CA1059361A - Method and apparatus for taking or projecting panoramic views - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A method of, and apparatus for, the shooting or projection of a panoramic view wherein an image is formed purely by refraction and while utilizing a single objective having an essentially vertically directed optical axis. The objective has a predetermined viewing eye and a light impervious, non reflecting cover arranged of a central portion of the viewing angle of the objective in order to mask a coherent bundle of light rays along the axis and an element situated in the masked area for supporting the take-up device or camera. In taking or projecting a panoramic view a vertically oriented fish-eye lens is used. A two-dimensional panoramic view forms a ring within which the image of the horizon is encompassed. The projection takes place on?o either a cylindricnl screen or a segment of a sphere, situated substantially axial with reference to the lens.

Description

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BACKGROUND OEI TEIE INVENTION

The present invention relates to a new and improved method of shooting or taking or projecting a panoramic view and ~ -also pertains to apparatus for the performance of the aforesaid method. - .
~ . ., The heretofore known techniques and equipment for taking a panoramic picture and projecting such panoramic picture, for instance as taught in United States patent 3,118,340 or German patent 1,135,677, usually possess at least one of two considerable drawbacks. On the one hand, such reside in the use of a multiplicity of cameras and reproduction devices and, on the other hand, in the use of optical reflectors. The first-mentioned drawback --apart from the exceptionally great expenditure in equipment-- is associated with the disadvantage that during reproduction of the picture or image problems arise with respect to the image eage, encompassing such different matters as those relating to image stablization, the color uniformity and illumination uniformity of all projected images, or also the portrayal of straight lines in bent configuratlon which is nec-essary at the edge location. In the case of motion pictures there are also present synchronization problems. The use of reflectors in turn require the use of generally a sensitive, some-times also bulky or complicated reflecting surface which possibly possesses an aspherical shape. Through the use of total reflect-ing surfaces it is possible, as taught in Swiss patent 451,548, . . .' ~ 2 ~ ~

.. 1()59 61 to eliminate the sensitivity of the reflector coatlng, but the special panorama ob~ective required for this purpose possesses t aspherical surfaces, appreciably impairing the economies thereof, especially when there is considered the relatively small numbers which can be commercialized.

SUMMAP~Y OF THE INVENTION
: . ' It is a primary object of the present invention to overcome the aforementioned drawbacks of the prior art.

To that end the method of this development is manifested by the features that the image is formed purely refractively and while utilizing a single objective possessing essentially vertically directed optical axis.
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An exemplary embodiment of apparatus for carrying out the method is manifested by the features of a light impervious non-reflecting cover which is arranged in a central portion of ~;
the field of view of the objective in order to mask or stop a coherent beam or bundle of light containing the axis.

The invention affords quite a number of advantages.
Firstly, there are overcome the image edge- and synchronization-problems which arise when using a number of objectives and thus a number of apparatuses and image carriers. Moreover, there are not required any optical reflector surfaces, and additionally, -- ~ 1059361 :~

it is possible to use appropriately dimensioned objectives of the conventional :.`
fisheye-type, which considerably improves -the economies of the method. This is especially so sonce the changes which are to be carried out at conventional camera- and reproduction apparatuses, can be carried out simply and in-expensively, and moreover the apparatus proposed for the performance of the .
method as contemplated by the invention is equally re:Latively inexpensive. ~;
According to the invention there is provided a method of taking or projecting a panoramic view comprising the step of utili~ing a vertically :~
oriented fish-eye lens the larger viewing angle of which exceeds 2~ steradians, whereby the two-dimensional panoramic image essentially ~orms a ring within the width of which is located the image of that part of the panorama which .`
corresponds to the hori~on, the projection being performed onto a screen .~;
which is either cylindrical or a segment of a sphere and substantially coaxial with respect to the lens. ~.
According to another aspect o:~ the invention there is provided an apparatus for taking or projecting a panoramic view, comprising a objective possessing an essentially vertically directed optical axis, said ~ :
obJective having a predetermined viewing angle, a light impervious, non- .` ;
reflecting cover arranged at a central portion of the viewing angle of the ~ .
obJective in order to mask a coherent bundle of light rays containing the .: ~
axis, an intermediate element located at the side o~ the objec-tive having . :
the larger viewing angle, said intermediate element having at least one axially symmetrical, rigid, transparent and a~ocal element located in a non- : .
masked part of the viewing angle in order to mechaincally connect a -take-up `~ .
device or projection device located externally of the larger viewing angle o~ the objective with elements of the device located within the masked part of such angle. ~.
BRIEF DESCRIPTION OF THE DRAWINGS :
The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to .
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lOS9361 i the following detailed description thereof. Such description makes reference .,~
to the annexed drawings wherein~
Figure 1 is a schematic view o~ a possible orientation of the .'. :
shooting or take-up camera;
Figure 2a schematically illustrates an arrangement for reproducing the panoramic image taken with the camera of Figure 1~
Figure 2b illustrates a ~urther possible arrangement of the projector and screen for reproducing the lmage or picture taken with the camera of Figure l; .~, ,; . ~;, ,.

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Figure 3 schematically illus-trates the position of an image upon an image carrier;
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Figure 4 illustrates a meridian plane for a preferred embodiment of the method; and . ~""", Figure 5 is a schematic illustration of an exemplary embodiment of apparatus for carrying out the method~ -.' . . ....
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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Describing now the drawings, Figure 1 schematlcally illustrates the use of a so-called fisheye objective for shooting or taking a panoramic view. The objective 1 has an angular lens field or image angle of 220 . For shooting the picture or image there is used of such image angle of 220 approximately the marginal sides, shown in shaded lines, namely the two fields each amounting to about 35 , and a central region of about 150 is covered or masked by a non-reflecting, preferably black surface 3.

In order to obtain a panoramic image or picture there ~-is used the camera, generally designated by reference character 2, for instance a Mitchell camera, and which camera is directed perpendicularly either upwardly or downwardly. Both possibilities are equal to one another, and for individual situations the one or the other can provide particular advantages. In order to simplify-the disclosure there will be hereinafter basically only ~ J~ k .
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considered the second possibility of arranging the camera.

Figures 2a especially shows a possibility of carrying out a projection of the image which has been shot by means of a projector 6 secured to the ceiling of a projection room or the like and which projector 6 is downwardly directed. Just as was the case for the take-up or shooting camera, the projector 6 is provided with a fisheye objective 6a having an aperature angle of 220. The latter projects the image upon a substantially circular-cylindrical image screen 7 arranged concentrically about its aY~is ~ the thus projected image then being observed by the viewer or observer as generally indicated by re~erence character 8. In order to avoid the effects of stray light it is recommended to use a cover 9, analogous to the surface 3, over the central region of the aperture angle of the projection ob-jective 6a. The projector 6, as shown in Figure 2a, can be secured directly at the specially constructed ceiling of the projection room, which can possess a projection cabin 10, or it can be suspended therefrom, or it can also be mechanically connected at the side o the objective with a lower situated stand or tripod, as will be discussed more fully hereinafter in conjunction with the arrangement of Figure 5.

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Figure 2b illustrates a further and preferred arrange-ment for image reproduction. Although the general construction and arrangement corresponds to that illustrated in Figure 2a, in this case the proiection cabin 30 does not extend into the pro-., ~,, ' ~ l / . ~ .
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~0593t~1 j~ction room, rather is located above the ceiling thereof. More- j over, the object which was shot through an angle amounting in toto to 220 (Figure l) must be imaged within an angle of about 180 , and this can be readily realized with an appropriately dimensioned objective. The non-employed central region thereof, with an image height of about 35, amounts to appro~imately llO instead of for instance 150 as in Figure l. The inclination of the projection surface relative to the central beams 34 of the shaded projection angle of 35 can be taken into account by appropriate correction of the objective. For reasons of sound insulation i.t is advantageous to rigidly imbed the projection objective 31 in the ceiling of the projection or viewing room or the like. The relatively heavy projection apparatus 32 can be moved by the operator up and down along vertically extending rails 33, there being provided a centering pin or equivalent structure for maintaining an exact mutual position of the objectiv~
and apparatus when such is in the lowermost position, that is to say in the projection position P. A commercially available lamp of 25 kW or greater can be used for illuminating the entire screen.
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Figure 3 illustrates the circular ring-shaped configur-ation of a panoramic picture occupying the shaded surface and appearing upon an image carrier. The inner diameter A and the outer diameter B of the circular ring correspond to one-half of the viewing image angle e = 75 and e = 110 which the object field bounds during shooting. The empty central circle correspondc to the cover surface 3.

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i.' the panoramic image reference will be made at this point to ~` Figure 4. Since the employed object fie:Ld angle of the fisheye objective which is used for shooting the image exceeds 180, in .
order to obtain a clear picture or image r the axial spacing Y :~
J,. of the image point P as a function of the angle e of the ~:.
associated, object-side primary beam, cannot be determined by one :
of the usually employed equations: : .
. Y = C tan e, or Y = C sin e wherein C is a dimension-related constant. Therefore, for carrying out the method of the invention there is preferably used . an objective which follows the image law expressed by the .~. following equation: ;.:
Y = c.e. -r',,, .
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,,.jf When practicing the method there occur essentially two ,.l, problems which are governed by the fact that the entire space :.
through the useful object- or image angle shown shaded in Figures 1 and 2 is cut into two halves. If for instance, as ~hown in ; Figures 1 and 2, the camera and reproduction device are downwar~ly directed, then there can be provided at the ceiling of the pro- ~:~
(~ jection or screening room (Figures 2a and 2b) a projection room .~ , 10 or ~, from which location there is accessible the reproduction device 6 which is located at the floor thereof without having to .
penetrate the useful image angle. Generally however, especially for shooting pictures in the open, the camera 2 or other suitable take-up dev.ice shown in Figure 1 must be supported from belo~, so ., .
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that it is necessary to penetrate through the ob]ect angle.
Figure 5 schematically illustrates an exemplary embodiment of an apparatus sui~able for this purpose. Such consists essentially of a transparent element 17 which is ~abricated for instance o~
glass or plexiglass and coaxially arranged with respect to the objective 16. l~his element, although located in the part of the object angle which is used, forms however an afocal system. In the illustrated embodiment this element possesses a spherical shell-shape, but it can also possess other shapes, for :instance it can be constructed as a cylindrical- or truncated cone-shell.
What is only of importance is that this afocal system possesse~s a suficlent mechanical strength in order to be able to for instance tra~smlt the forces required for supporting the camera or take-up device 15 from the non-used part of the object angle to the camera. Both for mechanical as well as optical reasons there have been found to be satisactory as the supporting element '~ ~P/c~ /o~s a linear plcxiglass cylinder which is coaxial with respect to the optical axis. With appropriate construction of the lens socket it is, however, also possible to support the apparatus directly at the part of the front lens surface which is covered in any case, so that there is avoided all impairment of the light rays.
This not particularly shown unconventional, but simple solution is also of significance because the weight of the shooting camera and an associated 220 fisheye objective are of the same order of magnitude and the forces exerted upon the connection oE both therefore do not depend very much upon which of both is supported.
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In the event that a number of coaxial afocal elements 17 are stacked within one another, then they can transmit - for instance by carrying out a mutual rotation-- also the forces and moments which are necessary for diaphragm adjustment, tripping of the device and so forth.
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In the embodiment of Figure 5 the element 17 serves as the supporting element for the entire take-up device or camara 15 which is vertically downwardly directed, so that such can bear upon a stand or tripod 20 or equivalent structure. For this purpose the ele~lent 17 downwardly merges into a non-transparent carrier or support 1~ which itself bears upon the stand 20. The spherical-shaped surface 19 of the carrier or support 18 which is directed towards the objective 16 is blackened to avoid the effect of stray light. At the other side, i.e. the side towards the top of Figure 5, the element 17 is rigidly co~nected with a support or carrier frame 21 at which there is secured the camera 15 with the screws 22 or equivalent structure. The entire arrange ment allows shooting panoramic images or pictures with downwardl~
directed camera or the like, without the supporting elements, which support the camera from below, appearing upon the image.
The proposed apparatus of course is suitable for making both moving pictures as well as still pictures upon any desired image or picture carrier. As the camera there can be used, for instance ~`j a Mitchell camera provided with a so-called rack-over for image , adjustment.

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Final.ly, it is still remarked that the use of a multi~
plicity of coaxial, afocal elements renders it posslble, by mutual movement thereof, for instance also during shooting of a moving picture, to control the camera from the side of the stand without impairing the images or pictures which are being talcen~ Moreover, for reducing disturbing refractions and reflections, it can be advantageous to fill the space between the a..ocal elements, and which space is held as small as possible, with a liquid having a similar refractive index as the material of such elements.
Consequently, and while for such shooting of images generally there ls provided a wireless control of the camera, if necessary, there can be transmitted aontrol- or drive forces also mechanicall to the camera or take-up device.
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While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following ::.
claims. ACCORDINGLY, : ~

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of taking or projecting a panoramic view comprising the step of utilizing a vertically oriented fish-eye lens the larger viewing angle of which exceeds 2? steradians, whereby the two-dimensional panoramic image essentially forms a ring within the width of which is located the image of that part of the panorama which corresponds to the horizon, the projection being performed onto a screen which is either cylindrical or a segment of a sphere and substantially coaxial with respect to the lens.

2. The method as defined in claim 1, wherein the image associates a conjugate point to a first point and which first point is located at infinity at the side of the objective having the largest viewing angle, and the spacing of said conjugate point from the optical axis is proportional to the inclination angle of the main beam with the axis associated with the first point.

3. The method as defined in claim 1, including the step of providing a wireless control for the image take-up camera.

4. An apparatus for taking or projecting a panoramic view, comprising an objective possessing an essentially vertically directed optical axis, said objective having a predetermined viewing angle, a light impervious, non-reflecting cover arranged at a central portion of the viewing angle of the objective in order to mask a coherent bundle of light rays containing the axis, an intermediate element located at the side of the objective having the larger viewing angle, said intermediate element having at least one axially symmetrical, rigid, transparent and afocal element located in a non-masked part of the viewing angle in order to mechanically connect a take-up device or projection device located externally of the larger viewing angle of the objective with elements of the device located within the masked part of such angle.

5. The apparatus of claim 4, wherein the cover masks a solid angle of at least ?/2 steradians of the viewing angle.

6. The apparatus of claim 4, wherein the intermediate element is cylindrical.