Method and apparatus for optimizing sub-pixel resolution in a triangulation based distance measuring device

  • US 5,905,567 A
  • Filed: 05/05/1997
  • Issued: 05/18/1999
  • Est. Priority Date: 03/25/1994
  • Status: Expired due to Term
First Claim
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1. An apparatus for optimizing stib-pixel resolution in a triangulation based target distance measuring device at a desired stand-off distance comprisesa laser light source projecting a light beam along a light beam axis so as to project a light spot onto a surface of a workpiece,a lens having an optical axis and a depth of focus dependent on said target distance, said lens for gathering reflected light from said light spot on said surface of said workpiece,a linear photodetector array of adjacent light detecting pixels, said array having a longitudinal array axis, said array for detecting light impinging said pixels and generating an output signal indicative of the position of said pixels being impinged by said light,said light beam axis, said optical axis, and said longitudinal array axis co-planar in a first plane,said lens imaging said reflected light across said array so as to impinge said array and form an image across said array, said output signal indicative of an intensity profile of said image impinging said array, said image defocused to a near-Scheimpflug condition so as to optimize said output signal from said array, whereby movement of said surface of said workpiece relative to said distance measuring device while said light spot is projected onto said surface causes corresponding movement of said image along said array.

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