Abstract:
A multiuser, collaborative augmented reality (AR) system employs individual AR devices for viewing real-world anchors, that is, physical models that are recognizable to the camera and image processing module of the AR device. To mitigate ambiguous configurations when used in the collaborative mode, each anchor is registered with a server to ensure that only uniquely recognizable anchors are simultaneously active at a particular location. The system permits collaborative AR to span multiple sites, by associating a portal with an anchor at each site. Using the location of their corresponding AR device as a proxy for their position, AR renditions of the other participating users are provided. This AR system is particularly well suited for games.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/839,364, filed Jun. 25, 2013, which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to an augmented reality system. More particularly, it relates to a system and method for allowing multiple participants to share in an augmented reality session, based on the real-world location of one or more anchors. 
       BACKGROUND OF THE INVENTION 
       [0003]    Augmented reality (AR) toys have been introduced. The basic hardware required, an AR device, is a smartphone, laptop, tablet computer, dedicated device, or the like, that views the real world with a camera, and displays that view on a display to an user. Additionally, the AR device runs software that recognizes certain objects (herein termed “anchors”) in the camera&#39;s field of view, including the anchor&#39;s apparent distance and orientation relative to the camera, and then augments the image from the camera with computer generated graphics that seem to appear in, on, or near the anchor. The resulting modified image is displayed to the user (often, a game player, in which case, the AR device may also be executing game code). 
         [0004]    An example of such toys include a line of jigsaw puzzles, by Ravensburger AG of Ravensburg, Germany which when viewed with the corresponding AR app on an smartphone or tables replaces a portion of the puzzle with animated figures. Another one is called “AR Games” by Nintendo Co., Ltd. of Kyoto, Japan, which provides preprinted paper cards as anchors and plays on their Nintendo 3DS handheld gaming system. The Eclipse AR Card Game by MoOn-Studio of also uses preprinted cards as anchors, and allows two players to interact by manipulating the cards, however the two players share a single camera and display attached to a personal computer provides the same view to both players. 
       SUMMARY OF NEEDS UNSATISFIED BY PRIOR ART 
       [0005]    None of these games offers each of several players their own AR device (e.g., smartphone, tablet, or game system) to allow the players to each view the same anchors and see a mutually coherent augmented reality. 
         [0006]    Further, in cases where potentially duplicative anchors coexist in proximity to each other, prior AR systems do not resolve the resulting ambiguity. 
         [0007]    None of the existing AR systems insert a representation of the users into the AR in place of their own AR device, whether by recognizing the AR device as an anchor itself, or by having an AR device report its orientation and distance from another anchor. 
         [0008]    Finally, existing AR systems do not offer an ability to cojoin a first site having anchors and AR devices with anchors and AR devices at a second site, so as to give users at the distinct sites an apparently coherent AR world. 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0009]    The object of the present invention is to allow several players, each with their own AR device, to share a mutually coherent augmented reality. 
         [0010]    It is a further object of the present invention to mitigate the ambiguities that would otherwise occur if two like anchors were used near each other. 
         [0011]    It is a still further object of this invention to allow sharing of a mutually coherent augmented reality from otherwise distinct sites. 
         [0012]    Finally, it is an additional object of this invention to render into the augmented reality a representation of the users, whether AR devices are recognized as anchors by other AR devices, or by having an AR device report to other AR devices its own orientation and distance with respect to one or more other anchors 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The aspects of the present invention will be apparent upon consideration of the following detailed description taken in conjunction with the accompanying drawings, in which like referenced characters refer to like parts throughout, and in which: 
           [0014]      FIG. 1  is a block diagram of a collaborative AR system being used in a situation where there are two sessions going on, one with one player, and one with two players; 
           [0015]      FIG. 2  illustrates the detailed displays from the three AR devices in the system of  FIG. 1 ; 
           [0016]      FIG. 3  shows one example block diagram for an AR device, as might be implemented using a tablet; 
           [0017]      FIG. 4  is one example for a portion of a database accumulated and maintained locally by an AR device for operation in conjunction with other AR devices; 
           [0018]      FIG. 5  is one example database maintained by a server for facilitating joint AR sessions and mitigating collisions of identical anchors; 
           [0019]      FIG. 6  show one process for acquiring AR anchors for use in a shared AR session; 
           [0020]      FIG. 7  shows block diagram of another embodiment for a collaborative AR system, where multiple participants use anchors and AR devices at separate sites, yet share a coherent AR experience; and, 
           [0021]      FIG. 8  illustrates a detailed display from one AR device in the system of  FIG. 7 . 
       
    
    
       [0022]    While the invention will be described and disclosed in connection with certain preferred embodiments and procedures, it is not intended to limit the invention to those specific embodiments. Rather it is intended to cover all such alternative embodiments and modifications as fall within the spirit and scope of the invention. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0023]      FIG. 1  shows three AR users  101 ,  102 ,  103 , at site  100 , in this case players of an AR game, each having a corresponding AR device  110 ,  120 ,  130 . 
         [0024]    Each of the AR devices  110 ,  120 ,  130 , in this embodiment, has controls for use by respective user, e.g., button  111  and touchscreen display  112 . Each has a camera offering corresponding fields of view  114 ,  124 ,  134  and corresponding wireless connections  113 ,  123 ,  133  to wireless station  140  which offers connectivity, for example via Internet  141 , to server  142  having communication with database  143 . 
         [0025]      FIG. 1  shows two toy castles  150 ,  160 , used as anchors recognizable by the AR devices. In the prior art, if anchors were not absolutely unique, AR devices  110 ,  120 ,  130  could not determine whether their respective views of castles  150  and  160  would correspond to a single anchor, or whether they were distinct copies. For example, AR devices  110  and  120 , each viewing castle/anchor  150  could not be sure that there were not two castles that looked alike (castle  150  and a duplicate), or if there was only one castle  150 . 
         [0026]    In the present invention, even though the anchors are not strictly unique, the potential ambiguity is resolved by communication with server  142  in which each AR device registers the anchors it recognizes in conjunction with the general location of the AR device, for example as determined by GPS (Global Positioning System), cellular telephone or WiFi antenna proximity, etc. In this case, each of the AR devices  110 ,  120 ,  130  report proximity to wireless station  140 . An example series of transactions might go like this: First, AR device is directed by user  101  to start a session. AR device  110  recognizes an anchor (castle  150 ) and registers it in conjunction with the session just started with the location information identifying wireless station  140  (or perhaps GPS information obtained directly by AR device  110  or attributed to wireless station  140 ). Subsequently, player  102  attempts to play with AR device  120 . Player  102  can either explicitly join the session of player  101 , or AR device  120  can recognize the anchor that is castle  150  and report it to server  142 . If AR device  120  reports anchor  150  in conjunction with the location as determined by AR device  120  (which can include location information identifying wireless station  140 ), server  142  can respond that the anchor embodied in castle  150  is already assigned to a session belonging to player  101  and question whether player  102  wants to join the session of player  101 . In a case where AR device  120  reports that it is joining the session of AR device  110 , the anchors reported by AR device  120  are considered to be the same as like anchors reported by AR device  110  (i.e., castle  150 ). 
         [0027]    However, player  103  may choose to start a session of his own, using AR device  130 . AR device  130  determines its location, for example being proximate to wireless station  140 , or by GPS coordinate, etc., and recognizes castle  160  as an anchor in its field of view  134 . Initially, take the anchor provided by castle  160  as being a duplicate of castle  150 , that is, the AR devices cannot distinguish between them. When AR device  130  attempts to register castle  160  (then a duplicate of castle  150 ), at the same location as castle  150  is already registered, server  142  will ask whether player  103  is attempting to join the session of player  101 . Here, player  103  is not attempting to join a session already started, rather is attempting to start a second, independent session (which perhaps his friends, soon to arrive, will play with him). In this circumstance, server  142  must deny the registration of still-identical castle  160  to a separate session. It could be confused with castle  150  and actions by player  103  could inadvertantly and adversely affect game play corresponding to castle  150 . Instead, player  103  could use a different anchor (not shown here), or may modify castle  160  to make it recognizably distinct from castle  150  to the AR devices. In this example embodiment, castle  150  has two towers  151 ,  152 . As shown, castle  160 , once modified by removing a tower, has only one remaining, tower  161  (the tower removed from castle  160  is not shown). Instead of modifying towers, markers or labels (not shown) applied to various parts of castle  160  could be switched, or reoriented, or added. Pennants, small colored or patterned flags arranged on flagpoles where they can be easily seen and identified by the AR devices and recognition software, might be added, removed, or altered. 
         [0028]    As an anchor is being registered for a new session, server  142  might even propose the modification to be made. For example, server  142  might prescribe a particular pennant or sequence of pennants to a player starting a session. That way, any player directing his AR device at an anchor so configured will be automatically entered into the corresponding session having substantially the same location. Server  142  might prescribe the configuration for every anchor being added to a session, or may prescribe the configuration only for those anchors which seem to conflict with anchors already registered in session with a sufficiently similar location. 
         [0029]    In this case, “sufficiently similar location” would be established by policy. If GPS is used, this could mean within the accuracy of the GPS reading, plus an error band, times two, which might be 100 m or some other predetermined value, which may vary by the location itself (e.g., larger in cities and smaller in rural areas where GPS can be more accurate). The same is true of location services that use the cellular telephone network antennas for triangulation of location. If proximity to WiFi is used for location, “sufficiently similar” might be when both AR devices can detect the same WiFi antenna, though policy might limit that to detection with more than a predetermined signal strength (e.g., “two bars”, so many dBm, or miliwatts). 
         [0030]    Once multiple players have joined a common session, as with players  101  and  102 , the augmented reality views displayed by AR devices  110  and  120  are coherent, that is, they reflect the same augmented reality, even though the corresponding players views of that common augmented reality are different. This is shown clearly in  FIG. 2 , where AR devices  110 ,  120 ,  130  are shown (in this embodiment, each is a tablet). The touchscreen display  112  of AR device  110  shows image  210  in which castle  150  is shown from the vantage of field of view  114  as castle image  251 . The AR software has embellished this view of the castle with a computer generated dragon  212  just having set fire  213  to the far side of the castle. AR device  120  displays image  220 , showing castle  150  as seen in field of view  124 . The augmented reality elements of the dragon and fire are seen here, but since player  102  has a view of the back side of the castle, castle image  252  is seen with flames  223  coming out the near side with dragon  222  shown in the foreground. 
         [0031]    In some embodiments, when AR device  120  is in the field of view  114  of AR device  110 , AR device  120  may be recognized as an anchor having the role associated with player  202 . In such a case, in augmented reality image  210 , the anchor that is AR device  120  might be replaced by an appropriate visage  214  representing the viewpoint of the other player. 
         [0032]    In an alternative embodiment, the AR devices need not be recognized as anchors themselves, nor ever be detected by the other AR devices. In such a case, each AR device may determine its range from and orientation with respect to one or more anchors (e.g., castle  150 ) in the session, and report this information to the other AR devices, either directly or through server  142 . In this way, even when AR device  110  does not fall within the field of view  124  of AR device  120 , in AR image  220 , AR device  120  can place an indicator  224  to show in what direction the other player(s), i.e. player  101 , are located. This can be useful in a game context, to help a player anticipate what another player is thinking or doing, or where is attention is directed. This feature is particularly valuable with respect to games conducted across multiple sites, where direct viewing of the opposing player is not available, as discussed below in conjunction with  FIGS. 7 and 8 . 
         [0033]    Also in  FIG. 2 , the augmented reality image  230  displayed by AR device  130  is show, with image  263  of castle  160 . Here, no dragon is attacking the castle. Instead, a computer generated siege engine  232  is attacking the castle image  263 , and player  103  is engaged in a session separate from that which players  101  and  102  are enjoying together. 
         [0034]      FIG. 3  provides an example block diagram for AR device  110 . Processor (CPU)  310  uses memory  311  in which is stored the AR application software, corresponding data, and operating system code. Processor  310  directs graphic engine  312  which drives display  313 , which is overlayed by touch panel  314  which together form touchscreen  112 . Touch panel  314  is monitored by touch interface electronics  315 , which report user interactions back to processor  310 . Other user interface devices, such as button  111  are monitored by other I/O interface  316 , also reporting to processor  310 . Camera  317  provides an image for field of view  114 , which is made available to image processor  318  (which could be a software module instead of hardware) wherein the recognition of anchors is performed. Location sensor  319  may comprise one or more of a GPS receiver, accelerometers (for detecting the attitude of AR device  110 ), gyroscopes (for quickly detecting the magnitude of sudden changes, but also for detecting very slow changes), flux gate compasses (to detect bearing relative to the Earth&#39;s magnetic field), etc., all of which have communication with processor  310 , either directly or, in some embodiments, through intermediary utility processors (not shown) Finally, processor  310  has access to network communication channel  320 , for example, a wireless connection as to station  140 , through which communication is available with server  142  and in some embodiments, other AR devices (e.g.,  120 ). 
         [0035]    In some embodiments the functions of server  142  may be performed by one of the AR devices, for example the AR device that starts a session, or may be distributed among some or all of the AR devices at a location. For example, an AR device attempting to start a new session might broadcast a signal soliciting information about other sessions or anchors already in use. The response, if any, might indicate which anchors are already in use, in which sessions, and may further suggest other alternate configurations of selected anchors that might be used instead. 
         [0036]      FIG. 4  shows one example of portion  400  of a local database used to keep track of which anchors, wireless stations, and the AR devices known to one AR device (e.g.,  110 ). While illustrated using a relational database connection, those skilled in the art will recognize that many other alternative choices for data representation could be applied and that this representation was chosen for clarity in this example. Device table  410  identifies each distinct AR device (including itself) by a unique identifier, ARDeviceID, which could be a globally unique identifier (GUID) or universally unique identifier (UUID), well known in the art, or other identifier that will not be repeated among other AR devices in the system. The ARDeviceID for the device itself might be provided at the time of manufacture, or by server  142  when AR device  110  first registers itself with the system. The table  410  also includes information relating to one or more communication addresses for each device, e.g., an IP (Internet Protocol) address, MAC (Media Access Control) address, etc. This allows individual AR devices to communicate with other AR devices without going though server  142 . One or more security keys may be provided, for example a public/private key, so as to allow a server to communicate securely and authoritatively to an AR device (for example, to supply a software update or carry out a financial transaction), in which case the AR device holds the public key for the server and the server uses its private key to sign or encrypt messages it sends; or if a message is to be authenticated as coming from the AR device, the AR device would use its private key to sign or encrypt the message and the public key (which is the only portion distributed to the server or other devices), would be used to authenticate the message upon receipt. The current attitude and orientation in space (e.g., as determined by accelerometers, gyros, and magnetic compasses in location sensor  319 ) would be stored in the attitude field, whether obtained from its own sensors or received in communications from other AR devices. Likewise, latitude and longitude, if available whether from GPS or other location service, would be noted. Exactly one player identity (discussed below in conjunction with table  425 ) is associated via relationship  412  whenever the AR device is participating in a shared session, but need not be otherwise. Other fields, not shown, for example, when each AR device was first or most recently contacted might also be recorded here, for example, to determine the age of the attitude and position information. 
         [0037]    Table  420  stores information about users of the device, for example their username and authentication. There might be only one record in this table, if the device has only one user. Each user record in table  420  may correspond to zero or more player personae, recorded in player table  425 , each having a unique player ID. Each player record is associated with, at most, one user record by the UserID field that forms relationship  421  (Note: Players on other AR devices need not have a corresponding user record on this AR device). Additionally, the player name field records the in-game name for the player, which could be their game character&#39;s name. Other fields (not shown) might include or reference a player-specific icon or image; for example, each player might have a unique visage for use when augmented reality scenes are rendered (e.g., for visage  214 , if it is to be specific to the player, rather than generic or determined by some other game mechanic). Player status, such as ‘INACTIVE’ for all players not currently playing, or other game-mediated states would be entered for the local player and could be sent to other AR devices during a session. Likewise, messages describing players received from other AR devices would be gathered here. 
         [0038]    In one embodiment, anchors table  430  is constant, or could be authoritatively updated, for example by server  142 . In it, the collective records represent a canonical description of each of the available anchors. A representation of the patterns that identify each kind of anchor, including the possible configuration variations, is provided sufficient to inform the image processing module  318  what to look for in the camera image, as to what constitutes an anchor to be recognized. Also included is a field describing in detail the geometry of the anchor (e.g., the geometric shape of castle  150 ), sufficient so that graphics engine module  312  can orient the geometry of the anchor to the recognized patterns, so that when the camera image is being augmented, the geometry model can be used to enhance the rendition of the final image. For example, in AR image  210 , the geometry of the castle anchor is used to mask flames  213  so that they appear behind the castle image  251  obtained from the camera, whereas in AR image  220 , the flames  223  are in front of the castle, but appear to be emanating from a particular window. Additional information (not shown) concerning anchor-specific animations or embellishments that might be added under certain conditions (e.g., how rain should funnel off the roof, or how the walls should look after receiving a certain amount of damage), might also be recorded here. Updates to table  430  would occur if the manufacturer offers new anchors, or if updates to the existing catalog of anchors were to be made. 
         [0039]    In some embodiments, alternative patterns may also be included. This would allow readily available objects (e.g., a can from a particular brand of soda) to be used in lieu of castle model  150 . In such a case, the geometry information in table  430  would be used to render the castle image  251 , because the un-augmented camera image would show a soda can. 
         [0040]    In other embodiments, a catalog of anchors could be provided, but dynamically associated with a physical representation (i.e., the pattern), so that a user could make their own anchors, e.g., by printing a suitable barcode on paper, registering that barcode as a pattern associated with a particular anchor record, thereby allowing the printout to be used as the anchor (e.g., in lieu of castle model  150 ). This would allow a player new to the hobby to quickly set up a complex AR scenario having multiple anchors, without requiring that user to acquire multiple, elaborate physical models such as castle  150 . Later, if the user remains interested, the physical models can be acquired. The system may react to the difference between the actual physical model (e.g., castle  150 ) and the printed proxy, for example by reserving certain features or game capabilities associated with the castle anchor for sessions in which the actual castle model  150  is being used. 
         [0041]    A user inventory of anchors a user owns can be maintained in table  437 , allowing the system to keep track of which physical anchors (e.g., castle  150 ) a user owns. Table  437  implements a many-to-many relationship, with each record identifying that a particular user  432  owns a copy of a particular anchor  433 . This information can be useful if a server needs to suggest that a different anchor be used because a requested anchor is already committed in a nearby session. The count field would generally be ‘1’, but if a user owned duplicate anchors, the count could indicate how many copies. 
