Invariant Processing and Occlusion Resistant Recognition of Planar Shapes

This short paper surveys methods for planar shape smoothing and processing and planar shape recognition invariant under viewing distortions and even partial occlusions. It is argued that all the results available in the literature on these problems implicitly follow from successfully addressing two basic problems: invariant location of points with respect to a given shape (a given set of points in the plane) and invariant displacement of points with regard to the given shape.