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Claims  |
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What is claimed is:
1. A method of reducing depth distortion of a user's stereo view, of an
object present in an image on a standard television monitor while
maintaining, essentially constant, the image size and depth resolution,
said object being located in a region of interest and viewed by a pair of
image-collecting devices, with each device having an image-collecting
surface, a focal length, and a central axis from the device's
image-collecting surface to the region of interest, said method comprising
the improvement of:
converging the central axes of said image-collecting surfaces behind said
object when it is located in said region of interest; and
simultaneously increasing by equal amounts, the
collection-surface-to-object distance, the separation distance between
said devices, and the focal lengths for each of the image-collecting
devices while holding the convergence of said central axes for both of
said devices fixed on the same region of interest as it was prior to said
simultaneous increase of said distances and said focal lengths.
2. A method in accordance with claim 1 wherein said step for simultaneously
increasing said distances and said focal lengths comprises the further
step of:
moving the image-collecting devices generally laterally with respect to
said object so that the distance between the device is changed.
3. A method in accordance with claim 1 wherein the stereo view is obtained
by a right and a left image-collecting device and comprising the
additional steps of:
viewing the region of interest from a right side along the central axis of
said right image-collection device;
viewing the region of interest from a left side along the central axis of
said left image-collection device;
obtaining from said image-collecting devices, data representing the views
of said images collected by said right and left image-collecting devices;
and
alternately and synchronously projecting the data representing said views
collected by said right and said left image-collecting devices on a
television monitor so that a user's left eye sees only the data projected
on the television monitor from the left imagecollecting device and the
user's right eye sees only the data projected on the television monitor
from the right image-collecting device.
4. A method in accordance with claim 3 wherein said image on said
television monitor is presented by interlacing odd and even horizontal
television field sand wherein said projecting step further comprises the
additional steps of:
designating the data representing the view from the left image-collecting
device, arbitrarily as either the odd or the even horizontal television
field for the television monitor;
designating the data representing the view from the right image-collecting
device as the remaining horizontal television field; and
interlacing the odd and even fields on the television monitor to form a
stereo image for viewing by said user.
5. A method in accordance with claim 4 wherein said television monitor and
said stereo view thereon are within the user's limit of binocular fusion
and further wherein said projecting step further comprises:
shifting the data representing the left image to the left for presentation
in left-shifted form as one horizontal television field for said
television monitor;
shifting the data representing the right image to the right for
presentation in right-shifted form as the other horizontal television
field for said television monitor; and
further wherein said interlacing of said left-shifted and right-shifted
horizontal television fields on the television monitor forms a stereo
image within the user's limit of binocular fusion.
6. A method of reducing depth distortion and increasing depth resolution of
a user's stereo view of an image of an object located in a region of
interest as viewed by a stereo television viewing system having
overlapping views converged on said region of interest for presenting the
views on a monitoring screen, the improvement comprising the steps of:
converging a central collection axis for each of said overlapped views at a
convergence point that is located behind the object which is being viewed
and presented on said monitoring screen;
collecting each of the system's views while said axis for said system are
converged on aid convergence point; and
stereoscopically presenting the collected views on said monitor screen,
with said method being further characterized in that said monitor screen
and said stereo views presented thereon are within the viewer's limit of
binocular fusion and have an optimal depth resolution with minimal depth
distortion.
7. A system having a single television screen for presenting a stereo view
of an image by use of interlaced odd and even horizontal television field
information required to form a stereo image for said screen, the
improvement comprising:
horizontal television field storage means for storing the information which
makes up said odd and even horizontal television fields;
shifting means connected to said storage means for shifting said
information representing said odd and even fields stored in said storage
means, with said direction of shift being to the left or to the right, or
each of said fields being shifted in opposite directions; and
means for applying said shifted information representing said odd and even
fields to said television screen.
8. A system in accordance with claim 7 and further comprising:
means for obtaining a left and a right image for said stereo image; and
means connected to said image-obtaining means for converting said left and
right images to information which makes up said odd and even television
horizontal fields.
9. A system in accordance with claim 8 wherein information from a left and
a right image are assigned as said odd an even fields, and further
comprising:
means for collecting said image information; and
means for supplying said image information from said collection means to
said horizontal field storage means.
10. A system in accordance with claim 8 wherein said image collecting means
further comprises:
a pair of television image collection surfaces with each surface having a
first nodal point on an image-collection axis for said surface;
means converging both of the image-collection axes on a convergence point
which is located behind an image to be collected: and
panning means for panning the image collection surfaces about the center of
a circle which passes through the convergence point and the first nodal
point for each surface.
11. A system in accordance with claim 9 wherein said image collecting means
further comprises:
a pair of image-collection television cameras each having a central axis
for collecting a right and a left image for said stereo view; and
means directing said central axes of said cameras on said convergence
point.
12. A system in accordance with claim 11 and further wherein:
said pair of cameras are located with said central axes being parallel to
each other.
13. A system in accordance with claim 11 and further wherein:
said pair of cameras are located with said central axis for each camera
being converged on said convergence point at a distance of about one to
five meters from the camera locations.
14. A system in accordance with claim 13 and further comprising:
a zoom lens having an adjustable focal length for each of said cameras.
15. A system in accordance with claim 14 and further comprising:
means for adjusting the camera-to-image distance, the camera separation
distance and the focal lengths of said zoom lens for each camera, while
holding said convergence point for said cameras fixed as it was prior to
said adjustment.
16. A system in accordance with claim 15 wherein said increasing means
further comprises:
means for moving each of said cameras by equal amounts generally laterally
to change the distance between said cameras.
17. A stereo view image-collecting and image-presenting system having a
pair of converged left and right television cameras and a television
screen for presenting interlaced odd and even horizontal television fields
representing a left and a right image, respectively, that is collected by
the pair of cameras, viewing a region of interest said system comprising:
means for converging an image collecting axis for each of said cameras
behind the image to be collected; and
means for shifting the left camera's image to the left and the right
camera's image to the right when presented on said television screen until
said screen and said shifted images are both within the viewer's limit of
binocular fusion.
18. Apparatus for reducing depth distortion while maintaining essentially
constant, the image size and depth resolution of an image on a standard
television monitor screen, said image representing an object located in a
region of interest as viewed by a pair of image-collecting devices with
each device having an image-collecting surface, a focal length, and a
central axis to the region of interest from the device's image-collecting
surface, said apparatus comprising:
means for converging the central axes of said image-collecting surfaces
behind said object; and
means for adjusting by equal amounts, the collection-surface-to-object
distances for each image-collecting device, the separation distance
between said devices, and the focal lengths for each of the
image-collecting devices while holding the convergence point of said
central axes for both of said devices fixed on the same region of interest
as it was prior to said adjustment of said distances and said focal
lengths.
19. Apparatus in accordance with claim 18 wherein said means for
simultaneously increasing said distances and said focal lengths further
comprises:
means for moving each of the image-collecting devices rearward along said
central axes.
20. Apparatus in accordance with claim 18 wherein the stereo view is
obtained by a right and a left image-collecting device, and further
comprising:
first means for viewing the region of interest from a right side along the
central axis of said right image-collection device;
second means for viewing the region of interest from a left side along the
central axis of said left image-collection device;
means for obtaining from said image-collecting devices, data representing
the views of said images collected by said right and left image-collecting
devices; and
means for alternately and synchronously projecting the data representing
said views collected by said right and said left image-collected devices
on said television monitor screen so that a user's left eye sees only the
data projected on the television monitor screen from the left
image-collecting device and the user's right eye sees only the data
projected on the television monitor screen from the right image-collecting
device.
21. Apparatus in accordance with claim 20 wherein said image on said
television monitor screen is presented by interlacing odd and even
horizontal television fields and wherein said projecting means further
comprises:
first means for designating the data representing the view from the left
image-collecting device, arbitrarily, as either the odd or the even
horizontal television field for the television monitor screen;
second means for designating the data representing the view from the right
image-collecting device as the remaining horizontal television field; and
means for interlacing the odd and even fields on the television monitor
screen to form a stereo image for viewing by said user.
22. Apparatus in accordance with claim 21 and further comprising:
left shifting means for shifting the data representing the left image to
the left for presentation in left-shifted form as one horizontal
television field for said television monitor screen;
right shifting means for shifting the data representing the right image to
the right for presentation in the right-shifted form as the other
horizontal television field for said television monitor screen; and
further wherein
said interlacing means interlaces said left-shifted and right-shifted
horizontal television fields on the television monitor screen to form a
stereo image which is within the user's limit of binocular fusion.