         [0042]    Table  435  stores records about the status of anchors that have been joined to (that is, associated with) the current session. The specific anchors detected are identified by relationship  431 , and the current configuration of each is noted. If a newly detected anchor is duplicative of another already in use at this site, the server may recommend a different configuration than the one currently in place (for example, where player  303  removed one of the towers from castle  160 ), or disallow use of the anchor (for example, if all the configurations are already in use nearby, or there are no alternative configurations). If an anchor is accepted into a session, the corresponding joined anchor record is provided with a JoinedAnchorID that provides a unique reference to that specific anchor so that other participating AR devices and server  142  can refer to the anchor unambiguously. The record is further augmented with the identification of which AR device (in table  410 ) controls the game state of this anchor. Likewise, other information about the anchor may be included, for instance its role (e.g., some anchors are for active play, some may be decoration, some anchors may have been detected, but not joined into the game). Status can comprise many components, as in  FIG. 2 , anchor  150  (shown as castle images  251 ,  252 ) exhibits a status being attacked by a dragon (shown as dragon images  212 ,  222 ) and being on fire in the second story of the back side of the main tower (resulting in flame images  213 ,  223 ). The corresponding controlling AR device would be executing the appropriate code so that the status advances appropriately, e.g., the fire spreads, the dragon may come under attack by the castle defenders, etc., which would further update the status. Such updates would be propagated to other AR devices participating in the shared AR session so that the AR images  210 ,  220  present coherent representations of a shared augmented reality. Lastly, table  435  includes a timebase initialized by the controlling AR device (or alternatively by server  142 ) so that other AR devices have the opportunity to synchronize their representations of status applied to each anchor. For example, if at some point in the progress of the fire that augments images of anchor  150  there is an explosion, it is desirable for the video of the explosion and any sound that might correspond to that event be substantially synchronized, so that players  101  and  102  experience the event and their reaction to it is also simultaneous, thereby reinforcing the coherence of the augmented reality presented by devices  110 ,  120 . If multiple different activities are proceeding with respect to an anchor, for example the fire, dragon attack, defenders (not shown) on the parapets, a thief scaling a wall, each activity represented in the status of the detected anchor may have its own timebase. 
         [0043]    Once an anchor has been joined into a session, each participating AR device may begin tracking, recording, and reporting its range, bearing, and orientation with respect to each of the joined anchors. This is shown in table  415 , which uniquely relates an AR device (via relationship  411 ) to a joined anchor (via relationship  432 ) and then logs range, bearing, and orientation, relative to that anchor in the corresponding record. Often, one or more joined anchors may be out of an AR device&#39;s current field of view, in which case, the information presented therein may become stale. For this reason, a field is also maintained to record the last update time, so that an entry that is several minutes old might be recognized as possibly being out of date. Even when an anchor is no longer in the field of view of an AR device, the AR device may extrapolate its relationship to that anchor by considering information from its location sensors  319  (e.g., accelerometers, gyros, compass, etc), which may be sufficient for some tracking purposes, at least for a short while. A flag (not shown) in each record may indicate whether or not the record is extrapolated, and when it&#39;s last actual observation of the anchor occurred. 
         [0044]    Detected station table  445  keeps track of wireless stations  140  that an AR device is currently detecting. The MAC (media access control) address can be used to identify such stations unambiguously, but a separate station ID is used to keep individual track of the detection records, since more than one AR device might simultaneously be detecting each station. The strength of that detection may also be noted, which may serve as an indicator of distance from that station. By policy, one AR device detecting a particular station with a strong signal may or may not be considered proximal to another AR device detecting that same station with a much weaker signal, for the purposes of this invention. A longer-term record for stations historically detected may be kept in station table  440 , with which records in detected stations table  445  are associated by relationship  441 . If a station reports its location, or is otherwise able to be associated with a latitude and longitude, this data can be recorded in these records, but is not strictly required, though it can be useful for determining the location of an AR device. 
         [0045]      FIG. 5  shows a portion of the master database  500  and its association with the various local databases  400  maintained by each AR device. Records  410 B,  415 B,  425 B,  435 B, and  445 B represent individual records received from or sent to individual AR devices, corresponding to their similarly numbered tables (without the ‘B’). Received records (or messages having similar content) provide updates to the master database  500 , while updates to the individual AR devices can take similar form when sent and keep all the session participants updated. Upon receipt by server  142 , such records can be forwarded to other AR devices participating in the same session, though in some implementations this need not be done if the information is already communicated to the other AR devices by the originating AR device directly. 
         [0046]    Table  501  tracks ongoing sessions and their current location, for example by determining their latitude and longitude of one or more of the participating AR devices. In some embodiments, a field may be included to identify which player ‘owns’ the session (not shown in table  501 ), for instance for use implementations where a new player attempting to join a session is to be a session-owner moderated event, then the session must be able to identify its owner so that the owner can decide whether to admit the new player. 
