Image De-noising By Decision Based Expanded Window Median Filter Using Multiple Scanning

Abstract

This paper proposes a new filter for noisy imagescorrupted with salt and pepper noise which are caused due to flaws in sensor, transmission. Proposed algorithm (Decision Based Expanded Window Median Filters (DBEWMF) with multiple scanning) works on noisy pixel and noise free pixel left unchanged. Filteruses an expanded window, where processed pixel is a central pixel follows with multiple scanning of same image. Filter Expands the window size (up to 7 x 7), if window contains noisy pixels equal to or more than three forth of total pixels in orderto find more noise free pixels if still window has more noisy pixels than it will place as it is in de-noise image in first and second scanning but in third scanning replacement of processed pixel with mean value of window else window contains less than three forth noisy pixels than processed pixel is replaced using median value of window. The Proposed scheme shows better quantitatively and qualitatively in the image than standard and other algorithm.