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United States Patent6459451
Driscoll, Jr. , ; et al.October 1, 2002
Title
Method and apparatus for a panoramic camera to capture a 360 degree image
Abstract
Most camera systems only record an image from a limited viewing angle. A new panoramic camera apparatus is disclosed that instantaneously captures a 360 degree panoramic image. In the camera device, virtually all of the light that converges on a point in space is captured. Specifically, in the camera of the present invention, light striking this point in space is captured if it comes from any direction, 360 degrees around the point and from angles 50 degrees or more above and below the horizon. The panoramic image is recorded as a two dimensional annular image. Furthermore, various different systems for displaying the panoramic images and distributing the panoramic images. Specifically, methods and apparatus for digitally performing a geometric transformation of the two dimensional annular image into rectangular projections such that the panoramic image can be displayed using conventional methods such as printed images and televised images.
Inventors:Driscoll, Jr.; Edward (Portola Valley, CA), Morrow; Howard  (San Jose, CA), Steinhauer; Alan J.  (Sunnyvale, CA), Lomax; Willard Curtis  (Sunnyvale, CA)
Assignee:Be Here Corporation (Cupertino, CA)
Appl. No.:872525
Filed:June 11, 1997
Current U.S. Class:348/335 348/36 359/727 
Field of Search:348/207,335,336,337,339,340,343,344 359/363,364,365,366,367,725,726,727,728,402,403,404,405,406
U.S. Patent Documents
2146662February 1939Van Albada
2244235June 1941Ayres
2304434December 1942Ayres
2628529February 1953Braymer
2654286October 1953Cesar
3203328August 1965Brueggemann
3205777September 1965Brenner
3229576January 1966Rees
3692934September 1972Herndon
3723805March 1973Scarpino et al.
3785715January 1974Mecklenborg
3832046August 1974Mecklenborg
3846809November 1974Pinzone et al.
3872238March 1975Herndon
3934259January 1976Krider
3975095August 1976Minoura et al.
4012126March 1977Rosendahl et al.
4017145April 1977Jerie
4038670July 1977Seitz
4058831November 1977Smith
4078860March 1978Globus et al.
4103990August 1978Yamada
4157218June 1979Gordon et al.
4190866February 1980Luknar
4241985December 1980Globus et al.
4326775April 1982King
4395093July 1983Rosendahl et al.
4429957February 1984King
4463380July 1984Hooks, Jr.
4484801November 1984Cox
4549208October 1985Kamejima et al.
4561733December 1985Kreischer
4566763January 1986Greguss
4578682March 1986Hooper et al.
4593982June 1986Rosset
4602857July 1986Woltz et al.
4656506April 1987Ritchey
4661855April 1987Gulck
4670648June 1987Hall et al.
4728839March 1988Coughlan et al.
4736436April 1988Yasukawa et al.
4742390May 1988Francke et al.
4751660June 1988Hedley
4754269June 1988Kishi et al.
4761641August 1988Schreiber
4772942September 1988Tuck
4835532May 1989Fant
4858002August 1989Zobel
4858149August 1989Quarendon
4864335September 1989Corrales
4868682September 1989Shimizu et al.
4901140February 1990Lang et al.
4907084March 1990Nagafusa
4908874March 1990Gabreil
4918473April 1990Blackshear
4924094May 1990Moore
4943821July 1990Gelphman et al.
4943851July 1990Lang et al.
4945367July 1990Blackshear
4965844October 1990Oka et al.
4974072November 1990Hasegawa
4985762January 1991Smith
5016109May 1991Gaylord
5021813June 1991Corrales
5023725June 1991McCutchen
5038225August 1991Maeshima
5040055August 1991Smith
5048102September 1991Tararine et al.
5067019November 1991Juday et al.
5068735November 1991Tuchiya et al.
5077609December 1991Manephe
5083389January 1992Alperin
5097325March 1992Dill
5115266May 1992Troje
5130794July 1992Ritchey
5142354August 1992Suzuki et al.
5153716October 1992Smith
5166878November 1992Poelstra
5173948December 1992Blackham et al.
5175808December 1992Sayre
5185667February 1993Zimmerman
5187571February 1993Braun et al.
5189528February 1993Takahima et al.
5200818April 1993Neta et al.
5231673July 1993Elenga
5259584November 1993Wainwright
5262852November 1993Eouzan et al.
5262867November 1993Kojima
5283819February 1994Glick et al.
5289312February 1994Hashimoto et al.
5305035April 1994Schonherr et al.
5313306May 1994Kuban et al.
5315331May 1994Ohshita
5341218August 1994Kaneko et al.
5359363October 1994Kuban et al.
5384588January 1995Martin et al.
5396583March 1995Chen et al.
5422987June 1995Yamada
5432871July 1995Novik
5446833August 1995Miller et al.
5471346November 1995Ames
5473474December 1995Powell
