Recognizing objects using scale space local invariants

I n this paper we discuss a new approach to invariant signatures for recognizing curves under viewing distortions arid partial occlusion. The approach is intended to overcome the ill-posed problem ofjinding derivatives, on which local invariants usually depend. The basic idea is to use invariant finite differences, with a scale parameter that determines the size of the differencing interval. The scale parameter is allowed to vaty so that we obtain a “scale space”-like invariant representation of the curve, with larger difference intervals corresponding to largel; coarserscales. In this new representation, each traditional local invariant is replaced by n scale-dependent range of invariants. Thus, instead of invariant signature curves we obtain invariant signature sutjaces in a 3-0 invariant “scale space”.