Abstract:
Cameras are positioned so that at least a portion of the field of view of at least one camera is redirected by a reflective surface. Images from these cameras are merged to produce a composite image while disregarding at least a portion of a camera&#39;s field of view such that there is at least one blind region in the composite field of view. Advantageously, such blind regions can be made to encompass edges of mirror surfaces that would otherwise produce image artifacts in the composite image; this can be accomplished without introducing gaps in the angular span of the composite field of view. Data representative of the composite image is stored in a memory from which it may be retrieved selectively using a control means to display a portion of the composite image. The image and control data may be transmitted over a communication network to facilitate remote control and display.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation of commonly assigned U.S. Patent application entitled “Panoramic Viewing System With Shades”, Ser. No. 09/431,400, filed Dec. 27, 1999, which is a continuation of commonly assigned U.S. Patent application entitled “Panoramic Viewing System With Offset Virtual Optical Centers”, Ser. No. 08/946,443, filed Oct. 7, 1997, which issued as U.S. Pat. No. 6,111,702 on Aug. 29, 2000, which is a continuation-in-part of commonly assigned U.S. Patent application entitled “Spherical Viewing/Projection Apparatus”, Ser. No 08/565,501, filed Nov. 30, 1995, which issued as U.S. Pat. No. 6,115,176 on Sep. 5, 2000; and is related to commonly assigned U.S. Patent Application entitled “Panoramic Viewing Apparatus”, Ser. No. 08/431,356, filed Apr. 28, 1995, which issued as U.S. Pat. No. 5,745,305 on Apr. 28, 1998 and to commonly assigned U.S. Patent Application entitled “Method and System for Panoramic Viewing”, Ser. No. 08/431,354, filed Apr. 28, 1995, which issued as U.S. Pat. No. 5,990,934 on Nov. 23, 1999. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a viewing system; more particularly, a spherical viewing system.  
           [0004]    2. Description of the Related Art  
           [0005]    In an effort to operate more efficiently, it is desirable to perform some tasks using telepresence. Telepresence refers to providing visual or other types of sensory information from a device at a remote site to a user that make the user feel as if he/she is present at the remote site. For example, many businesses now hold meetings using telepresence. Telepresence is also useful for distance learning and remote viewing of events such as concerts and sporting events. A more realistic telepresence is provided to a user by providing the user with the capability to switch between views, and thereby mimic, for example, looking around a meeting room.  
           [0006]    In the past, when several views were made available to a user, several cameras with different optical centers were used. Such a situation is illustrated in FIG. 1. FIG. 1 illustrates cameras  2 ,  4 ,  6  and  8  with optical centers  10 ,  12 ,  14 , and  16 , respectively. When the user decided to change views, he or she simply switched between cameras. In more sophisticated systems, when a user decided to change views, he or she was able to obtain a view from optical centers  10 ,  12 ,  14 , or  16  as well as from additional optical centers  18 ,  20 ,  22 ,  24  or  26 . Views associated with optical centers such as  18 ,  20 ,  22 ,  24 , and  26  were obtained by using views from the two cameras nearest to the selected optical center. For example, a view from optical center  18  was obtained by using the views from cameras  2  and  4  and interpolating between the two views so as to simulate a view from optical center  18 . Such procedures introduced irregularities into views. In addition, forming these interpolated views required a large amount of computational power and time, and thereby made this technique expensive and slow to respond to a user&#39;s commands. This computational overhead also limited the number of users that can simultaneously use the system.  
