Note: Descriptions are shown in the official language in which they were submitted.
CA 02121054 2002-11-30
.,,
BACKGROUND OF THE INVENTION
The present invention relates to apparatus for stereoscopic
viewing imagery of scenes or objects. For over one hundred years, a wide
range of different types of apparatus have been developed for this
purpose. These apparatus have provided means for viewing one image of a
scene or object with the left eye and an independent, stereoscopically-
related, image for viewing with the right eye of an observer.
Beginning with the parlor stereoscope in the last century, some of these
apparatus have enjoyed a certain level of acceptance in the past, at the
home consumer or public entertainment level. But few, if any, have
retained any significant consumer or public appeal over time.
Various reasons have been put forward to account for the failure of
previous stereoscopic viewing apparatus to achieve wide scale, long term
acceptance. For some apparatus, the need to provide two independent
images has required that viewers wear special glasses, fitted with red-
green or polarizing lenses. Encumbrances such as these have often been
judged to be awkward or irritating to wear. More recently, other types of
apparatus, such as electronically-switched left-right eye liquid crystal
lenses, have been developed for stereoscopic viewing of computer-
generated and TV imagery. These approaches have often been judged to be
too complex and /or costly for all but special stereoscopic viewing
applications.
Early in this century, Gabriel l_ippmann invented integral
photography. This was based on the use of arrays of extremely small
lenses to form three dimensional imagery over relatively wide viewing
angles. Integral photography apparatus eliminated the need for wearing
special glasses. But most consumers have not been satisfied with the
image quality which could be achieved with this type of apparatus. Other
apparatus for stereoscopic viewing of wide angle panoramic scenery on
curved surfaces have used arrays of photographic prints of
anamorphoscopically-distorted imagery as input imagery displays. Arrays
of anamorphoscopic lenses were then used to restore the output imagery
to an undistorted final form for viewing. That is, achievement of
acceptable quality of imagery required use of complex viewing apparatus.
In summary, the failure of mast previous stereoscopic viewing apparatus
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to win wide scale acceptance can be attributed to their complexity, lack
of satisfactory image quality, or lack of convenience to use.
Accordingly, it is an object of this invention to provide a means of
stereoscopic viewing of imagery which is capable of creating the illusion
that three dimensional imagery is being viewed.
Secondly, it is an object of this invention to provide apparatus for
stereoscopic viewing which is not complex , exhibits high image quality,
and is convenient to use.
Thirdly, it is an object of this invention to provide a means for
stereoscopic viewing which does not require the viewer to wear
encumbrances such as special glasses or helmets, etc.
Fourthly, it is an abject of this invention to provide a means for
stereoscopic viewing of relatively large exteruded scenes or objects, by a
number of persons simultaneously.
Fifthly, it is an object of this invention to provide a means for
stereoscopic viewing of TV imagery, which does not require any change in
technical standards for TV broadcasting or video programming
storage.systems.
Sixthly, it is an object of this invention to provide a means to view
imagery of scenes or large objects over a wide range of azimuthal and
elevation viewing angles.
Seventhly, it is an object of this invention to provide a means to
view imagery of objects aver a range of viewing positions around the
imagery.
Additional objects and advantages of the invention will be set forth
in part in the description which follows and in part will be obvious from
the description, or may be learned by practice of the invention. The
objects and advantages of the invention may be realized and obtained by
means of the instrumentalities and combinations particularly pointed out
in the appended claims.
SUNwiARY
To achieve the foregoing objects, and in accordance with the
purposes of the invention as embodied and broadly described herein, a
means for stereoscopic viewing 'is provided which does not require
viewers to wear polarizing glasses or other physical encumbrances. It is
a significant and novel characteristic of this invention that the
stereoscopic effect is achieved through the use of means to form two
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CA 02121054 2002-11-30
independent, but stereoscopically-related, images of a scene or object,
one image which is viewed by the left eye, and one by the right eye of
each of one ar more viewers. The apparatus to achieve this consists of a
number of key elements, each of these being mounted on planar, curved or
multifaceted surfaces which are parallel to each other. On a first surface
is positioned an array of lenses, which can be simple single element
lenses, preferably having the same focal length. For same embodiments,
the lateral shape of these lenses are circular. For others, these shapes
are those of equilateral triangles, squares, ar of regular hexagons, etc.,
which can be packed together to form very closely-packed arrays. For yet
others, the shapes can be those of pentagons,isosceles triangles, or that
of other polygons, which may not be closely-packed together on planar or
curved surfaces. The maximum lateral dimensions of these lenses can
range from fractions of a cm. in some embodiments to many tens of cms.
in others. In particular, their diameters are significantly larger than
those which have been used for integral photography, which are required
to be very small fractions of a cm. These lenses are positioned so as to
form an array,preferably with centres equidistant from each other. For
some embodiments, the lens centres fie on a planar surface, for others
they touch a curved surface, while for still others they lie on each of a
number of facets of a multifaceted surface. For many embodiments, it is
preferable for lenses to be positioned so as to form a very closely-packed
regular array, which for some embodiments can be achieved when edges of
adjacent lenses coincide.
A second element is an array of stereoscopically-related, displaced
and overlapped segments of displayed imagery.of scenes or objects.
Photographic or electronic media can be used for input image display
purposes. In particular for some embodiments , displays of frames of
current conventional TV, or HDTV (High Definition TV) imagery can be
used. The array of input displayed image segments is positioned on a
surface in front of, and parallel to, the surface on which the array of
lenses is located. This surface is separated from that on which the
lenses are positioned by a distance less than the focal length of the
lenses. For many embodiments, the input image segments preferably have
the same lateral shapes and sizes as those of the lenses of those
embodiments. Each output magnified image segment forms a portion of
the complete composite output virtual image to be viewed. The portion of
the image displayed on each segment is displaced laterally from those
portions of the entire image displayed on adjacent image segments. The
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chosen displacement in image between adjacent segments is dependent on
the magnification of the lenses, the distance separation of the lens
centres, the curvature of the surface on which those particular image
segments are located and, in the case of multifaceted surfaces, on the the
relative angular orientation of adjacent facets. Each input image segment
is aligned in front of a lens, which is located on the lens surface behind
it. As a result, on each of the output image surfaces an complete
magnified virtual image is reconstructed which is composed of magnified
segments of the input image segments on each particular input image
surface. These output images are formed on surtaces which lie ahead of
those on which the image segments are displayed.
It is a significant and novel characteristic of all embodiments
of this invention that the left eye and the right eye of each viewer will
each see independent composite virtual images. For various embodiments,
the perspective presented by these two independent images to a viewer
will shift with change in viewing position. For other embodiments the
perspective will not change. Nevertheless, for all embodiments an
illusion is created that the image being viewed is indeed three
dimensional.
A further significant and novel characteristic of this
invention is that stereoscopic TV viewing apparatus can be built which in
the limit requires the transmission and display of a sequence of frames of
only a single channel of standard or high definition two dimensional TV
imagery. Further, other apparatus can be built which requires the
transmission and display of only a few channels of TV imagery.
Embodiments of this invention such as these, which require only a limited
number of TV channels to achieve various levels of stereoscopic viewing
capabilities, do not have the complexities and costs of those embodiments
of this invention which require the capability to provide multiple
channels of TV.
For some embodiments of the inventionadditionalarrays of
stereoscopically-related, segmentsof other
displaced,
and
overlapped
imageryare positioned on other surfaces in f that which the
front o on
lenses or fartheraway from,
are
located.
These
arrays
may
be
closer
to,
the array of images segments from the on whichthe lens
first surface
array located. The positioning of these chosen achieve
is arrays is to the
desiredrelative positioning of the surfaces h the
on whic output
magnified
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a
virtual images are formed. For example, input imagery on the surface
which is closest to that on which the lenses are positioned could be of
foreground objects, and so on for middle ground and background objects or
scenery. As a result, output composite virtual images are formed on each
of a number of display surfaces, and these images will exhibit parallax
with respect to each other. They can be seen by viewers from positions
behind the array of lenses, when looking through the array of these lenses
as though through a window. This capability to form images on surfaces
at a number of different distances from viewers which exhibit parallax
constitutes a third significant and novel characteristic of this invention.
A fourth significant and novel characteristic of this invention is
realized in many embodiments when the lateral shapes of lenses in the
lens array, and the image segments of each of the different input image
segment arrays, are chosen such that very closely-packed arrays can be
formed. As a result, adjacent magnified image segments of the output
composite image can be matched so closely together at their boundaries
that they will form essentially seamless composite virtual images of
scenes or objects on each of one or more particular output image planes.
