Dequantization bias for JPEG decompression

J. R. Price, M. Rabbani

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

Standard JPEG decompression reconstructs quantized DCT coefficients to the center for the quantization bin. This fails to exploit the nonuniform distribution of the AC coefficients. Assuming a Laplacian distribution, we derive a maximum likelihood estimate of the Laplacian parameter, based on the quantized coefficients available at the decoder, and use this estimate to optimally bias the reconstruction levels during decompression. As a decoder enhancement, this technique is fully compatible with the JPEG standard and does not modify the JPEG compressed bit stream. Extensive simulations indicate that, at typical compression ratios, biased reconstruction results in modest PSNR improvements-about 0.25 dB or higher-and slight subjective improvements, for little or no computational cost. Furthermore, simulations show that the PSNR improvements are very close (within 0.07 dB) to the best theoretically possible.

Original languageEnglish
Title of host publicationProceedings - International Conference on Information Technology
Subtitle of host publicationCoding and Computing, ITCC 2000
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages30-35
Number of pages6
ISBN (Electronic)0769505406, 9780769505404
DOIs
StatePublished - 2000
Externally publishedYes
Event1st International Conference on Information Technology: Coding and Computing, ITCC 2000 - Las Vegas, United States
Duration: Mar 27 2000Mar 29 2000

Publication series

NameProceedings - International Conference on Information Technology: Coding and Computing, ITCC 2000

Conference

Conference1st International Conference on Information Technology: Coding and Computing, ITCC 2000
Country/TerritoryUnited States
CityLas Vegas
Period03/27/0003/29/00

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