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Beyond scattering and absorption: Perceptual un-mixing of translucent liquids

Chadwick, A.C.; Cox, G.; Smithson, H.E.; Kentridge, R.W.

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A.C. Chadwick

G. Cox

H.E. Smithson


Is perception of translucence based on estimations of scattering and absorption of light or on statistical pseudocues associated with familiar materials? We compared perceptual performance with real and computer-generated stimuli. Real stimuli were glasses of milky tea. Milk predominantly scatters light and tea absorbs it, but since the tea absorbs less as the milk concentration increases, the effects of milkiness and strength on scattering and absorption are not independent. Conversely, computer-generated stimuli were glasses of “milky tea” in which absorption and scattering were independently manipulated. Observers judged tea concentrations regardless of milk concentrations, or vice versa. Maximum-likelihood conjoint measurement was used to estimate the contributions of each physical component—concentrations of milk and tea, or amounts of scattering and absorption—to perceived milkiness or tea strength. Separability of the two physical dimensions was better for real than for computer-generated teas, suggesting that interactions between scattering and absorption were correctly accounted for in perceptual unmixing, but unmixing was always imperfect. Since the real and rendered stimuli represent different physical processes and therefore differ in their image statistics, perceptual judgments with these stimuli allowed us to identify particular pseudocues (presumably learned with real stimuli) that explain judgments with both stimulus sets.


Chadwick, A., Cox, G., Smithson, H., & Kentridge, R. (2018). Beyond scattering and absorption: Perceptual un-mixing of translucent liquids. Journal of Vision, 18(11), 1-15.

Journal Article Type Article
Acceptance Date Jul 9, 2018
Online Publication Date Oct 29, 2018
Publication Date Oct 1, 2018
Deposit Date Sep 6, 2018
Publicly Available Date Nov 8, 2018
Journal Journal of Vision
Publisher Association for Research in Vision and Ophthalmology
Peer Reviewed Peer Reviewed
Volume 18
Issue 11
Pages 1-15


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