Michael Naimark
michael@naimark.net
ABSTRACT
A
novel enclosure is integrated around a flat panel video display. The enclosure has a
ÒwindowÓ in front fitted with a flat magnifying element such as a
Fresnel lens to create (or suggest) an infinity-focus effect. The enclosure
also has sides that isolate and ventilate the air inside to eliminate heat from
the display and to provide climate control for the viewers. The enclosed
display may serve as a module that can be displayed together with other modules
as a larger, orthoscopically correct, immersive display (and one where a larger, magnified image and drastically reduced mullions are "free"). A more advanced embodiment
additionally integrates stereoscopic 3D, both for far-field 2D imagery and for
mixed near-field and far-field stereoscopic imagery.
1.
Introduction
(Interval Research Corporation, UNESCO World Heritage
Centre, photo: Theo Westenberger)
Making a Òfar-fieldÓ display
for viewing landscapes may therefore engage these three elements: orthoscopic
correctness, Òinfinity focusÓ accommodation, and Òzero convergenceÓ
stereoscopic 3D with identical images seen by both eyes. Our eyes (and
therefore our selves) feel it when these elements are properly engaged. But anecdotal
experience suggests that each have a degree of tolerance or Òwiggle roomÓ.
1.1.1
Orthoscopic Correctness
ÒKarlsruhe
MoviemapÓ, interactive art
installation, Siggraph 1991, Las Vegas
(ZKM Centre for Arts and Media)
The ÒKalrsruhe Moviemap,Ó an
interactive art installation filmed from a tram, was shot with a wide-angle
lens with a horizontal field of view (FOV) just under 90 degrees. The user interaction
occurred from a platform with a lever and foot switches, as well as an overview
Òyou-are-hereÓ map display, which could be placed in front of the screen to
replicate the orthoscopically correct FOV. But it was found that Òhaving it
roughly closeÓ was good enough. For example, as shown at Siggraph 1991, the
horizontal FOV approximated 60 degrees rather than 90 degrees, but given that
the display still appeared Òbigger than normal,Ó the suggestion of orthoscopic
correctness was convincing.
Karlsruhe Moviemap displayed
through an infinity focus ÒwindowÓ (behind a map display and control unit),
Exploratorium 1992, San
Francisco
The Karslruhe
Moviemap was often exhibited with the display approximately 20 feet away from
the input platform, enough for the viewers' eyes to accommodate close to infinity. But
it was exhibited at the Exploratorium in 1992 using a consumer sized
rear-projection television behind a wall with a rectangular window cut out of
it. The window was fitted with a flat lenticular magnifying lens. The television was
less than 12 inches behind the lens which not only magnified but altered the
accomodation of viewersÕ eyes to appear close to infinity. This could be
confirmed by placing a camera with a calibrated manual focusing lens where
viewers stand, focusing on the television, then reading the lens setting.
Viewers stood
directly in front of the window, usually no more than one or two feet away.
Even though their eyes were converging rather than parallel, the Òinfinity
focusÓ effect was prominent. Several viewers asked if it was a ÒholographicÓ
display.
The use of
magnifiying optics naturally increases the image size but also Òre-placesÓ the
image to appear further away, in terms of accommodation. Before the advent of
large flat magnifiying lenses such as Fresnels, the flight simulator industry
sometimes used a concave mirror to achieve the same effect.
Additionally,
placing the display behind a wall may mask the edges of the display and, by
having the screen seen in direct comparison with something closer (the wall),
enhances the illusion that it is Òfurther back.Ó Special effects producer
Douglas Trumbull used this Òfurther backÓ effect by building overhanging frames
in front of his special-venue 70mm ÒShowscanÓ theater screens.