Further, these output images can be viewed through an array of lenses
which are arranged sufficiently close together to form an essentially
seamless, window-like surface.
A fifth significant and novel characteristic of other embodiments of
this invention is achieved by recording imagery of an object over a wide
range of azimuthal and elevation angles, and then configuring
embodiments of this invention such that images of the object can be
subsequently reconstructed and viewed over a range of azimuthal viewing
angles of up to 360 degrees.and over a wide range of elevation angles.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in, and
constitute a part of the specification, illustrate particular embodiments
of the invention and, together with the general description of the
invention given above and the detailed description of the preferred
embodiments given below, serve to explain the principles of the invention.
FIGURE 1 is a diagrammatic perspective view of one approach
for locating a camera to record imagery of static three-dimensional
scenes or objects at various positions on a plane over a range of
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a
azimuthaf and elevation angles. For some embodiments of this invention
recording takes place in one direction from only one position.
FIGURE 2 is a diagrammatic view of a multiple lens
photographic camera for simultaneously recording imagery of scenes or
objects from various positions, for subsequent stereoscopic viewing by
apparatus according to this invention.
FIGURE 3 is a diagrammatic view of an array of small TV
cameras which can be used for simultaneously recording imagery of
scenes or objects from various positions, for subsequent viewing by TV
stereoscopic viewing apparatus according to this invention.
FIGURE 4 is a diagrammatic perspective view of an
embodiment of this invention for stereoscopic viewing of imagery which
has been recorded by various types of photographic apparatus, such as
those illustrated in FIGURES 1 and 2. For this embodiment, the array of
lenses and the array of image segments are each positioned on planar
vertical surfaces which are parallel to each other.
FIGURE 5 is a central horizontal cross-sectional view of the
embodiment of this invention illustrated in FIGURE 4, for stereoscopically
viewing imagery of three dimensional scenes or objects. This figure
illustrates a means to vary the lateral positions of lenses and input image
segments as may be required in some embodiments of this invention in
which the lenses and input image segments are arranged in the form of
regular, quasi-regular, or irregular arrays. FIGURE f is a central
horizontal cross-sectional view of an embodiment of this invention for
stereoscopically viewing TV imagery of three dimensional scenes or
objects, as recorded by TV camera apparatus such as that illustrated in
FIGURE.3 , or by some other electronic apparatus for subsequent display on
electronic display media. This figure illustrates a means to vary the
lateral positions of lenses and TV image display units, as may be required
in some embodiments of this invention in which the lenses and input
image segments are arranged in the form of regular, quasi-regular, or
irregular arrays.
FIGURE 7 is a central cross sectional view of the embodiment
of the invention illustrated in FIGURE 4, showing light rays from various
subsegments of displayed image segments tn the left and right eyes of a
viewer.
FIGURE 8 A is a diagrammatic perspective view of an
embodiment of this invention which is used for stereoscopic viewing the
imagery of a scene or object which has been recorded in one direction
from only one position, and is displayed such that an illusion is created
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3
that the image being viewed through the plane of lenses is three
dimensional. For this embodiment, the lateral shapes of the lenses and
the input image segments are those of regular hexagons. FIGURE 8 B
illustrates an embodiment which is similar in many respects to that
illustrated in FIGURE.BA, except that the lateral shapes of lenses and
input image segments are those of equilateral triangles. FIGURE 8C
illustrates an embodiment for which the lateral shapes of lenses and
input image segments are squares. This embodiment also has certain
image forming characteristics which are different from those of FIGURES
8 A and 8B. In particular, this figure illustrates an embodiment by means
of which different output images can be sequentially reconstructed on an
output image plane. This is accomplished by the process of synchronously
rotating a number of rods on which rows of associated input image
segments are positioned until the segments for a desired output image are
matched up together to form a complete array of segments on an input
image plane in front of the array of imaging lenses.
FIGURE 9 is an elevation view of one method of dividing up the
plane of an input image display of a scene or object which has been
recorded with a photographic or TV camera.in only direction from one
position, The recorded imagery will be subsequently viewed using
embodiments of this invention such as those illustrated in FIGURES 8 A ,
8 B o r 8 C. FIGURE 9 shows the input display to be divided into
hexagonally-shaped subsegments, as is the case of FIGURE 8 A. These are
arranged to form a closely-packed array.of image segments. The figure
shows five subsegments namely, C'1', ~'2', t~', Cep' and C3 ', along a
central horizontal elevation in the plane of the input image segments.
FIGURE 1 0 is an elevation view of seven hexagonally-shaped
input image print segments or TV frame segments which are based on use
of the particular subsegments illustrated in FIGURE 9. They are here
shown as separated for illustrative purposes although, in practice, they
would be arranged with edges touching to form a closely-packed array of
segments. Each of these seven segments is made up of seven hexagonally-
shaped subsegments and six partial subsegments. There are three
subsegments positioned in a horizontal direction across each image
segment, with the horizontal width of image displacements between
adjacent segments being one subsegment. This arrangement is for a final
image magnification of a factor of three. FIGURE 1 0 shows subsegments
C1, Q and C3 , across the centre of segment 10-3; (3, C3 and G4 , across
the centre of segment 10-4, and C~, G4 and (1; , across the centre of
segment 1 0 - 5.
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s ,:
FIGURE 1 1 is a diagrammatic perspective view of an
embodiment of this invention in which there are two parallel surfaces on
which image segments are positioned. Image segments of foreground
objects are positioned an the surface closest to the lens array, while
those for background scenery and objects. are positioned on a more
distant surface. As a consequence, output virtual images are formed on
each of two separated output image surfaces:
FIGURE 1 2 is a cental horizontal cross-sectional view of an
embodiment of the invention which is configured as a multistage
apparatus for stereoscopically viewing imagery of various types of
objects. Suitable objects may range from single photographic print
recordings of a scene or objects through to a series of frames of recorded
or transmitted TV imagery which are displayed on a conventional TV
display unit.
FIGURE 1 3 is a diagrammatic perspective view of a multistage
embodiment of this invention which is configured for stereoscopic
viewing of displayed TV imagery. This embodiment requires displaying
only a single channel of transmitted TV signals in order to create an
illusion that the TV imagery being viewed is three dimensional.
FIGURE 1 4 is a diagrammatic perspective view of an
embodiment in
which the centres of the lenses and input image segments touch, and are
tangent to, concentric spherical surfaces which are concave towards
viewers. The output composite imagery of background scenery can be
viewed on the more distant spherical output imaging surface over a range
of azimuthal angles of up to 180 degrees, and elevation angles of up to 90
degrees from locations in the vicinity of the centre of the concentric
spherical surfaces. In addition, the output composite imagery of
foreground objects or persons can be viewed on a closer spherical surtace.
FIGURE 1 5 is a diagrammatic perspective view of an
embodiment in which the surface touched by the centres of the lenses is
cylindrical, and is oriented such as to be concave towards the viewers.
Output virtual imagery can be viewed from locations near the axis of the
cylinder.
FIGURE 1 6 illustrates a horizontal equatorial cross-sectional
view of a portion of the embodiments illustrated in FIGURES 1 4 and 1 5,
for which the viewing surface which the centres of the lenses touch, and
are tangent to, is concave towards the viewers.
FIGURE 1 7 is an elevation view of five hexagonally-shaped
photographic print or TV image segments, which could be used as input
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image segments for embodiments such as that illustrated in FIGURE1 5,
and for which the lenses and input image segments are mounted with
their centres touching concentric cylindrical surfaces. Because lenses
and input image segments are located on cylindrical surfaces which are
concave towards viewers, the horizontal displacements of the
subsegments of the image segments of FIGURE 1 7 are necessarily larger
than those displacements of the subsegments of input image segments for
planar surfaces as illustrated in FIGURE 1 0.
FIGURE 1 8 is an elevation view of a strip of output composite
virtual image, as formed by imaging the input image segments illustrated
in FIGURE 17.
FIGURE 1 9 A is a diagrammatic view of one arrangement for
positioning a camera to record imagery of a panoramic scene in each of a
small number of widely-separated azimuthal directions. FIGURE 19 B is a
diagrammatic view of an embodiment of this invention which can be used
for stereoscopic viewing of imagery recorded by an arrangement such as
that illustrated in FIGURE 1 9 A.