         [0047]    When a record  410 B is received, it can be associated with a pre-existing record in table  510  if relationship  512  identifies a record, otherwise, then a record  410 B can be inserted into table  510 , which is used to track devices present associated with ongoing session. In table  510 , the SessionID field forms relationship  511  associated each AR device with exactly one session. 
         [0048]    Player records  425 B, through relationship  522 , populate and update records in table  520  for tracking players currently in the ongoing sessions in table  501  and identified by relationship  521 . When an AR device in represented by a record in table  510  is participating in a session, there will be (in this embodiment) exactly one corresponding player in table  520  associated with each AR device via relationship  523 . 
         [0049]    Station detected records  445 B, through relationship  542  populate and update records in table  540  for tracking stations that seems to be near the session identified by relationship  541 . Server  142  may keep a long term database of stations identified in table  550 , which may be populated via relationship  545 , and updated (in case latitude or longitude changes, as might be the case if a station gets relocated or the estimate of its position is refined). 
         [0050]    Joined anchors records  435 B, through relationship  532 , populate and update the anchors-in-session table  530 , associated a joined anchor with a particular session identified by relationship  531 . 
         [0051]    Table  515  contains records analogous to those in table  415 , and is populated and updated by the records  415 B received from individual AR device. (In  FIG. 5 , the record  415 B is shown redacted due to space concerns, though the whole of the record is transferred). In records  415 B, the two fields ARDeviceID and JoinedAnchorID form a composite foreign key used to form relation  517  to identify records in table  515 . Relationship  516  between the device-in-session table  510  and table  515  associates AR devices and the record of their physical position relative to the active anchors listed in table  530  and associated via relationship  533 . 
         [0052]    In each case, for inbound records  410 B,  425 B,  435 B and  445 B, the insertion or update of records into the corresponding tables  510 ,  520 ,  530 , and  540  includes the additional information of with which session to associate the incoming record. Whether the session identity is explicitly provided by the AR device sending the record, or whether the server  142  determines the session identity on the basis of the AR device sending the message (or the IP address from which the message is sent) is an implementation detail readily solved by those skilled in the art. 
         [0053]    Table  560  is the authoritative catalog of anchors that can be used to keep tables  430  in local database  400  up-to-date as new anchors become available from the manufacturer. 
         [0054]    Example process  600  for starting or enrolling in a session and joining anchors to that session is shown in  FIG. 6 , wherein at  601  an AR device, e.g.,  110 , is directed by the user to initiate or join a session. At  602 , using location sensors  319  (e.g., GPS or other locator service) the location of the AR device is obtained or estimated, if possible, and recorded in local database  400 , e.g., in the corresponding record in table  410 . At  603 , any stations detected, such as station  140 , are logged in local database  400 , in records of table  445 . If the stations are new, they can be added to table  440  also. If the location could not be determined at  602 , or is otherwise considered to be of low accuracy, a currently or previously determined location corresponding to the stations currently detected at  603  may be used to refine the estimate of the current location. 
         [0055]    At  604 , a transaction is attempted with server  142 , to request a new session, or to join an already existing session. As part of the transaction, information concerning the AR device, including its location, is provided. The location information may comprise some or all of the stations currently (or recently) detected, as logged in table  445 . Server  142  accepts any request for a new session, and responds to a request to join a session with a list of available sessions proximal to the location of the AR device. If only one nearby session is available, the response may be automatically joined to that session without a further query from server  142  back to the requestor as to which nearby session to join. If, as a matter of policy, the initiator of a session (the session&#39;s “owner”) controls who may join the session, then permission to join the session may wait for a response from the session owner. In some embodiments, discussed below in conjunction with  FIGS. 7 &amp; 8 , one might join a session that is not nearby, in which case the choice of which session to join may be made using the player name of the owner or in response to an invitation (not shown) from the owner, which might identify the session by the SessionID field in table  501 , or similar mechanism. 
         [0056]    Upon joining a session in progress, information in those records in tables  510 ,  515 ,  520 ,  530 , and  540  having an association with the session just joined are sent to the AR device just joining, thereby adding records corresponding to the session tables  410 ,  415 ,  425 ,  435 , and  445 , allowing an augmented reality to be presented coherently over the multiple participating AR devices. 
         [0057]    Once having initiated or joined a session at  604 , processing continues at  605  where anchors, such as castle  150 , are detected when corresponding field of view  114  of camera  317  captures an image of the anchor (castle  150 ) which is then recognized by image processor module  318  as corresponding to an anchor record in table  430 . At  606  a check is made by examining local database  400  to see if that anchor is already listed in joined anchors table  435 , in the configuration noted by image processor module  318 . If not, then the anchor is new to this session and server  142  is queried at  607  to determine whether the new anchor will be admitted. 
