EP0142767A2
Expired / Lapsed
EP
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Manipulation of graphics image data
Assignee: International Business Machines Corp
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Filing: 1984-11-06
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Granted: —
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Expires: 2004-11-06
Abstract
Abstract Data compression, resolution and coding efficiency of graphic text or line image data is achieved by eliminating transitions between gray levels at edges in an image, converting all gray levels to a common value to achieve a 3 level representation of the image, and reversibly converting the 3 level representation to a bilevel double resolution representation by increasing the data sampling rate and therefore allowing the use of two level data compression techniques. A high resoluton display or printed output may be obtained from the bilevel multiresolution representation.
Inventors
- 👤 Joan La Verne Mitchell
- 👤 William Boone Pennebaker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 08:02
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/403; H; H04; H04N; H04N1/00; H04N1/40; H04N1/40068; H04N1/41
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
59 words
A method for image compression and resolution improvement characterised by: changing an intensity value of any pixel having an intermediate intensity value within a first predetermined range of intermediate intensity values to a predetermined extreme intensity value if said pixel is adjacent to a pixel having a second intermediate intensity value within a second predetermined range of intensity values.
Claim 2
Independent Claim
59 words
A method for image compression and resolution improvement characterised by: changing an intensity value of any pixel having an intermediate intensity value within a first predetermined range of intermediate intensity values to a predetermined extreme intensity value if said pixel is adjacent to a pixel having a second intermediate intensity value within a second predetermined range of intensity values.
Claim 3
Dependent Claim
72 words
A method according to claim 1, further comprising the steps of: converting each representation of said predetermined intermediate intensity value to a plurality of representations of extreme intensity values in accordance with an intensity value of a preceding pixel; converting an original representation of each pixel having an extreme intensity value to a plurality of representations, each of said plurality of representations having an extreme intensity value corresponding to the original representation.
Claim 4
Dependent Claim
27 words
A method according to claim 1, detecting all gray-white pixels adjacent to gray-black pixels; changing each gray-white representation at such detected gray-white pixel to a white representation.
Claim 5
Dependent Claim
54 words
A method according to claim 1, further comprising the steps of: multiplying the number of data samples taken in each clock cycle by a constant; generating for each data sample, an extreme intensity value determined by intensity values of a preceding pixel in said image to improve continuity of runs and thus encoding efficiency.
Claim 6
Dependent Claim
74 words
Apparatus for improving image resolution and compressing image data, comprising: means for storing a digital representation of an image; and means for changing an intensity value of any pixel in said image having an intermediate intensity value within a first predetermined range of intermediate intensity values to a predetermined extreme intensity value if said pixel is adjacent to a pixel having a second intermediate intensity value within a second predetermined range of intensity values.
Claim 7
Dependent Claim
74 words
Apparatus for improving image resolution and compressing image data, comprising: means for storing a digital representation of an image; and means for changing an intensity value of any pixel in said image having an intermediate intensity value within a first predetermined range of intermediate intensity values to a predetermined extreme intensity value if said pixel is adjacent to a pixel having a second intermediate intensity value within a second predetermined range of intensity values.
References Cited (Backward Citations)
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