基于机器视觉的索缆六自由度位移测量方法研究

项目名称： 基于机器视觉的索缆六自由度位移测量方法研究

项目编号： No.51508105

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 建筑科学

项目作者： 吴丽君

作者单位： 福州大学

项目金额： 20万元

中文摘要： 位移是研究索缆动力学行为的重要参量。机器视觉可提供高效且经济的位移测量方案。索缆扭转导致的遮挡问题以及现场难以安装系统标定所需的标定物等情况，给机器视觉系统的应用提出了挑战。本项目提出借助带编码的筒状标志物，视觉系统可实现对索缆待测点的持续跟踪；研制有一定抗噪能力的编码标志物以提高图像质量；结合亚像素定位算法、标志物模型信息及智能算法，研究小目标模糊图像上特征点的高精度定位方法；探索基于运动柔性体上稀疏特征点的摄像机在线标定方法，采用分步方式来实现高精度、灵活的双摄像机系统标定，并结合群智能算法以优化标定精度；实现特征点三维空间坐标的高精度重构；基于刚体变换及欧拉角理论，建立标志物上特征点的三维位移与待测点六自由度（6DOF）位移之间的转换模型，研究存在噪声时的非线性寻优法，实现6DOF位移测量；研制出完成原理样机。有望简化位移监测实验，提高精度，为索缆力学行为及运动控制研究奠定实验基础。

中文关键词： 索缆位移测量；六自由度；双目视觉；非接触式；分步标定

英文摘要： Displacement is an important parameter to study the dynamic behavior of cable, and machine vision based approaches can provide a convenient， efficient and economical displacement measurement. Nevertheless, it is challenging to employ vision-based system for the cable displacement measurement, due to the unique torsion of cable, and the difficulty to find any two relatively static points on the cable. In this proposal, a two-dimensional coded cylinder-shaped target is proposed to enable the continuous tracking of a monitored point on the cable. An antinoise coding target is developed to improve the quality of captured images. Combined with sub-pixel positioning algorithm, model information of targets, and intelligent algorithms, the way to localize the feature points precisely from an unsharp image of small target is sought. The relationship between the calibration precision and the number of camera self-calibration parameters is studied, based on which a two-step calibration method is proposed to achieve high-precision, flexible calibration of binocular vision system. Optimization methods are discussed based on swarm intelligence algorithms. Then, the three-dimensional spatial coordinates of the feature point is reconstructed. Based on rigid transformation theory and the Euler angles theory, one could transform the three-dimensional displacements of a group of feature points into the 6DOF displacement of the monitored point on the cable, with the assistant of nonlinear optimization method. Prototype will be developed for testing purpose. After all of these efforts, it is expected to greatly facilitate the displacement measurement, and provide accurate data for the cable mechanical behavior study as well as for the motion control.

英文关键词： Cable Displacement Measurement ;Six Degree of Freedom;Binocular Vision;Non-Contact;Two-Step Calibration