返回
类型 基础研究 预答辩日期 2017-10-13
开始(开题)日期 2014-12-12 论文结束日期 2017-09-05
地点 逸夫建筑馆607 论文选题来源 国家自然科学基金项目     论文字数 3.1 (万字)
题目 单相机便携式原位三维变形测量系统及其应用研究
主题词 数字图像相关, 单相机, 应变分析, 三维视觉拉伸计, 局部三维变形
摘要 数字图像相关(Digital Image Correlation, DIC)测量技术是20世纪80年代初出现的一种用于测量全场形貌、位移和变形的非干涉光学测量方法。相比于全息干涉、散斑干涉和云纹干涉等基于相干光的光学干涉技术,DIC方法除具有非接触、高分辨率等特点外,还具有对实验环境要求低、试件准备相对容易等诸多显著优势。然而,一个典型的三维数字图像相关(3D-DIC)系统通常都需要两个或两个以上的相机多角度观测目标,使用过程中3D-DIC测量系统的标定过程相对比较繁琐,在许多情况下应用受到限制。因此,需要研制一种结构紧凑,标定方便的三维变形测量装置。 运用单相机系统的数字图像相关技术实现三维形貌和变形测量是本文研究的重点内容。为实现这一目标,研制了一台便于携带,易于安装的单相机三维变形测量系统(数字图像相关应变传感(DIC-SS)),该系统不仅可以直接测量物体表面的三维形貌,而且由于测量头小巧便携,对于大型结构测量可直接安装在被测结构表面,很好地消除结构的刚体位移,获得高精度的应变测量结果。 为了保证长时间高精度的应变测量,本文提出了基于试件表面散斑图案的单相机系统自标定方法,实现了单相机3D-DIC系统的实时标定,降低环境温度等因素对测量精度的影响,大大提高了表面应变测量的稳定性。使用自标定功能的单相机3D-DIC系统已成功用做高精度的视频引伸计。 本文所研制的测量系统主要由一个相机、一个三棱镜和两个反射镜组成。反射镜和三棱镜的作用在于将一个单相机系统转换成一个双目立体视觉系统,进而利用一分为二的相机传感器从两个不同方向观测被测物体并记录图像,以此实现三维测量。论文不仅对测量头的光学设计以及运用该系统进行三维变形测量的具体步骤进行了详细论述,还通过测量中心受力的铝质圆盘的面内和离面位移验证了光学系统的有效性和测量精度 ,并通过三点弯曲试验获得了弯曲梁的表面位移和应变场。试验结果表明本文研制的测量系统可以有效地测得全场三维变形,其测量精度可以达到与多相机测量系统相同的水平。 由于所研制的测量头具有体积小、重量轻、便于安装等特点,加上自标定功能,使得本文提出的光学测量系统在三维变形测量方面有着巨大的潜在应用价值。同时,无论是在实验室还是工程实际测量,该系统都方便实用,因而,该系统将会在工业和工程实际测量中得到广泛运用。
英文题目 STUDY ON A PORTABLE IN SITU THREE-DIMENSIONAL DEFORMATION MEASUREMENT SYSTEM USING A SINGLE-CAMERA AND ITS APPLICATIONS
英文主题词 Digital image correlation, single camera, strain analysis, 3D video extensometer, local 3D deformation
英文摘要 Digital image correlation (DIC) is a non-interferometric optical metrology for full-field shape, motion and deformation measurements that was originally established in the early 1980s. Compared with other optical interferometric techniques based on the interference of coherent light, such as holographic interferometry, speckle interferometry, and moiré interferometry, the DIC technique possesses many remarkable advantages such as the requirement for a testing environment is low, preparation of the specimen is relatively easy, simple experimental setup besides non-contact and high resolution. However, a three-dimensional digital image correlation (3D-DIC) system typically consists of two or more cameras and observes a target from multiple orientations. It is restricted by its laborious calibration process in many applications. Therefore, a stereo-DIC technique using a single-camera system would be more desirable to achieve three-dimensional deformation measurements due to its compact structure and self-calibration. The main objective of this research was to investigate the aspects of the digital image correlation techniques using a single-camera for 3D shape and deformation measurement. In this thesis, a portable in situ three-dimensional deformation measurement device (digital image correlation strain sensor (DIC-SS)) was developed, which is not only used for 3D shape measurement, but also for high accuracy strain measurement as it can be attached onto the surface of the structure to remove the rigid displacement of the structure. In order to perform a long-term high accuracy strain measurement, a speckle-based self-calibration method which calibrates the single lens stereo system using the reference speckle image of the specimen instead of the calibration targets was proposed, which will make the system more convenient to be used without complicated calibration. It becomes a reality to realize in situ calibration and improve the stabilities of the system for long-term measurement. The system is used as video extensometer for non-contact, non-destructive and high-accuracy strain measurement successfully. The developed device was combined a single camera with a triangular prism mirror and two mirrors. The mirrors are utilized to convert a single camera into a stereo image system, which views a test object from two different directions and records the surface images of the test specimen on the two halves of the camera sensor, to achieve a three-dimensional measurement. The optical design and measurement procedures to obtain 3D deformation measurements of the proposed system are described in detail. The efficiency and precision of the proposed system are verified by measuring the in-plane and out-of-plane displacement of a translated plate. Moreover, a three-point bending experiment was performed on a plastic beam specimen under three points bending via an outer loading frame to determine displacements and normal strain field. The experimental results demonstrated that the proposed system can effectively and accurately measure the full-field 3D deformation and measuring accuracy have an excellent level of agreement with the multi-camera system. Because of the small size, lightweight and easy to set up the established system demonstrates great potential in determining three-dimensional deformation measurements with the aid of a single-camera and this system well-suited to both laboratory and field condition and will have significant application in the fields of engineering.
学术讨论
主办单位时间地点报告人报告主题
东南大学土木工程学院 2014.05.13 逸夫建筑馆1501 Xiao Jing Gong Application of Fracture Mechanics in Design of Composite Structure Repair
光测力学教研室 2014.06.20 逸夫建筑馆607 摩卡 工作总结
光测力学教研室 2015.04.13 逸夫建筑馆607 摩卡 工作总结
光测力学教研室 2015.11.11 逸夫建筑馆607 摩卡 工作总结
光测力学教研室 2016.07.30 逸夫建筑馆607 摩卡 工作总结
东南大学土木工程学院 2014.10.16 逸夫建筑馆1501 Patrick Chi-Kwong Luk Electric Machines and Drives the enabling technology for a new wave of electrification
东南大学土木工程学院 2015.07.01 逸夫建筑馆1501 谢礼立 土木工程灾害及其防御
东南大学土木工程学院 2015.07.02 逸夫建筑馆1501 何小元 数字图像相关测量技术及其在土木工程实验研究中的应用
     
学术会议
会议名称时间地点本人报告本人报告题目
SEM FALL Conference&International Symposium on Intensive Loading and Its Effects 2014.10.19-22 北京 development of a portable in situ three-dimensional deformation measurement system
     
代表作
论文名称
Portable device for the local three-dimensional deformation measurement using a single Camera
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
洪宝宁 正高 教授 博导 河海大学
徐志红 正高 教授 其他 南京理工大学
张建 正高 教授 博导 东南大学
衡伟 正高 教授 博导 东南大学
杨福俊 正高 教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
糜长稳 副高 副教授 东南大学