Sub-pixel Location of Center of Target Based on Zernike Moment

To achieve high location accuracy, a sub-pixel location method based on Zernike moment is proposed for the location of the center of target. Original images are preprocessed to weaken the effect of noise. Sub-pixel edge detection is implemented using Zernike moment. The center of target is located using an ellipse fitting algorithm. Some criterions such as grayscale, area and circular degree of the objects are used to recognize the target simultaneously. Experiments are carried out with synthetic image and real image to verify the accuracy and noise immunity of the proposed method. Experimental results show that the accuracy is better than 1/25 pixel. It can therefore be concluded that the method can be used to meet the requirement of high-accuracy measurement.