23. Apparatus for reducing static depth distortion and increasing depth
resolution of a user's stereo view, on a monitoring screen, of an image of
an object located in a region of interest as viewed by a stereo television
viewing system having overlapping views converged on said object in said
region of interest, and comprising:
means for converging a central collection axis for each of said overlapped
views at a conversion point that is located behind the object which is
being viewed and presented on said monitoring screen;
means for collecting each of the system's views while said axes for said
system are converged on said conversion point; and
means for stereoptically presenting the collected views on aid monitor
screen; and
with said system being further characterized in that;
said monitor screen and said stereo views presented thereon are within the
viewer's limit of binocular fusion and have optimal depth resolution with
minimal depth distortion.
24. Apparatus for minimizing dynamic depth distortion while scanning a
region of interest with a stereo television viewing system having a
conversion point and first nodal points of two view points for the stereo
viewing system, when said system is converged on a location in a region of
interest defined by overlapping views of said stereo television viewing
system, the improvement comprising:
means for aligning said two view points along converged view-collection
axes, which intersect at said convergence point in said location of
interest; and
means for panning the stereo television viewing system about the center of
the circle which passes through the convergence point and the first two
nodal points of the two aligned view points of the stereo viewing system.
25. A system having a single television screen for presenting a stereo view
of an image by use of interlaced odd and even horizontal television field
information required to form a stereo image for said screen, the
improvement comprising:
image collection surfaces each having a first nodal point on an
image-collection axis;
means converging said image-collection axes on a convergence point behind
an image to be collected;
panning means for panning the image collection surfaces about the center of
a circle which passes through the convergence point and the first nodal
point for each surface;
means for obtaining, from said collection surfaces, a left and a right
image for said stereo view;
means connected to said image-obtaining means for converting said left and
right images from said collection surface to information which makes up
said odd and even horizontal television fields;
horizontal television field storage means for storing said television
fields information;
shifting means connected to said storage means for shifting said
information representing said odd and even fields stored in said storage
means, with said direction of shift being to the left or to the right, or
each of said fields being shifted in opposite directions; and
mean for applying said shifted information representing said odd and even
fields to said television screen.
26. A system in accordance with claim 25 wherein said system is further
defined as comprising:
a pair of television image collection surfaces with each surface having a
first nodal point on an image-collection axis for each of said surfaces;
means for converging both of said image-collection axes on said convergence
point; and
said panning means pans both of said image-collection surfaces about the
center of said circle.
27. A system in accordance with claim 26 wherein said pair of
image-collection surfaces further comprises:
a pair of image-collection television cameras, with each camera having a
central axis for collecting a right and a left image for said stereo view;
;and
means directing said central axes of said cameras on said convergence
point.
28. A system in accordance with claim 27 and further wherein:
said pair of cameras are located with said central exes being parallel to
each other.
29. A system in accordance with claim 27 and further wherein:
said pair of cameras are located with said central axis converging on said
convergence point at a distance of about one to five meters from the
camera locations.
30. A system in accordance with claim 29 and further comprising
a zoom lens having an adjustable focal length for each of said cameras.
31. A system in accordance with claim 30 and further comprising:
means for adjusting the camera-to-image distance, the camera separation
distance and the focal lengths of said zoom lenses, while holding said
convergence point for said cameras fixed as it was prior to said
adjustment.
32. A system in accordance with claim 31 where said adjusting means further
comprises:
means for moving each of said cameras generally laterally to each other in
order to change the separation distance between said cameras. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a television monitor field shifter
used in conjunction with two images, collected from different viewpoints
and transmitted, for stereoscopic reproduction, to a single monitor. More
specifically, the present invention is directed to a method of providing a
stereo image of optimal depth resolution and reduced depth distortion on a
single screen with regard to a selected region of interest that lies
within the field of view of the image-obtaining system.
2. Brief Description of the Prior Art
It is known in the prior art to display on a single screen a "composite"
image taken by a pair of video or like television cameras for the purpose
of creating a stereo image. The "composite" image displayed on the video
screen is created by alternately displaying the respective images taken by
a left and then a right camera of a camera pair. In accordance with the
past state of the art, a monitor first presents all of the odd lines of a
TV image upon the screen and next presents all of the even lines. All of
the odd and even lines collectively are called odd and even fields
respectively. In accordance with a national standard, (NTSC Standard
Television) this process is repeated thirty (30) times per second. Still
in accordance with the prior art, this standard form of picture
presentation is modified for three dimensional or "stereo" presentation of
images on a single screen, by transmitting directly from the left camera,
an image to be displayed on the screen by, e.g. the odd numbered lines,
and thereafter projecting from the right camera an image to be displayed
by the even numbered lines. A complete scan of the screen with odd and
even fields is called a "frame" and the process of alternately displaying
left and right images within a single frame is called "interlacing".
