Ink-spread compensated bar code symbology and compensation methods
First Claim
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1. A method of producing an ink-spread compensated variant of an existing optical code encodation scheme comprising the steps of:
- determining a pattern of printed areas and spaces in the existing encodation scheme for a data input;
the printed areas and spaces each having a respective length in at least one dimension as a function of a given unit length for encoding information; and
adding a predetermined length to the length of each space while the length of each printed area remains unchanged to produce a modified code symbol.
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Abstract
A method for producing an ink-spread compensated variant of an existing optical code encodation scheme, wherein the existing encodation scheme has printed areas and spaces having a length in at least one dimension being a function of a given unit length for encoding information. In the method, the pattern of printed areas and spaces for a given data input is determined and a given length is added to the length of each space while the length of the printed areas remains unchanged to enlarge the overall length of the resulting code symbol in the at least one dimension.
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Citations
24 Claims
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1. A method of producing an ink-spread compensated variant of an existing optical code encodation scheme comprising the steps of:
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determining a pattern of printed areas and spaces in the existing encodation scheme for a data input;
the printed areas and spaces each having a respective length in at least one dimension as a function of a given unit length for encoding information; and
adding a predetermined length to the length of each space while the length of each printed area remains unchanged to produce a modified code symbol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
dividing the encodation scheme into at least a first and a second set of data characters; and
the step of determining selecting the pattern from the second set, the different characters in the first and second sets providing an auto-discrimination feature to identify an ink-spread compensated code symbol.
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20. The method according to claim 1, further comprising the step of adding at least one auto-discrimination feature to the modified code symbol to enable a reader to determine that the modified code symbol is an ink-spread compensated variant for the decoding thereof.
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21. The method according to claim 20, further comprising the step of adding a data character pattern to the modified code symbol to identify the modified code symbol as an ink-spread compensated variant.
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22. The method according to claim 20, wherein code symbols generated according to the existing optical code encodation scheme have an existing first start pattern and an existing first stop pattern, the step of adding auto-discrimination comprising at least one of
(a) using a second start pattern in place of the existing first start pattern in the modified code symbol, and (b) using a second stop pattern in place of the existing stop pattern in the modified code symbol. -
23. The method according to claim 20, wherein code symbols generated according to the existing optical code encodation scheme have a first finder pattern and wherein the step of adding auto-discrimination comprises providing a second finder pattern in the modified code symbol in place of the first finder pattern.
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24. In a method for decoding an ink-spread compensated variant of an existing n, k bar encodation scheme produced in accordance with claim 23, the improvement comprising the steps of:
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discriminating that the bar code symbol is an ink-spread compensated variant and determining the amount of the added length;
normalizing the width of a character to add the total added length; and
varying the threshold for the spaces to compensate for the length added thereto.
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Specification