Depth cues in human visual perception and their realization in 3D displays

Over the last decade, various technologies for visualizing three-dimensional (3D) scenes on displays have been technologically demonstrated and refined, among them such of stereoscopic, multi-view, integral imaging, volumetric, or holographic type. Most of the current approaches utilize the conventional stereoscopic principle. But they all lack of their inherent conflict between vergence and accommodation since scene depth cannot be physically realized but only feigned by displaying two views of different perspective on a flat screen and delivering them to the corresponding left and right eye. This mismatch requires the viewer to override the physiologically coupled oculomotor processes of vergence and eye focus that may cause visual discomfort and fatigue. This paper discusses the depth cues in the human visual perception for both image quality and visual comfort of direct-view 3D displays. We concentrate our analysis especially on near-range depth cues, compare visual performance and depth-range capabilities of stereoscopic and holographic displays, and evaluate potential depth limitations of 3D displays from a physiological point of view.