Combining Head-Mounted and Projector-Based Displays for Surgical Training

We introduce and present preliminary results for a hybrid display system combining head-mounted and projector-based displays. Our work is motivated by a surgical training application, where it is necessary to simultaneously provide both a high-fidelity view of a central close-up task (the surgery) and visual awareness of objects and events in the surrounding environment. In particular, for trauma surgeons it would be valuable to learn to work in an environment that is realistically filled with both necessary and distracting objects and events

An Evaluation of Level of Detail Degradation in Head-Mounted Display Peripheries

A paradigm for the design of systems that manage level of detail in virtual environments is proposed. As an example of the prototyping step in this paradigm, a user study was performed to evaluate the effectiveness of high detail insets used with head-mounted displays. Ten subjects were given a simple search task that required the location and identification of a single target object. All subjects used seven different displays (the independent variable), varying in inset size and peripheral detail, to perform this task. Frame rate, target location, subject input method, and order of display use were all controlled. Primary dependent measures were search time on trials with correct identification, and the percentage of all trials correctly identified. ANOVAs of the results showed that insetless, high detail displays did not lead to significantly different search times or accuracies than displays with insets. In fact, only the insetless, low detail display returned significantl..

An Investigation Of The Relationship Between Visual Effects And Object Identification Using Eye-tracking

The visual content represented on information displays used in training environments prescribe display attributes as brightness, color, contrast, and motion blur, but considerations regarding cognitive processes corresponding to these visual features require further attention in order to optimize the display for training applications. This dissertation describes an empirical study with which information display features, specifically color and motion blur reduction, were investigated to assess their impact in a training scenario involving visual search and threat detection. Presented in this document is a review of the theory and literature describing display technology, its applications to training, and how eye-tracking systems can be used to objectively measure cognitive activity. The experiment required participants to complete a threat identification task, while altering the displays settings beforehand, to assess the utility of the display capabilities. The data obtained led to the conclusion that motion blur had a stronger impact on perceptual load than the addition of color. The increased perceptual load resulted in approximately 8- 10% longer fixation durations for all display conditions and a similar decrease in the number of saccades, but only when motion blur reduction was used. No differences were found in terms of threat location or threat identification accuracy, so it was concluded that the effects of perceptual load were independent of germane cognitive load

Affordances In The Design Of Virtual Environments

Human-computer interaction design principles largely focus on static representations and have yet to fully incorporate theories of perception appropriate for the dynamic multimodal interactions inherent to virtual environment (VE) interaction. Theories of direct perception, in particular affordance theory, may prove particularly relevant to enhancing VE interaction design. The present research constructs a conceptual model of how affordances are realized in the natural world and how lack of sensory stimuli may lead to realization failures in virtual environments. Implications of the model were empirically investigated by examining three affordances: passability, catchability, and flyability. The experimental design involved four factors for each of the three affordances and was implemented as a 2 [subscript IV] [superscript 4-1] fractional factorial design. The results demonstrated that providing affording cues led to behavior closely in-line with real-world behavior. More specifically, when given affording cues participants tended to rotate their virtual bodies when entering narrow passageways, accurately judge balls as catchable, and fly when conditions warranted it. The results support the conceptual model and demonstrate 1) that substituting designed cues via sensory stimuli in available sensory modalities for absent or impoverished modalities may enable the perception of affordances in VEs; 2) that sensory stimuli substitutions provide potential approaches for enabling the perception of affordances in a VE which in the real world are cross-modal; and 3) that affordances relating to specific action capabilities may be enabled by designed sensory stimuli. This research lays an empirical foundation for a science of VE design based on choosing and implementing design properties so as to evoke targeted user behavio

Methodology for assessment of cognitive skills in virtual environments

The client briefing of the proposed building design is usually in the form of drawingsand artistic impressions being presented to the client. However, very few clients areable to read a technical drawing and the artist impressions are limited and do not aidthe client to visualise all aspects of the proposed building. During the client briefingprocess the client needs to have the experiential quality described, to be able to fullyunderstand the design of the proposed building. Generally, humans perceive anddirectly experience architectural space by building qualities like texture, form, colour,light, scale, movement. A full-scale model of the proposed building would fullyafford the experimental qualities. In reality it would be impractical and not costeffective. However, VR technology allows the creation of an inclusion of space inuser's mind, through a minimum of means, but achieves a maximum impact, andaffords all the experiential qualities offered by a physical model.A virtual model with a high degree of detail which can be explored by the designerand his clients will therefore be of significant help. However, to give clients the bestpossible impression of the proposed design it is important to understand howdimensions of those designed spaces are perceived. Therefore, a study was carried outfocusing on fundamental investigations into the perception of basic architecturaldimensions in order to assess the potential usefulness of VR technology inarchitecture and the client briefing process. In two experiments, subjects were required to estimate egocentric and exocentricdimensions in Virtual Environments and Real World Setting (RWS). The influence ofstimuli orientation was also investigated. In estimating all dimensions a magnitudeestimation procedure was employed using a modified free-modulus technique. Allparticipants were pre-tested. Psychometric and visual tests were used for choosing anexperimental group with a fair degree of homogenity. Two independent subject groupswere used. In addition to dimension estimations recall of simple layout and feeling ofspace were investigated when evaluating the virtual interface.The general null hypothesis assumed that people perceive space in VE as well as inthe real world. It has been shown that the results are statistically significant andtherefore one was able to reject the general hypothesis. Overall participantsunderestimated the dimensions in both experiments by approximately 20%. Resultsand limitations of the study are discussed. The results of the experiments wouldindicate that VR technology can be used for simulations of architectural spacesbecause despite underestimations of dimensions it still performed relatively well ifone compares it with results of experiments in the Real World Settings