Image analysis – Applications – 3-d or stereo imaging analysis
Reexamination Certificate
1998-06-01
2001-03-20
Mehta, Bhavesh (Department: 2621)
Image analysis
Applications
3-d or stereo imaging analysis
C348S042000, C382S232000
Reexamination Certificate
active
06205241
ABSTRACT:
FIELD OF INVENTION
This invention pertains to the field of image compression. More specifically, this invention pertains to a range based method of compressing a stereoscopic set of images.
BACKGROUND OF THE INVENTION
Stereoscopic photography has been practiced since almost the beginning of photography itself. Early stereoscopic viewers allowed users to view scenic locations with a realism lacking in ordinary photography. Modern versions of stereoscopic viewers, such as the View-Master, produced by Tyco Toys, have long been staples of the toy industry. Advances in technology have produced such variations as “3-D” movies and, more recently, “virtual reality,” or computer generated interactive stereoscopic simulations. As real-time stereoscopic viewers are beginning to find uses in such areas as the medical field, it is apparent that stereoscopic viewing is becoming more common.
The optical phenomenon exploited by the brain to extract depth information from a three dimensional scene is known as “parallax.” As shown in
FIG. 1
, a person with two functional eyes
402
viewing point
304
sees slightly different images in each eye
402
, due to the slightly different angle from each eye
402
to point
304
. The apparent location of point
304
is different in each image formed by eyes
402
. By analyzing the differences due to parallax, the brain is able to determine the distance to point
304
. By photographing, or otherwise recording, a scene from two distinct locations which mimic the location of eyes
402
, as illustrated in
FIG. 2
, a set of images can be generated which, when viewed properly, can recreate the parallax of the original scene, giving the illusion of three dimensions in the two dimensional images. Each camera
202
uses a lens or lens system
204
to project an image of point
304
onto image plane
308
. As illustrated in
FIGS. 3
a
and
3
b,
each image point
302
of images
300
a
and
300
b
represents a point
304
in a three dimensional scene. Each image
300
is associated with a “vantage point”
306
, which is the location of the point of view of that image
300
. Each image point
302
corresponds to the intersection of an image plane
308
with a “view line”
310
. A view line
310
passes through a vantage point
306
and the point
304
in the scene which is represented by image point
302
. The view line
310
which passes through a vantage point
306
and intersects image plane
308
perpendicularly defines a “center point”
312
in the image
300
associated with the vantage point
306
.
A set of two or more images
300
is “stereoscopic” if they represent substantially parallel views of substantially the same scene, with the vantage points
306
of the images
300
being separated in a direction substantially perpendicular to the direction of the views, this perpendicular direction defining the “epipolar” axis
314
.
As illustrated in
FIG. 4
, when stereoscopic images
300
are viewed with eyes
402
taking the place of vantage points
306
relative to images
300
, a viewer perceives apparent points
404
where points
304
had been. Apparent points
404
appear to be at a distance
416
which is proportional to the actual distance
316
of points
304
, scaled by the ratio of distance
418
to distance
318
, and the ratio of distance
420
to distance
320
. Distance
420
is the distance between each of the viewer's eyes
402
, and distance
320
is the distance between vantage points
306
. Distance
418
is the distance between the viewer's eyes
402
and images
300
, and distance
318
is the distance between vantage points
306
and image plane
308
.
Stereoscopic systems require the use of at least two stereoscopic images
300
to create the illusion of three dimensional apparent points
404
. Graphic images typically contain a large amount of information. Because of this, the storage and transmission of graphic images generally benefit from the use of compression techniques which reduce the amount of information necessary to reconstruct an image. A compressed graphics file contains less information than an uncompressed image, but it can be used to recreate, either perfectly or with losses, the uncompressed image. Because multiple graphic images are required by stereoscopic systems, the image storage and transmission requirements of such systems are twice the image storage and transmission requirements of ordinary monocular images. As such, stereoscopic systems are especially prone to benefit from image compression techniques. What is needed is an image compression technique which is especially suited to stereoscopic images, taking advantage of the high level of redundancy in stereoscopic image sets.
SUMMARY OF THE INVENTION
In one embodiment, the present invention comprises a method for compressing a set of stereoscopic images (
300
). For at least one of the apparent points (
404
) represented in the set of stereoscopic images (
300
), a region (
502
) which represents at least the apparent point (
404
) is identified in each image (
300
). The locations of these regions (
502
) within the images (
300
), together with the geometry of the vantage point (
306
) locations relative to image plane (
308
), specify the apparent depths (
416
) of the apparent points (
404
) in the scene. Information relating to the apparent depths (
416
) is recorded for the apparent points (
404
). This recorded depth information, together with just one of the stereoscopic images (
300
), can be used to later reconstruct the other stereoscopic image (
300
) for stereoscopic viewing.
The set of stereoscopic images (
300
) can be still images or moving images, and they can be captured digitally, scanned from photographs, or computer-generated.
REFERENCES:
patent: 3769889 (1973-11-01), Wechsler
patent: 3883251 (1975-05-01), Helava
patent: 4601053 (1986-07-01), Grumet
patent: 5249035 (1993-09-01), Yamanaka
patent: 5347363 (1994-09-01), Yamanaka
patent: 5390024 (1995-02-01), Wright
patent: 5432712 (1995-07-01), Chan
patent: 5455689 (1995-10-01), Taylor et al.
patent: 5475422 (1995-12-01), Mori et al.
patent: 5495576 (1996-02-01), Ritchey
patent: 5510831 (1996-04-01), Mayhew
patent: 5644651 (1997-07-01), Cox et al.
patent: 5655033 (1997-08-01), Inoguchi et al.
patent: 5680474 (1997-10-01), Iijima et al.
patent: 5703961 (1997-12-01), Rogina et al.
patent: 5852672 (1998-12-01), Lu
patent: 5973726 (1999-10-01), Iijima et al.
patent: 10-32840 (1998-02-01), None
Zhizhuo, W., “From Photogrammetry to Geomatics—a Commemoration of the Accomplishment that is VirtuoZo”, The VirtuoZo Manuscript, http://www.squirrel.com.au/virtuozo/Manuscript/wang/html, Dec. 18, 1997, Australia.
Roux, M., “Cartography Updating”, http://www-ima.enst.fr/activite_96/en
ode42.html, Mar. 24, 1998, France.
Dupéret. A., “Automatic Derivation of a DTM to Produce Countour Lines”, http://dgrwww.epfl.ch/PHOT/publicat/wks96/Art_3_2.html, Mar. 24, 1998, France.
Bayat Ali
Canon Kabushiki Kaisha
Fenwick & West LLP
Mehta Bhavesh
LandOfFree
Compression of stereoscopic images does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compression of stereoscopic images, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compression of stereoscopic images will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2497999