Abstract: An improved three-dimensional imaging system for imaging an object having a number of resolvable elements including: an amplitude modulated radiation source for transmitting radiation to the object; at least one photoelectric image detector; a gating circuit for synchronously enabling at least one of the detectors during at least three portions of the period of the modulated radiation source for detecting radiation reflected from the object; and a 3-dimensional image computer having a first routine for calculating the phase angle between the transmitted radiation and the reflected radiation and a second routine, responsive to the calculated phase angle, for calculating the range of the number of elements of the object with respect to each other.

Abstract: An optical measurement system includes: at least one optical beam transmitter; at least one optical beam detector for receiving the optical beam from the transmitter; modulation means for modulating the intensity of the transmitted optical beam; processor means for detecting the fractional and integer phase difference between the intensity modulation of the transmitted beam and the beam received by the receiver; and a calculator device for converting the integer and fractional phase difference into a distance between the transmitter and detector.