Bobby Bodenheimer

• Doctor of Philosophy
• Professor (Associate) at Vanderbilt University

Omnidirectional treadmills provide one solution for locomoting through large virtual environments in confined physical spaces. Through two experiments, this paper evaluated locomotion on an omnidirectional treadmill (Cyberith Virtualizer Elite 2) by comparing it to natural walking in an open physical space. In Experiment 1, participants judged dist...

Most modern head-mounted displays (HMDs) do not support the full range of adult inter-pupillary distances (IPDs) (i.e., 45 – 80 mm) due to technological limitations. Prior work indicates that the mismatch between a user’s actual IPD and the IPD set in the HMD (“IPD mismatch”) can affect distance and size judgments in near space (0 – 2 m). Therefore...

As applications for virtual reality (VR) and augmented reality (AR) technology increase, it will be important to understand how users perceive their action capabilities in virtual environments. Feedback about actions may help to calibrate perception for action opportunities (affordances) so that action judgments in VR and AR mirror actors’ real abi...

Daily travel usually demands navigation on foot across a variety of different application domains, including tasks like search and rescue or commuting. Head-mounted augmented reality (AR) displays provide a preview of future navigation systems on foot, but designing them is still an open problem. In this paper, we look at two choices that such AR s...

Decades of research have shown that absolute egocentric distance is underestimated in virtual environments (VEs) when compared with the real world. This finding has implications on the use of VEs for applications that require an accurate sense of absolute scale. Fortunately, this underperception of scale can be attenuated by several factors, making...

Prior work on depth perception in commercial augmented reality (AR) has indicated that egocentric distances are underestimated. One hypothesis as to why distances may be misjudged is an inability of the viewer to correctly perceive that a virtual object has surface contact with the ground rather than is floating above it. There are several factors...

Augmented Reality (AR) experiments are typically implemented in controlled conditions that are guided by experimenters. The paucity of research on remote AR experiments leads to difficulties for many researchers when conducting remote user studies. Our work provides a preliminary investigation of spatial perception in AR via mobile devices. The ini...

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 graphica...

In this paper, we examine how embodiment and manipulation of a self-avatar's dimensions - specifically the arm length - affect users' judgments of the personal space around them in an immersive virtual environment. In the real world, personal space is the immediate space around the body in which physical interactions are possible. Personal space is...

The information provided to a person's visual system by extended reality (XR) displays is not a veridical match to the information provided by the real world. Due in part to graphical limitations in XR head-mounted displays (HMDs), which vary by device, our perception of space may be altered. However, we do not yet know which properties of virtual...

Spatial perception in immersive virtual environments, particularly regarding distance perception, is a well-studied topic in virtual reality literature. Distance compression, or the underestimation of distances, is and has been historically prevalent in all virtual reality systems. The problem of distance compression still remains open, but recent...

Although Augmented Reality (AR) can be easily implemented with most smartphones and tablets today, the investigation of distance perception with these types of devices has been limited. In this paper, we question whether the distance of a virtual human, e.g., avatar, seen through a smartphone or tablet display is perceived accurately. We also inves...

Abstract Background: With Augmented Reality (AR), people interact with virtual content displayed within the real environment. AR cues and objects can be used to conduct rigorously controlled experiments to understand the mechanisms underlying human perception of the environment. Prior work has investigated whether the addition of AR cues to the re...

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 monocu...

Augmented reality is standard on many modern smartphone platforms. The distance of virtual objects seen through the smartphone display should be perceived accurately for easy interaction with virtual objects with high fidelity. We investigate whether distance perception through mobile augmented reality devices is affected by an animated avatar. The...

Self-disturbances such as an anomalous perception of one’s own body boundary are central to the phenomenology of schizophrenia (SZ), but measuring the spatial parameters of the hypothesized self–other boundary has proved to be challenging. Peripersonal space (PPS) refers to the immediate zone surrounding the body where the self interacts physically...

We investigated two judgments of action capabilities with virtual objects presented through smartphones: passing through an aperture and stepping over a gap. The results showed that users were conservative in their affordance judgments for the two actions, but that judgments became more accurate with training by AR cues. In the post-cue trials, pas...

