Nonlinear processing for off-axis frequency reduction in demodulation of two dimensional fringe patterns

摘要

#$%^&*AU2014259516A120160526.pdf#####- 54 ABSTRACT NONLINEAR PROCESSING FOR OFF-AXIS FREQUENCY REDUCTION IN DEMODULATION OF TWO DIMENSIONAL FRINGE PATTERNS 5 A method of demodulating an image (210) captured from an imaging system (100) having at least one two-dimensional grating (101,110,130). The captured image comprises a phase modulated fringe pattern comprising cross-term phase components (260, 270, 280, 290) resulting from presence of the at least one two-dimensional grating. The method determines (1300) parameters of at least a first non-linear transformation (h) for attenuating the cross10 term phase components. The parameters of the first non-linear transformation are determined for the imaging system to reduce artefacts in a demodulated image introduced by the crossterm phase components. The method demodulates (430, 900, 1730) the captured image by applying (420; 500, 600, 1400, 1500) at least the first non-linear transformation with the determined parameters to the captured image to attenuate the cross-term phase components. MO-71n 1 01 oa n -- ;1,-