Patent US5315406A successfully refreshed from Google Patents.
US5315406A
Expired / Lapsed
US
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Screen generation for halftone screening of images using arbitrary distribution of transformed screen coordinates
Assignee: Individual
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Filing: 1991-12-10
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Granted: 1994-05-24
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Expires: 2011-12-10
Abstract
Abstract A halftone screen with precisely controlled angles and rulings, including irrational screen angles and rulings, for screening photographic images is generated by representing a desired screen pattern in an irregular or non-grid like array of screen elements. In one embodiment, a random array of screen elements is used. In another embodiment, a Poisson-disk distribution of screen elements is used to improve quality. The error between an ideal screen point and an actual screen point in the transformed UV space is calculated and used as the basis for selecting an actual screen point as having the least error between the ideal and actual screen points in UV space. The number of error calculations may be reduced by storing pointers the nearest points to each screen point in transformed UV space, and by storing a plurality of successive screen values at a given angle and screen ruling corresponding to each point in the transformed UV space.
Inventors
- 👤 Raphael L. Levien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:40
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4058
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
149 words
In a method for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said step of computing an error function comprises computing an error vector between an actual screen point and said ideal screen point; and selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 2
Dependent Claim
149 words
In a method for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said step of computing an error function comprises computing an error vector between an actual screen point and said ideal screen point; and selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 3
Independent Claim
137 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as an array of elements representing a desired spot function; transforming a point from said original image to an ideal computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said step of computing an error function comprises computing an error vector between an actual screen point and said ideal screen point; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image.
Claim 4
Independent Claim
137 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as an array of elements representing a desired spot function; transforming a point from said original image to an ideal computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said step of computing an error function comprises computing an error vector between an actual screen point and said ideal screen point; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image.
Claim 5
Dependent Claim
142 words
A method in accordance with claim 2, wherein said step of storing a screen pattern in an array of elements representing a desired spot function, further includes the step of storing a plurality of pointers associated with each said actual screen point and indicating a respective plurality of other actual screen points in said stored screen pattern array; and wherein said step of selecting an actual screen point in said stored screen pattern array of elements which results in the least said computed error function, comprises calculating a plurality of error functions corresponding to the error between each of said plurality of other actual screen points and said ideal screen point to form a respective plurality of error functions; and selecting one of said plurality of other screen points which corresponds to the minimum one of said plurality of calculated error functions.
Claim 6
Dependent Claim
34 words
A method in accordance with claim 2, further including: storing a plurality of screen values for each actual screen point, said plurality of screen values representing successive points of an ideal angled screen pattern.
Claim 7
Dependent Claim
58 words
A method in accordance with claim 2, where said step of screening said original image with said generated screen pattern to form said halftone screened image comprises: comparing said generated screen pattern with said original image; and generating a marking signal for a marking device based on said comparison between said generated screen pattern and said original image.
Claim 8
Independent Claim
157 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as an array of elements representing a desired spot function; transforming a point from said original image to an ideal screen point; computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image, wherein said step of computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array comprises calculating an error vector between said actual screen point and said ideal screen point.
Claim 9
Independent Claim
157 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as an array of elements representing a desired spot function; transforming a point from said original image to an ideal screen point; computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image, wherein said step of computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array comprises calculating an error vector between said actual screen point and said ideal screen point.
Claim 10
Dependent Claim
50 words
A method in accordance with claim 6, wherein said step of calculating an error vector based on the error between said ideal screen point and said actual screen point comprises: calculating an error vector in transformed UV space between said actual screen sample point and said ideal screen sample point.
Claim 11
Dependent Claim
38 words
A method in accordance with claim 6, wherein said error vector calculation is approximated as the sum of the absolute values of the orthogonal components of the displacement between said actual screen point and said ideal screen point.
Claim 12
Dependent Claim
100 words
In a method for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: storing said screen pattern as a non-grid array of elements representing said desired spot function.
Claim 13
Dependent Claim
100 words
In a method for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: storing said screen pattern as a non-grid array of elements representing said desired spot function.
Claim 14
Independent Claim
87 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as a non-grid array of elements representing a desired spot function; transforming a point from said original image to an ideal screen point; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image.
Claim 15
Independent Claim
87 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as a non-grid array of elements representing a desired spot function; transforming a point from said original image to an ideal screen point; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image.
Claim 16
Dependent Claim
18 words
A method in accordance with claim 10, wherein said non-grid array is a random distribution of screen points.
Claim 17
Dependent Claim
18 words
A method in accordance with claim 10, wherein said non-grid array is a pseudo-random distribution of screen points.
Claim 18
Dependent Claim
18 words
A method in accordance with claim 10, wherein said non-grid array is a Poisson-disk distribution of screen points.
