Dr. Bart Farell
Associate Professor, Dept. of Biomedical &
Ph.D., McGill University, 1977
Human vision and cognition.
Light falling on the two-dimensional retina comes to elicit a world of objects in three-dimensional space. I study the mechanisms that the human visual system uses to construct these objects of perception and cognition. Current and recent research is directed toward understanding the mechanisms of binocular vision and stereoscopic depth perception, determining the computations behind the perceived motion of objects in complex environments, exploring the brain's coding of color information, and demarcating the limits of attention. The methods I use are those of psychophysics, which aim to uncover the functional mechanisms of vision by measuring how task performance varies with the properties of the stimulus and the state of the observer.
At the current time, members of the lab are concentrating on stereopsis: the ability to combine information from the two eyes and recover depth from the subtle differences in their retinal images. Traditional theories, dating back to the 1830's, suppose that each eye's image is analyzed to the point where complex image features are identified before the visual system compares the information in the two eyes and extracts positional disparities. Our evidence disputes this view; we think that stereo matching occurs early, uses relatively unanalyzed stimulus elements, and guides the identification of objects and their spatial layout. We are attempting to identify these stimulus elements and to model the computation that converts retinal disparities into depth.
In addition to enlarging our understanding of the brain's functional organization, the work has implications for physiological investigations of neuronal pathways, computational investigations of neural and decision processes, clinical investigations of visual disorders and trauma, and applied investigations of vehicle safety and visual devices and interfaces.
Publications and Abstracts:
For a list of publications, please click here