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Optical sensor for imaging an object

  • US 5,381,236 A
  • Filed: 08/10/1993
  • Issued: 01/10/1995
  • Est. Priority Date: 02/12/1991
  • Status: Expired due to Term
First Claim
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1. An optical sensor comprising:

  • a structured light source for producing a pattern of contrasting areas;

    a detector which comprises an array of detector elements having dimensions matched to the pattern produced by the light source;

    an optical system for projecting a primary image of the light source onto an object that is to be sensed and for forming a secondary image on the detector of the primary image thus formed on the object;

    adjustment means for adjusting at least part of the optical system to vary the focussing of the primary image on the object, such that when the primary image is in focus on the object, the secondary image on the detector is also in focus; and

    processing means for analyzing signals produced by the detector in conjunction with information on the adjustment of the optical system;

    wherein the structured light source is adjustable to interchange at least two positions of contrasting areas of the pattern produced by the light source and in that the processing means is arranged to analyze the secondary images received by the detector elements with the contrasting areas in the interchanged positions to determine those parts of the secondary images which are in focus on the detector and thereby determine the range of corresponding parts of the object which are thus in focus.

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