The paper proposes a kind of synchronous algorithms based on machine vision.What is the most important to realize synchronization is to detect the deviation angle.The method detects the deviation angle by extracting character from X-ray images.First,the method processes the image with a morphology filter,and then segments it with genetic algorithm(GA),finally extracts character with Hough transform.The experimental results show that,the algorithms detect the deviation angle precisely,and the detection velocity reaches 25 fps.Thus by controlling the servo-motor with the algorithms and a certain control rule,synchronization can be achieved.