Estimating phase for phase-stepping algorithms

摘要

#$%^&*AU2012268882A120140710.pdf#####- 46 ABSTRACT ESTIMATING PHASE FOR PHASE-STEPPING ALGORITHMS A method of determining at least one actual phase offset of a fringe pattern in a captured image (301,504). The method receives a captured image having a phase modulated fringe pattern, the captured image being one of a set of images (401) captured with varying introduced phase offset and forms (402,403,404) an intermediate demodulation image (410) from the captured image, said intermediate demodulation image defining amplitude and complex phase parameters of the phase modulated fringe pattern. The captured image is transformed by a mask (506) to produce a processed captured image (803) having reduced effects of phase distortion, said mask being estimated from a function of at least one of the amplitude and complex phase parameters (501, 502, 503) defined by the intermediate demodulation image (410). The method determines (306) a Fourier transform of the processed captured image, and determines (310) at least one phase offset of the fringe pattern in the processed captured image using the mask (302,304) to identify interaction of peaks (308,309) in the Fourier transform. 6989501 1 P057180 soeci lode1/9 100 101 Receive a captured image of a phase modulated fringe pattern __11__ Form an intermediate demodulation image from the captured image 102 / Estimate a mask image and multiply the captured image by a mask to produce a 103 processed captured image having reduced effects of phase distortion Determine a Fourier transform of the processed captured image; and Determine the phase offset of the fringe 105 pattern in the processed captured image using the mask to identify interaction of peaks in the Fourier transform Figure 1 6975679 1 P057180 Fis part 1 of 2