Planar shape recognition by directional flow-change method

Abstract

A method based on directional flow-change concept is proposed in this paper for recognizing planar shapes. This method locates critical points by evaluating directional flow-changes in terms of chain code directions along the contour. An angle string can be obtained by computing the sizes of angles at the critical points and then converting them into some special angle codes. Possible shape numbers are generated by applying a set of rules to the angle string. Consequently, the task of shape recognition is transformed to the task of comparing shape numbers. Experimental results show that our method is very effective in recognizing shapes and more efficient in computation than the curve bending function (CBF) method.