Patent ID: 7706612

Claim:
A method for classifying two-dimensional shapes, comprising using a computer to perform steps of: creating a training shape dataset including a similar shape group and a dissimilar shape group; computing a first average shape from the similar shape group; generating first polygonal approximations of shapes in the training shape data set and of the first average shape; generating cumulative angle turning functions for the first polygonal approximations; using the turning functions, aligning the first polygonal approximations of shapes in the training shape dataset to the first polygonal approximation of the first average shape to produce aligned shapes; computing first similarity distances between the turning functions of the aligned shapes in the training shape dataset and the first average shape; generating a distribution of the frequency of the first similarity distances for the aligned shapes; accessing a new shape; generating a second polygonal approximation of the new shape; generating a cumulative angle turning function for the second polygonal approximation; using the turning functions for the second polygonal approximation and for the first polygonal approximation of the first average shape, aligning the polygonal approximations of the new shape and the first average shape; computing a second similarity distance between the turning functions for the second polygonal approximation of the new shape and the first polygonal approximation of the first average shape; and using the distribution, classifying the new shape into either the similar shape group or the dissimilar shape group based on the second similarity distance.