An experimental comparison of perceived egocentric distance in real, image-based, and traditional virtual environment using direct walking tasks

technical reportIn virtual environments, perceived egocentric distances are often underestimated when compared to the same distance judgments in the real world. The research presented in this paper explores two possible causes for this reduced distance perception in virtual environments: (1) real-time computer graphics rendering, and (2) immersive display technology. Our experiment compared egocentric distance judgments in three complex, indoor environments: a real hallway with full-cue conditions; a virtual, stereoscopic, photographic panorama; and a virtual, stereoscopic computer model. Perceived egocentric distance was determined by a directed walking task in which subjects walk blindfolded to the target. Our results show there is a significant difference in distance judgments between real and virtual environments. However, the differences between distance judgments in virtual photographic panorama environments and traditionally rendered virtual environments are small, suggesting that the display device is affecting distance judgments in virtual environments

Perceiving environmental structure from optical motion

Generally speaking, one of the most important sources of optical information about environmental structure is known to be the deforming optical patterns produced by the movements of the observer (pilot) or environmental objects. As an observer moves through a rigid environment, the projected optical patterns of environmental objects are systematically transformed according to their orientations and positions in 3D space relative to those of the observer. The detailed characteristics of these deforming optical patterns carry information about the 3D structure of the objects and about their locations and orientations relative to those of the observer. The specific geometrical properties of moving images that may constitute visually detected information about the shapes and locations of environmental objects is examined

Size and shape constancy in consumer virtual reality

With the increase in popularity of consumer virtual reality headsets, for research and other applications, it is important to understand the accuracy of 3D perception in VR. We investigated the perceptual accuracy of near-field virtual distances using a size and shape constancy task, in two commercially available devices. Participants wore either the HTC Vive or the Oculus Rift and adjusted the size of a virtual stimulus to match the geometric qualities (size and depth) of a physical stimulus they were able to refer to haptically. The judgments participants made allowed for an indirect measure of their perception of the egocentric, virtual distance to the stimuli. The data show under-constancy and are consistent with research from carefully calibrated psychophysical techniques. There was no difference in the degree of constancy found in the two headsets. We conclude that consumer virtual reality headsets provide a sufficiently high degree of accuracy in distance perception, to allow them to be used confidently in future experimental vision science, and other research applications in psychology

Stereo TV enhancement study Final technical report

Human depth perception of television displays in stereo, and nonstereo presentation

Controlled Interaction: Strategies For Using Virtual Reality To Study Perception

Immersive virtual reality systems employing head-mounted displays offer great promise for the investigation of perception and action, but there are well-documented limitations to most virtual reality systems. In the present article, we suggest strategies for studying perception/action interactions that try to depend on both scale-invariant metrics (such as power function exponents) and careful consideration of the requirements of the interactions under investigation. New data concerning the effect of pincushion distortion on the perception of surface orientation are presented, as well as data documenting the perception of dynamic distortions associated with head movements with uncorrected optics. A review of several successful uses of virtual reality to study the interaction of perception and action emphasizes scale-free analysis strategies that can achieve theoretical goals while minimizing assumptions about the accuracy of virtual simulations

Midpoint estimation applied to the vertical-horizontal illusion

Eighty-three college undergraduates estimated midpoints of vertical lines presented in cued (a letter or figure presented below the line), uncued, and inverted T conditions. Subject\u27s mean estimates were near the geometric midpoint in the two cued conditions, and significantly above the midpoint in the uncued and inverted T conditions. Mean estimates in the inverted T conditions were significantly above those in the uncued condition. These displacements are discussed in relation to previous midpoint estimation findings and theoretical explanations of the vertical-horizontal illusion. The midpoint estimation task is evaluated as an investigative tool in studies of geometric-optical illusions, and recommendations for further study are suggested

Effect of short-term exposure to stereoscopic three-dimensional flight displays on real-world depth perception

High-fidelity color pictorial displays that incorporate depth cues in the display elements are currently available. Depth cuing applied to advanced head-down flight display concepts potentially enhances the pilot's situational awareness and improves task performance. Depth cues provided by stereopsis exhibit constraints that must be fully understood so depth cuing enhancements can be adequately realized and exploited. A fundamental issue (the goal of this investigation) is whether the use of head-down stereoscopic displays in flight applications degrade the real-world depth perception of pilots using such displays. Stereoacuity tests are used in this study as the measure of interest. Eight pilots flew repeated simulated landing approaches using both nonstereo and stereo 3-D head-down pathway-in-the-sky displays. At this decision height of each approach (where the pilot changes to an out-the-window view to obtain real-world visual references) the pilots changed to a stereoacuity test that used real objects. Statistical analysis of stereoacuity measures (data for a control condition of no exposure to any electronic flight display compared with data for changes from nonstereo and from stereo displays) reveals no significant differences for any of the conditions. Therefore, changing from short-term exposure to a head-down stereo display has no more effect on real-world relative depth perception than does changing from a nonstereo display. However, depth perception effects based on sized and distance judgements and on long-term exposure remain issues to be investigated

Conversions of Relief: on the perception of depth in drawings

Of the many ways in which depth can be intimated in drawings, perspective has undoubtedly been one of the most frequently examined. But there is also an equally rich history associated with other forms of pictorial representation. Alternatives to perspective became particularly significant in the early twentieth century as artists and architects, intent on throwing off the conventions of their predecessors, looked to new ways of depicting depth. In architecture, this tendency was exemplified by Modernism’s preference for parallel projection – most notably axonometric and oblique. The use of these techniques gave architects the opportunity to convey a new and uniquely modern form of spatial expression. At once shallow and yet expansive, a key feature of these drawings was their ability to support perceptual ambiguity. This paper will consider the philosophy and science of vision, out of which these preoccupations emerged. In this context, the nineteenth-century discovery of stereopsis and the invention of the stereoscope will be used to illustrate the way in which attempts to test the limits of spatial perception led to an opening up of visual experience; and provided a definition of visual experience that could encompass the representational ambiguities later exploited by the early twentieth-century avant-garde