Sophie Wuerger

Sophie Wuerger

Sophie Wuerger received her Ph.D. in Experimental Psychology at New York University (1991). Since then she has worked on visual perception, in particular colour vision, and is currently at the Centre of Cognitive Neuroscience, School of Psychology, University of Liverpool. She is a member of the Colour Group UK and the Optical Society of America. 


IS&T's Third European Conference on Colour in Graphics, Imaging and Vision (CGIV): Colour Appearance and Cone Signals: How does the Human Brain Combine the Retinal Cone Signals to Yield Colour Sensations such as Red, Green, Yellow and Blue?

What computation does the human brain perform when we experience "red" (or green, or yellow, or blue)? How does the human visual system combine the retinal cone signals (L, M, S cones) to yield these colour sensations?

To address this question we ask observers to select the colour which appears "neither red nor green" (yielding unique yellow and unique blue) or "neither yellow nor blue" (yielding unique red and unique green). Since we obtain these unique hue settings at different luminance and saturation levels, we have many points in 3-dimensional (LMS) cone space that correspond to a particular hue. This allows us to determine quantitatively how the cone signals are related to a particular perceived hue. Our results show that the human brain combines the (L,M,S) cone signals linearly when we experience these unique hues. Furthermore, the variability between observers is relatively small when expressed in terms of perceptual errors. Our results add further weight to the idea that the colour vision system in adult humans is able to recalibrate itself based on prior visual experience and that our colour appearance mechanisms may be a consequence of environmental constraints.



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