Conventional sensor systems record information about directly visible
objects, whereas occluded scene components are considered lost in the
measurement process. Non-line-of-sight (NLOS) methods try to recover such
hidden objects from their indirect reflections - faint signal components,
traditionally treated as measurement noise. Existing NLOS approaches struggle
to record these low-signal components outside the lab, and do not scale to
large-scale outdoor scenes and high-speed motion, typical in automotive
scenarios. In particular, optical NLOS capture is fundamentally limited by the
quartic intensity falloff of diffuse indirect reflections. In this work, we
depart from visible-wavelength approaches and demonstrate detection,
classification, and tracking of hidden objects in large-scale dynamic
environments using Doppler radars that can be manufactured at low-cost in
series production. To untangle noisy indirect and direct reflections, we learn
from temporal sequences of Doppler velocity and position measurements, which we
fuse in a joint NLOS detection and tracking network over time. We validate the
approach on in-the-wild automotive scenes, including sequences of parked cars
or house facades as relay surfaces, and demonstrate low-cost, real-time NLOS in
dynamic automotive environments.

该研究使用多普勒雷达技术进行非直达测距，利用时序多普勒速度和位置信息进行 NLOS 检测与跟踪，成功实现对动态环境中隐藏物体的检测、分类和追踪，适用于大规模的汽车场景且成本低廉。

街角探测：使用多普勒雷达在野外进行非直射线探测和跟踪

Seeing Around Street Corners: Non-Line-of-Sight Detection and Tracking  In-the-Wild Using Doppler Radar

A remote-sensing system that can determine the position of hidden objects has
applications in many critical real-life scenarios, such as search and rescue
missions and safe autonomous driving. Previous work has shown the ability to
range and image objects hidden from the direct line of sight, employing
advanced optical imaging technologies aimed at small objects at short range. In
this work we demonstrate a long-range tracking system based on single laser
illumination and single-pixel single-photon detection. This enables us to track
one or more people hidden from view at a stand-off distance of over 50~m. These
results pave the way towards next generation LiDAR systems that will
reconstruct not only the direct-view scene but also the main elements hidden
behind walls or corners.

本研究设计了一种基于单激光照射和单像素单光子探测的长距离追踪系统，能够在 50m 的距离上追踪一个或多个隐藏在视野之外的人，为下一代 LiDAR 系统的发展铺平了道路。