Method of detecting intensity edge paths

A method of detecting intensity edge paths in an image by machine, said image being produced by a technique which is selected from the group consisting of X-ray, CAT scan, nuclear magnetic resonance, photographic, video recording, and photodetection techniques, comprising the steps of:

• (a) determine gradient magnitude and direction of the image in an array of node points using a Gaussian weighted gradient operator,
• (b) find a root node having a high probability of being on an edge path by selecting a node having a high gradient magnitude,
• (c) calculate a path metric, .GAMMA.(m.sup.i,f.sup.i), for each adjacent node to the root node which may be on the edge by calculating:
• ##EQU27## where p.sub.1 (f.sub.ri) is the probability that the pixel value F at the location .GAMMA.i arises from an edge , p.sub.0 (f.sub.ri) is the probability that the pixel value F at the location .GAMMA.i does not arise from an edge, and Pr(s.sub.i.vertline.s.sub.i-1) is the transition probability for a new transition based on the Markov process,
• (d) store the metrics for each such adjacent node.
• (e) using the adjacent node having the highest metric, calculate the metrics for other nodes adjacent thereto, and
• (f) repeat steps (d) and (e) until the edge path having the highest metric is determined.