           [0007]    Other prior art discloses that the several views made available to a user can also be derived from a single wide-angle view that is created from multiple individual views captured by multiple distinct cameras. However, prior-art arrangements to create a single wide-angle view from multiple individual views have been unsatisfactory. In some arrangements, there is substantial parallax between the individual views, parallax that would lead to artifacts where the individual views would overlap or adjoin in any composite image; such artifacts are avoided in some cases by intentionally fragmenting the wide-angle view to have substantial gaps between individual images upon their display (e.g., U.S. Pat. No. 2,942,516). In some other arrangements, even though parallax between individual views may be minimal or absent, image artifacts remain and there is no suggestion on how to prevent these image artifacts from occurring where individual views would adjoin in any composite image (e.g., U.S. Pat. Nos. 3,118,340, 3,356,002, 4,890,314, 5,187,571). In some other arrangements, the number of individual cameras is limited to be no more than three and precise optical alignment of cameras and projectors is required to create a composite wide-angle image that is optical, rather than electronic, for all practical purposes precluding the use of such a composite image in providing multiple views to a user as described above (e.g., U.S. Pat. Nos. 2,931,267, 3,031,920, 4,890,314). Of particular relevance here are prior-art arrangements that use one or more mirrors with more than one camera to create a wide-angle composite image: One problem that has remained unaddressed in such arrangements is how to rid the composite image of image artifacts due to portions of individual images being captured off edges of mirrors (e.g., U.S. Pat. Nos. 2,931,267, 3,031,920, 3,118,340, 4,890,314, 5,187,571); further, even in those of such arrangements in which an attempt is made to reduce other image artifacts, which occur due to causes other than reflection off edges of mirrors and occur where individual images come together in a composite image, the arrangements and techniques proposed are limited to using no more than three cameras and are purely optical rather than electronic, requiring precise optical alignment of cameras and projectors and not lending themselves to providing multiple views to a user as described above (e.g., U.S. Pat. Nos. 2,931,267, 3,031,920). Some other prior art devices have no particular advantage with respect to acquiring a wide-angle field of view and also fail to avoid the above-mentioned image artifacts caused by portions of individual images being captured off edges of mirrors (e.g., U.S. Pat. Nos. 5,016,109, 5,194,959). These are just some of the drawbacks of the prior art that prevent it from being used to create high-quality composite wide-angle images that can be used to provide multiple views to a user as described above.  
         SUMMARY OF THE INVENTION  
         [0008]    One embodiment of the present invention provides an omnidirectional or panoramic viewer where several cameras have a common optical center. The cameras are positioned so that they each view a different reflective surface of a polyhedron such as a pyramid. This results in each camera having a virtual optical center positioned within the pyramid. The field of view of each of the cameras is merged with the individual fields of view of the other cameras and arranged to form a composite field of view which is a continuous 360 degree view of an area when taken as a whole. The user can sweep through 360 degrees of viewing, where each view has the same or nearly the same optical center, by simply using the output of one camera or the combination of two cameras without requiring the computational overhead of interpolation used in the prior art. Such an arrangement may be used to enhance use of virtual meeting rooms by allowing a viewer to see the meeting room in a more natural format. This format corresponds closely to a person sitting in the actual meeting who simply turns his or her head to change the view at a particular time.  
           [0009]    In another embodiment of the present invention, a nearly spherical view is provided to a user by placing a camera with its optical center at the common virtual optical center of the viewer. In order to enhance the spherical view, the camera at the common virtual optical center may use a wide angle lens.  
           [0010]    In still another embodiment of the invention, the cameras are positioned so that their effective optical centers are offset from each other. The offsets produce narrow blind regions that remove image distortions received from the edges of the pyramid&#39;s reflective surfaces. Additionally, planar shades that extend in an outward direction are positioned in the blind regions.  
           [0011]    In yet another embodiment of the present invention, the viewing device may include any type of image transducer or processing device. If the image transducer or processing device is a camera or other type of image capture device, a panoramic or spherical image is captured for the user, and if the image transducer or processing device is a projector or other type of image producing device, a panoramic or spherical image is produced for the user. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0012]    [0012]FIG. 1 illustrates a prior art multiple camera viewing system;  
         [0013]    [0013]FIG. 2 illustrates a four camera omnidirectional or panoramic viewing system using a four-sided pyramid with reflective surfaces;  
         [0014]    [0014]FIG. 3 illustrates how a reflective surface of the pyramid is used to provide each camera with a common optical center;  
