Knowledge of the camera motion is important in the applications of structural dynamic response measurement using a vision-based approach because in most of the field measurements, such motion can be non-trivial and the accuracy of dynamic response measurements is strongly affected by the camera motion. This paper presents a new framework for camera motion estimation and vision-based displacement measurement, which greatly lowers the barriers to the application of generally positioned cameras from strictly stationary cameras. The contributions in this paper are twofold. First, camera motion as well as reconstructed structural displacement are calculated based on reference planar structures visible in a given scene. In this case, a homography is more effective at describing view changes and planar geometric constraints can be incorporated early in the reconstruction process, thereby improving the quality and effectiveness of the estimates. The second contribution is that the homography of the planar structure is estimated by a newly proposed tracking algorithm that combines RANSAC algorithm and Efficient Second-order Minimization (ESM) technique, which refines the final estimates to sub-pixel accuracy and avoids tracking drift and non-smoothness effectively. Experimental results indicate that the quality of the camera motion estimation and displacement reconstruction can be significantly improved by the judgmatical use of the proposed algorithm for planar structure homography estimation. Furthermore, nonlinear structural system identification is carried out to additionally verify the proposed algorithm using unscented Kalman filter.

中文翻译：

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位移测量和非线性结构系统识别：使用平面结构进行相机运动校正的基于视觉的方法

相机运动的知识在使用基于视觉的方法进行结构动态响应测量的应用中很重要，因为在大多数现场测量中，这种运动可能非常重要，并且动态响应测量的准确性受到相机运动的强烈影响. 本文提出了一种用于相机运动估计和基于视觉的位移测量的新框架，大大降低了从严格静止相机应用一般定位相机的障碍。本文的贡献是双重的。首先，基于给定场景中可见的参考平面结构计算相机运动以及重建的结构位移。在这种情况下，单应性在描述视图变化方面更有效，平面几何约束可以在重建过程的早期结合，从而提高估计的质量和有效性。第二个贡献是平面结构的单应性是通过结合RANSAC算法和有效二阶最小化（ESM）技术的新提出的跟踪算法来估计的，该算法将最终估计细化到亚像素精度并避免跟踪漂移和非- 平滑有效。实验结果表明，通过对所提出的平面结构单应性估计算法的判断性使用，可以显着提高相机运动估计和位移重建的质量。此外，