US4558370A
Expired / Lapsed
US
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Image processing method for graphics images
Assignee: International Business Machines Corp
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Filing: 1983-11-21
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Granted: 1985-12-10
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Expires: 2003-11-21
Abstract
Abstract Graphics images are generally considered to be those images comprised of text and/or line drawings. Data compression of graphics images is desired whenever a fast image transmission speed is desired in a limited band width channel. It is also used for storage of a large number of images in a limited capacity storage system. The method and apparatus described herein improves data compression, resolution and coding efficiency 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 a graphics 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 resolution display or printed output may be obtained from the bilevel multiresolution representation.
Inventors
- 👤 Joan L. Mitchell
- 👤 William B. Pennebaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:21
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: 23
Claim 1
Independent Claim
111 words
In a method for converting a graphics image into data representing the intensity values of the image pixels in binary format as either of two extreme values, e.g., black and white, as well as intermediate intensity values between said two extreme values, e.g., grays, to achieve efficient compression, resolution, and coding, the improvement comprising the step of: changing the intensity value of each pixel having an intermediate intensity value within a first predetermined range of said intermediate intensity values to a predetermined one of said extreme intensity values if said pixel is adjacent to a pixel having an intermediate intensity value within a second predetermined range of said intermediate intensity values.
Claim 2
Dependent Claim
111 words
In a method for converting a graphics image into data representing the intensity values of the image pixels in binary format as either of two extreme values, e.g., black and white, as well as intermediate intensity values between said two extreme values, e.g., grays, to achieve efficient compression, resolution, and coding, the improvement comprising the step of: changing the intensity value of each pixel having an intermediate intensity value within a first predetermined range of said intermediate intensity values to a predetermined one of said extreme intensity values if said pixel is adjacent to a pixel having an intermediate intensity value within a second predetermined range of said intermediate intensity values.
Claim 3
Dependent Claim
57 words
A method according to claim 1, wherein pixels within said first predetermined range of intermediate intensity values are gray-white and pixels within said second range of intermediate intensity values are gray-black, and further comprising the steps of: detecting all gray-white pixels adjacent to gray-black pixels; and changing the intensity value of each such gray-white pixel to white.
Claim 4
Dependent Claim
41 words
A method according to claim 1, comprising the further step of: changing the intensity values of all pixels having intensity values among a first plurality of intermediate intensity values to a value among a second plurality of fewer intermediate intensity values.
Claim 5
Dependent Claim
30 words
A method according to claim 1, further comprising the step of: changing the intensity value of each pixel having an intermediate intensity value to a common predetermined intermediate intensity value.
Claim 6
Dependent Claim
17 words
A method according to claim 4 wherein said changing step comprises the use of a lookup table.
Claim 7
Dependent Claim
75 words
A method according to claim 1, further comprising the steps of: converting each representation of a pixel having an intermediate intensity value to a plurality of representations of extreme intensity values in accordance with the intensity values of its adjacent pixels; and 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 8
Dependent Claim
17 words
A method according to claim 6 wherein said converting step comprises the use of a lookup table.
Claim 9
Dependent Claim
23 words
A method according to claim 6, comprising the further step of: encoding each of said pixel represntations for storage of said image data.
Claim 10
Dependent Claim
23 words
A method according to claim 6, further comprising the step of: encoding each of said pixel representations for transmission of said image data.
Claim 11
Dependent Claim
37 words
A method according to claim 9, further comprising the steps of: decoding said encoded representations; detecting each pixel having an intermediate intensity value; and changing the value of each such detected pixel to a predetermined intensity value.
Claim 12
Dependent Claim
111 words
Apparatus for improving image resolution and image data compression of a graphics image that has had the intensity values of its pixels converted into data in binary format as either of two extreme values, e.g., black and white, and intermediate intensity values, e.g., grays, comprising: means for storing said image data; and means for changing the intensity value of each pixel in said image having an intermediate intensity value within a first predetermined range of said intermediate intensity values to a predetermined one of said extreme intensity values if said pixel is adjacent to a pixel having an intermediate intensity value within a second predetermined range of said intermediate intensity range.
Claim 13
Dependent Claim
111 words
Apparatus for improving image resolution and image data compression of a graphics image that has had the intensity values of its pixels converted into data in binary format as either of two extreme values, e.g., black and white, and intermediate intensity values, e.g., grays, comprising: means for storing said image data; and means for changing the intensity value of each pixel in said image having an intermediate intensity value within a first predetermined range of said intermediate intensity values to a predetermined one of said extreme intensity values if said pixel is adjacent to a pixel having an intermediate intensity value within a second predetermined range of said intermediate intensity range.
Claim 14
Dependent Claim
28 words
Apparatus according to claim 11, further comprising: means for changing the intensity value of each pixel having an intermediate intensity value to a common predetermined intermediate intensity value.
Claim 15
Dependent Claim
57 words
Apparatus according to claim 11, wherein pixels within said first predetermined range of intermediate intensity values are gray-white and pixels within said second range of intermediate intensity values are gray-black, and further comprising: means for detecting all gray-white pixels adjacent to gray-black pixels; and means for changing the intensity value of each such gray-white pixel to white.
Claim 16
Dependent Claim
75 words
Apparatus according to claim 11, further comprising: means for converting each representation of a pixel having an intermediate intensity value to a plurality of representations of extreme intensity values in accordance with the intensity values of its adjacent pixels; and means for 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 17
Dependent Claim
13 words
Apparatus according to claim 14 wherein said converting means comprises a lookup table.
Claim 18
Dependent Claim
21 words
Apparatus according to claim 11, further comprising: means for encoding each of said pixel representations for transmission of said image data.
Claim 19
Dependent Claim
39 words
Apparatus according to claim 16, further comprising: means for decoding said encoded representations; means for detecting each pixel having an intermediate intensity value; and means for changing the value of each such detected pixel to a predetermined intensity value.
Claim 20
Independent Claim
78 words
A method for graphics image processing to improve compression and resolution comprising the steps of: converting a graphics image into data in binary format representing the intensity values of the image pixels as either of two extreme values, black and white, or of two intermediate intensity values between said two extreme values, gray-black and gray-white; detecting all gray-white pixels adjacent to gray-black pixels in the image; and changing the intensity value of each such gray-white pixel to white.
Claim 21
Independent Claim
78 words
A method for graphics image processing to improve compression and resolution comprising the steps of: converting a graphics image into data in binary format representing the intensity values of the image pixels as either of two extreme values, black and white, or of two intermediate intensity values between said two extreme values, gray-black and gray-white; detecting all gray-white pixels adjacent to gray-black pixels in the image; and changing the intensity value of each such gray-white pixel to white.
Claim 22
Dependent Claim
81 words
A method as in claim 18, comprising the further steps of: changing the intensity values of all pixels having an intermediate intensity value to a common intermediate intensity representation, gray; converting each gray representation to a pair of extreme representations each in conformance with the representation of its adjacent extreme intensity value pixel; converting each extreme value pixel representation to a pair of identical extreme value representations; and encoding all of said pixel representations for the transmissions of said image data.
Claim 23
Dependent Claim
17 words
A method as in claim 19 wherein said converting steps comprise the use of a lookup table.
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USPTO Annuity & Maintenance Windows
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|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |