Close-range measurement of time of flight using parallax shift

Abstract

An optical sensing device includes a light source, which emits one or more beams of light pulses toward a target scene at respective angles about a transmit axis of the light source. A first array of single-photon detectors output electrical pulses in response to photons that are incident thereon. A second array of counters count the electrical pulses output during respective count periods by respective sets of one or more of the single-photon detectors. Light collection optics form an image of the target scene on the first array along a receive axis, which is offset transversely relative to the transmit axis, thereby giving rise to a parallax shift as a function of distance between the target scene and the device. Control circuitry sets the respective count periods of the counters, responsively to the parallax shift, to cover different, respective time intervals following each of the light pulses.