WO1998025179A2

WO1998025179A2 - Optical projection systems and methods having an image relay adapter

Info

Publication number: WO1998025179A2
Application number: PCT/US1997/022011
Authority: WO
Inventors: D'nardo Colucci
Original assignee: Alternate Realities Corporation
Priority date: 1996-12-03
Filing date: 1997-12-03
Publication date: 1998-06-11
Also published as: AU5791298A; WO1998025179A3

Abstract

An optical projection system includes an image forming system such as projector including an image source and an image relay adapter. The image source includes an array of image pixels. The image relay adapter includes a body having an inlet operatively connected with the image source and an outlet separated by a predetermined distance from the inlet. The image relay adapter also includes an image relay system in the body which receives the image from the image forming system and relays a replica image to the outlet. A hemispherical projection system can be operatively connected with the outlet of the image relay which projects the array of image pixels from the image relay adapter onto a truncated spherical surface at a projection angle of at least 160 degrees. Further, the hemispherical optical projection system can project the array of image pixels into a hemispherical projection having constant angular separation among adjacent image pixels, such that the projection is suitable for projection onto truncated spherical surfaces of varying radii without requiring spatial distortion correction of said array of image pixels. An acquisition device can also be utilized with the image relay adapter of the optical projection system to acquire images suitable for hemispherical projection at an angle of projection of at least 160 degrees without spatial distortion. Methods of hemispherical optical projection are also provided.

Description

OPTICAL PROJECTION SYSTEMS AND METHODS HAVING AN IMAGE RELAY ADAPTER

Field of the Invention

This invention relates to optical projection systems and methods, and more particularly to hemispherical optical projection systems and methods.

Background of the Invention

Hemispherical optical projection systems and methods, i.e. systems and methods which project images at an angle of at least about 160 degrees, are used to project images onto the inner surfaces of domes. Hemispherical optical projection systems and methods have long been used in planetariums, commercial and military flight simulators and hemispherical theaters such as O IMAX^® theaters . With the present interest in virtual reality, hemispherical optical projection systems and methods have been investigated for projecting images which simulate a real environment. Such images are typically computer-generated multimedia images including video, but they may also be generated using film or other media. Home theater has also generated much interest, and hemispherical optical projection systems and methods are also being investigated for home theater applications.

Hemispherical optical projection systems and methods have generally been designed for projecting in a large dome having a predetermined radius . The orientation of the hemispherical projection has also generally been fixed. For example, planetarium projections typically project vertically upward, while flight simulators and hemispherical theaters typically project at an oblique angle from vertical, based upon the audience seating configuration. Hemispherical optical projection systems and methods have also generally required elaborate color correction and spatial correction of the image to be projected, so as to be able to project a high quality image over a hemisphere. Virtual reality, home theater and other low cost applications generally require flexible hemispherical optical projection systems and methods which can project images onto different size domes and for different audience configurations. The optical projection systems and methods should also project with low optical distortion over a wide field of view, preferably at least about 160 degrees. Minimal color correction and spatial correction of the image to be projected should be required. In copending United States Patent Application

Serial No. 08/593,699 to Colucci et al . , filed January 29, 1996, entitled "Til table Hemispherical Optical Projection Systems and Methods Having Constant Angular Separation of Projected Pixels " (hereinafter "Application Serial No. 08/593,699") and assigned to the assignee of the present application, tiltable, hemispherical optical projection systems and methods are illustrated which project an array of image pixels formed by an image source into a hemispherical projection having constant angular separation among adjacent pixels onto a truncated spherical or hemispherical surface. Projection is preferably from the center of curvature of the inner surface of a dome. The hemispherical optical projection systems and methods also project the array of image pixels onto a hemispherical surface at a projection angle of at least 160 degrees and project onto hemispherical surfaces of varying radii without requiring spatial distortion correction of the image to be projected.

Summary of the Invention

Optical projection systems and methods having an image relay adapter are ^'provided according to the present invention. The optical projection systems include an image forming system and an image relaying adapter operatively connected with the image forming system. In one embodiment, the image forming system forms an image, preferably, for hemispherical projection on a hemispherical inner surface of a dome. The image relay adapter relays the image formed by the image forming system and received in an inlet of the image relay to a replica image at an outlet of the image relay. The image is then projected by a hemispherical optical projection system in a hemispherical projection on the curved surface of a dome.

In another embodiment, the optical projection system preferably includes a dome having a truncated spherical inner surface and an image forming system, such as a projector, including an image source having an array of image pixels. The array of image pixels is formed and transmitted to the image relay adapter, preferably embodied as an elongated light pipe . The image relay adapter is operatively connected with the image source of the image forming system. The projector, including the image source, is preferably offset and positioned a predetermined distance from the center of curvature of the dome, and is preferably positioned so as to not obstruct the line of sight of the viewing audience in the dome .

The image relay adapter relays the image formed by the projector and received in an inlet of the image relay adapter to a replica image near an outlet of the image relay adapter. The image relay adapter is preferably lightweight, easy to assemble, and has a narrow width to further reduce sight obstruction for viewers in the dome .

The replica image is then projected onto a truncated spherical surface of the dome, preferably by a lens assembly having an exit pupil located near the center of curvature of the dome. The lens assembly is operatively connected with the image relay adapter. The lens assembly can project the replica image of the array of image pixels in a hemispherical projection on a truncated spherical inner surface of the dome at an angle of projection of at least about 160° without requiring correction for spatial distortion. The optical projection system also can project an array of image pixels into a hemispherical projection having constant angular separation between adjacent image pixels such that the optical projection system projects the array of image pixels onto hemispherical or truncated spherical surfaces of varying radii without requiring spatial distortion correction of the array of image pixels.

The optical projection system having the image relay adapter preferably has a modular multi- piece portable dome assembly which can be assembled, disassembled and moved from location to location. As such, the lens assembly and image source also, preferably, are easily releasably connected with and disconnected from the image relay adapter.

In another embodiment of the optical projection systems having an image relay adapter according to the present invention, a lens assembly or other wide angle element is operatively connected with an image relay adapter. The image relay adapter is also preferably operatively connected with an image acquisition device such as a film or digital camera.

In one embodiment, the lens assembly focuses light into the inlet of the image relay adapter. The inlet of the image relay adapter is located in the diverging beam after the focus of the wide angle element. The image relay adapter relays the focused light image from the lens assembly through the inlet to an outlet of the image relay adapter such that a replica image is received in the image acquisition device. The image acquisition device receives the image in a form suitable for later hemispherical projection on a truncated spherical, and preferably a hemispherical, surface at a projection angle of at least about 160° without requiring correction for spatial distortion. In another embodiment, the inlet of the image relay adapter can be located in the convergence beam before the focus of the wide angle element. In either embodiment, the image relay adapter is easily connected and disconnected with the lens assembly and the digital or film camera. Such a system can be utilized to acquire images which later can be projected on the truncated spherical surface of a dome by the optical projection system described previously herein.

Methods of optical projection utilizing an image relay also are provided according to the present invention. An image is formed at an image forming location offset a predetermined distance from the center of curvature of a dome. The image is formed including an array of image pixels suitable for radial projection onto a truncated spherical, and preferably, a hemispherical surface. The image is then relayed from the image forming location such that a replica image is received in the image relay location. The replica image is then projected from an image projecting location onto the truncated spherical inner surface of the dome for viewing. The array of image pixels is preferably projected onto the truncated spherical inner surface of the dome at a projection angle of at least about 160 degrees. The image is, likewise, preferably projected onto the inner surface of the dome in a hemispherical projection having constant angular separation between adjacent pixels of the array of image pixels. The array of image pixels is projected such that the hemispherical projection can be projected onto domes of varying radii without the need for correction for spatial distortion.

The optical projection systems and methods having an image relay adapter facilitate viewing of centrally projected hemispherical projections in a dome. Further, the light weight and ease of assembly enhance the ease of use of the optical projection system according to the present invention.

Brief Description of the Drawings

Figure 1 is a diagram of a hemispherical optical projection system and method having an image relay adapter according to the present invention.

Figure 2 is a perspective view of the optical projection system of Figure 1.

Figure 3 is a partially exploded, cutaway view of the optical projection system of Figure 2.

Figure 4 is detailed view of the image relay adapter of Figure 3. Figure 5 is a diagram of an alternative embodiment of the optical projection systems including a lens assembly, the image relay adapter and a single lens reflex camera.

Figure 6 is a diagram of a further alternative embodiment of the optical projection systems including a lens assembly, the image relay adapter and a motion picture film camera.

Detailed Description of Preferred Embodiments

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like e1ements throughout . Referring now to Figure 1, an optical projection system having an image relay adapter according to the present invention is illustrated. The optical projection system 10 includes a dome 15, an image forming system illustrated as a projector 20, an image relay adapter 30 illustrated as an elongated light pipe and a lens assembly 25. The projector 20 is preferably positioned a predetermined distance from the center of curvature 17 of the inner surface 16 of the dome 15 and out of the line of view of viewers in the audience viewing area 22 within the dome 15. The image relay adapter 30 is releasably and operatively connected with the projector 20 to receive and relay an image having an array of image pixels produced by the projector 20. The image relay adapter 30 is also releasably and operatively connected with the lens assembly 25 to relay the image from the projector 20 to the lens assembly 25 for hemispherical projection 12 on the truncated spherical inner surface 16 of the dome 15. The lens assembly 25 has an exit pupil preferably positioned near, and more preferably positioned at, the center of curvature 17 of the inner surface 16 of the dome 15.

