Abstract:
A telepresence method and system for providing users the ability to navigate through an array of cameras capturing an environment. The array of cameras includes one or more series of cameras, wherein each series of cameras defines a path through the environment and wherein the cameras in each series have a progressively different perspective of the environment. Users interactively navigate through series of cameras, thereby simulating movement along paths.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. Non-Provisional Application claims the benefit of U.S. Provisional Application Serial No. 60/080,413, filed on Apr. 2, 1998, herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a telepresence system and, more particularly, to a navigable camera array telepresence system and method of using same. 
     2. Description of Related Art 
     In general, a need exists for the development of telepresence systems suitable for use with static venues, such as museums, and dynamic venues or events, such as a music concerts. The viewing of such venues is limited by time, geographical location, and the viewer capacity of the venue. For example, potential visitors to a museum may be prevented from viewing an exhibit due to the limited hours the museum is open. Similarly, music concert producers must turn back fans due to the limited seating of an arena. In short, limited access to venues reduces the revenue generated. 
     In an attempt to increase the revenue stream from both static and dynamic venues, such venues have been recorded for broadcast or distribution. In some instances, dynamic venues are also broadcast live. While such broadcasting increases access to the venues, it involves considerable production effort. Typically, recorded broadcasts must be cut and edited, as views from multiple cameras are pieced together. These editorial and production efforts are costly. 
     In some instances, the broadcast resulting from these editorial and production efforts provides viewers with limited enjoyment. Specifically, the broadcast is typically based on filming the venue from a finite number of predetermined cameras. Thus, the broadcast contains limited viewing angles and perspectives of the venue. Moreover, the viewing angles and perspectives presented in the broadcast are those selected by a producer or director during the editorial and production process; there is no viewer autonomy. Furthermore, although the broadcast is often recorded for multiple viewings, the broadcast has limited content life because each viewing is identical to the first. Because each showing looks and sounds the same, viewers rarely come back for multiple viewings. 
     A viewer fortunate enough to attend a venue in person will encounter many of the same problems. For example, a museum-goer must remain behind the barricades, viewing exhibits from limited angles and perspectives. Similarly, concert-goers are often restricted to a particular seat or section in an arena. Even if a viewer were allowed free access to the entire arena to videotape the venue, such a recording would also have limited content life because each viewing would be the same as the first. Therefore, a need exists for a telepresence system that preferably provides user autonomy while resulting in recordings with enhanced content life at a reduced production cost. 
     Apparently, attempts have been made to develop telepresence systems to satisfy some of the foregoing needs. One telepresence system is described in U.S. Pat. No. 5,708,469 for Multiple View Telepresence Camera Systems Using A Wire Cage Which Surrounds A Polarity Of Multiple Cameras And Identifies The Fields Of View, issued Jan. 13, 1998. The system disclosed therein includes a plurality of cameras, wherein each camera has a field of view that is space-contiguous with and at a right angle to at least one other camera. In other words, it is preferable that the camera fields of view do not overlap each other. A user interface allows the user to jump between views. In order for the user&#39;s view to move through the venue or environment, a moving vehicle carries the cameras. 
     This system, however, has several drawbacks. For example, in order for a viewer&#39;s perspective to move through the venue, the moving vehicle must be actuated and controlled. In this regard, operation of the system is complicated. Furthermore, because the camera views are contiguous, typically at right angles, changing camera views results in a discontinuous image. 
     Other attempts at providing a telepresence system have taken the form of a 360 degree camera systems. One such system is described in U.S. Pat. No. 5,745,305 for Panoramic Viewing Apparatus, issued Apr. 28 1998. The system described therein provides a 360 degree view of environment by arranging multiple cameras around a pyramid shaped reflective element. Each camera, all of which share a common virtual optical center, receives an image from a different side of the reflective pyramid. Other types of 360 degree camera systems employ a parabolic lens or a rotating camera. 
     Such 360 degree camera systems also suffer from drawbacks. In particular, such systems limit the user&#39;s view to 360 degrees from a given point perspective. In other words, 360 degree camera systems provide the user with a panoramic view from a single location. Only if the camera system was mounted on a moving vehicle could the user experience simulated movement through an environment. 
     U.S. Pat. No. 5,187,571 for Television System For Displaying Multiple Views of A Remote Location issued Feb. 16, 1993, describes a camera system similar to the 360 degree camera systems described above. The system described provides a user to select an arbitrary and continuously variable section of an aggregate field of view. Multiple cameras are aligned so that each camera&#39;s field of view merges contiguously with those of adjacent cameras thereby creating the aggregate field of view. The aggregate field of view may expand to cover 360 degrees. In order to create the aggregate field of view, the cameras&#39; views must be contiguous. In order for the camera views to be contiguous, the cameras have to share a common point perspective, or vertex. Thus, like the previously described 360 degree camera systems, the system of U.S. Pat. No. 5,187,571 limits a user&#39;s view to a single point perspective, rather than allowing a user to experience movement in perspective through an environment. 
     Also, with regard to the system of U.S. Pat. No. 5,187,571, in order to achieve the contiguity between camera views, a relatively complex arrangement of mirrors is required. Additionally, each camera seemingly must also be placed in the same vertical plane. 
     Thus, a need still exists for an improved telepresence system that provides the ability to better simulate a viewer&#39;s actual presence in a venue, preferably in real time. 
     SUMMARY OF THE INVENTION 
     These and other needs are satisfied by the present invention. A telepresence system according to one embodiment of the present invention includes an array of cameras, each of which has an associated view of an environment and an associated output representing the view. The system also includes a first user interface device having first user inputs associated with movement along a first path in the array. The system further includes a second user interface device having second user inputs associated with movement along a second path in the array. A processing element is coupled to the user interface devices. The processing the element receives and interprets the first inputs and selects outputs of cameras in the first path. Similarly, the processing element receives and interprets the second inputs and selects outputs of cameras in the second path independently of the first inputs. Thus, a first user and a second user are able to navigate simultaneously and independently through the array. In another embodiment of the present invention the telepresence system distinguishes between permissible cameras in the array and impermissible cameras in the array. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an overall schematic of one embodiment of the present invention. 
     FIG. 2 a  is a perspective view of a camera and a camera rail section of the array according to one embodiment of the present invention. 
     FIGS. 2 b - 2   d  are side plan views of a camera and a camera rail according to one embodiment of the present invention. 
     FIG. 2 e  is a top plan view of a camera rail according to one embodiment of the present invention. 
     FIG. 3 is a perspective view of a portion of the camera array according to one embodiment of the present invention. 
     FIG. 4 is a perspective view of a portion of the camera array according to an alternate embodiment of the present invention. 
     FIG. 5 is a flowchart illustrating the general operation of the user interface according to one embodiment of the present invention. 
     FIG. 6 is a flowchart illustrating in detail a portion of the operation shown in FIG.  5 . 
     FIG. 7 a  is a perspective view of a portion of one embodiment of the present invention illustrating the arrangement of the camera array relative to objects being viewed. 
     FIGS. 7 b - 7   g  illustrate views from the perspectives of selected cameras of the array in FIG. 7 a.    
     FIG. 8 is a schematic view of an alternate embodiment of the present invention. 
     FIG. 9 is a schematic view of a server according to one embodiment of the present invention. 
     FIG. 10 is a schematic view of a server according to an alternate embodiment of the present invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     1. General Description of Preferred Embodiments 
     The present invention relates to a telepresence system that, in preferred embodiments, uses modular, interlocking arrays of microcameras. The cameras are on rails, with each rail holding a plurality of cameras. These cameras, each locked in a fixed relation to every adjacent camera on the array and dispersed dimensionally in a given environment, enable remote viewers to navigate through such environment with the same spatial and visual cues (the changing perspective lines, the moving light reflections and shadows) that characterize an actual in-environment transit. 
     In another preferred embodiment, the outputs of these microcameras are linked by tiny (less than half the width of a human hair) Vertical Cavity Surface Emitting Lasers (VCSELs) to optical fibers, fed through area net hubs, buffered on server arrays or server farms (either for recording or (instantaneous) relay) and sent to viewers at remote terminals, interactive wall screens, or mobile image appliances (like Virtual Retinal Displays). Each remote viewer, through an intuitive graphical user interface (GUI), can navigate effortlessly through the environment, enabling seamless movement through the event. 
     This involves a multiplexed, electronic switching process (invisible to the viewer) which moves the viewer&#39;s point perspective from camera to camera. Rather than relying, per se, on physically moving a microcamera through space, the system uses the multiplicity of positioned microcameras to move the viewer&#39;s perspective from microcamera node to adjacent microcamera node in a way that provides the viewer with a sequential visual and acoustical path throughout the extent of the array. This allows the viewer to fluidly track or dolly through a 3-dimensional remote environment, to move through an event and make autonomous real-time decisions about where to move and when to linger. 
     Instead of investing the viewer with the capacity to physically move a robotic camera, which would immediately limit the number of viewers that could simultaneously control their own course and navigate via a given camera, the System allows the viewer to float between a multiplicity of microcamera outputs in a way that, via electronic switching (and thus movement through the array), merges their fields of view into a seamless motion path. 
     2. Detailed Description of Preferred Embodiments 
     Certain embodiments of the present invention will now be described in greater detail with reference to the drawings. It is understood that the operation and functionality of many of the components of the embodiments described herein are known to one skilled in the art and, as such, the present description does not go into detail into such operative and functionality. 
     A telepresence system  100  according to the present invention is shown in FIG.  1 . The telepresence system  100  generally includes an array  10  of cameras  14  coupled to a server  18 , which in turn is coupled to one or more users  22  each having a user interfaced/display device  24 . As will be understood to one skilled it the art, the operation and functionality of the embodiment described herein is provided, in part, by the server and user interface/display device. While the operation of these components is not described by way of particular code listings or logic diagrams, it is to be understood that one skilled in the art will be able to arrive at suitable implementations based on the functional and operational details provided herein. Furthermore, the scope of the present invention is not to be construed as limited to any particular code or logic implementation. 
     In the present embodiment, the camera array  10  is conceptualized as being in an X, Z coordinate system. This allows each camera to have an associated, unique node address comprising an X, and Z coordinate (X, Z). In the present embodiment, for example, a coordinate value corresponding to an axis of a particular camera represents the number of camera positions along that axis the particular camera is displaced from a reference camera. In the present embodiment, from the user&#39;s perspective the X axis runs left and right, and the Z axis runs down and up. Each camera  14  is identified by its X, Z coordinate. It is to be understood, however, that other methods of identifying cameras  14  can be used. For example, other coordinate systems, such as those noting angular displacement from a fixed reference point as well as coordinate systems that indicate relative displacement from the current camera node may be used. In another alternate embodiment, the array is three dimensional, located in an X, Y, Z coordinate system. 
     The array  10  comprises a plurality of rails  12 , each rail  12  including a series of cameras  14 . In the present preferred embodiment, the cameras  14  are microcameras. The output from the microcameras  14  are coupled to the server  18  by means of local area hubs  16 . The local area hubs  16  gather the outputs and, when necessary, amplify the outputs for transmission to the server  18 . In an alternate embodiment, the local area hubs  16  multiplex the outputs for transmission to the server  18 . Although the figure depicts the communication links  15  between the cameras  14  and the server  18  as being hardwired, it is to be understood that wireless links may be employed. Thus, it is within the scope of the present invention for the communication links  15  to take the form of fiber optics, cable, satellite, microwave transmission, internet, and the like. 
     Also coupled to the server  18  is an electronic storage device  20 . The server  18  transfers the outputs to the electronic storage device  20 . The electronic (mass) storage device  20 , in turn, transfers each camera&#39;s output onto a storage medium or means, such as CD-ROM, DVD, tape, platter, disk array, or the like. The output of each camera  14  is stored in a particular location on the storage medium associated with that camera  14  or is stored with an indication to which camera  14  each stored output corresponds. For example, the output of each camera  14  is stored in contiguous locations on a separate disk, tape, CD-ROM, or platter. As is known in the art, the camera output may be stored in a compressed format, such as JPEG, MPEG 1 , MPEG 2 , and the like. Having stored each output allows a user to later view the environment over and over again, each time moving through the array  10  in a new path, as described below. In some embodiments of the present invention, such as those providing only real-time viewing, no storage device is required. 
     As will be described in detail below, the server  18  receives output from the cameras  14  in the array. The server  18  processes these outputs for either storage in the electronic storage device  20 , transmission to the users  22  or both. 
     It is to be understood that although the server  18  is configured to provide the functionality of the system  100  in the present embodiment, it is to be understood that other processing elements may provide the functionality of the system  100 . For example, in alternate embodiments, the user interface device is a personal computer programmed to interpret the user input and transmit an indication of the desired current node address, buffer outputs from the array, and provide other of the described functions. 
     As shown, the system  100  can accommodate (but does not require) multiple users  22 . Each user  22  has associated therewith a user interface device including a user display device (collectively  24 ). For example, user  22 - 1  has an associated user interface device and a user display device in the form of a computer  24 - 1  having a monitor and a keyboard. User  22 - 2  has associated therewith an interactive wall screen  24 - 2  which serves as a user interface device and a user display device. The user interface device and the user display device of user  22 - 3  includes a mobile audio and image appliance  24 - 3 . A digital interactive TV  24 - 4  is the user interface device and user display device of user  22 - 4 . Similarly, user  22 - 5  has a voice recognition unit and monitor  24 - 5  as the user interface and display devices. It is to be understood that the foregoing user interface devices and user display devices are merely exemplary; for example, other interface devices include a mouse, touch screen, biofeedback devices, as well as those identified in U.S. Provisional Patent Application Serial No. 60/080,413 and the like. 
     As described in detail below, each user interface device  24  has associated therewith user inputs. These user inputs allow each user  22  to move or navigate independently through the array  10 . In other words, each user  22  enters inputs to generally select which camera outputs are transferred to the user display device. Preferably, each user display device includes a graphical representation of the array  10 . The graphical representation includes an indication of which camera in the array the output of which is being viewed. The user inputs allow each user to not only select particular cameras, but also to select relative movement or navigational paths through the array  10 . 
     As shown in FIG. 1, each user  22  may be coupled to the server  18  by an independent communication link. Furthermore, each communication link may employ different technology. For example, in alternate embodiments, the communication links include an internet link, a microwave signal link, a satellite link, a cable link, a fiber optic link, a wireless link, and the like. 
     It is to be understood that the array  10  provides several advantages. For example, because the array  10  employs a series of cameras  14 , no individual camera, or the entire array  10  for that matter, need be moved in order to obtain a seamless view of the environment. Instead, the user navigates through the array  10 , which is strategically placed through and around the physical environment to be viewed. Furthermore, because the cameras  14  of the array  10  are physically located at different points in the environment to be viewed, a user is able to view changes in perspective, a feature unavailable to a single camera that merely changes focal length. 
     Microcameras 
     Each camera  14  is preferably a microcamera. The microcameras—microlenses mounted on thumbnail-sized CMOS active pixel sensor (APS) microchips—are arranged in patterns that enable viewers to move radically, in straight lines, or in fluid combinations thereof. The cameras are produced in a mainstream manufacturing process, by several companies, including Photobit, Pasadena, Calif.; Sarnoff Corporation, Princeton, N.J.; and VLSI Vision, Ltd., Edinburgh, Scotland. 
     Structure of the Array 
     The structure of the array  10  will now be described in greater detail with reference to FIGS. 2 a - 2   e . In general, the camera array  10  of the present embodiment comprises a series of modular rails  12  carrying microcameras  14 . The structure of the rails  12  and cameras  14  will now be discussed in greater detail with reference to FIGS. 2 a  through  2   d . Each camera  14  includes registration pins  34 . In the preferred embodiment, the cameras  14  utilize VCSELs to transfer their outputs to the rail  12 . It is to be understood that the present invention is not limited to any particular type of camera  14 , however, or even to an array  10  consisting of only one type of camera  14 . 
     Each rail  12  includes two sides,  12   a ,  12   b , at least one of which  12   b  is hingeably connected to the base  12   c  of the rail  12 . The base  12   c  includes docking ports  36  for receiving the registration pins  34  of the camera  14 . When the camera  14  is seated on a rail  12  such that the registration pins  34  are fully engaged in the docking ports  36 , the hinged side  12   b  of the rail  12  is moved against the base  32  of the camera  14 , thereby securing the camera  14  to the rail  12 . 
     Each rail  12  further includes a first end  38  and a second end  44 . The first end  38  includes, in the present embodiment, two locking pins  40  and a protected transmission relay port  42  for transmitting the camera outputs. The second end  44  includes two guide holes  46  for receiving the locking pins  40 , and a transmission receiving port  48 . Thus, the first end  38  of one rail  12  is engagable with a second end  44  of another rail  12 . Therefore, each rail  12  is modular and can be functionally connected to another rail to create the array  10 . 
     Once the camera  14  is securely seated to the rail  12 , the camera  14  is positioned such that the camera output may be transmitted via the VCSEL to the rail  12 . Each rail  12  includes communication paths for transmitting the output from each camera  14 . 
     Although the array  10  is shown having a particular configuration, it is to be understood that virtually any configuration of rails  12  and cameras  14  is within the scope of the present invention. For example, the array  10  may be a linear array of cameras  14 , a 2-dimensional array of cameras  14 , a 3-dimensional array of cameras  14 , or any combination thereof. Furthermore, the array  10  need not be comprised solely of linear segments, but rather may include curvilinear sections. 
