Origins of Virtual Environments

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Origins of Virtual Environments. S.R. Ellis, Origins and Elements of Virtual Environments, in Virtual Environments and Advanced Interface Design , Barfield and Furness, Oxford University Press, 1995, pp. 14-57 Summarized by Geb Thomas. Learning Objectives. - PowerPoint PPT Presentation

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<ul><li><p>Origins of Virtual EnvironmentsS.R. Ellis, Origins and Elements of Virtual Environments, in Virtual Environments and Advanced Interface Design, Barfield and Furness, Oxford University Press, 1995, pp. 14-57</p><p>Summarized by Geb Thomas</p></li><li><p>Learning Objectives1. Learn what VR is and how it works as a form of communication. 2. Understand the concept of virtualization including the differences between virtual space, a virtual image and a virtual environment. 3. Learn about the history of virtual environments and the important pioneers and forces that shaped its creation. 4. Understand the variety and types of hardware used in VR. 5. Learn about the types of tradeoffs that VR technology requires, particularly cost versus performance, mass of gear to be worn, and resolution versus field of view. </p></li><li><p>Communications and EnvironmentsVEs are media, like books, movies or radioTask of scientists is to make interaction with the media efficient and effortless -- reduce the adaptation periodVE extends the desktop metaphor to 3D.Historically this uses physical constraints from simulator and telerobotics fields</p></li><li><p>Components of VEContent</p><p>Geometry </p><p>Dynamics</p></li><li><p>ContentObjects and actors described by characteristic vectors (a total description of each element) and position vectors (a subset of character vectors).</p><p>Self is a special actor representing point of view</p></li><li><p>GeometryDimensionalityNumber of independent descriptive terms needd to specify the position vectorMetricsRules applied to the position vector to establish orderExtentThe range of possible values for the position vector</p></li><li><p>DynamicsRules of interaction of the content elements</p><p>Example, the differential equations of Newtonian dynamics.</p></li><li><p>Our Sense of Physical RealityWe construct reality from symbolic, geometric and dynamic information directly presented to our sensesGenerally we see only a small part of the whole.We rely on a priori knowledgeWe are predisposed to certain arrangements of information -- we resonate with some more than others.</p></li><li><p>VirtualizationThe process by which a human viewer interprets a patterned sensory impression to represent an extended object in a n environment other than that in which it physically exists.Three levels:Virtual spaceVirtual imageVirtual Environment</p></li><li><p>Virtual SpacePerceived 3D layout of objects in space when viewing a flat screenperspectiveshadingocclusiontexture gradientsThis must be learned! False cuesPerceived size or scale is not inherent in media</p></li><li><p>Virtual ImageThe perception of an object in depth with accommodative, vergence and (optionally) stereoscopic disparity cues are present.Scale not arbitrary</p></li><li><p>Virtual EnvironmentAdd observer-slaved motion parallax, depth of focus variation and wide field-of-view without visible restriction of the field of viewvergenceaccommodative vergence - reflective change in vergence caused by focus adjust.optokinetic reflex - eye tracking objectsvestibular-ocular reflex - eye tracking head</p></li><li><p>Virtual Environments (cont)Measurements of the degree to which a VE display convinces its users that they are present in the synthetic world can be made by measuring the degree to which these responses can be triggered in it.Device calibration and timing are critical. The sensory systems can often adjust to systematic distortion, but not to time lags.</p></li><li><p>ViewpointsEgocentric -- see the world from viewers point of viewExocentric -- see the user acting in the worldSimilar to inside-out and outside-in frames in aviation literature</p></li><li><p>Origins of VEHuman fascination with vicarious experiencecave artThrough the looking glassComputer gamesNeuromancer (Gibson)Ivan Sutherland stereo displayMyron Kruegers VIDEOPLACEU. of Illinois CAVE</p></li><li><p>Vehicle SimulationMuch VE derived from aircraft and ship simulatorsDevelopment of special purpose machines: matrix multipliers -- graphic pipelines, graphic engines</p></li><li><p>Moving SimulatorsMotion sicknessSubthreshold visual-vestibular mismatches to produce illusions of greater freedom of movement washoutUnderstand dynamic limits of visual-vestibular miscorrelation</p></li><li><p>CartographyControlled information distortionspherical projectionvertical scale exaggerationVEs can enhance presentation with graticules to help avoid effects of distortion.Combine images to make virtual maps</p></li><li><p>ApplicationsScientific and medical visualizationmultiple time functions of force and torque on manipulator or limb jointsVolumetric medical dataElectronic dissectionArchitectural Walk-throughs</p></li><li><p>TeleroboticsPredated many VR technologySpurred position tracking technologyPolhemus systemaccelerometersoptical trackingacoustic systemsmechanical systems</p></li><li><p>Telerobotics IIInput devices Isotonic (significant travel)Isometric (sense force and torque)Force feedback deviceshigh electro-mechanical bandwidthCan create instabilitiesUtah/MIT Hand</p></li><li><p>Photography, cinematography, viceo technologyThe LEEP optical system, originally for stereo video used in VR stereo viewersSensorama, Morton Heilig (1955)Interactive video map (MIT 1980)</p></li><li><p>Engineering ModelsTendency to overplay successes and suggest greater generality than existsMost helmet-mounted displays make users legally blindWe need to understand characteristics ofhuman movementvisual trackingvestibular responsesgraspmanual tracktime lags</p></li><li><p>VE: Performance and Trade-OffsPerformance AdvancesStereoscopic visual strainResolution/field-of-view tradeoffAppropriate application areas:multiple, simultaneous, coordinated, real-time foci of controlManipulation of objects in complex visual environments and require frequent, concurrent changes in viewing position</p></li><li><p>Learning Objectives1. Learn what VR is and how it works as a form of communication. 2. Understand the concept of virtualization including the differences between virtual space, a virtual image and a virtual environment. 3. Learn about the history of virtual environments and the important pioneers and forces that shaped its creation. 4. Understand the variety and types of hardware used in VR. 5. Learn about the types of tradeoffs that VR technology requires, particularly cost versus performance, mass of gear to be worn, and resolution versus field of view. </p></li><li><p>For FridayRead the NRC Report, especially 13-24 and 35-66. Skim the restPersonally, I think the recommendations are very interesting, because they reveal how a panel of scientists think of what research is important. Depending on where you are in your career, however this may not be so key.Start drafting your essay. I want to see complete, supported ideas, not stream-of-consciousness!</p></li></ul>