Research on the Recursive and Step-by-Step Algorithm for Extraction of Point Laser Spot Center

Abstract

Whentesting the flatness of plate iron, if there is no disturbance in the spotdetection, the traditional centroid method and circle fitting method can bewell applied to extract the point laser spot center. However, the disturbanceof droplets, dusts, oil droplet and other factors are unavoidably in thepractical projects, and then the detection precision will falls sharply. In orderto solve the problem, the recursive and step-by-step method of extracting pointlaser spot center is proposed. There are two steps in this method.The thresholdcentroid method is used as the first step to extract the spots which containthe black blocks. The second step is to construct the template whose center hasa black block, then extract the black block center by running phase correlationalgorithm and the center is just the center of the point laser spot. Theresults of experiments verify that the precision of the spot center coordinateextracted by the proposed method is obviously higher than that extracted by thecentroid method and the circle fitting method with the disturbance of droplets.