         [0015]    [0015]FIG. 4 illustrates the top view of the pyramid illustrating the camera positions;  
         [0016]    [0016]FIG. 5 illustrates an eight-sided pyramid with reflective side surfaces;  
         [0017]    [0017]FIG. 6 is a top view of the pyramid of FIG. 5;  
         [0018]    [0018]FIG. 7 is a block diagram of a system to control data produced by the cameras;  
         [0019]    [0019]FIG. 8 illustrates the association between the data received from the cameras and the view presented to a user;  
         [0020]    [0020]FIG. 9 illustrates an addressing scheme for the memory of FIG. 7;  
         [0021]    [0021]FIG. 10 is a block diagram of the controller of FIG. 7;  
         [0022]    [0022]FIG. 11 illustrates using a telecommunications network to provide a selection of views to a plurality of users;  
         [0023]    [0023]FIG. 12 illustrates a second embodiment for providing a selection of views to multiple users over a telecommunications network;  
         [0024]    [0024]FIG. 13 illustrates the viewing system of FIG. 2 with a fifth camera;  
         [0025]    [0025]FIG. 14 illustrates a top view of the pyramid of FIG. 2 with displaced virtual optical centers; and  
         [0026]    [0026]FIG. 15 illustrates the pyramid of FIG. 14 with shades positioned in blind regions. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]    [0027]FIG. 2 illustrates a four camera system for providing a 360 degree view to a user, where the cameras each have a common virtual optical center within the pyramid. Pyramid  40  has reflective sides  42 ,  44 ,  46  and  48  and may be a hollow or solid structure. In a preferred embodiment, each of the reflective sides forms a 45 degree angle with a plane parallel to base  50  and passing through the vertex of pyramid  40 . Cameras  52 ,  54 ,  56  and  58  are associated with pyramid reflective surfaces  48 ,  42 ,  44 , and  46 , respectively. The cameras may be image gathering devices such as an optical scanner. As a result, camera  52  views a reflection from surface  48  to enable it to view objects in the direction of arrow  60 . Camera  54  views a reflection from surface  42  to view objects in the direction of arrow  62 . Camera  56  views a reflection from surface  44  to view objects in the direction of arrow  64 , and camera  58  views a reflection from surface  46  to view objects in the direction of arrow  66 . Each camera has a 90 degree field of view. The combination of the four cameras viewing reflections from their associated reflective surfaces on pyramid  40 , produce a 360 degree view of the area surrounding pyramid  40 . It is desirable to locate the optical center of each camera on a plane that is parallel to base  50  and intersects vertex  70  of pyramid  40 . Each camera&#39;s optical center should also be located on a line that passes through vertex  70  and is perpendicular to the base line of the camera&#39;s associated reflective surface. For example, the optical center of camera  54  is located on line  72 . Line  72  is perpendicular to base line  74  of reflective surface  42 . Line  72  is in a plane that passes through vertex  70  and is parallel to base  50 . Likewise, the optical center of camera  56  is positioned on line  76  which is perpendicular to baseline  78 , the optical center of camera  58  is positioned on line  80  which is perpendicular to base line  82 , and the optical center of camera  52  is positioned on base line  84  which is perpendicular to base line  86 .  
         [0028]    Each camera optical center is positioned on one of the above described lines at a distance X from vertex  70  and each camera has its optical axes or direction of view pointing perpendicular to base  50 . (The distance X should be such that the reflective surface reflects as much of the camera&#39;s field of view as desired; however, the defects in the reflective surface become more visible when the camera is moved closer to the reflective surface.) This positioning of optical centers results in the cameras sharing a virtual optical center located at position  90 . Virtual optical center  90  is located a distance X from the vertex  70  on a line that passes through vertex  70  and is perpendicular to base  50 .  
         [0029]    [0029]FIG. 3 illustrates another view of pyramid  40  where only camera  54  is shown for the sake of simplicity. Camera  54  is positioned on line  72  so as to have a virtual optical center at position  90  within pyramid  40 . If camera  54  has a 90 degree field of view in the direction perpendicular to base  50 , and if the optical center of camera  54  is at a distance of X from vertex  70  along line  72 , camera  54  has a 90 degree view in the direction of arrow  62 . In similar fashion, cameras  56 ,  58 , and  52  have 90 degree views in the direction of arrows  64 ,  66 , and  60 , respectively. This arrangement inexpensively produces a 360 degree field of view of an area because cameras with a 90 degree field of view have relatively inexpensive optics.  
         [0030]    [0030]FIG. 4 is a top view of pyramid  40 . FIG. 4 illustrates the placement of the optical center of camera  54  along line  72 . Line  72  should be in a plane that passes through vertex  70  and is parallel to base  50 . The line should also be perpendicular to base line  74  of pyramid  40 . The camera&#39;s optical center should be positioned a distance X from vertex  70  along line  72 . The distance X should be such that the reflective surface reflects as much of the camera&#39;s field of view as desired. Point  100  is located on base  50  at a position where a line from vertex  70  perpendicularly intersects base  50 . In a similar fashion, the optical centers of cameras  56 ,  58  and  52  are positioned the distance X along lines  76 ,  80  and  84 , respectively.  
