Method and apparatus for scrambling and unscrambling bar code symbols
First Claim
1. Method of coding and decoding a bar code, said method comprising the steps of:
- forming a parallax panoramagram that is a lineticular dissection of said bar code, by scrambling said bar code in accordance with a graticule formed of a plurality of parallel contiguous focussing elements at a spatial frequency greater than the modular spatial frequency of said bar code;
providing a light transparent screen having a plurality of elongated parallel line elements including focussing surfaces disposed in common along a first surface of said screen, the spatial frequency of said line elements being matched to the spatial frequency of said focussing elements of said graticule;
positioning said panoramagram contiguous to the opposite surface of said screen with said line elements disposed substantially parallel to the lines in said lineticular dissection; and
examining said panoramagram through said screen.
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Abstract
Apparatus for and method of unscrambling a parallax panoramagram that is a lineticular dissection of a bar code formed by scrambling the bar code in accordance with a graticule formed of a plurality of parallel contiguous focussing elements disposed at a spatial frequency greater than the modular spatial frequency of the bar code. The method includes positioning said panoramagram contiguous to the opposite surface of a light transparent screen having a plurality of elongated parallel line elements including focussing surfaces disposed in common along a first surface of the screen, the spatial frequency of those line elements being matched to the spatial frequency of the focussing elements. Positioning is achieved so that the line elements are disposed substantially parallel to the lines in the lineticular dissection.
A beam of light is used to scan the panoramagram by moving the beam across said first surface of the screen transversely to the axes of the line elements, the beam having a cross-section dimension, where incident on the screen, not greater than the width of the line element. Light reflected from the scan of the beam across a registered panoramagram and screen, is converted into electrical signals representing an unscrambled version of the bar code.
53 Citations
26 Claims
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1. Method of coding and decoding a bar code, said method comprising the steps of:
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forming a parallax panoramagram that is a lineticular dissection of said bar code, by scrambling said bar code in accordance with a graticule formed of a plurality of parallel contiguous focussing elements at a spatial frequency greater than the modular spatial frequency of said bar code; providing a light transparent screen having a plurality of elongated parallel line elements including focussing surfaces disposed in common along a first surface of said screen, the spatial frequency of said line elements being matched to the spatial frequency of said focussing elements of said graticule; positioning said panoramagram contiguous to the opposite surface of said screen with said line elements disposed substantially parallel to the lines in said lineticular dissection; and examining said panoramagram through said screen. - View Dependent Claims (2, 3, 4, 5)
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6. Method of unscrambling a parallax. panoramagram that is a lineticular dissection of a bar code formed by scrambling said bar code in accordance with a graticule formed of a plurality of parallel contiguous focussing elements disposed at a spatial frequency greater than the modular spatial frequency of said bar code, said method comprising the steps of:
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providing a light transparent screen having a plurality of elongated parallel line elements including focussing surfaces disposed in common along a first surface of said screen, the spatial frequency of said line elements being matched to the spatial frequency of said focussing elements; positioning said panoramagram contiguous to the opposite surface of said screen with said line elements disposed substantially parallel to the lines in said lineticular dissection; producing a beam of light; scanning said panoramagram by moving said beam across said first surface of said screen transversely to the line axes of said line elements, said beam being produced with a cross-section dimension, where incident on said screen, not greater than the width of a line element; and detecting light reflected from the scan of said beam across a registered panoramagram and screen, and converting said reflected light into electrical signals representing an unscrambled version of said bar code. - View Dependent Claims (7, 8, 9, 10, 11)
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12. Apparatus for unscrambling a scrambled parallax panoramagram that is a lineticular dissection of a bar code, which panoramagram is formed by scrambling said bar code in accordance with a graticule having a plurality of parallel, contiguous, focussing elements disposed at a spatial frequency greater than the modular spatial frequency of said bar code, said apparatus comprising, in combination:
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a light transparent screen having a plurality of elongated parallel line elements having focussing surfaces disposed in common along one surface of said screen, the spatial frequency of said line elements being matched to the spatial frequency of said focussing elements; optical scanning means for producing a beam of light and being disposed with respect to said screen for scanning said beam across said first surface of said screen transversely to the line axes of said line elements, said beam, where incident on said screen, having a cross-section dimension not greater than the width of a line element; means for positioning said panoramagram contiguous to the opposite surface of said screen with said line elements disposed substantially parallel to the lines in said lineticular dissection; and means for detecting light reflected from the scan of said beam across a registered panoramagram and screen, and for converting said reflected light into electrical signals representing an unscrambled version of said bar code. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification