Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Title: IMMERSIVE EXPERIENCE MOTION PICTURE
THEATRE AND METHOD
FIFL D OF THE INVENTION
This invention relates generally to methods of presenting
motion picture images to audiences in theatres.
BACKGROUND OF THE INVENTION
So-called "immersive experience" motion picture theatres
attempt to provide audience members with the perception that they are
"immersed" in the images that are being shown. Typically, such theatres
are relatively small and are designed to provide an intimate theatre
environment. Often, 3-D motion pictures are shown, sometimes on a
dome screen. Dome screens in particular give audience members the
perception of being "within" the environment represented by the
projected images. Large format dome screen 3-D images such as those that
are shown in IMAX SOLIDO~ theatres, are particularly effective in
providing a realistic immersive theatre experience.
Special techniques are required to produce motion pictures
that satisfactorily can be projected in 3-D on a dome; accordingly,
production costs are high. Considering those costs, and the fact that only a
relatively small number of dome theatres are capable of showing the films,
the selection of available films is relatively restricted.
An object of the present invention is to provide a motion
picture theatre structure and a method of presenting motion picture
images that are capable of providing an immersive motion picture
experience. In particular, the theatre structure and method of the
invention may allow showing in a novel immersive environment, of 3-D
motion pictures that were produced for projection onto conventional flat
screens. In other words, the objective is to achieve a dome-like immersive
experience using motion pictures that were shot for flat screens.
SUMMARY OF THE INVENTION
One aspect of the present invention provides a motion
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picture theatre structure including a screen, an audience seating deck
which slopes downwardly towards the screen, and at least one projector
located within the seating deck for projecting images onto the screen about
an optical projection axis which is angled upwardly with respect to the
horizontal. The screen is arcuate as seen in plan and is positioned
symmetrically with respect to the projection axis of the projector and so as
to wrap around respective sides of the seating deck. The screen also slopes
upwardly towards and extends above the seating deck for providing the
audience with a sense of immersion in images projected onto the screen.
The projector is provided with a wide angle lens with low centre-of-field
distortion, for example an orthographic fisheye lens. An orthographic
fisheye lens can be designed to substantially fill the screen with projected
images, while minimizing distortion of centre regions of the images.
Another aspect of the invention provides a method of
presenting motion picture images to audience, comprising the steps of:
providing: a screen which has an arcuate shape as seen in
plan; an audience seating deck which slopes downwardly towards the
screen; and at least one projector located within the seating deck for
projecting images onto the screen about an optical projection axis which is
angled upwardly with respect to the horizontal;
positioning the screen (a) symmetrically with respect to the
projection axis as seen in plan so that said arcuate shape wraps around
respective sides of the seating deck and (b) sloping towards and extending
above the seating deck, whereby the audience is provided with a sense of
immersion in images projected onto the screen; and,
projecting images onto the screen from said at least one
projector using a wide angle lens with low centre-of-field distortion, for
example an orthographic fisheye lens, for substantially filling the screen
with projected images and providing an immersive viewing experience.
In summary, the present invention provides an immersive
theatre experience in that the screen wraps around and extends above the
seating deck so as to essentially fill the field of view of audience members
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in much the same way as a dome screen, except that the screen does not
extend behind the viewer. At the same time, by using a lens such as an
orthographic fisheye lens on the projector, distortion in the central portion
of the image is minimized and in a sense "pushed out" to the periphery of
the image, where it becomes much less significant in terms of viewer
perception, particularly for 3-D presentations.
Theatres in accordance with the present invention may be
designed as new "immersive experience" theatres or as modifications or
"retrofits" to existing dome theatres. In either event, the resulting theatre
will be capable of showing a. wide range of films irrespective of whether
those films were initially shot for showing in dome theatres or more
conventional flat screen theatres. For example, an IMAX~ theatre in
accordance with the present invention would be capable of showing the
full range of IMAX~ 3-D films whether shot initially for "normal"
IMAX~ or IMAX SOLIDO~ theatres, and whether in 2-D or 3-D format.