FIGURES 2 0 A and 2 0 B are diagrammatic perspective views to
illustrate several methods of pasitioning cameras on convex cylindrical
surfaces in order to record imagery of a person or object in a number of
azimuthal directions around the person or object. FIGURE 20A illustrates
sequential recording of imagery at a number of positions over a range of
azimuthal angles of up to 360 degrees. FIGURE 20B illustrates
simultaneous.recording of imagery in a number of azimuthal directions.
FIGURE 2 1 is a diagrammatic perspective view of an
embodiment of this invention for stereoscopically viewing imagery of the
person recorded using methods such as those illustrated in FIGURES 2 0 A
or 20B. Output reconstructed images of the person are seen to be
contained within a cylindrically-shaped surface which is concentric with
that touched by the centres of the lenses.
FIGURE 22 is a horizontal cross-sectional view of the
embodiment of the invention illustrated in FIGURE 2 1, which illustrates
formation of output imagery on each of a number of planes, which can be
viewed from a number of azimuthal directions.
FIGURE 23A is a diagrammatic view of the multifaceted lens
surface for an embodiment of this invention in which an array of
equilateral lenses is mounted on the surface of an icosahedron. FIGURE
23B illustrates this surtace as it would be seen if it were to be flattened
out onto a plane. FIGURE 23C illustrates another multifaceted lens
surface for which the lateral shapes of the lenses are those of both
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t t
equilateral and isosceles triangles, as this surface would be seen if it
were to be flattened out onto a plane.
FIGURE 2 4 is a diagrammatic view of.the multifaceted surface
of a truncated icosahedron, which is a solid which has twenty hexagonal
and twelve pentagonal facets . As illustrated in FIGURE 2 4, arrays of
lenses can be positioned on some or all of these facets in some
embodiments of this invention. Similarly, arrays of image segments can
be positioned on the faces of one or more concentric truncated
icosahedrans in order to provide a capability to view stereoscopic
imagery from a large number of directions.
FIGURE 2 5 is a diagrammatic view of the well-known geodesic
dome invented by Buckminster Fuller, which is based an use of arrays of
equilateral triangles of various sizes to form a multifaceted surface.
Arrays of lenses and image segments shaped as equilateral triangles can
each be positioned on these facets to form many embodiments of this
invention if it is required to provide a capability to view stereoscopic
imagery over essentially ali directions.
FIGURE 2 f is a diagrammatic view of a recently invented
shape known as a geotangent, or ellipsoidal, dome. This nonspherically-
shaped surface may be chosen as a surface on which to position tenses and
input image segments for various embodiments of this invention.
FIGURE 2 7 A is an elevation view of an embodiment of this
invention in which the lateral shapes of lenses, and those of the
associated input image segments, are regular and nearly-regular hexagons
which touch a spherical surface. FIGURE ~7B is a horizontal cross-
sectional view of the embodiment of FIGURE ~ T A.
DETAILED DESCRIPTION
FIG.1 illustrates a method for photographically-recording
images of three dimensional static scenes or objects, for subsequent
stereoscopic viewing using various embodiments of this invention. A
camera 1 is positioned on vertical plane 2 at location 3-1 and directed
towards the scene or ob;ject~ ts> be recorded. For some embodiments of
this invention , such as those illustrated in FIC~S.4, 5 and 6, imagery is
recorded at each of a number of positions ~-14 3-2, 3-3, etc, which may
be separated from each other by the interocular distance of viewers eyes
of about 6.4 cm. After completion of the recording at positions along one
row over the distance necessary to cover the desired azimuthal angular
viewing range, the camera is returned to the beginning of this row. It is
then displaced downwards and sideways. 'The downward displacement is
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CA 02121054 2002-11-30
preferably between about 5.6 and 6.4 cm, and the horizontal sideways
displacement is offset by a distance of about 3.2 cm. 'Then recording is
recommenced along the next row, with same horizontal separation of
positions of 6.4 cm. This procedure is repeated until an array of displaced
and overlapped images of the scene or ohject has been recorded over the
range of distances required to cover the desired vertical and horizontal
angular viewing range. The downward displacement of 5.6 cm. is chosen
to result in recording at positions which are equidistant from adjacent
recording positions. Except at edges, there will be six equidistant adjacent
recording positions. This pattern of recording; is then matched to a
preferred geometry of the arrays of imaging lenses and input image
segments in various embodiments of this invention for stereoscopic
viewing.
For some embodiments of this invention, such as those illustrated in
FIGS.8A, 8B, 8C, 12, 13, 14, 15, 17, 18 and 2 3 , recording of a scene or
object is required in only one azimuthal direction from only one position,
such as location 3 - 1 of FIC~.1 . For other embodiments, recording may take
place at a number of irregularity-spaced positions on plane 2.
For still other embodiments, recording rnay take place at only a small
number of positions. F1G.2 is a diagrammatic: perspective view of
a multiple lens photographic camera for recording imagery of three
dimensional static or moving objects at a small number of different
positions. Seven objective lenses, 4 -1 to 4 - 7 , of the camera lens array
are illustrated in this figure, although for some embodiments a larger
number of objective lenses may be required in order to cover the angular
field of view required. A side of the camera body, e.g., 5 - 1, is shown
cutaway, to exhibit one of a number of hollow light filter tubes, e.g., 6-1.
Each of these tubular filters, e.g., 6 -1, is mounted between a lens, a g, 4 -
1, and the particular area, e.g.. 7 -1 , of the emulsion surface, onto which
the image formed by this lens is focussed. The inside of these light tubes
. are lined with light absorbing material in order to cutoff the extraneous
light which could otherwise enter the tube from peripheral angular
directions. Each camera subsystem consists of an objective lens, its
associated light filter tube and its associated segment of the emulsion. A
number of these camera subsystems are mounted together in a closely-
packed array configuration as illustrated in FIG.2. This arrangement of
subsystems, together with a shutter for simultaneously exposing the film
in all subsystems, forms a photographic apparatus which is suitable for
simultaneously recording imagery of persons, scenes or objects over a
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' CA 02121054 2002-11-30
a
relatively small angular range as may be required for various
embodiments of this invention.
FIG.3 is an elevation view of a camera arrangement for
recording a scene or object for subsequent stereoscopic TV viewing, using
embodiments of this invention such as that illustrated in FIC~.6 , A number
of TV cameras, 8 - 1 to 8 - 7, with the centres of their objective lenses
separated laterally by a distance which is preferably about that of the
interocular distance, are shown to be clustered together to form a regular
and relatively closely- packed camera array.
FIG.4 is a diagrammatic perspective view of one embodiment
of this invention for stereoscopic viewing of an image of a scene or object
which may have been recorded at a number of regularily-spaced positions
using apparatus such as that described above and illustrated in FIGS.1, 2
or 3. Displays based on the use of photographic prints and transparencies,
or other media, may be employed in various embodiments of this
invention. In particular, various means for displaying imagery such as TV
cathode ray tubes, liquid crystal media, or other electronic displays are
suitable for this and other embodiments of the invention. Photographic
prints are shown in FIG.4 to illustrate this embodiment. They are
mounted on vertical plane 9 of the stereoscopic image viewing apparatus.
Prints 10-1, 10-2, 10-3 and 1 4 - 4, etc, preferably have about the same
lateral height and width as the diameter of imaging lenses 11-l, 11-2,
11-3 and 1 1 - 4, etc, on plane 1 x . The diameters of these lenses can
range from a few tenths of a cm. up to tens of cm. That is, these lenses
have much larger diameters than those used in stereoscopic viewing
systems based on integral photography. The use of such relatively large
diameter lenses constitutes a major difference between all embodiments
of this invention and those systems based on use of the very small lenses
of integral photography. The lenses used in various embodiments of this
invention can be standard types of single or multiple element lenses which
are constructed of glass or plastic. As one example of suitable lenses,
single element Fresnel-type lenses of standard plastic construction have
been used successfully in various embodiments of this invention. The
enlarged virtual image of the scene and objects illustrated in FIG.1 will
then be seen on plane 1 3 by viewers 1 4 from behind plane 1 2 on which
the lenses are positioned.
FIGS is a horizontal cross-sectional view of various
embodiments of this invention, as exemplified by that illustrated in FIG.4.
