Use this dialog box to remove visual “noise” or speckles from a grayscale image.
This filter adjusts the shade of gray for each pixel to create smoother transitions between shades and eliminate speckles. Enter an odd integer from 3 to 25 to specify the area to be evaluated around each pixel. A setting of 3 evaluates 8 pixels, processes an image very quickly, and retains most sharpness. A higher setting evaluates a larger area, takes more time, and produces a more blurry image.