“The effect of interocular separation on perceived depth from disparity in complex scenes”

K Benzeroual, S R. Laldin, L M. Wilcox, R S. Allison

The geometry of stereopsis makes straightforward predictions regarding the effect of increasing an observer’s simulated interocular distance (IO) on perceived depth. Our aim is to characterize the effect of IO on perceived depth, and its dependence on scene complexity and screen size. In Experiment 1 we used S3D movies of an indoor scene, shot with three camera separations (0.25″, 1″ and 1.7″). We displayed this footage on two screens (54″ and 22″) maintaining a constant visual angle. A reference scene with an IO of 1″ was displayed for 5s followed by the test scene. Participants (n=10) were asked to estimate the distances between four pairs of objects in the scene relative to the reference. Contrary to expectations, there was no consistent effect of IO, and all participants perceived more depth on the smaller screen. In Experiment 2 we used static line stimuli, with no real-world context. The same set of conditions was evaluated; all observers now perceived more depth in the larger display and there was a clear dependence on IO. The presence of multiple realistic depth cues has significant and complex effects on perceived depth from binocular disparity; effects that are not obvious from binocular geometry.