In the domed environment illustrated in Figure 1, the optical projection system 10 preferably projects an image into a hemispherical projection 12 having constant angular separation among adjacent pixels as indicated by angle θ which is constant among adjacent pixels 12a-12n. For example, a circular array of 768 pixels may be projected at a constant angular separation of 13.7 arcminutes at 175 ° full field of view. The optical projection system 10 projects the hemispherical projection having constant angular separation onto the inner surface 16 of the truncated spherical inner surface of the dome 15. Such projection is further discussed in the previously referenced Application Serial No. 08/593,699. The optical projection system having a constant angular separation may be regarded as an "inverse telephoto" system having an f^• θ lens. The image height is proportional to f - θ , where f is the focal length of the lens and θ is the constant angular separation among adjacent pixels.

By maintaining constant angular separation among adjacent pixels, a low distortion image can be projected by the optical projection system 10 onto domes of varying radii, shown by 15' . For example, domes of radii from 4 to 8 meters may be accommodated. In order to maintain low distortion with constant angle of separation, the lens assembly 25 of the optical projection system 10 is preferably mounted with its exit pupil located near, and more preferably at the center of curvature 17 of the inner dome surface 16 so as to radially project the array of pixels onto the inner dome surface 16. The lens assembly 25 is also preferably positioned with its exit pupil near, and more preferably, at the center of curvature 17 of the dome 15 to project an optical projection on the inner surface 16 of the dome 15 at a projection angle of at least 160 degrees without requiring correction for spatial distortion. Examples of such projections also can be seen in Application Serial No. 08/593,699 previously referenced herein.

As also illustrated in Figure 1, the image relay adapter 30 is connected with the lens assembly 25 having its exit pupil positioned at the center of curvature 17 of the inner surface 16 of the dome 15 to allow the projector 20 to be positioned a sufficient distance away from the center of the dome 15 so as to eliminate sight obstruction for viewers positioned in an audience viewing area 22.

The dome 15 is preferably constructed for portability and ease of assembly and disassembly. A preferred construction for the dome 15 is described in copending application Serial No. 08/593,041 to Zobel et. al filed January 29, 1996 entitled "Mul ti -Pieced, Portable Projection Dome and Method of Assembling the Same " (Hereinafter "Application Serial No. 08/593,041") and assigned to the assignee of the present application, the disclosure of which is hereby incorporated herein by reference.

Referring to Figures 1 and 2, the projector 20 includes an image source having array of image pixels which are preferably projected as a combined or single path 24. An example of such a projector 20 and image source is illustrated in Application Serial No. 08/593,699 previously referenced herein. Various projectors can be utilized including the Ampro Model No. 7200, film projectors including the Pioneer ^® linear loop 35 mm projector and the like, projectors incorporating micro mirror display such as those built by Texas Instruments, and digital projectors such as LCD projectors and light valve projectors, and the like. In the projector 20 described in Application

Serial No. 08/593,699, the image source project arrays of image pixels onto respective liquid crystal layers (not shown) . The array of pixels from the image, as illustrated, includes a predetermined height and predetermined width. The optics of the image projector 20 produces a combined light path 24. The combined light path 24 is transmitted from the projector 20 into a hole 29 in the inlet 33 of the image relay adapter 30.

Image sources may be a cathode ray tube, a field emitter array or other two dimensional image array. Other light paths and types of images can be projected from the projector 20 or other image forming systems for use in the optical projection systems and methods having an image relay adapter according to the present invention. The inlet 33 of the image relay adapter 30 is operatively connected with the projector 20. A collar 55 surrounds the lower portion of the image relay adapter 30 to stabilize the connection of the projector 20 and the image relay adapter 30. Referring to Figures 2 to 4 , the image relay adapter has an elongated body 32 which is illustrated as a five foot aluminum tube. The body 32 is formed by joining a plurality of hollow, cylindrical tubes 36, 39, 40, 41 and 42 and an elbow 46. Each of the tubes 36, 39, 40, 41 and 42 and elbow 46 have an inlet end and outlet end. The cylindrical tubes 36, 39, 40, 41 and 42 and elbow 46 are connected by placing the adjacent inlet end 67 of a tube 39 into the outlet end 66 of an adjacent tube 36 and connecting the tubes 36 and 39. in a press fit connection. The outlet end 66 of tube 36 has a larger diameter than the adjacent inlet end 67 of tube 39 to facilitate joining of the tubes and transmission of images through the hollow interior of the body 32 (Figure 4) . The series of tubes 36, 39, 40, 41 and 42 and elbow 46 are similarly joined in press fitting joints 57, 58, 59, 60 and 61 to form the elongate body 32 of the image relay adapter (Figure 3) . The tubes 36, 39, 40, 41 and 42 and elbow 46 can be joined with other connectors and fasteners including mating threaded ends, press-fit connectors, snap-fit connectors and fasteners such as screws, bolts, clamps, and collars. Additionally, the tubes and elbow can be connected with various bonding agents such as adhesives and resins.

