基于互补型格雷编码的离焦二元光栅相位展开方法
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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 between 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,aphase-unwrapping method is used for the defocused 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 0.24rad and the root-mean-square(RMS)error is 0.14rad.The presented method improves the phase unwrapping accuracy,and extends the measurement range of the defocused binary grating profilometry.It is promising in measuring the 3Dshape of the steep or discontinuous objects.
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 between 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,aphase-unwrapping method is used for the defocused 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 0.24rad and the root-mean-square(RMS)error is 0.14rad.The presented method improves the phase unwrapping accuracy,and extends the measurement range of the defocused binary grating profilometry.It is promising in measuring the 3Dshape of the steep or discontinuous objects.
引文
[1]Srinivasan V,Liu H C,Halioua M.Automated phase measuring profilometry of 3-D diffuse object[J].Appl.Opt.,1984,23(18):3105-3108.
[2]Sai S G,Pramod R.Fringe projection technique:Whither we are[J].Optics and Lasers in Engineering,2010,48(2):133-140.
[3]Zhang S.Recent progress on real-time 3D shape measurement using digital fringe projection techniques[J].Optics and Lasers in Engineering,2010,48(2):149-158.
[4]Schwider J,Burow R,Elssner K E,et al.Digital wavefront measuring inerferometry:some systematic error sources[J].Applied Optics,1983,22(21):3421-3432.
[5]Lei S,Zhang S.Flexible 3-D shape measurement using projector defocusing[J].Optics Letters,2009,34(20):3080-3082.
[6]Ayubi G A,Ayubi J A,Martino J Mo,et al.Pulse-width modulation in defocused three-dimensional fringe projection[J].Optics Letters,2010,35(21):3682-3684.
[7]Gong Y Z,Zhang S.High-resolution,high-speed three-dimensional shape measurement using projector defocusing[J].Optical Engineering,2011,50(2):023603.
[8]Zhang S.High-resolution 3D profilometry with binary phase-shifting methods[J].Applied Optics,2011,50(12):1753-1757.
[9]Ayubi G A,Martion J M D,Alonso J R,et al.Three-dimensional profiling with binary fringes using phase-shifting interferometry algorithms[J].Applied Optics,2011,50(2):147-154.
[10]Zhang S.Flexible3-D shape measurement using projector defocusing:extend measurement range[J].Optics Letters,2010,35(7):934-936.
[11]SUN Xue-zhen,SU Xian-yu,ZOU Xiao-ping.Phase unwrapping based on complementary structured light binary code[J].Acta Optica Sinica,2008,28(10):1947-1951.孙学真,苏显渝,邹小平.基于互补型光栅编码的相位展开[J].光学学报,2008,28(10):1947-1951.
[12]FU Yan-jun,WU Jiang-feng,JIANG Guang-yu.Fourier transform profilometry based on defocusing[J].Optics&Laser Technology,2012,44:727-733.
[13]SU Xian-yu,ZHOU Wen-sen,Bally G V,et al.Automated phase-measuring profilometry using defocused projection of a Ronchi grating[J].Optics Communications,1992,94:561-573.
[14]WU Ying-chun,CAO Yi-ping,XIAO Yan-shan.3D shape measurement for a discontinuous object based on a dualfrequency compsite grating[J].Jouranl of Optoelectronics·Laser,2012,23(12):2362-2367.武迎春,曹益平,肖焱山.基于双频复合光栅投影的陡变物体三维面形测量[J].光电子·激光,2012,23(12):2362-2367.
[15]ZHANG Wu-ming,ZHONG Yue-xian,YOU Zhi-fu,et al.A phase unwrapping method based on structured light binary code[J].Optical Technique,2002,28(5):404-406.张吴明,钟约先,由志福,等.基于结构光编码的相展开方法[J].光学技术,2002,28(5):404-406.
[16]Jordi Pages,Joaquim Salvi,Rafael Garcia,et al.Overview of coded light projection techniques for automatic3D profiling[A].Proc.of the2013IEEE International Conference on Robotics and Automation[C].2003,133-138.
[17]HAN Pei-yu,DA Fei-peng,GAI Shao-yan.Color structured light technology for high-speed 3D shape measurement based on gray code method[J].Jouranl of Optoelectronics·Laser,2010,21(9):1359-1364.韩佩妤,达飞鹏,盖绍彦.基于格雷编码的彩色结构光快速三维测量技术[J].光电子·激光,2010,21(9):1359-1364.
[18]ZHAO Yong,SU Xian-yu,LI Wen.Phase subdivision of absolute coding grating[J].Jouranl of Optoelectronics·Laser,2010,21(1):91-95.赵勇,苏显渝,李雯.绝对编码光栅的相位细分[J].光电子·激光,2010,21(1):91-95.
[19]LU Jun,SONG Cheng-ye.Structured light system calibration based on Gray code combined with line-shift[J].Jouranl of Optoelectronics·Laser,2012,23(6):1146-1151.陆军,宋成业.基于格雷码和线移编码的结构光系统标定[J].光电子·激光,2012,23(6):1146-1151.