         [0058]    Server  142  determines whether the new anchor is allowable by checking to see whether any copies of that anchor in the observed configuration are already registered in table  530  to another session having a location too close by (as determined by policy) or which is associated with nearby stations listed in table  540  that are also associated with the current session requesting the anchor. If either of these is the case, the anchor in its current configuration is rejected at  609 . The server  142  may recommend a particular different configuration for the anchor detected at  605 , which might be computed by the server by examining nearby sessions for all configurations of the same anchor, and removing those from a list of possible configurations as determined by the pattern information in the anchor catalog  560 . If there are no available configurations for that particular anchor, the server  142  may report this, too, whereby the player is saved from fruitlessly trying numerous configurations that would not have a chance of succeeding. A further computation could determine for which anchors in the players personal inventory, as represented by table  437 , there are available configurations, though this may require server  142  obtaining a copy of table  437 , which could be achieved by the above methods used to synchronize the various tables. The result of such advice would be that the player is provided with likely-to-succeed suggestions for other anchors that might be used. Once the proposed anchor has been rejected at  609 , processing tests to see whether the session has been terminated at  613 , and if not, loops back to  605 . If at  608  the determination from server  142  is that the anchor is allowed, then a corresponding record is added to master joined anchors table  530  and propagated via transmission record  435 B to be recorded in the joined anchor table  435  of each of the AR devices participating in the same session. Server  142  may set the controlling AR device field in the corresponding joined anchor record to identify the requesting AR device, or may choose a different AR device if the requestor is becoming overloaded (e.g., for being the controller of too many anchors). 
         [0059]    After a new anchor is allowed at  608 , processing continues at  610 . At  606 , the anchor and configuration recognized at  605  may be found to already be represented in table  435 , which may be because it was previously added following an allowance at  608  or because it was already a part of the session before this AR device joined in and was populated during  604 . If this is the case, then at  606  the anchor is determined to not be new, and here too, processing continues at  610 . 
         [0060]    At  610 , the controlling AR device field in the corresponding joined anchor record in table  435  is examined. If the field indicates that this AR device is the controller, then at  611  the AR devices begins to initialize the game processes corresponding to that anchor as defined in at least the corresponding record in anchor catalog  430 . As the anchor management activity at  611  has been dispatched (e.g., on other processing threads), process  600  continues at  613  as before. In some embodiments, this same initialization may be performed when a newly assigned controller receives an update message  435 B in which it is assigned the controllership of a new anchor, but one added to the session by a different AR device. In still other embodiments, an AR device might be passed the controllership of an anchor by the previously controlling AR device, for example when the previous controller is leaving the session, or communication with it has otherwise been lost. 
         [0061]    At  611 , interaction with the anchor, other than initializing it, may be performed. This is especially true in subsequent passes, once the game gets going. 
         [0062]    If at  610  the management of the present anchor is not the responsibility of the current AR device (i.e., the controlling AR device field does not match the current AR device), then at  612 , any interaction with the anchor is directed to its current controller, either directly via station  140  (or other communication mechanism, e.g., Bluetooth™), or via server  142 . 
         [0063]    The interactions that can take place directly at  611  or indirectly at  612  are how the anchor and its augmented reality components are made interactive. For example a player may direct the defenders of castle  150  to counter attack the dragon, or task them with knocking back the fire. Interactions with the AR rendition of the castle may allow walls to be opened so that the activities inside can be examined, etc. In other scenarios with different anchors, for example representing spaceships, the augmented reality display may present controls for the augmented anchors that increase their shields, fire their weapons, or otherwise provide an interactive interface to the anchor&#39;s augmented rendition. The capabilities of such interactions are the essence of the game design. 
         [0064]    Some interactions may be limited to certain players, regardless of which AR device is the controller. For example, the player designated as the occupant of the castle (a game-specific state not explicitly represented in the database as illustrated, outside of the joined anchor&#39;s ‘status’ or ‘role’ fields) may be allowed defensive interactions, e.g., closing the gates, placing the guard on alert, etc., and provided with comprehensive status and reporting, since all, or at least most, of the virtual personnel in the castle are his to command. Another player may be provided with a different set of interactions, e.g., transacting in the castle market place, or sending a thief to scale the walls, or attacking it with a dragon. 
         [0065]    As before, at  613 , if the session has not ended, the process returns to  605 . Each anchor in the current field of view may be detected. As the session progresses, only previously added anchors are being identified at  606 , and the interactions with them, whether at  611  or  612  represent the bulk of the activity of process  600  for most of the session&#39;s duration. Also at either  611  or  612 , if the range, bearing, or orientation of the AR device with respect to the detected anchor has changed, then an update may be made to the corresponding record in table  415 , and at least occasionally sent (e.g., every 10 seconds, up to a few times per second) to server  142  as update records  415 B which are then propagated to the other participating AR devices. 
