Noise reduction techniques suitable for three-dimensional information acquirable with cmos-compatible image sensor ics

Abstract

A three-dimensional imaging system is fabricated on a single IC. The system includes a two-dimensional array of pixel light sensing detectors and dedicated electronics and associated processing circuitry, all preferably fabricated on a single IC using CMOS fabrication techniques. The system includes a detector array comprising a plurality of pixel photodiodes and photodiode circuits, wherein each pixel photodiode acquires delay time data and pulse brightness data simultaneously. The system emits an energy pulse at time t0 and a fraction of the energy is returned to the array by a target object. Photodiodes in the array output a brightness signal B(t) that is integrated. An elapsed time ET from t0 to when said B(t) attains a predetermined threshold value is determined, where the slope of B(t) is B/PW, where B is B(t) after integrating over a time equal to the emitted pulse width PW. Time-of-flight TOF representing time from t0 to when a photodiode begins to detect energy is determined, where TOF=ET−IT, where IT is proportional to PW/B. A system processor determines distance from the system to the target object, from TOF and the velocity of light, and can translate TOF into commands to control electronic devices.