Match Planar Curve Based on Affine Invariant

Abstract

In order to recognize the curve with the same feature points but the curvature between the two adjacent feature points is different; a novel method for matching curve is proposed under the affine transformation. First feature points are matched both on model contour and object contour, then the affine region is divided for obtaining a series of sub-region's centroids by using feature points and the whole contour's centroid. Because area ratio of triangles, which constituted by centroid of the whole contour region and sub-region’s centroids, is invariant under affine transformation. We introduce area ratio of triangles to construct affine invariant, and normalized it too. And then a new recognition vector matrix is defined, and a different measure function is defined by us too. Finally the different measure value between model curve and object curve is calculated, which can be employed to judge whether the model and object are matched. Theory analysis and experiment results show the method is feasible, which can not only match the different curve but also distinguish the object with the similar shape according to the different measure value.