采用复合光栅相位测量轮廓术进行三维测量时,从变形复合条纹中能有效地解调出相移变形条纹,此时滤波窗口的选择至关重要。通过分析噪声特征及其对频谱成分不同取向影响的差异性,寻找空间频谱在两个正交方向上的最佳滤波窗口,建立了一种提高测量精度的混合滤波窗口。数字模拟表明,所设计的混合窗口对噪声的抑制均优于矩形、三角形、布莱克曼和汉宁等滤波窗。已知高度平面的测量结果表明,采用均衡噪声和频谱泄漏的混合窗口的重构误差最小,其误差均方根比汉宁滤波窗口减小了9.64%,测量精度得到有效改善。实物测量实验验证了所提方法的可行性和有效性。

The phase-shift deformation patterns effectively demodulate from the deformed composite pattern when composite grating phase-measuring profilometry is used to perform a three-dimensional measurement; in this case, selection of the filtering window is considerably important. Further, a mixed window is proposed to improve the measurement accuracy by analyzing the characteristics of noise and their different effects on different orientations of the spectrum components and searching the best filtering window with respect to the spatial spectrum in two mutually orthogonal directions. The digital simulations show that the designed mixed window exhibits better noise suppression when compared with those exhibited by the rectangular, triangular, Blackman, and Hanning filtering windows. The measurement results obtained with respect to the known-height plane denote that the smallest reconstruction error can be obtained using the mixed window equalizing noise and spectral leakage. The root mean square error of the mixed window is reduced by 9.64% compared to that of the Hanning filtering window, and the measurement accuracy is effectively improved. Furthermore, the feasibility and effectiveness of the proposed method are verified via the physical measurement experiments.