         [0031]    [0031]FIG. 5 illustrates an eight-sided pyramid  120 . Pyramid  120  has reflective surfaces  122  where each of surfaces  122  forms a 45 degree angle with a plane that passes through vertex  130  and is parallel to base  124 . As with the four-sided pyramid of FIG. 2, each reflective surface of FIG. 5 may have a camera associated with it. Each camera&#39;s optical center is positioned on a line that is in a plane that passes through vertex  130  and is parallel to base  124 . The line is perpendicular to base line  132  of the reflective surface associated with the camera to be positioned. Using an eight-sided pyramid offers the advantage of using cameras with only a 45 degree field of view to obtain a 360 degree view. Cameras with only a 45 degree field of view have inexpensive optics and enable a 360 degree view to be constructed using relatively inexpensive components.  
         [0032]    [0032]FIG. 6 is a top view of pyramid  120 . As discussed with regard to FIG. 5, each camera&#39;s optical center is positioned along a line  134  which is in a plane that passes through vertex  130  and is parallel to base  124 . The optical centers are positioned a distance X along line  134  which is perpendicular to the appropriate base line  132 . Point  140  is on base  124  at the point of intersection between base  124  and a line that passes through vertex  130  and is perpendicular to base  124 .  
         [0033]    Pyramids having more or less reflective sides may be used. The advantage of using pyramids having a large number of sides is that cameras with moderate to small fields of view may be used. Cameras with moderate fields of view have relatively inexpensive optics. The number of sides used in a pyramid is somewhat limited by the cost of providing a large number of cameras. A 360 degree view of a scene may be provided using a pyramid having three reflective sides. It may be expensive to use only a three-sided pyramid in order to provide a 360 degree field of view. This embodiment of the invention uses three cameras each with a 120 degree field of view, and cameras with such a wide field of view use relatively expensive optical components.  
         [0034]    In applications where a full 360 degree view is not desired, it is possible to build a viewer that does not have a camera associated with each reflective surface of the pyramid.  
         [0035]    [0035]FIG. 7 illustrates a block diagram of a system for controlling data produced by the cameras of a viewing device such as the viewing device described in FIGS. 2 through 4. Cameras  52 ,  54 ,  56  and  58  obtain a 360 degree view of an area via their associated reflective surfaces of pyramid  40 . The image signal or output signal of cameras  52 ,  54 ,  56  and  58  are passed through analog to digital converters (A/D)  160 ,  162 ,  164 , and  166 , respectively. The output of the cameras can be thought of as a stream of pixels and the output of the A/Ds can be thought of as data representative of the pixels from the cameras. The output of the A/Ds are passed through mux  170 . Mux  170  allows the pixel data from each of the A/Ds to reach memory  172 . Controller  174  cycles the select lines of mux  170  so that the outputs of all of the A/Ds are stored in memory  172 . Mux  170  is switched at a rate that is four times the pixel rate of the cameras. If more or less cameras are used, the rate at which mux  170  is switched will be increased or slowed accordingly. It is also possible to eliminate mux  170  and to store the output of each A/D in a separate memory. Controller  174  is implemented using a microprocessor which provides control signals to counters that control the switching of mux  170  and counters used to provide addressing to memory  172 . The control signals to the counters include reset, enable and a starting offset.  
         [0036]    As a result of the pixel information being passed to memory  172 , memory  172  contains a 360 degree view of a scene. Pixel information stored in memory  172  is passed through digital to analog converter (D/A)  176  and to video display  178 . The actual portion of memory  172  that is passed to video display  178  via D/A  176  is controlled via user input device  180 . User input device  180  may be a common device such as a mouse, joystick, or keyboard. The user may simply lean a joystick to the right to shift his view to the right, lean the joystick to the left to shift the view to the left, or leave the joystick in the center to keep the view unchanged. Based on the input from user device  180 , controller  174  varies offsets and starting addresses that are used to provide addressing to memory  172 .  
