Method and apparatus for reading bar code under rapidly changing scanning speed conditions
First Claim
1. A method for reading bar code information at varied scanning speeds, wherein the information is contained in selected portions of the bar code, the portions being defined by respective transitions, comprising:
- generating the stream of pulses whose period is a unit measurement distance that is an inverse function of the scanning speed; and
determining the number of pulses which occur within the unit measurement distance to identify the information.
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Accused Products
Abstract
A bar code reader system includes a stream of pulses whose period is a function of the scan speed of the reader as it scans the bars and spaces of a bar code symbol. Transition pulses are supplied which identify the boundaries of the bars and spaces. The tach pulses which occur between transition pulses are counted, loaded into memory, and are read from memory via microprocessor means, whereby the widths of the bars and spaces are determined. The sequence of the bar and space data is decoded to yield the bar code encoded numbers.
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Citations
38 Claims
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1. A method for reading bar code information at varied scanning speeds, wherein the information is contained in selected portions of the bar code, the portions being defined by respective transitions, comprising:
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generating the stream of pulses whose period is a unit measurement distance that is an inverse function of the scanning speed; and determining the number of pulses which occur within the unit measurement distance to identify the information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for reading a bar code symbol with changing scanning speed wherein information is contained in wide and narrow bars and spaces of the bar code symbol, comprising:
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generating a stream of pulses at a rate indicative of the scanning speed; detecting the transitions between bars and spaces; and determining the number of pulses which occur between transitions to establish whether the number of pulses correspond to wide or narrow bars and spaces. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A system for recovering information encoded in a bar code symbol by scanning the latter with scanner means at scanning speed, said symbol containing data cells formed of wide and narrow bars whose scan distances in time are a function of the scanning speed, comprising;
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means for generating a stream of pulses whose period is a function of the relative rate of movement between the scanner means and the bar code symbol; means for representing the width of a data cell in terms of the number of pulses which occur therein; and means for establishing whether the number of pulses which occur during the data cell represent a wide or a narrow bar. - View Dependent Claims (16, 17)
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18. A system for recovering the information encoded in bars of a bar code symbol scanned by scanner means at a given speed, comprising:
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means for generating a stream of pulses whose period is a function of the scanning speed; means for detecting bar transitions; means for counting the pulses which occur between successive transitions; memory means for storing the successive count values obtained between successive transitions; and means for determining if the successive count values are indicative of wide or narrow bars. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. In a bar code reader/processor system having microprocessor means, wherein information is encoded in the specific sequence of wide and narrow bars and spaces of a bar code symbol, and wherein the symbol is scanned by scanner means to supply a data signal, a reading system comprising:
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means for generating a stream of pulses whose period in time is a function of the relative rate of movement between the scanner means and bar code symbol; means coupled to the scanner means for detecting bar/space and space/bar transitions in the data signal; counter means for counting the number of pulses which occur between successive transitions; memory means for storing the successive numbers of pulses counted during successive durations as data bytes; and means including the microprocessor means for determining if the stored data bytes represent wide or narrow bars or spaces. - View Dependent Claims (29, 30, 31, 32, 33)
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34. A system for identifying cassettes in a multiple cassette X,Y bin array, the apparatus including bar code symbols on each cassette for identifying same, an optical scanner movable in X-axis and Y-axis directions for supplying bar/space data signals associated with each of the cassettes as they are scanned in the X-axis direction by the optical scanner at a changing speed, comprising:
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tach means for supplying X-axis tach pulses indicative of the rate of optical scanner movement past a cassette in the X-axis direction; means coupled to the optical scanner for detecting transitions in the bar/space data signals; counter means coupled to the tach means for providing data bytes representing the numbers of X-axis tach pulses which occur between successive transitions and also whether the respective data byte corresponds to a bar or a space; memory means coupled to the counter means for storing successive data bytes; means coupled to the memory means for determining if the data byte is a bar or space and for determining the respective widths of the bars and spaces represented by the data bytes; and means for decoding the sequence of the bar and space widths to identify the respective cassette. - View Dependent Claims (35, 36, 37, 38)
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Specification