Summary
A passive three-dimensional (3D) imager estimates the distance of objects from photographs captured without emitting light into the environment. Compared with active 3D technologies such as Light Detection and Ranging (LiDAR), passive 3D imaging offers important advantages in covertness, energy efficiency, and hardware simplicity, making it particularly attractive for applications in national defense, scientific exploration, robotics, and wearable devices. Despite substantial progress in both hardware and software, existing passive 3D imagers remain inherently limited by a short operating rang