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CA 02121054 2002-11-30
For these embodiments, photographic prints or transparencies 10-1, 10-
2 and 1 0 - 3, etc, are mounted on plane 9 in either a regular or an
irregular array configuration. As shown in F'1C3.5 these prints or
transparencies preferably have about the same lateral sizes as the
diameters of the imaging lenses 11-1, 11-2, 11-3, etc., which are
positioned on plane 12. When one of these embodiments of the invention
is used to view the output image of a deep three dimensional scene or
object, the lenses may be arranged to form a relatively loosely-packed
array. Furthermore, means 15-1, 1S-2 and 15-3, are provided for each
of these lenses to be moved laterally with respect to each other and hence
to vary the degree of alignment, or relative lateral positioning, of each lens
with respect to the particular print immediately in front of it.
A print and the lens positioned immediately behind, and in
alignment with it, form a subsystem of the embodiment of this invention.
A number of these subsystems are arranged together to form a complete
embodiment of this stereoscopic viewing apparatus. Means 1 6 are
provided to illuminate an array of prints from immediately behind the
array or means 1 7 are provided to illuminate an array of transparencies
from in front of the array. In some circumstances, natural lighting may be
preferable fox illumination purposes.
For many embodiments of this invention, and as illustrated in
FIGS.4 and 5 , prints are positioned on a plane 9 parallel to plane 12 o n
which the lenses are positioned, and at a distance from the plane of the
lenses which is less than the focal length of the lenses. By well-known
laws of optics, the distance separation between lenses and prints can be
chosen to result in a desired magnification of the output image and the
positioning of the plane on which an output virtual image is formed.
Further, the lateral alignment of each particular lens with respect to the
print in front of, and associated with it on the one hand, and the
magnification on the other, determine the lateral position of the output
image of that particular magnified image segment. The particular
displacement of the image segment recorded in each print, relative to the
displacement of the image segments recorded in adjacent prints, can be
laterally adjusted. Under particular conditions to be described below, the
boundaries of adjacent magnified segments of an image can be arranged to
be well-matched to each other so that the output composite reconstructed
image will be essentially seamless. This image will exhibit parallax over a
range of viewing angles which correspond to that of the angular recording.
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CA 02121054 2002-11-30
It can be viewed by one or more persons 14 from positions behind plane
1 2.
FIG.6 is a central horizontal cross-sectional view of an
embodiment of this invention for viewing itraagery recorded using
apparatus such as that illustrated in FIG.3. A regular or an irregular array
of TV monitors,of which three 18-1, 18-2 and 18 - 3, are illustrated, is
used to display recorded frames of TV imagery. This embodiment for
stereoscopically viewing frames of TV imagery is the same in other
essential respects as those illustrated in IpIGS.4 and 5 for viewing
photographic imagery.
Consider now the condition which must be met to achieve
stereoscopic composite imagery which is essentially seamless. This is that
the boundaries of each of the component magnified segments of the
output image must be seen to be closely-matched to the boundaries of
adjacent magnified segments of the image, when viewed through the array
of lenses. This condition is relatively easy to meet in those circumstances
when imagery is recorded of scenes or objects which exhibit little or no
variation in depth. It is also easy to meet when imagery of deep scenery
or objects is recorded over a relatively narrow angular range. In the limit
and as described below for embodiments illustrated in FIGS.BA, 8B, 8C,
9 and 10, it can be readily met if recordings of a scene or object are
made in only one direction from one position.
On the other hand, this condition may be more difficult to
achieve in circumstances when imagery of relatively deep three
dimensional scenery or objects is recorded a~ad subsequently viewed over
a wide range of angles. In such circumstances some parts of the output
image may exhibit areas of badly-matched image segments. This imaging
difficulty arises in part because the various embodiments of the invention
are based on the use of relatively large diameter imaging lenses. These
lenses may subtend appreciable angles when close to objects being
recorded, so that imagery recorded through adjacent lenses may exhibit
noticeably different perspectives and hence be poorly-matched to each
other.
One of the significant and novel characteristics of this invention is
that means are provided to alleviate the problem arising from poorly-
matched image segments described above. As illustrated in FIGS.S and 6 ,
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S
facilities 1S-1, 15-2 and 1 S - 3, etc, are provided in each subsystem of
these particular embodiments by means of which the lateral alignment of
particular array lenses 11-1, 11-2 and 1 1- 3, etc, may be adjusted with
respect to their associated image print segments that is 10-1, 10-2
andl 0 - 3, etc, respectively, as shown in FIGS , or with respect to their
associated TV image display units, that is 18-1, 18-2 andl8-3, etc,
respectively, as shown in FIG.6. Similarly, facilities 19-1, 19-2 and 1 9 -
3, etc, are provided in each subsystem of these particular embodiments
with which to effect lateral adjustments of the subsystem image print
segments as shown in in FIGS , or the TV image displays as shown in
FIG.6. Such adjustments in lateral alignment of lenses with input image
segments can improve the matching of boundaries of particular adjacent
image segments to each other, thereby improving image quality in those
particular portions of the composite image.
Consider now one person looking through the array of lenses on
plane 12 of the embodiments illustrated in FIGS.4, S or b as though
looking through a window, and observing the reconstructed magnified
virtual image. This is illustrated in central horizontal cross-section in
FIG.7 , for the case of a image magnification or a factor of two. The
horizontal cross-section of the image is shown to be divided into three
laterally displaced image segments 10-1, 10-2 and 10 - 3. In turn each
input image segment, which was recorded from a slightly different angle
than were the others, consists of four overlapping subsegments. That is to
say, segment 10 - 1 recorded at one angular direction will be seen to
consist of subsegments Al - 1, A2 - l, A3 - 1 and A4 - 1 when viewed in
cross-section. FIG.7 shows that for the particular viewer location
illustrated, the left eyel 4 - 1 is so positioned relative to the array lenses
11-l, 11-2 and 11-3 that it will see subsegments Al to A6 of the
complete image, when looking, through lenses 1 1 - 1, 1 1- 2 and 1 1 - 3. On
the other hand, the right eye 14-2 will see the subsegments A3 to A8
when looking through these lenses. More generally, when looking through
the entire array of lenses from various distances the left eye will see a
composite image which is stereoscopically-relaited to, displaced from, and
independent of the image seen fly the right eye.
This is a significant feature of this and all embodiments of the
invention. That is, this invention provides a novel and straightforward
method to provide two independent images, one for each eye of one or
more viewers. This is based on particular arrangements of image
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segments and the positioning of simple lenses behind them.for the various
embodiments. By such arrangements these embodiments eliminate need
for polarizing glasses, the complexities and expenses of special distorting
lens combinations, and are not subject to the inadequacies of integral
photography image quality. These are the prices which have had to be
paid far using one or another of the various other approaches to meeting
the need to provide two independent images in stereoscopic image
viewing systems.
FIG.B A illustrates an embodiment of' this invention which is
based on a novel approach to avoid the problems arising from recording
deep scenes or objects aver wide angular ranges. This approach is based
on the strategy of recording such scenes or objects at one position and in
one direction only, for example recording with the camera located only at
position 3 - 1 in FIG.1 and recording imagery in only one direction. This
approach can be successful because of a little-known characteristic of
stereoscopic vision. This is that by using an appropriate type of
apparatus for stereoscopic viewing, an illusion can be created that a three
dimensional image is being viewed, even if the input imagery which is
recorded is that of an object as seen in one direction from one position.
The embodiment illustrated in FIG.BA achieves this by displaying an
array of images of the two dimensional scene or abject such that the
imagery to be seen by the left eye of an observer is stereoscopically-
related to,offset from, and independent of the image of the scene or object
to be seen by the right eye of the observer.
The embodiment shown in a diagrammatic perspective view in
FIG.BA consists of elements having essentially the same functions as those
of the embodiment illustrated in FIG.4 for viewing imagery of scenes or
objects which had been recorded aver a range of angles. The first element
is an array of imaging lenses 20-l, 20-2 and 2 0 - 3, etc, mounted on a
vertical plane 1 2. Far this embodiment, the lateral shape of each these
lenses is chosen to be that of a regular hexagon, and they are arranged
together in the form of a very closely-packed ~uray.
The second element is mounted an a vertical input image display
plane 9. It consists of an array of input image segments 21-1, 21-2 and
21- 3 , etc, which could be photographic prints, photographic
transparencies, or TV image display segments of the complete input image
display. These segments are stereoscopically-related, displaced and
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overlapped versions of each other. The array of recorded image segments
is positioned in front of, and aligned with, particular lenses 2 0-1, 20-2,
2 0 - 3, respectively. The lateral shape of each of the image segments in
FIG.BA is that of a regular hexagon, having the same size as that of a lens.
