Research on combined preprocessing algorithms for detection of center circle in circular coded target image used in ART

The corded target is an indispensable part in the study of machine vision-based measurement technology, and each coded value corresponds to a different unique value, which makes it be of an important application in image recognition. Since a center circle of the circular coded target can provide precise positioning coordinate, this paper carries out the research on the combined preprocessing algorithm for detecting the center circle of circular coded target images in order to improve the recognition efficiency and accuracy of the center circle of circular coded target image of Autonomous Rail Rapid Transit(ART).Firstly, the color images captured by field experiment are gray-scale processing and smoothed by Gaussian filtering; secondly, Canny edge detection is performed on the images to accurately extract the edge features of the target images. Finally, an improved Hough transform method is used to identify the center circle contour of the extracted edges. The experimental results show that the algorithm not only improves the recognition efficiency, but also ensures the accuracy of recognition.