         [0037]    [0037]FIG. 8 illustrates the relationship between the data provided by the cameras and the view available to the user. Since the cameras share a virtual optical center, the view can be thought of as a cylindrical view. Sector  200  can be thought of as representing the information provided by camera  52 , sector  202  can be thought of as representing the information provided by camera  54 , sector  204  can be thought of as representing the information provided by camera  56 , and sector  206  can be thought of as representing the information provided by camera  58 . The surface of the cylinder in each sector can be thought of as a collection of columns, where each column is composed of pixels. For example, sector  200  can be thought of as a collection of columns including columns  210 ,  212 ,  214  and  216 . Likewise, the output produced by camera  54  can be thought of as a collection of columns which include column  218  in sector  202  and the output of camera  58  can include columns such as column  220  in sector  206 . The column of pixels near the sector boundaries are closer together than the columns near the center of a sector. This occurs because the cameras capture the image on a plane while FIG. 8 shows the columns projected onto a cylindrical surface.  
         [0038]    [0038]FIG. 9 illustrates how memory  172  is divided to provide easy access to different views based on signals from user input device  180 . Sections  230 ,  232 ,  234  and  236  correspond to sectors  206 ,  200 ,  202  and  204 , respectively. Each of sections  230 ,  232 ,  234  and  236  can be thought of as a block within memory  172 . The blocks in memory  172  are broken into columns of sequential addresses. The first column of memory segment  230  corresponds to the first column of pixels of sector  206 . The number of memory positions associated with a column should be at least sufficient to have one location for each pixel in a particular column. For example, if a column of pixels from FIG. 8 includes 1000 pixels, each column associated with the memory segments of FIG. 9 should have at least 1000 locations. The number of columns associated with a particular memory segment should be at least equal to the number of columns associated with a particular section of the cylinder of FIG. 8.  
         [0039]    If a camera scans in a horizontal direction, sequential pixels are written in adjacent columns, but possibly different rows, of a particular memory segment by simply changing an offset to a counter generated address. The overall write address is generated by adding the offset to the counter&#39;s output. This offset is changed at the rate in which the horizontally scanned pixels are received. After a horizontal scan is completed, the counter is incremented and once again the offsets are changed at the horizontal scan rate. As a result, when addressing a particular segment of memory during a write cycle, the columns are addressed by changing the offset at the horizontal pixel scan rate, and incrementing the counter at the vertical scan rate. This type of addressing scheme is used for accessing columns within each memory segment. When addressing different memory segments during a write cycle, a write segment offset is added to the sum of the counter output and the column offset. The write segment offset permits addressing memory segments  230 ,  232 ,  234 , and  236 . The segment offset is changed at the same rate as mux  170  is switched.  
         [0040]    Pixel data is read from memory  172  in a similar fashion. The sum of a counter output and two sets of offsets are used to generate a read address. Once an initial starting column has been picked, the read address is generated by switching a read column offset at a rate that is equal to the horizontal scan rate of a video display. After reading one horizontal scans worth of data, the read counter is incremented and the read column offsets are changed at a rate equal to the horizontal scan rate of the display. As a result, the offset addresses are changing at the display&#39;s horizontal display rate and the counter is incremented at a rate equal to the vertical scan rate of a display. It is possible to read data out at a rate faster or slower than required by the video display; however, if read out faster, a buffer memory should be used, if read out slower the video display may appear choppy to the viewer.  
         [0041]    It should be noted that the cylindrical arrangement of pixels of FIG. 8 is typically displayed on a flat or nearly flat display. As a result, the image is displayed by compensating for converting between a cylindrical surface and a flat surface. This may be carried out using a simple conversion algorithm within a common digital signal processing integrated circuit. Methods for these types of conversions are well known in the art and can be found in “A Guided Tour of Computer Vision,” Vishvjit S. Nalwa, Addison-Wesley Publishing Co., Reading, Mass., 1993. It is also possible to carry out the conversion using a very high resolution display.  
         [0042]    It should be noted that if the view selected by a user corresponds exactly to the view of a particular camera, such as camera  52 , columns  240 - 248  are read from memory  170 . Column  240  is the first column in segment  232  and column  248  is the last column in segment  232 . If the user decides to move the view in a counter-clockwise direction, the start column will shift to the right so that the read operation begins at column  246  and ends at column  250 . It should be noted that column  246  is the second column associated with memory segment  232  which has the pixel data from camera  52 , and that column  250  is the first column of pixel data associated with camera  56 . As the user shifts the view, the starting column shifts in relationship to the user&#39;s commands. For example, if the user indicates that the view should shift in a counter-clockwise direction, the start column of FIG. 9 moves to the right, similarly, if the viewer indicates that the view should shift in a clockwise direction, the start column shifts to the left. As before, columns are addressed by using offsets, if the offsets involve moving between memory segments, a read segment offset is added to the sum of the column offset and counter output.  
