Study on BRDF Scattering Characteristics of Relay Wall in Non-Line-of-Sight Imaging Based on Time-gated SPAD Array

Non-line-of-sight imaging is a rapidly developing imaging technology aimed at practical applications. The imaging mode based on a SPAD array has advantages such as staring imaging and lightweight equipment compared with others. This study analyzes a non-line-of-sight imaging method based on a time-gated SPAD array, focusing on the scattering characteristics of the BRDF of the relays in the time-gated SPAD array mode of non-line-of-sight imaging and its impact on imaging. The Cook-Torrance model was selected to model and analyze the BRDF scattering characteristics of typical building materials that serve as relays. The BRDF data of three typical building materials, namely black glossy tiles, white matte tiles, and black protective shields, were measured. The RANSAC algorithm was used to eliminate measurement outliers, and a genetic algorithm was employed to obtain the characteristic parameters of the model. This study validates the effectiveness of describing the BRDF scattering characteristics of materials using characteristic parameters, which can lay an important foundation for further research on time-gated SPAD-array-based non-line-of-sight imaging.