DIRECTIONAL VIDEO FILTERS FOR LOCALLY ADAPTIVE SPATIAL NOISE REDUCTION

摘要

Spatial noise is reduced in an image having a plurality of pixels by detecting object boundaries and unstructured areas in the image and applying 3-tap high pass filters to each pixel in the image in at least four, but less than eight directions to determine the best direction for local low pass filtering. Low pass filtering is applied only along object boundaries and unstructured areas within the image so as to minimize the tendency to blur image edges. Using only four high pass filters to locate horizontal, vertical and diagonal image edges passing through the center of a 3x3 pixel array provides good results.