Image analysis – Image enhancement or restoration – Intensity – brightness – contrast – or shading correction
Reexamination Certificate
2000-10-10
2002-12-24
Rogers, Scott (Department: 2624)
Image analysis
Image enhancement or restoration
Intensity, brightness, contrast, or shading correction
C382S275000, C382S112000, C356S239100, C356S239700, C356S237200
Reexamination Certificate
active
06498867
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to the field of image processing, and more particularly to a method and apparatus for differential illumination image-capturing and defect handling.
BACKGROUND OF THE INVENTION
Image scanners, such as flatbed scanners, are widely used to convert documents, such as papers, images, photographs, negatives and the like, into electronic representations of the document or digital images. This is typically done by placing the document on a glass platen, illuminating the document with visible light and moving an imager relative to the document to record the intensity of light reflected from each minute location of the document and to process that information to form the digital image of the document. The digital image can then be stored, altered electronically, or printed.
A drawback of a conventional scanning system is that defects on the document such as dust, lint, and scratches, as well as defects in the scanning system, such as platen scratches, smudges, dust and fingerprints result in a degraded electronic representation or digital image. Also, when scanning matte finished photographs, many conventional scanners have a tendency to produce lines in the digital image. This is because matte finished photographs have a raised surface texture that causes shadows to be cast in between the raised area.
SUMMARY OF THE INVENTION
Accordingly, it may be appreciated that a need has arisen for a method and system for reducing defects in a digital image. In accordance with the teachings of the present invention, a method and system for differential illumination image-capturing and defect handling is provided which substantially eliminates or reduces the disadvantages and problems associated with conventional imaging systems.
In one embodiment of the present invention, an image processing system is provided. The system includes a first light source operable to illuminate a document in a first direction and a second light source operable to illuminate the document from a second direction. Also included is a sensing device operable to detect light from the first and second light sources after interaction with the document. A processor receives information from the sensing device and produces an image and image defects.
In another implementation of the present invention, a method for determining defects on a document is disclosed. In a first step, a first image record based on light influenced by the document from a first light source is obtained. In a second step, a second image record based on light influenced by the document from a second light source is obtained. Next, a maximum pixel intensity record is obtained by comparing the first and second image records and selecting the highest pixel intensity value for a given pixel location. Then, a minimum pixel intensity record is obtained by comparing the first and second image records and selecting the lowest pixel intensity value for a given pixel location. Next, a difference record is obtained by subtracting the minimum pixel intensity record from the maximum pixel intensity value. Next, the center of a defect region is obtained by locating localized minimums in the difference record. Finally, defect boundaries are determined based on the difference record.
The present invention provides various technical advantages over conventional imaging systems. For example, one technical advantage is that the effects of defects can be substantially removed from a digital image. Another technical advantage is that documents with textured surfaces can be scanned more accurately then with many conventional systems. Another technical advantage is that at least two image datasets, corresponding to illumination from at least two separately illuminated light sources can be acquired. Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions and claims.
REFERENCES:
patent: 4260899 (1981-04-01), Baker
patent: 4265545 (1981-05-01), Slaker
patent: 4301469 (1981-11-01), Modeen et al.
patent: 4302108 (1981-11-01), Timson
patent: 4462860 (1984-07-01), Szmanda
patent: 4670779 (1987-06-01), Nagano
patent: 4677465 (1987-06-01), Alkofer
patent: 4680638 (1987-07-01), Childs
patent: 4700229 (1987-10-01), Herrmann et al.
patent: 4741621 (1988-05-01), Taft et al.
patent: 4775238 (1988-10-01), Weber
patent: 4796061 (1989-01-01), Ikeda et al.
patent: 4814630 (1989-03-01), Lim
patent: 4821114 (1989-04-01), Gebhardt
patent: 4845551 (1989-07-01), Matsumoto
patent: 4933566 (1990-06-01), Masaaki et al.
patent: 4937720 (1990-06-01), Kirchberg
patent: 4969045 (1990-11-01), Haruki et al.
patent: 4972091 (1990-11-01), Cielo et al.
patent: 4989973 (1991-02-01), Noso et al.
patent: 4994918 (1991-02-01), Lingemann
patent: 5003379 (1991-03-01), Moore, Jr. et al.
patent: 5010401 (1991-04-01), Murakami et al.
patent: 5047968 (1991-09-01), Carrington et al.
patent: 5058982 (1991-10-01), Katzir
patent: 5091972 (1992-02-01), Kwon et al.
patent: 5097521 (1992-03-01), Massmann
patent: 5149960 (1992-09-01), Dunne et al.
patent: 5155596 (1992-10-01), Kurtz et al.
patent: 5200817 (1993-04-01), Birnbaum
patent: 5266805 (1993-11-01), Edgar
patent: 5267030 (1993-11-01), Giorgianni et al.
patent: 5291286 (1994-03-01), Murakami et al.
patent: 5311310 (1994-05-01), Jozawa et al.
patent: 5335086 (1994-08-01), Kitamura
patent: 5371542 (1994-12-01), Pauli et al.
patent: 5447811 (1995-09-01), Buhr et al.
patent: 5448380 (1995-09-01), Park
patent: 5452018 (1995-09-01), Capitant et al.
patent: 5465153 (1995-11-01), Yoshihara et al.
patent: 5465155 (1995-11-01), Edgar
patent: 5477345 (1995-12-01), Tse
patent: 5509086 (1996-04-01), Edgar et al.
patent: 5516608 (1996-05-01), Hobbs et al.
patent: 5552904 (1996-09-01), Ryoo et al.
patent: 5561611 (1996-10-01), Avinash
patent: 5565931 (1996-10-01), Girod
patent: 5568270 (1996-10-01), Endo
patent: 5581376 (1996-12-01), Harrington
patent: 5582961 (1996-12-01), Giorgianni et al.
patent: 5583950 (1996-12-01), Prokoski
patent: 5589887 (1996-12-01), Wischermann
patent: 5608547 (1997-03-01), Nakatani et al.
patent: 5641596 (1997-06-01), Gray et al.
patent: 5666443 (1997-09-01), Kumashiro
patent: 5673336 (1997-09-01), Edgar et al.
patent: 5721624 (1998-02-01), Kumashiro et al.
patent: 5726773 (1998-03-01), Mehlo et al.
patent: 5729631 (1998-03-01), Wober et al.
patent: 5771107 (1998-06-01), Fujimoto et al.
patent: 5808674 (1998-09-01), Adams, Jr. et al.
patent: 5892595 (1999-04-01), Yamakawa et al.
patent: 5923042 (1999-07-01), Mietta et al.
patent: 5930388 (1999-07-01), Murakami et al.
patent: 5963662 (1999-10-01), Vachtsevanos et al.
patent: 5969372 (1999-10-01), Stavely et al.
patent: 5979011 (1999-11-01), Miyawaki et al.
patent: 5982941 (1999-11-01), Loveridge et al.
patent: 5982951 (1999-11-01), Katayama et al.
patent: 5991444 (1999-11-01), Burt et al.
patent: 6005987 (1999-12-01), Nakamura et al.
patent: 6057040 (2000-05-01), Hage
patent: 6075905 (2000-06-01), Herman et al.
patent: 6078051 (2000-06-01), Banton et al.
patent: 6078701 (2000-06-01), Hsu et al.
patent: 6101273 (2000-08-01), Matama
patent: 6128416 (2000-10-01), Oura
patent: 6239886 (2001-05-01), Klassen et al.
patent: 28 21 868 (1979-11-01), None
patent: 196 36 867 (1998-01-01), None
patent: 1 547 811 (1979-06-01), None
patent: 0 422 220 (1991-04-01), None
patent: 0 482 790 (1992-04-01), None
patent: 0 527 097 (1993-02-01), None
patent: 0 569 142 (1993-11-01), None
patent: 0 624 848 (1994-11-01), None
patent: 0 669 753 (1995-08-01), None
patent: 0 716 538 (1996-06-01), None
patent: 0 751 670 (1997-01-01), None
patent: 0 768 621 (1997-04-01), None
patent: 0 794 454 (1997-09-01), None
patent: 0 816 833 (1998-01-01), None
patent: 0 816 833 (1998-08-01), None
patent: 0 893 914 (1999-01-01), None
patent: 0 930 498 (1999-07-01), None
patent: 2 283 633 (1995-05-01), None
patent: 4-291139 (1992-10-01), None
patent: 11185028 (1999-07-01), None
patent: 2000-13604 (2000-01-01), None
patent: 2000-196813 (2000-07-01), None
patent: WO 84/02019 (1984-05-01), None
patent: WO 89/06890 (1989-07-01), None
pate
Dundon Thomas A.
Edgar Albert D.
Potucek Martin
Applied Science Fiction Inc.
Dinsmore & Shohl LLP
Rogers Scott
LandOfFree
Method and apparatus for differential illumination... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for differential illumination..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for differential illumination... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2968146