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Proceedings Paper

Delicate visual artifacts of advanced digital video processing algorithms
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Paper Abstract

With the incoming of digital TV, sophisticated video processing algorithms have been developed to improve the rendering of motion or colors. However, the perceived subjective quality of these new systems sometimes happens to be in conflict with the objective measurable improvement we expect to get. In this presentation, we show examples where algorithms should visually improve the skin tone rendering of decoded pictures under normal conditions, but surprisingly fail, when the quality of mpeg encoding drops below a just noticeable threshold. In particular, we demonstrate that simple objective criteria used for the optimization, such as SAD, PSNR or histogram sometimes fail, partly because they are defined on a global scale, ignoring local characteristics of the picture content. We then integrate a simple human visual model to measure potential artifacts with regard to spatial and temporal variations of the objects' characteristics. Tuning some of the model's parameters allows correlating the perceived objective quality with compression metrics of various encoders. We show the evolution of our reference parameters in respect to the compression ratios. Finally, using the output of the model, we can control the parameters of the skin tone algorithm to reach an improvement in overall system quality.

Paper Details

Date Published: 18 March 2005
PDF: 11 pages
Proc. SPIE 5666, Human Vision and Electronic Imaging X, (18 March 2005); doi: 10.1117/12.587604
Show Author Affiliations
Marina M. Nicolas, STMicroelectronics (France)
Fritz Lebowsky, STMicroelectronics (France)

Published in SPIE Proceedings Vol. 5666:
Human Vision and Electronic Imaging X
Bernice E. Rogowitz; Thrasyvoulos N. Pappas; Scott J. Daly, Editor(s)

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