US6839088B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for estimating physical properties of objects and illuminants in a scene using modulated light emission
Assignee: Leland Stanford Junior University
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Filing: 2001-06-04
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Granted: 2005-01-04
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Expires: 2021-06-04
Abstract
Abstract Color balancing algorithms for digital image processing require an accurate estimate of the physical properties of the ambient scene illuminant, particularly its spectral power distribution. An active imaging method and apparatus estimate these properties by emitting modulated light with a known spectral power distribution into a region of a scene. Backscattered light is detected and demodulated to separate output representing active emitter light from output representing ambient illuminant light. Using the emitter-related detector output and the known emitter spectral power distribution, the surface spectral reflectance function of the illuminated scene region can be computed. Subsequently, the spectral power distribution of the ambient scene illuminant can be computed from the surface reflectance function and the illuminant-related output of the detector. The estimated spectral power distribution can be used in standard color balancing algorithms for digital or film images.
Inventors
- 👤 Jeffrey M. Dicarlo
- 👤 Peter B. Catrysse
- 👤 Feng Xiao
- 👤 Brian A. Wandell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:19
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/55; G06; G06T; G06T7/00; G06T7/90; G06V; G06V10/00; G06V10/10; G06V10/12; G06V10/14; G06V10/143; G06V10/145; G06V10/40; G06V10/60; H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6083; H04N23/00; H04N23/80; H04N23/84; H04N23/88; G06T2207/00; G06T2207/10; G06T2207/10016; G06T2207/10024; G06T2207/10141; G06T2207/10152
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
106 words
A method for estimating physical properties of a scene comprising a scene object illuminated by a scene illuminant, said method comprising: a) illuminating said scene with modulated light from an emitter, said modulated light having a predetermined spectral power distribution; b) detecting backscattered light from said scene using a detector; c) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and d) estimating physical properties of said scene object in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 2
Independent Claim
106 words
A method for estimating physical properties of a scene comprising a scene object illuminated by a scene illuminant, said method comprising: a) illuminating said scene with modulated light from an emitter, said modulated light having a predetermined spectral power distribution; b) detecting backscattered light from said scene using a detector; c) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and d) estimating physical properties of said scene object in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 3
Dependent Claim
25 words
The method of claim 1 wherein said physical properties of said scene object are related to a spectral surface reflectance function of said scene object.
Claim 4
Dependent Claim
25 words
The method of claim 1 , further comprising estimating physical properties of said scene illuminant in dependence upon said physical properties of said scene object.
Claim 5
Dependent Claim
24 words
The method of claim 3 wherein said physical properties of said scene illuminant are related to a spectral power distribution of said scene illuminant.
Claim 6
Dependent Claim
28 words
The method of claim 1 , further comprising performing color balancing on an image of said scene based in part on analysis of said output from said detector.
Claim 7
Dependent Claim
13 words
The method of claim 1 wherein said modulated light is temporally modulated light.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein said modulated light is spatially modulated light.
Claim 9
Independent Claim
106 words
A method for estimating physical properties of a scene comprising a scene object illuminated by a scene illuminant, said method comprising: a) illuminating said scene with modulated light from an emitter, said modulated light having a predetermined spectral power distribution; b) detecting backscattered light from said scene using a detector; c) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and d) estimating physical properties of said scene illuminant in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 10
Independent Claim
106 words
A method for estimating physical properties of a scene comprising a scene object illuminated by a scene illuminant, said method comprising: a) illuminating said scene with modulated light from an emitter, said modulated light having a predetermined spectral power distribution; b) detecting backscattered light from said scene using a detector; c) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and d) estimating physical properties of said scene illuminant in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 11
Dependent Claim
24 words
The method of claim 8 wherein said physical properties of said scene illuminant are related to a spectral power distribution of said scene illuminant.
Claim 12
Dependent Claim
28 words
The method of claim 8 , further comprising performing color balancing on an image of said scene based in part on said physical properties of said scene illuminant.
Claim 13
Dependent Claim
13 words
The method of claim 8 wherein said modulated light is temporally modulated light.
