High-accuracy three-dimensional measurement based on multi-directional cooperative target with weighted SfM algorithm

Large-scale three-dimensional (3D) precision measurement is limited by the high-accuracy single-view measurement range. Therefore, it is necessary to perform multi-station coordinate transformation through high-precision 3D cooperative target to complete the measurement for large-scale objects. However, high-precision 3D cooperative target is difficult to be manufactured. The physical features on the cooperative target are also easy to occlude each other in complex measurement environments. To solve these problems and reduce the number of coordinate transformations in the process of global coordinate unification, a Multi-directional Cooperative (MDC) target consisting of designed coded planar feature target and polyhedron skeletons is designed. The designed MDC target is arbitrarily placed in the Field of View (FOV) and images of the target are obtained from multiple views. Based on the captured target images, a new Weighted SfM algorithm is proposed to realize the high-accuracy 3D measurement for the MDC target. The experimental results show that the proposed algorithm has good robustness and high accuracy for the designed MDC target.