1.1.3 ÒZero convergenceÓ stereoscopic 3D
Timbuktu, from Be Now Here,
Yerba Buena Center for the Arts, San Francisco, 1995
ÒBe Now HereÓ, a
stereo-panoramic art installation, was filmed with a slowly rotating pair of
stereoscopic cameras. The installation consisted of a cylindrical room with a
stereoscopic screen and a slowly rotating floor (in sync with the cameras).
Though much of the imagery included near-field material, such as the boy
pictured above, a considerable amount of the imagery was strictly far-field,
with essentially identical views for both eyes. The left and right views were calibrated to display zero convergence for far-field imagery (by displacing such imagery ~2.5 inches, the average human interocular distance). It
was found that viewers could walk up to the rail, approximately three feet from
the screen, and still feel as though their eyes were gazing far away, even
without proper infinity focus accommodation.
Be Now Here installation at Art
Center College of Design, Pasadena, 2005
Be Now Here consisted of a
relatively small enclosed space, a 16 foot diameter cylindrical room with black
curtains around most of it except for the screen. Its capacity during pubic
exhibitions was generally limited to ten viewers. It was found that the use of
climate control fans made a huge difference for the user experience; without
them the space was uncomfortably hot and stuffy. Enhancing the physiology of
the viewers enhanced their psychology with respect to their experience. 1.3 Modularity –
Practical Immersion
Dubrovnik, from ÒBe Now
Here TriptychÓ, Helen Lindhurst Gallery, USC,
Los Angeles, 2008
(USC
School of Cinematic Arts and Ars Electronica Linz)
Be Now Here, as an art
installation with a cylindrical room and a rotating floor, weighed over 4,000
pounds and required several human-days to install. In 2008, when
stereo3D-capable ÒDLPÓ consumer projection televisions became available, the
same footage was used to make a 180 degree, 3-screen triptych. The use of
modular displays to build a panorama meant that ÒmullionsÓ, the black vertical
spaces between the displays, would be visible. Generally speaking, it was found
that mullions were perceptually inconsequential, while the practicality of a
smaller, modular immersive system made good sense.
This invention integrates a
climate-controlled enclosure around a flat panel video display. The enclosure
has a transparent ÒwindowÓ in front allowing the display to be seen. The window
may be fitted with a flat magnifying element such as a Fresnel or holographic
magnifying lens to create an infinity-focus effect. The enclosure includes
sides that isolate and ventilate the air inside to eliminate heat from the
display. The enclosed display may serve as a module that can be displayed
together as a larger immersive display.
2.1 Far-field Optics
The window of the enclosure may
have a flat magnifying element (i.e., a positive diopter), which both magnifies
and changes the apparent distance focused on the display. Its main purpose is
to let the viewersÕ eyes accommodate at or near infinity even though they are
relatively close to the display itself. As a magnifying element, its secondary
purpose is to make the display look larger than it actually is. Additionally,
the window of the enclosure may include some amount of framing around the front
in such as way as to mask or partially mask the edges of the display, creating
the illusion that the imagery displayed is even further away.
The amount of magnification and
the distance of the magnifying element from the display are variable. The
weaker the magnification and the shorter the distance to the display, the less
the apparent focus will approach infinity but the wider the FOV in the viewing
space in front of the enclosure. The stronger the magnification and the greater
the distance to the display, the more the apparent focus may approach infinity,
within limits, but the narrower the FOV in the viewing space in front of the
enclosure.
A preferred embodiment may use a
relatively medium to strong magnifying element placed a relatively short
distance from the display, to maximize the effect while minimizing the amount
of space used. For a typical flat panel display, e.g., 40 to 60 inch, the
magnification may be 1.5x to 4x and the distance from the magnifying element to
the display may be under 10 or 20 inches. It is not critical that true
Òinfinity focusÓ is achieved as much as is suggested in order to create a rich
immersive experience. Even a little bit helps, in fact, even with no
magnification (1.0x), simply framing the front of the display enhances the
illusion of distance behind.
