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Method of programmable digitization and bar code scanning apparatus employing same

  • US 5,286,960 A
  • Filed: 11/04/1991
  • Issued: 02/15/1994
  • Est. Priority Date: 11/04/1991
  • Status: Expired due to Term
First Claim
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1. A method of accurately reconstructing from a sampled analog signal bar-to-space and space-to-bar transition points in a symbol comprising the steps of:

  • accepting as input successive samples from an analog signal, said samples being representative of levels of reflectivity of a symbol being scanned;

    determining a white value associated with a space and a black value associated with a bar on said symbol;

    determining a threshold between said black value and said white value;

    determining from said input a preceding sample and a succeeding sample having values that bracket said threshold; and

    determining a transition point and an offset of said transition point from said preceding sample to define a first time interval therebetween by performing an interpolation that is limited to an interval between said preceding sample and said succeeding sample in the absence of upsampling.

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