Measures of perceived affordances—judgments of action capabilities—are an objective way to assess whether users perceive mediated environments similarly to the real world. Previous studies suggest that judgments of stepping over a virtual gap using augmented reality (AR) are underestimated relative to judgments of real-world gaps, which are general...

The privacy and security of personal data has been at the forefront of public concern for some time now, and is typically understood in the context of data collected from online interaction (social media, transactions, search engine queries, etc.). The advent of immersive technologies expand data collection beyond what can typically be extracted vi...

Although immersive virtual reality is attractive to users, we know relatively little about whether higher immersion levels increase or decrease spatial learning outcomes. In addition, questions remain about how different approaches to travel within a virtual environment affect spatial learning. In this paper, we investigated the role of immersion (...

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....

Information about a patient's state is critical for hospitals to provide timely care and treatment. Prior work on improving the information flow from emergency medical services (EMS) to hospitals demonstrated the potential of using automated algorithms to detect clinical procedures. However, prior work has not made effective use of video sources th...

Augmented reality is an important technology for learning and training, particularly in such tasks as navigation and assembly. These tasks typically require that people be able to accurately localize the position of objects in space; in the case of augmented reality applications, these objects would include virtual objects. Prior work suggests that...

Affordances are possibilities for action that depend on both an observer's capabilities and the properties of the environment. Immersive Virtual Environments (IVEs) have been used to examine affordances in adults, demonstrating that judgments about action capabilities are made similarly to the real world. However, less is known about affordance jud...

Navigation, or the means by which people find their way in an environment, depends on the ability to combine information from multiple sources so that properties of an environment, such as the location of a goal, can be estimated. An important source of information for navigation are spatial cues generated by self-motion. Navigation based solely on...

Recent advancements in augmented reality (AR) have led to the development of several applications in domains such as architecture, engineering, and medical training. Typically, these applications present users with 3D virtual images in real environments that would not easily be portrayed otherwise (e.g., floor plans, arteries, etc.). The way users...

Understanding a patient's state is critical to providing optimal care. However, information loss occurs during patient hand-offs (e.g., emergency services (EMS) transferring patient care to a receiving hospital), which hinders care quality. Augmenting the information flow from an EMS vehicle to a receiving hospital may reduce information loss and i...

Virtual Environments (VEs) presented through head-mounted displays (HMDs) are often explored on foot. This type of exploration is useful since the inertial cues of physical locomotion aid spatial awareness. However, the size of the VE that can be explored on foot is limited to the dimensions of the tracking space of the HMD unless locomotion is som...

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...

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 part...

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 descri...

An essential question in understanding how to develop and build collaborative immersive virtual environments (IVEs) is recognizing how people perform actions together. Many actions in the real world require that people act without prior planning, and these actions are executed quite successfully. In this paper, we study the common action of two peo...

This work investigates how pedestrian street crossing behavior at a virtual traffic roundabout is affected by central visual field loss. We exposed participants with normal vision to a first-person virtual experience of central visual field loss of variable size in the form of a simulated scotoma, an area of the visual field with degraded visual ac...

In the current study, we investigated the ways in which the acquisition and transfer of spatial knowledge were affected by (a) the type of spatial relations predominately experienced during learning (routes determined by walkways vs. straight-line paths between locations); (b) environmental complexity; and (c) the availability of rotational body-ba...

The utility of mediated environments increases when environmental scale (size and distance) is perceived accurately. We present the use of perceived affordances---judgments of action capabilities---as an objective way to assess space perception in an augmented reality (AR) environment. The current study extends the previous use of this methodology...

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 varie...

Children have begun to use virtual reality with increasing frequency ; however, it is uncertain how immersive virtual environments affect a child's understanding of three dimensional space. We present preliminary work evaluating the spatial memory of children across real and virtual worlds. We assess 10 children (aged 9-12) and 9 teenagers (aged 16...

Underestimation of egocentric distances in immersive virtual environments using various head-mounted displays (HMDs) has been a puzzling topic of research interest for several years. As more commodity-level systems become available to developers, it is important to test the variation of underestimation in each system since reasons for underestimati...

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...

Locomotion in large virtual environments is currently unsupported in smartphone-powered virtual reality headsets, particularly within the confines of limited physical space. While motion controllers are a workaround for this issue, they exhibit known problems: they occupy the subject's hands, and they cause poor navigation performance. In this pape...

When dissimilar monocular images are viewed simultaneously by the two eyes, stable binocular vision gives way to unstable vision characterized by alternations in dominance between the two images in a phenomenon called binocular rivalry. These alternations in perception reveal the existence of inhibitory interactions between neural representations a...

Collaborative immersive virtual environments allow the behavior of one user to be observed by other users. In particular, behavior of users in such an environment is represented by each user possessing a self-avatar, a digital representation of themself. In this study we examined dyadic interactions in a collaborative immersive virtual environment...

People judge what they can and cannot do all the time when acting in the physical world. Can I step over that fence or do I need to duck under it? Can I step off of that ledge or do I need to climb off of it? These qualities of the environment that people perceive that allow them to act are called affordances. This article compares people's judgmen...

We present a new depth from defocus method based on the assumption that a per pixel blur estimate (related with the circle of confusion), while ambiguous for a single image, behaves in a consistent way when applied over a focal stack of two or more images. This allows us to fit a simple analytical description of the circle of confusion to the diffe...

When two eyes view different objects or scenes at the same time, stable binocular single vision gives way to alternations in perception. Called binocular rivalry, this beguiling phenomenon discloses the existence of inhibitory interactions between neural representations associated with the conflicting visual inputs. One strategy for learning detail...

A previous study, Young et al. [2014], explored comparisons between cost-differentiated head-mounted displays for the evaluation of various perception and action tasks. One of the comparisons in that work was egocentric distance estimation comparison using an Nvis SX 60 head-mounted display (HMD) and an Oculus Rift. This poster abstract supplements...

Recent advances in technology and the opportunity to obtain commodity-level components have made the development and use of three-dimensional virtual environments more available than ever before. How well such components work to generate realistic virtual environments, particularly environments suitable for perception and action studies, is an open...

The results of multiple studies conducted in the real world have demonstrated that human observers are usually very accurate in judging egocentric distance (the distance from the observer to a target) up to about 25 meters if the target is located on a continuous ground surface. Sinai et al. [1998] found that the presence of a texture discontinuity...

In this study, we examine subjects' spatial orientation in a head--mounted display (HMD) based virtual environment (VE) when objects are placed at different vertical viewing angles. More specifically, we examine spatial orientation when subjects memorize the location of objects on the ground, at eyelevel, and up in the air. Interestingly, we found...

We explore whether a gender-matched, calibrated self-avatar affects the perception of the affordance of stepping off of a ledge, or visual cliff, in an immersive virtual environment. Visual cliffs form demonstrations in many immersive virtual environments because they create compelling environments. Understanding the role that self-avatars contribu...

This experiment investigates the perceived differences in the quality of animation generated using motion capture data using a Vicon motion capture system and a Microsoft Kinect sensor. The Kinect uses a depth map camera to determine the position of users and objects within the view of the camera. Using this information, the depth map can be proces...

This experiment investigates the spatial memory and attention when human acts as supervisor of one or two groups of distributed robot teams in a large virtual environment (VE). The problem is similar to learning a new environment and interpreting its spatial structure, e.g., [Mou and McNamara 2002], but less is known when attention is divided or lo...

The purpose of this study was to learn if self-avatars influence people's perception and action in virtual environments. People viewed two situations in a virtual environment through a head-mounted display and were asked to decide how they would act. In one situation their task was to imagine walking across a room which was divided by a horizontal...

This paper presents a mixed reality system for combining real robots, humans, and virtual robots. The system tracks and controls physical robots in local physical space, and inserts them into a virtual environment (VE). The system allows a human to locomote in a VE larger than the physically tracked space of the laboratory through a form of redirec...

