A robust denoising algorithm for estimating the displacement of a moving target based on the phase difference of Fourier transform phase spectrum is presented. According to shift theorem of Fourier transform

the algorithm employs the phase spectrum difference in polar coordinates of the sequence of two frame images of a moving target to search displacement through detecting the period of the phase spectrum difference or computing the slope of its section. The vectorial filtering is used to reduce noise and keep the period characteristic

and the sectional fitting is used to compute the displacement of the slope. The experimental results show that the algorithm can give the displacement of moving target with the accuracy of 1 pixel.