Contrast based gradient operator derivation of one-pixel-wide edge

Describes a new edge detection technique for obtaining spatially accurate one-pixel-wide edges from a complex TV scene. The edge detection first detects multi-pixel-wide edges using contrast-based gradient operator which is formulated to respond to contrast rather than absolute brightness and reflects the real edge character without the influence of illumination. Then, it reduces the edge width by a thinning operation according to the zero crossing technique. Experimental images using modified Sobel operator as examples are illustrated for showing the efficacy of this scheme