Abstract
Naturalness judgments in color rendering of complex scenes indicate that observers require illuminants with correlated color temperatures (CCT) around 7000K. Here we investigated the influence of the complexity and memory color on these judgments. Fifteen images of commercial food counters of fruits, vegetables, meat, and fish were digitalized by a hyperspectral system. The scenes were simulated as if they were rendered by illuminants synthesized from Judd’s daylight spectral basis functions for a grid of chromaticities on and around the Planckian locus with CCT ranging 2,222 – 20,000K and were displayed on an LCD monitor controlled by a ViSaGe system. The task of the observer was always to adjust the color of the illumination to produce the most natural appearance of the test object. In condition A, the test object was a part of an object selected from a scene. In condition B, the test object was the same but 70% the pixels were spatially randomized. To make sure that in A and B the observers recognized the test object the complete scene was shown to the observer beforehand each adjustment trial. Condition C was similar to B except that the observers did not see the full scene and therefore did not recognize the object. The background of the test object was always the average of the complex scene. One group of observers tested conditions A and B and a different group tested condition C. In A and B conditions the average CCT obtained was considerably lower than that obtained for the complex scenes: for A was 6100K and for B was 6500K. For condition C even lower CCT was obtained, about 5000K. These results show that both the complexity and the memory color of the objects have a considerable influence in the judgments of naturalness of the illumination.
Meeting abstract presented at VSS 2012