         [0043]    It should be recalled that the columns near the sector boundaries of FIG. 8 are closer together. As a result, when the user commands a change in a view and when the border of that view is near a sector boundary, the start column changes by a larger number of columns for a given angular rotation of the view. Conversely, when the border of the view is near the center of the sector, the start column changes by a smaller number of columns for a given angular rotation.  
         [0044]    [0044]FIG. 10 illustrates a block diagram of controller  174 . Controller  174  includes microprocessor  270  and memory  272 . Memory  272  includes RAM and ROM. Processor  270  receives commands on line  274  from user input device  180 . Microprocessor  270  controls start, stop and reset of counter  276 . Counter  276  controls the select lines of mux  170 . Counter  276  counts at a rate that is four times the horizontal scan rate of the cameras. Write address generator  278  provides write addressing for memory  172 . Write address generator  278  includes a counter, register for storing offsets and adder for adding the offsets and counter output. Microprocessor  270  controls the offset selection and the counters used by write address generator  278 . The write addresses are formed as described with regard to FIG. 9. Read address generator  280  provides read addresses to memory  172 . Read address generator  280  includes a counter, register for storing offsets and adder for adding the offsets and counter output. As with write address generator  278 , microprocessor  270  controls the offset selection and the counters of read address generator  280 . Microprocessor  270  also controls the starting column used by the counters based on inputs provided on line  274  from user input  180 .  
         [0045]    The write and read addresses are provided to memory  172  separately if memory  172  is implemented using a two port memory. If memory  172  is implemented with a single port memory, the write and read addresses are multiplexed to memory  172 .  
         [0046]    [0046]FIG. 11 illustrates an embodiment where a panoramic viewer is used to provide views to several users over a communications network. In this embodiment, all of the columns of pixel data are read from memory  172  and placed on bus  300 . Buffer memories  302 ,  304 ,  306  and  308  receive the data from bus  300 . The buffer memories are enabled only when desired columns are available on bus  300 . The buffer memories then pass their information to modems  310 ,  312 ,  314  and  316 , which then provide the pixel data to telecommunications network  318 . Telecommunications network  318  then delivers the information from the modems to the users. In one example, a user receives information from modem  316  using modem  320 . Modem  320  then provides the pixel information that was in memory  308  to a local video memory  322 . Video memory provides the pixel information to display  324  for viewing. The user at this location controls the view using user input device  326  which may be a device such as a mouse, keyboard or joystick. Modem  320  transmits the user input device signals over telecommunications network  318  to modem  316  which then provides the signals to enable controller  330 . Enable controller  330  receives a signal from controller  174  that indicates which column is being read from memory  172 . When the appropriate column is available, the enable controller  330  enables the buffer memory  308  to receive the columns of data specified by the user input device signals received over the communication network. As discussed with regard to FIG. 9, enable controller  330  simply moves the start column based on signals from the user input device. In this embodiment, enable controller  330  enables the input to the buffer memory when the pixel data from the start column is on bus  300 . Enable controller  330  disables the input to the buffer memory when the total number of columns of pixels to be viewed are provided to the buffer memory. FIG. 11 illustrates a system where four users can individually control their viewing; however, more users may be accommodated by simply increasing the number of buffer memories, modems, and ports on enable controller  330 .  
         [0047]    [0047]FIG. 12 illustrates another embodiment in which multiple viewers can use the panoramic viewer. As the pixel data is read from memory  172 , all of the data is passed over telecommunications network  318  to telecommunications bridge  350 . The information from memory  172  is provided to bridge  350  via modem  344 ; however, the data may be passed to bridge  350  without use of modem  344  if a digital connection is made between memory  172  and bridge  350 . Bridge  350  then distributes all of the data received from memory  172  to each user in communication with bridge  350 . If bridge  350  provides analog link to users, a modem should be used at each user port. If the bridge has a digital link to the user ports, a modem is not required. In the case of an analog link, the data from memory  172  passes from modem  344  via bridge  350  to modem  360  at a user port. Modem  360  passes the pixel data to video memory  362 . Video memory  362  then passes the pixel information to video display  364  under control of a user via user input device  366 . User input device may be a mouse, joystick or computer keyboard. In this embodiment, the entire contents of memory  172  is fed to video memory  362 . The data read from memory  362  and passed to video display  364  is controlled using user input device  366  in a fashion similar to that which was described with regard to FIG. 9.  
