US7043090B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Enhancing the tonal characteristics of digital images using expansive and compressive tone scale functions
Assignee: Monument Peak Ventures LLC
•
Filing: 2002-10-02
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Granted: 2006-05-09
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Expires: 2022-10-02
Abstract
Abstract A method of enhancing the tonal characteristics of a digital image, includes receiving a source digital image including a plurality of pixels; producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values, wherein the classification categories include expansive and compressive; and using the tone scale function, the source digital image, and a spatial filter to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without a spatial filter to produce the enhanced digital image when the tone scale function has been classified as expansive.
Inventors
- 👤 Edward B. Gindele
- 👤 Andrew C. Gallagher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:20
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/90; G06T5/92; G06T5/40; G06V; G06V10/00; G06V10/20; G06V10/30
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
146 words
A method of enhancing the tonal characteristics of a digital image, comprising the steps of: a) receiving a source digital image including a plurality of pixels; b) producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; c) classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values, wherein the classification categories include expansive and compressive; and d) using the tone scale function, the source digital image, and a spatial filter to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without a spatial filter to produce the enhanced digital image when the tone scale function has been classified as expansive.
Claim 2
Independent Claim
146 words
A method of enhancing the tonal characteristics of a digital image, comprising the steps of: a) receiving a source digital image including a plurality of pixels; b) producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; c) classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values, wherein the classification categories include expansive and compressive; and d) using the tone scale function, the source digital image, and a spatial filter to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without a spatial filter to produce the enhanced digital image when the tone scale function has been classified as expansive.
Claim 3
Dependent Claim
28 words
The method of claim 1 using a sigmoid shaped rendering function independent of the source digital image and the enhanced digital image to produce a rendered digital image.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein step (b) further includes using the pixels of the source digital image to produce the tone scale function.
Claim 5
Dependent Claim
32 words
The method of claim 1 wherein step (b) further includes using the pixels of the source digital image to produce a histogram and using the histogram to produce the tone scale function.
Claim 6
Dependent Claim
47 words
The method of claim 4 wherein the tone scale function maps a fixed percentile of the histogram to a predetermined output value corresponding to a first predetermined density and a different fixed percentile of the histogram to a predetermined output value corresponding to a second predetermined density.
Claim 7
Dependent Claim
29 words
The method of claim 1 wherein the source digital image is in a luminance-chrominance representation including a luminance digital image channel and at least two chrominance digital image channels.
Claim 8
Dependent Claim
89 words
The method of claim 6 wherein step (d) further includes the steps of: i) using the spatial filter to produce a first and second signal from the luminance digital image channel such that when the first and second signals are added together the resultant signal would be equal to the luminance digital image channel; ii) using the tone scale function and the first signal to produce a modified first signal; and iii) combining the modified first signal with the second signal to produce a modified luminance digital image channel.
Claim 9
Dependent Claim
22 words
The method of claim 1 wherein the source digital image includes pixels corresponds to at least three different color digital image channels.
Claim 10
Dependent Claim
108 words
The method of claim 8 wherein step (d) further includes the steps of: i) using the spatial filter to produce a first and second signal from each color digital image channel such that when the first and second signals are added together the resultant signal would be equal to the color digital image channel; ii) using the tone scale function and the first signal from each color digital image channel to produce a modified first signal for each color digital image channel; and iii) combining the modified first signal with the corresponding second signal from each color digital image channel to produce a modified color digital image channel.
Claim 11
Dependent Claim
22 words
The method of claim 1 wherein the pixel values of the source digital image have a logarithmic relationship to original scene intensities.
Claim 12
Dependent Claim
20 words
The method of claim 1 wherein the tone scale function is adjusted by a user controlling at least one parameter.
Claim 13
Dependent Claim
99 words
The method of claim 1 wherein step (b) further includes producing the tone scale function having a highlight tone scale segment and a shadow tone scale segment defined relative to a reference point on the tone scale function, wherein: i) the highlight tone scale segment is defined by a different mathematical function than the shadow tone scale segment; ii) the highlight tone scale segment is defined for points that are equal to or greater than the reference point; and iii) the shadow tone scale segment is defined for points that are equal to or less than the reference point.
Claim 14
Dependent Claim
136 words
The method of claim 12 further including the steps of: classifying the highlight tone scale segment into one of two or more categories based on the effect the highlight tone scale segment will have on the corresponding numerical range of pixel values, wherein the classification categories include expansive and compressive; classifying the shadow tone scale segment into two or more categories based on the effect the shadow tone scale segment will have on the corresponding numerical range of pixel values of a processed digital image, wherein the classification categories include expansive and compressive; classifying the tone scale function as compressive when either the highlight or shadow tone scale segment has been classified as compressive and classifying the tone scale function as expansive when both the highlight and shadow tone scale segments have been classified as expansive.
Claim 15
Dependent Claim
23 words
The method of claim 12 wherein the slopes of the highlight and shadow tone scale segments are each equal at the reference point.
Claim 16
Dependent Claim
22 words
The method of claim 12 wherein the slopes of the highlight and shadow tone scale segments are unequal at the reference point.
