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[ abstract | slides | experimental
results | paper ]
also in Journal of the Optical Society of America A (JOSA A):
"Color Constancy through Inverse-Intensity Chromaticity Space"
[JOSA-04]
Abstract:
Existing
color constancy methods cannot handle both uniform colored surfaces and
highly textured surfaces in a single integrated framework.
Statistics-based methods require many surface colors, and become error
prone when there are only few surface colors. In contrast,
dichromatic-based methods can successfully handle uniformly colored
surfaces, but cannot be applied to highly textured surfaces since they
require precise color segmentation. In this paper, we present a
single integrated method to estimate illumination chromaticity from
single/multi-colored surfaces. Unlike the existing dichromatic-based
methods, the proposed method requires only rough highlight regions,
without segmenting the colors inside them. We show that, by analyzing
highlights, a direct correlation between illumination chromaticity and
image chromaticity can be obtained. This correlation is clearly
described in ``inverse-intensity chromaticity space'', a new
two-dimensional space we introduce. In addition, by utilizing the Hough
transform and histogram analysis in this space, illumination
chromaticity can be estimated robustly, even for a highly textured
surface. Experimental results on real images show the effectiveness of
the method.
Experimental
Results:
single-colored surface | multi-colored surface | highly
textured surface | complex scene
"Do not use the images in this website for testing your
code.
The images are compressed images whose brightness might
not be linear to the flux of incoming light.”
1.
Uniformly Colored Surfaces:
(a). Head model illuminated by a halogen lamp:
Estimation results: Er = 0.3779, Eg = 0.3242, Eb = 0.2866
White Reference: Er = 0.3710, Eg = 0.31855, Eb = 0.31031
(b) Head model illuminated by incandescent lamps:
Estimation results: Er = 0.4613, Eg = 0.3158, Eb = 0.2084
White Reference: Er = 0.502146, Eg = 0.29838, Eb =
0.19946
(c). Green sandal illuminated by a solux halogen
covered by green filter:
Estimation results: Er = 0.3067, Eg = 0.4546, Eb =
0.2404
White Reference: Er = 0.29804, Eg = 0.45807, Eb =
0.24387
(d). Green sandal illuminated by a solux halogen covered
by purple filter
Estimation results: Er = 0.3336, Eg = 0.0584, Eb =
0.5797
White Reference: Er = 0.3336, Eg = 0.06483, Eb =
0.601529
2. Multicolored Surface:
(a). Toy illuminated by incandescent lamps:
Estimation results: Er = 0.5304, Eg = 0.2817, Eb =
0.2262
White Reference: Er = 0.502146, Eg = 0.29838, Eb =
0.19946
(b). Toy illuminated by a halogen lamp covered by
blue filter:
Estimation results: Er = 0.2841, Eg = 0.3160, Eb =
0.3817
White Reference: Er = 0.26335, Eg = 0.2986, Eb =
0.43801
(c). Toy
illuminated by a halogen lamp covered by green filter:
Estimation results: Er = 0.3194, Eg = 0.4387, Eb = 0.2125
White Reference: Er = 0.29804, Eg = 0.45807, Eb =
0.24387
3. Highly textured surface:
(a). Fish illuminated by an incandescent lamp:
Estimation results: Er = 0.5068, Eg = 0.3112, Eb =
0.1946
White Reference: Er = 0.502146, Eg = 0.29838, Eb =
0.19946
(b). Fish illuminated by a halogen covered by blue
filter:
Estimation results: Er = 0.2398, Eg = 0.3144, Eb =
0.4378
White Reference: Er = 0.26335, Eg = 0.2986, Eb =
0.43801
(c). Magazine illuminated by fluorescent lamp
covered by green filter:
Estimation result: Er=0.2969, Eg=0.4877, Eb=0.2299
White reference: Er=0.2828, Eg=0.48119, Eb=0.2359
(d). Magazine illuminated by a halogen covererd by
blue filter:
Estimation results: Er = 0.2440, Eg = 0.3448, Eb =
0.4313
White Reference: Er = 0.26335, Eg = 0.2986, Eb =
0.43801
(d). Magazine illuminated by a halogen:
Estimation results: Er = 0.3368, Eg = 0.3285, Eb = 0.3410
White Reference: Er = 0.3710, Eg = 0.31855, Eb =
0.31031
(e) Complex scene illuminated by fluorescent light in uncontrolled
environment
Estimation results: Er = 0.3210, Eg = 0.3465, Eb = 0.3093
White Reference: Er = 0.33692, Eg = 0.34071, Eb =
0.31236
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