Accurate and robust calibration is crucial to a multisensor fusion-based system. The calibration of heterogeneous sensors is particularly challenging because of the huge difference of the captured sensor data. On the other hand, many calibration approaches ignore temporal calibration that is in fact as important as spatial calibration. In this article, we focus on the temporal calibration of heterogeneous sensors, and the corresponding extrinsic rotation is also derived. Most existing methods are specialized for a certain sensor combination, such as an inertial measurement unit (IMU) camera or a camera-Lidar system. However, heterogeneous multisensor fusion is a tendency in the robotics area, so a unified calibration method is desired. To this end, we leverage the 3-D rotational motion feature for calibration, and auxiliary calibration boards are not needed since multiple odometry methods are available to capture 3-D sensor motion. Using a high-frequency IMU as the calibration reference, an IMU-centric scheme is designed to achieve a unified framework that adapts to various target sensors that can independently estimate 3-D rotational motion. By combining independent IMU-centric calibration pairs, an arbitrary pair of sensors can also be calibrated using the same reference IMU. Due to a novel 3-D motion correlation quantification and analysis mechanism, the temporal offset can be first estimated in real time. Given temporally aligned sensor motion, the extrinsic rotation can be derived in closed-form in the same 3-D motion correlation mechanism. Experimental results of certain sensor combinations show the accuracy and robustness of the proposed method through comparison with state-of-the-art calibration approaches, and the calibration result of a heterogeneous multisensor set demonstrates the scalability and versatility of our method.

中文翻译：

---

使用运动相关分析对异构传感器进行实时时间和旋转校准

准确和稳健的校准对于基于多传感器融合的系统至关重要。由于捕获的传感器数据的巨大差异，异构传感器的校准尤其具有挑战性。另一方面，许多校准方法忽略了实际上与空间校准同样重要的时间校准。在本文中，我们专注于异构传感器的时间校准，并推导出相应的外在旋转。大多数现有方法专门用于某种传感器组合，例如惯性测量单元 (IMU) 相机或相机-激光雷达系统。然而，异构多传感器融合是机器人领域的趋势，因此需要一种统一的校准方法。为此，我们利用 3-D 旋转运动特征进行校准，不需要辅助校准板，因为可以使用多种里程计方法来捕获 3-D 传感器运动。使用高频IMU作为校准参考，以IMU为中心的方案旨在实现一个统一的框架，以适应各种可以独立估计3-D旋转运动的目标传感器。通过组合独立的以 IMU 为中心的校准对，还可以使用相同的参考 IMU 校准任意一对传感器。由于新的 3-D 运动相关量化和分析机制，可以首先实时估计时间偏移。给定时间对齐的传感器运动，可以在相同的 3-D 运动相关机制中以封闭形式导出外在旋转。