Further, other configurations and combinations of tubes and elbows can be employed in forming the body of the image relay adapter. Image relay adapters in other forms, can be provided having various straight and curved configurations. A body can be provided with or without an elbow or elbows depending of the location of the projector and desired projection angle. For example, an image relay adapter may be formed having a straight body which can be employed for use with the hemispherical projection system in a vertical planetarium projection with a projector offset from the center of curvature of the dome, but located directly below the lens assembly or other projection system located at the center of curvature of the dome .

The tubes 36, 39, 40, 41, 42 and elbow 46 are lightweight, easily constructed and formed of aluminum, a material having desired mechanical properties for mounting or holding lenses and other apparatus of an image relay system which relay images or, alternatively, transmit light, within the interior thereof. Preferably, the interior surface of the elongate body 32 is coated with a non-reflective black material. Suitable other materials which can be employed including various polymer materials.

The elongated body 32 extends longitudinally from the projector 20 at a predetermined angle α. The first tube 36 of the body 32 is releasably connected with the projector 20 in a projection opening of the projector 20. The collar 55 surrounding the first tube 36 retains the tube 36 and body 32 in its desired angle of orientation a . The image relay adapter 30 includes an arm 50 connected between the body 32 and projector 20 which supports the image relay adapter 30 at a predetermined angle of projection with respect to the dome 15. The arm 50 can be provided as a pivot, sling support, brace or other support mechanisms which can support the body 32 at a variety of predetermined projection angles with respect to the dome 15. The image relay adapter 30 also can be formed in other configurations and with other support mechanisms which position the image relay adapter to facilitate projection onto the inner surface of the dome at predetermined, selected angles of projection. Other configurations of the image relay adapter can be provided including various lengths, shapes, sizes and materials depending of the desired type and length of image transmission. Also, a body for an image relay adapter may be formed of a single piece of material.

An image relay system 35 is positioned in the body 32 of the image relay adapter 30. The image relay system 35 includes a series of optics including an image plane 38, lenses 37, 43 and 44 and mirrors 47 for relaying the image including the array of pixels received from the projector 20 from the inlet 33 to the outlet 34. The specifics of the optics of the image relay system 35 are illustrated in Figures 2 and 3.

The image relay system 35 receives the image in the form of an array of pixels projected from the projector 20. Lenses 37, 43, 44 and a mirror 47 are positioned between the inlet 33 and the outlet 34 in the path of travel of the image. The array of image pixels is transferred through the lens 37, 43, 44 and deflected by mirror 47 such a replica image is relayed from the inlet 33 to the image plane 38 positioned adjacent to the outlet 34 of the image relay adapter 30.

The mirror 47 is positioned in the elbow 46 to reflect the array of image pixels to the outlet to facilitate angled projection from near the center of curvature 17 of the inner surface 16 of the dome 15. The image plane 38 receives the replica image from the projector 20 at the inlet 33 of the image relay adapter 30. Alternatively, the image relay adapter 30 can receive the replica image at various locations therein. Further, alternatively, the light can pass through the image relay adapter without being focused in an image therein as described herein.

The body 32 also includes a connecting ridge 53 configured to receive and threadingly engage the lens assembly 25 (Figure 3) . The ridge 53 includes threads 54 which threadingly engage mating threads in the lens assembly 25 and maintain the lens assembly 25 in a predetermined projection orientation with relation to the inner surface 16 of the dome 15. Preferably, the lens assembly 25 is releasably connected with the image relay adapter 30 to facilitate assembly and disassembly of the hemispheric optical projection system 10. Other connectors can be utilized to support and connect the lens assembly 25 with the image relay adapter 30. Such connectors are known to one of ordinary skill in the art and are therefore not discussed in detail herein.

The image relay adapter 30 is lightweight, easily assembled and shipped, and thereby facilitates use with a portable, multi-piece dome 15 as described in Application Serial No. 08/593,041, previously discussed herein. The slender, elongate body 32 of the image relay adapter 30 facilitates the use of the optical projection system in a dome 15 by removing the projector 20 from sight lines of viewers in the audience viewing area 22 in the dome 15. The projector 20 is preferably positioned on the floor of the dome 15, and thereby is eliminated from sight. Alternate configurations and sizes of the image relay adapter can be provided which allow placement of the projector 20 at various positions within or outside the dome 15. An example of the lens assembly 25 utilized with the optical projection system 10 can be seen in Application Serial No. 08/593,699, particularly in Figure 2 of that application and related description, which are also incorporated by reference. Other optical projection systems can be utilized with the image relay adapter according to the present invention. Such optical projection systems are also preferably positioned with the exit pupil near, and more preferably at, the center of curvature of the inner surface of the dome with the image relay adapter used to remove bulky or unsightly elements from the sight of view.