         [0066]    If at  613  the session has ended, or the player of the current AR device has decided to quit, then at  614  the anchors are released, or assigned to other controlling AR devices, and this is communicated to server  142 . If the session is over, all associated records in tables  510 ,  515 ,  520 ,  530 ,  540  are deleted from master database  500  and tables  435  and  415  are cleared in local database  400 . 
         [0067]      FIG. 7  shows a different configuration of the system, where a common augmented reality is shared at two different sites,  710  and  750 . Each site has its own wireless station  740  and  751 , respectively, each having communication through the Internet  741  to the shared augmented reality server  742  having database  743  comprising, in one example embodiment, master database portion  500 , discussed above. 
         [0068]    At site  710 , player  711  uses AR device  720  having wireless communication link  723  to station  740 . AR device  720 , comprising touchscreen  722 , has field of view  724 , which at least occasionally includes anchor  730  (another castle) and anchor  731  (an arch). 
         [0069]    At site  750 , player  751  uses AR device  760  having wireless communication link  763  to station  751 . AR device  760  has field of view  764  that at least occasionally includes anchor  770  (another castle which need not be distinct from anchor  770 , since they are at different sites), and anchor  771  (another arch). 
         [0070]    In this configuration, the two arches  731  &amp;  771  are given the role in tables  435  and  530  of portals to their corresponding sites. With that definition, the AR software running on processor  310  can link the two sites  710  and  750  in a shared augmented reality for players  711  and  751 . This is achieved by first collecting and then analyzing the records in table  415 . On occasions where AR device  760  simultaneously sees and recognizes both of anchors  770  and  771 , the physical relationship between the two anchors  770  and  771  is established, as well as the relationship between those anchors and AR device  760 . This information is relayed to AR device  720 , which can map the arch  771  at site  750  as being in coincidence with the other side of arch  731  at site  710 . With this mapping, the augmented reality image  810 , shown in detail in  FIG. 8 , can be generated: A graphic rendition  870  of the castle corresponding to remote anchor  770  can be provided by graphics engine module  312 , along with a rendition  860  of player  751  as a game character located in coincidence with the AR position and attitude of remote AR device  760 . Meanwhile, the castle image  830  is obtained of local castle  730 , and the dragon  812  and fire  813  graphically generated as previously discussed. 
         [0071]    The rendition  860  of a character whose gaze is directed by the field of view of another player&#39;s AR device (here,  760 ) provides insight into what the other player is thinking, studying, watching, controlling, even though that player is remotely located and potentially not otherwise viewable. 
         [0072]    In another embodiment, the plane of the portal may be defined with respect to an anchor, but not necessarily be coincident with it. That is, for example, the portal that joins the two sites in the augmented reality may be a vertical plane that is set back some distance, say three feet, from a particular anchor, say the castle  730 , in a particular direction, say the direction of the main gate. In this embodiment, arch  731  is not needed. Thus, when view through an AR device, anchors that exist physically only at the other site (e.g., castle  770 ) would appear through the AR device to lie beyond a portal three feet in front of the local toy castle&#39;s main gate. The AR image  810  in  FIG. 8  would be the same, except the image of arch  831  would not be required, since arch  831  was not needed to define the portal. 
         [0073]    The particular implementations described, and the discussions regarding details, and the specifics of the figures included herein, are purely exemplary; these implementations and the examples of them, may be modified, rearranged and/or enhanced without departing from the principles of the present invention. In particular, the computer architectures, data structures, and flowcharts herein are exemplary, and significant alteration can be made without departing from the spirit of the invention. As previously mentioned, the choice of a relational database for the representation and explanation of example data management and structures can be readily substituted with other equally effective mechanisms. 
         [0074]    Particular features of user interface, image processing module, graphics engine module, and the capabilities of the databases, will depend on the architecture used to implement a system of the present invention, the operating systems of the servers, and AR devices, the CPU selected, and the software code written for them. It is not necessary to describe the details of such programming to permit a person or team of ordinary skill in the art to implement the application, user interface, and services suitable for implementing a system within the scope of the present invention. The details of the software design and programming necessary to implement the principles of the present invention are readily understood from the description herein. 
         [0075]    Various additional modifications to the embodiments of the invention, specifically illustrated and described herein, will be apparent to those skilled in the art, particularly in light of the teachings of this invention. Further, it will be apparent that the functionality of this invention can be incorporated into and function from within the context of other products, including an e-commerce system. It is intended that these cover all modifications and embodiments that fall within the spirit and scope of the invention. Thus, while preferred embodiments of the present invention have been disclosed, it will be appreciated that it is not limited thereto but may be otherwise embodied within the scope of the following claims.