Image analysis – Image enhancement or restoration – Intensity – brightness – contrast – or shading correction
Reexamination Certificate
1998-08-25
2001-02-27
Lee, Thomas D. (Department: 2624)
Image analysis
Image enhancement or restoration
Intensity, brightness, contrast, or shading correction
C382S312000, C358S461000
Reexamination Certificate
active
06195469
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus and, particularly, to such an apparatus which can simply correct the shading of an image produced by a two-dimensional sensor by converging light onto the two-dimensional sensor through a lens.
DESCRIPTION OF THE PRIOR ART
A chemiluminescence detecting system is known, which comprises the steps of selectively labeling a fixed high molecular substance such as a protein or a nucleic acid sequence with a labeling substance which generates chemiluminescent emission when it contacts a chemiluminescent substance, contacting the high molecular substance selectively labeled with the labeling substance and the chemiluminescent substance, photoelectrically detecting the chemiluminescent emission in the wavelength of visible light generated by the contact of the chemiluminescent substance and the labeling substance and producing digital image signals, effecting image processing thereon, and reproducing a chemiluminescent image on a display means such as a CRT or a recording material such as a photographic film, thereby obtaining information relating to the high molecular substance such as genetic information.
Further, a fluorescence system using a fluorescent substance as a labeling substance is known. According to this system, it is possible to study a genetic sequence, the expression level of a gene and to effect separation or identification of protein or estimation of the molecular weight or properties of protein or the like. For example, this system can perform a process including the steps of distributing a plurality of DNA fragments on a gel support by means of electrophoresis after a fluorescent dye was added to a solution containing a plurality of DNA fragments to be distributed or distributing a plurality of DNA fragments on a gel support containing a fluorescent dye or dipping a gel support on which a plurality of DNA fragments have been distributed by means of electrophoresis in a solution containing a fluorescent dye, thereby labeling the electrophoresed DNA fragments, exciting the fluorescent dye by a stimulating ray to cause it to release fluorescent light, detecting the released fluorescent light to produce an image and detecting the distribution of the DNA fragments on the gel support. This system can also perform a process including the steps of distributing a plurality of DNA fragments on a gel support by means of electrophoresis, denaturing the DNA fragments, transferring at least a part of the denatured DNA fragments onto a transfer support such as a nitrocellulose support by the Southern-blotting method, hybridizing a probe prepared by labeling target DNA and DNA or RNA complementary thereto with the denatured DNA fragments, thereby selectively labeling only the DNA fragments complementary to the probe DNA or probe RNA, exciting the fluorescent dye by a stimulating ray to cause it to release fluorescent light, detecting the released fluorescent light to produce an image and detecting the distribution of the target DNA on the transfer support. This system can further perform a process including the steps of preparing a DNA probe complementary to DNA containing a target gene labeled by a labeling substance, hybridizing it with DNA on a transfer support, combining an enzyme with the complementary DNA labeled by a labeling substance, causing the enzyme to contact a fluorescent substance, transforming the fluorescent substance to a fluorescent substance having fluorescent light releasing property, exciting the thus produced fluorescent substance by a stimulating ray to release fluorescent light, detecting the fluorescent light to produce an image and detecting the distribution of the target DNA on the transfer support. This fluorescence detecting system is advantageous in that a genetic sequence or the like can be easily detected without using a radioactive substance.
In the case where such chemiluminescent light or fluorescent light is converged onto the photo-electrical surface of a CCD camera by a lens to take a picture of a chemiluminescent image or a fluorescent image, the amount of light transmitted through the periphery portion of the lens is smaller than that through other portions of the lens. Shading is therefore generated in the image produced by the CCD camera. This makes it necessary to correct the thus generated shading by data processing.
However, since the shading is generated two-dimensionally and the shading has to be corrected using two-dimensional correction data, the volume of the correction data inevitably becomes great so that a memory having great capacity is needed.
A similar problem occurs not only in the case of correcting the shading in a chemiluminescent image or a fluorescent image but also in the case of correcting shading in an image produced by a two-dimensional sensor by converging light by a lens onto the two-dimensional sensor.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention is to provide an image processing apparatus which can simply correct the shading of an image produced by a two-dimensional sensor by converging light onto the two-dimensional sensor through a lens.
The above other objects of the present invention can be accomplished by an image processing apparatus comprising shading data calculating means for two-dimensionally mapping digitized data obtained by photo-electrically detecting uniform light converged by a lens by a two-dimensional sensor, thereby producing two-dimensional shading data whose density signal levels ellipse-like lower outwardly from a center pixel corresponding to the center of the lens to produce one-dimensional shading data from the density signal levels of the two-dimensional shading data on an arbitrary straight line extending outwardly from the center of the center pixel and calculating an angle &thgr; between the straight line used for producing the one-dimensional shading data and a longer axis or a shorter axis of the ellipse and a ratio of the longer axis to the shorter axis of the ellipse or the shorter axis to the longer axis of the ellipse, shading data storing means for storing the one-dimensional shading data, the angle &thgr; and the ratio of the longer axis to the shorter axis of the ellipse or the shorter axis to the longer axis of the ellipse, shading correction data producing means for producing shading correction data of each pixel based on the one-dimensional shading data, the angle &thgr; and the ratio of the longer axis to the shorter axis of the ellipse or the shorter axis to the longer axis of the ellipse stored in the shading data storing means in accordance with distance between the center of the center pixel and itself and an angle between a straight line passing through the center of the center pixel and itself and the longer axis or the shorter axis of the ellipse and shading correcting means for correcting shading of image data based on the shading correction data.
The inventors of the present invention conducted a study for accomplishing the above object of the present invention and, as a result, found that shading is generated in an image produced by a two-dimensional sensor, the density signal levels of which ellipse-like lower from the center of the center pixel corresponding to the center of a lens depending on the convergence characteristics of the lens, and the shape and arrangement of the photo-electrical elements of the two-dimensional sensor. Therefore, according to the present invention, digitized data obtained by photo-electrically detecting uniform light converged by a lens by a two-dimensional sensor are two-dimensionally mapped by the shading data calculating means, thereby producing the two-dimensional shading data, and one-dimensional shading data is produced from the density signal levels of the two-dimensional shading data on an arbitrary straight line extending outwardly from the center of the center pixel. The angle &thgr; between the straight line used for producing the one-dimensional shading data and the longer axis or the shorter axi
Nishioka Yukinori
Umeda Tomoaki
Chen Wen Peng
Fuji Photo Film Co. , Ltd.
Lee Thomas D.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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