For "stereo" viewing of the interlaced left and right images a human
observer must view the left image with his left eye and the right image
with his right eye. One method of accomplishing this is by viewing the
screen through a state-of-the-art liquid crystal stereo viewer which opens
and closes light shutters in front of the eyes. The operation of the
shutters in the stereo viewer is synchronized with the image being
presented on the monitor so that the left eye sees the screen when the odd
lines are displayed and the right eye sees the screen when the even lines
are displayed.
The foregoing is accomplished in the prior art in connection with a
substantially standard (cathode ray tube or the like) video screen for
displaying the images taken by the left and right cameras. The left and
rights fields, representative of image information, from the left and
right cameras are applied to a switching box, which box interlaces the two
fields to form each frame on the monitor.
Remote monitoring and control of objects, such as remote manipulation and
control of equipment and robots has developed a need for an improved
stereo control system. It will be readily appreciated by those skilled in
the art that accurate stereo viewing of a remote site is especially
important for remote manipulation of robots. Such applications may be
required, for example, while working in outer space, underwater, or in
nuclear facilities, to list some typical tasks.
A search of the prior art has developed several patents of interest to the
application.
U.S. Pat. No. 4,647,965 to Imsand discloses a method for improving the
viewing comfort of three dimensional images, including the shifting of
images of objects, so that the object images on the screen are within the
viewer's limit of binocular fusion. As a result of the shifting, the
viewer does not see double images. Although the system of this patent is
acceptable for entertainment purposes, it is not of significant value for
remote control purposes, and one following the Imsand disclosure will
create depth errors by visually changing an object's perceived depth.
U.S. Pat. No. 4,399,456 to Zalm suggests a device for shifting the left
image in a three dimensional television display so that the viewer does
not see scene information from the side edges of the screen. It is
questionable whether any image shifting actually occurs, but assuming that
there is image shifting, such shifting is restricted in that the left
image can only be shifted to the right, and the right image can not be
shifted at all. The extent of the shifting is no more than approximately
six percent (6%) of the picture width.
U.S. Pat. No. 4,677,468 to Moroshita discloses a system wherein the images
of two TV monitors are projected with optical lenses upon a single
non-electric viewing screen. A device shifts the timing of the readout of
the left eye frame memory and of the right eye frame memory with respect
to each other, for the purpose of allowing the viewer to select an
observation point different from that of the camera. Frames and not fields
are shifted by Moroshita and there is not mention of the problem nor
solution for depth distortion in this reference. Moreover, applicant's
invention is directed to a TV monitor screen field shifter used to
horizontally shift all possible combinational directions of two fields to
be interlaced on the TV monitor screen. Moroshita does not teach or
suggest applicant's invention.
For still further background to the present invention, reference is made to
U.S. Pat. Nos. 3,959,580 and 3,598,032 (Chocol et al and Bohn et al).
In performing and reporting on the experiments that led to the development
of this invention, the inventor has reported on some of the approaches
discussed in the literature relative to stereo imaging. The report of the
experimentation of which the inventor is the primary author, is entitled
"Stereo Depth Distortions in Teleoperation." By Daniel B. Diner and Marika
von Sydow, dated Feb. 1, 1987 JPL publication 87-1. That report ("Diner
Report") is incorporated herein by reference.
As discussed in the Diner Report, camera configurations which are similar
to natural human viewing conditions are called orthostereoscopic;
unnaturally wide camera separation configurations are called
hyperstereoscopic. In the literature on stereo imaging, some researchers
advocate orthostereoscopic camera alignments, and other researchers
advocate hyperstereoscopic camera alignment.
Shields, Kirkpatrick, Malone and Huggins, "Desing Parameters for a
Stereoptic Television System Based on Direct Depth Perception Cues,"
Washington, D.C.: Proceedings of the Human Factors Society 19th Annual
Meeting, (1975), pp. 423-427, found no gain in performance with
hyperstereopsis on a stereo depth comparison task, and recommended
orthostereopsis. This recommendation is not surprising as the depth
distortion of hyperstereopsis may well have overridden the advantage of
the increased depth resolution.