The lens assembly 25 is operatively connected with the outlet 34 of the image relay adapter 30. The lens assembly is positioned at the center of curvature 17 of the inner surface 16 of the dome 15. The exit pupil of the lens assembly is positioned at the center of curvature 17 of the inner surface 16 of the dome 15. The lens assembly 25 receives the replica image of the array of image pixels from the image relay adapter 30 and projects the array of image pixels in a hemispherical projection on a truncated spherical inner surface 16 of the dome 15 at an angle of at least about 160° without requiring correction for spatial distortion. The lens assembly 25 also projects an array of image pixels into a hemispherical projection having constant angular separation between adjacent image pixels such that the optical projection system projects the array of image pixels onto hemispherical surfaces of varying radii without requiring spatial distortion correction of the array of image pixels.

The optical projection system 10, alternatively, may include means for tilting the hemispherical projection having a constant angular separation among adjacent pixels, so that the constant angular separation hemispherical projecting system shown as the lens assembly 25 projects the array of pixels onto a plurality of selectable positions on the inner surface 16 of the dome 15. The lens assembly 25 may be tiltably mounted to allow tilting within a plane or in multiple planes. For example, alternatively, a tilting mechanism which adjusts the angle of projection of the lens assembly 25 in relation to the inner surface 16 of the dome 15 and the image relay adapter 30 can be provided to enable projection at varying angles on the hemispherical inner surface of a dome.

For example, a servo-motor controlled pivot device can be connected with the image relay adapter for adjusting the projection angle of the lens assembly.

By incorporating a tilting mechanism with the lens assembly 25, the optical projection system 10 can project vertically upward in a planetarium projection or may project at an angle (for example 45 degrees) from vertical in a theater projection position. Typically, when projecting in a planetarium style, the audience area surrounds the projection system 10. In contrast, when projecting theater style, the audience area 22 is typically behind the optical projection system 10 and the audience area 22 is raised so the audience can see the entire field of view in front of them.. Thus, different audience configurations are accommodated.

Referring now to Figure 5, an alternative embodiment of an optical projection system 100 including an image relay adapter 105, the lens assembly 25 previously described, and a film camera illustrated as a single lens reflex 35 mm still picture camera 102 is illustrated. Single lens reflex cameras are known to one of ordinary skill in the art and are not therefore described in detail herein. The image relay adapter 105 is releasably connected between the camera 102 and the lens assembly 25. The image relay adapter 105 includes a body 106 having an inlet 108 and an outlet 110 separated from the outlet 110 by a predetermined distance. The body 106 of the image relay adapter 105 also includes a hollow cylindrical aluminum tube 107. Other configurations, shapes and sizes of the image relay adapter 105 can be provided similar to those discussed with reference to the image relay adapter 30 with reference to Figures 1-4. Alternatively, the image relay adapter 105 can be formed of other materials including various polymer materials as described previously.

The image relay adapter 105 has threaded connectors in the outlet 110 which releasably connect with the threads in the camera. The image relay adapter 105 also has a ridge in the inlet 108 which connects with the lens assembly 25 as described with reference to the embodiment of Figures 1-4. Other connectors can be provided to releaseably connect the image relay adapter 105 with the camera 102 and the lens assembly 25 similar to those discussed with reference to the image relay adapter 30 in Figures 1-4, the discussion of which is incorporated by reference herein. . The image relay adapter 105 includes an image relay system (not shown) similar to that described with reference to the embodiment having the image relay adapter 30, the discussion of which is also incorporated by reference herein. The lens assembly 25 focuses light into an image which is transmitted into the inlet 108 of the image relay adapter 105. The inlet of the image relay adapter is positioned in the diverging beam after focus of the wide angle element. The focused light forms an image which is relayed through the optics of the image relay system in the body 106 such that a replica image is relayed through the outlet 110 of the image relay adapter 105. An image plane is preferably located adjacent the outlet 110 of the image relay adapter 105. Thus, a real image is relayed from the projector 20 through the inlet 108 to the outlet 110 of the image relay adapter 105.

The camera 102 receives the image formed by the focused light in a form whereby the image acquisition device can capture the replica image in a form suitable for hemispherical projection at an angle of at least 160° without spatial distortion.

