Fig 1.
System architecture for the proposed illuminant normalization method.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.
Fig 2.
Some examples of different illumination distributions.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.
Fig 3.
The main steps of the illuminant direction estimation method.
It should be noted that three of sixteen local regions are selected to calculate the final illuminant direction.
Fig 4.
Real illuminant directions and estimated illuminant directions.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.
Fig 5.
The three-dimensional and two-dimensional representations of Gaussian function used in MSRCR.
(a) No normalization. (b) Normalization.
Fig 6.
Central region’s coordinates of Gaussian and their corresponding values.
(a) Coordinate. (b) The distribution of conventional Gaussian’s values. (c) The real situation.
Fig 7.
The three-dimensional and two-dimensional representations of Gaussian function used in our method.
(a) 60°. (b) 120°. (c) −60°. (d) −120°.
Fig 8.
The schematic diagram for the rule of interception.
Fig 9.
Comparison among three different sizes of parameter t.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.
Fig 10.
Comparison of different illuminant normalization methods for gray face images from the Yale face database B.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.
Fig 11.
Comparison of different illuminant normalization methods for color face images from the CMU-PIE database.
Reprinted from http://www.ri.cmu.edu/research_project_detail.html?project_id=418&menu_id=261 under a CC BY license, with permission from Takeo Kanade, original copyright 2003.
Fig 12.
The analysis of feature point location.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.
Fig 13.
The location accuracies for different methods.
(a) Gray image. (b) Color image.
Fig 14.
Performance comparisons of different methods.
Fig 15.
Local shadow and false edge around the nose.
Reprinted from http://vision.ucsd.edu/~leekc/ExtYaleDatabase/ExtYaleB.html under a CC BY license, with permission from David Kriegman, original copyright 2001.