37 research outputs found
Understanding and manipulating eye height to change the user's experience of perceived space in virtual reality
No full textToday, virtual reality technology is a multi-purpose tool for diverse applications in various domains. However, research has shown that virtual worlds are often not perceived in scale, especially regarding egocentric distances, as the programmer intended them. While the main reason for this misperception of distances in virtual environments is still unknown, this dissertation investigates one specific aspect of fundamental importance to distance perception ndash; eye height. In human perception, the ability to determine eye height is essential, because eye height is used to perceive heights of objects, velocity, affordances and distances, all of which allow for successful environmental interaction. It is reasonably well understood how eye height is used to determine many of these percepts. Yet, how eye height itself is determined is still unknown. In multiple studies conducted in virtual reality and the real world, this dissertation investigates how eye height might be determined in common scenarios in virtual reality. Using manipulations of the virtual eye height and distance perception tasks, the results suggest that humans rely more on their body-based information to determine their eye height, if they have no possibility for calibration. This has major implications for many existing virtual reality setups. Because humans rely on their body-based eye height, this can be exploited to systematically alter the perceived space in immersive virtual environments, which might be sufficient to enable every user an experience close to what was intended by the programmer
Welcome to Wonderland : the influence of the size and shape of a virtual hand on the perceived size and shape of virtual objects
No full textThe notion of body-based scaling suggests that our body and its action capabilities are used to scale the spatial layout of the environment. Here we present four studies supporting this perspective by showing that the hand acts as a metric which individuals use to scale the apparent sizes of objects in the environment. However to test this, one must be able to manipulate the size and/or dimensions of the perceiver’s hand which is difficult in the real world due to impliability of hand dimensions. To overcome this limitation, we used virtual reality to manipulate dimensions of participants’ fully-tracked, virtual hands to investigate its influence on the perceived size and shape of virtual objects. In a series of experiments, using several measures, we show that individuals’ estimations of the sizes of virtual objects differ depending on the size of their virtual hand in the direction consistent with the body-based scaling hypothesis. Additionally, we found that these effects were specific to participants’ virtual hands rather than another avatar’s hands or a salient familiar-sized object. While these studies provide support for a body-based approach to the scaling of the spatial layout, they also demonstrate the influence of virtual bodies on perception of virtual environments
The importance of postural cues for determining eye height in immersive virtual reality.
No full textIn human perception, the ability to determine eye height is essential, because eye height is used to scale heights of objects, velocities, affordances and distances, all of which allow for successful environmental interaction. It is well understood that eye height is fundamental to determine many of these percepts. Yet, how eye height itself is provided is still largely unknown. While the information potentially specifying eye height in the real world is naturally coincident in an environment with a regular ground surface, these sources of information can be easily divergent in similar and common virtual reality scenarios. Thus, we conducted virtual reality experiments where we manipulated the virtual eye height in a distance perception task to investigate how eye height might be determined in such a scenario. We found that humans rely more on their postural cues for determining their eye height if there is a conflict between visual and postural information and little opportunity for perceptual-motor calibration is provided. This is demonstrated by the predictable variations in their distance estimates. Our results suggest that the eye height in such circumstances is informed by postural cues when estimating egocentric distances in virtual reality and consequently, does not depend on an internalized value for eye height
Eye height manipulations : a possible solution to reduce underestimation of egocentric distances in head-mounted displays
No full textVirtual reality technology can be considered a multipurpose tool for diverse applications in various domains, for example, training, prototyping, design, entertainment, and research investigating human perception. However, for many of these applications, it is necessary that the designed and computer-generated virtual environments are perceived as a replica of the real world. Many research studies have shown that this is not necessarily the case. Specifically, egocentric distances are underestimated compared to real-world estimates regardless of whether the virtual environment is displayed in a head-mounted display or on an immersive large-screen display. While the main reason for this observed distance underestimation is still unknown, we investigate a potential approach to reduce or even eliminate this distance underestimation. Building up on the angle of declination below the horizon relationship for perceiving egocentric distances, we describe how eye height manipulations in virtual reality should affect perceived distances. In addition, we describe how this relationship could be exploited to reduce distance underestimation for individual users. In a first experiment, we investigate the influence of a manipulated eye height on an action-based measure of egocentric distance perception. We found that eye height manipulations have similar predictable effects on an action-based measure of egocentric distance as we previously observed for a cognitive measure. This might make this approach more useful than other proposed solutions across different scenarios in various domains, for example, for collaborative tasks. In three additional experiments, we investigate the influence of an individualized manipulation of eye height to reduce distance underestimation in a sparse-cue and a rich-cue environment. In these experiments, we demonstrate that a simple eye height manipulation can be used to selectively alter perceived distances on an individual basis, which could be helpful to enable every user to have an experience close to what was intended by the content designer
Illustration of body based scaling measurements across different hand width conditions.
No full text<p>Illustration of body based scaling measurements across different hand width conditions.</p
Experimental setup for Experiment 3 with respect to the participants’ viewpoints in the three different pen size conditions.
No full text<p>Experimental setup for Experiment 3 with respect to the participants’ viewpoints in the three different pen size conditions.</p
Change in proportion of perceived length responses between large and small hand width condition as a function of the proportional change in perceived grasping ability between the large and small hand width conditions.
No full text<p>Each circle represents one participant’s data, and the solid line is the correlation between the two plotted variables.</p
Prediction based on the use of a combination of the visually specified angle of declination (AoD<sub>v</sub>) and the postural eye height (EH<sub>pos</sub>) of the observer regardless of the potentially displayed environment.
No full text<p>In the case illustrated, underestimation of the distance is predicted, whereas for a lowered virtual EH overestimation of the distance is predicted. <b>Note:</b> The camera symbol represents the manipulated virtual EH.</p
Mean verbal estimate of spheres for the three conditions of hand size (large, medium and small).
No full text<p>Error bars represent 1 standard error and are calculated on the basis of within-participant error with the method provided by Loftus and Masson [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068594#B37" target="_blank">37</a>]. The line labeled “Actual Size” indicates the mean of actual physical size of the stimuli with respect to the verbal scale.</p
