利用抖动算法扩展深度范围的三维形貌测量术  

Depth range enhancement of three-dimensional profiling measurementtechnology based on dithering algorithms

作　　者：杨静雯 张宗华[1,2] 付莉娜 李雁玲 高楠 高峰[2] Yang Jingwen;Zhang Zonghua;Fu Lina;Li Yanling;Gao Nan;Gao Feng(School of Mechanical Engineering,Hebei University of Technology,Tianjin 300130,China;Centre for Precision Technology,University of Huddersfield,Huddersfield HD13DH,UK)

机构地区：[1]河北工业大学机械工程学院,天津300130 [2]赫德斯菲尔德大学精密技术中心,赫德斯菲尔德HD13DH

出　　处：《红外与激光工程》2023年第8期167-176,共10页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(52075147);河北省研究生创新资助项目(CXZZXX2022053);河北省科学技术厅外专引才引智项目。

摘　　要：数字条纹投影技术由于其非接触、测量精度高等特点在生物医学监测、虚拟现实以及计算机视觉等领域中应用越来越广泛。但其仍存在一定局限性,例如测量深度范围受限和投影仪存在非线性误差。二值离焦技术很好地克服了条纹投影三维测量中的非线性问题,但二值图像的高次谐波分量会造成测量误差。文中提出一种基于抖动算法的多频相位选择方法,该方法利用离焦抖动技术减少二值图像的高次谐波,避免投影仪非线性误差的影响;同时采用不同抖动算法及扫描方向调制得到二值图像,通过对比周期为12~60 pixel范围内的条纹图像在25个离焦程度下的展开相位误差分布,筛选出相应图像频率的离焦选择范围,最终确定不同离焦程度下条纹频率的最优选择。对于深度为22.5 cm被测物体进行了实验,正确恢复了大深度物体的三维形貌。实验结果表明:文中所提出的方法能有效地扩展测量深度范围,从而实现大深度范围被测物体的三维形貌测量。Objective With the rapid development of modern information technology,optical three-dimensional(3D)profiling measurement technology has gradually matured.Among numerous optical 3D profiling measurement technologies,due to its non-contact and high-accuracy measurement,digital fringe projection(DFP)technology is increasingly applied in the fields such as biomedical monitoring,virtual reality,and computer vision,and has broad prospects for development due to its non-contact and high measurement accuracy.However,this technology still faces some technical challenges:1)Due to the limited depth of field of the system equipment(such as cameras and projectors),only the 3D shape of objects within a limited depth of field can be reconstructed;2)Nonlinearity problems caused by theγ-effect of commercial projectors may affect measurement accuracy. To overcome these problems, this paper proposes a method to extend the measurement depth range,which can achieve high-accuracy measurement of multiple objects at different depths or objects with a large depthrange.Methods The paper proposes a novel method for measuring the 3D shape of objects with a large depth range.Firstly, defocus technique is used to measure the dithering pattern in a simulated sinusoidal mode, avoiding theinfluence of projector non-linear errors on 3D measurement of fringe projection and increasing the measurementspeed. Then, by analyzing the relationship between the degree of defocusing of the fringe and the depth (Fig.1-2),this paper analyses the relationship between fringe defocus and depth and finds that the defocus degree of fringesat different frequencies is inconsistent with the depth variation nodes. Based on this, a multi-frequency phaseselection method is proposed in this paper. The optimal frequency mode determination algorithm (Fig.4) is usedto select the bayer dithering algorithm and the floyd-steinberg dithering algorithm to generate dithering patterns.After comparing the phase error distribution of the fringe images within the range of 12-60 pixe

关 键 词：三维测量 条纹投影 离焦 抖动 相移法 

分 类 号：TH741[机械工程—光学工程]