Topographic comparator

US4294544A · kind A · utility

Inventors

• Bruce R. Altschuler · Odenton, US
• John Taboada · San Antonio, US
• Martin D. Altschuler · Wallingford, US

Key dates

• Filing date: Aug 3, 1979
• Grant date: Oct 13, 1981
• Expiry date: Aug 3, 1999

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B11/022
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Three-dimensional (3-D) topographic data defining a remote surface in terms of the 3-D positions of M.times.N sample points on that surface may be obtained by (1) illuminating the scene with an array of M.times.N (simultaneous) laser beams, (2) sequencing the array of laser beams through a series of mathematical patterns (space coding) by means of a programmable electro-optic shutter, (3) recording by an imaging device the illumination reflected from the surface during the projection of each mathematical pattern, (4) analyzing the images to obtain the three-dimensional locations of each of the M.times.N illuminated points on the surface which are visible to the camera or imaging device, and (5) determining which of the laser beams in the array are not visible to the imaging device. (N and M are any positive integers consistent with the device proposed; typically M=N=128, so that M.times.N=16384 points.) Mechanization for rapid three-dimensional mapping of the surface involves an array of laser beams illuminating the surface, a programmable electro-optic shutter to switch on and off subsets of laser beams in the array and thereby to input the space code projected on the surface, a (…