Hierarchical Chamfer Matching Based on Propagation of Gradient Strengths

A modification of the hierarchical chamfer matching algorithm (HCMA) with the effect that no binarisation of the edge information is performed is investigated. HCMA is a template matching algorithm used in many applications. A distance transform (DT) from binarised edges in the search image is used to guide the template to good positions. Local minima of a function using the distance values hit by the template correspond to potential matches. We propose to use distance weighted propagation of gradient magnitude information as a cost image instead of a DT from the edges. By this we keep as much information as possible until later in the matching process and, hence, do not risk to discard good matches in the edge detection and binarisation process.