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Structured illumination surface profiling and ranging systems and methods

  • US 4,948,258 A
  • Filed: 06/27/1988
  • Issued: 08/14/1990
  • Est. Priority Date: 06/27/1988
  • Status: Expired due to Fees
First Claim
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1. A structured illumination method for determining characteristics of a surface which comprises:

  • projecting a beam of collimated rays from a ray source along a longitudinal axis,converting said beam into a divergent array of spaced dots of said rays in a predetermined pattern by passage of said beam through a holographic grating that intersects said longitudinal axis,projecting at least a portion of said divergent array of spaced dots onto a test surface remote from said grating a distance of Rp +dR,forming an image of the pattern of dots reflected from said test surface in recorder means that substantially intersects said longitudinal axis at a distance RF +dR along said axis from said test surface, with the proviso that Rp shall not equal RF,projecting a similar divergent array of spaced dots onto a datum surface remote from said grating a distance of Rp,forming an datum image of the pattern of dots reflected from said datum surface in recorder means that substantially intersects said longitudinal axis at a distance RF along said axis from said test surface,comparing the positions of said dots in said test image to the positions of the respective dots in said datum image to obtain values of the displacements of individual dots in said test image from the respective individual dots in said datum image, andusing said individual dot displacement values to determine one or more characteristics of said surface.

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