EP0569962A2
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EP
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Method and apparatus for processing low resolution images of degraded bar code symbols
Assignee: United Parcel Service of America Inc
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Filing: 1993-05-12
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Granted: —
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Expires: 2013-05-12
Abstract
Abstract A system is disclosed for processing a two dimensional digital image representative of a bar code symbol. The bar code symbol is oriented in a bar direction. The system includes means for dividing the two dimensional image into a plurality of two dimensional sections perpendicular to the bar direction. Means (1010) for determining information representative of the intensity of a plurality of such sections is also provided. A one dimensional intensity projection signal is formed from the determined information. The system also includes means (1050) for calculating the areas of a plurality of regions described by the projection signal. The widths of a plurality of bars in the bar code symbol are determined from the calculated areas.
Inventors
- 👤 Stefan Surka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 07:59
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10821; G06K7/1092
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
98 words
A method for processing a two dimensional digital image representative of a bar code symbol oriented in a bar direction, comprising the steps of: (A) dividing said two dimensional image into a plurality of two dimensional sections perpendicular to said bar direction; (B) determining information representative of the intensity of a plurality of said sections; (C) forming a one dimensional intensity projection signal from said information; (D) calculating the areas of a plurality of regions described by said projection signal; and (E) determining the widths of a plurality of bars in said bar code symbol from said areas.
Claim 2
Dependent Claim
47 words
The method of claim 1, wherein step (C) further comprises the steps of: (1) determining from said projection signal a minimum global scaling parameter and a maximum global scaling parameter; and (2) globally scaling said projection signal in accordance with said minimum and maximum global scaling values.
Claim 3
Dependent Claim
71 words
The method of claim 2, wherein step (C)(1) comprises the steps of: (a) determining a plurality of local minimum values from said projection signal; (b) determining said minimum global scaling parameter from an average of said plurality of local minimum values; (c) determining a plurality of local maximum values from said projection signal; and (d) determining said maximum global scaling parameter from an average of said plurality of local maximum values.
Claim 4
Dependent Claim
29 words
The method of claim 3, wherein step (C) further comprises the step of: (3) locally scaling said projection signal in accordance with said local minimum and local maximum values.
Claim 5
Dependent Claim
101 words
The method of claim 4, wherein step (C)(3) comprises the steps of: (a) positioning a sliding window on said projection signal; (b) calculating a contrast value for pixels in said window; (c) comparing said contrast value to a predetermined threshold; (d) if said contrast value exceeds said predetermined threshold then locally scaling pixels in said window otherwise marking pixels in said window as undefined; (e) moving said sliding window a distance equal to one bin to the right; (f) repeating steps (a) - (e) for the full length of said projection signal; and (g) resolving by linear interpolation pixels marked undefined.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein said two dimensional digital image is representative of a corrupted bar code symbol.
Claim 7
Independent Claim
108 words
An apparatus for processing a two dimensional digital image representative of a bar code symbol oriented in a bar direction, comprising: (A) means for dividing said two dimensional image into a plurality of two dimensional sections perpendicular to said bar direction; (B) means for determining information represenative of the intensity of a plurality of said sections; (C) means (1010) for forming a one dimensional intensity projection signal from said information; (D) means (1050) for calculating the areas of a plurality of regions described by said projection signal; and (E) mean (1060) for determining the widths of a plurality of bars in said bar code symbol from said areas.
Claim 8
Dependent Claim
51 words
The apparatus of claim 7, wherein said means for forming further comprises: (1) means for determining from said projection signal a minimum global scaling parameter and a maximum global scaling parameter; and (2) means (1020) for globally scaling said projection signal in accordance with said minimum and maximum global scaling values.
Claim 9
Dependent Claim
78 words
The apparatus of claim 8, wherein said means for selecting comprises: (a) means for determining a plurality of local minimum values from said projection signal; (b) means for determining said minimum global scaling parameter from an average of said plurality of local minimum values; (c) means for determining a plurality of local maximum values from said projection signal; and (d) means for determining said maximum global scaling parameter from an average of said plurality of local maximum values.
Claim 10
Dependent Claim
31 words
The apparatus of claim 9, wherein said means for forming further comprises: (3) means (1030) for locally scaling said projection signal in accordance with said local minimum and local maximum values.
Claim 11
Dependent Claim
94 words
The apparatus of claim 10, wherein said means for locally scaling comprises: (a) means for positioning a sliding window on said projection signal; (b) means for calculating a contrast value for pixels in said window; (c) means for comparing said contrast value to a predetermined threshold; (d) means for locally scaling pixels in said window if said contrast value exceeds said predetermined threshold; (e) means (1040) marking pixels in said window as undefined if said contrast value does not exceed said predetermined threshold; and (f) means for resolving by linear interpolation pixels marked undefined.
Claim 12
Dependent Claim
19 words
The apparatus of claim 7, wherein said two dimensional digital image is representative of a corrupted bar code symbol.
References Cited (Backward Citations)
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