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Fixed pattern noise compensation method and apparatus

  • US 20080143855A1
  • Filed: 11/30/2007
  • Published: 06/19/2008
  • Est. Priority Date: 03/28/1997
  • Status: Active Grant
First Claim
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1. A method for configuring an imaging system in a setup mode of operation so that in a run mode of operation said imaging system compensates image signals generated by said imaging system for fixed pattern noise, said imaging system having an image sensor including a monochrome two dimensional pixel array and being configured to run a bar code decoding application, said method comprising the steps of:

  • exposing said pixel array to a scene having a known radiance;

    capturing a predetermined number of image signal frames of said known radiance scene and finding a column white value for each column of said pixel array when said each frame is captured, wherein said finding step includes the step of discarding a predetermined number of pixel values in at least one column based on gray scale values of said pixel values;

    averaging said column white values to determine an average column white value for each column of said pixel array;

    comparing said each average column white value to a predetermined reference value for each column, and therefrom determining a correction value for each column of said array; and

    storing said each correction value into a storage location for retrieval by said imaging system when said imaging system processes image signals from said image sensor in said run mode of operation.

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