Unlike other inputs for extended reality (XR) that work out of the box, eye tracking typically requires custom calibration per user or session. We present a multimodal inputs approach for implicit calibration of eye tracker in VR, leveraging UI interaction for continuous, background calibration. Our method analyzes gaze data alongside controller interaction with UI elements, and employing ML techniques it continuously refines the calibration matrix without interrupting users from their current tasks. Potentially eliminating the need for explicit calibration. We demonstrate the accuracy and effectiveness of this implicit approach across various tasks and real time applications achieving comparable eye tracking accuracy to native, explicit calibration. While our evaluation focuses on VR and controller-based interactions, we anticipate the broader applicability of this approach to various XR devices and input modalities.

Although distance perception to Augmented Reality (AR) objects has been studied for decades, little is known about absolute distance perception with the newest available AR displays. One significant distinction in categories of head-worn AR displays is whether they are optical see-through (OST) or video see-through (VST). These two types of devices have different methods of rendering that could affect the cues available for perceiving distance. Specifically, rendering cast shadows can be challenging, especially in OST displays that rely on additive light for rendering, and there may be alternative shadow shading methods that are equally as effective for conveying cues to depth. The current study tests absolute egocentric distance judgments to targets 3-6 meters away from an observer with two types of shadows, in two types of AR displays, the Hololens 2 (OST) and the Varjo XR-3 (VST). Shadows were realistic cast shadows or non-realistic shadows in the form of a stylized ring placed beneath the object. Participants verbally reported perceived distance to spherical virtual targets presented on or above the ground, viewed through the displays in a real world classroom. We found overall distance underestimation in both devices, but that estimations were more accurate with the Hololens 2 compared to the Varjo XR-3. There was little support for a difference in accuracy of estimations between shadow conditions or position on or above the ground (confirmed by a Bayesian analysis), suggesting that non-realistic shadows may be a good option for providing additional shading cues for depth in AR.

Although it is commonly accepted that depth perception in augmented reality (AR) displays is distorted, we have yet to isolate which properties of AR affect people’s ability to correctly perceive virtual objects in real spaces. From prior research on depth perception in commercial virtual reality, it is likely that ergonomic properties and graphical limitations impact visual perception in head-mounted displays (HMDs). However, an insufficient amount of research has been conducted in augmented reality HMDs for us to begin isolating pertinent factors in this family of displays. To this end, in the current research, we evaluate absolute measures of distance perception in the Microsoft HoloLens 2, an optical see-through AR display, and the Varjo XR-3, a video see-through AR display. The current work is the first to evaluate either device using absolute distance perception as a measure. For each display, we asked participants to verbally report distance judgments to both grounded and floating targets that were rendered either with or without a cast shadow along the ground. Our findings suggest that currently available video see-through displays may induce more distance underestimation than their optical see-through counterparts. We also find that the vertical position of an object and the presence of a cast shadow influence depth perception.

Virtual objects in augmented reality (AR) often appear to float atop real world surfaces, which makes it difficult to determine where they are positioned in space. This is problematic as many applications for AR require accurate spatial perception. In the current study, we examine how the way we render cast shadows-which act as an important monocular depth cue for creating a sense of contact between an object and the surface beneath it-impacts spatial perception. Over two experiments, we evaluate people's sense of surface contact given both traditional and non-traditional shadow shading methods in optical see-through augmented reality (OST AR), video see-through augmented reality (VST AR), and virtual reality (VR) head-mounted displays. Our results provide evidence that nontraditional shading techniques for rendering shadows in AR displays may enhance the accuracy of one's perception of surface contact. This finding implies a possible tradeoff between photorealism and accuracy of depth perception, especially in OST AR displays. However, it also supports the use of more stylized graphics like non-traditional cast shadows to improve perception and interaction in AR applications.

Commodity-level virtual reality equipment is now available to all ages. To better understand how cognitive development affects people’s spatial memory in virtual reality, we assess how adults (20-29 years old) and teenagers (14-17 years old) represent their spatial memory of objects in an immersive virtual environment (IVE) where height is encoded. Despite virtual reality being a favorable conduit for the study of egocentric spatial memory, prior studies have predominately looked at objects placed at similar heights. Within a stairwell environment, participants learned the positions of nine target objects. In one condition, all objects were placed near eye height. In another, they were placed at varying heights. Our results indicate that participants’ errors and latencies were similar in both environments, and across age groups. Our results have implications for the development of IVEs and the expansion of immersive technology to a more diverse, younger audience.

The anatomy of the ear and the bones surrounding it are intricate yet critical for medical professionals to know. Current best practices teach ear anatomy through two-dimensional representations, which poorly characterize the three-dimensional (3D), spatial nature of the anatomy and make it difficult to learn and visualize. In this work, we describe an immersive, stereoscopic visualization tool for the anatomy of the ear based on real patient data. We describe the interface and its construction. And we compare how well medical students learn ear anatomy in the simulation compared with more traditional learning methods. Our preliminary results suggest that virtual reality may be an effective tool for anatomy education in this context.

