초록 ▼

A three-dimensional imaging system includes a two-dimensional array of pixel light sensing detectors and dedicated electronics and associated processing circuitry fabricated on a common IC using CMOS fabrication techniques. In one embodiment, each detector has an associated high speed counter that a

A three-dimensional imaging system includes a two-dimensional array of pixel light sensing detectors and dedicated electronics and associated processing circuitry fabricated on a common IC using CMOS fabrication techniques. In one embodiment, each detector has an associated high speed counter that accumulates clock pulses in number directly proportional to time of flight (TOF) for a system-emitted pulse to reflect from an object point and be detected by a pixel detector focused upon that point. The TOF data provides a direct digital measure of distance from the particular pixel to a point on the object reflecting the emitted light pulse. In a second embodiment, the counters and high speed clock circuits are eliminated, and instead each pixel detector is provided with a charge accumulator and an electronic shutter. The shutters are opened when a light pulse is emitted and closed thereafter such that each pixel detector accumulates charge as a function of return photon energy falling upon the associated pixel detector. The amount of accumulated charge provides a direct measure of round-trip TOF. In either embodiment, the collection of TOF data permits reconstruction of the three-dimensional topography of the light-reflecting surface of the object being imaged. The CMOS nature of the array permits random-order readout of TOF data if desired. Using a light source of a known wavelength and filtering out incoming light of other wavelengths permits use of the system with or without ambient light.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method to determine distance Z within resolution .DELTA.Z between at least one pixel detector and a target less than about 100 m distant, the method comprising the following steps:(a) disposing said at least one pixel detector so as to detect optical energy reflected

[ What is claimed is:] [1.]1. A method to determine distance Z within resolution .DELTA.Z between at least one pixel detector and a target less than about 100 m distant, the method comprising the following steps:(a) disposing said at least one pixel detector so as to detect optical energy reflected from said target, each said pixel detector having a pixel integration delay time exceeding 2.multidot..DELTA.Z/C, where C is speed of light, and for each said pixel detector disposing an associated pixel time interval counter;(b) illuminating said target at time t0 with at least a first pulse of optical energy from an energy source;(c) starting each said pixel time interval counter at said time t0 to count a clock signal operating at frequency at least about C/(2.multidot..DELTA.Z);(d) halting each said pixel time interval counter when an associated said pixel detector detects optical energy reflected from said target resulting from said first pulse; wherein detection time for said pixel detector includes actual time of flight (TOF) from said energy source to said target to said pixel detector, as well as pixel integration delay time for said pixel detector; and(e) removing said pixel integration delay time on a per pixel detector basis to obtain said actual TOF, whereby said distance Z is obtained.