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Filter design

About: Filter design is a research topic. Over the lifetime, 26483 publications have been published within this topic receiving 400503 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: The results show that the optimized NL-means filter outperforms the classical implementation of the NL- means filter, as well as two other classical denoising methods and total variation minimization process in terms of accuracy with low computation time.
Abstract: A critical issue in image restoration is the problem of noise removal while keeping the integrity of relevant image information. Denoising is a crucial step to increase image quality and to improve the performance of all the tasks needed for quantitative imaging analysis. The method proposed in this paper is based on a 3-D optimized blockwise version of the nonlocal (NL)-means filter (Buades, , 2005). The NL-means filter uses the redundancy of information in the image under study to remove the noise. The performance of the NL-means filter has been already demonstrated for 2-D images, but reducing the computational burden is a critical aspect to extend the method to 3-D images. To overcome this problem, we propose improvements to reduce the computational complexity. These different improvements allow to drastically divide the computational time while preserving the performances of the NL-means filter. A fully automated and optimized version of the NL-means filter is then presented. Our contributions to the NL-means filter are: 1) an automatic tuning of the smoothing parameter; 2) a selection of the most relevant voxels; 3) a blockwise implementation; and 4) a parallelized computation. Quantitative validation was carried out on synthetic datasets generated with BrainWeb (Collins, , 1998). The results show that our optimized NL-means filter outperforms the classical implementation of the NL-means filter, as well as two other classical denoising methods [anisotropic diffusion (Perona and Malik, 1990)] and total variation minimization process (Rudin, , 1992) in terms of accuracy (measured by the peak signal-to-noise ratio) with low computation time. Finally, qualitative results on real data are presented.

1,113 citations

Journal ArticleDOI
01 Jan 1990
TL;DR: Several applications of the polyphase concept are described, including subband coding of waveforms, voice privacy systems, integral and fractional sampling rate conversion, digital crossover networks, and multirate coding of narrowband filter coefficients.
Abstract: The basic concepts and building blocks in multirate digital signal processing (DSP), including the digital polyphase representation, are reviewed. Recent progress, as reported by several authors in this area, is discussed. Several applications are described, including subband coding of waveforms, voice privacy systems, integral and fractional sampling rate conversion (such as in digital audio), digital crossover networks, and multirate coding of narrowband filter coefficients. The M-band quadrature mirror filter (QMF) bank is discussed in considerable detail, including an analysis of various errors and imperfections. Recent techniques for perfect signal reconstruction in such systems are reviewed. The connection between QMF banks and other related topics, such as block digital filtering and periodically time-varying systems, is examined in a pseudo-circulant-matrix framework. Unconventional applications of the polyphase concept are discussed. >

1,067 citations

Journal ArticleDOI
TL;DR: In this paper, it is shown that modulo arithmetic may be used in the inverse filter to eliminate completely the possibility of instability, and a very simple automatic or adaptive equalisation system is presented.
Abstract: The limitations of present automatic and adaptive equalisers stem from the use of feedforward transversal filters. These drawbacks may be obviated by using a feedback transversal filter, the inverse filter, but this is only suitable for limited use since it can be an unstable circuit. It is shown that modulo arithmetic may be used in the inverse filter to eliminate completely the possibility of instability, and a very simple automatic or adaptive equalisation system is presented. Some interesting properties of the modulo inverse filter are included.

1,035 citations

Book
01 Aug 1995
TL;DR: This paper presents a meta-modelling framework for designing and characterization of digital filters for discrete-Time signal processing applications.
Abstract: 1. Sampling and Reconstruction. 2. Quantization. 3. Discrete-Time Systems. 4. FIR Filtering and Convolution. 5. z-Transforms. 6. Transfer Functions. 7. Digital Filter Realizations. 8. Signal Processing Applications. 9. DFT/FFT Algorithms. 10. FIR Digital Filter Design. 11. IIR Digital Filter Design. 12. Interpolation, Decimation, and Oversampling. 13. Appendices. References. Index.

969 citations

Book
27 Jul 2007
TL;DR: Radio Frequency Filter Networks for Wireless Communications-The System Perspective and Computer-Aided Synthesis of Characteristic Polynomials shows the impact of system design on the requirements of filter networks.
Abstract: Foreword Preface Acknowledgments 1 Radio Frequency (RF) Filter Networks for Wireless Communications-The System Perspective PART I: INTRODUCTION TO A COMMUNICATION SYSTEM, RADIO SPECTRUM, AND INFORMATION PART II: NOISE IN A COMMUNICATION CHANNEL PART III: IMPACT OF SYSTEM DESIGN ON THE REQUIRMENTS OF FILTER NETWORKS 2 Fundamentals of Circuit Theory Approximation 3 Characterization of Lossless Lowpass Prototype filter functions 4 Computer-Aided Synthesis of Characteristic Polynomials 5 Analysis of Multiport Microwave Networks 6 Synthesis of a General Class of the Chebyshev Filter Function 7 Synthesis of Network - Circuit Approach 8 Coupling Matrix Synthesis of Filter Networks 9 Reconfiguration of the Folded Coupling Matrix 10 Synthesis and Application of Extracted Pole and Trisection Elements 11 Microwave Resonators 12 Waveguide and Coaxial Lowpass Filters 13 Waveguide Realization of Single- and Dual-Mode Resonator Filters 14 Design and Physical Realization of Coupled Resonator Filters 15 Advanced EM-Based Design Techniques for Microwave Filters 16 Dielectric Resonator Filters 17 AllPass Phase and Group Delay Equalizer Networks 18 Multiplexer Theory and Design 19 Computer-Aided Diagnosis and Tuning of Microwave Filters 20 High-Power Considerations in Microwave Filter Networks Appendix A Appendix B Appendix C Appendix D Index

959 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
202351
2022176
2021353
2020452
2019511