Benjamin Watson

Virtual reality exposure therapy in the treatment of fear of flying: a case report

The efficacy of virtual reality (VR) exposure therapy was examined for the fear of flying. Virtual reality exposure involved six sessions of graded exposure to flying in a virtual airplane. The specific contribution of anxiety management techniques (AMT) and the VR exposure was examined in a single case design. The subject was a 42-year-old female with a debilitating fear and avoidance of flying. All self-report measures of the fear and avoidance of flying decreased following AMT and decreased still further following VR exposure. A planned post-treatment flight was completed with anxiety measures indicating comfortable flight. The implications of this new medium for exposure therapy are discussed.

Measuring and predicting visual fidelity

This paper is a study of techniques for measuring and predicting visual fidelity. As visual stimuli we use polygonal models, and vary their fidelity with two different model simplification algorithms. We also group the stimuli into two object types: animals and man made artifacts. We examine three different experimental techniques for measuring these fidelity changes: naming times, ratings, and preferences. All the measures were sensitive to the type of simplification and level of simplification. However, the measures differed from one another in their response to object type. We also examine several automatic techniques for predicting these experimental measures, including techniques based on images and on the models themselves. Automatic measures of fidelity were successful at predicting experimental ratings, less successful at predicting preferences, and largely failures at predicting naming times. We conclude with suggestions for use and improvement of the experimental and automatic measures of visual fidelity.

On tangible user interfaces, humans and spatiality

Like the prehistoric twig and stone, tangible user interfaces (TUIs) are objects manipulated by humans. Tangible user interface success will depend on how well they exploit spatiality, the intuitive spatial skills humans have with the objects they use. In this paper, we carefully examine the relationship between humans and physical objects, and related previous research. From this examination, we distill a set of observations and turn these into heuristics for incorporation of spatiality into TUI application design, a cornerstone for their success. Following this line of thought, we identify “spatial TUIs,” the subset of TUIs that mediate interaction with shape, space and structure. We then examine several existing spatial TUIs using our heuristics.

Managing level of detail through peripheral degradation: effects on search performance with a head-mounted display

Two user studies were performed to evaluate the effect of level-of-detail (LOD) degradation in the periphery of head-mounted displays on visual search performance. In the first study, spatial detail was degraded by reducing resolution. In the second study, detail was degraded in the color domain by using grayscale in the periphery. In each study, 10 subjects were given a complex search task that required users to indicate whether or not a target object was present among distracters. Subjects used several different displays varying in the amount of detail presented. Frame rate, object location, subject input method, and order of display use were all controlled. The primary dependent measures were search time on correctly performed trials and the percentage of all trials correctly performed. Results indicated that peripheral LOD degradation can be used to reduce color or spatial visual complexity by almost half in some search tasks with out significantly reducing performance.

Modelling the Appearance and Behaviour of Urban Spaces

Urban spaces consist of a complex collection of buildings, parcels, blocks and neighbourhoods interconnected by streets. Accurately modelling both the appearance and the behaviour of dense urban spaces is a significant challenge. The recent surge in urban data and its availability via the Internet has fomented a significant amount of research in computer graphics and in a number of applications in urban planning, emergency management and visualization. In this paper, we seek to provide an overview of methods spanning computer graphics and related fields involved in this goal. Our paper reports the most prominent methods in urban modelling and rendering, urban visualization and urban simulation models. A reader will be well versed in the key problems and current solution methods.

Using texture maps to correct for optical distortion in head-mounted displays

This paper describes a fast method of correcting for optical distortion in head-mounted displays (HMDs). Since the distorted display surface in an HMD is not rectilinear, the shape and location of the graphics window used with the display must be chosen carefully, and some corrections made to the predistortion model. A distortion correction might be performed with optics that reverse the distortion caused by HMD lenses, but such optics can be expensive and offer a correction for only one specific HMD. Integer incremental methods or a lookup table might be used to calculate the correction, but an I/O bottleneck makes this impractical in software. Instead, a texture map may be defined that approximates the required optical correction. Recent equipment advances allow undistorted images to be input into texture mapping hardware at interactive rates. Built in filtering handles predistortion aliasing artifacts.

Cognitive cubes: a tangible user interface for cognitive assessment

Assessments of spatial, constructional ability are used widely in cognitive research and in clinical diagnosis of disease or injury. Some believe that three-dimensional (3D) forms of these assessments would be particularly sensitive, but difficulties with consistency in administration and scoring have limited their use. We describe Cognitive Cubes, a novel computerized tool for 3D constructional assessment that increases consistency and promises improvements in flexibility, reliability, sensitivity and control. Cognitive Cubes makes use of ActiveCube, a novel tangible user interface for describing 3D shape. In testing, Cognitive Cubes was sensitive to differences in cognitive ability and task, and correlated well to a standard paper-and-pencil 3D spatial assessment

Effects of Variation in System Responsiveness on User Performance in Virtual Environments

System responsiveness (SR) is defined as the elapsed time until a system responds to user control. SR fluctuates over time, so it must be described statistically with mean (MSR) and standard deviation (SDSR). In this paper, we examine SR in virtual environments (VEs), outlining its components and methods of experimental measurement and manipulation. Three studies of MSR and SDSR effects on performance of grasp and placement tasks are then presented. The studies used within-subjects designs with 11, 12, and 10 participants, respectively. Results showed that SDSR affected performance only if it was above 82 ms. Placement required more frequent visual feedback and was more sensitive to SR. We infer that VE designers need not tightly control SDSR and may wish to vary SR control based on required visual feedback frequency. These results may be used to improve the human-computer interface in a wide range of interactive graphical applications, including scientific visualization, training, mental health, and entertainment.

A virtual airplane for fear of flying therapy

Fear of flying is a serious problem that affects millions of individuals. Exposure therapy for fear of flying is an effective therapy technique. However, exposure therapy is also expensive, logistically difficult to arrange, and presents significant problems of patient confidentiality and potential embarrassment. We have developed a virtual airplane for use in fear of flying therapy. Using the virtual airplane for exposure therapy is a potential solution to many of the current problems of fear of flying exposure therapy. We describe the design of the virtual airplane and present a case report on its use for fear of flying exposure therapy.

GeneaQuilts: A System for Exploring Large Genealogies

GeneaQuilts is a new visualization technique for representing large genealogies of up to several thousand individuals. The visualization takes the form of a diagonally-filled matrix, where rows are individuals and columns are nuclear families. After identifying the major tasks performed in genealogical research and the limits of current software, we present an interactive genealogy exploration system based on GeneaQuilts. The system includes an overview, a timeline, search and filtering components, and a new interaction technique called Bring & Slide that allows fluid navigation in very large genealogies. We report on preliminary feedback from domain experts and show how our system supports a number of their tasks.