QUAD-EDGE VIDEO SIGNAL DETECTOR

摘要

Apparatus and method for processing a raster scan video signal representing an image and detecting the outline of one or more objects in the image represented by the video signal. The steps of the method include encoding the raster scan video signal as a sequence of binary pixel values. For each of a plurality of the pixels the following steps are performed. It is detected when the binary pixel values representing the pixel and a horizontally adjacent pixel are distinct. It is also detected when both (a) the binary pixel values representing the pixel and a vertically adjacent pixel are distinct, and (b) the binary pixel values representing a pixel horizontally adjacent to said pixel and a pixel vertically adjacent thereto are distinct. The position of the pixel is reported when either of the detecting steps detects distinct binary pixel values. The second detecting step automatically eliminates redundant pixel reporting by eliminating the reporting of double diagonal pixels.