Grant: Research Tools and Instruments - Category 1 (<$150,000)

Stereopsis is the ability to use the differences between the two eyes' view of the world to estimate relative depth. It is well established that under ideal conditions the human visual system is exquisitely sensitive to this information, thresholds as small as 10 arc sec are not uncommon. Less often recognized advantages provided by stereopsis are the sense of the volume of an object, perception of extended surfaces and localization of object boundaries. These features of stereoscopic processing make it an ideal basis for segmenting objects from their background, or from one another. The vast majority of research in human stereopsis has been conducted using simple line or random dot stimuli presented on an electronic display. Apart from notable exceptions (Buckley & Frisby 1993, Frisby & Buckley 1995, Allison & Gillam 2009, McKee & Taylor 2010) even when physical targets have been used, they have been designed to avoid the presence of additional depth cues or contextual information (for instance Ogle 1953 used needles). While such experiments have made important inroads in our understanding of the fundamental mechanisms of human stereopsis, they are not necessarily directly applicable to how stereopsis is employed when viewing real objects which contain multiple sources of depth information. The equipment requested here is a purpose-built apparatus designed to permit precise assessment of human depth perception of real objects under carefully controlled viewing conditions. The results will be applicable to both the advancement of our basic science program, and will inform ongoing research into 3D media. As the only one of its type in Canada, this apparatus will permit significant advances in the study of human depth perception of real objects in complex scenes.