Humans have been shown to perceive and perform actions differently in immersive virtual environments (VEs) as compared to the real world. Immersive VEs often lack the presence of virtual characters; users are rarely presented with a representation of their own body and have little to no experience with other human avatars/characters. However, virtu...

We conducted a followup experiment to the work of Lin et al. [2011]. The experimental protocol was the same as that of Experiment Four in Lin et al. [2011] except the viewing condition was binocular instead of monocular. In that work there was no distance underestimation, as has been widely reported elsewhere, and we were motivated in this experime...

We conducted four experiments on egocentric depth perception using blind walking with a restricted scanning method in both the real and a virtual environment. Our viewing condition in all experiments was monocular. We varied the field of view (real), scan direction (real), blind walking method (real and virtual), and self-representation (virtual) o...

The trend in immersive virtual environments (VEs) is to include the users in a more active role by having them interact with the environment and objects within the environment. Studying action and perception in VEs, then, becomes an increasingly interesting and important topic to study. We chose to study a user's ability to judge errors in self-pro...

This experiment investigates source point localization using only auditory cues. The idea is to determine how well humans can localize and reason about space using only sound cues, and to determine how different sound cues effect performance in such tasks. The findings from this line of research can be used in enhancing audio in virtual environment...

McManus et al. [2011] studied a user's ability to judge errors in self-produced motion; more specifically, throwing. We now take the first step towards discriminating what cues subjects are using in order to make their judgments. The endpoint of the ball is one such cue; the restricted field of view (FOV) of the head mounted display (HMD) makes it...

In this work, we present a method of “Walking In Place” (WIP) on the Nintendo Wii Fit Balance Board to explore a virtual environment. We directly compare our method to joystick locomotion and normal walking. The joystick proves inferior to physically walking and to WIP on the Wii Balance Board (WIP--Wii). Interestingly, we find that physically expl...

Physical rotations and translations are the basic constituents of navigation behavior, yet there is mixed evidence about their relative importance for complex navigation in virtual reality (VR). In the present experiment, 24 participants wore head-mounted displays and performed navigational search tasks with rotations/translations controlled by phy...

This paper evaluates the combination of two methods for adapting bipedal locomotion to explore virtual environments displayed on head-mounted displays (HMDs) within the confines of limited tracking spaces. We combine a method of changing the optic flow of locomotion, effectively scaling the translational gain, with a method of intervening and manip...

Spatial updating, the process of updating one's perceived orientation and location during movement, is critical to many spatial behaviors relevant to navigation. This experiment investigated the relative influences of two types of cues during spatial updating: self-motion cues and environmental shape cues. Self-motion cues by themselves are noisy a...

Desktop virtual reality (VR) provides a more economical and ubiquitous way to present virtual reality to people, at the cost of a significant amount of immersion. Our study explores the addition of a low-cost head-tracking system to a desktop VR system and its impact on spatial cognition. The head-tracking system is used to provide a more 3D-like i...

In this paper, we use an immersive virtual environment to assess the separation, or "gap," between moving vehicles that people need before initiating a street crossing in a roundabout, where traffic can be approaching from several directions. From a pedestrians viewpoint, crossing at a roundabout can represent a more complex decision than at a norm...

ABSTRACT This article describes the design decisions, technical approach, and evaluation of the animation and interface components,for an agent-based,system that allows learners to learn by teaching. Students learn by teaching,an animated,agent using a visual representation. The agent can answer questions about what she has been taught and take qui...

Two experiments explored the role of environmental cues in maintaining spatial orientation (sense of self-location and direction) during locomotion. Of particular interest was the importance of geometric cues (provided by environmental surfaces) and featural cues (nongeometric properties provided by striped walls) in maintaining spatial orientation...

Considerable evidence shows that people have difficulty maintaining orientation in virtual environments. This difficulty is usually attributed to poor idiothetic cues, such as the absence of proprioception. The absence of proprioceptive cues makes a strong argument against the use of a joystick interface for locomotion. The importance of full physi...