Alternatively, the inlet of the image relay adapter can be located in the converging beam before the focus of the wide angle element of the lens assembly or the like. Referring to Figure 6, a still further embodiment of the optical projection system 120 having an image relay adapter 125 is illustrated. A film camera of the motion picture type 122 is releasably connected with the image relay adapter 125. The connection of the motion picture camera 122 with the outlet 130 of the image relay adapter 125 is similar to that described with reference to the still camera 102 and image relay adapter 105 of Figure 5, the discussion of which is incorporated by reference herein. . A lens assembly 25 as described with reference to the embodiments of Figures 1 to 5 is releasably connected with the inlet 108 of the image relay adapter 125 in a connection similar to that described with reference to Figures 1-5. The image relay adapter 125 contains a body

126 and an image relay system (not shown) positioned in the body 126. The body 126 is similar to the body 106 described with respect to Figure 5. The image relay system is similar to the image relay systems described with reference to the image relay adapter 30 of Figures 1-4 and the image relay adapter 105 of Figure 5. These discussions are thereby incorporated by reference herein.

The image relay adapter 125 functions in a similar manner to the image relay adapter 105. The lens assembly 25 focuses light into the inlet 128 of the image relay adapter 125. The focused light forms an image which is relayed through the optics of the image relay system in the body 126 of the image relay adapter 125 such that a replica image is relayed to the outlet 130 of the image relay adapter 125. An image plane is preferably located adjacent the outlet 130 of the image relay adapter 125. Thus, a real image is relayed from the lens assembly through the inlet 128 to the outlet 130 of the image relay adapter 125. The motion picture camera 122 receives the image formed by the focused light in a form whereby the image acquisition device can capture the image in a form suitable for hemispherical projection at an angle of at least 160° without spatial distortion. Alternatively, the light can be transmitted into the image relay adapter without focusing an image in the image relay adapter.

The image relay adapters 105 and 125 shown in Figures 6 and 7 facilitate use of a wide field of view lens assembly or other wide angle elements with various image acquisition devices. A variety of sizes, shapes and configurations of modular image relay adapters can be provided to be utilized with a single lens such as the lens assembly 25 and a variety of image acquisition devices. Suitable other image acquisition devices include various other film or digital cameras including, but not limited to, charged coupled devices, 35 mm single lens reflex cameras and film movie cameras . A kit of modular image relay adapters can be provided which facilitate the acquisition of real images from various environments for hemispherical projection on a hemispherical surface inner surface of a dome. Such a kit can be provided for use with a single lens assembly and a plurality or variety of image acquisition devices, including still cameras and motion picture cameras. Such images can be acquired using the optical projection system including the image relay adapter as described with reference to Figures 5 and 6. Such acquired images can then be projected on the truncated spherical inner surface of a dome or curved hemispherical surface using the optical projection system 10 according to the present invention described with reference to Figures 1-4.

Methods of optical projection utilizing the optical projection system 10 having an image relay adapter such as the image relay adapter 30, are provided according to the present invention. In one embodiment of these methods, an image is formed in an image forming location 70, shown at the projector in Figure 1, which is offset a predetermined distance from the center of curvature 17 of the inner surface 16 of the dome 15 to an image relay location 72. The image is formed including an array of image pixels suitable for radial projection onto a hemispherical surface. The array of image pixels moves from the image forming location 70 such that a replica image is received in the image relay location 72. The replica image is then projected by an optical projection system, for example a lens assembly 25, whose exit pupil is located near or, more preferably at, the center of curvature 17 of the truncated spherical inner surface 16 of the dome 15 for viewing. The array of image pixels are projected onto the inner surface 16 of the dome 15 at a projection angle of at least about 160 degrees without spatial distortion. In the optical projection system 10, the image also moves from the image forming location 70 to the image relay location 72 and is then projected from image projecting location 74 onto the inner surface 16 of the dome 15 in a hemispherical projection having constant angular separation between adjacent pixels of the array of image pixels. The array of image pixels is projected such that the hemispherical projection can be projected onto domes of varying radii without the need for correction for spatial distortion.

The optical projection systems and methods having an image relay adapter, including those utilizing an image relay adapter, facilitate viewing of centrally projected hemispherical projections in a dome. Further, the light weight and ease of assembly enhance the ease of use of the optical projection system according to the present invention. Thus, a optical projection system having an image relay adapter is provided which is lightweight, easy to assemble and of a lower cost than traditional planetariums and large scale, permanent flight simulators. In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.

Claims

THAT WHICH IS CLAIMED:

1. An optical projection system comprising: an image source including an array of image pixels; an image relay adapter comprising: a body including an inlet operatively connected with said image source and an outlet separated by a predetermined distance from said inlet ; and an image relay system in said body which receives said array of image pixels from said image source and relays said array of image pixels from said inlet to said outlet; and a hemispherical projection system operatively connected with said outlet of said image relay adapter, wherein said hemispherical projection system projects said array of image pixels from said image relay adapter onto a truncated spherical surface at a projection angle of at least 160 degrees.

2. An optical projection system as defined in Claim 1, wherein said hemispherical projection system projects said array of image pixels into a hemispherical projection having constant angular separation among adjacent image pixels.

