Fuzzy Rule based Median Filter for Gray-scale Images

The paper proposes a new algorithm for detection and filtering of impulse noise from gray-scale images. The detection scheme consists of two stages. In the first stage, it is tested whether the centre pixel in the window of the image is healthy or not by incorporating the condition of the rank-conditioned median filter. The centre pixel may be an impulse if it lies outside the trimming range. The first stage is empowered by the second stage, in which the centre pixel is further clarified by the soft thresholding method of impulse detection by Arakawa’s fuzzy-based median filter. The centre pixel is replaced by the median of the pixels in the window, if both stages conclude that the centre pixel is an impulse noise. It was shown experimentally that the proposed method outperforms the other methods under consideration visually and in term of PSNR values.