US5822453A
Expired / Lapsed
US
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Method for estimating and adjusting digital image contrast
Assignee: Eastman Kodak Co
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Filing: 1996-12-10
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Granted: 1998-10-13
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Expires: 2016-12-10
Abstract
Abstract A method of estimating the scene contrast from a digital image, the method comprises the steps of: forming a Laplacian histogram distribution; determining, from the Laplacian histogram, first and second thresholds which eliminate substantially uniform areas or a substantially textured portion of the digital image; selecting pixels which are based on the first and second thresholds from the digital image; forming a histogram from the sampled pixels; computing a standard deviation of the sampled histogram; and estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Inventors
- 👤 Hsien-Che Lee
- 👤 Heemin Kwon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:43
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/90; G06T5/92; H; H04; H04N; H04N1/00; H04N1/40; H04N1/407; H04N1/4072; H04N1/4074
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
130 words
A method of estimating the scene contrast from a digital image, the method comprising the steps of: a) determining a Laplacian value for value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially uniform areas or substantially textured portion of the digital image; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) computing a standard deviation of the intensity histogram; and g) estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Claim 2
Independent Claim
130 words
A method of estimating the scene contrast from a digital image, the method comprising the steps of: a) determining a Laplacian value for value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially uniform areas or substantially textured portion of the digital image; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) computing a standard deviation of the intensity histogram; and g) estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Claim 3
Dependent Claim
28 words
The method of claim 1, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 4
Dependent Claim
22 words
The method of claim 1, wherein the step of selecting the pixels includes selecting the pixels that exceed substantially the first threshold.
Claim 5
Dependent Claim
24 words
The method of claim 1, wherein the step of selecting the pixels includes selecting the pixels that are less than substantially the second threshold.
Claim 6
Dependent Claim
24 words
The method of claim 1 further comprising the step of computing a tone scale transformation curve from the estimate contrast of the digital image.
Claim 7
Dependent Claim
42 words
The method of claim 5 further comprising the step of constructing the tone transformation curve by modifying the intensity histogram formed from the selected pixels so that a target histogram is generated which said target histogram is dependent on the digital image.
Claim 8
Dependent Claim
27 words
The method of claim 6 further comprising the step of constructing a tone transformation curve by convolving the intensity histogram with another pre-defined function with image-dependent parameters.
Claim 9
Dependent Claim
13 words
The method of claim 7, wherein the predefined function is a Gaussian distribution.
Claim 10
Dependent Claim
39 words
The method of claim 1 further comprising forming a target histogram from the intensity histogram by convolving the intensity histogram with a pre-defined function, and constructing a tone scale curve by transforming the intensity histogram to the target histogram.
Claim 11
Dependent Claim
28 words
The method of claim 9, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 12
Dependent Claim
22 words
The method of claim 9, wherein the step of selecting the pixels includes selecting the pixels that exceed substantially the first threshold.
Claim 13
Dependent Claim
24 words
The method of claim 9, wherein the step of selecting the pixels includes selecting the pixels that are less than substantially the second threshold.
Claim 14
Independent Claim
109 words
A method of estimating the scene contrast from a digital image, the method comprising the steps of: a) determining a Laplacian value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) forming a target histogram from the intensity histogram by convolving the intensity histogram with a pre-defined function; and g) constructing a tone scale curve by transforming the intensity histogram to the target histogram.
Claim 15
Independent Claim
109 words
A method of estimating the scene contrast from a digital image, the method comprising the steps of: a) determining a Laplacian value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) forming a target histogram from the intensity histogram by convolving the intensity histogram with a pre-defined function; and g) constructing a tone scale curve by transforming the intensity histogram to the target histogram.
Claim 16
Dependent Claim
23 words
The method as in claim 13, wherein the step of forming a target histogram includes convolving the intensity histogram with a Gaussian distribution.
Claim 17
Dependent Claim
34 words
The method as in claim 14, wherein the step of forming a target histogram includes convolving the intensity histogram with the Gaussian distribution having a standard deviation substantially the same as the sampled histogram.
Claim 18
Dependent Claim
49 words
The method as in claim 13 further comprising the step of computing a standard deviation of the intensity histogram and estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Claim 19
Dependent Claim
28 words
The method of claim 16, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 20
Dependent Claim
22 words
The method of claim 17, wherein the step of selecting the pixels includes selecting the pixels that exceed substantially the first threshold.
Claim 21
Dependent Claim
24 words
The method of claim 18, wherein the step of selecting the pixels includes selecting the pixels that are less than substantially the second threshold.
Claim 22
Dependent Claim
33 words
The method of claim 19 further comprising the step of constructing the tone transformation curve by modifying the intensity histogram formed from the selected pixels so that an image-dependent target histogram is generated.
Claim 23
Dependent Claim
101 words
A computer program product for excluding pixels from a uniform portion or a texture portion of a digital image, comprising a computer readable storage medium having a computer program stored thereon for performing the steps of: a) determining a Laplacian value for each pixel of the digital image; b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially the uniform portion or substantially the textured portion of the digital image; and d) selecting pixels which are based on the first and second thresholds from the digital image.
Claim 24
Dependent Claim
101 words
A computer program product for excluding pixels from a uniform portion or a texture portion of a digital image, comprising a computer readable storage medium having a computer program stored thereon for performing the steps of: a) determining a Laplacian value for each pixel of the digital image; b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially the uniform portion or substantially the textured portion of the digital image; and d) selecting pixels which are based on the first and second thresholds from the digital image.
