用理论和实验的方法研究了十字孔径的散斑特性。把十字孔径用于二次曝光的散斑照相法,以测量物体在平面内的位移(或变形)时,将能显著地提高干涉条纹的对比,降低相干噪声,而且还具有灵敏度高的特点。实验的结果与理论分析得到了很好的一致。

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.