NPR 이미지의 색 항상성 - 애니메이션 장면을 중심으로

Abstract

Animation is a video made up of non-photorealistic expressive still images considering the human perspective. There is an increasing need to clarify the color expression characteristics of NPR images to facilitate the animation production. This study paid attention to the color constancy, which recognizes the color of the surface as the same color even when the lighting color of the environment changes to various colors. Therefore, the color constancy was researched in NPR animation images. The subjects produced animation images including the character and the background, considering the color composition including 6 objects (apple, banana, leaf, soil, tree, skin) based on the basic color term. According to the change of time, the colors were set to 12:00 PM (6500K) at noon, 6:00 PM (4000K) at sunset, and 12:00 PM (20000K) at night. As a result, the CIE LAB values of the object color shown in the NPR animation image were obtained, and the Color Constancy Index (CI) was calculated according to the color temperature change to confirm the effect of color constancy. As a result, the CI of all object colors except for the sky at 4000K was higher than 0.6, confirming the effect of the color constancy. In addition, at 20000K, lower than CI=0.5 was obtained for all objects except for the skin, confirming the action of the low color constancy. This study is different from the existing color constancy studies focusing on photographed images, and it can help to build a color database required from the viewpoint of animation creators.