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 Title: |
US5537226:
Method for restoring images scanned in the presence of vibration
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Wolberg, George; Forest Hills, NY
Loce, Robert P.; Webster, NY
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| Assignee: |
Xerox Corporation, Stamford, CT
other patents from XEROX CORPORATION (635240) (approx. 15,002)
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| Published / Filed: |
1996-07-16
/ 1994-11-22
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| Application Number: |
US1994000343390
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| IPC Code: |
Advanced:
H04N 1/047;
H04N 1/19;
H04N 1/40;
H04N 1/10;
H04N 1/193;
Core:
H04N 1/191;
more...
IPC-7:
H04N 1/047;
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| ECLA Code: |
H04N1/047B;
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| U.S. Class: |
Current:
358/486;
358/412;
Original:
358/486;
358/412;
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| Field of Search: |
358/406,412,486,494,404,444
H04N 1047
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| Government Interest: |
This invention was made with U.S. Government support under Grant No. IRI 9157260 awarded by the National Science Foundation. The Government has certain rights in this invention
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| Priority Number: |
| 1994-11-22 |
US1994000343390 |
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| Abstract: |
The present invention is a method and apparatus for restoring or correcting digital images scanned in the presence of mechanical vibration, thereby improving the quality of the output image. In a document scanner, a linear sensor moving relative to a document placed upon a platen is scanned in a manner wherein fluctuations in the nominal scanning velocity are observed. Recognizing that the output of a single photosensor in the linear sensor array is proportional to the integrated irradiance received by the sensor as it scans through an exposure region, when vibratory motion of the sensor array is considered, the actual size of the exposure region is time-varying. The fluctuations or vibrations introduce artifacts such as brightness fluctuation and geometric warping which are eliminated or significantly reduced in accordance with the method of the present invention. Specifically, the instantaneous velocity of the linear sensor array is used to reconstruct an underlying piecewise linear model of the irradiance distribution. That reconstructed image is then resampled under ideal scanning conditions to produce the restored output.
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| Attorney, Agent or Firm: |
Basch, Duane C. ;
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| Primary / Asst. Examiners: |
Vu, Kim Yen;
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| INPADOC Legal Status: |
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Family Legal Status Report
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| Family: |
Show 3 known family members
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First Claim:
Show all 14 claims |
We claim:
1. A method performed in an image processor for processing data defining an image scanned in the presence of mechanical vibration to produce a restored output image, the steps comprising:
- storing image irradiance data in a first memory, where each item of irradiance data stored therein represents a sample of an area of an original document;
- storing, in a second memory, velocity data associated with the image irradiance data, wherein the velocity data reflects a relative instantaneous velocity of a scanning element traveling at a nonuniform velocity measured with respect to the original document;
- modeling, using the image irradiance data and velocity data, an approximation function to represent image irradiance at any point in time;
- identifying control points as a function of a nominal scanning velocity and a fixed sampling time period; and
- resampling the approximation function, using the control points, to determine a restored irradiance level for each area of the original document.
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| Background / Summary: |
Show background / summary
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 7 U.S. patent(s) that reference this one
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| Foreign References: |
None
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| Other Abstract Info: |
DERABS G96-341722
DERG96-341722
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| Other References: |
S. C. Som, "Analysis of the effect of linear smear on photographic images," Journal of the Optical Society of America, 61, 859-864 (Jul. 1971).
D. Wulich and N. S. Kopeika, "Image resolution limits resulting from mechanical vibrations," Optical Engineering 26(6), 529-533 (Jun. 1987).
(5 pages)
Cited by 2 patents
O. Hader, I. Dror, and N. S. Kopeika, "Image resolution limits resulting from mechanical vibrations. Part IV: real-time numerical calculation of optical tranfer functions and experimental verification," Optical Engineering 33(2), 566-577 (Feb. 1994).
(13 pages)
Cited by 3 patents
[ISI abstract]
"Redundant Rastering for Decreased Vibration Sensitivity in Digital Printers," xerox Disclosure Journal, vol. 15, No. 1, (Jan./Feb. 1990), p. 31.
"Modular Driver For Image Scanners," Xerox Disclosure Journal, vol. 18, No. 1, (Jan./Feb. 1993), pp. 7-9.
R. Loce and W. Lama in "Exposure Strobing in Photocopiers," Journal of Imaging Science, 32(6), 238-247 (Nov./Dec. 1988).
(10 pages)
F. Bestenreiner, U. Geis, J. Helmberger, and K. Stadler, "Visibility and Correction of Periodic Interference Structures in Line-by-Line Recorded Images," Journal of Applied Photographic Engineering, 2, 86-92 (1976).
K. Takiguchi, T. Miyagi, A. Okamura, H. Ishoshi and F. Shibata, "Effect of Photoreceptor Drum Rotational Speed Variation on Laser Beam Printer Halftone Reproduction," Proceedings of the SPSE Third International Congress: Recent Advances in Non-Impact Printing Technologies, 168-172, San Francisco (Aug. 1986).
D. Haas, "Contrast Modulation in Halftone Images Produced by Variation in Scan Line Spacing," Journal of Imaging Technology, 15 46(1989).
(10 pages)
Cited by 2 patents
P. Schubert, "Periodic Images Artifacts from Continuous-Tone Laser Scanners," Applied Optics 25(21) 3880-3884 (1986).
(5 pages)
Cited by 3 patents
R. Firth, D. Kessler, E. Muka, M. Noar, and J. Owens, "A Continuous Tone Laser Color Printer," Journal of Imaging Technology 14, 78(1988).
(12 pages)
Cited by 9 patents
P. Burns, M. Rabbani, and L. Ray, "Analysis of Image Noise due to Position Errors in Laser Writers," Applied Optics 25,2158-2168 (1986).
(11 pages)
Cited by 2 patents
P. Melnychuck and R. Shaw, "Fourier Spectra of Digital Halftone Images Containing Dot Position Errors," Journal of the Optical Society of America 5(8), 1328-1338 (1988).
(11 pages)
Cited by 6 patents
S. Bloomberg and P. Engeldrum, "Color Error due to Pixel Placement Errors in a Dot Matrix Printer," Proceedings of the SPSE Third International Congress: Recent Advances in Non-Impact Printing Technologies, 257-260 (Aug. 1986).
R. Loce and W. Lama, "Halftone Banding due to Vibrations in a Xerographic Image Bar Printer," Journal of Imaging Technology, 16(1), 6-11 (1990).
(6 pages)
Cited by 3 patents
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