Patent US6952503B2 successfully refreshed from Google Patents.
US6952503B2
Expired / Lapsed
US
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Image processing apparatus and method
Assignee: Canon Inc
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Filing: 2002-09-19
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Granted: 2005-10-04
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Expires: 2022-09-19
Abstract
Abstract It is difficult properly to perform correction processing such as white balance adjustment and exposure compensation for all types of images. This invention provides a way in which white balance adjustment and exposure compensation are performed in accordance with image features by considering the arrangements of pixel values in the highlighted and shadow areas of an image. Proper correction processing can therefore be performed for any types of images.
Inventors
- 👤 Takahiro Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:37
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/40; G06T5/90; G06T5/92; H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6077
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
94 words
An image processing apparatus comprising: holding means for holding a plurality of conversion characteristics; calculation means for calculating an average luminance of an input image; obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; setting means for setting an exposure compensation condition on the basis of the target luminance; and correction means for correcting the input image on the basis of the exposure compensation condition.
Claim 2
Dependent Claim
94 words
An image processing apparatus comprising: holding means for holding a plurality of conversion characteristics; calculation means for calculating an average luminance of an input image; obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; setting means for setting an exposure compensation condition on the basis of the target luminance; and correction means for correcting the input image on the basis of the exposure compensation condition.
Claim 3
Dependent Claim
47 words
The apparatus according to claim 1 , wherein said calculation means selects a weak conversion characteristic when the highlight point is not less than a first threshold and the shadow point is not more than a second threshold, and selects a strong conversion characteristic in other cases.
Claim 4
Dependent Claim
17 words
The apparatus according to claim 2 , wherein the first threshold is larger than the second threshold.
Claim 5
Dependent Claim
142 words
An image processing apparatus comprising: first calculation means for calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; first setting means for setting a gradation correction condition on the basis of the white balance and the predetermined luminance; extraction means for extracting highlight and shadow points on the basis of a color distribution of an input image; second calculation means for calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and second setting means for setting an exposure compensation condition on the basis of the target luminance, wherein the apparatus corrects the input image on the basis of the gradation correction condition and the exposure compensation condition.
Claim 6
Dependent Claim
142 words
An image processing apparatus comprising: first calculation means for calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; first setting means for setting a gradation correction condition on the basis of the white balance and the predetermined luminance; extraction means for extracting highlight and shadow points on the basis of a color distribution of an input image; second calculation means for calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and second setting means for setting an exposure compensation condition on the basis of the target luminance, wherein the apparatus corrects the input image on the basis of the gradation correction condition and the exposure compensation condition.
Claim 7
Dependent Claim
29 words
The apparatus according to claim 4 , further comprising correction means for correcting the input image on the basis of the exposure compensation condition set by said setting means.
Claim 8
Dependent Claim
30 words
The apparatus according to claim 4 , further comprising holding means for holding a conversion characteristic to be referred to when a target luminance is calculated by said calculation means.
Claim 9
Dependent Claim
84 words
An image processing method comprising the steps of: holding a plurality of conversion characteristics; calculating an average luminance of an input image; obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; setting an exposure compensation condition on the basis of the target luminance; correcting the input image on the basis of the exposure compensation condition.
Claim 10
Dependent Claim
84 words
An image processing method comprising the steps of: holding a plurality of conversion characteristics; calculating an average luminance of an input image; obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; setting an exposure compensation condition on the basis of the target luminance; correcting the input image on the basis of the exposure compensation condition.
Claim 11
Dependent Claim
48 words
The method according to claim 7 , wherein said calculation step includes selecting a weak conversion characteristic when the highlight point is not less than a first threshold and the shadow point is not more than a second threshold, and selecting a strong conversion characteristic in other cases.
Claim 12
Dependent Claim
17 words
The method according to claim 8 , wherein the first threshold is larger than the second threshold.
Claim 13
Dependent Claim
107 words
A recording medium on which a program code for image correction processing is recorded, the program code comprising at least: code for holding a plurality of conversion characteristics; code for calculating an average luminance of an input image; code for obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; code for setting an exposure compensation condition on the basis of the target luminance; and code for correcting the input image on the basis of the exposure compensation condition.
Claim 14
Dependent Claim
107 words
A recording medium on which a program code for image correction processing is recorded, the program code comprising at least: code for holding a plurality of conversion characteristics; code for calculating an average luminance of an input image; code for obtaining means for obtaining a target luminance according to the average luminance by using one of the plurality of conversion characteristics, the one of the conversion characteristics being selected on the basis of the highlight and shadow points; code for setting an exposure compensation condition on the basis of the target luminance; and code for correcting the input image on the basis of the exposure compensation condition.
Claim 15
Dependent Claim
125 words
An image processing method comprising the steps of: calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; setting a gradation correction condition on the basis of the white balance and the predetermined luminance; extracting highlight and shadow points on the basis of a color distribution of an input image; calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and setting an exposure compensation condition on the basis of the target luminance, wherein the input image is corrected on the basis of the gradation correction condition and the exposure compensation condition.
Claim 16
Dependent Claim
125 words
An image processing method comprising the steps of: calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; setting a gradation correction condition on the basis of the white balance and the predetermined luminance; extracting highlight and shadow points on the basis of a color distribution of an input image; calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and setting an exposure compensation condition on the basis of the target luminance, wherein the input image is corrected on the basis of the gradation correction condition and the exposure compensation condition.
Claim 17
Dependent Claim
147 words
A recording medium on which a program code for image correction processing is recorded, the program code comprising at least: code for calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; code for setting a gradation correction condition on the basis of the white balance and the predetermined luminance; code for extracting highlight and shadow points on the basis of a color distribution of an input image; code for calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and code for setting an exposure compensation condition on the basis of the target luminance, wherein the input image is corrected on the basis of the gradation correction condition and the exposure compensation condition.
Claim 18
Dependent Claim
147 words
A recording medium on which a program code for image correction processing is recorded, the program code comprising at least: code for calculating white balance of an input image on the basis of pixels having luminances less than a predetermined luminance in the highlight area of the input image; code for setting a gradation correction condition on the basis of the white balance and the predetermined luminance; code for extracting highlight and shadow points on the basis of a color distribution of an input image; code for calculating an average luminance of the input image and calculating a target luminance on the basis of the average luminance and the highlight and shadow points; and code for setting an exposure compensation condition on the basis of the target luminance, wherein the input image is corrected on the basis of the gradation correction condition and the exposure compensation condition.
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| 3.5 Years (Year 4) | 2008-10-03 | 2009-04-04 | 2009-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-10-03 | 2013-04-04 | 2013-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-10-03 | 2017-04-04 | 2017-10-04 | $7700.00 | Window Closed / Lapsed |