The goal of non-line-of-sight (NLOS) imaging is to image objects occluded
from the camera's field of view using multiply scattered light. Recent works
have demonstrated the feasibility of two-bounce (2B) NLOS imaging by scanning a
laser and measuring cast shadows of occluded objects in scenes with two relay
surfaces. In this work, we study the role of time-of-flight (ToF) measurements,
\ie transients, in 2B-NLOS under multiplexed illumination. Specifically, we
study how ToF information can reduce the number of measurements and spatial
resolution needed for shape reconstruction. We present our findings with
respect to tradeoffs in (1) temporal resolution, (2) spatial resolution, and
(3) number of image captures by studying SNR and recoverability as functions of
system parameters. This leads to a formal definition of the mathematical
constraints for 2B lidar. We believe that our work lays an analytical
groundwork for design of future NLOS imaging systems, especially as ToF sensors
become increasingly ubiquitous.

本篇研究探讨二次反射非直视成像在多路复用照明下的飞行时间测量对减少转发表面、提高空间分辨率的及时收集和图像恢复具有怎样的作用和贸易关系。 相关参数研究表明，时间分辨率、空间分辨率和屏幕截图数之间需要平衡，并且引出了 2B lidar 的数学约束的形式定义。 这一研究为未来的非直视成像系统的设计奠定了数学基础，特别是随着 ToF 传感器变得越来越普及。