Extracting Thermal Crack in Piston Using Dynamic Image Difference Method

At present,thermal crack is checked manually and the thermal damage procedure is hard to get,though an automatic test technique is employed in thermal shock test.A thermal shock bench was improved by incorporating an image measure system to get thermal crack information where the pictures of piston crown were taken by a CCD camera periodically during the test.An effective image differential algorithm is studied to extract thermal crack finally which can effectively resist effection of illumination variation.Image correlation based on dynamic image difference is a practical method in extracting dynamic thermal crack at the thermal shock test bench.