Three-wavelength phase-shifting interferometry selectively extracting wavelength information from wavelength-multiplexed images with arbitrary symmetric phase shifts

Abstract

We propose three-wavelength phase-shifting interferometry selectively extracting wavelength information from wavelength-multiplexed images with arbitrary phase shifts. Wavelength information is multiplexed on the space and spatial frequency domains and is separated in the polar coordinate plane by utilizing the proposed phase-shifting interferometry. 0th-order diffraction waves and conjugate images are also removed from wavelength-multiplexed images when extracting wavelengths separately. As a result, a full spatial bandwidth of a monochromatic image sensor at each wavelength is available with a small number of images. Images required for three-wavelength three-dimensional imaging with a full spatial bandwidth of a monochromatic image sensor are decreased and speeding up of measurement is expected in comparison with a conventional technique. The validity of the proposed technique is numerically confirmed.