Ye Seul Baek

Monitor brightness changes under a wide range of surround conditions

Display brightness data were collected under a wide range of surround conditions. A 24 in. (60.96 cm) LCD display was used to generate color stimuli, and a 107 in. (271.78 cm) two-dimensional illuminator was used to generate various surround conditions. The brightness values of the display under 89 monitor-surround-luminance combinations were collected from 10 or 24 observers. The surround ratio, SR, i.e., the luminance ratio between the surround and the monitor, varied from 0 to 90. Based on the collected brightness data, we propose a new c value as the log function of the surround ratio, SR, to improve the performance of the CIECAM02 brightness predictor Q.

Preferred Memory Color Difference between the Deuteranomalous and Normal Color Vision

The goal of this study is to evaluate the difference of the preferred hues of familiar objects between the color deficient observer and the normal observer. Thirteen test color images were chosen covering fruit colors, natural scene and human faces. It contained red, yellow, green, blue, purple and skin color. Two color deficient observer (deuteranomal) and two normal observers were participated in this experiment. They controlled the YCC hue of the objects in the images to obtain the most preferred and the most natural image. The selected images were analyzed using CIELAB values of each pixel. Data analysis results showed that in the case of naturalness, both groups selected the similar hues for the most of image, while, in the case of preference, the color deficient observer preferred more reddish or more greenish images. Since the deuteranomalous observer has relatively week perception for red and green region, they may prefer more reddish or greenish color. The color difference between natural hue and preferred hue of deuteranomal observer is bigger than those of normal observer.