EDGE-DETECTION IN MULTISPECTRAL IMAGES

This paper proposes an extension of edge detectors based on second-order differential operators to the case of multiple band (color) images. To this end, we define a local directional measure of multispectral contrast. A definition of edge point is then given, as the location of a directional maximum of the contrast function. Extremal contrast edges are defined, as loci of zero crossing points of the first directional derivative of the contrast function. The qualitative properties of the so defined edges are briefly discussed. An algorithm for edge location with subpixel resolution is proposed, with an example of application to actual RGB imagery. © 1991.