Head-Tracked Head-Tracked Displays (HTDs)Displays (HTDs)
Sherman and Craig, pp. 140-Sherman and Craig, pp. 140-151151
Head-tracked DisplaysHead-tracked Displays
Displays in which the user’s head is Displays in which the user’s head is tracked and the image display tracked and the image display screen is located at a fixed location screen is located at a fixed location in physical space.in physical space.
Examples?Examples? CRTCRT Virtual Workbench or ImmersaDeskVirtual Workbench or ImmersaDesk CAVECAVE Many large screen displaysMany large screen displays
CRT HTD (Fishtank VR)CRT HTD (Fishtank VR)
3D Glasses
Head Tracker
Stationary Display
Stereoscopic DisplayStereoscopic Display
User
C
AB
Screen
C
A
B
Standard Display Stereoscopic Display
Virtual WorkbenchVirtual Workbench3D Glasses
3D Display
3D Object
CAVECAVE
Any Projected Large Stereoscopic Any Projected Large Stereoscopic ScreenScreen
CharacteristicsCharacteristics
LargeLarge Projection-Based (except for Projection-Based (except for
Fishtank VR)Fishtank VR) StereoscopicStereoscopic Head TrackedHead Tracked Stationary Display Screen(s)Stationary Display Screen(s) Let’s try to identify the pros and Let’s try to identify the pros and
cons and application domainscons and application domains
3D Glasses
3D Display
3D Object
Large Screen ProjectionLarge Screen Projection
Larger field-of-Larger field-of-view than HMDview than HMD
Field of regard is Field of regard is smaller than HMD smaller than HMD but larger than a but larger than a typical CRT typical CRT DisplayDisplay
Projectors must be Projectors must be aligned properly.aligned properly.
Architectural Architectural Statement!Statement! Front Projection (user Front Projection (user
may be in the way).may be in the way). Back Projection (takes Back Projection (takes
up even more space)up even more space) When multiple When multiple
screens are arranged screens are arranged at or near 90 degree at or near 90 degree angles, reflection angles, reflection between screens may between screens may be a problembe a problem
Large Screen ProjectionLarge Screen Projection
AdvantagesAdvantages Viewer not isolated from Viewer not isolated from
real objects or other real objects or other people in the virtual people in the virtual world space.world space.
Less physical gear to Less physical gear to wear than HMDwear than HMD
Potentially better Potentially better resolution than HMDresolution than HMD
Large field of view Large field of view compared to HMD or compared to HMD or CRT.CRT.
DisadvantageDisadvantagess Usually one one person Usually one one person
is head-tracked.is head-tracked. Real objects may occlude Real objects may occlude
virtual objects in virtual objects in inappropriate waysinappropriate ways
Multiple screens require Multiple screens require more computationmore computation
At least one direction is At least one direction is not part of the virtual not part of the virtual world.world.
LightingLighting