Bar code signal digitizer adapted for signals from inverse bar codes
First Claim
1. A system for enabling a bar code reader for reading a direct bar code having bars of lower reflectivity than a background on which the bars are disposed to read inverse bar codes where the bars are of higher reflectivity than the background, which system comprises means for digitizing signals representing light returned when the code is scanned into a digitized bar code output having two states, one corresponding to the bars and the other corresponding to the background, means for restoring the output to one of said states, means for changing the state to which said restoring means restores the digitized bar code output when the inverse bar code is being digitized, thereby inhibiting a premature change of state at the onset of scanning, and means for inverting the states of said bar code digitized output when said inverse bar code is being digitized to provide a digitized output having like states, whether representing direct or inverse codes.
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Accused Products
Abstract
In order to prevent a digitizer which receives signals from a bar code reader which scans an inverse code (white bars on black background as opposed to a direct or normal code with black bars on white background) from improperly digitizing a white space as a black bar and also, if desired, to enable the digitizer to operate properly in digitizing signals from direct or inverse codes without switching the digitizer from direct to inverse digitizing mode by operator control, the digitizer is operated, automatically under computer control on different ones of a series of successive scans of the code, which are carried out until the code is successfully read, to provide an output, which is of different states when reading white sections and black sections of the code, and to be restored, respectively, to a state corresponding to the reading of a black section of the code and to a state corresponding to the reading of a white section of the code, when a direct code is to be digitized and when an inverse code is to be digitized. In effect, the output is prevented from being restored to a black representing state when a direct code is to be digitized and to a white representing state when an inverse code is to be digitized. In addition, the digitizer has circuitry for inverting the state of the digitized bar code output of the digitizer when inverse codes are digitized.
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Citations
9 Claims
- 1. A system for enabling a bar code reader for reading a direct bar code having bars of lower reflectivity than a background on which the bars are disposed to read inverse bar codes where the bars are of higher reflectivity than the background, which system comprises means for digitizing signals representing light returned when the code is scanned into a digitized bar code output having two states, one corresponding to the bars and the other corresponding to the background, means for restoring the output to one of said states, means for changing the state to which said restoring means restores the digitized bar code output when the inverse bar code is being digitized, thereby inhibiting a premature change of state at the onset of scanning, and means for inverting the states of said bar code digitized output when said inverse bar code is being digitized to provide a digitized output having like states, whether representing direct or inverse codes.
Specification