BR~,EF DESCRIPTION OF DRAWINGS
In order that the invention may be more clearly understood,
reference will now be made to the accompanying drawings which
illustrate a preferred embodiment of the invention by way of example, and
in which:
Fig. 1 is a perspective view of a theatre structure in accordance
with a preferred embodiment of the invention;
Fig. 2 is a plan view of the theatre structure shown in Fig. 1;
Fig. 3 is a side elevational view;
Fig. 4 is a reproduction of a photograph taken through an
orthographic fisheye lens for the purpose of illustrating the characteristics
of the lens; and,
Fig. 5 is a diagrammatic front elevational view of a projector
for use in the theatre structure of the invention.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring first to Fig. 1, the interior of a theatre is shown as
seen from above and to one side of the rear of a seating deck 20 of the
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theatre, looking towards a curved projection screen 22. Images projected
onto screen 22 are represented at 24 and are projected from a projector 26
located within the seating deck 20. External walls of the theatre are
represented at 28.
Figs. 2 and 3 show schematically, the overall configuration of
the theatre including external walls 28, the seating deck 20, screen 22 and
projector 26. In these views, the theatre is shown "as designed", although
it is to be understood that the theatre structure of the invention could be
achieved by modifying or "retrofitting" an existing theatre, such as a 3-D
dome theatre. In that case, the screen 22 would be assembled inside the
existing building.
Fig. 3 shows that the seating deck 20 slopes downwardly
towards the screen 22 and that the projector 26 projects images onto the
screen 22 about an optical projection axis 30 which is angled upwardly with
respect to the horizontal (32). It will be seen that projector 26 is in fact
located within a projection room 34 that is built into the seating deck amid
upper ones of the rows of seats (see Fig. 3); images are projected through a
window 36 in the projection room.
As best seen in Fig. 1, the screen 22 has an arcuate shape as
seen in plan (see Fig. 2). The projection axis 30 referred to in connection
with Fig. 3 is also indicated in Fig. 2 and it will be seen that the screen 22
is
positioned symmetrically with respect to the projection axis as seen in
plan, and is arranged to "wrap around" respectively opposite sides of the
seating deck 20. From that view and from Fig. 3, it will be seen that the
screen also slopes upwardly towards and extends above the seating deck.
In summary, the screen wraps laterally around and extends above the
seating deck; this provides the audience with a sense of immersion in the
images projected onto the screen.
In this particular embodiment, screen 22 has the shape of a
segment of a cone which tapers towards the upper end of the screen and is
tilted towards the seating deck as described previously to provide the
desired wrap around immersive environment. In order to optimize the
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characteristic of the reflected light, the angle of tilt of the screen is
selected
so that the optical axis of projection 30 meets the screen generally at a
right
angle (~ 10°)on the vertical centreline of the screen C (Fig. 2). In
this case,
the angle of tilt (~ -- Fig. 3) is approximately 15° with respect to
the vertical.
The vertical height of screen 22 (in this embodiment 60 feet)
is selected to match the characteristics of the projection lens L of projector
26 in terms of the vertical extent of the projected image.
Similarly, the lateral extent of screen 22 (see Fig. 2) is selected
to match the horizontal extent of the projected image, which is in this case
about 150°. Compared with a theoretical angle of 180° for a full
dome
screen, it will be seen that there is some loss of extent of the projected
image, though the amount is not believed to be significant in terms of
audience experience since the loss is in the viewer's region of peripheral
vision only.
The projection lens of projector 26 (L -- Figs. 2 and 3) is an
orthographic fisheye lens. Fig. 4 is a representation of a photograph taken
through such a lens and illustrates the fact that distortion in the centre
region of the image is minimized to a greater extent than with a
conventional fisheye lens and is, in effect, "pushed out" towards
peripheral regions of the image. This is evident from Fig. 4 in that the
lines delineating the edges of buildings are straight in centre regions of the
image and curve to progressively greater extents towards the perimeter of
the image. In the application of the present invention, this means that the
projected images tend to be true in front of the viewer and that distortions
occur in the regions of the peripheral vision of the viewer, where they are
much less noticeable. Orthographic lenses are well-known in the art and
have been available from Nikon under the trade mark NIKKORT"'.
Characteristics of orthographic lenses are described in "Applied
Photographic Optics" by Sydney F. Ray first published 1988 by Focal Press --
London and Boston. As described in Ray, an orthographic lens is defined
by the formula
y = 2f sin (e/2) or y = f sin 6
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where f equals focal length, y equals image height, 8 equals semi-object
field angle (rad) in object space.
It should here be noted that, while Fig. 4 is illustrative of an
orthographic fisheye lens, it is not intended to represent the precise
characteristics of an optimum fisheye lens for use in the method of the
present invention.
