The visibility of images displayed on mobile devices can significantly vary according to the lighting conditions. Generally, increasing the lighting scale produces a more compressed perceived color gamut. In addition, the compression rate of the perceived color gamut varies according to the hue angle. Therefore, this paper presents a method of compensating the luminance and chrominance according to the hue of the image displayed on a mobile device. Two psychophysics experiments are initially performed to analyze the human perception of luminance and chrominance. The perceived luminance and perceived chrominance reduction rates are then calculated for the primary colors. Next, to calculate the perceived luminance and chrominance reduction rates for all hue angles, piecewise linear interpolation is used between each primary color hue angle. Finally, the luminance and chrominance compensation rates are calculated by using the precalculated perceived luminance and chrominance reduction rates. The luminance and chrominance compensation rates according to the hue angle are then applied to an input image. Experimental results show that the proposed method enhances the colors in indoor and outdoor environments.
['D. Kim', 'Ji-Hoon Yoo', 'Won-Hee Choe', 'Yeong-Ho Ha']
Visibility Enhancement of Mobile Device Through Luminance and Chrominance Compensation Upon Hue