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Dive into the research topics where William C. Lynch is active.

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Featured researches published by William C. Lynch.


international conference on image processing | 1999

Low cost video compression using fast, modified Z-coding of wavelet pyramids

William C. Lynch; Krasimir D. Kolarov; Bill Arrighi

This paper describes a fast, low-complexity, entropy efficient video coder for wavelet pyramids. This coder approaches the entropy-limited coding rate of video wavelet pyramids, is fast in both hardware and software implementations, and has low complexity (no multiplies) for use in ASICs. It consists of a modified Z-coder used to code the zero/non-zero significance function and Huffman coding for the non-zero coefficients themselves. Adaptation is not required. There is a strong speed-memory trade-off for the Huffman tables allowing the coder to be customized to a variety of platform parameters.


data compression conference | 1997

Compression of functions defined on surfaces of 3D objects

K. Kolarav; William C. Lynch

We present a technique to compress scalar functions defined on 2-manifolds. Our approach combines discrete wavelet transforms with zerotree compression, building on ideas from three previous developments: the lifting scheme, spherical wavelets, and embedded zerotree coding methods. Applications lie in the efficient storage and rapid transmission of complex data sets. Typical data sets are Earth topography, satellite images, and surface parametrizations. Our contribution is the novel combination and application of these techniques to general 2-manifolds.


Applications of digital image processing. Conference | 1997

Wavelet compression for 3D and higher-dimensional objects

Krasimir D. Kolarov; William C. Lynch

We present a technique to compress scalar functions defined on 2-manifolds of arbitrary topology. Our approach combines discrete wavelet transforms with zerotree compression, building on ideas from three previous developments: the lifting scheme, spherical wavelets, and embedded zerotree coding methods. Applications lie in the efficient storage and rapid transmission of complex data sets. Typical data sets are earth topography, satellite images, and surface parameterizations. Our contribution in this paper is the novel combination and application of these techniques to general 2-manifolds.


Proceedings. Compression and Complexity of SEQUENCES 1997 (Cat. No.97TB100171) | 1997

Optimization of the SW algorithm for high-dimensional compression

Krasimir D. Kolarov; William C. Lynch

This paper describes an algorithm and a software package SW (Spherical Wavelets) that implements a method for compression of scalar functions defined on 3D objects. This method combines discrete second generation wavelet transforms with an extension of the embedded zerotree coding method. We present some results on optimizing the performance of the SW algorithm via the use of arithmetic coding, different scaling and norms of the wavelet coefficients. We describe an extension of the SW algorithm using different prediction schemes in the zerotree mechanism. The combined use of those techniques leads to a significant improvement of the compression performance of SW.


SPIE's International Symposium on Optical Science, Engineering, and Instrumentation | 1999

Very low cost video wavelet codec

Krasimir D. Kolarov; William C. Lynch

This paper describes a motion Wavelet transform Zero Tree (WZT) codec which achieves good compression ratios and can be implemented in a single ASIC of modest size (and very low cost). WZT includes a number of trade-offs which reduce the compression rate but which simplify the implementation and reduce the cost. The figure of merit in our codec is ASIC silicon area required, and we are willing to sacrifice some rate/distortion performance with respect to the best available algorithms to that goal. The codec employs a group of pictures (GOP) of two interlaced video frames (i.e., four video fields). Each such field is coded by the well-known transform method, whereby the image is subjected to a 2-D linear transform, the transform values are quantized, and the resulting values coded (e.g., by a zero-tree method). To that goal we are using 3D wavelet transform, dyadic quantization and various entropy codecs. In the temporal direction a temporal transform is used instead of motion estimation. Some of the technical innovations that enable the above features set are: (1) Edge filters which enable blockwise processing while preserving quadratic continuity across block boundaries, greatly reducing blocking artifacts. (2) Field image compression which reduces memory requirements for fields within a GOP.


data compression conference | 1999

A fractional chip wavelet zero tree codec (WZT) for video compression

Krasimir D. Kolarov; William C. Lynch; Bill Arrighi; Bob Hoover

[Summary form only given]. We introduce a motion wavelet transform zero tree (WZT) codec which achieves good compression ratios and can be implemented in a single ASIC of modest size. The codec employs a group of pictures (GOP) of two interlaced video frames, edge filters for the boundaries, intermediate field image compression and block compression structure. Specific features of the implementation for a small single chip are: 1) Transform filters are short and use dyadic rational coefficients with small numerators. Implementation can be accomplished with adds and shifts. We propose a Mallat pyramid resulting from five filter applications in the horizontal direction and three applications in the vertical direction. We use modified edge filters near block and image boundaries so as to utilize actual image values. 2) Motion image compression is used in place of motion compensation. We have applied transform compression in the temporal direction to a GOP of four fields. A two level temporal Mallat pyramid is used as a tensor product with the spatial pyramid. The linear edge filters are used at the fine level and the modified Haar filters at the coarse level, resulting in four temporal subbands. 3) Processing can be decoupled into the processing of blocks of 8 scan lines of 32 pixels each. This helps reduce the RAM requirements to the point that the RAM can be placed in the ASIC itself. 4) Quantization denominators are powers of two, enabling implementation by shifts. 5) Zero-tree coding yields a progressive encoding which is easily rate controlled. 6) The codec itself imposes a very low delay of less than 3.5 ms within a field and 67 ms for a GOP. The overall conclusion is that it is reasonable to expect that this method can be implemented, including memory, in a few mm/sup 2/ of silicon.


data compression conference | 1999

Fast, modified Z-coding of wavelet pyramids

William C. Lynch; Krasimir D. Kolarov; Bill Arrighi

[Summary form only given]. This paper describes a fast, low-complexity, entropy efficient coder for wavelet pyramids. This coder approaches the entropy-limited coding rate of video wavelet pyramids, is fast in both hardware and software implementations, and has low complexity for use in ASICs. It consists of a modified Z-coder used to code the zero/non-zero significance function without adaptation. The wavelet pyramid is further sharpened by scaling to match the characteristics of the human visual system (HVS). We derive the statistical characteristics of quantized wavelet pyramids from NTSC video viewed under standard conditions. These video pyramids have substantial runs of zeros and also substantial runs of non-zeros. To explore these we developed a modification of the Z-coder and explored an application of it to code zero versus non-zero. Z-codecs have the advantage of a simple (no multipliers) and fast implementation combined with coding performance approximating that of an arithmetic codec. Our experiments showed that this coder compares favorably with straight arithmetic coding. Our encoder has significant speed advantage due to low cost implementation.


Archive | 1999

Inductively coupled wireless system and method

Wayne Burdick; James H. Boyden; William C. Lynch


Archive | 1998

Border filtering of video signal blocks

William C. Lynch; Krasimir D. Kolarov; D. Robert Hoover; William J. Arrighi


Archive | 1996

Wavelet-based data compression

Krasimir D. Kolarov; William C. Lynch; Peter Schroder; Wim Sweldens

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Krasimir D. Kolarov

Interval Research Corporation

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Steven E. Saunders

Interval Research Corporation

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William J. Arrighi

Interval Research Corporation

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D. Robert Hoover

Interval Research Corporation

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Bill Arrighi

Interval Research Corporation

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Peter Schroder

Interval Research Corporation

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Wim Sweldens

University of South Carolina

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Bob Hoover

Interval Research Corporation

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James H. Boyden

Interval Research Corporation

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K. Kolarav

Interval Research Corporation

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