Walking in place is a standard method for moving through large virtual environments when physical space or positional tracking is limited. This technique has become increasingly prominent with the advent of mobile virtual reality in which external tracking may not be present. In this paper, we revisit walking in place algorithms to address some of their technical challenges. Namely, our solutions attend to improving starting, stopping, and speed control for individual users. From a hand-tuned threshold based algorithm, we provide a new, fast method for individualizing the walking in place algorithm based on biomechanic measures of step rate. In addition, we introduce a new walking in place model based on a convolutional neural network trained to differentiate walking and standing. Over two experiments we assess these methods against a traditional threshold based algorithm on two mobile virtual reality platforms. The assessments are based on controllability, scale, and presence. Our results suggest that an adequately trained convolutional neural network can be an effective way of implementing walking in place.

Augmented reality (AR) technologies have the potential to provide individuals with unique training and visualizations, but the effectiveness of these applications may be influenced by users' perceptions of the distance to AR objects. Perceived distances to AR objects may be biased if these objects do not appear to make contact with the ground plane. The current work compared distance judgments of AR targets presented on the ground versus off the ground when no additional AR depth cues, such as shadows, were available to denote ground contact. We predicted that without additional information for height off the ground, observers would perceive the off-ground objects as placed on the ground, but at farther distances. Furthermore, this bias should be exaggerated when targets were viewed with one eye rather than two. In our experiment, participants judged the absolute egocentric distance to various cubes presented on or off the ground with an action-based measure, blind walking. We found that observers walked farther for off-ground AR objects and that this effect was exaggerated when participants viewed off-ground objects with monocular vision compared to binocular vision. However, we also found that the restriction of binocular cues influenced participants' distance judgments for on-ground AR objects. Our results suggest that distances to off-ground AR objects are perceived differently than on-ground AR objects and that the elimination of binocular cues further influences how users perceive these distances.

It is an open question as to whether people perceive and act in augmented reality environments in the same way that they do in real environments. The current work investigated participants' judgments of whether or not they could act on an obstacle portrayed with augmented reality. Specifically, we presented gaps of varying widths and depths to participants in augmented reality using the Microsoft HoloLens. We asked users to indicate whether or not they believed that they could step across the virtual gaps given their widths and depths. Averaging across changes in width and depth, users generally underestimated their abilities to cross gaps. However, this underestimation was significantly greater when the gaps were deep. Thus, our findings suggest that users in augmented reality respond with more conservative judgments when presented with risky stimuli-a response that mimics real world behavior. Their altered reactions to deeper gaps may provide early evidence for augmented reality's capacity to evoke a sense of realism or immersion and its use in evaluating perception and action.

Most virtual environments that people locomote through with head-mounted displays are flat to match the physical environment that people are actively walking on. In this paper we simulated stair climbing, and evaluated how well people could assess the distance they had climbed after several minutes of the activity under various conditions. We varied factors such as the presence of virtual feet (shoes), whether the stairwell was open or enclosed, the presence or absence of passive haptic markers, and whether a subject was ascending or descending. In general, the distance climbed or descended was overestimated, consistent with prior work on the perception of height. We find that subjects have significantly better ability to estimate their error with the presence of virtual shoes than without, and when the environment was open. Having shoes also resulted in significantly higher ratings of presence. We also find a significant tendency for females to show higher ratings of simulator sickness.

As virtual reality expands in popularity, an increasingly diverse audience is gaining exposure to immersive virtual environments (IVEs). A significant body of research has demonstrated how perception and action work in such environments, but most of this work has been done studying adults. Less is known about how physical and cognitive development affect perception and action in IVEs, particularly as applied to preteen and teenage children. Accordingly, in the current study we assess how preteens (children aged 8-12 years) and teenagers (children aged 15-18 years) respond to mismatches between their motor behavior and the visual information presented by an IVE. Over two experiments, we evaluate how these individuals recalibrate their actions across functionally distinct systems of movement. The first experiment analyzed forward walking recalibration after exposure to an IVE with either increased or decreased visual flow. Visual flow during normal bipedal locomotion was manipulated to be either twice or half as fast as the physical gait. The second experiment leveraged a prism throwing adaptation paradigm to test the effect of recalibration on throwing movement. In the first experiment, our results show no differences across age groups, although subjects generally experienced a post-exposure effect of shortened distance estimation after experiencing visually faster flow and longer distance estimation after experiencing visually slower flow. In the second experiment, subjects generally showed the typical prism adaptation behavior of a throwing after-effect error. The error lasted longer for preteens than older children. Our results have implications for the design of virtual systems with children as a target audience.

No abstract available.

Immersive virtual environments (VEs) allow people to experience situations which because of danger, expense, time, or distance would not otherwise be available. Moreover, IVEs have been shown to be useful tools for learning and training. However, there are still many unanswered questions about how humans experience and interact with these environments and how this experience differs from the real world. In the experiment presented in this work, we are specifically interested in how effectively two people will collaborate within an environment given that they have never met or even seen each other prior to the experiment. We postulate that participants who never meet their partner in a collaborative environment will perform worse than those who are able to interact with their partner prior to the performance of a task. If this holds true, then it could have important implications for long distance collaboration.