抄録
A new algorithm of pattern tracking to calculate velocity distribution from visualized flow images is proposed. In this algorithm the similarity of a pair of image fragments is estimated with the summation of gray level differences between corresponding pixels. The summation is executed in parts, and the candidates which are judged to be dissimilar through the F-inspection are abandoned successively. This algorithm is faster than the algorithms which we have proposed till now, and also gives us the reliability of calculated vectors.