INVARIANT MATCHING AND IDENTIFICATION OF CURVES USING B-SPLINES CURVEREPRESENTATION

There have been many techniques for curve shape representation and ana lysis, ranging from Fourier descriptors, to moments, to implicit polyn omials, to differential geometry features, to time series models, to B -splines, etc. The B-splines stand as one of the most efficient curve (surface) representations and possess very attractive properties such as spatial uniqueness, boundedness and continuity, local shape control lability, and invariance to affine transformations. These properties m ade them very attractive for curve representation, and consequently, t hey have been extensively used in computer-aided design and computer g raphics. Very little work, however, has been devoted to them for recog nition purposes. One possible reason might be due to the fact that the B-spline curve is not uniquely described by a single set of parameter s (control points), which made the curve matching (recognition) proces s difficult when comparing the respective parameters of the curves to be matched. This paper is an attempt to find matching solutions despit e this limitation, and as such, it deals the problem of using B-spline s for shape recognition and identification from curves, with an emphas is on the following applications: affine invariant matching and classi fication of 2-D curves with applications in identification of aircraft types based on image silhouettes and writer-identification based on h andwritten text.