Abstract
Many kinds of switching-type denoising filters have been proposed to detect and denoise noisy pixels in an image effectively. Our multi-directional switching median filter uses a 2×2 pixels noise detector and an averaging method. To discriminate noisy pixels in the image, our filter requires a threshold like other switching-type filters. The optimal value of the threshold varies depending on the strength and quantity of the edge of the image, which means the optimal threshold varies from area to area of the same image. Focusing on this point, we propose a new method. It divides the image into segments and, for each of them, sets a threshold proportional to the average edge strength of the segment. Our experiment verified that this method could improve image quality.