5479203December 1995Kawai et al.
5490239February 1996Myers
5495576February 1996Ritchey
5502592March 1996Jamieson
5508734April 1996Bake et al.
5539483July 1996Nalwa
5550646August 1996Hassen et al.
5563650October 1996Poelstra
5601353February 1997Naimark et al.
5606365February 1997Maurinus et al.
5612533March 1997Judd et al.
5627675May 1997Davis et al.
5631778May 1997Powel
5649032July 1997Burt et al.
5686957November 1997Baker et al.
5729471March 1998Jain et al.
5748194May 1998Chen
5760826June 1998Nayar
5764276June 1998Martin et al.
5790181August 1998Chahl et al.
5796426August 1998Gullichsen et al.
5841589November 1998Davis et al.
5850352December 1998Moezzi et al.
5854713December 1998Kuroda et al.
5877801March 1999Martin et al.
5920337July 1999Glassman et al.
5990941November 1999Jackson et al.
6002430December 1999McCall et al.
6034716March 2000Whiting et al.
6043837March 2000Driscoll, Jr. et al.
D263716April 1982Globus et al.
D312263November 1990Charles
Foreign Patent Documents
1234341May., 1960FR
2 221 118Jan., 1990GB
2-127877Nov., 1988JP
2289820May., 1995GB
EP 0 071 492Feb., 1983FR
EP 0 637 168Feb., 1995JP
WO 94/13100Jun., 1994WO
WO 95 06303Mar., 1995WO
Other References
Charles, Jeffery R., "All-sky Reflector with "Invisible" Camera Support", Images from 1988 RTMC Proceedings, pp. 79-80. .
Roger W. Sinnott, "Scientific Library Gleanings for ATM's," Sky & Telescope, Aug. 1986, pp. 184 & 186. .
Charles et al., "How to Build and Use an All-Slu Camera," Astronomy, Apr. 1987, pp. 64-70. .
Deutsch, Claudia H., "One Camera That Offers Many Views," The New York Times. .
R. Colin Johnson, "Imaging Sytsem Sees All", Electronic Engineering Times, Dec. 25, 1996, pp. 1, 98. .
"Panospheric Camera Expands Horizon", 1 page. .
"Panospheric Camera Developed at Carnegie Mellon Expands Horizon," 1 page. .
Hamit, F., "Near-Fisheye CCD Camera Broadens View for Imaging", Advanced Imaging, Mar. 1993, pp. 50-53. .
Dixon, D., Golin, S., and Hasfield, I., "DVI Video/Graphics", Computer Graphics World, reprinted from the Jul. 1987 edition of Computer Graphics World, 4 pgs. .
Upstill, Steve, "Building Strong Images", UNIX Review, Oct. 1988, vol. 6, No. 10, pp. 63-73. .
Greene, N., "Environment Mapping and Other Applications of World Projections", Computer Graphics and Applications, Nov. 1986, IEEE Computer Society, vol. 6, No. 11, pp. 21-29. .
Heckbert, P., "The PMAT and Poly User's Manual", Computer Graphics Lab, N.Y.I.T., Feb. 18, 1983, pp. 1-29. .
Heckbert, P., "Fundamentals of Texture Mapping and Image Warping", Master's Thesis, Jun. 17, 1989, 86 pgs. .
Rebiai, M., Mansouri, S., Pinson, F., and Tichit, B., "Image Distortion From Zoom Lenses: Modeling andDigital Correction", International Broadcasting Convention, IEEE, 7/1992. .
Supplemental Information Disclosure Statement in re the Application of Steven D. Zimmermann, et al., Application No. 08/662,410, filed Jul. 12, 1996, 6 pgs. including PTO-1449 form. .
Copy of PTO-1449 form filed with the PTO on Nov. 4, 1996 in re the Application of Steven D. Zimmermann, et al., Application No. 08/662,410, jiled Jul. 12, 1996, 2 pgs. citing 19 refs. .
Defendant IPI's Notice of Reliance of Prior Art and Witnesses, Civil Action of Interactive Pictures Corporation, f/k/a Omniview, Inc. v. Infinite Pictures, Inc. and Bill Tillman, Case No. 3-96-849, filed Dec. 8, 1987, in U.S.D.C., Eastern District of Tennessee, 5 pgs. .
Defendant IPI's Composit Exhibit List, Civil Action of Interactive Pitures Corporation, f/k/a Omniview, Inc., v. Infinite Pictures, Inc. and Bill Tillman, Case No. 3-96-849, filed Jan. 5, 1998, in U.S.D.C., Eastern District of Tennessee, 20 pgs. .
Plaintiff's rule 26(a)(3) Disclosures, Civil Action of Interactive Pictures Corporation, f/k/a Omniview, Inc. v. Infinte Pictures, Inc. and Bill Tillman, Case No. 3-96-849, filed Dec. 8, 1997, in U.S.D.C., Eastern District of Tennessee, 31 pgs. .
Plaintiff's Supplemental Trial Exhibit List, Civil Action of Interactive Pictures Corporation, f/k/a Omniview, Inc. v. Infinite Pictures, Inc. and Bill Tillman, Case No. 3-96-849, filed Jan. 2, 1998, in U.S.D.C., Eastern District of Tennessee, 41 pgs. .
Ripley, G. David, "DVI-A Digital Multimedia Technology", Communications of the ACM, Jul. 1989, vol. 32, No. 7. pp. 811-820. .
Cnoe M. amd Kuno Y., "Digital Processing CF Images Taken By Fish-Eye Lens", 1982 IEEE, pp. 105-108..~
Primary Examiner: Ho; Tuan
Attorney, Agent or Firm:Curtis; Daniel B. Johansen; Dag H.
Parent Case Text


This application claims the benefit of the U.S. provisional patent application with Ser. No. 60/020,292 that was filed on Jun. 24, 1996.
Claims

We claim:
1. An apparatus for capturing panoramic images, said apparatus comprising: a convex mirror, said convex mirror reflecting light from substantially 360 degrees around said convex mirror and from a field-of-view extending through a horizon line, said convex mirror having a substantially parabolic shape; an astigmatism correction lens, said astigmatism correction lens correcting astigmatism in said light reflected from said convex mirror, said astigmatism resulting from the shape of said convex mirror; an objective lens for focusing said light reflected from said convex mirror as corrected by the astigmatism correction lens; and an image capture mechanism, said image capture mechanism capturing said light reflected from said convex mirror, whereby said light is captured linearly proportional to the incident angle of said light on said mirror.

2. An apparatus for capturing panoramic images, said apparatus comprising: a convex mirror, said convex mirror reflecting light from substantially 360 degrees around the convex mirror; at least one correction lens, the at least one correction lens correcting at least one optical aberration in said light reflected from the convex mirror, said at least one optical aberration a result of the convex mirror; and at least one image capture mechanism configured to capture a portion of said light as corrected by the at least one correction lens.

3. The apparatus of claim 2 wherein said at least one optical aberration is astigmatism and the at least one correction lens is an astigmatism correction lens configured to correct said astigmatism.

4. The apparatus of claim 2 wherein said at least one optical aberration is field curvature and the at least one correction lens is a field flattening lens configured to flatten said field curvature to a field of optimal focus.

5. The apparatus of claim 3 wherein said at least one optical aberration includes field curvature and another one of the at least one correction lens is a field flattening lens configured to flatten said field curvature to a field of optimal focus.

6. The apparatus of claim 2 wherein said light is from a band of light around the convex mirror.

7. The apparatus of claim 6 wherein said band of light around the convex mirror extends through a horizon line.

8. The apparatus of claim 6 wherein: said light reflected from the convex mirror forms an annular image; and the convex mirror is shaped such that an angle of elevation from said horizon line is linearly proportional to a radial distance of the center of said annular image.

9. The apparatus of claim 2 wherein the at least one image capture mechanism comprises photographic film.

10. The apparatus of claim 2 wherein the at least one image capture mechanism comprises an electronic image capture device.

11. The apparatus of claim 10 wherein said electronic image capture device comprises at least one charged coupled device.

12. The apparatus of claim 10 further comprising: a beam splitter, the beam splitter dividing said light into a first image and a second image; wherein the at least one image capture mechanism comprises a first electronic image capture mechanism and a second electronic image capture mechanism; and wherein said first electronic image capture mechanism captures at least half of said first image and said second electronic image capture mechanism captures at least half of said second image.

13. The apparatus of claim 2 further comprising: a protective transparent block, the protective transparent block covering the convex mirror.

14. The apparatus of claim 2 further comprising: a second mirror, the second mirror reflecting said light reflected from the convex mirror through an aperture in the convex mirror; and wherein the at least one image capture mechanism captures said light reflected from the second mirror.

15. The apparatus of claim 14 wherein the at least one image capture mechanism is housed within the convex mirror.

16. The apparatus of claim 14 further comprising: a protective transparent block, the protective transparent block covering the convex mirror.

17. The apparatus of claim 16 wherein the protective transparent block ends at said aperture in the convex mirror.

18. The apparatus of claim 16 wherein a lens system is housed within an indentation of the protective transparent block.

19. The apparatus of claim 16 wherein the protective transparent block has an external surface and said external surface is shaped such that light rays that will be reflected onto the at least one image capture mechanism enter the protective transparent block at a normal to said external surface.

20. The apparatus of claim 2 wherein said light is captured as an annular image, and said apparatus further comprises a transformation mechanism configured to transform a portion of said annular image.

21. The apparatus of claim 20 wherein the transformation mechanism comprises a computer configured to perform said transformation.

22. The apparatus of claim 20 wherein the transformation mechanism comprises circuitry configured to perform said transformation.

23. The apparatus of claims 2, 3, 4 or 5 further comprising an objective lens configured to focus said portion of said light onto the at least one image capture mechanism.

24. The apparatus of claims 2, 3, 4 or 5 wherein said portion of said light reflected from the convex mirror forms an annular image.

25. The apparatus of claims 2, 3, 4, 5, 12, 13, 14 or 19 wherein said portion of said light captured by the at least one image capture mechanism represents a capture angle of at least 45 degrees of said substantially 360 degrees of said light reflected by the convex mirror.

26. The apparatus of claim 25 wherein said capture angle is substantially 180 degrees.

27. An apparatus for capturing panoramic images, said apparatus comprising: a convex mirror, said convex mirror reflecting light from substantially 360 degrees around the convex mirror; an astigmatism correction lens, the astigmatism correction lens correcting astigmatism in said light reflected from the convex mirror, said astigmatism a result of the convex mirror; an objective lens, the objective lens focusing said light as corrected by the astigmatism correction lens onto at least one image capture mechanism; and a field flattening lens, the field flattening lens correcting field curvature in said light from the objective lens to flatten said field curvature to a field of optimal focus at said at least one image capture mechanism, said field curvature a result of the convex mirror.

28. A method for recording a panorama comprising steps of: reflecting light from a substantially 360 degree band around a convex mirror to an image plane; correcting at least one optical aberration in said light reflected from said convex mirror by at least one correction lens, said at least one optical aberration a result of said convex mirror; and capturing a portion of said light as corrected by said at least one correction lens by at least one image capture mechanism, wherein said at least one optical aberration includes astigmatism and said at least one correction lens is an astigmatism correction lens configured to correct said astigmatism.

29. The method of claim 28 wherein said at least one optical aberration includes field curvature and another one of said at least one correction lens is a field flattening lens configured to flatten said field curvature to a field of optimal focus.

30. The method of claim 28 further comprising focusing said portion of said light, corrected by said at least one correction lens, onto said image plane with an objective lens.

31. A method for recording a panorama comprising steps of: reflecting light from a substantially 360 degree band around a convex mirror to an image plane; correcting at least one optical aberration in said light reflected from said convex mirror by at least one correction lens, said at least one optical aberration a result of said convex mirror; and capturing a portion of said light as corrected by said at least one correction lens by at least one image capture mechanism, wherein said at least one optical aberration is field curvature and said at least one correction lens is a field flattening lens configured to flatten said field curvature to a field of optimal focus.

32. The method of claims 28, 29 or 31 wherein said portion of said light as corrected by said at least one correction lens represents a capture angle of at least 45 degrees of said substantially 360 degrees of said light reflected by the convex mirror.

33. The method of claim 32 wherein said capture angle is substantially 180 degrees.

34. The method of claim 32 wherein said portion of said light as corrected by said at least one correction lens forms an annular image.

