Clark Neil Smith
Accountancy in Salt Lake City, UT

4144449, Mar 13, 1979

Jul 8, 1977

5/814060

Buddy K. Funk - Bountiful UT
Clark L. Smith - Salt Lake City UT

Sperry Rand Corporation - New York NY

G01D 2104

250221

Apparatus for detecting the position of a passive object includes a generally rectangular frame having an open interior, a source on the frame for emitting light through the frame interior from three sides thereof, a pair of linear image detectors, such as charge-coupled devices, being respectively mounted on the frame at two corners thereof being located at opposite ends of a fourth side thereof and adjacent respective opposite ends of the light source, a pair of aperture-defining devices located at the two frame corners between the detectors and the interior of the frame for configuring coincident fields of light from the frame interior for the detectors to view, and control circuitry connected to the detectors. Each of the detectors is capable of receiving its respective field of light from the frame interior and sensing interruption of light at any location within the field. The control circuitry is responsive to any interruption sensed by the detectors for determining where in the frame interior illuminated by the coincident fields of light the interruption occurred and thereby the position of the passive object which caused the interruption.