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| Content Provider | IEEE Xplore Digital Library |
|---|---|
| Author | Crouse, M. Ramchandran, Kannan |
| Copyright Year | 1995 |
| Description | Author affiliation: Beckman Inst. for Adv. Sci. & Technol., Illinois Univ., Urbana, IL, USA (Crouse, M.; Kannan Ramchandran) |
| Abstract | Previous works, including adaptive quantizer selection and adaptive coefficient thresholding, have addressed the optimization of a baseline-decodable JPEG coder in a rate-distortion (R-D) sense. In this work, by developing an entropy-constrained quantization framework, we show that these previous works do not fully realize the attainable coding gain, and then formulate a computationally efficient way that attempts to fully realize this gain for baseline-JPEG-decodable systems. Interestingly, we find that the gains obtained using the previous algorithms are almost additive. The framework involves viewing a scalar-quantized system with fixed quantizers as a special type of vector quantizer (VQ), and then to use techniques akin to entropy-constrained vector quantization (ECVQ) to optimize the system. In the JPEG case, a computationally efficient algorithm can be derived, without training, by jointly performing coefficient thresholding, quantizer selection, and Huffman table customization, all compatible with the baseline JPEG syntax. Our algorithm achieves significant R-D improvement over standard JPEG (about 2 dB for typical images) with performance comparable to that of more complex "state-of-the-art" coders. For example, for the Lenna image coded at 1.0 bits per pixel, our JPEG-compatible coder achieves a PSNR of 39.6 dB, which even slightly exceeds the published performance of Shapiro's wavelet coder. Although PSNR does not guarantee subjective performance, our algorithm can be applied with a flexible range of visually-based distortion metrics. |
| Starting Page | 342 |
| Ending Page | 351 |
| File Size | 575282 |
| Page Count | 10 |
| File Format | |
| ISBN | 0818670126 |
| ISSN | 10680314 |
| DOI | 10.1109/DCC.1995.515524 |
| Language | English |
| Publisher | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Publisher Date | 1995-03-28 |
| Publisher Place | USA |
| Access Restriction | Subscribed |
| Rights Holder | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Subject Keyword | Rate-distortion Image storage Decoding Algorithm design and analysis Transform coding Vector quantization Constraint optimization PSNR Code standards Pixel |
| Content Type | Text |
| Resource Type | Article |
| Subject | Computer Networks and Communications |
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