STEREOSCOPIC VIEWING APPARATUS
The present invention relates to a viewing apparatus for producing a
stereoscopic image from video images.
Various optical magnifying apparatus exist for producing stereoscopic images,
such as disclosed in the applicant's earlier WO-A- 1994/006048.
Various displays also exist for displaying three-dimensional video images,
but, in requiring modification of the images, such as polarized or synchronized
images, the observer is required to use adapted eyewear, and the resulting
image as observed by the observer suffers from reduced resolution and/or
lower refresh rates.
It is an aim of the present invention to provide a viewing apparatus which
produces a stereoscopic image from video images, and which does not require
the use of adapted eyewear.
I n one aspect the present invention provides a viewing apparatus for
producing a stereoscopic image for an observer, the viewing apparatus
comprising : first and second video projectors for projecting respective ones
of first and second video images of an object, the first and second images
being different images which are one or both of spatially and angularly shifted
in relation to the object so as to convey parallax between the images; a mirror
arrangement comprising a concave mirror which receives light from the first
and second video projectors, the mirror arrangement being located in relation
to the first and second video projectors such that focussed images of the
object are produced at the mirror arrangement; and a viewing lens for
relaying exit pupils corresponding to each of the focussed images as reflected
by the mirror arrangement to a viewing plane so as to be viewable at the
respective eyes of the observer as a stereoscopic image without use of
adpated eyewear; wherein the video projectors comprise first and second
video displays which are driven by first and second video signals to display
respective ones of the first and second video images, and first and second
optical arrangements for focussing light from the respective images as
displayed by the first and second displays to the mirror arrangement.
In one embodiment optical axes of the displays are co-axial, with the displays
optionally being in opposing relation.
In another embodiment optical axes of the displays enclose an acute angle.
In one embodiment the video signals are provided from three-dimensional
modelling or animation systems.
In one embodiment the optical arrangement comprises at least one lens and
at least one mirror for directing an optical light path from the display to the
mirror arrangement.
In one embodiment the images are spatially shifted images of the object.
In one embodiment the images are angularly shifted images of the object.
In one embodiment the images are spatially and angularly shifted images of
the object.
In one embodiment the images are magnified images of the object.
In one embodiment the mirror arrangement comprises a single concave
mirror.
In one embodiment the apparatus further comprises: processing circuitry for
manipulating the images as projected by the video projectors to remove or
accommodate at least one artefact arising from an optical structure of the
apparatus.
In one embodiment the at least one artefact includes keystone distortion.
In another aspect the present invention provides a viewing apparatus for
producing a stereoscopic image for an observer, the viewing apparatus
comprising : first and second video projectors for projecting respective ones
of first and second video images of an object, the first and second images
being different images which are one or both of spatially and angularly shifted
in relation to the object so as to convey parallax between the images; a mirror
arrangement which receives light from the first and second video projectors,
the mirror arrangement being located in relation to the first and second video
projectors such that focussed images of the object are produced at the mirror
arrangement; and a viewing lens for relaying exit pupils corresponding to
each of the focussed images as reflected by the mirror arrangement to a
viewing plane so as to be viewable at the respective eyes of the observer as
a stereoscopic image.
In a further aspect the present invention provides a stereoscopic microscope
incorporating the above-described viewing apparatus.
In yet another aspect the present invention provides a stereoscopic
microscope, comprising : the above-described viewing apparatus; and first
and second video cameras for capturing respective ones of first and second
magnified images of the object.
In one embodiment the microscope further comprises: an objective lens
arrangement for producing first and second magnified images of the object,
the first and second video cameras being configured to capture respective
ones of first and second magnified images of the object from the image as
produced by the objective lens arrangement.
In one embodiment the objective lens arrangement comprises first and
second zoom objectives, each for producing a magnified image of the object,
the first and second video cameras being configured to capture respective
ones of first and second magnified images of the object from the image as
produced by the zoom objectives.
In one embodiment optical axes of the zoom objectives enclose an acute
angle which corresponds to a viewing angle between the eyes of the observer
to the mirror arrangement.
Preferred embodiments of the present invention will now be described
hereinbelow by way of example only with reference to the accompanying
drawings, in which :
Figure 1(a) illustrates a stereoscopic viewing apparatus in accordance with a
first embodiment of the present invention;
Figure 1(b) illustrates a partial side view of the viewing apparatus of Figure
1(a), illustrating the angular relationship between the incident and reflected
light paths at the mirror arrangement in the vertical sense;
Figures 2(a) to (c) illustrate perspective, side and front views of a
stereoscopic viewing apparatus in accordance with a second embodiment of
the present invention;
Figure 3 illustrates a stereoscopic viewing apparatus in accordance with a
third embodiment of the present invention; and
Figure 4 illustrates a stereoscopic viewing apparatus in accordance with a
fourth embodiment of the present invention; and
Figures 1(a) and (b) illustrate a stereoscopic viewing apparatus in accordance
with a first embodiment of the present invention.
