Preferred and maximally acceptable color gamut for reproducing natural image content

Abstract

With the development of wide-gamut display technology, the need is clear for understanding the required size and shape of color gamut from the viewers' perspective. To that end, experiments were conducted to explore color-gamut requirements based on viewers' preferred level of chroma enhancement of standard-gamut images. Chroma preferences were measured for multiple hues using single-hue images, and a corresponding hue-dependent preferred chroma enhancement was successfully applied to natural, multi-hue images. The multi-hue images showed overall success, though viewers indicated that reds could be decreased even further in colorfulness, and yellows could be increased, which may argue in favor of multi-primary displays. Viewer preferences do vary within the population, primarily in overall chroma level, and the differences can be largely accounted for with a single parameter for chroma-level adjustment that includes the preferred hue dependence. Image content dependencies were also found, but they remain too complex to model. The huedependent chroma preference results can be applied to display design and color-enhancement algorithms.

Subjective evaluation of natural high‐saturated images on a wide gamut display

“…This is because it supports the prediction that the viewer's preferences for more saturated images than a previously preferred one on the wide color gamut display would be high. Murdoch et al asked subjects to select the maximally acceptable levels of chroma using wide color‐gamut display and showed that these viewers were willing to accept chroma levels higher than the preferred levels. Our results suggest that the images in this fashion, that is, over previous preferred images, are not only acceptable but indeed have high preferences.…”

“…Previous studies on wide color gamut displays have mainly focused on the preferred chroma of natural images . For example, Murdoch et al investigated preferred levels of chroma using an RGB wide gamut display.…”

“…Earlier studies have reported conflicting results. For example, Murdoch et al also asked the subjects to select the maximally acceptable levels of chroma, showing that they were willing to accept chroma levels higher than the preferred levels. These results suggest that the preferences for more saturated images may still be high compared to a previously most preferred one.…”

“…Previous studies on wide color gamut displays have mainly focused on the preferred chroma of natural images. [2][3][4][5][6] For example, Murdoch et al 4 investigated preferred levels of chroma using an RGB wide gamut display. In the study, natural images with very narrow hue ranges were used, and subjects' task was to select the level of colorfulness that they preferred for each image by changing their CIELAB chroma values.…”

Preferred color gamut boundaries for wide‐gamut and multiprimary displays

“…As reported previously, we intentionally utilized image content biased toward the outer edges of the gamut area, thereby allowing the use of linear chroma expansion, and we avoided skintones altogether. 6 In the present article, we continue with both of these constraints. Figure 1 summarizes the results of our prior paper, showing three gamuts: the standard gamut of the starting image encoding, Rec.…”