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Distance measuring apparatus

  • US 6,657,705 B2
  • Filed: 06/20/2002
  • Issued: 12/02/2003
  • Est. Priority Date: 06/20/2001
  • Status: Active Grant
First Claim
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1. A distance measuring apparatus comprising:

  • scanning and applying means for applying a forward laser beam to a prescribed detection area, and controlling the forward laser beam to scan the detection area along a scanning direction;

    reflected light detecting means for receiving an echo laser beam caused by reflection of the forward laser beam at an object, the reflected light detecting means including a photodetector array in which a plurality of photo detecting elements are arranged in at least one of the scanning direction and a direction perpendicular to the scanning direction, the photodetector array having a visual field wider than a visual field corresponding to the detection area;

    changing and selecting means for selecting at least one among the photo detecting elements as an effective element and changing the effective element from one to another in response to a direction of the application of the forward laser beam;

    time difference measuring means for measuring a time difference between a moment of the application of the forward laser beam by the scanning and applying means and a moment of the reception of the echo laser beam by the reflected light receiving means;

    distance calculating means for calculating one of (1) a distance to the object and (2) a physical quantity indicative of the distance to the object on the basis of the time difference measured by the time difference measuring means; and

    correspondence relation grasping means for identifying at least one among the photo detecting elements which receives an echo laser beam corresponding to the forward laser beam applied in a specified direction, and for grasping an actual correspondence relation between directions of the application of the forward laser beam and the photo detecting elements receiving corresponding echo laser beams on the basis of a relation between the identified photo detecting element and the specified direction;

    wherein the changing and selecting means includes means for selecting at least one among the photo detecting elements as an effective element and changing the effective element from one to another in response to the direction of the application of the forward laser beam according to the actual correspondence relation grasped by the correspondence relation grasping means.

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