Template matching technique is used widely in many fields, such as target tracking, target recognition, image
registration, etc. Template matching based on gray measures is unstable because of illumination change and
noise. A novel template matching algorithm based on phase correlation is proposed. Phase correlation is used
to compare the similarity of two images in same size. In order to compare the similarity of two images in
different size, a new method which is named periodic stretch is proposed. Experimental results show that the
template matching algorithm based on periodic stretch phase correlation is effective.