Comparison of methods for detecting corner points from digital curves-a preliminary report

The authors report on the results of a comparison of seven methods for detecting corner points from given digital curves. In the experiments, they used two sets of input curves: flowchart symbol images and figures used in the past literature. Criteria for comparing the detection results are: extent of co-incidence with human results, processing time, and invariance to rotation, to size change, and to reflection. For flowchart symbol images, the method using n-codes produced the best result in the shortest processing time. However, for the figures from the literature Rosenfeld-Weszka's method (A. Rosenfeld, J.S. Weszka, 1975) worked best. No consistent conclusion has been made for invariance tests yet