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EP0881822A2
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Luminance-based color resolution enhancement
Assignee: HP Inc
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Filing: 1998-04-30
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Granted: —
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Expires: 2018-04-30
Abstract
Abstract A method and apparatus enhance a color or grayscale raster image in a printer (10) by identifying a working pixel (48,108) in the raster image for anti-aliasing, and then modifying luminance data (52,112) of the working pixel in a luminance chrominance color space such that an anti-aliasing effect is achieved relative to the raster image. The luminance component of the raster image data is converted to a binary format (106) to identify the working pixel using RET template matching (108). The luminance data of the working pixel is modified by utilizing luminance data of adjacent pixels (52,112) to produce a new luminance value which is then assigned to the working pixel. One of the adjacent pixels defines an edge of the object being anti-aliased in the raster image, and the other of the adjacent pixels defines an edge of a region in the raster image that is adjacent the object. In the event chroma data is associated with the object, the chroma data is combined with the modified luminance data (118) and also assigned to the working pixel for accurate imaging thereof.
Inventors
- 👤 Richard Benear
- 👤 James R. Nottingham
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 20:23
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/403; H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4092; H04N1/46; H04N1/56; H04N1/58
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
60 words
A method of enhancing a multi-bit per pixel raster image,
comprising: (a) converting luminance data of the multi-bit per pixel
raster image to binary data per pixel (46,106); (b) identifying a working pixel from the binary data
(48,108,110); and, (c) modifying luminance data of the working pixel
(52,112) such that an anti-aliasing effect is achieved relative to the raster
image.
Claim 2
Dependent Claim
30 words
The method of claim 1 wherein the working pixel is
identified in the raster image by recognizing a configuration of a plurality of pixel
data adjacent the working pixel (48,108,110).
Claim 3
Dependent Claim
58 words
The method of claim 1 or 2 wherein: (a) if the raster image is a color image, then the
luminance data is indicative of a brightness of color associated with the working
pixel, and; (b) if the raster image is a grayscale image, then the
luminance data is indicative of a grayscale value associated with the working
pixel.
Claim 4
Dependent Claim
41 words
The method of claim 1, 2 or 3 wherein modifying luminance
data of the working pixel includes utilizing luminance data of adjacent pixels
(112) to produce a new luminance value and then assigning the new luminance
value to the working pixel.
Claim 5
Dependent Claim
52 words
The method of claim 4 wherein the raster image defines at
least one object therein to be anti-aliased, and wherein one of the adjacent
pixels defines an edge of the object, and another of the adjacent pixels defines
an edge of a region in the raster image that is adjacent the object.
Claim 6
Dependent Claim
55 words
The method of claim 1, 2, 3, 4 or 5 wherein the raster
image defines at least one object therein to be anti-aliased, and further including,
in the event the object has chroma data, combining certain of the chroma data
with the modified luminance data (114) and assigning the combined data to the
working pixel.
Claim 7
Dependent Claim
79 words
The method of claim 6 wherein: (a) if the working pixel defines part of the object prior to
being anti-aliased, then the certain of the chroma data is chrome data of the
working pixel (114,116); and, (b) if the working pixel does not define part of the object
prior to being anti-aliased, then the certain of the chroma data is chrome data of
a pixel that defines part of the object and that is adjacent the working pixel
(114,118).
Claim 8
Dependent Claim
80 words
A resolution enhancement apparatus for enhancing
resolution of a multi-bit per pixel raster image, comprising: (a) conversion apparatus (34,46) for converting
luminance data of the multi-bit per pixel raster image to binary data per pixel; (a) pixel identification apparatus (32,48) for identifying a
working pixel in the binary data for anti-aliasing; and, (b) luminance modification apparatus (32,52) for
modifying luminance data of the working pixel whereby an anti-aliasing effect is
achieved for the working pixel relative to the raster image.
Claim 9
Dependent Claim
42 words
The apparatus of claim 8 wherein the luminance
modification apparatus (32,52) provides for utilizing luminance data of pixels
adjacent to the working pixel to produce a new luminance value and further
provides for assigning the new luminance value to the working pixel.
Claim 10
Dependent Claim
42 words
The apparatus of claim 9 wherein one of the adjacent pixels
defines an edge of an object in the raster image, and another of the adjacent
pixels defines an edge of a region in the raster image that is adjacent the object.
Claim 11
Dependent Claim
53 words
The apparatus of claim 8, 9 or 10 wherein the raster image
defines at least one object therein to be anti-aliased, and further including
chroma modification apparatus (52) for combining certain chroma data of the
object, if any, with the modified luminance data and for assigning the combined
data to the working pixel.
Claim 12
Dependent Claim
83 words
The apparatus of claim 8, 9, 10 or 11 wherein: (a) if the working pixel defines part of the object prior to
being anti-aliased, then the certain chrome data of the object is chroma data of
the working pixel; and, (b) if the working pixel does not define part of the object
prior to being anti-aliased, then the certain chrome data of the object is chroma
data of a pixel that defines part of the object and that is adjacent the working
pixel.
References Cited (Backward Citations)
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