35. The method as claimed in claim 34 further comprising transforming a portion of said annular image.

36. The method of claim 32 wherein said portion of said light is captured on a photographic film.

37. The method of claim 32 wherein said portion of said light is captured by at least one charged coupled device.

38. A method for capturing panoramic images comprising steps of: reflecting light from a substantially 360 degree band around a convex mirror to an image plane; correcting astigmatism in said light reflected from said convex mirror, said astigmatism a result of said convex mirror; focusing said astigmatism corrected light onto at least one image capture mechanism; and correcting field curvature in said light from the objective lens to flatten said field curvature to a field of optimal focus at said at least one image capture mechanism, said field curvature a result of the convex mirror.
Description
FIELD OF THE INVENTION

The present invention relates to the field of film and video photography. In particular the present invention discloses a camera device that captures a 360 degree panoramic image and display systems for displaying the panoramic image captured by the camera device.

BACKGROUND OF THE INVENTION

Most cameras only provide a small viewing angle. Thus, a typical conventional camera only captures an image in the direction that the camera is aimed. Limited view cameras force viewers to look only at what the camera operator chooses to focus on. Some cameras use a specialized wide angle lens to capture a wider panoramic image, but such panoramic cameras still have a limited field of view.

It would be desirable to have a camera system that would capture the light from all directions such that a full 360 degree panoramic image can be created. A full 360 degree panoramic image would allow the viewer to choose what she would like to look at. Furthermore, a full 360 degree panoramic image allows multiple viewers to simultaneously view the world from the same point, with each being able to independently choose their viewing direction and field of view.

At the present time, there are some known methods of creating 360 degree panoramic images. However, most current methods are subject to limitations due to their physical movements and mechanical complexity. For example, some of the current methods operate by combining a series of individual photographs taken in different directions into a single panoramic image. Some panoramic cameras spin a lens and film to capture a panoramic view in a single sweeping motion.

There is a market for panoramic photos to be used in multimedia applications, typically provided on CD-ROMs. In the last few years, some software manufacturers have introduced standards for digital storage and computer playback of panoramic datasets. One example is QuickTime.RTM. VR, introduced by Apple.RTM. Computer, Inc. Apple.RTM. Computer's QuickTime.RTM. VR standard governs the file storage format and the playback software needed to view their datasets.

Currently, Apple Computer recommends and provides software tools to implement a labor-intensive process for capturing these panoramic datasets. In the Apple QuickTime.RTM. VR (QTVR) process a standard 35 mm camera is mounted vertically on a leveled tripod and equipped with an extreme wide angle lens (e.g. 15-18 mm focal length). A sequence of twelve or more overlapping still photographs is taken at roughly 30 degree intervals as the camera is turned on the tripod around a vertical axis. These photographs are developed, digitized and then fed into a semi-automated software program called a "stitcher" that merges the overlapping still photographs into one long panoramic strip.

The labor intensive process suffers from a number of shortcomings. First, the process is time-consuming since many steps require human intervention and guidance. Furthermore, the recommended process is prone to temporal artifacts since it captures each individual photo at a different time. This means that the "stitched" pan image is not instantaneous but rather is made up of individual photos taken at different times. The time change during the series of photographs makes it nearly impossible to create panoramic images in changing scenes containing shorelines, urban crowds and traffic, windblown trees, etc. Finally, it is difficult to see how the image capture method recommended by Apple QuickTime.RTM. VR (QTVR) can be extended from a single still panoramic image into a continuous frame, or motion picture panoramic image capture.

SUMMARY OF THE INVENTION

The present invention discloses a camera device that instantaneously captures a 360 degree panoramic image. Furthermore, the present invention discloses various different systems for displaying the panoramic images.

In the camera device, virtually all of the light that converges on a point in space is captured. Specifically, in the camera of the present invention, light striking this point in space is captured if it comes from any direction, 360 degrees around the point and from angles 50 degrees or more above and below the horizon as illustrated in FIG. 1.

Other objects, features and advantages of present invention will be apparent from the company drawings and from the detailed description that follows below.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention will be apparent to one skilled in the art, in view of the following detailed description in which:

FIG. 1 illustrates the panoramic surroundings that are captured by the panoramic camera system of the present invention.

FIG. 2a illustrates a schematic diagram of the panoramic camera system of the present invention.

FIG. 2b illustrates a schematic diagram of the panoramic camera system of the present invention with a parabolic mirror.

FIG. 2c illustrates an annular image captured by the panoramic camera system of the FIG. 2b wherein the incident angle is linearly proportional to the radial distance of the annular image.

FIG. 3a illustrates an example of an annular image captured by the panoramic camera system of the present invention.

FIG. 3b illustrates a rectangular panoramic image after the captured annular image is transformed from polar coordinates to rectangular coordinates.

FIG. 4a illustrates photographic film used to capture the annular panoramic image.

FIG. 4b illustrates a Charged Coupled Device array used to capture the annular panoramic image.

FIG. 5 illustrates an alternate embodiment of the camera system of the present invention wherein a beam splitter is used to allow the annular image to be captured on two image planes.

FIG. 6a illustrates a first embodiment of two image planes used to capture different portions of a single annular panoramic image.

FIG. 6b illustrates a second embodiment of two image planes used to capture different portions of a single annular panoramic image.

FIG. 7 illustrates an embodiment of the panoramic camera wherein some of the optical elements are housed within the parabolic mirror.

FIG. 8a illustrates a first embodiment of the panoramic camera that uses a solid transparent block to surround the parabolic mirror.

FIG. 8b illustrates a second embodiment that uses a solid transparent block to surround the parabolic mirror which houses other optical elements.

FIG. 9a illustrates an embodiment that panoramic camera that supports the convex mirror with a central post that is out of the annular field of view.

FIG. 9b illustrates an embodiment that panoramic camera that divides the convex mirror in quarters and supports the mirror using posts between the four quarters.

FIG. 10 graphically illustrates how the annular image is sampled to product a rectangular panoramic image.

FIG. 11a graphically illustrates how an image is stored in Apple.RTM. Computer's QuickTime.RTM. VR format.

FIG. 11b graphically illustrates how viewports are created from Apple.RTM. Computer's QuickTime.RTM. VR format.