Taken together, a lens 2 0 - 1, e.g, and the particular input object segment
2 1 - 1 in front of and in alignment with it, form a subsystem of the
complete apparatus. The plane 12 is so positioned longitudinally that the
distance between it and plane. 9 in front of it is less than the focal length
of the lenses. As a consequence, a magnified virtual composite image of
the input object display is formed on plane 1 3 which lies ahead of plane
9.
The principal differences between the embodiments
illustrated in FIG.BA and FIG. 4 arise from the differences in strategy
adopted for choosing the input image segments and their relative
displacements. By following this strategy major objects of this invention
can be realized. First, the displacements of input image segments are
chosen so that the output magnified virtual imagery segments are closely-
matched together. Secondly, the shapes of lenses and input image
segments are chosen so that they can be arranged to form closely-packed
arrays. As a result the output composite image will appear to be
essentially seamless and can be viewed by a number of viewers at the
same time. Embodiments exemplified by that illustrated in FIG.8 A
achieve this by choosing regular hexagons as the lateral shape of lenses
20-1, 20-2 and 2 0 - 3 , etc, and input image segments 21-1, 21-2 a n d
21-3, etc, and arranging these lenses and input image segments into
closely-packed arrays. In a similar manner, embodiments exemplified by
that illustrated in FIG.8 B achieve this by choosing equilateral triangles as
the lateral shape of the lenses, 22-1, 22-2 and 2 2 ~ 3, etc. and input
image segments 23-1, 23-2 and 23-3, etc. Further, embodiments
exemplified by that illustrated in FIG.BC achieve this by choosing squares
as the lateral shape of the lenses 24-1, 24-2 a n d 2 4 - 3 , etc, and the
input image segments 25-l, 25-2 and 25-3, etc and arranging these
together other as shawn,
FIG.BC also illustrates a means of mounting three different sets of
input image segments in front of the one array of lenses 2 4 - 1, etc, in such
a manner that three different reconstructed output images can be
sequentially selected and and presented for viewing. As illustrated in
FIG.BC, each horizontal row of image segments 2 5 - 1, etc, associated with
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CA 02121054 2002-11-30
one particular output image is mounted on ore of the three faces of a
horizontal mounting rod 26~1, etc, which has a cross-sectional shape of an
equilateral triangle. These mounting rods are positioned one above the
other on a vertical place. Means are provided to rotate each of these rods
about an axis 2 7 - 1, e.g, which runs through the centroid of its cross-
section. In operation, the rods are rotated until the input image segments
associated with the first output image on each rod are aligned with each
other and lie on the vertical plane 9. The first output image is then
reconstructed on plane 13. Similarly, when it is required to reconstruct
another output image on plane 1 3 , all of the rods are rotated together
through an angle of 120 degrees so that input image segments associated
with the second complete output image will lie on the plane 9. Rotation of
the rods through a further 120 degrees results in the image segments
associated with a third output image becoming aligned and lying together
on the plane 9. In other similar embodiments,which are not illustrated
here, the rods may have thin rectangular cross-sections, thus providing a
capability for displaying either, or indeed neither, of only two sets of input
image segments. In still others, also not illustrated here, the rods may
have square or polygon-shaped cross-sections
FIG.9 is an elevation view of a method of dividing up the the plane
of an image display of a scene or object, which has been photographically
recorded at only one pasition, e.g., 3 - 1, and in one direction, as
illustrated
in FIG. 1. This recorded image will subsequently be viewed using an
embodiment of this invention such as that illustrated in FIG. 8A. The
input image display is divided into hexagonally-shaped subsegments,
arranged in the form of a closely-packed array. FIG.9 shows five
subsegments Cl ', C2 '~3 ', C4 ' and CS ' along a central horizontal elevation
section of the input image display.
FIG.10 is an elevation view of an arrangement of seven hexagonally-
shaped input photographic image prints or TV image frame segments 2 1 -
1, 21-2, 21-3, 21~4, 21-5, 21-6 and 2 1 - 7 which has been formed by
positioning the subsegments of FIG.9 together as a closely-packed array.
In FIG.1 0 these segments are shown to be separated from each other, for
illustrative purposes only. In practice they would be arranged to form a
closely-packed array with no distance separating them. Each of these
seven segments is madt: up of seven hexagc>nally-shaped subsegments and
six partial subsegments. There are three subsegments in the horizontal
elevation section of each image segment, with a horizontal displacement
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between those adjacent segments which is chosen to be the width of one of
the three subsegments. This is the required displacement for a final image
magnification of a factor of three. For example, FIG.10 shows a central
horizontal elevation section, consisting of subsegments Cl , C2 and C3 of
segment 21- 3 ; CL , C3 and C4 of segment 21- 4 ; and C3, (~ and CS , of
segment 2 1 - 5. FIG.1 d also shows that the subsegments C1 to C5 in the
upper segments 2 1 - 1 and 2 1 - 2 are displaced vertically downwards by
one third of the height of the segment. Similarly, the same subsegments in
the lower segments 21 -6 and21 - 7 are displaced vertically upwards by
amounts appropriate for a magnification of a factor of three.
More generally, for input image segments mounted on a planar
surface, the correct displacement of images between adjacent print
segments will be equal to the separation of the centre lines of the lenses,
divided by the magnification of the output image.
For images recorded at only one location and in one angular
direction, the above choices crf relative displacements of image
subsegments in each input image segment ensure that the boundaries
between the magnified segments of the output image on plane 1 3 will be
closely-matched with each other. This has several favourable
consequences for output image quality. First, the resulting composite
image will be essentially seamless. That is, there will be no ill-matched
boundaries between segments to detract from overall image quality, such
as may arise when viewing imagery of deep three dimensional input
objects which may have been recorded over a wide angular range.
Secondly, because there is no longer any uncertainty about the required
relative displacements of adjacent input image print segments, or of TV
imagery displayed on each of the monitor units to achieve the most
satisfactory output image far viewing, the arrays of final imaging lenses
and input image segments do not necessarily have to be adjusted laterally,
as may be the case for embodiments such as those illustrated in FIGS. 5
and 6. Instead, the arrays can be arranged to form very closely-packed
arrays. For various embodiments of this invention, the design of such
closely-packed arrays can be based on choice of regular hexagons as
lateral shapes for the lenses and input image segments, as illustrated in
FIGS. &A, 13, 24 and 27. Alternately, these shapes can be those of
equilateral triangles, as illustrated in FIG. 8 B, or squares, as illustrated
in
FIGS.8C and 15 , Further, by using these shapes, the arrays of lenses can
be constructed in the fc>rm of essentially continuous, window-like surfaces,
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CA 02121054 2002-11-30
through which composite and essentially seamless stereoscopic imagery
can be viewed on plane 13.
FIG.1 1 is a diagrammatic perspective view of an embodiment of this
apparatus for which there are two surfaces an which input image
segments are positioned and for which the input image segments have
been recorded as described and illustrated in FIG.4. Input image
segments 28-2, 28-3, etc., of foreground objects are positianed on
vertical plane 2 9, which is positianed closer to the plane 12, on which the
lenses are located than is plane 9 , an which the input image segments of
the background scenery and objects are located. As a result, a magnified
virtual image of the foreground objects will kre seen by viewers 1 4 to be
reconstructed on plane 3 0 which lies closer to the plane 12 than does
plane 1 3, on which the magnified virtual imagery of the background
scenery and objects are formed. Far some embodiments, the input image
segments for foreground imagery.on one plane could be positioned on the
planar faces of rods as described far the embodiment illustrated in FIG.BC.
By rotating these rods, output foreground imagery formed on one output
image plane can be changed without affecting the output imagery formed
on other planes.
Various embodiments may have a large number of input image
surfaces. For many of these embodiments it may be desirable that correct
size and positional relationships exist between output magnified images on
different surfaces. This can be accomplished by appropriate choice of
relative sizes and longitudinal positional displacements, and hence output
image magnification, for the input image segments on each surface.
FIG.12 is a central horizontal cross-sectional view of a
different type of embodiment of this invention in which displays of
scenes or objects are directly presented as inputs for stereoscopic
viewing. Suitable inputs could range from a single image display of a
scene or object as viewed from one location, through to a display of a
series of frames of TV imagery, as presented on the screen of a single TV
display unit. This particular embodiment differs from those illustrated in
FIGS.BA, 8B and 8C in that only one input object display is required.