The magnification element
should be of sufficiently high quality to minimize additional artifacts to the
display. Though it could in theory be a large Òdouble-convexÓ glass element, it
is more practical to use flat magnifying elements, the most common today being
Fresnel lenses. A hologram of a magnifying element may then be used as a
magnifying element, but such holographic elements are currently not practical
on the scale required.
2.2 Climate-Controlled
Enclosure
The enclosure may be made of
climate-isolating material and encloses the display on the front, sides, and
optionally on the back. The front consists mostly of the far-field optical
element and optionally a small frame around the edges. The enclosure allows
climate-controlled air to circulate through enclosed area.
A preferred embodiment may
remove heat from the display by intaking air from below the enclosure and
blowing it out to the rear at the top of the enclosure, using fans. The bottom
of the enclosure and the top rear of the enclosure may be completely open. A
more elaborate climate controller may be integral or a separated unit via known
means such as vent, baffles, and ducts. It may be a simple fan or an actual air
conditioner unit. The wider the volume of air circulation, the less noise.
The climate-controlled
enclosure may also be used to affect the climate outside of the enclosure, in
particular, of the viewers standing in front. For example, the temperature
experienced by the viewers may be programmed to maintain reasonable comfort
levels. Additionally, this temperature (and even humidity and scent through
known means) may be synchronized with the imagery viewed. Output vents for may
be above or below the display, or may be built into the vertical mullions.
2.3 Modular Design
The climate-controlled
enclosure around a video display with far-field optics in front is designed to
be modular and used in arrays, particularly in horizontal arrays approximating
a cylinder for panoramic imagery. These modules may be only a few inches deeper
than the display itself (to allow for magnification), a few inches higher than
the display itself (for the ventilation intake and exhaust), and no wider than
the optical element. Since the optical element magnifies, the display may be smaller
than the optical element and the sides of the module may flange forward.
The climate control for each
module may be independent or modules may be interconnected and share the same
climate controller such as an external air conditioner, through known means of
ducts and hoses. Additionally, the modules may be physically interconnected
through known means of rapid attachment and detachment for fast and simple
assembly and disassembly with proper registration among the displays.
Anecdotal evidence suggests
that adding infinity focus and adding zero convergence stereoscopic 3D may both
individually enhance the far-field viewing experience. Since stereoscopic 3D
generally requires glasses (always true for more than one viewer), the preferred
embodiment described above has the greatest enhancement at the smallest cost
and effort by viewers. But a ÒdeluxeÓ model, incorporating both infinity focus
and stereoscopic 3D, is worth considering for an ultimate immersive viewing experience.
A preferred embodiment of such
a system may use inexpensive ÒactiveÓ (LCD shutter) glasses and flat video
displays capable of high frame rates, such as current 120 Hz ÒDLPÓ projection
televisions. The far-field imagery, naturally 2D, may be digitally displaced horizontally
for left and right eyes by the average human interocular distance (~2.5
inches), such that the viewersÕ eyes gaze in parallel with zero convergence.
Assuming that all of the imagery is far-field, e.g., Òlandscape,Ó no special 3D
recording is required.
Such a system may also display
mixed near-field and far-field imagery with little compromise. One minor
modification may be to decrease the infinity focus of the magnifying element,
e.g., from infinity to 8 or 10 feet, to help accommodate both near and far-field
imagery. This display system may then be capable of showing stereoscopically recorded
imagery as well as 2D recorded far-field landscapes.
(Interval Research Corporation, Banff Centre for the Arts,
photo: Louie Psihoyos)
Be Now
Here Triptych http://www.naimark.net/projects/bnh3.html
Be Now
Here http://www.naimark.net/projects/benowhere.html
See
Banff kinetoscope http://www.naimark.net/projects/banff.html Karlsruhe
Moviemap http://www.naimark.net/projects/karlsruhe.html
"Two Unusual Projection Spaces," Presence, Special Issue on Projection, MIT Press, 14.5,
October 2005 |
