Edge detection using Walsh functions

An operator for finding edges in a digital image is described. The operator is based on matching a subimage of a picture to a template of an ideal edge. The ideal edge is parameterized in order to simplify its representation. To further simplify the matching operation, both functions are approximated by a truncated orthogonal expansion. Using a polar form of the Walsh series as an orthogonal basis set results in an operator which is fast and returns results comparable to those of edge detectors using series approximations. The proposed operator was found to be more effective than F. O'Gorman's (1978) operator in that it finds edges more accurately and is faster.<>