Single-photon computational 3D imaging at 45  km

Abstract

Single-photon light detection and ranging (lidar) offers single-photon sensitivity and picosecond timing resolution, which is desirable for high-precision three-dimensional (3D) imaging over long distances. Despite important progress, further extending the imaging range presents enormous challenges because only a few echo photons return and are mixed with strong noise. Here, we tackled these challenges by constructing a high-efficiency, low-noise coaxial single-photon lidar system and developing a long-range-tailored computational algorithm that provides high photon efficiency and good noise tolerance. Using this technique, we experimentally demonstrated active single-photon 3D imaging at a distance of up to 45 km in an urban environment, with a low return-signal level of ∼ 1 photon per pixel. Our system is feasible for imaging at a few hundreds of kilometers by refining the setup, and thus represents a step towards low-power and high-resolution lidar over extra-long ranges.

Full Waveform LiDAR for Adverse Weather Conditions

“…There is the issue of operating range, even in good weather. Photon counting LiDARS have high sensitivity, and combined with new developments in sparse modeling of scenes and very efficient scanning optics have been shown to work at long ranges [35], [104] but these are not (yet) suitable for automotive applications. In addition to issues of optical and computational efficiency, in general, the 3D reconstruction algorithms make simplifying assumptions, e.g.…”

Three-Dimensional Imaging via Time-Correlated Single-Photon Counting

“…After that, TCSPC began to be used in the field of laser ranging [13][14][15][16][17][18] and gradually developed to the direction of laser long-distance 3D imaging based on time-of-flight (TOF) algorithm [19][20][21][22][23][24][25][26]. Recently, Li et al achieved the imaging of targets 45 kilometers away [27]. Kirmani et al [28] and Xialin Liu et al [29] detected the first photon in TCSPC system to image the object.…”

“…In the general TCSPC system, the image result is greatly affected by environmental noise because of the ultra-high sensitivity of the single-photon detectors (SPD). Up to now, most of the research teams used the range-gated technology to decrease the impact of noise [20,24,27]. Besides, Kong et al used two Geiger-mode avalanche photodiodes and an AND gate to reduce false alarms caused by environmental noise [30].…”

How many photons does it take to form an image?

“…To overcome the shot noise one needs to use an intensity-squeezed light source 57,58 , however this potential advantage is only easy accessible in a low loss modality due to the low repetition rate of the squeezed light source, the sensing is performed in transmission rather than backscatter configuration. These considerations are important for applications such as LIDAR where efficient detection demands that we fully utilise the minimal information available from the sparse number of photons received by the detector 59,60 . Historically the question as to "how many photons does it take to form an image" would have been answered by considering the noise floor of the detector.…”