应用光学, 2017, 38 (2): 256, 网络出版: 2017-04-18
数字散斑亚像素小角位移测量的曲面拟合法
Curved surface fitting method of sub-pixel small angle measurement
光学测量 数字散斑相关 亚像素 曲面拟合 散斑尺寸 小角位移 optical measurement digital speckle correlation sub-pixel curved surface fitting method speckle size small-angle displacement
摘要
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。
Abstract
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.
王志军, 于之靖, 马凯, 吴军, 诸葛晶昌. 数字散斑亚像素小角位移测量的曲面拟合法[J]. 应用光学, 2017, 38(2): 256. Wang Zhijun, Yu Zhijing, Ma Kai, Wu Jun, Zhuge Jingchang. Curved surface fitting method of sub-pixel small angle measurement[J]. Journal of Applied Optics, 2017, 38(2): 256.