A New Sinusoidal Phase Modulation Interferometry

摘要

Sinusoidal phase modulation (SPM) interferometer is a time phase modulation method, which has strong anti-jamming ability and needs higher CCD frame rate, so ordinary CCD do not meet the requirement. This article proposed a new interval sampling based on SPM. When SPM modulating signal frequency was 200 Hz, preset sampling frequency was 2,000 Hz; area array CCD with 182 Hz frame rate only collected an interference image in a modulation cycle, and then, these collected images are processed using 2,000 Hz CCD frame rate, thereby reducing the CCD frame rate. This article processed simulation and extracted phase principle values of interference images with filtering method, and by joining main interference signal in the work environment, the error analysis proved that interval sampling could improve the anti-jamming ability of SPM interferometer in the measurement of object surface topography.