基于互补型格雷编码的离焦二元光栅相位展开方法  

Phase-unwrapping method for the defocused binary grating pro filometry based on complementary Gray-coding structured light

作　　者：肖焱山[1,2] 曹益平[1] 武迎春[1] 

机构地区：[1]四川大学光电科学系,四川成都610064 [2]三峡大学理学院,湖北宜昌443002

出　　处：《光电子．激光》2013年第8期1542-1548,共7页Journal of Optoelectronics·Laser

基　　金：国家重大专项(2009ZX02204-008);国家"863"计划(2007AA01Z333);四川省学术和技术带头人培养基金(07GRC-01)资助项目

摘　　要：离焦投影使编码光图像黑白灰级跳变产生模糊而造成二值化错误,导致相位级次解码出错,影响相位展开。本文提出利用互补型格雷编码光计算相位级次,完成离焦二元光栅相位展开。生成两种编码光序列,出现误码的位置相互交错,具有互补性。结合两种互补性编码光图像进行相位展开,可有效避免编码光图像二值化错误所引起的误码影响。对陡变物体测量的结果表明,相位相对误差(RE)为1.03%,误差峰谷值(PV)为0.24rad,均方差(RMS)为0.14rad。本文方法提高了离焦二元光栅测量精度,扩大了测量范围,尤其适用于陡变或不连续物体的三维面形测量。The optical defocusing projection can produce low-pass filtering and decrease the high-frequency components of the binary grating. So the binary grating is used to produce sinusoidal fringe grating by defocusing projection in phase measuring profilometry （PMP）. And the Gray-coding light sequence is projected to evaluate the orders of the wrapped phases for phase unwrapping. However, the changes be tween the white and black fringes in the Gray-coding pattern become blurry under defocused projection, which would cause some errors in the binaryzation and make some mistakes in decoding the encoded light sequence. Based on the complementary Gray-coding light,a phase-unwrapping method is used for the de- focused binary grating in this paper. Two kinds of Gray-coding modes are projected onto the measured object, and the positions of the error words are different. So the two modes are complementary, and can avoid the influence of error words on the phase unwrapping. A steep object is successfully measured by this method. Its mean relative error is no more than 1.03% ,peak-vally （PV） error is 0.24 rad and the root-mea^square （RMS） error is 0. 14 rad. The presented method improves the phase unwrapping accu- racy,and extends the measurement range of the defocused binary grating profilometry. It is promising in measuring the 3D shape of the steep or discontinuous objects.

关 键 词：相位测量轮廓术(PMD) 离焦二元光栅 相位展开 互补格雷编码 二值化 

分 类 号：TN206[电子电信—物理电子学] O438.2[机械工程—光学工程]