Patent US602353A successfully refreshed from Google Patents.
Patent US5307175A successfully refreshed from Google Patents.
US5307175A
Expired / Lapsed
US
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Optical image defocus correction
Assignee: Xerox Corp
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Filing: 1992-03-27
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Granted: 1994-04-26
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Expires: 2012-03-27
Abstract
Abstract In an optical/electrical imaging system, optical depth of focus corrections are accomplished electronically. A plurality of defocus states of the optical system are measured and/or determined and image restoration coefficients corresponding to each of these states are stored. The state of defocus of the imaging system is then determined by deriving an image from a target having known characteristics, which are then correlated to determine a state of defocus. A microprocessor is utilized to provide appropriate defocus correction information to an electronic filter, thereby providing an adaptive filtering arrangement.
Inventors
- 👤 Ned J. Seachman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:08
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/00002; H04N1/00007; H04N1/00013; H04N1/00026; H04N1/00034; H04N1/00045; H04N1/00053; H04N1/00063; H04N1/00071; H04N1/00082; H04N1/40; H04N1/409; H04N1/4092
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
180 words
Image scanning apparatus comprising: an image support; a scanner for scanning an image on the image support, said scanner comprising an optical element for receiving optical image data from an image on the image support and a photoreceptor for receiving optical image data from the optical element and converting the optical data to an electrical data signal; restoring means for providing a plurality of sets of image restoration data, each set of image restoration data representative of a different one of a plurality of defocus states of the optical element throughout an expected range of focal errors; determining means for determining at least one defocus state of the scanner; selecting means for selecting at least one of the sets of image restoration data provided by the restoring means based on the at least one defocus state determined by the determining means; signal processing means for receiving the electrical data signal from the photoreceptor and the image restoration data from the selecting means and modifying the electrical data signal in accordance with the image restoration data received from the selecting means.
Claim 2
Dependent Claim
180 words
Image scanning apparatus comprising: an image support; a scanner for scanning an image on the image support, said scanner comprising an optical element for receiving optical image data from an image on the image support and a photoreceptor for receiving optical image data from the optical element and converting the optical data to an electrical data signal; restoring means for providing a plurality of sets of image restoration data, each set of image restoration data representative of a different one of a plurality of defocus states of the optical element throughout an expected range of focal errors; determining means for determining at least one defocus state of the scanner; selecting means for selecting at least one of the sets of image restoration data provided by the restoring means based on the at least one defocus state determined by the determining means; signal processing means for receiving the electrical data signal from the photoreceptor and the image restoration data from the selecting means and modifying the electrical data signal in accordance with the image restoration data received from the selecting means.
Claim 3
Dependent Claim
18 words
Apparatus as in claim 1, further comprising display means for displaying image data received from the processing means.
Claim 4
Dependent Claim
22 words
Apparatus as in claim 1, wherein the providing means comprises a memory for storing the plurality of sets of image restoration data.
Claim 5
Dependent Claim
19 words
Apparatus as in claim 1, wherein the providing means utilizes a Weiner filter to compute the image restoration data.
Claim 6
Dependent Claim
28 words
Apparatus as in claim 1, further including means for providing image quality data to the processing means indicative of the quality of an image on the image support.
Claim 7
Dependent Claim
18 words
Apparatus as in claim 5, wherein the means for providing image quality data comprises a manually selectable member.
Claim 8
Dependent Claim
43 words
Apparatus as in claim 1, further comprising a focus target and wherein the determining means determines one of a plurality of levels of defocus of the optical system formed by the image support and the scanner from image data from the focus target.
Claim 9
Dependent Claim
12 words
Apparatus as in claim 1, wherein the optical element is a lens.
Claim 10
Dependent Claim
14 words
Apparatus as in claim 1, wherein the optical element is an array of lenses.
Claim 11
Dependent Claim
15 words
Apparatus as in claim 1, wherein the optical element is a gradient index lens array.
Claim 12
Dependent Claim
15 words
Apparatus as in claim 1, wherein the photoreceptor comprises a linear array of photosensitive elements.
Claim 13
Dependent Claim
15 words
Apparatus as in claim 1, wherein the photoreceptor comprises an area array of photosensitive elements.
Claim 14
Independent Claim
124 words
A method for correcting defocus of an image scanner having an optical element for providing optical image information to a photoreceptor comprising the steps of: determining the focus characteristics of the optical element at a plurality of levels of defocus throughout an expected range of focal errors; converting the defocus characteristics of the optical element at each defocus level to a set of correction data and electronically providing the correction data; determining at least one defocus level of the scanner; selecting at least one set of correction data corresponding to the at least one defocus level determined in the defocus level determination step; and electronically correcting an electrical image signal from the photoreceptor in accordance with the correction data selected in the selecting step.
Claim 15
Independent Claim
124 words
A method for correcting defocus of an image scanner having an optical element for providing optical image information to a photoreceptor comprising the steps of: determining the focus characteristics of the optical element at a plurality of levels of defocus throughout an expected range of focal errors; converting the defocus characteristics of the optical element at each defocus level to a set of correction data and electronically providing the correction data; determining at least one defocus level of the scanner; selecting at least one set of correction data corresponding to the at least one defocus level determined in the defocus level determination step; and electronically correcting an electrical image signal from the photoreceptor in accordance with the correction data selected in the selecting step.
Claim 16
Dependent Claim
31 words
A method as in claim 13, wherein the defocus level determining step comprises scanning a predetermined image and determining the defocus level from electrical image data representative of the predetermined image.
Claim 17
Dependent Claim
60 words
A method as in claim 13, wherein the step of determining the defocus characteristics of the optical element comprises determining the defocus characteristics for light at a plurality of different wavelengths and the step of determining the defocus level of the scanner includes determining the wavelength of light received by the optical element when the defocus level determination is made.
Claim 18
Dependent Claim
20 words
A method as in claim 13, wherein the step of electronically correcting the electrical image signal comprises filtering the signal.
Claim 19
Dependent Claim
45 words
A method as in claim 16, wherein the step of filtering the electrical image signal comprises determining filtering characteristics on the basis of at least one of the provided sets of correction data and the level of defocus determined in the defocus level determining step.
Claim 20
Dependent Claim
23 words
A method as in claim 13, wherein the step of electronically providing the correction data comprises storing the correction data in a memory.
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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) | 1997-04-25 | 1997-10-25 | 1998-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-25 | 2001-10-25 | 2002-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-25 | 2005-10-25 | 2006-04-26 | $7700.00 | Window Closed / Lapsed |