Patent Number: 6,166,810

Title: Method and apparatus for determining distance

Abstract: A method and apparatus for precision distance measurement are provided to perform accurate measurement of distance to an object according to light spots formed on the light receiving surface of a detector even when multiple reflections are involved. A beam of light emitted from a light source and reflected from the object is focused on the viewing surface as light spots through an optical member. The focal position of a reflected beam of light is determined according to a focal position detection process. When there are peaks in a luminosity curve generated on the detector, prior to performing the focal position detection process, the peaks are separated into individual light spots and a correct light spot for deriving the precise distance is selected by a selection process.

Inventors: Nakayama; Joji (Tokyo, JP), Katayama; Atsushi (Tokyo, JP)

Assignee: Nippon Telegraph and Telephone Corporation

International Classification: G01B 11/02 (20060101); G01C 3/08 (20060101); G01B 011/24 ()

Expiration Date: 12/26/2013