That is to say, instead of preparing an array of previously recorded,
displaced and overlapping input image segments, this embodiment
includes one or more additional optical stages for directly forming an
array of displaced and overlapping image segments of the desired object
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CA 02121054 2002-11-30
within the apparatus itself. In other words, it can be described as
combining many of the Characteristics of image recording systems such
as those illustrated in FIGS,1, 2 and 3 with embodiments of this
invention such as those illustrated in FIGS. 8A,88 and 8C.
In FIG. 12 a photographic print is used as the input object used in
this embodiment. The print is mounted upside down on plane 3 1. The
method illustrated in FIGS.9 and 1 0 for dividing up the plane of an input
image display to form a closely-packed hexagonally-shaped array is also
used for this embodiment. Central cross-sections of the particular
subsegments L, K, J, I, and I~ are shown on plane 3 1 of FIG.1 2. Light from
all subsegments of the input object display on plane 3 1 falls on a closely-
packed array of lenses on plane 32. This array constitutes the primary
imaging lens array and in this embodiment it is chosen to have an output
image magnification of a factor three. 'Three lenses 33-1, 33-2 and 3 3 - 3
of those in the primary imaging lens array are illustrated in FIG.12. One
lens, or a system comprising more than one lens, is used to form each of
the input image segments required in the array. These lenses, or lens
systems, each have the same focal length and are mounted on the vertical
plane 32 at a distance greater than the focal length.from the plane of the
input object display 3 1. As a result, an array of upright real images is
focussed an a vertical plane 34 located behind the plane 3 2 at a distance
greater than the focal length of these lenses. A sheet of imaging frosted
glass or plastic is positioned on plane 34 onto which this array of images.is
focussed. Plane 34 then becomes the input image display plane. This
embodiment is sa configured that the relative displacements of adjacent
segments of the focussed images on plane 3 4 are the same as those of the
adjacent displayed prints of the input object display on plane 9 of the
embodiments illustrated in F1GS.8A, 8B and 8C. As a consequence, the
embodiment illustrated in FIG.12 achieves tire object of providing a means
for stereoscopic viewing magnified output imagery, as do the
embodiments illustrated in FIGS.8A, 8B and 8C. That is, it provides a
means for the reconstruction of a magnified output virtual composite
image on plane 3 5 which will have a seamless appearance when the
boundaries of adjacent magnified segments of image contributions are
closely-matched with each other. For this embodiment these particular
image segments, and only these segments, of the complete images of the
input object display are imaged on plane 3 4 . Means are provided for
extraneous light to be filtered out of each particular image segment on
plane 34, particularly light from adjacent image segments. As illustrated
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CA 02121054 2002-11-30
in FIG.1 2, this filtering is such that only light incident on the lenses on
plane 3 2 over the correct range of angles will contribute to the formation
of images on plane 34. The required filtering is accomplished through the
use of hollow tubular light filters 36-1, 36-2 and 3 6 - 3, etc, with their
inside surfaces lined with light-absorbing material. Each of.these tubular
filters is positioned with a lens, e.g., 3 3 -1 ,.mounted at one end of the
filter
and the particular image segment display 3 7 - 1 associated with it
mounted at the other, as shown in FIG.12. At the lens end, these tubes
preferably have the same cross-sectional width and shape as the lateral
shape of the lenses themselves. Far example, they may have a hexagonal
shape of the same width. Also at the image display area end, a tubular
filter preferably has the same width and shape as that of a final imaging
lens, e.g., 20-1 on plane 1 2. For example, the filter may have a hexagonal
shape of the same width as this lens. As.a result of this filtering, and as
illustrated in FIG.12 for image segments in the central horizontal cross-
section, the image segment display e.g., 3 7 - 1 exhibits only the displaced
images of subsegments H', I' and J', the images of subsegments K, L and all
others being filtered out through absorption by light filter 36-1 ; the
image segment display 3 7 - 2 exhibits only the displaced images of
subsegments I', J' and K', the images of subsegments H, L, and all others
being filtered out through absorption by light filter 36-2 ; and the image
segment display 37-3 exhibits only the displaced images of subsegments
J', K', and L'.,the images of subsegments H, I, and all others being being
filtered out through absorption by light filter 3 6 - 3.
The lateral distance separation of optical centre lines chosen
for the primary image array lenses on plane 32 is that which is necessary
to achieve the correct relative displacement of particular image segments
focussed onto plane 3 4 , for example, the correct relative displacement of
one image segment, eg., 3 7 - l; relative to that of an adjacent image
segment, eg, 3 7 - 2. As a result, a magnified virtual composite image with
closely-matching boundaries between the magnified image segments will
be viewed as a complete and seamless image on plane 3 5 . In other words,
the same object has been achieved as that fc~r the embodiments illustrated
in FIGS.$A, 8B and 8C, but without the need to create the input image
segments in separate image recording and image segment production
apparatus.
Another embodiment of this invention as a multistage
apparatus can be used for viewing of stereoscopic TV imagery. In this
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CA 02121054 2002-11-30
embodiment a sequence of individual frames of displayed TV imagery,
which have been recorded from one TV camera position according to
conventional practice before being transmitted or stored, becomes the
input object display. 'this embodiment is illustrated in a diagrammatic
perspective view in FIG.1 3. A TV set is shown positioned on its back with
its image display surface 3 8 an a horizontal plane 3 9 so that the display
surface is facing upwards. As illustrated in F1G.1 3, the set is oriented so
that the first line of the scan 40 exhibits the capital letters A to G of
which
only the letter G is visible in this figure. The input to the set is single
channel of standard TV signal transmission which has been .received using
a broadcast receiver or a video recording apparatus. Frames of TV
imagery are displayed on the set in a conventional manner. After
reflection by inclined mirror 41, light from a displayed frame falls on the
closely-packed array of primary imaging lenses 33-1, 33-2, etc, of which
only 33-6 is fully seen in this figure. The other elements in this
embodiment exhibit the same characteristics as those of the embodiment
illustrated in FIG.12. Hollow tubular light -absorbing filters 36-6 cg,
extend from each of the lenses 3 3 - 6, cg, to the area of the particular
image segment 3 7 - 6 , cg, on plane 34 with which it is associated. FIG.13
shows this filter cut away to exhibit the lens, 3 3 - 6. Each of the final
imaging lenses, 2 0 - 6, e.g, an plane 12 are used to form a segment of the
magnified composite virtual image on plane 3~. This image may be seen
by one or more viewers 14 behind the piane of lenses 12.
The imaging characteristics of the second stage of this multistage
embodiment for stereoscopic TV viewing are essentially the same as those
of the single stage embodiments for stereoscopic viewing of static
photographic imagery which are illustrated in FIG5.8A, 8B and 8C. As a
consequence, the advantages o1~ stereoscopic viewing of imagery recorded
in one direction at only one position and which have been described for
other embodiments of this invention also apply to this multistage
embodiment for viewing TV imagery. In particular, this embodiment
provides a relatively straightforward means to switch from a conventional
mode of TV viewing to that ilU.istrated in F1G.1 3 for stereoscopic TV
viewing. This switchover can be accomplished simply by appropriately
reorienting the TV set relative to the multistage stereoscopic viewing
apparatus of this embodiment to foam an arrangement such as that
illustrated in FIG.1 3.
The multistage embodiment of FIG.1 3 can provide economically
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CA 02121054 2002-11-30
important advantages. This is because it is significantly less expensive
than embodiments such as those illustrated in FIGS.BA, 8B and 8C which
require an array of 'rV image display units, such as illustrated in FIG.6.
On the other hand, the upper limit on achievable image quality of any
multistage apparatus, exemplified by those illustrated in FIGS.12 and 13 ,
will necessarily be somewhat less than that achievable with a single stage
apparatus.which has the much greater transmission and display resolution
capability afforded by use of many TV channels.
Variations of the embodiment illustrated in FIG.l 3 could be
constructed with an output composite image size which is significantly
larger than that which can be displayed on standard size TV display tubes.
