[digital image processing]
In image processing, a computing technique by which the size, colors, shading, and other characteristics of an image are altered. Typically uses an matrix of weights. The resulting calculation to each output pixel is restricted to the size of the matrix, referred to as a Kernel. Filters are used primarily in pixel-based analysis where the value of a center pixel is changed to the mean, sum, or other function of all pixel values within the filter. Image filters move systematically across a raster until each pixel has been processed.