Claim 19
Dependent Claim
58 words
A method in accordance with claim 10, where said step of screening said original image with said generated screen pattern to form said halftone screened image comprises: comparing said generated screen pattern with said original image; and generating a marking signal for a marking device based on said comparison between said generated screen pattern and said original image.
Claim 20
Dependent Claim
141 words
In a method for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: storing said screen pattern as an non-grid array of elements representing said desired spot function; computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; and selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 21
Dependent Claim
141 words
In a method for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: storing said screen pattern as an non-grid array of elements representing said desired spot function; computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; and selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 22
Independent Claim
117 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as a non-grid array of elements representing a desired spot function; transforming a point from said original image to an ideal screen point; computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image.
Claim 23
Independent Claim
117 words
A method for generating a halftone screened image from an original image at a desired screen angle, said method comprising: storing a screen pattern as a non-grid array of elements representing a desired spot function; transforming a point from said original image to an ideal screen point; computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and screening said original image with said generated screen pattern to form said halftone screened image.
Claim 24
Dependent Claim
48 words
A method in accordance with claim 16, wherein said step of computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array comprises. calculating an error vector between said actual screen point and said ideal screen point.
Claim 25
Dependent Claim
50 words
A method in accordance with claim 17, wherein said step of calculating an error vector based on the error between said ideal screen point and said actual screen point comprises: calculating an error vector in transformed UV space between said actual screen sample point and said ideal screen sample point.
Claim 26
Dependent Claim
38 words
A method in accordance with claim 17, wherein said error vector calculation is approximated as the sum of the absolute values of the orthogonal components of the displacement between said actual screen point and said ideal screen point.
Claim 27
Dependent Claim
143 words
A method in accordance with claim 16, wherein said step of storing a screen pattern in an array of elements representing a desired spot function, further includes the step of storing a plurality of pointers associated with each said actual screen point and indicating a respective plurality of other actual screen points in said stored screen pattern array; and wherein said step of selecting an actual screen point in said stored screen pattern array of elements which results in the least said computed error function, comprises calculating a plurality of error functions corresponding to the error between each of said plurality of other actual screen points and said ideal screen point to form a respective plurality of error functions; and selecting one of said plurality of other actual screen points which corresponds to the minimum one of said plurality of calculated error functions.
Claim 28
Dependent Claim
34 words
A method in accordance with claim 16, further including: storing a plurality of screen values for each actual screen point, said plurality of screen values representing successive points of an ideal angled screen pattern.
Claim 29
Dependent Claim
58 words
A method in accordance with claim 16, where said step of screening said original image with said generated screen pattern to form said halftone screened image comprises: comparing said generated screen pattern with said original image; and generating a marking signal for a marking device based on said comparison between said generated screen pattern and said original image.
Claim 30
Dependent Claim
151 words
In an apparatus for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transform a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said means for computing an error function comprises means for computing an error vector between an actual screen point and said ideal screen point; and means for selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 31
Dependent Claim
151 words
In an apparatus for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transform a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said means for computing an error function comprises means for computing an error vector between an actual screen point and said ideal screen point; and means for selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 32
Independent Claim
151 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as an array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said means for computing an error function comprises means for computing an error vector between an actual screen point and said ideal screen point; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image.
Claim 33
Independent Claim
151 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as an array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array, wherein said means for computing an error function comprises means for computing an error vector between an actual screen point and said ideal screen point; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image.
Claim 34
Dependent Claim
145 words
An apparatus in accordance with claim 24, wherein said means for storing a screen pattern in an array of elements representing a desired spot function, further includes the means for storing a plurality of pointers associated with each said actual screen point and indicating a respective plurality of other actual screen points in said stored screen pattern array; and wherein said means for selecting an actual screen point in said stored screen pattern array of elements which results in the least said computed error function, comprises calculating a plurality of error functions corresponding to the error between each of said plurality of other actual screen points and said ideal screen point to form a respective plurality of error functions; and means for selecting one of said plurality of other actual screen points which corresponds to the minimum one of said plurality of calculated error functions.
Claim 35
Dependent Claim
36 words
An apparatus in accordance with claim 24, further including: means for storing a plurality of screen values for each actual screen point, said plurality of screen values representing successive points of an ideal angled screen pattern.
Claim 36
Dependent Claim
62 words
An apparatus in accordance with claim 24, where said means for screening said original image with said generated screen pattern to form said halftone screened image comprises: means for comparing said generated screen pattern with said original image; and means for generating a marking signal for a marking device based on said comparison between said generated screen pattern and said original image.
Claim 37
Independent Claim
169 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as an array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image, wherein said means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array comprises means for calculating an error vector between said actual screen point and said ideal screen point.
Claim 38
Independent Claim
169 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as an array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image, wherein said means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array comprises means for calculating an error vector between said actual screen point and said ideal screen point.
