A new algorithm for removing salt and pepper noise from color medical images

A new method for eliminating salt and pepper noise from color medical images is formulated in this work. The presence of noise in the medical images degrades image quality, affecting disease analysis, detection, and diagnosis by the doctors. Therefore, removal of noise from the medical image is crucial. For color image, vector median filter is preferred for decreasing presence of salt and pepper noise as it preserves the correlation between the channels. However, applying filter on the image without detecting the noise not only reduces noise, but also produces blurring effect in the homogeneous regions and removes the important features such as textures, edges, thin lines, curves, corners etc. presence in the images. This paper proposes a switching vector median filter that detects the salt and pepper noise in the images prior to the filtering operation to avoid such undesirable effects. The vector median filter is applied in the filtering kernel if the central vector pixel does not lie in the set of healthy vector pixels and the minimum average sums of the distances of the vector pixels that forms the edges in the four directions is more than a predetermined threshold. In comparison to existing common filters, the simulation results demonstrate the proposed filter's superior performance for color medical image in decreasing salt and pepper noise and maintaining details.