To satisfy the intelligent identification requirements of the substation inspection robot for the field meter pointer, a pointer recognition method based on the extended scan area has been proposed in this paper. Image matching is performed by the improved SIFT algorithm and the homography matrix could be obtained. The scale arc calibrated on the template image is mapped onto the test image by the homography matrix. Expanding the scanning area, the sum of the gray values of the pixel on the path of the detection line is determined. It determines the position of the pointer and calculates the reading. Five meters have been tested in this paper, and a total of 500 pictures. The experimental results show that the proposed algorithm is simple, practical, stable and has high recognition accuracy. It can identify many different meters and has strong applicability. It has higher practicability in multi-class pointer meter identification.
