Overview of photon-counted three-dimensional imaging and related applications

Due to its detailed spatial mapping capability, three-dimensional (3D) imaging has became an indispensable tool for numerous scientific applications, including medical diagnostics, industrial inspection, autonomous navigation, environmental monitoring, etc. Conventional 3D imaging techniques often suffer from limitations such as poor resolution,and sensitivity, especially in low-light or photon-starved imaging conditions. A photon-counted imaging (PCI) system is often preferred to overcome this limitation. It is known that PCI systems leverage photon detection techniques to capture high-resolution 3D spatial information with exceptional sensitivity and resolution. To achieve this, single-photon detectors are used to count/detect (typically from single to a few hundred) photons from extremely low light level imaging conditions. This paper provides a comprehensive overview of PCI-based 3D imaging systems aimed at overcoming the limitations of the conventional 3D imaging systems. In addition to this, we also discuss some of the add-on applications of PCI systems, including information security, denoising, and resolution enhancement. This article comprises three major sections with four topics to provide an overview of recent research activities using photon-counted imaging systems.