EP0431264A2
Expired / Lapsed
EP
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Method and apparatus for decoding bar codes from multiple scans
Assignee: Symbol Technologies LLC
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Filing: 1990-08-24
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Granted: —
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Expires: 2010-08-24
Abstract
Abstract A method for reading bar code symbols which enables legitimate characters recognized by the code in use to be derived from a plurality of scans corresponding to illegitimate characters not recognized by the code in use is disclosed. The method includes the steps of storing representations of the bar code symbol which cannot be decoded to produce legitimate character(s). One of the representations is improved, or corrected, using another representation, and an attempt is made at decoding the corrected representation to produce a legitimate character. If the decoding attempt is not successful, further corrections are made in order to provide a representation which may be decoded to produce a legitimate character.
Inventors
- 👤 David P. Goren
- 👤 Theodosios Pavlidis
- 👤 Glenn Spitz
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 14:45
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/14; G06K7/1404; G06K7/146; G06K7/1491; G06K7/01; G06K7/016; G06K7/0166
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
140 words
In a method for decoding bar code symbols in which a bar code reader and associated components scan a bar code symbol having a succession of linear elements of different light reflectivity, produce a representation of the symbol and attempt to decode the representation of the symbol in order to produce a legitimate character message containing legitimate characters which are decodable, all non-decodable characters being illegitimate, the improvement comprising the steps of: storing a first representation of the bar code symbol corresponding to a first scan path through said symbol; storing a second representation of said bar code symbol corresponding to a second scan path through said symbol; and replacing at least one element of an illegitimate character of said first representation with at least one element of a corresponding character of said second representation to form an improved representation.
Claim 2
Dependent Claim
25 words
The improved method of claim 1 further comprising the step of improving said second representation using said improved representation to form a further improved representation.
Claim 3
Dependent Claim
51 words
The improved method of claim 2 further comprising the step of defining a relatively clear representation and a relatively distorted representation from said improved representation and said further improved representation, wherein said relatively clear representation comprises at least one undistorted element corresponding to a distorted element in said relatively distorted representation.
Claim 4
Dependent Claim
113 words
In a method for decoding bar code symbols in which a bar code reader and associated components scan a bar code symbol having a succession of linear elements of different light reflectivity, produce a representation of the symbol and attempt to decode the representation of the symbol in order to produce a legitimate character message containing legitimate characters which are decodable, all non-decodable characters being illegitimate, the improvement comprising the steps of: comparing a plurality of representations obtained from different scanning paths entirely through the same bar code symbol; and modifying at least one illegitimate character in one representation based on at least one legitimate character in a corresponding position in another representation.
Claim 5
Dependent Claim
36 words
The improved method of claim 4 wherein said step of modifying comprises replacing at least one element of an illegitimate character with at least one element of a legitimate character to result in an improved representation.
Claim 6
Independent Claim
103 words
A method of decoding a bar code symbol that may contain distortion, said symbol including a sequence of characters, each character including a plurality of individual elements of different light reflectivity, with a set of predetermined patterns of elements representing legitimate characters, while all other patterns represent illegitimate characters, comprising the steps of: storing a first representation of said bar code symbol derived from scanning entirely through said bar code symbol; storing a second representation of said bar code symbol derived from scanning entirely through said bar code symbol; and improving said first representation using said second representation to form an improved representation.
Claim 7
Dependent Claim
48 words
The method of claim 6 wherein said step of improving said first representation comprises the step of: replacing at least one element of a distorted character of said first representation with at least one element of a corresponding character of said second representation to form said improved representation.
Claim 8
Independent Claim
172 words
A method for decoding indicia in the presence of distortion or image irregularities in portions of the indicia, particularly where such irregularities or distortion are statistically independent, such indicia composed of an ordered sequence of characters, each character including a plurality of individual elements of different light reflectivity with a set of predetermined patterns of elements representing valid characters, while all other patterns represent invalid characters, comprising the steps of: (a) scanning said indicia along a first scanning path and storing a representation of said characters from the scan to form a test sequence; (b) scanning said indicia along another scanning path different from the preceding scanning path and storing a representation of the subsequent sequence of characters from such scan; (c) processing said test sequence and said subsequent sequence by replacing invalid characters in said test sequence with valid characters in the same position in said subsequent sequence to form a new test sequence; and (d) repeating steps (b) through (d) until all characters in said test sequence are valid characters.
Claim 9
Dependent Claim
25 words
The method of claim 8 wherein said elements extend in parallel on a surface so as to form a linear pattern of bars and spaces.
Claim 10
Dependent Claim
146 words
An error-correcting apparatus for decoding a bar code symbol composed of a sequence of characters each having a plurality of elements of different light reflectivity, with a set of predetermined patterns of elements representing valid characters while all other patterns represent invalid characters, comprising: first storage means for storing a first representation of characters of a bar code symbol obtained from scanning a first path through the entire of said bar code symbol; second storage means for storing a second representation of characters of said bar code symbol obtained from scanning a second path through the entire of said bar code symbol; and processing means for iteratively replacing at least one element of an illegitimate character of one of said first and second representations of characters with at least one element of a corresponding character of the other of said first and second representations of characters.
Claim 11
Dependent Claim
26 words
The error-correcting apparatus of claim 10 wherein said elements extend in parallel on a surface so as to form a linear pattern of bars and spaces.
Claim 12
Dependent Claim
103 words
In a method for decoding bar code symbols in which a bar code reader and associated components scan a bar code symbol having a succession of linear elements of different light reflectivity, produce a representation of the symbol and attempt to decode the representation of the symbol in order to produce a legitimate character message containing legitimate characters which are decodable, all non-decodable characters being illegitimate, the improvement comprising the step of: replacing at least one element of an illegitimate character of a first representation with at least one element of a corresponding character of a second representation to form an improved representation.
References Cited (Backward Citations)
No citation records indexed.
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