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RESEARCH PROFILES

John Tsotsos

BASc; MSc; PhD (Toronto)

Computer Science and Engineering, Faculty of Science and Engineering

Director, Center for Vision Research and Canada Research Chair, Computational Vision and Professor

In 1980, Tsotsos founded the computer vision research group at the University of Toronto and soon afterwards the Technical Report series "Research in Biological and Computational Vision". In 1985, he was appointed a Fellow in the Artificial Intelligence and Robotics Program of the Canadian Institute for Advanced Research. In November of 1990, he was named the Canadian Pacific (Unitel) Fellow of the Canadian Institute for Advanced Research.  His two 5-year terms as CIAR Fellow recognized his work on the computational complexity of biological visual perception, the development of an accompanying theory of visual attention that makes strong predictions about the psychophysics and neurobiology of human and primate perception, and the practical application of this work in the development of PLAYBOT, a visually-guided robot to assist physically disabled children in play.

Tsotsos has also looked for ways to model human mechanisms of visual motion in machines. Integrating the fields of visual psychology, computer vision, robotics, and visual neuroscience, he is developing robotic wheelchairs for the disabled that can be controlled by vision. In 2006, Tsotsos and a team of researchers uncovered new evidence that the brain cleans up images for us by suppressing certain visual areas. The study, which used MEG (magnetoencephalography), a technique that measures changes in magnetic fields in the brain, showed that within fractions of a second, this target becomes surrounded by a suppressive zone in the visual cortex. This proves a theory first put forth by Tsotsos in 1990 called the “ST” or “selective tuning” model of visual attention. Previous experiments have demonstrated the theory measuring human’s visual behavior; this new set of experiments is the first to show neurophysiological changes in the brain for such images that are consistent with the theory. Scientists previously believed that the brain worked in a simple hierarchical manner, with the visual cortex giving preferential treatment to the most relevant visual task.