三色激光散斑自相关法测量表面粗糙度的分析

Analysis on Large Radius of Curved Surface Roughness Trichromatic Laser Speckle Autocorrelation Measurement

为研究表面弯曲对利用多色散斑测量表面粗糙度的影响,引入表面曲率半径,通过模拟粗糙表面以及其形成的多色散斑场,讨论了不同曲率半径的粗糙曲面对模拟散斑场和散斑延长率的影响。结果表明,引入粗糙表面的曲率半径,对三色激光散斑自相关测量法是可行的。粗糙表面曲率半径越大,其模拟的散斑场和计算的散斑延长率与平直的粗糙表面越接近。曲率半径越大,散斑延长率愈大,并且表面粗糙度测量误差越小。因此,在实际测量中,应该考虑表面弯曲对测量粗糙度精度的影响。

The influence of curved surface on the method of polychromatic speckle measuring surface roughness is studied by introducing surface curvature radius. The rough surface and the polychromatic speckle patterns near rough surface are simulated, and the influence of different curvature radii of rough surface on the simulated speckle patterns and ratio of speckle elongation is discussed. The results show that the factor of curvature radius of rough surface is valid in trichromatic speckle autocorrelation measurement, and the simulated speckle patterns and speckle elongation of rough surface are more similar to those of the straight surface when the curvature radius of the rough surface is larger. The larger the curvature radius is, the larger the speckle elongation becomes, and the smaller the deviation of measured surface roughness is. Therefore, influence of curvature of rough surface on measurement precision should be considered during the measuring process.