PCB matching based on SURF

Purpose - The purpose of this paper is to study the application of feature-based image matching algorithm for PCB matching without using special fiducial marks. Design/methodology/approach - Speed-up robust feature (SURF) is applied to extract the interest points in PCB images. An advanced threshold is set to reject the interest points with low responses to speed up feature computation. In order to improve the performance for rotation, the descriptors are based on multi-orientations. The many-to-many tentative correspondences are determined with a maximum distance. Hough transform is used to reject the mismatches and the affine parameters are computed with a square-least solution. Findings - Results show that the method proposed in this paper can match the PCB images without using special fiducial marks effectively. The image matching algorithm shows a better performance for image rotation than the standard SURF and it succeeds in matching the image including repetitive patterns which will deteriorate the distinctiveness of feature descriptors. Research limitations/implications - Additional orientations produce more descriptors so that it takes extra time for feature description and matching. Originality/value - The paper proposes a SURF-based image matching algorithm to match the PCB images without special fiducial marks. This can reduce the complexity of PCB production. The image matching algorithm is robust to image rotation and repetitive patterns and can be used in other applications of image matching.