     The array  10  is supported by any of a number of support means. For example, the array  10  can be fixedly mounted to a wall or ceiling; the array  10  can be secured to a moveable frame that can be wheeled into position in the environment or supported from cables. 
     FIG. 3 illustrates an example of a portion of the array  10 . As shown, the array  10  comprises five rows of rails  12   a , through  12   e . Each of these rails  12   a - 12   e  is directed towards a central plane, which substantially passes through the center row  12   c . Consequently, for any object placed in the same plane as the middle row  12   c , a user would be able to view the object essentially from the bottom, front, and top. 
     As noted above, the rails  12  of the array  10  need not have the same geometry. For example, some of the rails  12  may be straight while others may be curved. For example, FIG. 4 illustrates the camera alignment that results from utilizing curved rails. It should be noted that rails in FIG. 4 have been made transparent so that the arrangement of cameras  14  may be easily seen. 
     In an alternate embodiment, each rail is configured in a step-like fashion with each camera above and in front of a previous camera. In such an arrangement, the user has the option of moving forward through the environment. 
     It is to be understood that the spacing of the microcameras  14  depends on the particular application, including the objects being viewed, the focal length of the microcameras  14 , and the speed of movement through the array  10 . In one embodiment the distance between microcameras  14  can be approximated by analogy to a conventional movie reel recording projector. In general, the speed of movement of a projector through an environment divided by the frames per unit of time second results in a frame-distance ratio. 
     For example, as shown by the following equations, in some applications a frame is taken ever inch. A conventional movie projector records twenty-four frames per second. When such a projector is moved through an environment at two feet per second, a frame is taken approximately every inch.              2                 ft     sec     ÷       24                 frames     sec       =                    2                 ft       24                 frames       =                    1                 ft       12                 frames       =                     
          12                 inches         12                 frames       =         1                 inch       1                 frame       =     1                 frame                 per                   inch   .                                          
     A frame of the projector is analogous to a camera  14  in the present invention. Thus, where one frame per inch results in a movie having a seamless view of the environment, so too does one camera  14  per inch. Thus, in one embodiment of the present invention the cameras  14  are spaced approximately one inch apart, thereby resulting in a seamless view of the environment. 
     Navigation Through the System 
     The general operation of the present embodiment will now be described with reference to FIG.  5  and continuing reference to FIG.  1 . As shown in step  110 , the user is presented with a predetermined starting view of the environment corresponding to a starting camera. It is to be understood that the operation of the system is controlled, in part, by software residing in the server. As noted above, the system associates each camera in the array with a coordinate. Thus, the system is able to note the coordinates of the starting camera node. The camera output and, thus the corresponding view, changes only upon receiving a user input. 
     When the user determines that they want to move or navigate through the array, the user enters a user input through the user interface device  24 . As described below, the user inputs of the present embodiment generally include moving to the right, to the left, up, or down in the array. Additionally, a user may jump to a particular camera in the array. In alternate embodiments, a subset of these or other inputs, such as forward, backward, diagonal, over, and under, are used. The user interface device, in turn, transmits the user input to the server in step  120 . 
     Next, the server receives the user input in step  130  and proceeds to decode the input. In the present embodiment, decoding the input generally involves determining whether the user wishes to move to the right, to the left, up, or down in the array. 
     On the other hand, if the received user input does not correspond to backward, then The server  18  proceeds to determine whether the input corresponds to moving to the user&#39;s right in the array  10 . This determination is shown in step  140 . If the received user input does correspond to moving to the right, the current node address is incremented along the X axis in step  150  to obtain an updated address. 
     If the received user input does not correspond to moving to the right in the array, the server  18  then determines whether the input corresponds to moving to the user&#39;s left in the array  10  in step  160 . Upon determining that the input does correspond to moving to the left, the server  18  then decrements the current node address along the X axis to arrive at the updated address. This is shown in step  170 . 
     If the received user input does not correspond to either moving to the right or to the left, the server  18  then determines whether the input corresponds to moving up in the array. This determination is made in step  180 . If the user input corresponds to moving up, in step  190 , the server  18  increments the current node address along the Z axis, thereby obtaining an updated address. 
     Next, the server  18  determines whether the received user input corresponds to moving down in the array  10 . This determination is made in step  200 . If the input does correspond to moving down in the array  10 , in step  210  the server  18  decrements the current node address along the Z axis. 
     Lastly, in step  220  the server  18  determines whether the received user input corresponds to jumping or changing the view to a particular camera  14 . As indicated in FIG. 5, if the input corresponds to jumping to a particular camera  14 , the server  18  changes the current node address to reflect the desired camera position. Updating the node address is shown as step  230 . In an alternate embodiment, the input corresponds to jumping to a particular position in the array  10 , not identified by the user as being a particular camera but by some reference to the venue, such as stage right. 
     It is to be understood that the server  18  may decode the received user inputs in any of a number of ways, including in any order. For example, in an alternate embodiment the server  18  first determines whether the user input corresponds to up or down. In another alternate, preferred embodiment, user navigation includes moving forward, backward, to the left and right, and up and down through a three dimensional array. 
     If the received user input does not correspond to any of the recognized inputs, namely to the right, to the left, up, down, or jumping to a particular position in the array  10  then in step  240 , the server  18  causes a message signal to be transmitted to the user display device  24 , causing a message to be displayed to the user  22  that the received input was not understood. Operation of the system  100  then continues with step  120 , and the server  18  awaits receipt of the next user input. 
     After adjusting the current node address, either by incrementing or decrementing the node address along an axis or by jumping to a particular node address, the server  18  proceeds in step  250  to adjust the user&#39;s view. Once the view is adjusted, operation of the system  100  continues again with step  120  as the server  18  awaits receipt of the next user input. 
     In an alternate embodiment, the server  18  continues to update the node address and adjust the view based on the received user input. For example, if the user input corresponded to “moving to the right”, then operation of the system  100  would continuously loop through steps  140 ,  150 , and  250 , checking for a different input. When the different input is received, the server  18  continuously updates the view accordingly. 
