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US7068841B2 Expired / Lapsed US ⏱️ 0.0 years remaining

Automatic digital image enhancement

Assignee: Hewlett Packard Development Co LP
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Filing: 2001-06-29
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Granted: 2006-06-27
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Expires: 2021-06-29
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Abstract

Abstract A method and apparatus for enhancing a digital image. First, human faces are located within a digital image. The digital image is then analyzed, including analysis of the regions determined to be human faces and the analysis of the digital image as a whole. A tone mapping function is then determined for enhancing the image quality of the digital image. The tone mapping function is determined using both the analysis of detected faces and the analysis of the image as a whole to obtain a tone mapping function that incorporates both psychological factors (e.g., average face region lightness and average picture lightness) and signal factors (e.g., digital resolution, face region contrast, histogram uniformity, and noise issue). The tone mapping function is then applied to the digital image so as to produce an enhanced digital image. The present invention is automatic and does not require that the user provide any input. In addition, because the method and apparatus of the present invention incorporates both psychological factors and signal factors, the resulting enhanced images are perceived to be of good image quality.

Inventors

  • 👤 Huitao Luo

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 12:25
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/90; G06T5/40; G06T2207/00; G06T2207/30; G06T2207/30196; G06T2207/30201

Claims Analysis

Total Claims: 24
Claim 1
Independent Claim 200 words
A method for enhancing image quality of an original digital image having initial image quality issues comprising the steps of: a) locating human faces within said original digital image having initial image quality issues, said original digital image captured during a picture capture stage by a digital camera; b) analyzing said digital image, said analysis including analysis of said human faces located in step a) and including analysis of said digital image as a whole; c) utilizing said analysis of said faces located in step a) and using said analysis of said image as a whole to determine a tone mapping function for enhancing the image quality of said original digital image, said tone mapping function utilizing optimal ranges combined in a system energy formulation, wherein said tone mapping function combines both psychological factors and signal factors in said system energy formulation; and d) applying said tone mapping function determined in step c) to said digital image so as to produce an enhanced digital image different from said original digital image, wherein a mapped deviation of the human face region of the enhanced digital image is greater than the deviation of the human face region of the original digital image.
Claim 2
Independent Claim 200 words
A method for enhancing image quality of an original digital image having initial image quality issues comprising the steps of: a) locating human faces within said original digital image having initial image quality issues, said original digital image captured during a picture capture stage by a digital camera; b) analyzing said digital image, said analysis including analysis of said human faces located in step a) and including analysis of said digital image as a whole; c) utilizing said analysis of said faces located in step a) and using said analysis of said image as a whole to determine a tone mapping function for enhancing the image quality of said original digital image, said tone mapping function utilizing optimal ranges combined in a system energy formulation, wherein said tone mapping function combines both psychological factors and signal factors in said system energy formulation; and d) applying said tone mapping function determined in step c) to said digital image so as to produce an enhanced digital image different from said original digital image, wherein a mapped deviation of the human face region of the enhanced digital image is greater than the deviation of the human face region of the original digital image.
Claim 3
Dependent Claim 18 words
The method of claim 1 wherein steps a) through d) are performed automatically and without any user input.
Claim 4
Dependent Claim 27 words
The method of claim 1 wherein step a) further comprises: a1) applying a face detection algorithm to said digital image for locating faces within said digital images.
Claim 5
Dependent Claim 20 words
The method as recited in claim 1 wherein said psychological factors include average face region lightness and average picture lightness.
Claim 6
Dependent Claim 18 words
The method as recited in claim 1 wherein said signal factors include digital resolution and face region contrast.
Claim 7
Dependent Claim 16 words
The method as recited in claim 5 wherein said signal factors include histogram uniformity and noise.
Claim 8
Dependent Claim 20 words
The method as recited in claim 1 further comprising: generating a look-up table that corresponds to a tone mapping curve.
Claim 9
Dependent Claim 42 words
The method as recited in claim 7 further comprising: applying the tone properties within said lookup table to said digital image so as to alter the tone values of said digital image, thereby producing an enhanced digital image having altered tone values.
Claim 10
Dependent Claim 47 words
The method as described in claim 1 further comprising the steps of: d1) converting said digital image from an original format into a L*a*b* format prior to performing step a); and d2) converting said digital image back into said original format after step d) has been performed.
Claim 11
Dependent Claim 217 words
In a computer system including a processor coupled to a bus, and a memory unit coupled to the bus for storig information, a computer-implemented method for enhancing image quality of an original digital image having initial image quality issues comprising the steps of: a) locating human faces within said original digital image having initial image quality issues, said original digital image captured during a picture capture stage by a digital camera; b) analyzing said digital image, said analysis including analysis of said human faces located in step a) and including analysis of said digital image as a whole; c) utilizing said analysis of said faces located in step a) and using said analysis of said image as a whole to determine a tone mapping function for enhancing the image quality of said original digital image, said tone mapping function utilizing optimal ranges-combined in a system energy formulation wherein said tone mapping function combines both psychological factors and signal factors; and d) applying said tone mapping function determined in step c) to said digital image so as to produce an enhanced digital image different from said original digital image, wherein a mapped deviation of the human face region of the enhanced digital image is greater than the deviation of the human face region of the original digital image.