Upper limits on the size of the output virtual image depend on various
factors. These include the number of picture elements(pixels) per line and
lines per frame of currently -available TV technology. In the future,
introduction of HDTV (high definition TV )technology, for example, that
based on proposed MUSE standards( 1125 lines/frame), or HD-MAC
standards( 1250 lines/frame) could, in principle, lead to adoption of larger
image sizes with high image quality. A second factor is output image
brightness which could fall below acceptable levels if the magnification is
too great. Embodiments of this invention which use a fibre optic faceplate
on a 'TV display tube can overcome viewing problems resulting from low
image brightness. Finally, a number of embodiments, exemplified by that
illustrated in FIG.1 3, can be positioned together to form other
embodiments capable of forming stereoscopic imagery on each face of a
multifaceted surface.of ehe type similar to those illustrated in
FIGS.19B,22, 24, 25, 2C~, an d 27 and this multifaceted TV image surface
can then be used to view imagery over a wide angular range. For such
embodiments, imagery formed on each face could require transmission
and reception of one channel of TV broadcasting or pragramming.
In summary, various embodiments of this invention can be
constructed for stereoscopic viewing of TV imagery as exemplified by the
embodiment illustrated in FIG 1 3, for which only one TV image display
unit is required, or based on embodiments as exemplified by those
illustrated in FIGS 6, 8A, 8B, 8C, 22, 24, 2~, etc, for which a number of
TV display units are required, each displaying one channel of TV
broadcasting or programming signals. In the future, introduction of HDTV
broadcasting will provide increased opportunities for stereoscopic viewing
of high quality TV imagery on wide area display units.
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CA 02121054 2002-11-30
FIG.14 is a diagrammatic perspective view of an embodiment of
this invention which is suitable for viewing stereoscopic imagery over
azimuthal angles of up to 180 degrees and elevation angles from the
horizon to the zenith. Viewing of imagery over such a wide angular
viewing range is possible from near central locations such as 14 - 1.
Viewing imagery over narrower viewing ranges is possible from other
viewer positions such as 14 - 2 and 14 - 3. The spherical surface 4 2 which
is touched by the centres of the imaging lenses, and to which the surface
of the lenses are tangent, presents a concave surface towards viewers. For
this embodiment, the lateral shape of each lens, e.g., 1 1 - 1, and input
image segment, e.g., 10 - 1, are circular. For the embodiment illustrated in
FIG.14, input image segments for background imagery are positioned on
surface 4 3 so that magnified virtual background imagery will be formed
on surface 4 4. In addition, input image segments for foreground imagery
are positioned on surface 45, resulting in magnified foreground imagery
being formed on surface 4 6.
Lenses and input image segments for embodiments which provide
wide angular viewing ranges may have lateral shapes chosen to produce
essentially seamless composite imagery. As described below, these lateral
shapes may be hexagonal, as illustrated in FIGS 24 a n d 2 7, or triangular,
as illustrated in FIGS .23A, 23 B, 23C a n d 2 ~.
FIG.15 is a diagrammatic perspective view of an embodiment in
which one cylindrical surface 47 is touched by the centres of the lenses
and another surface 48 is touched by the the input image segments. The
surfaces of the lenses and image segments are tangent to these surfaces,
respectively. The cylindrical surface 4 7 is concentric with surface 4 8 and
is oriented to be concave towards viewers 14 with its axis being vertical.
For this embodiment, the lateral shapes of the. lenses 2 4 - 1, etc, and input
image segments 2 5 -1 , etc, are square, although other shapes such as
hexagonal may be used. The complete output magnified image is formed
on cylindrical surface 4 9 . From central viewing locations, eg, 14 -1 ,
viewing imagery over a range of azirnuthal angles up to 180 degrees is
possible. From other locations, eg, 14-2 and 1 4 - 3 , viewing imagery over
somewhat narrower range of arimuthal angles is possible.
FIG.16 is a central equatorial cross-sectional view of the
embodiment of this invention, which is illustrated in FIG.14. The centers
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CA 02121054 2002-11-30
a
of lenses 1 1 - 1, 11-2 and 1 1 - 3 touch a spherical surface 42 and the
surfaces of these lenses are tangent to this surface. Subsegments A,B,C
and D are exhibited in cross-section on input image segment 10 -1,
subsegments C, D, E and F on input image segment 10-2, and subsegments
E, F, G, and H on input image segment 1 0 - 3. The centres of these input
image segments touch spherical surface 4 3. 'fhe magnified output images
of these subsegments, namely ,~', B', C', D', E', F', G' and H' are
reconstructed
on surface 4 4 to form a complete and seamless output image which can be
seen by a viewer 14 from locations near the centre of the spherical
surfaces.
FIG.1 7 is an elevation view of five hexagonally-shaped input image
segments 21-1, 21-2, 21-3, 21-4 and 21-5 which may be displays of
photographic prints, photographic transparencies, or TV imagery. The
segments illustrated in FIG.1 7 are shown to be separated from one
another for illustrative purposes only. In practice they would be arranged
to form a closely-packed array with no distance separating them. Four
subsegments can be seen in the central section of each these segments.
These may be positioned in an embodiment such as that illustrated in FIG
15, in which the arrays of lenses and input image segments are mounted
with their centres touching concentric cylindrical surfaces. The cylindrical
surfaces on which the lenses and input image segments are mounted in
this embodiment have concave curvatures towards viewers. Because of
this, the required horizontal displacements of the image subsegments
shown in FIG.17 are larger than those of the image segments illustrated in
FIG. 10, for otherwise similar embodiments with planar surfaces. But the
vertical displacements are the same for both types of embodiments. for the
same image magnification.
FIG.18 illustrates an elevation view of a strip of the output
composite image,showing the magnified overlying images of segments of
FIG.1 7, namely.2 1-1', 21-2', 21-3', 21-4' and 21-5', The output
image to be seen to be an essentially seamless composite image of the
magnified subsegments, namely C1', C~', C3', C4', C5', C6', C7' and C8'.
Various embodiments, exemplified by those illustrated in FIGS.1 4
and 1S. are suitable far viewing imagery of scenery over a wide azimuthal
angular range. These embodiments provide output imagery which is
essentially continuous across a wide field of view. Other embodiments,
exemplified by that illustrated in F1G.19B, are also suitable for viewing
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J
imagery wide azimuthal angular range. A distinguishing feature of an
embodiment such as that illustrated in F1G.19B is that the composite
output imagery is made up of component imagery recorded at only a small
number of azimuthal directions within a wide field of view. FIG.1 9 A
illustrates a method of recording imagery in each of a small number of
azimuthal directions, which then may be processed and and positioned in
an embodiment such as that illustrated in FIC:~. 19B. Imagery of the scene
is recorded by a camera 1 which is positioned sequentially on each of a
small number of vertical planes 2-1, 2-2, 2-3, 2-4 and 2-S which are
normal to the azimuthal angle recording directions. The recording and
subsequent input image segment preparation procedures required to
obtain input image segments for each of these azimuthal recording
directions are then essentially the same as those followed for recording
and subsequent processing at only one azimuthal angle, such as those
required for embodiments illustrated in FIGS.8A, $B and 8C. That is to
say, each recorded image is processed to obtain an array of
stereoscopically-related, displaced and overlapping image segments as
illustrated in FIGS.9 and 10. Subsequently, and as illustrated in FIG. 19B,
one array of square-shaped imaging lenses 24-1, 24-2, 24-3, etc, is
mounted on one planar facet, e.g., 12 - 3 , of the multifaceted surface of
lenses 1 2. An array of input image segments 2S-1, 2S-2, 2S-3, etc, is
mounted on one planar facet 9 - 3 of the multifaceted surface of input
image segment 9. These input image segments are positioned in front of,
and in alignment with, particular lenses 24-l, 24-2, 24-3, etc,
respectively. Output magnified imagery reconstructed from input image
segments of this planar facet is then formed on output image surface, eg,
13 - 3 . Similarly, arrays of lenses are mounted on other planar facets 1 2 -
1, 12-2, 12-4 and l 2 - S and arrays of input image segments are
mounted on other planar facets 9-1, 9-2, 9-4, and 9-S. This results in
reconstruction of output magnified images on planes 13-1, 13-2,
13-3, 13-4 and 13-S. As a result, a complete image will be
reconstructed which is itself a composite of the five component output
composite images. For some applications, embodiments exemplified by
that illustrated in FIG.19B may be preferred over those illustrated in
FIGS.14 and 1 S. For such applications recordings and image
reconstruction made at only a few azirnuthal directions may suffice to
obtain a composite output image which exhibits acceptable quality. For
other applications, recordings and image reconstruction made at a larger
number of azimuthal (and in some casr;s elevation ) angles may be
necessary in order to obtain a composite outlrut image which exhibits
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i
acceptable quality. For these applications embodiments such as those
illustrated in FIGS. 14 and 1 5 may be preferable.
