EP0130415A2
Expired / Lapsed
EP
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Data compression for graphics images
Assignee: International Business Machines Corp
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Filing: 1984-06-08
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Granted: —
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Expires: 2004-06-08
Abstract
Abstract A first bit plane (bit array) is generated of the graphic image, and then, by comparison/logic circuitry, a second bit plane is generated which identifies only pixels of the graphics image representing edges e.g. of characters or lines in the image. The data stream representing the image from the first bit plane is supplemented by edge bits from the second bit plane.
Inventors
- 👤 Dimitris Anastassiou
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:14
CPC Classifications
G; G06; G06T; G06T9/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
62 words
A method for compressing data in a graphics image having at least first and second bit planes, comprising the steps of: identifying edge pixels from an encoding of said first bit plane of said image; and generating at least a single bit for each said edge pixel, indicating whether said edge pixel has an extreme intensity value or an intermediate intensity value.
Claim 2
Independent Claim
62 words
A method for compressing data in a graphics image having at least first and second bit planes, comprising the steps of: identifying edge pixels from an encoding of said first bit plane of said image; and generating at least a single bit for each said edge pixel, indicating whether said edge pixel has an extreme intensity value or an intermediate intensity value.
Claim 3
Dependent Claim
37 words
A method according to claim 1, wherein said identifying further comprises the step of: detecting, for adjacent pixels, a transition in the value of a most significant bit of said pixels indicating an edge in said image.
Claim 4
Dependent Claim
40 words
A method according to claim 1, wherein said identifying and said generating are accomplished by the step of performing a logical exclusive OR on a most significant bit of an intensity value of a current pixel and a previous pixel.
Claim 5
Dependent Claim
62 words
Apparatus for compressing data in a graphics image having at least first and second bit planes, comprising: means for identifying edge pixels from an encoding of said first bit plane of said image; and means for generating at least a single bit for each said edge pixel, indicating whether said edge pixel has a maximum intensity value or an intermediate intensity value.
Claim 6
Dependent Claim
62 words
Apparatus for compressing data in a graphics image having at least first and second bit planes, comprising: means for identifying edge pixels from an encoding of said first bit plane of said image; and means for generating at least a single bit for each said edge pixel, indicating whether said edge pixel has a maximum intensity value or an intermediate intensity value.
Claim 7
Dependent Claim
35 words
Apparatus according to claim 4, wherein said means for identifying further comprises: means for detecting, for adjacent pixels, a transition in a most significant bit value of said pixels indicating an edge in said image.
Claim 8
Dependent Claim
43 words
Apparatus according to claim 4, wherein said means for identifying and said means for generating are combined in a means for performing a logical exclusive OR on a most significant bit of an intensity value of a current pixel and a previous pixel.
References Cited (Backward Citations)
No citation records indexed.
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