         [0048]    [0048]FIG. 13 illustrates the viewing system of FIG. 2 with a fifth camera. Camera or image gathering device  400  is located in pyramid  40  with the optical center of camera  400  located at virtual optical center  90 . Camera  400  views objects in the direction of arrow  410 . It is desirable to provide camera  400  with a wide angle lens. The resulting wide angle view coupled with the views of the remaining four cameras, provides a nearly spherical view. If the cameras of FIG. 13 are replaced with image producing devices, the nearly spherical viewing system becomes a nearly spherical projection system. It should be noted that a camera or projection device may be placed at the virtual optical center of viewing/projection devices having pyramids with three, four or more sides. It should also be noted that edges  420  of the reflective surfaces should be beveled to avoid undesirable obstruction of camera  400 &#39;s field of view. It is also possible to avoid undesirable image artifacts from base edges  420  by moving camera or image processing device  400 . Device  400  should be moved so that device  400 &#39;s optical center is positioned away from virtual optical center  90  in the direction of arrow  410 . Device  400 &#39;s optical center should be positioned so that the device&#39;s field of view does not include edges  420 .  
         [0049]    [0049]FIG. 14 illustrates a top view of the pyramid of FIG. 2. In reference to FIG. 2, camera  52 ,  54 ,  56  and  58  have been moved upward in the direction of base  50 . As a result, virtual optical centers  500 ,  502 ,  504  and  506 , which correspond to cameras  52 ,  54 ,  56  and  58 , respectively, are moved away from virtual optical center  90 . It is desirable to move the virtual optical centers so that camera  52  captures an image between lines  508  and  510 , camera  54  captures an image between lines  512  and  514 , camera  56  captures an image between lines  516  and  518 , and camera  58  captures an image between lines  520  and  522 . This results in the cameras not capturing useful images from narrow planar shaped regions. In particular, planar regions  524 ,  526 ,  528  and  530  are not used by the cameras and form blind regions. This offers the advantage of removing portions of the cameras&#39; fields of view that are received from the edges of the reflective pyramid. Eliminating these portions of the fields of view alleviates the need to provide image processing that compensates for image artifacts at the edges. It is desirable to keep virtual optical centers  500 ,  502 ,  504  and  506  closely clustered so that planes  524 ,  526 ,  528  and  530  are only as thin as necessary to avoid edge artifacts. By maintaining such thin planes, the need to process the images at their common boundaries is removed while minimizing the noticeable effect seen by a user.  
         [0050]    From the foregoing description, it is readily apparent that moving the virtual optical centers outward, as in FIG. 14, facilitates the creation of a composite image that excludes images of mirror edges lying between portions of the fields of view of individual cameras. From the geometry that has been described, it is apparent that the mirror edges lie within, or are encompassed by, the blind regions of the composite field of view corresponding to the composite image. It is also apparent that the narrow planar shaped blind regions lie between portions of adjacent individual fields of view that extend outwardly in substantially similar directions, and that these blind regions do not expand in size with increasing distance from the viewing system. Such expansion of the blind regions would be undesirable because it would allow them to envelope objects that are increasingly large with increasing distance from the viewing system. As described earlier in reference to FIG. 7, the individual images, and the composite image, are stored as data in memory  172 . Accordingly, eliminating portions of the individual fields of view corresponding to the blind regions of the composite field of view, as described above with reference to FIG. 14, results in a collection of stored data in memory  172  that excludes data representing images of mirror edges that lie within the blind regions, and it will be immediately apparent to those skilled in the art that the described exclusion of images of mirror edges from useful camera images may be accomplished by disregarding in memory  172 , or discarding from this memory, image data that corresponds to portions of the fields of view of the cameras that contain these mirror edges.  
         [0051]    [0051]FIG. 15 illustrates the pyramid of FIG. 14 with shades  560 ,  562 ,  564  and  566  positioned in planar regions  524 ,  526 ,  528 , and  530 , respectively. The shades reduce the amount of unwanted light that enters the cameras. Similar shades may be placed in blind regions between device  400 &#39;s field of view and one or more of the other image processing devices&#39; field of view. For example, if we recall that moving image device  400  in the direction of arrow  410  removes base edges  420  from the device&#39;s field of view, a shade may be placed in one or more of the planar blind regions that extend out from a base edge  420 .