[20]XIAO Yan-shan,CAO Yi-ping,WU Ying-chun,et al.Gamma nonlinearity correction based on Fourier spectrum analysis for phase measuring profilometry[J].Acta Optica Sinica,2012,32(12):1212004.肖焱山,曹益平,武迎春,等.基于傅里叶频谱分析的相位测量轮廓术系统Gamma非线性校正方法[J].光学学报,2012,32(12):1212004.
[21]Ostu N A.Threshold selection method form gray level histogram[J].IEEE Transactions on Systems,Manufacture and Cybernetics,1979,9(1):62-66.
[2]Sai S G,Pramod R.Fringe projection technique:Whither we are[J].Optics and Lasers in Engineering,2010,48(2):133-140.
[3]Zhang S.Recent progress on real-time 3D shape measurement using digital fringe projection techniques[J].Optics and Lasers in Engineering,2010,48(2):149-158.
[4]Schwider J,Burow R,Elssner K E,et al.Digital wavefront measuring inerferometry:some systematic error sources[J].Applied Optics,1983,22(21):3421-3432.
[5]Lei S,Zhang S.Flexible 3-D shape measurement using projector defocusing[J].Optics Letters,2009,34(20):3080-3082.
[6]Ayubi G A,Ayubi J A,Martino J Mo,et al.Pulse-width modulation in defocused three-dimensional fringe projection[J].Optics Letters,2010,35(21):3682-3684.
[7]Gong Y Z,Zhang S.High-resolution,high-speed three-dimensional shape measurement using projector defocusing[J].Optical Engineering,2011,50(2):023603.
[8]Zhang S.High-resolution 3D profilometry with binary phase-shifting methods[J].Applied Optics,2011,50(12):1753-1757.
[9]Ayubi G A,Martion J M D,Alonso J R,et al.Three-dimensional profiling with binary fringes using phase-shifting interferometry algorithms[J].Applied Optics,2011,50(2):147-154.
[10]Zhang S.Flexible3-D shape measurement using projector defocusing:extend measurement range[J].Optics Letters,2010,35(7):934-936.
[11]SUN Xue-zhen,SU Xian-yu,ZOU Xiao-ping.Phase unwrapping based on complementary structured light binary code[J].Acta Optica Sinica,2008,28(10):1947-1951.孙学真,苏显渝,邹小平.基于互补型光栅编码的相位展开[J].光学学报,2008,28(10):1947-1951.
[12]FU Yan-jun,WU Jiang-feng,JIANG Guang-yu.Fourier transform profilometry based on defocusing[J].Optics&Laser Technology,2012,44:727-733.
[13]SU Xian-yu,ZHOU Wen-sen,Bally G V,et al.Automated phase-measuring profilometry using defocused projection of a Ronchi grating[J].Optics Communications,1992,94:561-573.
[14]WU Ying-chun,CAO Yi-ping,XIAO Yan-shan.3D shape measurement for a discontinuous object based on a dualfrequency compsite grating[J].Jouranl of Optoelectronics·Laser,2012,23(12):2362-2367.武迎春,曹益平,肖焱山.基于双频复合光栅投影的陡变物体三维面形测量[J].光电子·激光,2012,23(12):2362-2367.
[15]ZHANG Wu-ming,ZHONG Yue-xian,YOU Zhi-fu,et al.A phase unwrapping method based on structured light binary code[J].Optical Technique,2002,28(5):404-406.张吴明,钟约先,由志福,等.基于结构光编码的相展开方法[J].光学技术,2002,28(5):404-406.
[16]Jordi Pages,Joaquim Salvi,Rafael Garcia,et al.Overview of coded light projection techniques for automatic3D profiling[A].Proc.of the2013IEEE International Conference on Robotics and Automation[C].2003,133-138.
[17]HAN Pei-yu,DA Fei-peng,GAI Shao-yan.Color structured light technology for high-speed 3D shape measurement based on gray code method[J].Jouranl of Optoelectronics·Laser,2010,21(9):1359-1364.韩佩妤,达飞鹏,盖绍彦.基于格雷编码的彩色结构光快速三维测量技术[J].光电子·激光,2010,21(9):1359-1364.
[18]ZHAO Yong,SU Xian-yu,LI Wen.Phase subdivision of absolute coding grating[J].Jouranl of Optoelectronics·Laser,2010,21(1):91-95.赵勇,苏显渝,李雯.绝对编码光栅的相位细分[J].光电子·激光,2010,21(1):91-95.
[19]LU Jun,SONG Cheng-ye.Structured light system calibration based on Gray code combined with line-shift[J].Jouranl of Optoelectronics·Laser,2012,23(6):1146-1151.陆军,宋成业.基于格雷码和线移编码的结构光系统标定[J].光电子·激光,2012,23(6):1146-1151.
[20]XIAO Yan-shan,CAO Yi-ping,WU Ying-chun,et al.Gamma nonlinearity correction based on Fourier spectrum analysis for phase measuring profilometry[J].Acta Optica Sinica,2012,32(12):1212004.肖焱山,曹益平,武迎春,等.基于傅里叶频谱分析的相位测量轮廓术系统Gamma非线性校正方法[J].光学学报,2012,32(12):1212004.
[21]Ostu N A.Threshold selection method form gray level histogram[J].IEEE Transactions on Systems,Manufacture and Cybernetics,1979,9(1):62-66.