Surface defects inspection method in hot slab continuous casting process

Abstract

Based on the laser triangulation and machine vision technology, a three-dimensional quantitative inspection method for continuous cast slab surface defects was established, which adopted one laser and two array charge coupled device cameras and an optimal laser stripe imaging algorithm. In addition, the laser scanning system establishing method is described in detail in this paper. A laser stripe edge shape extraction method on the slab surface is proposed that utilises an improved edge scanning extraction model in accordance with the charge coupled device camera frame frequency. The detection accuracy control algorithm is presented and finally the three-dimensional image reconstruction method for slab surface defect shape was also studied. Based on the research work, the possibility of the presented laser scanning system was verified through industrial application experiments in a steel plant.

Keywords:

• Continuous casting
• Laser scanning
• CCD camera
• 3D quantitative detection
• Image processing

The authors wish to express their appreciation to the National Natural Science Foundation and Shanghai Baosteel joint project support (grant no. 50974151). The authors also thank Chongqing University for their assistance in taking some of the experiments.