Unique hue judgments using saturated and desaturated Munsell samples under different light sources

Abstract

Past studies investigating the unique hues only used samples with a relatively high saturation levels under standard illuminants. In this study, 10 observers selected the four samples with unique hues from 40 V6C8 (Value 6 Chroma 8) and 40 V8C4 (Value 8 Chroma 4) Munsell samples under six light sources, comprising three levels of Duv (i.e., 0, −0.02, and −0.04) and two levels of correlated color temperature (i.e., 2700 and 3500 K). Significant differences were found between the two chroma levels for unique blue and yellow, with the hue angles of unique yellow and blue judged using the desaturated samples being significantly different from those defined in CIECAM02. The iso‐lines of unique yellow, blue, and green did not always go through the origin of the a*‐b* or a′‐b′ planes in CIELAB and CAM02‐UCS. Thus, the problems of CIECAM02, CIELAB, and CAM02‐UCS identified in this study need further investigations.

Investigating unique hues at different chroma levels with a smaller hue angle step

“…Table 2 summarizes the intra-and inter-observer variations for each unique hue at each chroma level under each adapting condition. It can be observed that higher chroma levels resulted in smaller intraand inter-observer variations under all the three adapting conditions, which was similar to past studies [19,20]. Both the intra-and interobserver variations, especially to those at the chroma level of 10, were a little larger than those in the past work using Munsell samples [19,20].…”

“…It can be observed that higher chroma levels resulted in smaller intraand inter-observer variations under all the three adapting conditions, which was similar to past studies [19,20]. Both the intra-and interobserver variations, especially to those at the chroma level of 10, were a little larger than those in the past work using Munsell samples [19,20]. The comparable inter-and intra-observer variations, however, were not found in past studies [7,8,16,17,19,20,22].…”

“…Both the intra-and interobserver variations, especially to those at the chroma level of 10, were a little larger than those in the past work using Munsell samples [19,20]. The comparable inter-and intra-observer variations, however, were not found in past studies [7,8,16,17,19,20,22].…”

“…It was found that the hue angles of the unique hues were significantly different between the two chroma levels, suggesting that CIECAM02 had a bad hue uniformity. In addition, the hue angles of unique blue and yellow in CIECAM02 were significantly different from the experiment results [19]. Shamey et al then performed a similar experiment under four lighting conditions using the two sets of 40 Munsell samples.…”

“…Studies have been carried out to investigate whether these defined hue angles in different color appearance models and uniform color spaces correlate to human perception under different viewing conditions. The reader is referred to two review articles, which were published in 2004 [5] and 2014 [15], and the references for the six new studies since 2014 [16][17][18][19][20][21]. In these studies, a series of color stimuli, with the same chroma and lightness levels but different hues, were presented to human observers and the observers were instructed to select the ones that appeared to have the four unique hues.…”