Browsing George R. Brown School of Engineering by Author "Lang, Markus"
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Allpass Filter Design and Applications
Lang, Markus (19950115)The Problem of allpass filter design for phase approximation and equalization in the Chebyshev sense is solved by using a generalized Remez algorithm. Convergence to the unique optimum is guaranteed and is achieved rapidly ... 
Constrained Least Square Design of FIR Filters Without Specified Transition Bands
Selesnick, Ivan W.; Lang, Markus; Burrus, C. Sidney (19950115)We consider the design of digital filters and discuss the inclusion of explicitly specified transition bands in the frequency domain design of FIR filters. We put forth the notion that explicitly specified transition bands ... 
Constrained Least Square Design of FIR Filters Without Specified Transition Bands
Selesnick, Ivan W.; Lang, Markus; Burrus, C. Sidney (19960115)We consider the design of digital filters and discuss the inclusion of explicitly specified transition bands in the frequency domain design of FIR filters. We put forth the notion that explicitly specified transition bands ... 
Enhancement of Decompressed Images at Low Bit Rates
Gopinath, Ramesh A.; Lang, Markus; Guo, Haitao; Odegard, Jan E. (19940720)Transform coding at low bit rates introduces artifacts associated with the basis functions of the transform. For example, decompressed images based on the DCT (discrete cosine transform) like JPEG<sup>16</sup>  exhibit ... 
Magnitude Squared Design of Recursive Filters with the Chebyshev Norm Using a Constrained Rational Remez Algorithm
Selesnick, Ivan W.; Lang, Markus; Burrus, C. Sidney (19940501)We describe a Remez type exchange algorithm for the design of stable recursive filters for which the Chebyschev norm of H(w)  F(w) is minimized, where H(w) and F(w) are the realized and desired magnitude squared frequency ... 
Magnitude Squared Design of Recursive Filters with the Chebyshev Norm Using a Constrained Rational Remez Algorithm
Selesnick, Ivan W.; Lang, Markus; Burrus, C. Sidney (19941001)We describe a Remez type exchange algorithm for the design of stable recursive filters for which the Chebyschev norm of H(w)  F(w) is minimized, where H(w) and F(w) are the realized and desired magnitude squared frequency ... 
A New and Efficient Program for Finding All Polynomial Roots
Lang, Markus; Frenzel, BernhardChristian (19930115)Finding polynomial roots rapidly and accurately is an important problem in many areas of signal processing. We present a new program which is a combination of Muller's and Newton's method. We use the former for computing ... 
Noise Reduction Using an Undecimated Discrete Wavelet Transform
Lang, Markus; Guo, Haitao; Odegard, Jan E.; Burrus, C. Sidney; Wells, R.O. (19950115)A new nonlinear noise reduction method is presented that uses the discrete wavelet transform. Similar to Donoho and Johnstone, we employ thresholding in the wavelet transform domain but, following a suggestion by Coifman, ... 
Nonlinear phase FIR filter design with minimum LS error and additional constraints
Lang, Markus; Bamberger, Joachim (19940701)We examine the problem of approximating a complex frequency response by a realvalued FIR filter according to the <i>L<sub>2</sub></i> norm subject to additional inequality constraints for the complex error function. ... 
Nonlinear Processing of a Shift Invariant DWT for Noise Reduction
Lang, Markus; Guo, Haitao; Odegard, Jan E.; Burrus, C. Sidney; Wells, R.O. (19950320)A novel approach for noise reduction is presented. Similar to Donoho, we employ thresholding in some wavelet transform domain but use a nondecimated and consequently redundant wavelet transform instead of the usual orthogonal ... 
Nonlinear Processing of a Shift Invariant DWT for Noise Reduction
Lang, Markus; Guo, Haitao; Odegard, Jan E.; Burrus, C. Sidney; Wells, R.O. (19950420)A novel approach for noise reduction is presented. Similar to Donoho, we employ thresholding in some wavelet transform domain but use a nondecimated and consequently redundant wavelet transform instead of the usual orthogonal ... 
Nonlinear Wavelet Processing for Enhancement of Images
Odegard, Jan E.; Lang, Markus; Guo, Haitao; Gopinath, Ramesh A.; Burrus, C. Sidney (19940520)In this note we apply some recent results on nonlinear wavelet analysis to image processing. In particular we illustrate how the (soft) thresholding algorithm due to Donoho and Johnstone can successfully be used to remove ... 
Polynomial Root Finding
Lang, Markus; Frenzel, BernhardChristian (19941001)Finding polynomial roots rapidly and accurately is an important problem in many areas of signal processing. We present a program which is superior in speed and accuracy to the best methods to our knowledge, i.e., Jenkins/Traub ... 
Simultaneous Speckle Reduction and Data Compression using Best Wavelet Packet Bases with Applications to SAR based ATD/R
Wei, Dong; Guo, Haitao; Odegard, Jan E.; Lang, Markus; Burrus, C. Sidney (19950420)We propose a novel method for simultaneous speckle reduction and data compression based on shrinking, quantizing and coding the wavelet packet coefficients of the logarithmically transformed image. A fast algorithm is used ... 
Wavelet Based SAR Speckle Reduction and Image Compression
Odegard, Jan E.; Guo, Haitao; Lang, Markus; Burrus, C. Sidney; Wells, R.O.; Novak, L.M.; Hiett, M. (19950115)This paper evaluates the performance of the recently published wavelet based algorithm for speckle reduction of SAR images. The original algorithm, based on the theory of wavelet thresholding due to Donoho and Johnstone, ... 
Wavelet Based SAR Speckle Reduction and Image Compression
Odegard, Jan E.; Guo, Haitao; Lang, Markus; Burrus, C. Sidney; Wells, R.O.; Novak, L.M.; Hiett, M. (19950401)This paper evaluates the performance of the recently published wavelet based algorithm for speckle reduction of SAR images. The original algorithm, based on the theory of wavelet thresholding due to Donoho and Johnstone, ... 
Wavelet Based Speckle Reduction with Applications to SAR based ATD/R
Guo, Haitao; Odegard, Jan E.; Lang, Markus; Gopinath, Ramesh A.; Selesnick, Ivan W.; Burrus, C. Sidney (19941120)This paper introduces a novel speckle reduction method based on thresholding the wavelet coefficients of the logarithmically transformed image. The method is computational efficient and can sinificantly reduce the speckle ... 
WaveletBased PostProcessing of Low Bit Rate Transform Coded Images
Gopinath, Ramesh A.; Lang, Markus; Guo, Haitao; Odegard, Jan E. (19940115)In this paper we propose a novel method based on wavelet thresholding for enhancement of decompressed transform coded images. Transform coding at low bit rates typically introduces artifacts associated witht he basis ... 
WaveletBased PostProcessing of Low Bit Rate Transform Coded Images
Gopinath, Ramesh A.; Lang, Markus; Guo, Haitao; Odegard, Jan E. (19941101)In this paper we propose a novel method based on wavelet thresholding for enhancement of decompressed transform coded images. Transform coding at low bit rates typically introduces artifacts associated witht he basis ...