The viewing apparatus comprises an objective lens arrangement 3 for
producing first and second magnified images of an object located at an object
plane OP, in this embodiment as defined by an aperture stop 5.
I n this embodiment the objective lens arrangement 3 comprises first and
second zoom objectives 4a, b which each comprise an objective lens 7 and
additional lenses 9, 11, which provide for control of magnification by altering
the relative positions of the additional lenses 9, 11 in relation to the objective
lens 7.
I n this embodiment the optical axes of the zoom objectives 4a, b are arranged
in converging relation, such as to provide for parallax between the produced
images of the object.
In one embodiment the optical axes of the zoom objectives 4a, b enclose an
acute angle which corresponds to the viewing angle between the eyes to a
mirror arrangement 35, as will be described in more detail hereinbelow.
The viewing apparatus further comprises first and second video cameras 15a,
b which each include a sensor 19 for capturing respective ones of the first
and second magnified images of the object, which images are spatially or
angularly shifted in relation the object, such that, when the corresponding
exit pupils are presented to respective ones of the left and right eyes of an
observer, as will be described in more detail hereinbelow, the perceived
image is a three-dimensional image.
The viewing apparatus further comprises image projectors 20a, b which
project focussed images at a mirror arrangement 35 of light from the
respective magnified images of the object as captured by the first and second
video cameras 15a, b.
In this embodiment the image projectors 20a, b each comprise a display 2 1
which is driven to display a respective one of the first and second magnified
images of the object as captured by the first and second video cameras 15a,
b, and an optical arrangement 25 for providing a focussed image at a mirror
arrangement 35 of light from the magnified images as displayed by the
respective display 21 of the image projectors 20a, b.
I n this embodiment the display 21 comprises a high definition (HD) video
display, optionally an ultra-high definition (UHD) display.
I n this embodiment the displays 21 of the image projectors 20a, b are
disposed with a co-axial arrangement, here in opposing relation. I n
alternative embodiments the displays 21 could have any angular or spatial
relationship.
I n this embodiment each optical arrangement 25 comprises at least one lens
29 which provides for the focussed image, and at least one mirror 31 which
directs the optical path from the respective display 21 to the mirror
arrangement 35.
The viewing apparatus further comprises a mirror arrangement 35 which
receives light from each of the images as presented by the displays 21 of the
image projectors 20a, b, the mirror arrangement 35 being located such that
focussed magnified images of the object are produced at the mirror
arrangement 35, and light received by the mirror arrangement 35 is reflected
to a viewing lens 37.
I n this embodiment the mirror arrangement 35 comprises a concave mirror,
here formed as a single mirror, at which focussed or real images of the object
are superimposed, and the radius of the mirror is selected such that the exit
pupils of the lenses 29 of the optical arrangements 25 of the respective image
projectors 20a, b are relayed to the eyes of the observer at a viewing plane
VP, as will be described further hereinbelow.
In an alternative embodiment the mirror arrangement 35 could comprise a
planar or aspherical mirror and a spherical lens at the surface of the mirror.
The viewing apparatus further comprises a viewing lens 37 for relaying the
exit pupils corresponding to each of the images as received by the mirror
arrangement 35, to a viewing plane VP, such as to be viewable at the
respective eyes of an observer as a stereoscopic image.
The present inventors have found surprisingly that the detail of the observed
three-dimensional image is far greater than the detail as would be expected
from the "sum" of the detail in the first and second images.
I n addition, the present invention enables the video signals to be recorded
and presented subsequently as still or moving video.
Figures 2(a) to (c) illustrate a stereoscopic viewing apparatus in accordance
with a second embodiment of the present invention.
The viewing apparatus of this embodiment is very similar to the viewing
apparatus of the first-described embodiment. In order to avoid unnecessary
duplication of description, only the differences will be described in detail, with
like parts being designated by like reference signs.
The viewing apparatus of this embodiment differs from that of the firstdescribed
embodiment in that the optical axes of the displays 21 of the image
projectors 20a, b are not co-axial but enclose an acute angle, and in that the
optical arrangements 25 of the image projectors 20a, b each comprise a
plurality of lenses 29a, b and a plurality of mirrors 31a, b, with one of the
mirrors 31b being common to each of the optical arrangements 25.
Figure 3 illustrates a stereoscopic viewing apparatus in accordance with a
third embodiment of the present invention.
The viewing apparatus of this embodiment is very similar to the viewing
apparatus of the first-described embodiment. In order to avoid unnecessary
duplication of description, only the differences will be described in detail, with
like parts being designated by like reference signs.
The viewing apparatus of this embodiment differs from that of the firstdescribed
embodiment in that the optical axes of the zoom objectives 4a, b
are arranged in parallel, spaced relation, and share a common, converging
objective lens 7, such as to provide for parallax between the produced images
of the object.
