Visual sensing and morphological image processing of weld pool in laser spot welding

A visual sensing system was established to monitor the weld pool in laser spot welding.The top-hat and bottom-hat transformation algorithms based on mathematical morphology were used to compensate for non-uniform contrast of weld pool edge.Moreover,the canny edge detector was applied to extract the weld pool profile.The edge detected results show that the morphological operation is obviously superior to the traditional contrast enhancement method.In addition,the combination of dilation and erosion was applied to eliminate the irrelevant edge details,and the smooth weld pool edge was acquired.Based on the image processing technology described above,the dynamic process of weld pool diameter during laser spot welding was obtained.