High-Speed Videogrammetry with Mutually Guided Target Tracking under Occlusion for Masonry Building Structure Displacement on a Shaking Table

High-speed videogrammetric measurements are widely used on shaking tables. However, during progressive collapse experiments, the protective string used to ensure the safety of personnel and the shaking table, mandated by safety considerations, can partially occlude the structural model. To address the problem of inaccurate tracking of the ellipse targets in image sequences due to the partial occlusion, this paper proposes a novel mutually guided tracking method for the partial occlusion situations. Firstly, the strategy of loopback detection is proposed to eliminate the cumulative errors with the initial tracking model and to replace the initial results of the tracking with those from the loopback detection. Secondly, tiny offset compensation is used to solve the problem of deviations. The experimental results demonstrate that the proposed method can achieve single-point localization at the sub-millimeter level and interlayer localization at the millimeter level within partially occluded environments. It is important that the proposed method meets the requirements of experimental accuracy on shaking tables and ensures the safety of personnel and facilities.