PNB Colloquium - Richard Murray - Seeing light and surfaces



Seeing light and surfaces

Richard Murray
Department of Psychology and Centre for Vision Research
York University

Lightness constancy is the remarkable ability of the human visual system to perceive shades of black, white, and grey surfaces accurately across a wide dynamic range of lighting conditions and contexts.  How the visual system accomplishes this is a fundamental and largely unsolved problem.  In this talk I will describe recent work in my lab on developing models of lightness perception.  I will show demonstrations illustrating that percepts of glow interact in interesting ways with percepts of three-dimensional shape.  I will describe novel reverse correlation experiments that use the argyle illusion, a strong but poorly understood lightness illusion, to test current computational models of lightness constancy.  Finally, I will present ongoing work that uses probabilistic methods from computer vision to develop a new Bayesian computational model of human lightness perception, that gives a good account of lightness illusions and phenomena that are problematic for current theories of lightness.

Richard Murray is a faculty member in the Department of Psychology and Centre for Vision Research at York University.  He received his Ph.D. at the University of Toronto with Patrick Bennett and Allison Sekuler.  He held a postdoctoral position with Wilson Geisler at the University of Texas at Austin, followed by a faculty position at the University of Pennsylvania before moving to York University.  His work centres on mathematical and computational models of visual perception, including visual decision making and lightness perception.

Host: Dan Goldreich

Location information

1280 Main St W, Hamilton, ON, Canada

Hamilton L8S
1280 Main Street West

Contact Department

Department of Psychology, Neuroscience & Behaviour (PNB)
Psychology Building (PC), Room 102
McMaster University
1280 Main Street West
Hamilton Ontario L8S 4K1