     It is to be understood that the foregoing user inputs, namely, to the right, to the left, up, and down, are merely general descriptions of movement through the array. Although the present invention is not so limited, in the present preferred embodiment, movement in each of these general directions is further defined based upon the user input. 
     Accordingly, FIG. 6 is a more detailed diagram of the operation of the system according to steps  140 ,  150 , and  250  of FIG.  5 . Moreover, it is to be understood that while FIG. 6 describes more detailed movement one direction i.e., to the right, the same detailed movement can be applied in any other direction. As illustrated, the determination of whether the user input corresponds to moving to the right actually involves several determinations. As described in detail below, these determinations include moving to the right through the array  10  at different speeds, moving to the right into a composited additional source output at different speeds, and having the user input overridden by the system  100 . 
     The present invention allows a user  22  to navigate through he array  10  at the different speeds. Depending on the speed (i.e. number of camera nodes transversed per unit of time) indicated by the user&#39;s input, such as movement of a pointing device (or other interface device), the server  18  will apply an algorithm that controls the transition between camera outputs either at critical speed (n nodes/per unit of time), under critical speed (n−1 nodes/per unit of time), or over critical speed (n+1 nodes/per unit of time). 
     It is to be understood that speed of movement through the array  10  can alternatively be expressed as the time to switch from one camera  14  to another camera  14 . 
     Specifically, as shown in step  140   a , the server  18  makes the determination whether the user input corresponds to moving to the right at a critical speed. The critical speed is preferably a predetermined speed of movement through the array  10  set by the system operator or designer depending on the anticipated environment being viewed. Further, the critical speed depends upon various other factors, such as focal length, distance between cameras, distance between the cameras and the viewed object, and the like. The speed of movement through the array  10  is controlled by the number of cameras  14  traversed in a given time period. Thus, the movement through the array  10  at critical speed corresponds to traversing some number, “n”, camera nodes per millisecond, or taking some amount of time, “s”, to switch from one camera  14  to another. It is to be understood that in the same embodiment the critical speed of moving through the array  10  in one dimension need not equal the critical speed of moving through the array in another dimension. Consequently, the server  18  increments the current node address along the X axis at n nodes per millisecond. 
     In the present preferred embodiment the user traverses twenty-four cameras  14  per second. As discussed above, a movie projector records twenty-four frames per second. Analogizing between the movie projector and the present invention, at critical the user traverses (and the server  18  switches between) approximately twenty-four cameras  14  per second, or a camera  14  approximately every 0.04167 seconds. 
     As shown in FIG. 6, the user  22  may advance not only at critical speed, but also at over the critical speed, as shown in step  140   b , or at under the critical speed, as shown in step  140   c . Where the user input “I” indicates movement through the array  10  at over the critical speed, the server  18  increments the current node address along the X axis by a unit of greater than n, for example, at n+2 nodes per millisecond. The step of incrementing the current node address at n+1 nodes per millisecond along the X axis is shown in step  150   b . Where the user input “I” indicates movement through the array  10  at under the critical speed, the server  18  proceeds to increment the current node address at a variable less than n, for example, at n−1 nodes per millisecond. This operation is shown as step  150   c.    
     Scaleable Arrays 
     The shape of the array  10  can also be electronically scaled and the system  100  designed with a “center of gravity” that will ease a user&#39;s image path back to a “starting” or “critical position” node or ring of nodes, either when the user  22  releases control or when the system  100  is programmed to override the user&#39;s autonomy; that is to say, the active perimeter or geometry of the array  10  can be pre-configured to change at specified times or intervals in order to corral or focus attention in a situation that requires dramatic shaping. The system operator can, by real-time manipulation or via a pre-configured electronic proxy sequentially activate or deactivate designated portions of the camera array  10 . This is of particular importance in maintaining authorship and dramatic pacing in theatrical or entertainment venues, and also for implementing controls over how much freedom a user  22  will have to navigate through the array  10 . 
     In the present embodiment, the system  100  can be programmed such that certain portions of the array  10  are unavailable to the user  22  at specified times or intervals. Thus, continuing with step  140   d  of FIG. 6, the server  18  makes the determination whether the user input corresponds to movement to the right through the array but is subject to a navigation control algorithm. The navigation control algorithm causes the server  18  to determine, based upon navigation control factors, whether the user&#39;s desired movement is permissible. 
     More specifically, the navigation control algorithm, which is programmed in the server  18 , determines whether the desired movement would cause the current node address to fall outside the permissible range of node coordinates. In the present embodiment, the permissible range of node coordinates is predetermined and depends upon the time of day, as noted by the server  18 . Thus, in the present embodiment, the navigation control factors include time. As will be appreciated by those skilled in the art, permissible camera nodes and control factors can be correlated in a table stored in memory. 
     In an alternate embodiment, the navigation control factors include time as measured from the beginning of a performance being viewed, also as noted by the server. In such an embodiment, the system operator can dictate from where in the array a user will view certain scenes. In another alternate embodiment, the navigation control factor is speed of movement through the array. For example, the faster a user  22  moves or navigates through the array, the wider the turns must be. In other alternate embodiments, the permissible range of node coordinates is not predetermined. In one embodiment, the navigation control factors and, therefore, the permissible range, is dynamically controlled by the system operator who communicates with the server via an input device. 
     Having determined that the user input is subject to the navigation control algorithm, the server  18  further proceeds, in step  150   d , to increment the current node address along a predetermined path. By incrementing the current node address along a predetermined path, the system operator is able to corral or focus the attention of the user  22  to the particular view of the permissible cameras  14 , thereby maintaining authorship and dramatic pacing in theatrical and entertainment venues. 
     In an alternate embodiment where the user input is subject to a navigation control algorithm, the server  18  does not move the user along a predetermined path. Instead, the server  18  merely awaits a permissible user input and holds the view at the current node. Only when the server  18  receives a user input resulting in a permissible node coordinate will the server  18  adjust the user&#39;s view. 
