Subpixel segmentation for ceramic defects

Because of various problems in the production of ceramics, such as material and transportation, there exists many defects in ceramics products. Traditional methods use pixel-level segmentation to locate defects which only achieve pixel-level accuracy. In order to realize higher-precision defect localization, we propose a novel subpixel interpolation method based on the blurred edge model. Based on the analysis to the gray histogram of the defect image, the threshold segmentation method is first used to roughly locate the defect. The formula for calculation of subpixel position using interpolation method is then derived, which is faster than the traditional fitting method. Finally, the 2-D subpixel edge localization problem is disassembled 1-D calculation problems in the X-direction and Y-direction according to the direction of the defect edge gradient. The subpixel location calculation method is further given. Experiments on different defects show that the proposed method can precisely segment the defects.