This research investigated how the similarity of the rendering parameters of background and foreground objects affected egocentric depth perception in indoor virtual and augmented environments. We refer to the similarity of the rendering parameters as visual 'congruence'. Study participants manipulated the depth of a sphere to match the depth of a designated target peg. In the first experiment, the sphere and peg were both virtual, while in the second experiment, the sphere is virtual and the peg is real. In both experiments, depth perception accuracy was found to depend on the levels of realism and congruence between the sphere, pegs, and background. In Experiment 1, realistic backgrounds lead to overestimation of depth, but resulted in underestimation when the background was virtual, and when depth cues were applied to the sphere and target peg. In Experiment 2, background and target pegs were real but matched with the virtual sphere; in comparison to Experiment 1, realistically rendered targets prompted an underestimation and more accuracy with the manipulated object. These findings suggest that congruence can affect distance estimation and the underestimation effect in the AR environment resulted from increased graphical fidelity of the foreground target and background.

Multi-scale virtual environments contain geometric details ranging over several orders of magnitude and typically employ out-of-core rendering techniques. When displayed in virtual reality systems this entails using a 7 degree-of-freedom (DOF) view model where view scale is a separate 7th DOF in addition to 6DOF view pose. Dynamic adjustment of this and other view parameters become very important to usability. In this paper, we evaluate how two adjustment techniques interact with uni- and bi-manual 7DOF navigation in DesktopVR and a CAVE. The travel task has two stages, an initial targeted zoom and a detailed geometric inspection. The results show benefits of the auto-adjustments on completion time and stereo fusion issues, but only in certain circumstances. Peculiar view configuration examples show the difficulty of creating robust adjustment rules.

It is our great pleasure to welcome you to Greenville, South Carolina, for the IEEE Conference on Virtual Reality (IEEE VR) 2016. This is the 18th year of the premiere conference in virtual reality and 3D interaction in the world, and we are proud to host it here in South Carolina. In recent years, the conference has travelled to Singapore, Orange County, USA, Orlando, USA, Minneapolis, USA, and Arles, France. During these years the conference has grown in many respects, yet the basic format of mostly a single-track technical session has changed little. This year's conference, however, will feature some notable departures from previous years while still keeping with our cherished traditions of the IEEE VR conference.

Displays supporting stereoscopy and head-coupled motion parallax can enhance human perception of complex 3D datasets. This has been studied extensively for datasets containing 3D surfaces and 3D networks but less for so volumetric data. Volumetric data is characterized by a heavy presence of transparency, occlusion and highly ambiguous spatial structure. There are many different rendering and visualization algorithms and interactive techniques that enhance perception of volume data and these techniques' effectiveness have been evaluated. However, the effect of VR displays on perception of volume data is less well studied. Therefore, we conduct two experiments on how various display conditions affect a participant's depth perception accuracy of a volumetric dataset. A demographic pre-questionnaire also allows us to separate the accuracy differences between participants with more and less experience with 3D games and VR. Our results show an overall benefit for stereo with head-tracking for enhancing perception of depth in volumetric data. Our study also suggests that familiarity with 3D games and VR type technology affects the users'ability to perceive such data and affects the accuracy boost due to VR displays.

Displays supporting stereopsis and head location based motion parallax can enhance human perception of complex three dimensional datasets. This has been demonstrated for datasets containing 3D surfaces and 3D networks. Yet many domains, such as medical imaging, weather and environment simulations and fluid flow, generate complex volumetric data. This poster present results of an initial formal experiment that examines the effectiveness of various display conditions on depth perception of volumetric data. There is an overall benefit for stereoscopy with head-tracking in enhancing depth perception. Further, familiarity with 3D games and VR-like hardware improves the users'ability to perceive such data.

