Simulation of appearance of objects in low illuminance

Research Project

Project/Area Number	04650034
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	物理計測・光学
Research Institution	Chiba University
Principal Investigator	YAGUCHI Hirohisa Chiba University, Department of Engineering, Associate Professor, 工学部, 助教授 (30134844)
Co-Investigator(Kenkyū-buntansha)	SHIOIRI Satoshi Chiba University, Department of Engineering, Research Associate, 工学部, 助手 (70226091) HANEISHI Hideaki Chiba University, Department of Engineering, Research Associate, 工学部, 助手 (20228521) MIYAKE Yoichi Chiba University, Department of Engineering, Professor, 工学部, 教授 (70027895)
Project Period (FY)	1992 – 1993
Project Status	Completed (Fiscal Year 1993)
Budget Amount *help	¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Keywords	color appearance / mesopic vision / color matching / color reproduction / colorimetry / 測色値 / 桿体 / 明視視
Research Abstract	Color vision at an intermediate luminance or illuminance level between photopic and scotopic range is called mesopic vision. In mesopic vision, we perceive different colors from in photopic vision, because not only ones but also rods contribute to the visual response. In this research report, color appearance for 36 color chips under 6 illuminance levels from 0.01 lx to 1000 lx was estimated by a haploscopic color matching method. A test color chip was presented in the test field and observed by the left eye, and the Natural Color System (NCS) Color Atlas in the reference field was observed by the right eye. One color chip which was the same color appearance as the test color was selected from the NCS Color Atlas. Subjects responded four scales of the NCS, hue, whiteness, blackness and chromaticness. The experimental results show that as the illuminance decreased, (1) chromaticness decreased, (2) hue shift was observed in green-blue and yellow-orange regions and (3) brightness contrast decreased. Using obtained experimental results, we have developed an algorithm which can predict color appearance for mesopic vision from color images taken by a still video camera in the photopic condition.