FIG. 11c illustrates a flow chart that lists how the panoramic camera system can be used to create images in Apple.RTM. Computer's QuickTime.RTM. VR format.

FIG. 12a illustrates a graphical user interface for a client program used to view panoramic still images created by the panoramic camera system.

FIG. 13a illustrates a graphical user interface for a client program used to view panoramic video created by the panoramic camera system.

FIG. 13b illustrates a networked computer arrangement used to view panoramic video created by the panoramic camera system.

FIG. 14a illustrates a side view of one embodiment of the panoramic camera system that includes microphones.

FIG. 14b illustrates a side view of one embodiment of the panoramic camera system that includes microphones.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A method and apparatus for a camera device that instantaneously captures 360 degree panoramic images is disclosed. In the following description, for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the present invention. For example, the present invention has been described with reference to Charge Coupled Devices. However, the panoramic camera system can easily be implemented with other types of electronic image capture systems.

The Basic Panoramic Camera Design

The panoramic camera design of the present invention captures light from all directions within 50 to 60 degrees above and below the horizon simultaneously. FIG. 1 graphically illustrates the cylindrical panoramic view of which the panoramic camera system captures an image. To capture all the light of the panorama and generate a two dimensional representation that may easily be recorded, the present invention uses a carefully designed and engineered collection of mirrors and lenses. The basic design of the panoramic camera of the present invention is illustrated in FIG. 2a. Each element of the panoramic camera will be described individually.

The Mirror

Referring to FIG. 2a, the panoramic camera of the present invention collects light using a convex mirror 210 that is in the approximate shape of parabolic cone. In one embodiment of the present invention, the tip of the convex mirror 210 is pointed downward as illustrated in FIG. 2a. When the convex mirror 210 is viewed from below, the parabolic mirror 210 presents an annular image of the surrounding panorama as illustrated in FIG. 3a. However, the annular image is distorted and suffers from optical defects due to the shape of the convex mirror 210.

The distortion in the image is partly due to the fact that the convex mirror 210 of the imaging system effectively converts the surrounding panorama to a polar coordinate system. By adjusting the shape of the convex mirror 210, the mapping of the elevation angle of incoming light to radial distance in the annular image, can be controlled.

In a preferred embodiment, the convex mirror 210 is a parabolic mirror that creates an annular image wherein the radial distance from the center of the annular image is linearly proportional to the angle of incident light. A panoramic camera system with a parabolic mirror is illustrated in FIG. 2b. Note that in the image plane of FIG. 2b, the distance from the center is linearly proportional to the angle of incident light. This concept is more clearly illustrated in FIG. 2c, wherein the concentric circles represent different angles of incident light.

The Astigmatism Correction Lens

The convex mirror of the present invention introduces other image defects that require careful correction. One particular problem is astigmatism. Specifically, the light reflected downward from the convex mirror 210 of the present invention will not meet at a single focal point. To correct for this problem, an astigmatism correction lens 220 is added to correctly focus the light from the convex mirror 210.

The astigmatism correction lens 220 comprises a group of 2 or more lenses whose group focal length is long but with individual elements of strong and opposite power. Thus, the astigmatism lens group may be made of the same optical material without introducing significant lateral color. Since the beam size associated with any object point in space to be imaged is quite small compared to the field of the beam, the strong elements tend to introduce deleterious amounts of spherical aberration or coma into the final image.

The Objective Lens

The next component is a standard camera objective lens 230. The standard camera objective lens 230 forms an image using the astigmatism-corrected, reflected light from the convex mirror 210. In the present embodiment, a standard off-the-shelf camera lens is used that is optimized for cost and performance in the conventional photography market. The current embodiment relies upon a pre-defined focal length.

The focal length of the standard objective lens is selected based on two factors. The first factor is the maximum angular field of view present by the convex mirror and astigmatism correction lens group. This factor is determined by the largest angle away from the horizon of an object to be captured. The second factor is the maximum diameter of the circular image to be recorded. In an embodiment that uses 35 mm film, this value would not exceed 24 mm. In an embodiment that uses Charged Coupled Device arrays, the objective lens must keep the circular image within the bounds of the CCD array.

For one preferred embodiment, the appropriate focal length is 22 mm. Since there are many objective lenses available with focal lengths in the 18 mm to 24 mm range, this focal length provides many off-the-shelf lens choices.

To allow a standard off-the-shelf camera lens to be used, the present invention "false focuses" the image beyond the normal focal plane. This allows the next optical element (field flattening lens) to fit between the objective lens 230 and the image plane 250.

The Field Flattening Lens

Another optical problem created by the parabolic mirror is a curved image field that is created by the curve of the parabolic mirror. The curved image field problem is solved by adding yet another lens 240. This final lens is a "field flattening" lens, that flattens the field of optimal focus to a flat two dimensional image plane. The field flattening lens 240 must be kept as close to the image plane as practical to eliminate the need for a focal plane shutter.

In one embodiment, the material SFL6 is used to create the field flattening lens 240. Due to its high index of refraction, SFL6 allows the field flattening lens 240 to be approximately 2 millimeters thick. If the field flattening lens 240 was created using more traditional materials, the field flattening lens 240 would be approximately 4.5 millimeters thick.

The Image Capture System

The final major component of the panoramic camera design is the image capture mechanism 250. The image capture mechanism 250 is placed at the image plane just beneath the field flattening lens 240. This mechanism captures the optimized two dimensional annular image of the surrounding panorama. An example of a captured panorama stored as a two dimensional annular representation is shown in FIG. 3a.

In one embodiment of the present invention, the image capture mechanism can be a frame of photographic film as illustrated in FIG. 4a. Using conventional photography techniques, several successive frames can be used to record series of images. The series of images may be several distinct still images taken from different locations. Alternatively, the series of images may be a set of successive images recorded used to create a panoramic motion picture. The image that is recorded onto photographic film is then later converted into a digital image for digital image processing as will be described in later sections of this document.

