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Exposure control method for use with optical readers

  • US 20020179713A1
  • Filed: 07/22/2002
  • Published: 12/05/2002
  • Est. Priority Date: 12/18/1995
  • Status: Abandoned Application
First Claim
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1. A method for controlling an exposure period of an optical reader, said reader having an image sensor including a pixel array comprising a plurality of pixels, said method comprising the steps of:

  • generating an image sensor signal that varies in accordance with the intensity on light incident of said pixel array;

    generating an illumination signal that varies in accordance with a time averaged value of said image sensor signal;

    establishing an initial exposure control variable, said exposure control variable determining the duration of said exposure period;

    detecting whether said illumination signal is inside or outside of an illumination window bounded by predetermined maximum and minimum illumination values;

    increasing said exposure control variable if said illumination signal is below said predetermined minimum illumination value; and

    decreasing said exposure control variable if said illumination signal is above said predetermined maximum illumination value.

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