     Additional Source Output 
     In addition to moving through the array  10 , the user  22  may, at predetermined locations in the array  10 , choose to leave the real world environment being viewed. More specifically, additional source outputs, such as computer graphic imagery, virtual world imagery, applets, film clips, and other artificial and real camera outputs, are made available to the user  22 . In one embodiment, the additional source output is composited with the view of the real environment. In an alternate embodiment, the user&#39;s view transfers completely from the real environment to that offered by the additional source output. 
     More specifically, the additional source output is stored (preferably in digital form) in the electronic storage device  20 . Upon the user  22  inputting a desire to view the additional source output, the server  18  transmits the additional source output to the user interface/display device  24 . The present embodiment, the server  18  simply transmits the additional source output to the user display device  24 . In an alternate embodiment, the server  18  first composites the additional source output with the camera output and then transmits the composited signal to the user interface/display device  24 . 
     As shown in step  140   e , the server  18  makes the determination whether the user input corresponds to moving in the array into the source output. If the user  22  decides to move into the additional source output, the server  18  adjusts the view by substituting the additional source output for the updated camera output identified in either of steps  150   a-d.    
     Once the current node address is updated in either of steps  150   a-d , the server  18  proceeds to adjust the user&#39;s view in step  250 . When adjusting the view, the server  18  “mixes” the existing or current camera output being displayed with the output of the camera  14  identified by the updated camera node address. Mixing the outputs is achieved differently in alternate embodiments of the invention. In the present embodiment, mixing the outputs involves electronically switching at a particular speed from the existing camera output to the output of the camera  14  having the new current node address. 
     It is to be understood that in this and other preferred embodiments disclosed herein, the camera outputs are synchronized. As is well known in the art, a synchronizing signal from a “sync generator” is supplied to the cameras. The sync generator may take the form of those used in video editing and may comprise, in alternate embodiments, part of the server, the hub, and/or a separate component coupled to the array. 
     As described above, at critical speed, the server  18  switches camera outputs approximately at a rate of 24 per second, or one every 0.04167 seconds. If the user  22  is moving through the array  10  at under the critical speed, the outputs of the intermediate cameras  14  are each displayed for a relatively longer duration than if the user is moving at the critical speed. Similarly, each output is displayed for a relatively shorter duration when a user navigates at over the critical speed. In other words, the server  18  adjusts the switching speed based on the speed of the movement through the array  10 . 
     Of course, it is to be understood that in a simplified embodiment of the present invention, the user may navigate at only the critical speed. 
     In another alternate embodiment, mixing the outputs is achieved by compositing the existing or current output and the updated camera node output. In yet another embodiment, mixing involves dissolving the existing view into the new view. In still another alternate embodiment, mixing the outputs includes adjusting the frame refresh rate of the user display device. Additionally, based on speed of movement through the array, the server may add motion blur to convey the realistic sense of speed. 
     In yet another alternate embodiment, the server causes a black screen to be viewed instantaneously between camera views. Such an embodiment is analogous to blank film between frames in a movie reel. Furthermore, although not always advantageous, such black screens reduce the physiologic “carrying over” of one view into a subsequent view. 
     It is to be understood that the user inputs corresponding to movements through the array at different speeds may include either different keystrokes on a keypad, different positions of a joystick, positioning a joystick in a given position for a predetermined length of time, and the like. Similarly, the decision to move into an additional source output may be indicated by a particular keystroke, joystick movement, or the like. 
     In an alternate embodiment, although not always necessary, to ensure a seamless progression of views, the server  18  also transmits to the user display device  24  outputs from some or all of the intermediate cameras, namely those located between the current camera node and the updated camera node. Such an embodiment will now be described with reference to FIGS. 7 a - 7   g . Specifically, FIG. 7 a  illustrates a curvilinear portion of an array  10  that extends along the X axis or to the left and right from the user&#39;s perspective. Thus, the coordinates that the server  18  associates with the cameras  14  differ only in the X coordinate. More specifically, for purposes of the present example, the cameras  14  can be considered sequentially numbered, starting with the left-most camera  14  being the first, i.e., number “1”. The X coordinate of each camera  14  is equal to the camera&#39;s position in the array. For illustrative purposes, particular cameras will be designate  14 -X, where X equals the camera&#39;s position in the array  10  and, thus, its associated X coordinate. 
     In general, FIGS. 7 a - 7   g  illustrate possible user movement through the array  10 . The environment to be viewed includes three objects  602 ,  604 ,  606 , the first and second of which include numbered surfaces. As will be apparent, these numbered surface allow a better appreciation of the change in user perspective. 
     In FIG. 7 a , six cameras  14 - 2 ,  14 - 7 ,  14 - 11 ,  14 - 14 ,  14 - 20 ,  14 - 23  of the array  10  are specifically identified. The boundaries of each camera&#39;s view is identified by the pair of lines  14 - 2   a ,  14 - 7   a ,  14 - 11   a ,  14 - 14   a ,  14 - 20   a ,  14 - 23   a , radiating from each identified camera  14 - 2 ,  14 - 7 ,  14 - 11 ,  14 - 14 ,  14 - 20 ,  14 - 23 , respectively. As described below, in the present example the user  22  navigates through the array  10  along the X axis such that the images or views of the environment are those corresponding to the identified cameras  14 - 2 ,  14 - 7 ,  14 - 11 ,  14 - 14 ,  14 - 20 ,  14 - 23 . 
     The present example provides the user  22  with the starting view from camera  14 - 2 . This view is illustrated in FIG. 7 b . The user  22 , desiring to have a better view of the object  702 , pushes the “7” key on the keyboard. This user input is transmitted to and interpreted by the server  18 . 
