Identification of partially occluded objects using object chain code

A means of identifying partially occluded objects by inspecting only their visible border is presented. If one or more segments of the objects can be viewed by a top camera, then their lengths can be measured and the relative angles computed. By comparing these values with prerecorded object chain code, namely, sequences of alternate length-angle associated with each stable state of any known object, an identification may be obtained. Correct measurements of the border segments as well as their absolute angle were achieved using an especially modified Hough transform with postprocessing algorithms.