Paper
24 June 2005 A new post-processing method for low bit rate JPEG coded images
Deqing Sun, Wai-kuen Cham, Junhao Xie
Author Affiliations +
Proceedings Volume 5960, Visual Communications and Image Processing 2005; 59603K (2005) https://doi.org/10.1117/12.632650
Event: Visual Communications and Image Processing 2005, 2005, Beijing, China
Abstract
At low bit rates (0.2bpp or below), images coded by JPEG suffer severe visual distortions. These distortions include blurred edges due to truncation of high frequency coefficients and blocking artifacts due to the block-based nature of JPEG. In this paper, we propose techniques to reduce these two artifacts so as to obtain an image of better visual quality as well as higher PSNR. For blocking artifacts, we adjust the low frequency DCT coefficients by minimizing abrupt changes in the image under certain constraint. The abrupt changes are measured using the mean square values of the difference between adjacent pixels. For blurred edges, we first detect them using the Canny edge detector and then represent them using an edge model with their parameters estimated. The distortion around these edges can then be removed by adjusting the parameters of the edge model under the quantization constraint. The method requires about four seconds for a 512x512 image using a high-end PC. Experimental results show that the proposed approach can improve the visual quality as well as the fidelity of JPEG coded images.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Deqing Sun, Wai-kuen Cham, and Junhao Xie "A new post-processing method for low bit rate JPEG coded images", Proc. SPIE 5960, Visual Communications and Image Processing 2005, 59603K (24 June 2005); https://doi.org/10.1117/12.632650
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KEYWORDS
Quantization

Image processing

Visualization

Edge detection

Image compression

Image quality

Linear filtering

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