     Because the server  18  has been programmed to recognized the “7” key as corresponding to moving or jumping through the array to camera  14 - 7 . The server  18  changes the X coordinate of the current camera node address to  7 , selects the output of camera  14 - 7 , and adjusts the view or image sent to the user  22 . Adjusting the view, as discussed above, involves mixing the outputs of the current and updated camera nodes. Mixing the outputs, in turn, involves switching intermediate camera outputs into the view to achieve the seamless progression of the discrete views of cameras  14 - 2  through  14 - 7 , which gives the user  22  the look and feel of moving around the viewed object. The user  22  now has another view of the first object  702 . The view from camera  14 - 7  is shown in FIG. 7 c . As noted above, if the jump in camera nodes is greater than a predetermined limit, the server  18  would omit some or all of the intermediate outputs. 
     Pressing the “right arrow” key on the keyboard, the user  22  indicates to the system  100  a desire to navigate to the right at critical speed. The server  18  receives and interprets this user input as indicating such and increments the current camera node address by n=4. Consequently, the updated camera node address is  14 - 11 . The server  18  causes the mixing of the output of camera  14 - 11  with that of camera  14 - 7 . Again, this includes switching into the view the outputs of the intermediate cameras (i.e.,  14 - 8 ,  14 - 9 , and  14 - 10 ) to give the user  22  the look and feel of navigating around the viewed object. The user  22  is thus presented with the view from camera  14 - 11 , as shown in FIG. 7 d.    
     Still interested in the first object  702 , the user  22  enters a user input, for example, “alt-right arrow,” indicating a desire to move to the right at less than critical speed. Accordingly, the server  18  increments the updated camera node address by n−1 nodes, namely 3 in the present example, to camera  14 - 14 . The outputs from cameras  14 - 11  and  14 - 14  are mixed, and the user  22  is presented with a seamless view associated with cameras  14 - 11  through  14 - 14 . FIG. 7 e  illustrates the resulting view of camera  14 - 14 . 
     With little to see immediately after the first object  702 , the user  22  enters a user input such as “shift-right arrow,” indicating a desire to move quickly through the array  10 , i.e., at over the critical speed. The server  18  interprets the user input and increments the current node address by n+2, or 6 in the present example. The updated node address thus corresponds to camera  14 - 20 . The server  18  mixes the outputs of cameras  14 - 14  and  14 - 20 , which includes switching into the view the outputs of the intermediate cameras  14 - 15  through  14 - 19 . The resulting view of camera  14 - 20  is displayed to the user  22 . As shown in FIG. 7 f , the user  22  now views the second object  704 . 
     Becoming interested in the third object  704 , the user  22  desires to move slowly through the array  10 . Accordingly, the user  22  enters “alt-right arrow” to indicate moving to the right at below critical speed. Once the server  18  interprets the received user input, it updates the current camera node address along the X axis by 3 to camera  14 - 23 . The server  18  then mixes the outputs of camera  14 - 20  and  14 - 23 , thereby providing the user  22  with a seamless progression of views through camera  14 - 23 . The resulting view  14 - 23   a  is illustrated in FIG. 7 g.    
     Other Data Devices 
     It is to be understood that devices other than cameras may be interspersed in the array. These other devices, such as motion sensors and microphones, provide data to the server(s) for processing. For example, in alternate embodiments output from motion sensors or microphones are fed to the server(s) and used to scale the array. More specifically, permissible camera nodes (as defined in a table stored in memory) are those near the sensor or microphone having a desired output e.g., where there is motion or sound. As such, navigation control factors include output from other such devices. Alternatively, the output from the sensors or microphones are provided to the user. 
     An alternate embodiment in which the array of cameras includes multiple microphones interspersed among the viewed environment and the cameras will now be described with reference to FIG.  8 . The system  800  generally includes an array of cameras  802  coupled to a server  804 , which, in turn, is coupled to one or more user interface and display devices  806  and an electronic storage device  808 . A hub  810  collects and transfers the outputs from the array  802  to the server  804 . More specifically, the array  802  comprises modular rails  812  that are interconnected. Each rail  812  carries multiple microcameras  814  and a microphone  816  centrally located at rail  812 . Additionally, the system  800  includes microphones  818  that are physically separate from the array  802 . The outputs of both the cameras  814  and microphones  816 ,  818  are coupled to the server  804  for processing. 
     In general, operation of the system  800  proceeds as described with respect to system  100  of FIGS. 1-2 d  and  5 - 6 . Beyond the operation of the previously described system  100 , however, the server  804  receives the sound output from the microphones  816 ,  818  and, as with the camera output, selectively transmits sound output to the user. As the server  804  updates the current camera node address and changes the user&#39;s view, it also changes the sound output transmitted to the user. In the present embodiment, the server  804  has stored in memory an associated range of camera nodes with a given microphone, namely the cameras  814  on each rail  810  are associated with the microphone  816  on that particular rail  810 . In the event a user attempts to navigate beyond the end of the array  802 , the server  804  determines the camera navigation is impermissible and instead updates the microphone node output to that of the microphone  818  adjacent to the array  802 . 
     In an alternate embodiment, the server  804  might include a database in which camera nodes in a particular area are associated with a given microphones. For example, a rectangle defined by the (X, Y, Z) coordinates (0,0,0), (10,0,0), (10,5,0), (0,5,0), (0,0,5), (10,0,5), (10,5,5) and (0,5,5) are associated with a given microphone. It is to be understood that selecting one of the series of microphones based on the user&#39;s position (or view) in the array provides the user with a sound perspective of the environment that coincides with the visual perspective. 
     It is to be understood that the server of the embodiments discussed above may take any of a number of known configurations. Two examples of server configurations suitable for use with the present invention will be described with reference to FIGS. 9 and 10. Turning first to FIG. 9, the server  902 , electronic storage device  20 , array  10 , users ( 1 , 2 , 3 , . . . N)  22 - 1 - 22 -N, and associated user interface/display devices  24 - 1 - 24 -N are shown therein. 
