关键词:指针式仪表,数字图像处理,运动控制驱动,指针定位 I ABSTRACT In this dissertation, an auto-detecting method of detecting analog measuring instruments, based on digital image processing technique, high-precision grating measuring technique and step-electromotor controlling technique, is put forwarded. When the digital image processing technique is applied in the precision detecting of the analog measuring instruments, it has advantages of high precision detecting, high efficiency processing and auto-detecting. In this system, the movement of the step-electromotor is controlled by computer, and then the dial pointer is drove by the step-electromotor. At the same time, these images of the analog instrument are took by high precision CCD video, and then these images will be processed by the computer, using some image-processing algorithms such as image segmentations, threshold identification, image binarization, areas labeling, dial center-point identification, useful areas identification & abstracting, and areas thinning, etc. Followed this