Abstract: A method to measure the vitta’s position is given in this paper.The method takes use of collimated beam projection optics and highresolution CCD to obtain images. The image acquisition, image processing are all resolved by digital signal processing(DSP) system. The processing velocity is so fast as to realize the realtime measurement. In image processing, a suitable edge detection method is used to improve the measurement accuracy. Least square method is used to fit the curves of the vitta’s position images in the data processing.