The precision detection of machine parts is an important part of manufacturing, which guarantees the quality for products. Image processing technology is a new testing method of precision which opens a new way for the non-contact detection. Its application is more widely with the continuous development of image processing technology. You need a comparative basic point if it needs a comparative analysis with the ideal conditions parts when it’s necessary to detect a part. In this paper, it mainly analyzes the determination of logarithmic spiral surface couplings center points.