US5352878A
Expired / Lapsed
US
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Method and apparatus for decoding bar code symbols using independent bar and space analysis
Assignee: United Parcel Service of America Inc
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Filing: 1993-01-29
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Granted: 1994-10-04
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Expires: 2013-01-29
Abstract
Abstract A bar code reader decodes a bar code symbol, one character at a time, by analyzing the spaces of each character independently from the bars of each character. The reader determines the widths of each space and each bar. The reader then determines a space-width threshold based on the widths of the spaces and a bar-width threshold based on the widths of the bars. The reader then classifies each space as being either narrow or wide by comparing each space to the space-width threshold. The reader also classifies each bar as being either narrow or wide by comparing each bar to the bar-width threshold. The reader then decodes the character according to the narrow/wide classifications.
Inventors
- 👤 Christopher E. Smith
- 👤 Mihael Klancnik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:47
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/14; G06K7/1404; G06K7/1439; G06K7/1443; G06K7/10544; G06K7/10821; G06K7/10851; G06K7/146; G06K7/1465; G06K7/1486
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
116 words
A method for decoding a character of a bar code symbol, wherein said character comprises one or more spaces and one or more bars, comprising the steps of: (a) scanning said symbol to determine the widths of said spaces and the widths of said bars; (b) determining a space-width threshold in accordance with said widths of said spaces; (c) determining a bar-width threshold in accordance with said widths of said bars, wherein said space-width threshold is different from said bar-width threshold; (d) comparing each of said spaces to said space-width threshold; (e) comparing each of said bars to said bar-width threshold; and (f) decoding said character in accordance with said comparisons of steps (d) and (e).
Claim 2
Independent Claim
116 words
A method for decoding a character of a bar code symbol, wherein said character comprises one or more spaces and one or more bars, comprising the steps of: (a) scanning said symbol to determine the widths of said spaces and the widths of said bars; (b) determining a space-width threshold in accordance with said widths of said spaces; (c) determining a bar-width threshold in accordance with said widths of said bars, wherein said space-width threshold is different from said bar-width threshold; (d) comparing each of said spaces to said space-width threshold; (e) comparing each of said bars to said bar-width threshold; and (f) decoding said character in accordance with said comparisons of steps (d) and (e).
Claim 3
Dependent Claim
95 words
The method of claim 1, wherein: said space-width threshold is the average of the widest of said spaces and the narrowest of said spaces; said bar-width threshold is the average of the widest of said bars and the narrowest of said bars; step (d) comprises the step of comparing each of said spaces to said space-width threshold to determine whether each of said spaces is narrow or wide; and step (e) comprises the step of comparing each of said bars to said bar-width threshold to determine whether each of said bars is narrow or wide.
Claim 4
Dependent Claim
24 words
The method of claim 1, wherein said bar code symbol is a Code 39 symbol and said character comprises four spaces and five bars.
Claim 5
Dependent Claim
27 words
The method of claim 1, wherein said bar code symbol is an Interleaved Code 2 of 5 symbol and said character comprises five spaces and five bars.
Claim 6
Dependent Claim
52 words
The method of claim 1, wherein said bar code symbol is in a pixel image, and step (a) comprises the steps of: (1) generating a composite signal in accordance with said symbol; and (2) determining said widths of said spaces and said widths of said bars in accordance with said composite signal.
Claim 7
Dependent Claim
61 words
The method of claim 1, wherein said bar code symbol is in a pixel image, and step (a) comprises the steps of: (1) generating a whitening gradient signal and a blackening gradient signal in accordance with said symbol; and (2) determining said widths of said spaces and said widths of said bars in accordance with said whitening and blackening gradient signals.
Claim 8
Dependent Claim
38 words
The method of claim 1, wherein said bar code symbol is in a binary pixel image and further comprising the step of locating said symbol in said image using byte-based searching for a quiet zone of said symbol.
Claim 9
Dependent Claim
40 words
The method of claim 1, wherein said bar code symbol is in a binary pixel image and further comprising the step of locating said symbol in said image using byte-based searching for a plurality of bright/dark transitions of said symbol.
Claim 10
Independent Claim
125 words
An apparatus for decoding a character of a bar code symbol, wherein said character comprises one or more spaces and one or more bars, comprising: (a) means for scanning said symbol to determine the widths of said spaces and the widths of said bars; (b) means for determining a space-width threshold in accordance with said widths of said spaces; (c) means for determining a bar-width threshold in accordance with said widths of said bars, wherein said space-width threshold is different from said bar-width threshold; (d) means for comparing each of said spaces to said space-width threshold; (e) means for comparing each of said bars to said bar-width threshold; and (f) means for decoding said character in accordance with said comparisons of means (d) and (e).
Claim 11
Independent Claim
125 words
An apparatus for decoding a character of a bar code symbol, wherein said character comprises one or more spaces and one or more bars, comprising: (a) means for scanning said symbol to determine the widths of said spaces and the widths of said bars; (b) means for determining a space-width threshold in accordance with said widths of said spaces; (c) means for determining a bar-width threshold in accordance with said widths of said bars, wherein said space-width threshold is different from said bar-width threshold; (d) means for comparing each of said spaces to said space-width threshold; (e) means for comparing each of said bars to said bar-width threshold; and (f) means for decoding said character in accordance with said comparisons of means (d) and (e).
Claim 12
Dependent Claim
93 words
The apparatus of claim 9, wherein: said space-width threshold is the average of the widest of said spaces and the narrowest of said spaces; said bar-width threshold is the average of the widest of said bars and the narrowest of said bars; means (d) comprises means for comparing each of said spaces to said space-width threshold to determine whether each of said spaces is narrow or wide; and means (e) comprises means for comparing each of said bars to said bar-width threshold to determine whether each of said bars is narrow or wide.
Claim 13
Dependent Claim
24 words
The apparatus of claim 9, wherein said bar code symbol is a Code 39 symbol and said character comprises four spaces and five bars.
Claim 14
Dependent Claim
27 words
The apparatus of claim 9, wherein said bar code symbol is an Interleaved Code 2 of 5 symbol and said character comprises five spaces and five bars.
Claim 15
Dependent Claim
53 words
The apparatus of claim 9, wherein said bar code symbol is in a pixel image, and means (a) comprises: (1) means for generating a composite signal in accordance with said symbol; and (2) means for determining said widths of said spaces and said widths of said bars in accordance with said composite signal.
Claim 16
Dependent Claim
62 words
The apparatus of claim 9, wherein said bar code symbol is in a pixel image, and means (a) comprises: (1) means for generating a whitening gradient signal and a blackening gradient signal in accordance with said symbol; and (2) means for determining said widths of said spaces and said widths of said bars in accordance with said whitening and blackening gradient signals.
Claim 17
Dependent Claim
37 words
The apparatus of claim 9, wherein said bar code symbol is in a binary pixel image and further comprising means for locating said symbol in said image using byte-based searching for a quiet zone of said symbol.
Claim 18
Dependent Claim
39 words
The apparatus of claim 9, wherein said bar code symbol is in a binary pixel image and further comprising means for locating said symbol in said image using byte-based searching for a plurality of bright/dark transitions of said symbol.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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