Effros, Michelle and Chou, Philip A. (2002) Weighted universal transform coding: universal image compression with the Karhunen-Loève transform. In: International Conference on Image Processing (ICIP '95), Washington, DC, 23-26 October 1995. IEEE , Los Alamitos, CA, pp. 61-64. ISBN 0 7803 3122 2 http://resolver.caltech.edu/CaltechAUTHORS:Efficip95
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We introduce a two-stage universal transform code for image compression. The code combines Karhunen-Loève transform coding with weighted universal bit allocation (WUBA) in a two-stage algorithm analogous to the algorithm for weighted universal vector quantization (WUVQ). The encoder uses a collection of transform/bit allocation pairs rather than a single transform/bit allocation pair (as in JPEG) or a single transform with a variety of bit allocations (as in WUBA). We describe both an encoding algorithm for achieving optimal compression using a collection of transform/bit allocation pairs and a technique for designing locally optimal collections of transform/bit allocation pairs. We demonstrate the performance using the mean squared error distortion measure. On a sequence of combined text and gray scale images, the algorithm achieves up to a 2 dB improvement over a JPEG style coder using the discrete cosine transform (DCT) and an optimal collection of bit allocations, up to a 3 dB improvement over a JPEG style coder using the DCT and a single (optimal) bit allocation, up to 6 dB over an entropy constrained WUVQ with first- and second-stage vector dimensions equal to 16 and 4 respectively, and up to a 10 dB improvement over an entropy constrained vector quantizer (ECVQ) with a vector dimension of 4.
|Item Type:||Book Section|
|Additional Information:||© Copyright 2002 IEEE. Reprinted with permission.|
|Subject Keywords:||image coding, image sequences, transform coding, transforms, vector quantization, source code design, universal source coding, transforms for source coding|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Lindsay Cleary|
|Deposited On:||12 Feb 2007|
|Last Modified:||26 Dec 2012 09:31|
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