Fig. 1.

Long-range NLOS imaging experiment. (A) An aerial schematic of the NLOS imaging experiment over a (standoff distance of) 1.43-km free-space link, in which the setup is placed at A and the hidden scene is placed at B. (The geographic image is from Google Earth $\text{©}$2020 Google.) (B) The optical setup of the NLOS imaging system, which consists of two synchronized telescopes for transmitter and receiver. A laser followed by galvo system and lenses are used for transmitting light pulses, while an InGaAs/InP SPAD together with a galvo system is used for collecting and detecting photons and recording their TOF information. (C) Schematic of the hidden scene in a room with a dimension size of 2 m$\times$1 m. (D) An actual photograph of the NLOS imaging setup. (E and F) Zoomed-out and zoomed-in photographs of the hidden scene taken at location A, where only the visible wall can be seen. (G) Photograph of the hidden object, taken at the room located at B.