A method determines displacements between pixels in a captured image of a reference pattern and corresponding pixels in the reference pattern including the steps of capturing the image of the reference pattern having a source pattern modulated by a plurality of carrier frequencies in a corresponding plurality of directions in the source pattern, demodulating at least three of the carrier frequencies in the captured image to form an amplitude image and a wrapped phase image for each of the carrier frequencies, and combining the wrapped phase images weighted by the amplitude images to determine the displacements between pixels in the captured image and corresponding pixels in the reference pattern.