Research on key technology in the real-time and high-precision spot centroid detection

This paper analyzes the influence on the centroid detection accuracy by several parameters, including the signal-to-noise ratio, frame rate and spot diameter. It provides the selection basis for the camera used in the centroid detection system. The diameter of the spot has little influence on the centroid detection accuracy within a wide range. Meanwhile, with the same signal-to-noise ratio, when the frame rate of the camera becomes higher, the centroid detection accuracy can be improved through the method of superposing more frames. The measurement software uses the specific multi-frame superposition denoising algorithm based on high speed CMOS camera which solves the conflict of improvement of accuracy and time-consuming of the algorithm. The repeatability of the centroid can reach up to 0.0023 pixel with the measuring speed of 62.5fps, the same as the frame rate of the camera.