Grant, Meirick Polhemus, Spencer, Swain, and Tewell, "Conceptual Design
Study for a Teleoperator Visual System Report," Denver, Co: Martin
Marietta Corporation Report NASA CR-124273, (April 1973), found no gain in
performance with hyperstereopsis on a peg-in-hole task and recommended
orthostereopsis. A peg-in-hole task requires high depth percision only in
a small region of the work space. The depth distortion of hyperstereopsis
only becomes significant for objects which are separated horizontally.
Thus the performance of the insertion of the peg into the hole should
increase with the increased depth resolution of hyperstereopsis. Perhaps
the depth distortions hurt the performance of the long range motions (such
as moving towards the peg and moving the peg towards the hole) enough to
overshadow the increase in performance of the insertions.
Upton and Strother, "Design and Flight Evaluation of a Helmet-mounted
Display and Control System," In Birt, J. A. & Task, H. L. (Eds.), A
symposium on visually coupled systems: Development and application
(AMD-TR-73-1), Brooks Air Force Base, TX, (September, 1973), reported that
hyperstereopsis greatly enhanced depth detection of camouflaged buildings
from helicopter-mounted stereo camera. This result is expected. The
critical point to be noted is that the accurate detection of depth is a
different phenomenon from the accurate estimate of the magnitude of a true
depth. Hyperstereopsis artificially magnifies the perceived magnitude of a
true depth difference, making that depth difference easier to detect, but
much harder to perform accurate teleoperation upon. For example,
hyperstereopsis might make a one-story camouflaged building appear to be
four stories tall.
Zamarian, "Use of Stereopsis in Electronic Displays: Part II--Stereoscopic
Threshold Performance as a Function of System Characteristics," Douglas
Aircraft Company Report MDC J7410, (December, 1976), reported that
hyperstereopsis improved performance over orthostereopsis on a three-bar
depth adjustment ask, using converged cameras. The three-bar depth
adjustment task insures that the depth distortions will play a role in his
experiment. He states, ". . . it was found that performance improved with
increasing [camera] separation but at a decreasing rate of improvement."
It is suspected that he was experiencing a trade-off between increased
resolution and distortion.
Pepper, Cole, and Spain, "The Influence of Camera Separation and Head
Movement on Perceptual Performance Under Direct and TV-displayed
Condition," Proceedings of the Society for Information Display, 24,
(1983), pp. 73-80, reported that hyperstereopsis improved performance on a
two-bar depth adjustment task. They used parallel camera configurations,
and therefore introduced no stereo depth distortions. Such results,
therefore, do not compare directly to the invention presented in this
application, nor do the results teach or suggest the invention.
Spain, "A Psychophysical Investigation of the Perception of Depth with
Stereoscopic Television Displays," University of Hawaii doctoral
dissertation, (May 1984), reported that hyperstereopsis improved
performance on a two-bar depth adjustment task. He converged the cameras
so that the camera convergence point was half-way between the two bars
when the bars were located at equal depth. It is felt that each bar
experience the same depth distortion. The net effect then would have been
that the relative distortion between the two bars cancelled out. In that
case, the increased stereo depth resolution of hyperstereopsis would have
improved performance.
Bejczy, "Performance Evaluation of Computer-aided Manipulator Control."
IEEE International Conference on Systems, Man and Cybernetics, (1976),
reported surprisingly poor performance with a stereo TV viewing system of
a task which required the positioning and orienting of an end-effector in
an almost static visual scene. Operators were required to pick up one
block and place it upon another block. Although the thrust of this work
was to evaluate the effect of short-range proximity sensors in conjunction
with mono and stereo camera systems on the performance of this task, the
surprisingly poor performance with stereo viewing must be noted.
In reviewing the literature, it was noticed that most analyses of stereo TV
viewing use small angle approximations. However, I have discovered that
the actual stereo distortion of the fronto-parallel plane of convergence
is such that small angle approximations obscure the relationship between
this distortion and the key parameters of the camera configurations.
