In this research, we proposed a new image quality evaluation index Color Distribution Index (CDI). It considers color gamut, contrast ratio, maximum luminance, electro-optical characteristics such as gamma, bit depth and JND as human visual system to evaluate the ability for reproducing visually smooth gradation. When the CDI cell was defined, we verified JND from fundamental matter such as JND in luminance and chromaticity using the latest TV sets. According to our investigations, luminance JND was ΔL/L=0.01, chromaticity JND was Δu'v'=0.001. We used these values for a unit CDI cell and evaluated bit depth needed for high image quality without any visible false contour. We clarified 12 bit is needed as necessary and sufficient condition to reproduce high image quality with latest LCD TV set designed based on BT.709. And we clarified that maximum luminance, contrast ratio, gamma characteristics and bit depth should be balanced to achieve TV sets of high image quality from the viewpoint of the total image quality improvement.
Toshiyuki Fujine, Takashi Kanda, Yasuhiro Yoshida, Michiyuki Sugino, Masatsugu Teragawa, Yoichi Yamamoto, Noboru Ohta, "Color Distribution Index (CDI) for Evaluating the Display Image Quality" in Proc. IS&T 16th Color and Imaging Conf., 2008, pp 152 - 157, https://doi.org/10.2352/CIC.2008.16.1.art00030