Lightness prediction of mirror display by amending CIECAM02 to include specular reflection.

This paper investigates if the color appearance model accurately predicts the lightness of a display whose surface features specular reflection such as a mirror display. Eight observers participate in psychophysical experiments and the results are compared with model prediction value. It is found that the model overestimates the lightness under the average surround condition where there is an intense specular reflection on the display surface. Based on the measurement results, we figured out that the conventional measurement method cannot measure practical specular reflection value. Thus we propose a new measurement method and modify the background parameter to include the specular reflection value. The proposed CIECAM02 considering specular reflection improves the coefficient of variation (CV) value under average surround condition from 20.56 to 12.40 while maintaining CVs under dim and dark surround conditions. In conclusion, we found that people perceive the specular reflection image as a background.

Compensation of color breaking in bi-focal depth-switchable integral floating augmented reality display with a geometrical phase lens.

A bi-focal integral floating system using a geometrical phase (GP) lens can provide switchable integrated spaces with enhanced three-dimensional (3D) augmented reality (AR) depth expression. However, due to the chromatic aberration properties of the GP lens implemented for the switchable depth-floating 3D images, the floated 3D AR images with the red/green/blue (R/G/B) colors are formed at different depth locations with different magnification effects, which causes color breaking. In this paper, we propose a novel technique to resolve the color breaking problem by integrating the R/G/B elemental images with compensated depths and sizes along with experiments to demonstrate the improved results. When we evaluated the color differences of the floated 3D AR images based on CIEDE2000, the experimental results of the depth-switchable integral floating 3D AR images showed that the color accuracies were greatly improved after applying a pre-compensation scheme to the R/G/B sub-images in both concave and convex lens operation modes of the bi-focal switching GP floating lens.

Classification of Iris Colors and Patterns in Koreans.

OBJECTIVES: The iris is the part of the eye that is colored, and it is an important feature in making an artificial eye. To address the lack of information about the brown Korean irises, we classified the colors and patterns of the irises of 100 Korean eyes. METHODS: The iris colors were extracted from 100 different digital photographs of each eye using K-mean clustering image analysis. The RGB data of the extracted colors were converted to CIELAB color space data and analyzed to determine the representative color of the iris in each photograph. The color differences were calculated to form groups of similar colors by matching the 100 samples into several groups with minimum color differences among them. The average hue value for each group was calculated, and the corresponding representative color was selected from 2 to 3 colors in one group. RESULTS: The iris colors were classified into seven brown color groups with 2 to 3 colors in each group. The coloration of Koreans' eyes appears to vary in a similar hue with differences in chroma and lightness. In addition, the iris patterns were classified into three basic patterns, namely, crown, sunshine, and flower, as well as three complex patterns that are mixtures of two basic patterns. CONCLUSIONS: We classified Korean iris colors and patterns for application in the design of artificial eyes.