Claim 25
Independent Claim
86 words
A method for excluding pixels from a uniform portion or a texture portion of a digital image, comprising the steps of: a) determining a Laplacian value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially the uniform portion or substantially the textured portion of the digital image; and d) selecting pixels which are based on the first and second thresholds from the digital image.
Claim 26
Independent Claim
86 words
A method for excluding pixels from a uniform portion or a texture portion of a digital image, comprising the steps of: a) determining a Laplacian value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially the uniform portion or substantially the textured portion of the digital image; and d) selecting pixels which are based on the first and second thresholds from the digital image.
Claim 27
Dependent Claim
28 words
The method of claim 22, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 28
Dependent Claim
141 words
A computer program product for estimating the scene contrast from a digital image, comprising: a computer readable storage medium having a computer program stored thereon for performing the steps of: a) determining a Laplacian value for each pixel of the digital image; b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially uniform areas or substantially textured portion of the digital image; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) computing a standard deviation of the intensity histogram; and g) estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Claim 29
Dependent Claim
141 words
A computer program product for estimating the scene contrast from a digital image, comprising: a computer readable storage medium having a computer program stored thereon for performing the steps of: a) determining a Laplacian value for each pixel of the digital image; b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds which eliminate substantially uniform areas or substantially textured portion of the digital image; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) computing a standard deviation of the intensity histogram; and g) estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Claim 30
Dependent Claim
31 words
The computer program product as in claim 24, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 31
Dependent Claim
25 words
The computer program product as in claim 24, wherein the step of selecting the pixels includes selecting the pixels that exceed substantially the first threshold.
Claim 32
Dependent Claim
27 words
The computer program product as in claim 24, wherein the step of selecting the pixels includes selecting the pixels that are less than substantially the second threshold.
Claim 33
Dependent Claim
27 words
The computer program product as in claim 24 further comprising the step of computing a tone scale transformation curve from the estimate contrast of the digital image.
Claim 34
Dependent Claim
45 words
The computer program product as in claim 28 further comprising the step of constructing the tone transformation curve by modifying the intensity histogram formed from the selected pixels so that a target histogram is generated which said target histogram is dependent on the digital image.
Claim 35
Dependent Claim
30 words
The computer program product as in claim 29 further comprising the step of constructing a tone transformation curve by convolving the intensity histogram with another pre-defined function with image-dependent parameters.
Claim 36
Dependent Claim
16 words
The computer program product as in claim 30, wherein the pre-defined function is a Gaussian distribution.
Claim 37
Dependent Claim
42 words
The computer program product as in claim 24 further comprising forming a target histogram from the intensity histogram by convolving the intensity histogram with a pre-defined function, and constructing a tone scale curve by transforming the intensity histogram to the target histogram.
Claim 38
Dependent Claim
31 words
The computer program product as in claim 32, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 39
Dependent Claim
25 words
The computer program product as in claim 32, wherein the step of selecting the pixels includes selecting the pixels that exceed substantially the first threshold.
Claim 40
Dependent Claim
27 words
The computer program product as in claim 32 wherein the step of selecting the pixels includes selecting the pixels that are less than substantially the second threshold.
Claim 41
Dependent Claim
122 words
A computer program product for estimating the scene contrast from a digital image, comprising: a computer readable storage medium having a computer program stored thereon for performing the steps of: a) determining a Laplacian value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) forming a target histogram from the intensity histogram by convolving the intensity histogram with a predefined function; and g) constructing a tone scale curve by transforming the intensity histogram to the target histogram.
Claim 42
Dependent Claim
122 words
A computer program product for estimating the scene contrast from a digital image, comprising: a computer readable storage medium having a computer program stored thereon for performing the steps of: a) determining a Laplacian value for each pixel of the digital image: b) forming a Laplacian histogram distribution based on the Laplacian values; c) determining, from the Laplacian histogram, first and second thresholds; d) selecting pixels which are based on the first and second thresholds from the digital image; e) forming an intensity histogram from the selected pixels; f) forming a target histogram from the intensity histogram by convolving the intensity histogram with a predefined function; and g) constructing a tone scale curve by transforming the intensity histogram to the target histogram.
Claim 43
Dependent Claim
25 words
The computer program product as in claim 36, wherein the step of forming a target histogram includes convolving the intensity histogram with a Gaussian distribution.
Claim 44
Dependent Claim
36 words
The computer program product as in claim 37, wherein the step of forming a target histogram includes convolving the intensity histogram with the Gaussian distribution having a standard deviation substantially the same as the sampled histogram.
Claim 45
Dependent Claim
51 words
The computer program product as in claim 36 further comprising the step of computing a standard deviation of the intensity histogram and estimating contrast of the digital image by comparing the computed standard deviation with a predetermined contrast for determining contrast of the input image in relationship with the predetermined contrast.
Claim 46
Dependent Claim
31 words
The computer program product as in claim 39, wherein the step of determining the first and second thresholds includes finding a local maxima of a second derivative of the Laplacian histogram.
Claim 47
Dependent Claim
25 words
The computer program product as in claim 40, wherein the step of selecting the pixels includes selecting the pixels that exceed substantially the first threshold.
Claim 48
Dependent Claim
27 words
The computer program product as in claim 41, wherein the step of selecting the pixels includes selecting the pixels that are less than substantially the second threshold.
Claim 49
Dependent Claim
36 words
The computer program product as in claim 42 further comprising the step of constructing the tone transformation curve by modifying the intensity histogram formed from the selected pixels so that an image-dependent target histogram is generated.
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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) | 2001-10-12 | 2002-04-13 | 2002-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-12 | 2006-04-13 | 2006-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-12 | 2010-04-13 | 2010-10-13 | $7700.00 | Window Closed / Lapsed |