Claim 17
Dependent Claim
18 words
The method of claim 12 wherein the tone scale function has an inflection point at the reference point.
Claim 18
Dependent Claim
19 words
The method of claim 12 wherein the reference point is calculated using the pixels of the source digital image.
Claim 19
Dependent Claim
33 words
The method of claim 12 further including the step of using the pixels of the source digital image to produce a histogram and using the histogram to produce the highlight tone scale segment.
Claim 20
Dependent Claim
28 words
The method of claim 18 wherein the highlight tone scale segment maps a fixed percentile of the histogram to a predetermined output value corresponding to a predetermined density.
Claim 21
Dependent Claim
33 words
The method of claim 12 further including the step of using the pixels of the source digital image to produce a histogram and using the histogram to produce the shadow tone scale segment.
Claim 22
Dependent Claim
28 words
The method of claim 20 wherein the shadow tone scale segment maps a fixed percentile of the histogram to a predetermined output value corresponding to a predetermined density.
Claim 23
Independent Claim
232 words
A method of enhancing the tonal characteristics of a digital image, comprising the steps of: a) receiving a source digital image including a plurality of pixels; b) producing a tone scale function having a highlight tone scale segment and a shadow tone scale segment defined relative to a reference point on the tone scale function, and that is adapted to operate on the source digital image to improve its tonal characteristics, wherein: i) the highlight tone scale segment is defined by a different mathematical function than the shadow tone scale segment; ii) the highlight tone scale segment is defined for points that are equal to or greater than the reference point; and iii) the shadow tone scale segment is defined for points that are equal to or less than the reference point; c) classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values, wherein the classification categories include expansive and compressive; and d) using a spatial filter, the tone scale function, and the source digital image to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without the spatial filter to produce an enhanced digital image when the tone scale function has been classified as expansive.
Claim 24
Independent Claim
232 words
A method of enhancing the tonal characteristics of a digital image, comprising the steps of: a) receiving a source digital image including a plurality of pixels; b) producing a tone scale function having a highlight tone scale segment and a shadow tone scale segment defined relative to a reference point on the tone scale function, and that is adapted to operate on the source digital image to improve its tonal characteristics, wherein: i) the highlight tone scale segment is defined by a different mathematical function than the shadow tone scale segment; ii) the highlight tone scale segment is defined for points that are equal to or greater than the reference point; and iii) the shadow tone scale segment is defined for points that are equal to or less than the reference point; c) classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values, wherein the classification categories include expansive and compressive; and d) using a spatial filter, the tone scale function, and the source digital image to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without the spatial filter to produce an enhanced digital image when the tone scale function has been classified as expansive.
Claim 25
Independent Claim
177 words
A method of enhancing the tonal characteristics of a digital image, comprising the steps of: a) receiving a source digital image in an RGB representation including a red, green, and blue digital image channel each digital image channel including a plurality of pixels; b) producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; c) classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values wherein the classification categories include expansive and compressive; d) transforming the source digital image into a luminance-chrominance representation; and e) using a spatial filter, the tone scale function, and the luminance-chrominance representation of the source digital image to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without the spatial filter to produce the enhanced digital image when the tone scale function has been classified as expansive.
Claim 26
Independent Claim
177 words
A method of enhancing the tonal characteristics of a digital image, comprising the steps of: a) receiving a source digital image in an RGB representation including a red, green, and blue digital image channel each digital image channel including a plurality of pixels; b) producing a tone scale function that can be used to enhance the tonal characteristics of the source digital image; c) classifying the tone scale function into one of two or more categories based on the effect the tone scale function will have on the numerical range of pixel values wherein the classification categories include expansive and compressive; d) transforming the source digital image into a luminance-chrominance representation; and e) using a spatial filter, the tone scale function, and the luminance-chrominance representation of the source digital image to produce an enhanced digital image when the tone scale function has been classified as compressive, and using the tone scale function and the source digital image without the spatial filter to produce the enhanced digital image when the tone scale function has been classified as expansive.
Claim 27
Dependent Claim
28 words
A computer storage product having at least one computer storage medium having instructions stored therein causing one or more computers to perform the method of claim 1 .
Claim 28
Dependent Claim
28 words
A computer storage product having at least one computer storage medium having instructions stored therein causing one or more computers to perform the method of claim 22 .
Claim 29
Dependent Claim
28 words
A computer storage product having at least one computer storage medium having instructions stored therein causing one or more computers to perform the method of claim 23 .
References Cited (Backward Citations)
US4731671A
Cited
US4745465A
Cited
DE4126751A1
Cited
US5300381A
Cited
US5568571A
Cited
US5432870A
Cited
US5515056A
Cited
US5991457A
Cited
EP0809209A2
Cited
US6285798B1
Cited
US6317521B1
Cited
US6282311B1
Cited
US6167165A
Cited
US6408103B1
Cited
US6600833B1
Cited
US6370265B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2009-05-08 | 2009-11-07 | 2010-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2013-05-08 | 2013-11-07 | 2014-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2017-05-08 | 2017-11-07 | 2018-05-09 | $7700.00 | Window Closed / Lapsed |