Denoising Approach Based on Rough Sets Theory and Multi-Directions Difference Image
Qi Huang · Journal of Chinese Computer Systems · 2006
To overcome the drawback of the preference of image filters for the type of noise, a new denoising approach based on rough sets theory and multi-directions difference image is proposed. The notions of number of directions and number of directional extremums are defined to describe the smoothness and noisiness of the pixels according to the multi-directions difference image. An image is partitioned into the smooth-noise sub-image, the impulse-noise sub-image and the unpolluted sub-image according to the smoothness and noisiness of pixels with rough sets theory. Two adaptive filters are designed for these two kinds of noise sub-images. The experiment results, compared with the other five filters, shows that the filter designed in the paper is the best in the performance of MSE, PSNR and ISNR for the four types of noise. Especially, for the salt pepper noise, the ISNR value of the designed filter is higher than that of the median filter with 35%.