Abstract
All established measures for color constancy come with methodological problems or serious constraints. They rarely capture our everyday experience of the phenomena. Here we present a new and intuitive approach that allows us to measure constancy for arbitrary colors without multiple illuminants in the scene. Participants (N=17) were asked to bring a personal object (e.g. scarf) that had for them a well-defined colour that they were confident they could identify in absence of the object. Without the object being present, participants were asked to select from the Munsell Book of Color (Glossy Edition) the chip that best represented the colour of their chosen object. They performed the task first in a room under neutral daylight illumination and in two other rooms that had non-daylight illuminations provided by windows covered with filters. The task was performed twice in each room but always on different days. The filters induced substantial changes in the objects’ color coordinates by 24 (purple filter) and 28 (green filter) Lab units. Before selecting the chip, participants adapted to the illumination while performing a color sorting task. Under each of the three illuminations, we measured the Lab coordinates of the objects, the illumination and the selected chips. We also selected the chip that best matched the object in its presence. In this task, our participants were perfectly color constant. The change in the objects’ color coordinates under the illumination changes was equalled by the changes in the color coordinates of the chips selected under the different illuminants. On average, 99.2% (+/- 3.6% s.e.) constancy was achieved. There was no significant difference for the two filter conditions. Our results show that perfect color constancy can be achieved in a task and conditions that are highly representative of the uses of color constancy in everyday life.
Meeting abstract presented at VSS 2015