Claim 39
Dependent Claim
52 words
An apparatus in accordance with claim 28, wherein said means for calculating an error vector based on the error between said ideal screen point and said actual screen point comprises: means for calculating an error vector in transformed UV space between said actual screen sample point and said ideal screen sample point.
Claim 40
Dependent Claim
38 words
An apparatus in accordance with claim 28, wherein said error vector calculation is approximated as the sum of the absolute values of the orthogonal components of the displacement between said actual screen point and said ideal screen point.
Claim 41
Dependent Claim
102 words
In an apparatus for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: means for storing said screen pattern as a non-grid array of elements representing said desired spot function.
Claim 42
Dependent Claim
102 words
In an apparatus for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: means for storing said screen pattern as a non-grid array of elements representing said desired spot function.
Claim 43
Independent Claim
95 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as a non-grid array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image.
Claim 44
Independent Claim
95 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as a non-grid array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image.
Claim 45
Dependent Claim
18 words
An apparatus in accordance with claim 32, wherein said non-grid array is a random distribution of screen points.
Claim 46
Dependent Claim
18 words
An apparatus in accordance with claim 32, wherein said non-grid array is a pseudo-random distribution of screen points.
Claim 47
Dependent Claim
18 words
An apparatus in accordance with claim 32, wherein said non-grid array is a Poisson-disk distribution of screen points.
Claim 48
Dependent Claim
62 words
An apparatus in accordance with claim 32, where said means for screening said original image with said generated screen pattern to form said halftone screened image comprises: means for comparing said generated screen pattern with said original image; and means for generating a marking signal for a marking device based on said comparison between said generated screen pattern and said original image.
Claim 49
Dependent Claim
147 words
In an apparatus for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: means for storing said screen pattern as an non-grid array of elements representing said desired spot function; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; and means for selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 50
Dependent Claim
147 words
In an apparatus for generating a halftone screened image from an original image at a desired screen angle, said method including storing a screen pattern as an array of elements representing a desired spot function, transforming a point from said original image to an ideal screen point, selecting an actual screen point in said stored screen pattern array of elements to form a generated screen pattern, and screening said original image with said generated screen pattern to form said halftone screened image, the improvement comprising: means for storing said screen pattern as an non-grid array of elements representing said desired spot function; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; and means for selecting said actual screen point in said stored screen pattern which produces the least said computed error function.
Claim 51
Independent Claim
127 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as a non-grid array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image.
Claim 52
Independent Claim
127 words
An apparatus for generating a halftone screened image from an original image at a desired screen angle, said method comprising: means for storing a screen pattern as a non-grid array of elements representing a desired spot function; means for transforming a point from said original image to an ideal screen point; means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array; means for selecting an actual screen point in said stored screen pattern array of elements responsive to said transformed point, which produces the least said computed error function, to form a generated screen pattern; and means for screening said original image with said generated screen pattern to form said halftone screened image.
Claim 53
Dependent Claim
50 words
An apparatus in accordance with claim 38, wherein said means for computing an error function based on the error between said ideal screen point and actual points in said stored screen pattern array comprises: means for calculating an error vector between said actual screen point and said ideal screen point.
Claim 54
Dependent Claim
52 words
An apparatus in accordance with claim 39, wherein said means for calculating an error vector based on the error between said ideal screen point and said actual screen point comprises: means for calculating an error vector in transformed UV space between said actual screen sample point and said ideal screen sample point.
Claim 55
Dependent Claim
38 words
An apparatus in accordance with claim 39, wherein said error vector calculation is approximated as the sum of the absolute values of the orthogonal components of the displacement between said actual screen point and said ideal screen point.
Claim 56
Dependent Claim
145 words
An apparatus in accordance with claim 38, wherein said means for storing a screen pattern in an array of elements representing a desired spot function, further includes the means for storing a plurality of pointers associated with each said actual screen point and indicating a respective plurality of other actual screen points in said stored screen pattern array; and wherein said means for selecting an actual screen point in said stored screen pattern array of elements which results in the least said computed error function, comprises calculating a plurality of error functions corresponding to the error between each of said plurality of other actual screen points and said ideal screen point to form a respective plurality of error functions; and means for selecting one of said plurality of other actual screen points which corresponds to the minimum one of said plurality of calculated error functions.
Claim 57
Dependent Claim
36 words
An apparatus in accordance with claim 38, further including: means for storing a plurality of screen values for each actual screen point, said plurality of screen values representing successive points of an ideal angled screen pattern.
Claim 58
Dependent Claim
62 words
An apparatus in accordance with claim 38, where said means for screening said original image with said generated screen pattern to form said halftone screened image comprises: means for comparing said generated screen pattern with said original image; and means for generating a marking signal for a marking device based on said comparison between said generated screen pattern and said original image.
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| 11.5 Years (Year 12) | 2005-05-23 | 2005-11-22 | 2006-05-24 | $7700.00 | Window Closed / Lapsed |