Distance measuring apparatus

• US 5,552,893 A
• Filed: 09/15/1994
• Issued: 09/03/1996
• Est. Priority Date: 09/17/1993
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Akasu, Masahira
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/306,327
• Time in Patent Office: 719 Days
• Field of Search: 356/5.01, 356/5.03, 356/4.01
• US Class Current: 356/5.01
• CPC Class Codes: G01C 3/00 Measuring distances in line of sight; Optical rangefinders tapes, chains or wheels for measuring length G01B3/00; active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves, G01S17/48
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

A distance measuring apparatus comprises projection means, light receiving means, computation means and scanning means. The projection means projects plural laser beams in different directions. The light receiving means receives the light reflected from each of objects in respective beam directions. The computation means computes the distances to the objects on the basis of the reflected light. And the scanning means sequentially changes the projecting directions of said plural laser beams.

Claims

1. A distance measuring apparatus comprising:

projection means for projecting plural laser beams in different directions;

light receiving means for receiving the light reflected from each of objects in respective beam directions;

computation means for computing the distances to the objects on the basis of the reflected light; and

scanning means for sequentially changing the projecting directions of said plural laser beams such that a scan having a resolution of field of view of 0.5 degrees or less is performed.

2. A distance measuring apparatus according to claim 1, wherein the plural laser beams are scanned in the same direction as their alignment directions.

3. A distance measuring apparatus according to claim 1, wherein the plural laser beams are scanned in the directions orthogonal to their alignment directions.

4. A distance measuring apparatus according to claim 2, wherein the plural laser beams are projected in different separated directions and the scanning of the respective beams is performed in such a manner that the intervals between them are interpolated.

5. A distance measuring apparatus according to claim 2, wherein the plural laser beams are projected in different separated directions, the scanning of the respective beams is performed in such a manner that the intervals between them are interpolated, and thereafter the scanning is shifted to the outermost adjacent position of the next scanning state.

6. A distance measuring apparatus according to claim 2, wherein every interval between two adjacent laser beams of N laser beams is divided into a number of intervals which is less than the square of N, other than integer-times of any prime numbers less than N and other than 1, and wherein the scanning is performed in such a manner that the shift of said divided N intervals is made as one scanning, where N is a number of laser beams.