The above-noted prior art patents that disclose stereo systems for
entertainment are aimed primarily at viewer comfort and are not useful for
the critical tasks of teleoperation. The literature discussed above and
the known patents applicable to teleoperation (Morishita) do not appear to
have perceived that the visual depth distortion and depth resolution
varies within the field of view of the cameras. Additionally the use of
small angle approximations by the prior art study approaches has obscured
valuable parameters concerning depth distortion and depth resolution. This
invention discloses and claims horizontal field shifting for a TV monitor
image and a stereo image presentation technique on a standard TV monitor
which increases depth resolution while decreasing depth distortion, thus
solving the resolution/distortion trade-off.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method whereby
operators who are interested in high-precision depth views of remote
locations, perhaps to control robots, machinery or perform like tasks,
with the assistance of video views gained by converged remote viewpoints,
can perform high precision depth tasks and/or judgments with minimal
interference due to stereo depth distortion.
It is another object of the present invention to provide in a remote
monitoring system using two video viewpoints and a single video display, a
method for obtaining, with regard to an accurate region of interest in the
stereoscopically viewed space, optimal depth resolution with relatively
minimal depth distortion.
The foregoing and other objects and advantages are attained by a method
which in a remote viewing system utilizes a right video viewpoint and a
left video viewpoint having respective fields of view which overlap in
part with both views being transmitted to a single video display screen.
Method and apparatus horizontally shift the odd and even fields,
representing the views, for interlacing in shifted form on a single
monitor screen for stereoscopic viewing.
In accordance with the method of the invention, a region of interest is
selected in the stereoscopically viewed space, the region being one
wherein optimal stereo viewing, and therefore maximal stereo depth
resolution and minimal stereo depth distortion are desired. The video
viewpoints act as image collection locations which have central axes that
are purposely converged behind the region of primary interest to an
operator viewing the monitor screen. (Parallel cameras are understood to
converge at infinity and thus are included in the above-mentioned camera
configuration.) Data representative of the images obtained by the left and
right viewpoints are transmitted for application to a single video TV
monitor screen. One field each of the images of the left and right
viewpoints are alternatively displaced and interlaced in a known manner
for stereo viewing on the monitor. The views of the screen by the left eye
and right eye of an observer are blocked alternatively and synchronously
with the projection of the left and right viewpoint field images so that
the viewer sees the left viewpoint's image only with his left eye, an the
right viewpoint's image only with his right eye. The images of the left
and right viewpoints are electronically shifted (left image to the left,
right image to the right) on the video screen such that the TV monitor
screen and the two images presented thereon are within the viewer's limit
of binocular fusion. Consequently, optimal stereo resolution and minimal
stereo depth distortion is attainable on a standard TV monitor screen with
regard to objects at or in front of the selected region.
In accordance with the invention, a human observer, such as an operator of
remotely controlled equipment, is able to utilize the remote viewing
system to direct and follow the performance of tasks with optimal stere
depth resolution and low stereo depth distortion.
The features of the present invention can be best understood together with
further objects and advantages by reference to the following description,
taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the field of view of converged
stereo viewpoints;
FIG. 2 is a block-diagramatic representation of an understanding of the
process of the present invention;
FIG. 3 is a schematic representation of the geometry of a converged camera
stereo system;
FIG. 4 is a presentation useful in promoting an understanding of depth
distortion;
FIG. 5 is a diagram useful in promoting an understanding of minimization of
dynamic depth distortion in accordance with the principles of the
invention;
FIG. 6 is a block diagram of apparatus and a method of horizontal field
shifting;
FIG. 7 is a diagram useful in promoting an understanding of minimization of
static depth distortion in accordance with the principles of the
invention; and
FIG. 8 is a diagram useful in promoting an understanding of the
minimization of dynamic depth distortion in accordance with the principles
of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The embodiment of the invention disclosed herein is the best mode
contemplated by the inventor for carrying out his invention, although it
should be understood that various modifications can be accomplished within
the parameters of the present invention.
Referring now to the drawings and particularly to FIG. 1, the fields of
view of two converged television monitoring cameras are shown
schematically. At this point it should be understood that the two cameras
may be replaced by any suitable combination of image collection devices.
The description of two cameras is for ease of understanding only, since
the invention in its broadest concept involves merely a source of image
collection view surfaces which are displayed as video images. The cameras
have variable focus such as is provided by a zoom lens. For simplicity
purposed, the term "cameras" will be described and used herein, rather
continually referring to the more cumbersome term "image collection view
surfaces".
More specifically, in its stationary position indicated on FIG. 1, a left
television or video camera 20 views a region of space, which is defined by
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