Chen Mingyi, Shan Qizhe. Investigation of laser speckle photography with cross-slit aperture[J]. Chinese Journal of Lasers, 1984, 11(4): 225
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Investigating the speckle pattern of a cross-slit theoretically and experimentally, we note in this paper that the object surface speckle pattern recorded on the recording plate has a 2-D gratingwise structure. After performing an optical Fourier transform on it, at the Fourier transform plane there appears a particular optical intensity distribution, a bright sharp cross-shape halo superimposed on a uniform square-shaped halo. Hence, the laser speckle photography with a cross-slit aperture will offer good quality interferogram with high contrast, low noise, and high sensitivity. Furthermore, the cross-shaped halo facilitates the measurement of fixing the original orientation of object motion as a reference coordinates. The experimental results are well consistent with the theoretical prediction.