In the preferred embodiment of the present invention, a high resolution digital image capture system is used to capture the annular image created by the optical elements. In one embodiment of the present invention, a Charged Coupled Device (CCD) array 450 is placed in the image plane to capture the image as illustrated in FIG. 4b. Control circuitry 460 coupled to the CCD array 450 captures the image directly into a digital format. The use of a digital image capture system allows an immediate read-out of the digitized raw annular image. The digitized raw annular image can be stored into a storage device 470 such as flash memory or a hard disk drive. The CCD array 450 may be color (RGB) or black & white, depending on the intended application.

To generate an annular image of sufficient quality to be used in the Apple QuickTime.RTM. VR market, it has been determined that the image plane must be sampled with an array having at least 2K by 2K elements. To meet this requirement, one embodiment of the present invention uses a CCD array produced by Loral-Fairchild, Inc. However, the high resolution CCD array sold by Loral-Fairchild, Inc., adds a significant cost to the panoramic camera of the present invention. Furthermore, large CCD arrays such as the Loral-Fairchild array have difficulty handling the extreme differences in light intensity that are produced by the optical system of the present invention. Specifically, one area of the image may have direct sunlight and other areas may receive comparatively little light.

To reduce the production cost of the panoramic camera, alternate embodiments of the present invention use a set of lower resolution CCD arrays. Specifically, consumer grade CCD devices that are targeted at the consumer electronics market are used. Consumer electronics grade CCD arrays have the distinct advantages of lower cost, more highly-integrated support circuitry availability, high speed read-out, robustness to extreme lighting and other environmental conditions.

No individual consumer grade CCD array meets the high resolution requirements needed by the present invention (at least 2K by 2K elements). Therefore, a method of obtaining a greater image resolution is required if consumer grade CCDs are used.

One method of creating an acceptable image capture mechanism using consumer grade CCD arrays is to use multiple low resolution CCD chips to cover the image plane using a mosaic pattern. Referring to FIG. 5, the basic panoramic camera configuration described in the previous sections is illustrated except the last stage has an added beam-splitter 545 that directs a second image to a second field flattening lens 541 and a second image plane 551. The beam-splitter 545 may comprise a half-silvered mirror or a prism arrangement as is known in the art. The two image planes (image plane 551 and image plane 553) each capture a portion of the whole annular image. To construct a complete image, the camera optically composites the images from the two different image planes into a single image.

FIGS. 6a and 6b each illustrate one possible embodiment of the dual image plane image capture system. FIG. 6a illustrates a mosaic pattern created with four consumer grade CCD devices. As illustrated in FIG. 6a, the two image planes capture the whole annular image while each image plane leaves room for the chip lead frames and support circuitry. FIG. 6b illustrates an alternate embodiment that six consumer grade CCD devices. An additional advantage of this scheme is that the CCD array chips can potentially share some supporting circuitry since the signals each independent chip requires are often identical.

A disadvantage of the mosaic technique is the image capture variation that will exist between the different CCD chips. The image variation can be compensated for by having overlapping CCD array coverage. The overlapping area is used to cross calibrate the image variation between adjacent CCD arrays.

Folded Optics Configuration

FIG. 7 illustrates an alternative embodiment of the panoramic camera system. In the embodiment of FIG. 7, the camera subassembly is housed within the parabolic mirror. Referring to FIG. 7, the convex mirror 710 is inverted and a hole is cut into the tip. A second mirror 715 is placed above the convex mirror 710, directing the light from the surrounding panorama into the hole in the top of the convex mirror 710. The remainder of the optical path, including the astigmatism correction lens
720, the objective lens 730, the field flattening lens 740, and the image capture mechanism 750, are all housed inside the inverted convex mirror 710. It is apparent from the diagram of FIG. 7 that the "folded optics" configuration protects the optical path and mechanical parts of the panoramic camera system.

Transparent Block Configuration

Another alternative embodiment is shown in FIG. 8a. In this alternative, the convex mirror is formed as the internal space of a curved block of transparent material such as glass or plastic. The mirror surface 810 is formed by the inner surface of a hole that is milled or cast in the top of the transparent material 805. The shape of the outer surface approximates a sphere centered on the virtual focal point of the convex mirror 810. The outer surface of the transparent material is a polished surface that forms the outside skin of the camera. The bottom tip of the transparent block is optically mated to the other optical parts of the camera system. The bottom tip may be polished flat or molded into a shape that contributes to the astigmatism lens group.

The solid transparent block approach has a number of significant advantages. First, the mirrored inner surface of the transparent block material can be well protected. This technique overcomes the disadvantages of front surface mirrors. Specifically, when front surface mirrors are exposed to the outside world they are susceptible to damage and degradation. In the above described embodiment, the mirrored surface is fully protected since it is encased between a protective backing material and the transparent block material. Another advantage of the solid block approach is that the skin of the camera is incorporated into the optical system. Thus only one surface would need to be multicoated to prevent internal reflections.

The transparent block technique can also be implemented using the folded optics scheme described in the previous section. Specifically, FIG. 8b illustrates an inverted solid transparent block used to implement a panoramic camera system. In this case, the camera components are contained within the mirror cavity. Note that the outside surface at the top of the block is no longer an exit path but is instead a mirrored surface that directs the image light down into an optical path inside the parabolic block.

Different methods can be used to construct a transparent block panoramic camera system. One method would be to create the transparent block, then polish the transparent block, and finally add a mirrored surface where appropriate. An alternate method of constructing a transparent block panoramic camera system would start with the convex mirror. Then, the convex mirror would be encapsulated within the transparent block. This method would be simpler to construct since a concave surface would not require polishing. Furthermore, the convex mirror would be protected by the transparent block.

