Digital image processing method to automatically detect stricture

PURPOSE: To provide a processing method of a digital blood vessel contrast image by which a stricture can be automatically detected and which is composed of the stage called the tracking stage to discriminate a picture element or a dot positioned on the center line of at least a blood vessel. CONSTITUTION: This processing method has the stage to detect a stricture by measuring intensity of a picture element running along the center line of a blood vessel, and the stage is composed of the sub-stage to decide whether or not a picture element area is a latent stricture area when a local change is shown so that intensity of the picture element takes an intermediate value between intensity of picture elements on both side of this area and intensity of a picture element of a background of an image, the sub-stage to decide an icon around the latent stricture area and the sub-stage to extract a picture element on the edge of the blood vessel in the icon. COPYRIGHT: (C)1995,JPO