Despite an emerging interest in MIMO radar, the utilization of its complementary strengths in combination with optical sensors has so far been limited to far-field applications, due to the challenges that arise from mutual sensor calibration in the near field. In fact, most related approaches in the autonomous industry propose target-based calibration methods using corner reflectors that have proven to be unsuitable for the near field. In contrast, we propose a novel, joint calibration approach for optical RGB-D sensors and MIMO radars that is designed to operate in the radar's near-field range, within decimeters from the sensors. Our pipeline consists of a bespoke calibration target, allowing for automatic target detection and localization, followed by the spatial calibration of the two sensor coordinate systems through target registration. We validate our approach using two different depth sensing technologies from the optical domain. The experiments show the efficiency and accuracy of our calibration for various target displacements, as well as its robustness of our localization in terms of signal ambiguities.

翻译：尽管MIMO雷达日益受到关注，但其与光学传感器协同利用互补优势的应用至今仍局限于远场场景，这是由于近场中传感器相互标定带来的挑战。实际上，自动驾驶领域大多数相关方法都采用基于角反射器的目标标定方法，而这类方法被证实不适用于近场环境。为此，我们提出一种适用于光学RGB-D传感器与MIMO雷达的新型联合标定方法，该方法专门设计在雷达近场范围（距传感器分米级内）运行。我们的流程包含定制化标定靶标，可实现自动目标检测与定位，进而通过目标配准完成两个传感器坐标系统的空间标定。我们采用两种不同光学深度传感技术验证该方法，实验表明该标定方法在不同目标位移条件下具备高效性与准确性，同时在信号模糊度方面展现出定位鲁棒性。