Figure 4 illustrates a stereoscopic viewing apparatus in accordance with a
fourth embodiment of the present invention.
The viewing apparatus of this embodiment is very similar to the viewing
apparatus of the first-described embodiment. In order to avoid unnecessary
duplication of description, only the differences will be described in detail, with
like parts being designated by like reference signs.
The viewing apparatus of this embodiment differs from that of the firstdescribed
embodiment in further comprising a beam splitter 51 which is
disposed on the optical axis between the mirror arrangement 35 and the
viewing lens 37 to receive light from the mirrors 31 of the optical
arrangements 25 of the first and second projectors 20a, b, which are disposed
in orthogonal relation to the beam splitter 51. As will be seen, this
arrangement removes the angular component between the incident and
reflected light paths at the mirror arrangement 35 as present in the firstdescribed
embodiment, and consequentially, image distortion, arising from
angular projection onto a flat surface as in the first-described embodiment,
is much reduced, albeit with reduced light intensity.
In this embodiment the beam splitter 51 is a prismatic cube, but could
alternatively be a semi-reflective mirror.
Finally, it will be understood that the present invention has been described in
its preferred embodiments and can be modified in many different ways in
accordance with the scope of the invention as defined by the appended
claims.
For example, although the first and second video images as displayed by the
displays 21 of the video projectors 20a, b are derived from a zoom objective
arrangement in the first-described embodiment, the displays 21 could
alternatively be driven by other video signals, such as provided by modelling
or animation systems, for example, 3D CAD modelling systems, with the
video signals being provided from views having an angular and/or spaced
relation.
In one embodiment processing circuitry can be employed to manipulate the
images as displayed by the displays 21 of the video projectors 20a, b, in order
to accommodate artefacts arising from the optical structure, such as the
keystone distortion, which arises from angular projection onto a flat surface.
CLAIMS
1. A viewing apparatus for producing a stereoscopic image for an
observer, the viewing apparatus comprising :
first and second video projectors for projecting respective ones of first
and second video images of an object, the first and second images
being different images which are one or both of spatially and angularly
shifted in relation to the object so as to convey parallax between the
images;
a mirror arrangement comprising a concave mirror which receives light
from the first and second video projectors, the mirror arrangement
being located in relation to the first and second video projectors such
that focussed images of the object are produced at the mirror
arrangement; and
a viewing lens for relaying exit pupils corresponding to each of the
focussed images as reflected by the mirror arrangement to a viewing
plane so as to be viewable at the respective eyes of the observer as a
stereoscopic image without use of adapted eyewear;
wherein the video projectors comprise first and second video displays
which are driven by first and second video signals to display respective
ones of the first and second video images, and first and second optical
arrangements for focussing light from the respective images as
displayed by the first and second displays to the mirror arrangement.
2. The apparatus of claim 1, wherein optical axes of the displays are co
axial, with the displays optionally being in opposing relation.
3. The apparatus of claim 1, wherein optical axes of the displays enclose
an acute angle.
4 The apparatus of any of claims 1 to 3, wherein the video signals are
provided from three-dimensional modelling or animation systems.
5. The apparatus of any of claims 1 to 4, wherein the optical arrangement
comprises at least one lens and at least one mirror for directing an
optical light path from the display to the mirror arrangement.
6. The apparatus of any of claims 1 to 5, wherein the images are spatially
shifted images of the object.
7. The apparatus of any of claims 1 to 5, wherein the images are angularly
shifted images of the object.
8 The apparatus of any of claims 1 to 5, wherein the images are spatially
and angularly shifted images of the object.
9. The apparatus of any of claims 1 to 8, wherein the images are
magnified images of the object.
10. The apparatus of any of claims 1 to 9, wherein the mirror arrangement
comprises a single concave mirror.
11. The apparatus of any of claims 1 to 10, further comprising :
processing circuitry for manipulating the images as projected by the
video projectors to remove or accommodate at least one artefact
arising from an optical structure of the apparatus.
12. The apparatus of claim 11, wherein the at least one artefact includes
keystone distortion.
13. A stereoscopic microscope incorporating the viewing apparatus of any
of claims 1 to 12.
14. A stereoscopic microscope, comprising :
the viewing apparatus of any of claims 1 to 12; and
first and second video cameras for capturing respective ones of first
and second magnified images of the object.
15. The microscope of claim 14, further comprising :
an objective lens arrangement for producing first and second magnified
images of the object, the first and second video cameras being
configured to capture respective ones of first and second magnified
images of the object from the image as produced by the objective lens
arrangement.
16. The microscope of claim 15, wherein the objective lens arrangement
comprises first and second zoom objectives, each for producing a
magnified image of the object, the first and second video cameras
being configured to capture respective ones of first and second
magnified images of the object from the image as produced by the
zoom objectives.
17. The microscope of claim 16, wherein optical axes of the zoom
objectives enclose an acute angle which corresponds to a viewing angle
between the eyes of the observer to the mirror arrangement.