists of a cyclotomic polynomial (CP) Prefilter and an interpolated second order polynomial (ISOP) equalizer, in the proposed method, the Prefilter and equalizer are simultaneously designed using mixed integer linear programming (MILP). The resulting filter is a cascaded filter with minimal complexity. For IIR filters, all-pole IIR equalizers consisting of inverse of interpolated first order polynomials (IIFOP's) are introduced, and a CP-Prefilter cascaded with this type of equalizer is designed. Design examples demonstrate that the proposed methods produce a more efficient cascaded Prefilter-equalizer than existing methods.
-
Design of efficient FIR filters with cyclotomic polynomial Prefilters using mixed integer linear programming
IEEE Signal Processing Letters, 1996Co-Authors: Yong Hoon LeeAbstract:The cyclotomic polynomial (CP) Prefilter design problem is formulated as an optimization problem with linear objective functions by applying logarithms to the transfer function of the CP Prefilter. This problem is then solved by mixed integer linear programming (MILP). Design examples demonstrate that this method leads to more efficient cascaded finite impulse response (FIR) Prefilter-equalizers than existing methods.
-
cascade parallel form fir filters with powers of two coefficients
International Symposium on Circuits and Systems, 1994Co-Authors: Yong Hoon LeeAbstract:A Prefilter-equalizer structure for cascade form 2PFIR filtering is proposed. This structure consists of a Prefilter made up of cascaded cyclotomic polynomial (CP) filters, and an FIR equalizer having signed powers-of-two coefficients. It is shown that this Prefilter-equalizer is often easier to design, and can perform better than direct and cascade form 2PFIR filters. >
-
ISCAS - Cascade/parallel form FIR filters with powers-of-two coefficients
Proceedings of IEEE International Symposium on Circuits and Systems - ISCAS '94, 1Co-Authors: Yong Hoon LeeAbstract:A Prefilter-equalizer structure for cascade form 2PFIR filtering is proposed. This structure consists of a Prefilter made up of cascaded cyclotomic polynomial (CP) filters, and an FIR equalizer having signed powers-of-two coefficients. It is shown that this Prefilter-equalizer is often easier to design, and can perform better than direct and cascade form 2PFIR filters. >
Xianggen Xia - One of the best experts on this subject based on the ideXlab platform.
-
a new Prefilter design for discrete multiwavelet transforms
IEEE Transactions on Signal Processing, 1998Co-Authors: Xianggen XiaAbstract:In conventional wavelet transforms, Prefiltering is not necessary due to the lowpass property of a scaling function. This is no longer true for multiwavelet transforms. A few research papers on the design of Prefilters have appeared, but the existing Prefilters are usually not orthogonal, which often causes problems in coding. Moreover, the condition on the Prefilters was imposed based on the first-step discrete multiwavelet decomposition. We propose a new Prefilter design that combines the ideas of the conventional wavelet transforms and multiwavelet transforms. The Prefilters are orthogonal but nonmaximally decimated. They are derived from a very natural calculation of multiwavelet transform coefficients. In this new Prefilter design, multiple step discrete multiwavelet decomposition is taken into account. Our numerical examples (by taking care of the redundant Prefiltering) indicate that the energy compaction ratio with the Geronimo-Hardin-Massopust (1994) 2 wavelet transform and our new Prefiltering is better than the one with Daubechies D/sub 4/ wavelet transform.
-
a new Prefilter design for discrete multiwavelet transforms
Asilomar Conference on Signals Systems and Computers, 1997Co-Authors: Xianggen XiaAbstract:We propose a new Prefilter design that combines the ideas of the conventional wavelet transforms and multiwavelet transforms. The Prefilters are orthogonal but nonmaximally decimated. They are derived from a very natural calculation of multiwavelet transform coefficients. In this new Prefilter design, multiple step discrete multiwavelet decomposition is taken into account. Our numerical examples (by taking care of the redundant Prefiltering) indicate that the energy compaction ratio with the Geronimo, Hardin and Massopust (1994) 2 wavelet transform and our new Prefiltering is better than the one with Daubechies D/sub 4/ wavelet transform.
