Multiconstraint Spatial and Temporal Calibration of Rotating Line Structured Light Vision Sensor

Line structured light vision sensor (LSLVS) with given movement is widely used in many fields of industry for simple structure, fast scanning speed, and low power consumption. One of the applications is rotating LSLVS as a 3-D LiDAR, which is applicable to tasks with limited power consumption, such as the planetary exploration task. Accurate calibration between the LSLVS and the rotating platform is essential to such system, which is difficult for the characteristics of the movement and the problem of time synchronization. In this work, we aim to perform the spatial and the temporal calibration for the rotating LSLVS in two stages. In the first stage, the extrinsic parameters are calculated based on the image data captured in different orientations, during which the LSLVS remains static to avoid errors caused by time offset. Also, multiple constraints are added in this stage in order to have the high accuracy and robustness of calibration. Then, in the second stage, with the extrinsic parameters being precisely calibrated, the temporal calibration is performed by minimizing the reprojection errors of visual feature points, which indicates the asynchronization between the trajectory profile of the LSLVS recorded by the rotating platform and retrieved from images. The observability of the extrinsic parameters and the time delay are analyzed in detail. Simulated and realistic experiments show the competitive accuracy and robustness of the proposed method.