Abstract:
A security monitoring system providing security for mobile objects in any location, including children in a dining and child entertainment facility. The location of each object or child in the facility is tracked using a transmitter attached to the object or child when it/they enter the facility, and a video image of each child is mapped to and displayed on a video display at a table to which the child&#39;s family or group is assigned. Any unauthorized attempt at removing a child from the facility, or at a child attempting to leave the facility without authorization, or unauthorized removal of a transmitter, or a transmitter ceasing to operate, causes notification to be given to appropriate personnel and entrance/exits are locked until the child is located. Ordering of food and drinks is done using touch screen technology on the video display at each table. The transmitters can also be used to control access to video games or specific play areas as specified by a parent or guardian. When playing video games or using play facilities for which there is an extra charge, the transmitters are used for authorizing access and for billing purposes. To map physical positions within the facility to positions on a video display, a transmitter is placed in various locations about the facility and the touch screen video display is used to map the physical positions with positions on the video display for different video cameras.

Description:
FIELD OF THE INVENTION 
     This invention relates to a security monitoring system and more particularly to a system for monitoring the location of, and providing security for, any mobile objects including small children. 
     BACKGROUND OF THE INVENTION 
     In the prior art a number of security and object location systems are taught. In U.S. Pat. No. 5,543,797 a monitoring system is described for monitoring the location of mobile objects in a structure. This monitoring system provides an R. F. transponder for each mobile object or person. A number of transceivers are position around the monitored structure to receive transmitted signals from the transponders. Each transponder periodically transmits a unique identification code that is received by one or more of the transceivers that are closest thereto. The transceivers measure the strength of the signals received from the transponders and forward this information to a central controller. The central controller knows that a transponder is located in an area around the particular transceiver that measures and indicates the highest signal strength. The central controller can transmit commands through the particular transceivers to selected transponders, including audible messages to a person having a transponder, via an earphone. However, this monitoring system can only indicate a general area in which a specific transponder is located. It cannot provide a fairly specific position at which a specific transponder is located. 
     U.S. Pat. No. 3,419,865 teaches an arrangement for continuously determining and displaying the location of a number of mobile police vehicles for the purpose of indicating their exact relative locations within a metropolitan area. Each police vehicle has a transceiver that periodically transmits an identification signal within an assigned time slot in a time division multiplexing arrangement. An identification signal is received by at least three stationary receivers, each having clocks synchronized to a central master clock. The physical position of a vehicle is reflected in the time difference that the identification signal transmitted from the vehicle is received at each receiver. This information is transmitted back to a central computer that calculates the position of the vehicle on a map relative to the position of the stationary receivers. This arrangement will not work in an environment of adjacent rooms where it is desired to locate transceivers in each room, because radio waves generated by a transceiver in one room will travel through the walls and be received by receivers in adjacent rooms. 
     U.S. Pat. No. 5,512,879 teaches apparatus for preventing infant mix ups and kidnappings in hospitals. A miniature electronic security tag is affixed to the ankle of a newborn infant. Periodically, the tag transmits a unique encoded identity signal that is received by strategically placed radio receivers within a hospital. Attempts to remove a tag are detected and transmitted to the receivers. A central computer continuously determines the identity and location of each tagged infant in the hospital. In the event that an unauthorized person attempts to leave the hospital or a smaller monitored area with an infant, or if a tag is removed, an alarm is sounded. However, this monitoring apparatus only detects if an infant having a security tag is taken through a doorway equipped with a monitor receiver. It does not indicate the location of an infant within a larger area. 
     Thus, there is a need in the prior art for a security monitoring system that monitors the exact location of, and providing security for, mobile objects including children. 
     SUMMARY OF THE INVENTION 
     The foregoing need in the prior art is satisfied by the present invention. A security monitoring system is disclosed which monitors the location of, and provides security for, mobile objects including children and adults. A building having many rooms has a plurality of ultrasonic receivers and video cameras in each room. Each mobile object has an omni-directional ultrasonic transceiver that periodically transmits a distinctive encoded ultrasonic signal that is received by at least three ultrasonic receivers in the room in which the mobile object is located. The signals received by the plurality of ultrasonic receivers in each room are processed by a sensor processor associated with the ultrasonic receivers in each room using the propagation delays that the ultrasonic signal arrives at the different receivers in the room to triangulate and locate the exact position of the mobile object in the room. In this manner the location of each ultrasonic transceiver and its associated mobile object are always known and are stored in the computer. Examples of use of the invention are to keep track of prisoners in a penal institution, to keep track of patients and personnel in a care facility such as a mental or other type of hospital, and to keep track of children in a play facility. It is the latter use that is described herein. 
     There is a plurality of conventional security video cameras in each room, and each camera is used to visually monitor an area in the room in which the camera is located. A zoom function may be accomplished by electronically expanding a portion of the video output from a camera. In this manner the same original picture from a video camera may be used to create zoom pictures for a number of children in the view area of the camera. 