FIGS.20A and 20B are diagrammatic perspective views of
camera positions on a convex cylindrical surface 5 0 for recording imagery
of a person 5 1 or object, over a wide range of azimuthal angles centred on
the person or abject. 'The person or object is positioned within a
cylindrical surface 52 which is concentric with the cylindrical camera
recording surface. FIG.20A illustrates camera locations of a camera 1 for
sequentially recording views of the person or object from a number of
positions over a range of azimuthal angles of up to 360 degrees. FIG 2 0 B
illustrates a method for simultaneously recording imagery of the person
1 at a number of aaimuthal angular positions 53-1, 53-2, etc, on the
cylindrical camera recording surface 50.
FIG.21 is a diagrammatic perspective view of an embodiment
of this invention for stereoscopically viewing imagery 54 of the person 5 1
which was recorded over a range of azimuthal angles by methods such as
those illustrated in FIGS.2 0 A or 2 0 B. Inspection of FIG.21 shows that the
output virtual image 54 is contained within a cylindrically-shaped surface
55 which is concentric with the cylindrical surface 56 on which the lenses
2 0 - 1, ete, are positioned. It is also concentric with the cylindrical
surface
5 7 on which the input image segments 21- I , etc, are positioned. The
output image 5 4 can be seen by viewers 14 from various perspectives
over an omnidirectional range of viewing positions, which is the same as
that over which recording took place.
FIG 22 illustrates a portion of the horizontal cross-sectional
view of the embodiment of the invention illustrated in FIG.21. The
centres of lenses 20-1, 20-2 and 20-3 touch the cylindrical convex
surface 56. Similarly, the centres of input image segments 21-1, 21-2
and 2 1 - 3 touch the cylindrical surface 5 7. FIG.22 shows that output
images are formed on planes parallel to thaw on which the input images
are positioned. That is to say. when looking through a lens 1 1-1, eg, at
input image segment 2 1 - r, on which subsegrnents A-1 through to L-1 are
located, a viewer 1 4 - 1 will see magnified images of these subsegments on
plane 5 8 - 1. Similarly, when looking through lens 20-3 at input image
segment 21-3 on which subsegments C-3 through to N-3 are located, a
viewer 1 4 - 3 will see magnified images of these subsegments on plane
5 $ - 3. That is to say, as the point of view of a viewer changes from one
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position to another around the cylindrical surface on which the lenses are
positioned, the perspective of an image will change accordingly. In most
essential respects, this is the same change in perspective as that which
would be seen by a viewer looking through the cylindrical surface S 6 of
lenses, if subsegments A through to N were to be positioned on the three
dimensional cylindrical surface 5 5. FIG 2 2 also shows light shields 5 9 -
1,59-2, 59-3, etc, which are positioned at the edges of the input image
segments 21-1, 21-2 and 21-3, etc. These shields cut off viewing of
distorted output imagery which would otherwise be seen when viewing
imagery through the surface of lenses at oblique angles.
FIGS.2 3 A and 23B illustrate surfaces of various embodiments of this
invention, for which the lateral shapes of lenses are equilateral triangles.
Arrays of these lenses are positioned on planar facets of the surface of an
icosahedron. FIGS.23A and 2 3 B illustrate an embodiment in which nine
lens 22-1, 22-2, 22-3, etc, , each with the lateral shape of an equilateral
triangle, are positioned on each of the twenty facets of this surface. FIG.
2 3 A is a diagrammatic perspective view of this surface, and FIG.23B is a
view of the same surface as it would appear of it were to be flattened out
onto a plane. The input image segments for this embodiment are
positioned on the surface. of another icosahedron which is concentric with
that on which the lenses are positioned. Various embodiments,
exemplified by that illustrated in FIG.23A,can be used by a viewer 1 4
who, when looking looking through the viewing surface formed by the
array of lenses, will see imagery over a wide range of perspectives from
positians around, above and below this surface, For these embodiments
the array of lenses is mounted on facets on the outside surface of an
icosahedran so that a convex surface is presented to viewers. Because the
twenty facets of this surface completely cover° a sphere, these
embodiments provide a capability to view imagery aver a greater range of
elevation angles than may be possible with embodiments exemplified by
that illustrated in FIG.21. Other embodiments can be used to view
imagery of panoramic scenes cor objects over a wide range of azimuthal
and elevation angles. For these embodiments the array of lenses are
mounted on the inside surface of an icasehedron so that a concave surface
is presented to viewers. Because the twenty facets of this surface cover a
sphere, these embodiments provide a capability to view imagery over a
range of elevation angles which is comparable to that provided by the
embodiments exemplified by that illustrated irt FIG.l4.and is greater than
that which can be provided by the embodiments exemplified by those
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illustrated in FIGS.15 and 19 B.
Embodiments which use the multifaceted surface of an icosahedron
on which to position arrays of lenses, as exemplified by those illustrated in
FIGS.2 3 A and 238, have a capability to view imagery over a wide range
of angles. However this capability is nevertheless limited to only twenty
relatively widely-spaced angular directions. fin the other hand,
embodiments exemplified by that illustrated in FIG.23C, while similar in
many respects to that of FIGS. 2 3 A and 2 3 B, have a capability to extend
the number of angular viewing directions essentially without limit. This
embodiment is illustrated as it would appear if it were to be flattened out
onto a planar surface. Lenses 22-1, 22-2, 22-3, etc, have the lateral
shapes of either equilateral or isosceles triangles. These are shown
arranged in rows in which lenses 22-1,22-3, etc, in the central row,all
have the lateral shape of equilateral triangles and lenses 2 2 - 2 , etc, in
all
other rows have lateral shapes alternating between those of equilateral
and isosceles triangles. Embodiments with multifaceted surfaces which
are formed with arrangements of triangles such as that illustrated in
FIG.23C can be designed to have as many facets, and hence can provide as
many viewing directions as may be desired.
FIG.24 is a diagrammatic perspective view of a surface composed of
twenty hexagons and twelve pentagons, arranged to form the surface of a
truncated icosahedron. This surface can be used in various embodiments
of this invention as a multifaceted surface on which to mount lenses and
image segments which have hexagonal and pentagonal shapes. FIG.2 4
illustrates how seven complete hexagonal lenses 20-1,20-2,20-3, etc,
and six partial lenses can be positioned on each of the twenty hexagonally-
shaped facets of this surface for various embodiments of this invention.
FIG.25is a diagrammatic view of the geodesic dome invented by
Buckminster Fuller, which is based on use of a large array of equilateral
triangles of several sizes to form the surface of the dome. This can be
used as a surface on which to position arrays of lenses and input image
segments for various embodiments of the invention in which multifaceted
surfaces are required to be tangent to, and touch, a spherical surface.
Various embodiments using this type of surface may be used to provide a
capability to view imagery in each of an essentially unlimited number of
directions. Therefore these embodiments have a viewing capability
comparable to various other types of embodiments such as those
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exemplified by the embodiment illustrated in FIG .23 C.
F 1 G . 2 6 is a diagrammatic view of a new type of dome, known as a
geotangent dome, which has only recently been invented. This surface is
formed of a number of hexagons and pentagons. It can be used as a
surface on which to position arrays of lenses and input image segments for
various embodiments of this invention in which it is required that the
surfaces be tangent to, or touch, an ellipsoidal surface.
fIG. 27 A is an elevation view of an embodiment of this invention, for
which the lateral shapes of lenses, and those of the associated input Image
segments, are those of regular hexagons. In other respects, this
embodiment is similar to that illustrated in FIG.1 4. The lenses are
positioned so that the centre of each of the lenses touches a spherical
surface 42. Those image segments which form the imagery of foreground
objects are positioned with their centres touching the sphericat surface 4 5
which is concentric with the surface 4 2. Those image segments which
form the imagery of background scenery and objects are positioned with
their centres touching the spherical surface 4 3, which is also concentric
with the surface 42. FiG. 27 B is a horizontal cross-sectional view of the
embodiment itlustrated in FIG.27 A as viewed through section A-A.
FIG.27 B shows the concentric surfaces touched by the centres of the
lenses and input image segments.
