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US5111310A
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Method and apparatus for halftone rendering of a gray scale image using a blue noise mask
Assignee: RESEARCH Corp TECHNOLOGIES Inc A NOT-FOR-PROFIT NON-STOCK CORPORATION OF
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Filing: 1990-12-04
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Granted: 1992-05-05
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Expires: 2010-12-04
Abstract
Abstract A method of and system for rendering a halftone image of a gray scale image by utilizing a pixel-by-pixel comparison of the gray scale image against a blue noise mask is disclosed in which the gray scale image is scanned on a pixel-by-pixel basis and compared on a pixel-by-pixel basis to an array of corresponding data points contained in a blue noise mask stored in a PROM or computer memory in order to produce the desired halftoned image. Both digital and optically implemented halftone methods are disclosed.
Inventors
- 👤 Kevin J. Parker
- 👤 Theophano Mitsa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:58
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/4084; H; H04; H04N; H04N1/00; H04N1/40; H04N1/40075; H04N1/405; H04N1/4051; H04N1/41; H04N1/4105
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
58 words
A method for the halftoning of gray scale images by utilizing a pixel-by-pixel comparison of the image against a blue noise mask in which the blue noise mask is comprised of a random non-deterministic, non-white noise single valued function which is designed to produce visually pleasing dot profiles when thresholded at any level of said gray scale images.
Claim 2
Independent Claim
58 words
A method for the halftoning of gray scale images by utilizing a pixel-by-pixel comparison of the image against a blue noise mask in which the blue noise mask is comprised of a random non-deterministic, non-white noise single valued function which is designed to produce visually pleasing dot profiles when thresholded at any level of said gray scale images.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said blue noise mask is used to halftone a color image.
Claim 4
Dependent Claim
16 words
The method of claim 1, wherein said blue noise mask is used to halftone multibit displays.
Claim 5
Dependent Claim
21 words
The method of claim 1, wherein said blue noise mask is comprised of a continuous, single valued aperiodic blue noise function.
Claim 6
Dependent Claim
37 words
The method of claim 4, wherein said blue noise function is a random function and in which, when said blue noise mask is thresholded at any level, a dot profile with desirable blue noise characteristics is produced.
Claim 7
Dependent Claim
34 words
The method of claim 1, wherein said blue noise mask is formed by an at least one dimensional function having predetermined properties of a thresholded dot profile using transform domain filtering and error criteria.
Claim 8
Dependent Claim
35 words
The method of claim 6, wherein said blue noise mask is formed by an at least one dimensional function using spatial domain filtering and error criteria equivalent to said transform domain filtering and error criteria.
Claim 9
Independent Claim
94 words
A method for constructing a blue noise mask using a blue noise power spectrum for use for the halftoning of gray scale images by utilizing a pixel-by-pixel comparison of said images against said blue noise mask in which said blue noise mask is constructed by incrementally building up dot profiles over increments in gray level and in which said dot profile at each level is constrained by the dot profile at the previous level and by requiring the matching of each dot profile to said blue noise power spectrum predetermined for that gray level.
Claim 10
Independent Claim
94 words
A method for constructing a blue noise mask using a blue noise power spectrum for use for the halftoning of gray scale images by utilizing a pixel-by-pixel comparison of said images against said blue noise mask in which said blue noise mask is constructed by incrementally building up dot profiles over increments in gray level and in which said dot profile at each level is constrained by the dot profile at the previous level and by requiring the matching of each dot profile to said blue noise power spectrum predetermined for that gray level.
Claim 11
Dependent Claim
23 words
The method of claim 8, wherein said blue noise power spectrum is modified by human visual response to produce an appropriately pleasing pattern.
Claim 12
Independent Claim
36 words
A method for the halftoning of gray scale images by utilizing an optical blue noise mask in which said gray scale image is photographed through said blue noise mask and is printed onto high contrast film.
Claim 13
Independent Claim
36 words
A method for the halftoning of gray scale images by utilizing an optical blue noise mask in which said gray scale image is photographed through said blue noise mask and is printed onto high contrast film.
Claim 14
Dependent Claim
31 words
The method of claim 10, wherein said optical blue noise mask and said image are separately photographed onto said high contrast film such that a repeated exposure of said film occurs.
Claim 15
Dependent Claim
25 words
The method of claim 10, wherein said blue noise mask is formed using a film printer interfaced to a computer containing blue noise mask data.
Claim 16
Independent Claim
104 words
A method of halftoning a gray scale image by utilizing a pixel-by-pixel comparison of said image against a blue noise mask array stored in a first memory, comprising the steps of: a) scanning said gray scale image to be halftoned to create a gray scale image array on a pixel-by-pixel basis; b) storing said gray scale image array in a second memory; c) comparing, on a pixel-by-pixel basis, the value of each corresponding pixel in said blue noise mask array and said gray scale image array to produce a binary image array; and d) converting said binary image array to the desired halftoned image.
Claim 17
Independent Claim
104 words
A method of halftoning a gray scale image by utilizing a pixel-by-pixel comparison of said image against a blue noise mask array stored in a first memory, comprising the steps of: a) scanning said gray scale image to be halftoned to create a gray scale image array on a pixel-by-pixel basis; b) storing said gray scale image array in a second memory; c) comparing, on a pixel-by-pixel basis, the value of each corresponding pixel in said blue noise mask array and said gray scale image array to produce a binary image array; and d) converting said binary image array to the desired halftoned image.
Claim 18
Dependent Claim
27 words
The method of claim 13, wherein said gray scale image array created by said scanning step is fed directly to a computer for performing said comparing step.
Claim 19
Dependent Claim
12 words
The method of claim 13, wherein said image is a color image.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-05 | 1995-11-04 | 1996-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-05 | 1999-11-04 | 2000-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-05 | 2003-11-04 | 2004-05-05 | $7700.00 | Window Closed / Lapsed |