Volumetric Displays

characteristics

light scatters from X, Y, and Z
characterized by "slice-stacking" or "space-filling"
real 3D image (if integrated over time, ~20 ms):
- "...have depth rather than depth cues...." - Sher in McAllister
- full parallax (generally, with extremely wide field of view), accommodation, convergence, but no occlusion
- conceptually: points in XYZ or stack of slices

images are translucent, self-transparent --> no occlusion
brightness decreases with number of imaged points --> low resolutions, shading is difficult
requires high bandwidth - number of points, mechanical speeds, phosphor speeds --> flicker
example: 1024 x 1024 x 100 (in depth) x 30 Hz = 3 Gvoxels/second

Vannavar Bush and Doc Edgerton, c. 1950 - strobe images on spinning surface
multiple CRTs stacked using half-silvered mirrors
cathode ray tube with moving phosphor screen, 1964, R. Ketchpel
Traub 1965 at Mitre - varifocal mirror
two-photon excitation in Hg vapor or ICl; 1970-5, Battelle Labs. 150 pts, 1000 pts possible; related patent
spinning glass plate with steps in thickness, 1976 - W. Chase at NASA
two hinged mirrors - Gerry Marks
Sher at BBN (c.1980) - Space Graph[tm] varifocal mirror: 500 points; 5000 points by 1981 (see Plate 11.1 in McAllister)
Synthalyzer - Roger deMontebello
"xyz scope" c. 1980 - rotating lens. distortions; related patent
spinning emissive panel, c. 1980 - Jannson et al, MIT
spinning helices 1983 to present - Un. of Stuttgart; TI OmniView[tm] very large, colorful, and loud, 10000 voxels; Kodak used CRT; Die Muehle multi-color lasers; NOSC;
spinning projected images, like cathode-ray projector - LAMBDA; ACT Research (MIT spin-off)
physical voxels at UT 1995 - no moving parts

moving mirrors:
- mirror type: flat; membrane or plate
- non-rectangular image volume
- loud!
software processing: display lists; 3D line-drawing and shading (hard)
laser scanner(s) vs. CRT(s): lasers provide dynamic resolution; CRTs are less expensive and higher resolution
parallelism? to overcome bandwidth limitation

psychophysics and human factors, Getty and Huggins in 1986: better than stereo pair
fiber bundle display: patent
patent for something(?) 3D
physical 3D: levitation of tiny spheres (ITT c. 1980); stereolithography
information theoretical point of view: info goes to XYZ and brightness, but NONE goes to directionality --> no occlusion, specular highlights, or other directionally dependent depth cues

(The reading list has more info.)

Two-photon excitation at Stanford - old technique, but lately hyped

NEOS - conceptualizing?

varifocal mirror - from the glory days