Claim 12
Dependent Claim 217 words
In a computer system including a processor coupled to a bus, and a memory unit coupled to the bus for storig information, a computer-implemented method for enhancing image quality of an original digital image having initial image quality issues comprising the steps of: a) locating human faces within said original digital image having initial image quality issues, said original digital image captured during a picture capture stage by a digital camera; b) analyzing said digital image, said analysis including analysis of said human faces located in step a) and including analysis of said digital image as a whole; c) utilizing said analysis of said faces located in step a) and using said analysis of said image as a whole to determine a tone mapping function for enhancing the image quality of said original digital image, said tone mapping function utilizing optimal ranges-combined in a system energy formulation wherein said tone mapping function combines both psychological factors and signal factors; and d) applying said tone mapping function determined in step c) to said digital image so as to produce an enhanced digital image different from said original digital image, wherein a mapped deviation of the human face region of the enhanced digital image is greater than the deviation of the human face region of the original digital image.
Claim 13
Dependent Claim 18 words
The method of claim 10 wherein steps a) through d) are performed automatically and without any user input.
Claim 14
Dependent Claim 27 words
The method of claim 11 wherein step a) further comprises: a1) applying a face detection algorithm to said digital image for locating faces within said digital images.
Claim 15
Dependent Claim 20 words
The method as recited in claim 10 wherein said psychological factors include average face region lightness and average picture lightness.
Claim 16
Dependent Claim 18 words
The method as recited in claim 10 wherein said signal factors include digital resolution and face region contrast.
Claim 17
Dependent Claim 16 words
The method as recited in claim 14 wherein said signal factors include histogram uniformity and noise.
Claim 18
Dependent Claim 213 words
A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method for enhancing image quality of an original digital image having initial image quality issues comprising the steps of: a) locating human faces within said original digital image having initial image quality issues, said original digital image captured during a picture capture stage by a digital camera; b) analyzing said digital image, said analysis including analysis of said human faces located in step a) and including analysis of said digital image as a whole; c) utilizing said analysis of said faces located in step a) and using said analysis of said image as a whole to determine a tone mapping function for enhancing the image quality of said original digital image, said tone mapping function utilizing optimal ranges combined in a system energy formulation wherein said tone mapping function combines both psychological factors and signal factors; and d) applying said tone mapping function determined in step c) to said digital image so as to produce an enhanced digital image different from said original digital image, wherein a mapped deviation of the human face region of the enhanced digital image is greater than the deviation of the human face region of the original digital image.
Claim 19
Dependent Claim 213 words
A computer readable storage medium storing instructions that, when executed by a computer, cause the computer to perform a method for enhancing image quality of an original digital image having initial image quality issues comprising the steps of: a) locating human faces within said original digital image having initial image quality issues, said original digital image captured during a picture capture stage by a digital camera; b) analyzing said digital image, said analysis including analysis of said human faces located in step a) and including analysis of said digital image as a whole; c) utilizing said analysis of said faces located in step a) and using said analysis of said image as a whole to determine a tone mapping function for enhancing the image quality of said original digital image, said tone mapping function utilizing optimal ranges combined in a system energy formulation wherein said tone mapping function combines both psychological factors and signal factors; and d) applying said tone mapping function determined in step c) to said digital image so as to produce an enhanced digital image different from said original digital image, wherein a mapped deviation of the human face region of the enhanced digital image is greater than the deviation of the human face region of the original digital image.
Claim 20
Dependent Claim 20 words
The computer-readable storage medium of claim 16 wherein steps a) through d) are performed automatically and without any user input.
Claim 21
Dependent Claim 20 words
The method as recited in claim 16 wherein said psychological factors include average face region lightness and average picture lightness.
Claim 22
Dependent Claim 20 words
The method as recited in claim 18 wherein said signal factors include digital resolution, face region contrast and histogram uniformity.
Claim 23
Dependent Claim 20 words
The method as recited in claim 16 further comprising: generating a look-up table that corresponds to a tone mapping curve.
Claim 24
Dependent Claim 45 words
The method as recited in claim 20 wherein step d) further comprises applying the tone properties within said lookup table to said digital image so as to alter the tone values of said digital image, thereby producing an enhanced digital image having altered tone values.

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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) 2009-06-26 2009-12-26 2010-06-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2013-06-26 2013-12-26 2014-06-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2017-06-26 2017-12-26 2018-06-27 $7700.00 Window Closed / Lapsed

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