与传统测量方法相比, 数字散斑相关法由于其目标特征单元网格划分的灵活性, 能够更好地满足不同场合小角位移的测量需求。针对该方法亚像素小角位移测量的曲面拟合参数选择问题, 研究了亚像素测量图像小角旋转前后的九点二次曲面拟合法, 并根据计算机生成模拟散斑进行模拟实验分析, 得到最佳误差效率优化条件下的曲面拟合法求解亚像素小角位移的最佳散斑尺寸3.5 pixel、计算窗口尺寸41×41 pixel和拟合窗口尺寸3×3 pixel。实验验证了上述测量参数的有效性, 为进一步的曲面拟合法数字散斑成像角位移测量提供参考。

Compared with traditional measurement methods, digital speckle correlation method(DSCM) can better meet measurement requirements of small angle displacement in different occasions due to flexibility of its target feature unit meshing. In order to solve problem of sub-pixel small-angle displacement measurement, nine-point quadratic surface fitting method of sub-pixel measurement image is studied in this paper, and optimal error is obtained by computer simulating experiment. Optimal speckle size of sub-pixel small angle displacement is calculated by surface fitting method under condition of efficiency optimization. Calculation window size is 41×41 pixel and window size is 3×3 pixel. Experimental results verify validity of above parameters, and provide reference for further measurement of angular displacement of digital speckle image by surface fitting method.