A quantitative detection method of Canny-roundness for micro defects in raw ceramic microporous machining based on infrared thermal imaging technology

The nondestructive testing and evaluation of microcracks in the drilling process of raw ceramic is of great significance to improve the production quality of LTCC substrate. In this paper, based on the classical Canny operator, the microcrack images of raw porcelain extracted by CCD camera and infrared thermal imaging method are processed by optimizing gradient amplitude, automatically extracting threshold and increasing roundness detection. The analysis results of infrared thermal imaging image are compared with the processing results of high-precision CCD camera. The results show that the sensitivity of infrared thermal imaging technology to the surface microcracks of raw ceramic is higher than that of traditional high-precision CCD camera after adopting the improved canny-roundness algorithm. It can not only detect the 20 micron micro cracks on the surface of raw ceramic, but also detect the burr defects caused by laser processing in the raw ceramic.