Typical stereoscopic displays produce a vivid impression of depth by presenting each eye with its own image on a flat display screen. This technique produces many depth signals (including disparity) that are consistent with a 3-dimensional (3d) scene; however, by using a flat display panel, focus information will be incorrect. The accommodation distance to the simulated objects will be at the screen distance, and blur will be inconsistent with the simulated depth.
In this thesis I will described several studies investigating the importance of focus cues for binocular vision. These studies reveal that there are a number of benefits to presenting correct focus information in a stereoscopic display, such as making it easier to fuse a binocular image, reducing visual fatigue, mitigating disparity scaling errors, and helping to resolve the binocular correspondence problem. For each of these problems, I discuss the theory for how focus cues could be an important factor, and then present psychophysical data showing that indeed focus cues do make a difference.
Next, I describe a new approach to construct a stereoscopic display that presents these signals correctly. This new display uses a custom lens system to present correct focus information in a time-multiplexed manner. This approach has significant advantages over other volumetric display approaches, and is a significant advancement in stereoscopic display technology.
In addition to the technical development of the volumetric display, I have also developed a way of analyzing volumetric displays to assess the retinal image quality of objects in various positions within the display. This model of image formation in a volumetric display allows us to test how various properties of the viewer, display and stereoscopic content will change the image quality. The main conclusion of this analysis is that a volumetric display requires only a coarse depth resolution to create stereoscopic images that are a close approximation of real-world images.