3. An optical projection system as defined in Claim 2, wherein said optical projection system projects said array of image pixels into a hemispherical projection suitable for projection onto truncated spherical surfaces of varying radii without requiring spatial distortion correction of said array of image pixels .

4. An optical projection system as defined in Claim 1, wherein said hemispherical projection system further comprises : a lens assembly which receives said array of image pixels from said image relay adapter and projects said array of image pixels received into a hemispherical projection at a projection angle of at least 160 degrees.

5. An optical projection system as defined in Claim 4, wherein said lens assembly projects said array of image pixels into a hemispherical projection having constant angular separation among adjacent image pixels .

6. An optical projection system as defined in Claim 1, further comprising a dome including a truncated spherical inner dome surface, wherein said hemispherical optical projection system is located at the center of said dome to radially project said array of pixels onto said inner dome surface.

7. An optical projection system as defined in Claim 1, further comprising a dome including a truncated spherical inner dome surface, wherein said hemispherical optical projection system includes an exit pupil located substantially near the center of curvature of the dome.

8. An optical projection system as defined in Claim 6, wherein said image source is remotely positioned in said dome a sufficient distance from said lens assembly so as to eliminate sight obstruction for viewers within said dome .

9. An optical projection system as defined in Claim 1, wherein said image relay includes an elongate body having said outlet generally opposite said inlet.

10. An optical projection system comprising: an image source including an array of image pixels; an image relay adapter comprising: a body including an inlet operatively connected with said image source and an outlet separated by a predetermined distance from said inlet; and an image relay system in said body which receives said array of image pixels from said image source and relays said array of image pixels from said inlet to said outlet; and a hemispherical projection system operatively connected with said outlet of said image relay adapter, wherein said hemispherical projection system projects said array of image pixels into a hemispherical projection having constant angular separation among adjacent image pixels onto a truncated spherical surface.

11. An optical projection system as defined in Claim 10, wherein said optical projection system projects said array of image pixels onto truncated spherical surfaces of varying radii without requiring spatial distortion correction of said array of image pixels .

12. An optical projection system as defined in Claim 10, wherein said hemispherical projection system further comprises: a lens assembly which receives said array of image pixels from said image relay adapter and projects said array of image pixels received into a hemispherical projection having constant angular separation among adjacent image pixels.

13. An optical projection system as defined in Claim 10, further comprising a dome including a truncated spherical inner surface, wherein said hemispherical projection system is located at the center of said dome to radially project said array of pixels onto said inner dome surface.

14. An optical projection system as defined in Claim 10, further comprising a dome including a truncated spherical inner surface, wherein said hemispherical projection system includes an exit pupil positioned substantially near the center of curvature of the inner surface of the dome.

15. An optical projection system as defined in Claim 13, wherein said image source is remotely positioned in said dome a sufficient distance from said lens assembly so as to eliminate sight obstruction for viewers within said dome .

16. An optical projection system as defined in Claim 10, wherein said image relay includes an elongate body having said outlet generally opposite said inlet .

17. An optical projection system comprising: a dome including a truncated spherical inner surface; an image source positioned a predetermined distance from the center of curvature of said dome comprising an array of image pixels; an image relay adapter comprising: an elongate body including an inlet operatively connected with said image source and an outlet separated from said inlet a predetermined distance; and an image relay system in said elongate body which receives said array of image pixels from said image source and relays said array of image pixels from said inlet to said outlet; and a hemispherical projection system mounted at the center of said dome and operatively connected with said image relay adapter, said hemispherical projection system projects said array of image pixels onto the truncated spherical inner surface of the inner surface of the dome .

18. An optical projection system as defined in Claim 17, wherein said hemispherical projection system radially projects said array of pixels onto said inner dome surface at a projection angle of at least 160 degrees.

19. An optical projection system as defined in Claim 17, wherein said hemispherical projection system projects said array of image pixels into a hemispherical projection having constant angular separation among adjacent image pixels suitable for projection onto truncated spherical surfaces of varying radii without requiring spatial distortion correction of said array of image pixels.

20. An optical projection system as defined in Claim 17, wherein said optical projection system is a lens assembly mounted at the center of the dome .

21. An optical projection system as defined in Claim 17, wherein said optical projection system includes a lens assembly having an exit pupil located substantially near the center of curvature of the inner surface of the dome .

22. An optical projection systems as defined in Claim 17, wherein said image source is remotely positioned in said dome a sufficient distance from said lens assembly so as to eliminate sight obstruction for viewers within said dome.

23. An optical projection system comprising: an image forming system which forms an image suitable for radial projection onto a truncated spherical surface; and an image relay adapter comprising: a body including an inlet releasably connected with said image forming system, and an outlet separated from said inlet by a predetermined distance, and an image relay system in said body which receives said image from said image forming system at said inlet and relays said image from said inlet to said outlet such that a replica image is received at said outlet.

