Image Statistics for Golden Appearance of a Painting by a Japanese Edo-era Artist Jakuchu Ito

摘要

Humans use color terms to categorize huge amount of colors in the real world. Previous researches have shown that 11 basic color terms are sufficient to represent colors in many languages but recently we have found that color terms gold and silver are frequently used for images of objects with high specular reflectances. However, there are objects that appear golden but do not have clear highlights. One example can be found in Roshohakuho-zu, a painting drawn by a Japanese artist Jakuchu Ito. To find image features generating the golden appearance of this painting, we conducted psychophysical experiments using image patches extracted from the painting. We found that correlation between colors and luminances is related to goldness ratings evaluated by human subjects and manipulation of the color-luminance correlation affects the goldness of images. These results suggest that humans make use of the color-luminance correlation to perceive golden appearance of images.