Fringe processing method based on divide image blocks and its application

To simplify fringe processing and to enhance the processing speed and robustness, a fringe processing method based on divided image blocks is proposed. Based on a comparison of different image binarization methods, the principles and processes of image binarization and fringe thinning of this method are described. The principle and the algorithm of threshold determination are discussed. A background tone removing method and a special method of processing intermediate image parts for the improvement of image processing quality as well as the fringe thinning algorithm are described. The fringe processing method based on divided image blocks can retain useful information, remove interference and redundant information, and is of high reliability. An application of this method in Moiré deflectometry for the measurement of object surface profile is presented. Using this method, it is possible to reconstruct the surface profile only with two orthogonal Moiré deflectograms. Good results are achieved in measurements.