The Computer Measurement Method Research on Shaft’s Size by the Platform of the Optoelectronic Imaging

The measurement of shaft’s size by computer is the significant basis of the automatic industrial measurement and detection, this paper establishes the optoelectronic imaging instrument of the shaft, and the image data of shaft neck is acquired by the industrial camera. In the part of the image pre-processing, we propose the enhancement algorithm of edge line based on the binarization of the gradient operator to enhance the image’s edge line. After the selection of the edge lines by the user in the local region, the paper proposes a measurement method based on the paralleled edge line’s fitting and computing, which can measure the diameter of the shaft neck with the accuracy of sub-pixel. This method contains some key techniques such as the modification of the local region chosen by the user, the selection of the sample points, the fitting of the edge line, the computing method of the diameter size and so on. With the comparison of the conventional line detecting algorithm such as Hough transformation, this proposed algorithm can improve the measurement accuracy of the geometry size. In the part of the experimental results’ exhibition, we use the proposed algorithm to measure another shaft neck’s parameter and verify that the algorithm has the robust characteristic, with the comparison of the optoelectronic measurement result and the artificial measurement result, the reliability of the algorithm is verified.