Abstract: PCB(Printed Circuit Board) image registration is a key step in automatic optical inspection.There are many similar graphics and area in PCB.The general method of extracting and matching of feature points is low efficiency and easy to produce false match.A fast registration algorithm based on the similarity triangle constraint was proposed,which takes specific geometric center as the feature points.The sets of centers of round and square were Delaunay triangulated.Similar triangles were found in two triangulation networks and implemented another subdivision and comparison to enhance reliability.Experiments show that the method is rigid and has higher accuracy,which can get the correct matching point of uniform distribution.

Key words: Image registration,Delaunay triangulation,Similar triangle,PCB(printed circuit board)