Center Support Configuration

Another alternative embodiment addresses the problem of how to align and support the optical elements of the panoramic camera illustrated in FIG. 2a. It is possible to use the protective, transparent block technique as described in the previous section to provide structure, stability and alignment. However, the transparent block technique requires multicoating of the surfaces or else undesired internal reflections will be visible. FIG. 9a discloses an alternate embodiment wherein a central post 903 is used to support the parabolic mirror 910. The remainder of the optical system is below the parabolic mirror 910 and the central post 903. The center support scheme takes advantage of the fact that the center of the annular image is discarded since it contains only an image of the camera itself. Therefore, the center portion of the annular image can be used for support of the parabolic mirror 910.

External Support Configuration

Another scheme for supporting the parabolic mirror above the optical elements below is to use several side supports. This can be accomplished by splitting the parabolic mirror into "pie-pieces" by cutting the parabolic mirror after fabrication. For example, the parabolic mirror can be quartered as illustrated in FIG. 9b. The four sections of parabolic mirror 1021, 1022, 1023, and 1024 can be spread apart slightly, allowing for the introduction of supporting elements 1031, 1032, 1033, and 1034
that will not obstruct the fields of view.

If the parabolic mirror is split into four sections, then the annular image will appear as four quadrants at the image plane. To correct for this, the gaps can be removed during the polar-to-rectangular coordinate conversion, thereby restoring the continuity of the panoramic image. The gaps between the mirror sections should be kept as small as possible, however, since the optical system is degraded by the loss of rotational symmetry.

Panoramic Image Presentation

As illustrated in FIG. 3a, the panoramic camera system of the present invention records a two dimensional annular representation of the surrounding panorama. However, the annular representation is not of much interest to most viewers. Therefore, to display the panoramic images captured by the panoramic camera of the present invention, several different display systems are disclosed.

Still image presentation as a rectangular panoramic image

The most common method of displaying a panoramic image is to display the image as a rectangle where the horizontal direction represents the view angle. An example of this type of panoramic image presentation is illustrated in FIG. 3b. Such rectangular panoramic images are commonly displayed in nature magazines. As stated in the background, the prior art method of creating such rectangular panoramic images was to take several conventional photographs at different angles and then stitch those photographs together somehow.

With the panoramic camera system of the present invention, such rectangular panoramic images can easily be created. First, the panoramic camera system of the present invention is used to capture an annular image of the surrounding panorama. Then the annular image is digitized and loaded into a computer system. (The image will already be in digital form if a CCD version of the panoramic camera system was used to capture the image.)

A custom conversion program is then executed on the computer system. The custom conversion program scans around the annular image starting at an arbitrarily chosen sampling line 310. Points along the sampling line 310 are sampled and then their position changed using polar coordinate to rectangular coordinate conversion. FIG. 10 illustrates how two different points on the annular image are sampled and then placed into rectangular coordinates. As illustrated in FIG. 10, the orientation of the sampling pattern changes as the coordinate transform program rotates around the annular image. The resulting rectangular image is illustrated in FIG. 3b.

While sampling the annular image, it is important to sample the image differently depending on where the annular image is being sampled. The following three rules must be observed: 1. The sampling shape is dynamically changing depending on the viewing angle (both in the horizontal and vertical).

2. The sampling shape size is proportional to the radius (vertical viewing angle); and 3. The sampling shape orientation is different depending on the horizontal viewing angle.

Since there is a greater resolution around the outer perimeter of the annular image, the corresponding rectangular image portion will have better image clarity. The outer perimeter of the annular image may be the top or the bottom of the rectangular image depending on the optical path. (Compare FIG. 2a with FIG. 7). In FIG. 10, the lower portion of the rectangular image will have a better image clarity since it is from the outer perimeter of the annular image. One embodiment of the present invention takes advantage of this fact by using the outer perimeter of the annular image for the ground since the ground in a panoramic scene is generally more detailed than the sky.

Once the panoramic image has been converted from an annular image to a rectangular image on a computer system, then the rectangular image can be presented to viewers in a number of different formats. For example, the rectangular image may be distributed electronically as a JPEG image and viewed with JPEG image viewers. Alternatively, the rectangular image can be printed out with a color printer. It should be noted that since the rectangular image is in digital form, it can quickly be added to a publication being created with a Desktop Publishing Layout Program such QuarkXpress or Adobe's PageMaker.

Image presentation as a Virtual Reality image

Apple Computer introduced a standard known as QuickTime.RTM. VR for storing and displaying virtual reality images. Apple Computer's QuickTime.RTM. VR standard governs the data storage format and the playback software needed to view the QuickTime.RTM. VR datasets. The camera system of the present invention can be used to quickly create QuickTime.RTM. VR datasets.

The QuickTime.RTM. VR format stores the image as cylindrical image as illustrated in FIG. 11a. Specifically, the viewpoint is at the center of the cylinder and the inner surface of the cylinder represents the stored QuickTime.RTM. VR image. Note that trapezoid shaped patches must be sampled to generate an image if the user is looking up or down as illustrated in FIG. 11b.

FIG. 11c illustrates a flow diagram that lists the steps required to produce a QuickTime.RTM. VR dataset using the panoramic camera system of the present invention. First, at step 1110, a panoramic image is recorded with the panoramic camera. Then, at step 1120, the recorded image is digitized and loaded into a computer system. If the panoramic camera recorded the image on a piece of film, then a print of the film can be scanned into the computer system using a flatbed scanner. Alternatively, a film image can be commercially transformed into the well known PhotoCD.RTM. format produced by Kodak.RTM.. If the panoramic camera recorded the image with a CCD array and stored the image digitally, then the digital image is just copied from the camera's storage system into the computer system's storage system.

