An Enhancement in Adaptive Median Filter for Edge Preservation

Median filtering is a corner stone of medical image processing and it is extensively used in smoothing and denoising of medical images. Edges are one of the important feature in biomedical imaging for the problem such as hair crack detection, tissue damage detection. Median filter removes the noise but during the noise removal phase it also remove the edges that are important feature/information for images in classification/recognition task. In this paper an enhancement in existing median filtering has been proposed that preserve more edges without much lose in Peak signal to noise ratio(PSNR) and signal to noise ratio SNR). In this paper we also proposed a new parameter for performance evaluation Edge Retrieval Index (ERI) that evaluates the edge preservation index in images. The algorithm cleans up the imagenoise in the homogeneous areas, but preserves the edges in other region.