Analysis of non-line-of-sight imaging characteristics based on laser range-gated imaging

Laser range-gated imaging systems can obtain the images of targets hidden around a corner by using an intermediary reflective surface with certain specular reflection characteristics. This imaging mode is called non-line-of-sight imaging. The target signal irradiance and disturbance radiation on the photo-detector of a non-line-of-sight imaging system are analyzed based on the modeling of an intermediary reflective surface, and an image contrast model of a non-line-of-sight imaging system is constructed. The effects of the reflective characteristics of an intermediary reflective surface and the distance between the intermediary reflective surface and the target or the detector on the image quality are analyzed in terms of the parameters of a typical non-line-of-sight imaging system. The simulation results show that a laser range-gated imaging system is indispensable for non-line-of-sight imaging with commonly used intermediary reflective surfaces without significant specular reflection characteristics, and the distance of the intermediary reflective surface from the target has a significant effect on the non-line-of-sight imaging. When the locations of detector and target are fixed, the non-line-of-sight imaging system can hardly identify the target if the intermediary reflective surface is closer to the target. In practice, the performance of the non-line-of-sight imaging system can be maximized using an appropriate usage strategy.