Browsing by Author "McGee, Michael K."
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- Assessing Negative Side Effects in Virtual EnvironmentsMcGee, Michael K. (Virginia Tech, 1998-01-26)Virtual environment (VE) systems have been touted as exciting new technologies with many varied applications. Today VEs are used in telerobotics, training, simulation, medicine, architecture, and entertainment. The future use of VEs seems limited only by the creativity of its designers. However, as with any developing technology, some difficulties need to be overcome. Certain users of VEs experience negative side effects from being immersed into the graphically rendered virtual worlds. Some side effects that have been observed include: disorientation, headaches, and difficulties with vision. These negative side effects threaten the safety and effectiveness of VE systems. Negative side effects have been found to develop in a variety of environments. The research focus on VE side effects thus far has been on the symptoms and not the causes. The main goals of this research is fourfold: 1) to compare a new measure for side effects with established ones; 2) begin analyzing the causes of side effects with an analysis of head-tracking; 3) to examine any adaptation that may occur within a session and between days of a session; and, 4) to examine possible predictors for users who may experience side effects. An experiment was conducted using two different VEs with either head-tracking on or head-tracking off over four days. A questionnaire, a balance test, a vision test, and magnitude estimations of side effects were used to assess the incidence and severity of sickness experienced in the VEs. Other assessments, including a mental rotation test, perceptual style, and a questionnaire on pre-existing susceptibility to motion sickness were administered. All factors were analyzed to determine what their relationships were with the incidence and severity of negative side effects that result from immersion into the VEs. Results showed that head-tracking induces more negative side effects than no head-tracking. The maze task environment induces more negative side effects than the office task environment. Adaptation did not occur from day to day throughout the four testing sessions. The incidence and severity of negative side effects increased at a constant rate throughout the 30 minute immersive VE sessions, but did not show any significant changes from day to day. No evidence was found for a predictor that would foretell who might be susceptible to motion sickness in VEs.
- Integral Perception in Augmented RealityMcGee, Michael K. (Virginia Tech, 1999-09-24)Augmented reality, the superimposing of graphics or text onto an actual visual scene, is intended to enhance a user's understanding of the real world. This research examines the perceptual, cognitive, and human factors implications of combining integrally designed computer-generated imagery with real world scenes. Three experiments were conducted to test the theoretical and practical consequences of integral perception in augmented reality. The first experiment was a psychophysical study that had participants subjectively assess the integrality of 32 scenes comprising four different augmented reality object environments (computer, brain, text, and liquid dynamic model), projected at two transparency levels (opaque, and semi-transparent), and presented with four different graphic textures (color, grayscale, white, and wireframe). The second experiment expanded the psychophysical integrality assessment of augmented scenes to 32 different images composed of four new environments (housing development, computer lab, planetary photo, and trees in countryside), with multiple computer-generated graphics (two, four, six, and eight), at two levels of integrality as defined by experiment one (high, low). The third experiment was an applied study that had two phases: 1) learning tasks using three augmented environments; and, 2) assembly tasks using eight augmented video instructions. The computer-generated graphics for each phase of experiment three were presented at two levels of integrality (high, low) as defined by experiment one. The primary results of the three experiments show that augmented reality scenes with computer-generated imagery presented transparently and in color were perceived most integrally; increasing the number of graphics from two to eight decreased integral perception; and, high integral graphics aided performance in learning and real assembly tasks. From the statistical results and experimenter observation of the three experiments, guidelines for designing integrally perceived graphics in augmented environments were compiled based on principles of human factors, perception, and graphic design. The key themes of the design guidelines were: 1) maintaining true shape information in the computer-generated graphics 2) using highly realistic graphics for naturalistic augmented settings; 3) considering the hardware limitations of the augmented system, particularly the display; and, 4) designing appropriately for the task (simple, complex, hands-on, cognitive, dynamic, static, etc.).