Phase correlation is an established method for computing motion which relies on the ability to find peaks in a computed phase correlation surface. Two methods to improve the ability to detect peaks in the phase correlation surface are described herein. The first method applies a theoretically-derived and spatially-varying gain to the phase correlation surface. The gain compensates for peaks whose amplitudes have been decreased due to windowing effects; such effects are unavoidable in phase correlation. The second method uses concepts from matched filters to improve detection of peaks whose amplitudes are diminished due to a spreading of the peak energy into surrounding positions in the phase correlation surface. Peak detection filters allow such low-amplitude peaks to be properly detected. It is possible to use only the first method, or only the second method or both methods combined.