     The server  902  includes, among other components, a processing means in the form of one or more central processing units (CPU)  904  coupled to associated read only memory (ROM)  906  and a random access memory (RAM)  908 . In general, ROM  906  is for storing the program that dictates the operation of the server  902 , and the RAM  908  is for storing variables and values used by the CPU  904  during operation. Also coupled to the CPU  904  are the user interface/display devices  24 . It is to be understood that the CPU may, in alternate embodiments, comprise several processing units, each performing a discrete function. 
     Coupled to both the CPU  904  and the electronic storage device  20  is a memory controller  910 . The memory controller  910 , under direction of the CPU  904 , controls accesses (reads and writes) to the storage device  20 . Although the memory controller  910  is shown as part of the server  902 , it is to be understood that it may reside in the storage device  20 . 
     During operation, the CPU  904  receives camera outputs from the array  10  via bus  912 . As described above, the CPU  904  mixes the camera outputs for display on the user interface/display device  24 . Which outputs are mixed depends on the view selected by each user  22 . Specifically, each user interface/display devices  24  transmits across bus  914  the user inputs that define the view to be displayed. Once the CPU  904  mixes the appropriate outputs, it transmits the resulting output to the user interface/display device  24  via bus  916 . As shown, in the present embodiment, each user  22  is independently coupled to the server  902 . 
     The bus  912  also carries the camera outputs to the storage device  20  for storage. When storing the camera outputs, the CPU  904  directs the memory controller  910  to store the output of each camera  14  in a particular location of memory in the storage device  20 . 
     When the image to be displayed has previously been stored in the storage device  20 , the CPU  904  causes the memory controller  910  to access the storage device  20  to retrieve the appropriate camera output. The output is thus transmitted to the CPU  904  via bus  918  where it is mixed. Bus  918  also carries additional source output to the CPU  904  for transmission to the users  22 . As with outputs received directly from the array  10 , the CPU  904  mixes these outputs and transmits the appropriate view to the user interface/display device  24 . 
     FIG. 10 shows a server configuration according to an alternate embodiment of the present invention. As shown therein, the server  1002  generally comprises a control central processing unit (CPU)  1004 , a mixing CPU  1006  associated with each user  22 , and a memory controller  1008 . The control CPU  1004  has associated ROM  1010  and RAM  1012 . Similarly, each mixing CPU  1006  has associated ROM  1014  and RAM  1016 . 
     To achieve the functionality described above, the camera outputs from the array  10  are coupled to each of the mixing CPUs  1  through N  1006 - 1 ,  1006 -N via bus  1018 . During operation, each user  22  enters inputs in the interface/display device  24  for transmission (via bus  1020 ) to the control CPU  1004 . The control CPU  1004  interprets the inputs and, via buses  1022 - 1 ,  1022 -N, transmits control signals to the mixing CPUs  1006 - 1 ,  1006 -N instructing them which camera outputs received on bus  1018  to mix. As the name implies, the mixing CPUs  1006 - 1 ,  1006 -N mix the outputs in order to generate the appropriate view and transmit the resulting view via buses  1024 - 1 ,  1024 -N to the user interface/display devices  24 - 1 ,  24 -N. 
     In an alternate related embodiment, each mixing CPU  1006  multiplexes outputs to more than one user  22 . Indications of which outputs are to mixed and transmitted to each user  22  comes from the control CPU  1004 . 
     The bus  1018  couples the camera outputs not only to the mixing CPUs  1006 - 1 ,  1006 -N, but also to the storage device  20 . Under control of the memory controller  1008 , which in turn is controlled by the control CPU  1004 , the storage device  20  stores the camera outputs in known storage locations. Where user inputs to the control CPU  1004  indicate a users&#39;  22  desire to view stored images, the control CPU  1004  causes the memory controller  1008  to retrieve the appropriate images from the storage device  20 . Such images are retrieved into the mixing CPUs  1006  via bus  1026 . Additional source output is also retrieved to the mixing CPUs  1006 - 1 ,  1006 -N via bus  1026 . The control CPU  1004  also passes control signals to the mixing CPUs  1006 - 1 ,  1006 -N to indicate which outputs are to be mixed and displayed. 
     Stereoscopic Views 
     It is to be understood that it is within the scope of the present invention to employ stereoscopic views of the environment. To achieve the stereoscopic view, the system retrieves from the array (or the electronic storage device) and simultaneously transmits to the user at least portions of outputs from two cameras. The server processing element mixes these camera outputs to achieve a stereoscopic output. Each view provided to the user is based on such a stereoscopic output. In one stereoscopic embodiment, the outputs from two adjacent cameras in the array are used to produce one stereoscopic view. Using the notation of FIGS. 7 a - 7   g , one view is the stereoscopic view from cameras  14 - 1  and  14 - 2 . The next view is based on the stereoscopic output of cameras  14 - 2  and  14 - 3  or two other cameras. Thus, in such an embodiment, the user is provided the added feature of a stereoscopic seamless view of the environment. 
     Multiple Users 
     As described above, the present invention allows multiple users to simultaneously navigate through the array independently of each other. To accommodate multiple users, the systems described above distinguish between inputs from the multiple users and selects a separate camera output appropriate to each user&#39;s inputs. In one such embodiment, the server tracks the current camera node address associated with each user by storing each node address in a particular memory location associate with that user. Similarly, each user&#39;s input is differentiated and identified as being associated with the particular memory location with the use of message tags appended to the user inputs by the corresponding user interface device. 
     In an alternate embodiment, two or more users may choose to be linked, thereby moving in tandem and having the same view of the environment. In such an embodiment, each includes identifying another user by his/her code to serve as a “guide”. In operation, the server provides the outputs and views selected by the guide user to both the guide and the other user selecting the guide. Another user input causes the server to unlink the users, thereby allowing each user to control his/her own movement through the array. 
     Embodiments Covered 
     Although the present invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art are also intended to be within the scope of this invention. Accordingly, the scope of the present invention is intended to be limited only by the claims appended hereto.