We present change blindness redirection, a novel technique for allowing the user to walk through an immersive virtual environment that is considerably larger than the available physical workspace. In contrast to previous redirection techniques, this approach, based on a dynamic environment model, does not introduce any visual-vestibular conflicts from manipulating the mapping between physical and virtual motions, nor does it require breaking presence to stop and explicitly reorient the user. We conducted two user studies to evaluate the effectiveness of the change blindness illusion when exploring a virtual environment that was an order of magnitude larger than the physical walking space. Despite the dynamically changing environment, participants were able to draw coherent sketch maps of the environment structure, and pointing task results indicated that they were able to maintain their spatial orientation within the virtual world. Only one out of 77 participants across both both studies definitively noticed that a scene change had occurred, suggesting that change blindness redirection provides a remarkably compelling illusion. Secondary findings revealed that a wide field-of-view increases pointing accuracy and that experienced gamers reported greater sense of presence than those with little or no experience with 3D video games.

We present a technique for exploiting change blindness to allow the user to walk through an immersive virtual environment that is much larger than the available physical workspace. This approach relies on subtle manipulations to the geometry of a dynamic environment model to redirect the user's walking path without becoming noticeable. We describe a virtual environment which was implemented both as a proof-of-concept and a test case for future evaluation. Anecdotal evidence from our informal tests suggest a compelling illusion, though a formal study against existing methods is required to evaluate the usefulness of this technique.

Abstract We present a probe‐based interface for the exploration of the results of a geospatial simulation of urban growth. Because our interface allows the user great freedom in how they choose to define regions‐of‐interest to examine and compare, the classic geospatial analytic issue known as the modifiable areal unit problem (MAUP) quickly arises. The user may delineate regions with unseen differences that can affect the fairness of the comparisons made between them. To alleviate this problem, our interface first alerts the user if it detects any potential unfairness between regions when they are selected for comparison. It then presents the dimensions with potential problematic outliers to the user for evaluation. Finally, it provides a number of semi‐automated tools to assist the user in correcting their regions' boundaries to minimize the inequalities they feel could significantly impact their comparisons.

Abstract Many previous approaches to detecting urban change from LIDAR point clouds interpolate the points into rasters, perform pixel‐based image processing to detect changes, and produce 2D images as output. We present a method of LIDAR change detection that maintains accuracy by only using the raw, irregularly spaced LIDAR points, and extracts relevant changes as individual 3D models. We then utilize these models, alongside existing GIS data, within an interactive application that allows the chronological exploration of the changes to an urban environment. A three‐tiered level‐of‐detail system maintains a scale‐appropriate, legible visual representation across the entire range of view scales, from individual changes such as buildings and trees, to groups of changes such as new residential developments, deforestation, and construction sites, and finally to larger regions such as neighborhoods and districts of a city that are emerging or undergoing revitalization. Tools are provided to assist the visual analysis by urban planners and historians through semantic categorization and filtering of the changes presented.

Traditional geospatial information visualizations often present views that restrict the user to a single perspective. When zoomed out, local trends and anomalies become suppressed and lost; when zoomed in for local inspection, spatial awareness and comparison between regions become limited. In our model, coordinated visualizations are integrated within individual probe interfaces, which depict the local data in user-defined regions-of-interest. Our probe concept can be incorporated into a variety of geospatial visualizations to empower users with the ability to observe, coordinate, and compare data across multiple local regions. It is especially useful when dealing with complex simulations or analyses where behavior in various localities differs from other localities and from the system as a whole. We illustrate the effectiveness of our technique over traditional interfaces by incorporating it within three existing geospatial visualization systems: an agent-based social simulation, a census data exploration tool, and an 3D GIS environment for analyzing urban change over time. In each case, the probe-based interaction enhances spatial awareness, improves inspection and comparison capabilities, expands the range of scopes, and facilitates collaboration among multiple users.

Using both hands for 3D interaction allows users to transfer ingrained interaction skills, significantly increase performance on certain tasks, and reduce training [Bowman et al. 2005]. Guiard's framework of Bimanual manipulation states that different classes of bimanual actions exist [1997]. The Bimanual Asymmetric classification consists of both hands, performing different actions, coordinated to accomplish the same task. The Bimanual Symmetric classification involves each hand performing identical actions, either synchronously or asynchronously. Latulipe et al. compared a symmetric, dual-mouse technique for manipulation of spline curves, to two asymmetric dual-mouse techniques and a standard single-mouse technique. The symmetric technique performed best and was most preferred by participants [2006].

