Baier Valentin, Schardt Michael, Fink Maximilian, Jakobi Martin, Koch Alexander W
Institute for Measurement Systems and Sensor Technology, Technical University of Munich, 80333 Munich, Germany.
Optics Department, Blickfeld GmbH, 80339 Munich, Germany.
Sensors (Basel). 2021 Dec 22;22(1):39. doi: 10.3390/s22010039.
LiDAR sensors are a key technology for enabling safe autonomous cars. For highway applications, such systems must have a long range, and the covered field of view (FoV) of >45° must be scanned with resolutions higher than 0.1°. These specifications can be met by modern MEMS scanners, which are chosen for their robustness and scalability. For the automotive market, these sensors, and especially the scanners within, must be tested to the highest standards. We propose a novel measurement setup for characterizing and validating these kinds of scanners based on a position-sensitive detector (PSD) by imaging a deflected laser beam from a diffuser screen onto the PSD. A so-called ray trace shifting technique (RTST) was used to minimize manual calibration effort, to reduce external mounting errors, and to enable dynamical one-shot measurements of the scanner's steering angle over large FoVs. This paper describes the overall setup and the calibration method according to a standard camera calibration. We further show the setup's capabilities by validating it with a statically set rotating stage and a dynamically oscillating MEMS scanner. The setup was found to be capable of measuring LiDAR MEMS scanners with a maximum FoV of 47° dynamically, with an uncertainty of less than 1%.
激光雷达传感器是实现安全自动驾驶汽车的关键技术。对于高速公路应用，此类系统必须具备远距离探测能力，并且大于45°的覆盖视场（FoV）必须以高于0.1°的分辨率进行扫描。现代微机电系统（MEMS）扫描仪能够满足这些规格要求，因其具有坚固性和可扩展性而被选用。对于汽车市场，这些传感器，尤其是其中的扫描仪，必须按照最高标准进行测试。我们提出了一种新颖的测量装置，用于基于位置敏感探测器（PSD）对这类扫描仪进行表征和验证，该方法是将来自漫射屏的偏转激光束成像到PSD上。一种所谓的光线追踪移位技术（RTST）被用于最小化手动校准工作量、减少外部安装误差，并能够在大视场内对扫描仪的转向角进行动态一次性测量。本文描述了根据标准相机校准的整体装置和校准方法。我们还通过使用静态设置的旋转台和动态振荡的MEMS扫描仪对其进行验证，展示了该装置的能力。结果发现该装置能够动态测量最大视场为47°的激光雷达MEMS扫描仪，不确定度小于1%。
