Quality Improvement of Noisy Images by Wiener Filters Designed in Color Space

Kimiyoshi MIYATA*,**, Norimichi TSUMURA*, Hideaki HANEISHI* and Yoichi MIYAKE*

* Graduate School of Science and Technology, Chiba University
1-33, Yayoi-cho, Inage-ku, Chiba 263-8522, JAPAN

** Information Technology R&D Center, Mitsubishi Electric Corporation
5-1-1, Ofuna, Kamakura, Kanagawa 247-8501, JAPAN


Journal of The Society of Photographic Science and Technology of Japan, Vol.63, No. 1, pp.18-27(2000)

Abstract
We propose a new Wiener filtering method that can improve the total quality of images corrupted by additive noise without degrading the sharpness caused by the noise reduction process. The Wiener filters are designed so as to minimize the mean square error between the original and restored images in RGB color space. The Wiener filters are calculated from the covariance matrices of the observed images on the basis of the assumptions that the original image and noise have no correlation, and the noise covariance can be estimated at system characterization stage or from a uniform density area in the image. The covariance matrices of the observed images are estimated from the neighboring pixels which are selected around the current pixel with a color classification technique. Restored images by computer simulations were evaluated both objectively and subjectively. As a result, we confirmed the proposed method is effective to improve the quality of noisy images compared with the conventional filters.

Full paper ( to appeare )
[PDF][PDF figures]( in Japanese )



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