This poster explores navigation, interaction and stereoscopic display in a multi-scale virtual space. When interaction, especially two-handed, direct manipulation, is combined with stereoscopic stationary displays, there are trade-offs that must be considered. This poster gives an overview of these design issues and briefly describes our current multi-scale, application for exploring volumetric weather in its geospatial context in a VR system. The general importance of recognizing and using defined areas of user focus and of semi-automatically bringing these areas into the optimal interaction volume of the display system is described.

This paper concerns stereoscopic virtual reality displays in which the head is tracked and the display is stationary, attached to a desk, tabletop or wall. These are called stereoscopic HTDs (head-tracked displays). Stereoscopic displays render two perspective views of a scene, each of which is seen by one eye of the user. Ideally, the user's natural visual system combines the stereo image pair into a single, 3D perceived image. Unfortunately, users often have difficulty fusing the stereo image pair. Researchers use a number of software techniques to reduce fusion problems. This paper geometrically examines and compares a number of these techniques and reaches the following conclusions: In interactive stereoscopic applications, the combination of view placement, scale, and either false eye separation or /spl alpha/-false eye separation can provide fusion control that is geometrically similar to image shifting and image scaling. However, in stereo HTDs, image shifting and image scaling also generate additional geometric artifacts that are not generated by the other methods. We anecdotally link some of these artifacts to exceeding the perceptual limitations of human vision. While formal perceptual studies are still needed, geometric analysis suggests that image shifting and image scaling may be less appropriate than the other methods for interactive, stereo HTDs.

The Perceptive Workbench enables a spontaneous, natural and unimpeded interface between the physical and virtual worlds. It uses vision-based methods for interaction that eliminate the need for wired input devices and wired tracking. Objects are recognized and tracked when placed on the display surface. Through the use of multiple light sources, the object's 3D shape can be captured and inserted into the virtual interface. This ability permits spontaneity since either preloaded objects or those objects selected on-the-spot by the user can become physical icons. Integrated into the same vision-based interface is the ability to identify 3D hand position, pointing direction and sweeping arm gestures. Such gestures can enhance selection, manipulation and navigation tasks. In this paper, the Perceptive Workbench is used for augmented reality gaming and terrain navigation applications, which demonstrate the utility and capability of the interface.

1.1: In discussion of OpenGL implementation the “[α]view = T-1 • α •T ” included an implicit scale factor. For clarity I replaced this with “[α]view = S-1•T-1 • α •T•S ” in order to make the scale factor’s necessity clearer. ACM COPYRIGHT NOTICE. Copyright © 1999 by the Association for Computing Machinery, Inc. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is

Navigation and interaction in virtual environments that use stereoscopic head-tracked displays and have very large data sets present several challenges beyond those encountered with smaller data sets and simpler displays. First, zooming by approaching or retreating from a target must be augmented by integrating scale as a seventh degree of freedom. Second, in order to maintain good stereoscopic imagery, the interface must: maintain stereo image pairs that the user perceives as a single 3D image, minimize loss of perceived depth since stereoscopic imagery cannot properly occlude the screen's frame, provide maximum depth information, and place objects at distances where they are best manipulated. Finally, the navigation interface must work when the environment is displayed at any scale. This paper addresses these problems for god's-eye-view or third person navigation of a specific large-scale virtual environment: a high-resolution terrain database covering an entire planet.

In this paper we describe a battlefield visualization system, called Dragon, which we have implemented on a virtual reality responsive workbench. The Dragon system has been successfully deployed as part of two large military exercises: the Hunter Warrior advanced warfighting experiment, in March 1997, and the Joint Counter Mine advanced concept tactical demonstration, in August and September 1997. We describe battlefield visualization, the Dragon system, and the workbench, and we describe our experiences as part of these two real-world deployments, with an emphasis on lessons learned and needed future work.