Correcting veiling glare of refined CIECAM02 for mobile display

Abstract

Small displays are widely used; they are small enough to be carried around and are often viewed under extreme surround conditions. Under bright illumination, mobile display users experience “veiling glare” caused by bright ambient lighting. A refined version of CIECAM02 called “Refined CIECAM02 and original CIECAM02” were tested to predict visual results in terms of lightness (J), colourfulness (M), and brightness (Q) on a 2-inch sized display (2″) mobile phone under four surround conditions; dark (0 cd/m2), dim (5 cd/m2), average (1000 cd/m2), and bright (10,000 cd/m2). Other than the two versions of CIECAM02 using the original data, a correction to the models' predicted lightness J and a black correction to the original data were developed. Overall, the refined CIECAM02 plus the J correction performed the best for predicting the lightness, brightness and colourfulness under all the viewing conditions, especially for bright surround condition. Furthermore, another experiment was carried out using complex images to verify different versions of CIECAM02. The images were reproduced using JMh (lightness, colourfulness, and hue) spaces from the modified CIECAM02 versions. The experiment was conducted by comparing original images viewed under dim, average, or bright surround conditions and the predicted images were viewed under dark surround condition on two identical mobile displays. The different versions of the CIECAM02 showed similar results to each other for dim and average surround conditions but large differences when predicting the images under bright surround condition. The refined CIECAM02 with the J′ formula performed the best amongst all four CIECAM02 versions. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2013.