Study on the circle center fast accurate-locating technique based on the SIFT

In allusion to the characteristics of the SIFT algorithm in the application of circle center location, redundant procedure is analyzed and a novel predigested and improved method is proposed. By estimating which pyramid octave the circle center is in, eliminating the redundancy pyramid octaves, and reducing the keypoints generated from the background by increasing the threshold for filtering out the keypoints with low contrast, the steps of assigning assistant orientations of the keypoints and generating keypoints with assistant orientation has been leaved out. Circle center detection experiments have been carried out for both standard circles generated by the computer and the real PCB location mark images. The experiment results show that, without any penalty of the location accuracy, or robustness to blur, illumination, affine transformation, the detection efficiency has been improved dramatically with the proposed improved method.