Patent ID: 6996260

Claim:
A method of processing an image comprising a plurality of line objects representative of superposed arterial and venous blood vessels, so as to classify the line objects as respective arterial or venous vessels, said method comprising the steps of: processing the image so as to produce a modified image in which the width of each said line object is a single pixel; identifying pixels of the modified image which are located on a line object, and allocating to each said image point a score value dependent upon the number of adjacent pixels which are likewise located on a line; determining from the score values which of the image points is associated with a crossing point or a bifurcation of the respective line object, wherein a crossing point is represented by an image point which is the intersection of four line segments; performing a matching operation on pairs of said line segments for each said crossing point, to determine the path of blood vessels in the image, thereby classifying the line objects in the original image into two arbitrary sets, and thereafter designating one of the sets as representing venous structure, the other of the sets as representing arterial structure, depending on one or more of the following criteria: a) complexity of structure; b) average vessel density; c) average vessel width; d) vessel tortuosity; and e) vessel length.