  3D imaging is increasingly impacting areas such as space, defense,
automation, medical and automotive industries. The most well-known optical 3D
imaging systems are LIDAR systems that rely on Time of Flight (ToF)
measurement. The depth resolution of the LIDAR systems is limited by the rise
time of the illumination signal, bandwidth of the detector systems, and the
signal-to-noise ratio. The focal gradients can be utilized to obtain 3D images
from 2D camera captures. In this study, we combine the basic LIDAR techniques
with a physical measurement of focal gradient changes that are caused by the
depth of field, to obtain a high-resolution 3D image using spatially separated
single-pixel detectors. The system that we introduce here enables depth
resolution that goes beyond the rise time of the incident laser pulse.
