High-precision Measurement Method for Copper Plate Hole Size Based on Partial Area Effect

In the quality control of automated production, machine vision is one of the most important technologies in non-contact measurement of mold products. This paper will improve the sub-pixel edge extraction method based on partial area effect, which mainly improves two aspects: 1) enhancing the connectivity of edge segment and integrity of edge contour; 2)reducing the computational complexity of extracting target sub-pixel edges and improving detection speed. The improved method is used to measure the diameter of the circular hole of the copper plate. The experimental results show that the proposed improvement can effectively improve the accuracy of the detection of the size of the hole. The average relative accuracy is 0.16%, which is 47% higher than before improvement, and the average efficiency is 20% higher than before improvement.