On the robust technique of mixed Gaussian and impulsive noise reduction in color digital images

In this paper a new technique of mixed Gaussian and impulsive noise suppression in color images is proposed. The novel approach is based on a weighted average of pixels contained in the filtering block. The main novelty of the proposed solution lies in the new definition of similarity between a pixel and samples belonging to a small window centered at the central pixel of the processing block. Instead of direct comparison of pixels, a measure based on the similarity between a given pixel and the samples from the window is utilized. This measure is defined as the sum of distances in a given color space between a pixel and a certain number of most similar pixels from this window. In this way, the new similarity measure is not influenced by the outliers injected into the image by the impulsive noise process and the averaging process ensures the effectiveness of the new filter in the reduction of Gaussian noise. The experimental results prove that the novel filtering design is capable of suppressing even strong mixed noise and is competitive with respect to state-of-the-art methods.