Claim 14
Dependent Claim
13 words
The method of claim 8 wherein said modulated light is spatially modulated light.
Claim 15
Independent Claim
104 words
An apparatus for detecting light in a scene comprising a scene object illuminated by a scene illuminant, said apparatus comprising: a) an emitter for emitting modulated light having a predetermined spectral power distribution; b) a detector for detecting backscattered light from said scene; and c) processing means for: i) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and ii) estimating physical properties of said scene object in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 16
Independent Claim
104 words
An apparatus for detecting light in a scene comprising a scene object illuminated by a scene illuminant, said apparatus comprising: a) an emitter for emitting modulated light having a predetermined spectral power distribution; b) a detector for detecting backscattered light from said scene; and c) processing means for: i) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and ii) estimating physical properties of said scene object in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 17
Dependent Claim
25 words
The apparatus of claim 13 wherein said physical properties of said scene object are related to a spectral surface reflectance function of said scene object.
Claim 18
Dependent Claim
28 words
The apparatus of claim 13 , further comprising processing means for estimating physical properties of said scene illuminant in dependence upon said physical properties of said scene object.
Claim 19
Dependent Claim
24 words
The apparatus of claim 15 wherein said physical properties of said scene illuminant are related to a spectral power distribution of said scene illuminant.
Claim 20
Dependent Claim
31 words
The apparatus of claim 13 , further comprising processing means for performing color balancing on an image of said scene based in part on analysis of said output from said detector.
Claim 21
Dependent Claim
12 words
The apparatus of claim 13 wherein said emitter emits temporally modulated light.
Claim 22
Dependent Claim
12 words
The apparatus of claim 13 wherein said emitter emits spatially modulated light.
Claim 23
Dependent Claim
12 words
The apparatus of claim 13 wherein said apparatus is an imaging apparatus.
Claim 24
Dependent Claim
12 words
The apparatus of claim 13 wherein said apparatus is a light meter.
Claim 25
Independent Claim
104 words
An apparatus for detecting light in a scene comprising a scene object illuminated by a scene illuminant, said apparatus comprising: a) an emitter for emitting modulated light having a predetermined spectral power distribution; b) a detector for detecting backscattered light from said scene; and c) processing means for: i) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and ii) estimating physical properties of said scene illuminant in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 26
Independent Claim
104 words
An apparatus for detecting light in a scene comprising a scene object illuminated by a scene illuminant, said apparatus comprising: a) an emitter for emitting modulated light having a predetermined spectral power distribution; b) a detector for detecting backscattered light from said scene; and c) processing means for: i) analyzing output from said detector to distinguish between illuminant output and emitter output, wherein said illuminant output represents backscattered light from said scene illuminant, and said emitter output represents backscattered light from said emitter; and ii) estimating physical properties of said scene illuminant in dependence upon said emitter output and said predetermined spectral power distribution.
Claim 27
Dependent Claim
24 words
The apparatus of claim 22 wherein said physical properties of said scene illuminant are related to a spectral power distribution of said scene illuminant.
Claim 28
Dependent Claim
31 words
The apparatus of claim 22 , further comprising processing means for performing color balancing on an image of said scene based in part on said physical properties of said scene illuminant.
Claim 29
Dependent Claim
12 words
The apparatus of claim 22 wherein said emitter emits temporally modulated light.
Claim 30
Dependent Claim
12 words
The apparatus of claim 22 wherein said emitter emits spatially modulated light.
Claim 31
Dependent Claim
12 words
The apparatus of claim 22 wherein said apparatus is an imaging apparatus.
Claim 32
Dependent Claim
12 words
The apparatus of claim 22 wherein said apparatus is a light meter.
References Cited (Backward Citations)
US5081530A
Cited
US6081076A
Cited
US5548398A
Cited
US6122042A
Cited
US6069972A
Cited
US6777684B1
Cited
US6505002B2
Cited
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| 3.5 Years (Year 4) | 2008-01-04 | 2008-07-05 | 2009-01-04 | $2000.00 | Window Closed / Lapsed |
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