Techniques for modifying image field data obtained using illumination sources
First Claim
Patent Images
1. A method of modifying data of an image of an object field being electronically captured, comprising:
- capturing two or more image data sets of the object field with different levels of artificial illumination;
generating, from the captured image data sets, illumination correction data that corrects for the artificial illumination being non-uniform across the object field;
acquiring an image data set of interest of the object field, where the resolution of the data set of interest is greater than the resolution of at least one of the other two or more image data sets; and
applying the illumination correction data set to the image data set of interest to obtain an illumination-corrected image data set of interest, thereby compensating for variations in the intensity across the image field that are attributable to the artificial illumination of the object field, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from one of the image data sets captured at a first artificial illumination level, and intensity of a corresponding image data point of interest from another of the image data sets captured at a second artificial illumination level, where such difference is further multiplied by a value resulting from dividing one of the first and second artificial illumination level by the other.
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Abstract
Techniques for modifying data of an image that can be implemented in a digital camera, video image capturing device and other optical systems are provided to correct for non-uniform illumination and/or effects of saturation appearing in data obtained using one or more artificial illumination sources. In an implementation, correction factors are derived using data from at least two images that have been captured with different illumination levels of the object scene and close in time to the capture of the image of interest. Typically, the image of interest is of higher resolution than at least one of the at least two images.
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Citations
32 Claims
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1. A method of modifying data of an image of an object field being electronically captured, comprising:
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capturing two or more image data sets of the object field with different levels of artificial illumination; generating, from the captured image data sets, illumination correction data that corrects for the artificial illumination being non-uniform across the object field; acquiring an image data set of interest of the object field, where the resolution of the data set of interest is greater than the resolution of at least one of the other two or more image data sets; and applying the illumination correction data set to the image data set of interest to obtain an illumination-corrected image data set of interest, thereby compensating for variations in the intensity across the image field that are attributable to the artificial illumination of the object field, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from one of the image data sets captured at a first artificial illumination level, and intensity of a corresponding image data point of interest from another of the image data sets captured at a second artificial illumination level, where such difference is further multiplied by a value resulting from dividing one of the first and second artificial illumination level by the other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of modifying an image field being electronically captured using artificial illumination, comprising:
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directing the capture of a first image data set of the image field corresponding to a first illumination level; directing the capture of a second image data set of the image field corresponding to a second illumination level different from the first illumination level; designating an image data set of interest of the image field, where the resolution of the data set of interest is greater than the resolution of at least one of the other two image data sets; calculating a relationship between the first and second illumination levels; generating an illumination correction data set from the first and second image data sets, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from the first image data set captured at the first illumination level, and intensity of a corresponding image data point of interest from the second image data set captured at the second illumination level, where such difference is further multiplied by a value resulting from dividing one of the first and second illumination levels by the other; and applying the illumination correction data set and the illumination level relationship to the image data set of interest to obtain an illumination-corrected image data set of interest, thereby compensating for uneven distribution of light across the image field. - View Dependent Claims (18, 19)
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20. A method of modifying an image field being electronically captured, comprising:
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capturing a first image data set of the image field corresponding to a first artificial illumination level; capturing a second image data set of the image field corresponding to a second artificial illumination level different from said first illumination level; generating, from the captured first and second image data sets, illumination correction data as a function of position to compensate for uneven distribution of light from the illumination source, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from the first image data set captured at the first illumination level, and intensity of a corresponding image data point of interest from the second image data set captured at the second illumination level, where such difference is further multiplied by a value resulting from dividing one of the first and second illumination levels by the other; obtaining an image data set of interest of the image field, where the resolution of the data set of interest is greater than the resolution of the other one or more image data sets; and applying the illumination correction data set to the image data set of interest to obtain an illumination-corrected image data set of interest, thereby compensating for variations in the intensity across the artificial illumination. - View Dependent Claims (21, 22)
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23. A method of modifying an image field being electronically captured, comprising:
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capturing two or more image data sets of the image field; generating, from the captured image data sets, illumination correction data that corrects for (1) any variations of intensity of artificial illumination of the image field as a function of position across the image field, and (2) any areas of saturation of the image field, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from one of the image data sets captured at a first artificial illumination level, and intensity of a corresponding image data point of interest from another of the image data sets captured at a second artificial illumination level, where such difference is further multiplied by a value resulting from dividing the second artificial illumination level by the first artificial illumination level; acquiring an image data set of interest of the image field; and applying the illumination correction data set to the image data set of interest to obtain a corrected image data set of interest.
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24. A method of correcting a set of data of an image of interest obtained by use of a photosensor, comprising:
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capturing first and second sets of data of respective first and second images on the photosensor of an object scene illuminated with first and second levels of artificial illumination that are different from each other, acquiring the set of data of the image of interest with the photosensor when the object scene is illuminated with a third level of artificial illumination that is between and different from the first and second levels, and utilizing illumination correction data generated from the first and second sets of data to correct the set of data of the image of interest for any areas of negative or positive saturation of the photosensor by the image of interest, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from the first set of data captured at the first level of artificial illumination, and intensity of a corresponding image data point of interest from the second set of data captured at the second level of artificial illumination, where such difference is further multiplied by a value resulting from dividing one of the first and second levels of artificial illumination by the other. - View Dependent Claims (25, 26)
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27. An integrated circuit chip containing circuits capable of receiving and processing data obtained from a two-dimensional optical image detector, comprising:
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said circuits functioning to capture two or more image data sets of an image field as illuminated by an illumination source, and that acquires an image data set of interest of the image field, where the resolution of the data set of interest is greater than the resolution of at least one of the other two or more image data sets; and said circuits further functioning to generate, from the captured image data sets, illumination correction data that corrects for artificial illumination of the image field as a function of position across the image field, and that applies the illumination correction data to the image data set of interest to obtain an illumination-corrected image data set of interest, thereby compensating for variations in the intensity across the image field that are attributable to the artificial illumination, wherein the illumination correction data is based at least in part on a difference between intensity of an image data point of interest from a first set of data captured at a first level of artificial illumination, and intensity of a corresponding image data point of interest from a second set of data captured at a second level of artificial illumination, where such difference is further multiplied by a value resulting from dividing one of the first and second levels of artificial illumination by the other. - View Dependent Claims (28)
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29. A digital camera, comprising within a single unit:
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a photodetector system that captures data of an image cast thereon, an optical system capable of casting an image of an object scene onto the photodetector, a flash illumination device capable of illuminating the object scene with at least first and second levels of illumination, a controller that causes at least first and second sets of image data of the object scene to be captured with respective first and second levels of illumination, and a signal processor capable of; determining, from the captured first and second sets of data, variations in intensity in an image cast on the photodetector system, calculating therefrom correction data that corrects for uneven intensity distribution across the illumination of the object scene by the flash illumination device, wherein the correction data is based at least in part on a difference between intensity of an image data point of interest from the first set of data captured at a first level of artificial illumination, and intensity of a corresponding image data point of interest from the second set of data captured at a second level of artificial illumination, where such difference is further multiplied by a value resulting from dividing one of the first and second levels of artificial illumination by the other, storing the correction data, and thereafter combining the stored correction data with data of at least one other image captured by the photodetector system in order to correct for variations in the intensity across said at least one other image that are attributable to the flash illumination, wherein said at least one other image is captured by the photodetector system with a resolution that is higher than the resolution of the first or second sets of data.
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30. A digital camera, comprising within a single unit:
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a photodetector system that captures data of an image cast thereon, an optical system capable of casting an image of an object scene onto the photodetector, a flash illumination device capable of illuminating the object scene with at least first, second and third levels of illumination, wherein the second level is greater than the first level and the third level is greater than the second level, a controller that causes at first, second and third sets of image data of the object scene to be captured with respective first, second and third levels of illumination, and a signal processor that operates to; calculate, from the captured first and third sets of data, data that corrects for any negative or positive saturation of the photodetector system in the second set of data, at least temporarily store the saturation correction data, thereafter combine the stored saturation correction data with the second set of data in order to correct for effects of any negative or positive saturation therein, determine, from the captured first and third sets of data, variations in intensity in an image cast on the photodetector system, calculate therefrom intensity correction data that corrects for uneven intensity distribution across the illumination of the object scene by the flash illumination device, wherein the intensity correction data is based at least in part on a difference between intensity of an image data point of interest from a first set of data captured at a first level of artificial illumination, and intensity of a corresponding image data point of interest from a second set of data captured at a second level of artificial illumination, where such difference is further multiplied by a value resulting from dividing one of the first and second levels of artificial illumination by the other, at least temporarily store the intensity correction data, and thereafter combine the stored correction data with second set of data in order to correct for variations in the intensity across the image of the second set of data that are attributable to non-uniformity of the flash illumination. - View Dependent Claims (31, 32)
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Specification