Return edge detector image of a image according to an algorithm by Rachid Deriche. Matrix a is a real matrix, and n a non-negative real kernel scaling parameter (default 1.0). Specify m = 0 for a gradient magnitude result (default), m = 1 for a vector gradient result. n and m are optional arguments.
Processing time is independent on n. see for details: Klette, Zameroni: Handbuch der Operatoren fuer die Bildverarbeitung, vieweg 2. ed. 1995 pp. 224–229. Original paper: Deriche, R.: Fast algorithms for low-level vision: IEEE Trans PAMI-12 (1990) pp 78–87.
Example:
a = double(imread('myimg.png')); b = deriche(a, 1.0, 1); imshow(b(:,:,1)); imshow(b(:,:,2));