24. An optical projection system as defined in Claim 23, wherein said image forming system forms an image suitable for radially projecting into a hemispherical projection at a projection angle of at least 160 degrees without requiring spatial distortion correction.

25. An optical projection system as defined in Claim 24, wherein said image forming system comprises: a lens assembly which focuses light into said inlet of said image relay adapter for forming an image for hemispherical projection at a projection angle of at least 160 degrees without requiring spatial distortion correction, and; wherein said optical system further comprises : an image acquisition device operatively connected with said outlet of said image relay adapter, said image acquisition device acquires said focused light from said outlet of said image relay adapter in a replica image to said image formed by said focused light by said lens assembly, wherein said image is suitable for hemispherical projection at a projection angle of at least 160 degrees without requiring spatial distortion correction.

26. An optical projection system as defined in Claim 25 wherein said image acquisition device is a still camera.

27. An optical projection system as defined in Claim 25, wherein said image acquisition device is a motion picture film camera.

28. An optical projection system as defined in Claim 23, wherein said image forming system forms an image having an array of image pixels having constant angular separation among adjacent pixels.

29. An optical projection system as defined in Claim 28, wherein said image forming system further comprises, an image source comprising an array of image pixels; and wherein said optical system further comprises: a lens assembly operatively connected with said outlet of said image relay adapter which receives said array of image pixels from said image relay adapter and projects said array of image pixels received into a hemispherical projection having constant angular separation among adjacent image pixels such that said array of image pixels is suitable for projection onto truncated spherical surfaces of varying radii without requiring spatial distortion correction of said array of image pixels.

30. An optical projection system as defined in Claim 28, wherein said image forming system further comprises: an image source comprising an array of image pixels; and wherein said optical system further comprises: a lens assembly operatively connected with said outlet of said image relay adapter which receives said array of image pixels from said image relay adapter and projects said array of image pixels received into a hemispherical projection at a projection angle of at least 160 degrees without requiring correction for spatial distortion.

31. An optical projection system as defined in Claim 29, further comprising: a dome including a truncated spherical inner dome surface, said lens assembly being mounted at the center of said dome to radially project said array of pixels onto said inner dome surface.

32. An optical projection system as defined in Claim 30, further comprising: a dome including a truncated spherical inner dome surface, wherein said lens assembly is mounted at the center of said dome to radially project said array of pixels onto said inner dome surface .

33. An optical projection system as defined in Claim 29, further comprising: a dome including a truncated spherical inner dome surface, said lens assembly including an exit pupil which is positioned near the center of curvature of the dome .

34. An optical projection system as defined in Claim 23, wherein said image relay adapter is releasably connected with said image forming system.

35. An optical projection system comprising: a lens assembly which focuses light into an image suitable for radial projection onto a hemispherical surface at a projection angle of at least 160 degrees without spatial distortion; an image relay adapter comprising: a body including an inlet operatively connected with said image source and an outlet opposite said inlet; and an image relay system in said body which receives said focused light from said lens assembly and relays said focused light from said inlet to said outlet such that a replica image is received at said outlet; and a camera operatively connected with said outlet of said image relay adapter which acquires said focused light replica image from said outlet of said image -relay adapter suitable for radial projection onto a truncated spherical surface at a projection angle of at least 160 degrees without spatial distortion in a replica image to said image focused by said lens assembly.

36. An optical projection system as defined in Claim 35, wherein said camera is a film motion picture camera.

37. An optical projection system as defined in Claim 35, wherein said camera is a digital camera.

38. An optical projection system as defined in Claim 35, wherein said camera is a single lens reflex camera.

39. A method of hemispherical optical projection comprising the steps of: forming an image including an array of image pixels suitable for radial projection onto a truncated spherical surface in an image forming location separated from the center of curvature of a dome and out of the line of sight of viewers in the dome; relaying the formed image to a replica image at an image relay location; projecting the replica image from an image projection location near the center of curvature of the dome on the truncated spherical inner surface of the dome for viewing.

40. A method of hemispherical optical projection as defined in Claim 39: wherein said image forming step further comprises: forming the array of pixels in the image forming location in a form suitable for projection onto a truncated spherical surface at a projection angle of at least 160 degrees; and wherein said image projecting step further comprises projecting said array of pixels onto the truncated spherical inner surface of the dome at a projection angle of at least 160 degrees, the image projected being a replica image to the image formed in the image forming location and relayed to the image relay location.

41. A method of hemispherical optical projection as defined in Claim 39, wherein said image projecting step further comprises projecting said array of pixels onto the truncated spherical inner surface of the dome with the array of image pixels having constant angular separation among adjacent image pixels, the image projected being a replica image to the image formed in the image forming location and relayed to the image relay location.