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Ana Radonjić, Nicolas P. Cottaris, David H. Brainard; Color constancy in a natural task is high. Journal of Vision 2014;14(10):798. doi: 10.1167/14.10.798.
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© ARVO (1962-2015); The Authors (2016-present)
Color constancy is often studied using adjustment procedures. In real life, however, we rarely adjust object colors. Rather, we use color to identify and choose objects. We studied constancy using a novel paradigm, adapted from the blocks-copying task of Ballard et al (2005). In our experiment, subjects were asked to complete a fairly natural task that required them to judge object color across an illumination change. At the beginning of each trial the subject saw three rendered scenes —the target, the source and the test— presented on a computer display. The target scene contained four colored blocks of different simulated reflectance. Their arrangement varied randomly on each trial. The source scene contained eight blocks: one pair of potential matches for each target block. The degree of similarity of each potential match to the target varied across trials. The test scene contained four identical dark gray blocks. The subjects' task was to replace the gray blocks with blocks chosen from the source, so as to recreate the arrangement in the target scene as closely as possible. In the illuminant-constant condition, all three scenes were rendered under the same illumination (D65). In the illuminant-changed condition, the simulated illuminations of the source and test were changed to 12000°K. Based on the subjects' choices, we inferred their perceptual matches for each target block in each condition via a variant of the maximum likelihood difference scaling method. Two main findings were consistent across our four subjects: (1) When the illumination was constant the distance between the target block and its choice-based match was small (2.2 - 3.9 ∆E), supporting the validity of our method. (2) When the illumination changed, the choice-based matches indicated good constancy (constancy indices 0.7 - 0.8). Our results show that color constancy is high when probed using a natural task.
Meeting abstract presented at VSS 2014
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