CCD非线性效应对双频光栅三维面形测量的影响  

Influence of CCD nonlinearity effect on the three-dimensional shape measurement of dual frequency grating

作　　者：乔闹生 孙萍[4,5] QIAO Nao-sheng;SUN Ping(International College,Hunan University of Arts and Science,Changde 415000,China;Hunan Province Cooperative Innovation Center for The Construction&Development of Dongting Lake Ecological Economic Zone,Changde 415000,China;Mathematics and Physics Science College,Hunan University of Arts and Science,Changde 415000,China;College of Optoelectronic Engineering,Chengdu University of Information Technology,Chengdu 610225,China;State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China)

机构地区：[1]湖南文理学院国际学院,湖南常德415000 [2]湖南省洞庭湖生态经济区协同创新中心,湖南常德415000 [3]湖南文理学院数理学院,湖南常德415000 [4]成都信息工程大学光电工程学院,四川成都610225 [5]电子科技大学电子薄膜与集成器件国家重点实验室,四川成都6100054

出　　处：《中国光学》2021年第3期661-669,共9页Chinese Optics

基　　金：国家自然科学基金资助项目(No.61701050,No.61703157,No.61701050);电子薄膜与集成器件国家重点实验室开放课题资助项目(No.KFJJ201807);四川省教育厅科研项目(No.2018Z073)。

摘　　要：在测量系统中,CCD的非线性效应会影响复杂光学三维面形的测量精度,针对这一问题,提出采用双频光栅投影消除CCD的非线性效应以提高测量精度。首先,分析了CCD非线性效应对三维面形测量的影响,给出了该情况下出现频谱混叠的解析推导和物理解释。然后,讨论了CCD非线性效应下的双频光栅测量原理,分析了此时变形条纹的光强分布及其经傅立叶变换后得到混叠频谱的原理。最后,给出了由等效波长来衡量测量精度的方法,推出了使用双频光栅投影测量三维面形高度信息的基本公式,并进行了理论分析。对最大绝对值与平均绝对值分别为24.3181 mm和1.0839 mm的物体进行仿真分析,测量值与实际值之间的最大绝对高度误差与平均绝对高度误差分别为0.8950 mm和0.0622 mm,提高双频光栅基频后,其对应值分别减小为0.3710 mm和0.0232 mm;在实验结果显示,当双频光栅的基频都增加2.5倍后,频谱中的基频与高级频谱间分离较好,测量精度提高。因此,采用双频光栅投影消除CCD非线性效应具有较强的实用性和很好的发展前景。The CCD nonlinearity effect in the measurement system will affect the measurement accuracy of complex optical three-dimensional surface.Therefore,a method to eliminate the CCD nonlinearity effect by using dual frequency grating projection is proposed,which can improve the measurement accuracy.Firstly,the influence of CCD nonlinearity effect on three-dimensional shape measurement is analyzed.The analytical derivation and physical explanation of spectrum aliasing are given.Then,the measurement principle of dual frequency grating under the CCD nonlinearity effect is discussed.The light intensity distribution of deformed fringe and the principle of obtaining aliasing spectrum by Fourier transform are analyzed.Finally,the method to judge the measurement accuracy by the equivalent wavelength is given.The basic formula of measuring the height information of three-dimensional surface by using dual frequency grating projection is derived,and the theoretical analysis is carried out.The object is simulated as the maximum absolute value and average absolute value are 24.3181 mm and 1.0839 mm,respectively.The maximum absolute height error and average absolute height error between the measured value and the actual value are 0.8950 mm and0.0622 mm,respectively.After increasing the fundamental frequency of the dual frequency grating,the corresponding values are reduced to 0.3710 mm and 0.0232 mm,respectively.When the fundamental frequency of the dual frequency grating is increased by 2.5 times,the separation between the fundamental frequency and the advanced spectrum becomes better,and the measurement accuracy is improved.Therefore,using dual frequency grating projection to eliminate CCD nonlinearity effect has strong practicability and is highly advisable.

关 键 词：三维面形测量 双频光栅 CCD非线性效应 频谱混叠 测量精度 

分 类 号：O438.2[机械工程—光学工程]