As indicated previously, the method and theatre structure of
the present invention are applicable to presentation of both 2-D and 3-D
motion pictures. Where 3-D motion pictures are to be projected,
respective sets of "left-eye" and "right-eye" images must be projected and
optically coded, for example, by using mutually extinguishing polarizers or
by projecting the images alternately. The viewers must then wear
eyeglasses designed to decode the images so that the viewer's left eye sees
only left-eye images and the right eye only right-eye images. Both
polarizer and "alternate eye" techniques for effecting such coding and
decoding are well-known in the art. Preferably, the alternate eye technique
is used in the method of the invention.
While two projectors may be used, a single projector for
projecting both sets of images is preferred. For example, a rolling loop
projector of the type shown in United States Patent No. 4,966,454
(Toporkiewicz) may be used. The disclosure of this patent is incorporated
herein by reference. Basically, the projector has two superposed rolling
loop mechanisms, one of which projects the left-eye images while the
other projects the right-eye images. The respective sets of images are
projected through superposed lenses generally as shown in Fig. 5. In that
view, the two rolling loop mechanisms are denoted 46 and 48 and the
respective lenses associated with two mechanisms are denoted 50 and 52.
U.S. Patent No. 4,997,270 (Shaw) which is also incorporated
herein by reference, discloses an arrangement for performing a
programmed "lens shift" to correct for abnormalities in the print from
which the images are being projected. In the method of the present
invention, a similar technique may be used to optimize presentation of
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the projected images, for example to compensate for the fact that the film
may originally have been shot for showing on a flat screen. In such a case,
the position of the center of interest within images will have been chosen
with the geometry of a typical flat screen theatre in mind. Typically, the
centre of interest of these images will appear near the vertical mid-point
on a flat projection screen. In an immersive theatre, such images will
appear too high on the screen for audience seated in the front rows. Thus,
in order to change the vertical position of the image as projected to shift
the centre of interest to co-incide with the best viewing point on the
screen, the two lenses, 50 and 52 may be moved together up or down
through the same incremental amount. Such movement should be
programmed in real time to correspond with scenes in the film being
projected, all generally as described in the Shaw patent supra.
Similarly, the lenses 50 and 52 can be programmed to change
the "parallax" of the image, i.e. to move the image towards or away from
the audience by effecting relative shift of the lenses inwardly or outwardly.
Both lenses may be shifted (both outwardly or both inwardly) or only one
lens may be shifted while the other lens is kept stationary. Again, this lens
shift would be programmed in real time to follow the images on the film.
In Fig. 5, vertical shift of both lenses to change the centre of interest of
the
projected image is represented at 54 and horizontal shift to adjust the
image parallax is represented at 56 as movement of the lower lens 52.
The actual mechanisms by which the lenses are shifted may
be designed in accordance with the teachings of the Shaw patent supra. In
one embodiment, the two lenses are carried on a common carriage 58 that
can be moved vertically by a rotary actuator 60 with respect to a lens
mount M. At the same time, lens 52 is supported on carriage 58 for
horizontal movement under the control of a rotary actuator 62. The two
actuators 60 and 62 are operated by a controller 64 that responds to
"witness" marks on one of the two films via a reader 66.
In summary, the method and structure provided by the
invention allows creation of an immersive motion picture experience by
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means of a theatre structure that is less costly than a conventional dome
theatre but which at the same time produces a very similar motion picture
experience. An existing dome theatre can be converted in accordance with
the invention at relatively low cost by installing a curved screen as screen
22 and providing the projector with an orthographic fisheye lens as
described previously. The theatre can then show a complete range of
motion pictures whether originally shot for dome screens or for
conventional flat screens.
It should be noted that the drawings of the preferred
embodiment included herein illustrate the invention in schematic terms
only and that precise details may vary within the broad scope of the
invention. For example, the theatre structure itself has been shown only
very schematically in Figs. 2 and 3 and may vary according to the particular
preferences of the theatre architect and the environment. The screen 22
preferably has the shape of a segment of a cone as discussed previously, but
alternatively could have the shape of a segment of a cylinder. The screen
structure is preferably a space frame carrying a vinyl screen material which
is painted with a highly reflective paint, all as well-known in the art.
However, other screen configurations could be used, for example,
segmented rigid screens.
