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Principal Investigators
Stephen R. Ellis, Bernard D. Adelstein
Problem and Technical Challenges
Though expensive, high performance head mounted displays have been used as formats for aircraft simulators, FLIR displays, and head-mounted sights for over a decade, the application of lower performance, cheaper versions of these displays to a wide variety of novel civilian and military applications has been constrained by their poorer image quality and the slower dynamics of their associated computer-graphics simulations. Thus, the applications of "virtual reality" and associated displays have remained "just around the corner" and a kind of "demo" technology good for television news clips, but not often for practical work.
Objectives
The general objectives of the research is to focus on specific physical characteristics of the head-mounted display human interface and to study how improvement in scientific knowledge of this and its engineering design can make these displays practically useful. In particular, the characteristics of virtual objects displayed within arms reach on see-though displays will be investigated. Most previous implementations of head-mounted information displays have been used to display much more distant objects.
Approach
A head-mounted "electronic haploscope" has been developed which allows flexible but precise investigation of the physical characteristics of the binocular stimulus presented by nearby computer generated "virtual objects." It is used to study the scientific and engineering issues that affect the accuracy of the presented depth as well as the ability of users to manipulate virtual objects for extended periods without fatigue.
Accomplishments
The principle accomplishments of the head-mounted see-through display task in the last year have been 1) the completion of four experiments examining the cause of errors in depth judgments to virtual targets; 2) The completion of two experiments examining the consequences of monocular, biocular, or stereoscopic viewing on the accuracy of depth judgments of virtual objects. Subjective viewing discomfort while using the displays was also studied; 3) The reduction of measured full system rendering delay for the presentation of head-stabilized, stereoscopic virtual objects from 65 msec to 30 msec and corresponding trebling of average rendering update rate to 60 Hz. 4) The coordination of future research topics with likely needs of industrial and scientific users of head-mounted information displays. In particular, researchers have kept in close contact with Boeing Computer Services and other associated with the Wearable Computer Systems with Transparent, Headmounted Display TRP which involves the development of head-mounted displays for wearable computers. Experimental and engineering results have reported in refereed proceedings papers and are under consideration for publication in refereed journals.
Future Plans
Future work will involve the incorporation of predictive filters into our display system. These filters which are currently undergoing numerical testing will additionally help reduce display latency. The practical benefits of this reduction for improved motion parallax and virtual object manipulation will be tested. These results will be shared with interested parties at Boeing Computer Services, McDonnell- Douglas, and the Johnson Space Center group working on the Virtual Environment Research Facility for the NeuroLab Shuttle mission. New work on extending the total field of view though partial binocular overlap will be initiated.
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