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METHOD OF SPECKLE-NOISE PATTERN REDUCTION AND APPARATUS THEREFOR BASED ON REDUCING THE SPATIAL-COHERENCE OF THE PLANAR LASER ILLUMINATION BEAM BEFORE IT ILLUMINATES THE TARGET OBJECT BY APPLYING SPATIAL PHASE MODULATION TECHNIQUES DURING THE TRANSMISSION OF THE PLIB TOWARDS THE TARGET

  • US 6,863,216 B2
  • Filed: 04/30/2002
  • Issued: 03/08/2005
  • Est. Priority Date: 03/24/1998
  • Status: Expired due to Fees
First Claim
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1. A method of reducing speckle-pattern noise at the image detection array of a planar laser illumination and imaging (PLIIM) based system, said method comprising the steps of:

  • (a) producing a planar laser illumination laser beam (PLIB) within a planar laser illumination and imaging (PLIIM) based system including an image detection array having image forming optics with a field of view (FOV) arranged in a coplanar relationship with said PLIB;

    (b) reducing the spatial-coherence of said planar laser illumination beam (PLIB) before said PLIB illuminates a target object, by applying a spatial phase modulation technique during the transmission of said PLIB towards the target, so that the object is illuminated with a spatially coherent-reduced planar laser illumination beam (PLIB) and numerous substantially different time-varying speckle-noise patterns are produced at said image detection array over the photo-integration time period thereof;

    (d) detecting said numerous substantially different time-varying speckle-noise patterns over said photo-integration time period; and

    (e) temporally averaging said detected speckle-noise patterns at said image detection array during said photo-integration time period thereof, thereby reducing the RMS power of observable speckle-noise patterns at said image detection array.

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