Patent US5225915A successfully refreshed from Google Patents.
US5225915A
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Image processing with noise enhancing operators for moire reduction and/or random dot generation
Assignee: Xerox Corp
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Filing: 1989-06-09
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Granted: 1993-07-06
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Expires: 2009-06-09
Abstract
Abstract In an image processing device for processing image data representing an image, and including an image filtering arrangement, a filter function is applied to the image data that greatly amplifies or enhanced high frequency imge data, including noise inherent in the image. Such noise, which may be the granularity of the image, when enhanced, serves to mask the beating pattern of moire. One function which accomplishes adequate high frequency and noise filtering is a modified Laplacian function with a maximum modulation at a frequency of the noise or granularity of the image. Similarly, the special effect of a random screen image or mezzo tint is obtained when a continuous tone image is processed with the modified Laplacian filtering function, and subsequently thresholded in a thresholding arrangement.
Inventors
- 👤 Theresa J. Ciccone
- 👤 Ranjit Bhaskar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:36
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40075; H04N1/405; H04N1/409
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
98 words
A method of processing digital image data to alter the appearance thereof, including the steps: (a) supplying image data, said image data including inherent random noise, and having an original periodic function, said image data having superimposed thereon an additional periodic function, said original and additional periodic functions having frequencies creating a moire pattern in said image data; (b) applying a filter function to the image data supplied, said filter function having the characteristics of enhancing high frequency and noise of said image data, whereby enhancement of said random noise masks the moire pattern in said image data.
Claim 2
Independent Claim
98 words
A method of processing digital image data to alter the appearance thereof, including the steps: (a) supplying image data, said image data including inherent random noise, and having an original periodic function, said image data having superimposed thereon an additional periodic function, said original and additional periodic functions having frequencies creating a moire pattern in said image data; (b) applying a filter function to the image data supplied, said filter function having the characteristics of enhancing high frequency and noise of said image data, whereby enhancement of said random noise masks the moire pattern in said image data.
Claim 3
Dependent Claim
27 words
The image processing method defined in claim 1 wherein the filter function applied is a modified Laplacian function, having a maxima at a frequency optimizing noise enhancement.
Claim 4
Dependent Claim
103 words
An arrangement for processing digital image data to alter the appearance thereof, including: means for supplying image data, said image data including inherent random noise, and having an original periodic function, said means for supplying image data, superimposing on said image data an additional periodic function, said original and additional periodic functions having frequencies creating a moire pattern in said image data; means for applying a filter function to the image data supplied, said filter function having the characteristics of enhancing high frequency and noise of said image data, whereby, enhancement of said random noise masks the moire pattern in said image data.
Claim 5
Dependent Claim
103 words
An arrangement for processing digital image data to alter the appearance thereof, including: means for supplying image data, said image data including inherent random noise, and having an original periodic function, said means for supplying image data, superimposing on said image data an additional periodic function, said original and additional periodic functions having frequencies creating a moire pattern in said image data; means for applying a filter function to the image data supplied, said filter function having the characteristics of enhancing high frequency and noise of said image data, whereby, enhancement of said random noise masks the moire pattern in said image data.
Claim 6
Dependent Claim
27 words
The image processing arrangement defined in claim 3 wherein the filter function applied is a modified Laplacian function, having a maxima at a frequency optimizing noise enhancement.
Claim 7
Dependent Claim
70 words
An arrangement for processing digital image data to alter the appearance thereof with a simulated random screen effect, including: means for supplying image data, said image data including inherent random noise; means for applying a filter function to the image data supplied, said filter function having the characteristics of enhancing high frequency elements and noise of said image data; and means for applying a threshold level to said image data.
Claim 8
Dependent Claim
70 words
An arrangement for processing digital image data to alter the appearance thereof with a simulated random screen effect, including: means for supplying image data, said image data including inherent random noise; means for applying a filter function to the image data supplied, said filter function having the characteristics of enhancing high frequency elements and noise of said image data; and means for applying a threshold level to said image data.
Claim 9
Dependent Claim
27 words
The image processing arrangement defined in claim 5 wherein the filter function applied is a modified Laplacian function, having a maxima at a frequency optimizing noise enhancement.
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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) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |