US6845181B2
Expired / Lapsed
US
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Method for processing a digital image to adjust brightness
Assignee: Monument Peak Ventures LLC
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Filing: 2001-07-12
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Granted: 2005-01-18
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Expires: 2021-07-12
Abstract
Abstract A method of processing a digital image, including the steps of applying an initial scene balance algorithm to the digital image to produce an initial scene balanced digital image; detecting skin colored pixels in the initial scene balanced digital image, calculating a brightness adjustment amount based on a statistic of the detected skin colored pixels; and applying the brightness adjustment amount to the scene balanced digital image to produce a processed digital image having improved overall brightness.
Inventors
- 👤 Michael W. Dupin
- 👤 Jiebo Luo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:58
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/40; G06T5/90; G06T5/92; G06T7/00; G06T7/10; G06T7/136; H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6027; H04N1/62; H04N1/628; G06T2207/00; G06T2207/10; G06T2207/10024
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
81 words
A method of processing a digital image, comprising the steps of: a) applying an initial scene balance algorithm to the digital image to produce an initial scene balanced digital image; b) detecting skin colored pixels in the initial scene balanced digital image; c) calculating a brightness adjustment amount based on a statistic of the detected skin colored pixels; and d) applying the brightness adjustment amount to the scene balanced digital image to produce a processed digital image having improved overall brightness.
Claim 2
Independent Claim
81 words
A method of processing a digital image, comprising the steps of: a) applying an initial scene balance algorithm to the digital image to produce an initial scene balanced digital image; b) detecting skin colored pixels in the initial scene balanced digital image; c) calculating a brightness adjustment amount based on a statistic of the detected skin colored pixels; and d) applying the brightness adjustment amount to the scene balanced digital image to produce a processed digital image having improved overall brightness.
Claim 3
Dependent Claim
49 words
The method claimed in claim 1 , wherein the step of calculating a brightness adjustment amount comprises the steps of: c1) calculating a center weighted average of the brightness of the detected skin colored pixels, c2) calculating the brightness adjustment amount as a function of the center weighted average.
Claim 4
Dependent Claim
27 words
The method claimed in claim 2 , wherein the function is a linear function: Brightness Adjustment=B * (center weighted average−A), where A and B are predetermined constants.
Claim 5
Dependent Claim
13 words
The method claimed in claim 3 wherein the function is a nonlinear function.
Claim 6
Dependent Claim
19 words
The method claimed in claim 1 , wherein the initial scene balance algorithm is the Evans gray world algorithm.
Claim 7
Dependent Claim
20 words
The method claimed in claim 1 , wherein the initial scene balance algorithm is the LATD brightness scene balance algorithm.
Claim 8
Dependent Claim
20 words
The method claimed in claim 6 , wherein the initial scene balance algorithm includes the Kwon color scene balance algorithm.
Claim 9
Dependent Claim
77 words
The method claimed in claim 1 , wherein the step of detecting skin colored pixels in the initial scene balanced digital image comprises the steps of: b1) for each pixel in the digital image, calculating a probability that the pixel is a skin colored pixel; b2) determining a skin color probability threshold based on a statistic derived from the digital image, and c2) designating any pixels having a probability greater than the threshold as skin colored pixels.
Claim 10
Dependent Claim
73 words
The method claimed in claim 8 , wherein the digital image is expressed in RGB coordinates and the probability that the pixel is a skin colored pixel is calculated by the steps of: b1a) converting the digital image from RGB to Lst coordinates; and b1b) determining the skin color probability using a predetermined skin probability density function expressed in Lst coordinates developed from a population of images containing skin and non-skin colored pixels.
Claim 11
Dependent Claim
105 words
The method claimed in claim 8 , wherein the step of determining a skin color probability threshold includes the steps of: b2a) forming a skin probability map using skin color probability values of all the pixels in the image, b2b) computing gradient values from the skin probability map; b2c) selecting pixels having gradient values greater than a predetermined value; b2d) forming a histogram of skin probability values using only the selected pixels from the previous step, b2e) locating a valley point in the histogram; and b2f) determining the skin color probability threshold as the skin probability value at the located valley point of the histogram.
Claim 12
Dependent Claim
36 words
The method claimed in claim 1 , further comprising the step of counting the number of detected skin colored pixels, and performing the brightness adjustment only if a minimum number of skin colored pixels are detected.
Claim 13
Dependent Claim
22 words
The method claimed in claim 1 , wherein the digital image is obtained by digitization of a picture originally captured on film.
Claim 14
Dependent Claim
21 words
The method claimed in claim 1 , further includes printing the processed digital image having improved overall brightness on photographic paper.
Claim 15
Dependent Claim
13 words
A computer program product for performing the method claimed in claim 1 .
Claim 16
Dependent Claim
87 words
A computer system for processing a digital image, comprising: a) means for applying an initial scene balance algorithm to the digital image to produce an initial scene balanced digital image, b) means for detecting skin colored pixels in the initial scene balanced digital image; c) means for calculating a brightness adjustment amount based on a statistic of the detected skin colored pixels, and d) means for applying the brightness adjustment amount to the scene balanced digital image to produce a processed digital image having improved overall brightness.
Claim 17
Dependent Claim
87 words
A computer system for processing a digital image, comprising: a) means for applying an initial scene balance algorithm to the digital image to produce an initial scene balanced digital image, b) means for detecting skin colored pixels in the initial scene balanced digital image; c) means for calculating a brightness adjustment amount based on a statistic of the detected skin colored pixels, and d) means for applying the brightness adjustment amount to the scene balanced digital image to produce a processed digital image having improved overall brightness.
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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) | 2008-01-18 | 2008-07-19 | 2009-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-01-18 | 2012-07-19 | 2013-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-01-18 | 2016-07-19 | 2017-01-18 | $7700.00 | Window Closed / Lapsed |