Motion in depth constancy in stereoscopic displays

Abstract

In a stereoscopic 3D scene, non-linear mapping between real space and disparity could produce distortions when camera geometry differs from natural stereoscopic geometry. When the viewing distance and zero screen parallax setting are held constant and interaxial separation is varied, there is an asymmetric distortion in the mapping of stereoscopic to real space. If an object traverses this space at constant velocity, one might anticipate distortion of the perceived velocity. To determine if the predicted distortions are in fact perceived, we assessed perceived acceleration and deceleration using an animation of a ball moving in depth through a simulated environment, viewed stereoscopically. The method of limits was used to measure transition points between perceived acceleration and deceleration as a function of interaxial and context (textured vs. non-textured background). Based on binocular geometry, we predicted that the transition points would shift toward deceleration for small and towards acceleration for large interaxial separations. However, the average transition values were not influenced by interaxial separation. These data suggest that observers are able to discount distortions of stereoscopic space in interpreting the object motion. These results have important implications for the rendering or capture of effective stereoscopic 3D content.