基于二进制编码条纹的三维测量方法  

Three-Dimensional Measurement Method Based on Binary Coded Fringes

作　　者：刘佳[1,2] 路长秋 文杰 肖雨倩 严飞 刘银萍[3] Liu Jia;Lu Changqiu;Wen Jie;Xiao Yuqian;Yan Fei;Liu Yinping(School of Automation,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China;Jiangsu Provincial Collaborative Innovation Center of Atmospheric Environment and Equipment Technology,Nanjing 210044,Jiangsu,China;School of Atmospheric Physics,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]南京信息工程大学自动化学院,江苏南京210044 [2]江苏省大气环境与装备技术协同创新中心,江苏南京210044 [3]南京信息工程大学大气物理学院,江苏南京210044

出　　处：《光学学报》2023年第1期120-129,共10页Acta Optica Sinica

基　　金：江苏省产业前瞻与关键核心技术重点项目(BE2020006-2);国家自然科学基金(61605083)。

摘　　要：提出一种二进制编码条纹代替正弦条纹的方法,以降低三维测量系统的非线性误差。首先,通过对传统正弦条纹一个周期内呈正弦变化的光强值进行二进制编码,将所有二进制编码的每一位分别组合生成二值条纹,投影到被测物体表面。然后,将采集到的多幅二值条纹进行叠加,生成正弦条纹。最后,结合四步相移技术,并使用互补格雷码辅助相位展开进行实验验证。实验结果表明,所提方法相比于传统四步相移方法可以有效降低非线性伽马效应导致的相位误差,提高测量精度。对直径为50.8140 mm的高精度标准球进行测量,所得的局部点云与拟合标准球的平均距离为0.0697 mm。Objective In the three-dimensional measurement technology of structured light, traditional sinusoidal fringes are lost due to the nonlinear gamma effect of digital micromirror projectors and industrial cameras, which results in phase errors and thus reduces the measurement accuracy and effect. With only two gray values, the binary fringe is not affected by the nonlinear system and can greatly improve the projection speed, and hence, it is widely studied by scholars both at home and abroad. Binary fringe defocused projection technology is widely used in three-dimensional topography measurement.In this technique, the gray sinusoidal fringes of eight bits are discretized and quantized into the binary fringes of one bit,and the sinusoidal fringes are obtained at the imaging end by the micro defocus of the projector. This method can reduce the nonlinear effect of the projector and significantly improve the measurement speed, but it can hardly grasp the defocus degree and will reduce the depth range of measurement. Given the advantages of binary fringes, this paper proposes a measurement method based on binary coded fringes. This method can combine the binary fringes with the phase-shifting technique without defocused projection to improve the measurement accuracy and effect.Methods This paper proposes a measurement method based on binary coded fringes. The modulation information of the measured object surface is obtained by the projection of multiple binary fringes, and then the sinusoidal fringes are generated by the binary superposition of binary fringes. The projection of binary fringes can avoid the direct projection of sinusoidal fringes and reduce the influence of the nonlinear system. First, the gray value of the traditional sinusoidal fringe that changes sinusoidally in a period is sampled to obtain the discrete decimal gray value of the sinusoidal fringe. The gray value is encoded in binary, and all the code words of the same rank of binary encoding are combined separately to generate binary fringes. Second,

关 键 词：测量 相移技术 非线性误差 二值条纹 二进制 

分 类 号：TN247[电子电信—物理电子学]