Passive non-line-of-sight imaging at 10 meters

Non-line-of-sight (NLOS) imaging seeks to reconstruct scenes obscured from the direct line of sight by capturing indirect light encoded on an intermediate visible surface. Unlike active approaches that rely on expensive and dedicated systems, passive methods utilize only a low-cost digital camera to record the light signal encoded on visible surface. However, the imaging range of passive NLOS techniques is typically constrained to the meter scale due to a low signal-to-background ratio (SBR), resulting from significant light attenuation over long propagation distances and the presence of strong ambient background illumination. In this work, we present an approach that combines pattern-based calibration with low-rank matrix decomposition for noise suppression, enabling both enhancement of the NLOS signal and separation of ambient background contributions. We experimentally demonstrate passive NLOS imaging at a 10 m wall-to-camera distance and a 4.5 m wall-to-object distance, achieving centimeter-scale resolution at an SBR as low as -13 dB, outperforming previous works. Our results highlight the significant potential for practical passive NLOS applications.