After the digital version of the annular image is available on the computer system, a transformation program is then executed on the computer system at step 1130 in order to transform the digitized annular image into a QuickTime.RTM. VR dataset. The annular image produced by the camera system of the present invention stores the panoramic image information in a polar coordinate system. Conversely, Apple.RTM.'s QuickTime.RTM. VR uses a cylindrical coordinate system as illustrated in FIG. 11a. Thus, the transformation program converts the annular image from its polar coordinate system into the QuickTime.RTM. VR cylindrical coordinate system. After transforming the image into the QuickTime.RTM. VR cylindrical coordinate system, then a file is created using the QuickTime.RTM. VR file format at step 1135.

Once the coordinate transform is complete, the transformed image can be viewed using Apple's QTVR player program as stated in step 1140.

Still image presentation on a computer network

Since the present invention can store the annular image in digital form, a very useful method of distributing panoramic images is through a computer network. In particular, the hypertext transport protocol (http) of the World Wide Web (WWW) on the Internet can be used to distribute still annular images. The still annular images would be stored on a World Wide Web server. To access the still annular images, any user coupled to the Internet would use a World Wide Web browser program.

One method of transporting the images would be to define a new panoramic image annular data format. The images could then be downloaded as stored in the panoramic image annular data format. A helper application would then display the images once downloaded.

A better method of displaying images using the hypertext transport protocol (http) of the World Wide Web (WWW) would be to implement a "plug-in" application that would work with the browser program. FIG. 12a illustrates a graphical user interface for one possible client panoramic image presentations system. On the right side of FIG. 12a, a set of different panoramic images to display is available. To display one of those images, the user selects the image with a cursor control device. On the upper left of the graphical user interface of FIG. 12a is viewport for displaying a portion of a panoramic image. Pan arrows on either side of the viewport allow the user to pan left and right.

Image Presentation As Video

One of the most interesting presentation systems for the present invention is a video presentation system. FIGS. 13a and 13b illustrate one possible video presentation system.

Referring to FIG. 13a, a CCD version of the panoramic camera system 1205 of the present invention is illustrated coupled to a computer system 1200. The CCD version of the panoramic camera system 1205 is coupled through a panoramic camera interface 1210. The panoramic camera interface 1210 receives a digital stream of annular images. To interface with computer systems, one embodiment of the panoramic camera interface 1210 is the FireWire system that is described in the IEEE 1394
standard.

After being received through the panoramic camera interface 1210, the digitized annular images are stored in an Annular "Video" Storage system 1230. The Annular "Video" comprises a series of a consecutive annular images taken with a CCD version of the panoramic camera system 1205.

To display the Annular Video as normal video, the annular frames must be converted from the annular image format into normal video images. In one embodiment of the present invention, only a portion of the annular image is converted into normal video. One reason for this is that the aspect ratio of video does not allow for good viewing of wide but short rectangular panoramic images. Furthermore, by only transforming a portion of the annular image into normal video, the transformation can be done in real-time without requiring exceedingly fast computer equipment. The transformation of annular video to normal video is done by annular to video conversion units 1240 and 1243.

To display the normal video, existing video streaming software 1260 and 1263 can be used. For example, using a standard transmission protocol like MPEG or proprietary protocols such as StreamWorks produced by Xing Technology Corporation of Arroyo Grande, Calif., or VDOLive produced by VDOnet Corporation of Santa Clara, Calif., the video can be provided to computer users coupled to a network.

FIG. 13b illustrates one possible embodiment of a graphical user interface (GUI) for accessing the annular video. In the GUI of FIG. 13b, a video viewport 1340 is used to display the video. A smaller still panoramic image 1310 is used to illustrate a static version of the full panoramic video. A locator window 1315 is used to identify the view angle that the video window 1340 is displaying within the full panoramic view that is available.

To change the view angle, the user can select a pan right arrow 1347 or a pan left arrow 1343 with a cursor 1320. Alternatively, the user can simply move the position of the locator window 1315 within the still panoramic image 1310. In the embodiment of FIG. 13b, the entire vertical image aspect of the image is compressed into the video viewport 1340.

Referring back to FIG. 13a, user input processing routines 1250 and 1253 processing the user's commands. When the user requests a viewpoint change, the new viewpoint is communicated to the respective annular to video conversion units 1240 or
1243 such that it will begin converting images from the new user viewpoint. In an alternate embodiment, the user input processing routines are placed within the client program on the client computer system. For example, in an embodiment of a WWW browser program, a plug-in program can process the user commands and simply pass the location of the video viewport to the server.

Referring back to FIG. 13b, a parameter window 1350 is also available to the viewer. The parameter window 1350 allows the user to adjust some of the viewing parameters such as Image Brightness 1352, Image Tint 1353 and Image Contrast 1355. When a user adjusts these parameters, the changes will be processed by the user input processing routines 1250 and 1253 provided to the annular to video conversion units 1240 or 1243 or the video streaming software 1260 or 1263 such that video quality is changed.

Telepresence: Video and Audio

To more completely convey the experience of being at a different location, the present invention can be combined with a three dimensional sound system. Referring to FIGS. 14a and 14b, an embodiment of the camera system is illustrated with four directional microphones 1441, 1442, 1443, and 1444. The four directional microphones 1441, 1442, 1443, and 1444 capture sound emanating from four cardinal directions.

To add three dimensional sound, the sound from the various directional microphones is mixed depending on the viewing angle that a user has selected. For example, if a viewer that is seeing a real-time image from camera 1400 of FIG. 14a is viewing straight out of the page, then the left speaker will receive information from microphone 1443 and the right speaker will receive information from microphone 1441. The sound can be provided to users on a computer network using audio streaming software such as RealAudio by Progressive Networks, Inc. As the viewer adjusts the viewing angle, the sound from the directional microphones will be adjusted accordingly.

By adding sound to the system, the user is provided with cues as to which direction they should be viewing. For example, if the user hears a sound from "behind", then the user can change the view angle to look backward.

The foregoing has described a camera device that captures 360 degree panoramic images and presentation systems for displaying such images. It is contemplated that changes and modifications may be made by one of ordinary skill in the art, to the materials and arrangements of elements of the present invention without departing from the scope of the invention.

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