     To provide security services the central computer is programmed with information indicating what rooms in the building each mobile object is authorized to enter. If a mobile object attempts to enter an unauthorized room, an access door may be locked or kept locked, an alarm may be sounded at the site of the mobile object and/or at the central computer site, and a camera may be zoomed on the mobile object that caused the alarm to be sounded. The video signal from any selected camera may also be recorded. To implement such access control, turnstile gates and other access limiting devices may also be used, instead of a locked door, so that a child authorized to enter a certain area cannot give access to that area to a child that is not permitted access thereto. Alternatively, a centrally located attendant that has a video view of the entrance to each room may control the opening of the door or gate to each room after a transceiver worn by a child is sensed and checked. 
     The novel arrangement described above can advantageously be used to monitor and locate the exact position of children in a combined dining and child entertainment facility where a family or other group goes to eat and play, and the young children get to securely play in play areas. A family enters such a restaurant via one or more controlled entrances/exits where they are registered and assigned a table. The children each have a small ultrasonic transceiver attached to them that cannot easily be removed. Each transceiver is registered to each child during their visit. 
     At the assigned table there is one or more video stations that have graphical user interfaces with touch screen operation. A trackball, joystick, or computer mouse may also be used. There are playrooms that are typically located around the periphery of the dining and entertainment facility where the children can go to play while their parents sit at the assigned table. Within each room, including playrooms, dining room, lobby and bathrooms there are multiple ultrasonic receivers that receive the ultrasonic signals from each child&#39;s transceiver that is located in the room. The received signals from each room are fed to sensor processor that processes the propagation delays from all transceivers to their surrounding ultrasonic receivers to triangulate the position of each transceiver in each room and sends the location information to the central computer. In this manner the exact location of every child in the dining and entertainment facility is always known. If a child attempts to leave the dining and entertainment facility on their own, or an unauthorized attempt is made to take them out of the dining and entertainment facility via an entrance/exit this is detected, or a transceiver is removed in an unauthorized manner, or a transceiver ceases its periodic transmission, an alarm is sounded and the entrance/exit is locked until the matter is resolved. 
     At the table the parents may utilize the touch screen operation on a video station at the table to view the food menu, place food orders, and to view their children at play. To view their child a parent presses the touch screen at an appropriate spot. Responsive thereto the central computer looks up the present physical location of the ultrasonic transceiver of the child or children assigned to the table in its memory. The computer then routes the video signal from the video camera in the field of view of which the child is presently located back to the table where the child&#39;s parents are sitting and the picture is displayed on the video station at the table. The parent that requested the picture may send another touch screen entry request to do a close up of the child. Responsive thereto the computer selects a portion of the same video signal and performs an electronic zoom, is well known in the video art, to create a close up picture of the child that is returned to the video station at the table. To perform this zoom function the central computer uses the stored location of the child to determine what portion of the camera video signal is to be used for the electronic zoom. When there is more than one child, and a viewing request is made for each child, the computer creates a split screen operation on the video station and routes the video signal or electronically zoomed video signal for each child to the video display at the table. 
     In addition, there is a loudspeaker mounted in each room and playroom that may be used by the management for paging or other purposes. Parents may also utilize the touch screen video station at their table, which is also equipped with a microphone/loudspeaker, to page a child or to send a brief oral message to a child who is being viewed on their video station. Preferably, the transceiver on each child may be equipped with the ability to give an audible page/buzzer signal to a child, and to receive and give a voice message from the child&#39;s assigned table to the child. The touch screen video stations may also be used to see facility personnel and orally communicate with them to place food and drink orders, and to communicate with the reception desk. 
     During installation and setup of the ultrasonic sensors and ultrasonic signal processing equipment, video cameras, and video stations a procedure is followed to correlate what is seen on the screens of the video stations with what the position of ultrasonic transmitters are within a room as determined by the ultrasonic signal processing equipment. This is accomplished by positioning an ultrasonic transmitter in specific locations within a room, such as in corners and at locations that appear on the edge of the video station screen and then touching the image of the transmitter on the video station screen. The system records the screen locations, as determined by the touch screen circuitry, and correlates that information with the output of the ultrasonic sensors and ultrasonic signal processing equipment. In actual operation a processor in the system interpolates position information of an ultrasonic transmitter with a screen location to know where a child wearing the transmitter is located to determine what video camera image is to be used to display an image of the child on a video station screen, and what portion of the overall image to blow up for a close up of a child. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood upon reading the following detailed description in conjunction with the drawing in which: 
         FIG. 1  shows a general floor plan of a dining and entertainment facility in accordance with the teaching of the preferred embodiment of the invention; 
         FIG. 2  shows a block diagram depicting a processor based system used to implement the present invention; 
         FIG. 3  is a flow chart depicting the logic involved in the software running a processor in the processor based system used to implement the present invention; 
         FIG. 4  is a flow chart showing more detail of a portion of the flow chart in  FIG. 3 ; 
         FIG. 5  is a flow chart showing more detail of a portion of the flow chart in  FIG. 4 ; 
         FIG. 6  is a flow chart showing more detail of a portion of the flow chart in  FIG. 5 . 
         FIG. 7  is a side view of a room and the angles of view of video cameras in the room; 
         FIG. 8  shows the view of one video camera in a room during system setup; and 
         FIG. 9  shows the view of a second video camera in the same room during system setup. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a general floor plan of a dining and entertainment facility  10  utilizing the security monitoring equipment in accordance with the teaching of the preferred embodiment of the invention. 
     Dining and entertainment facility  10  is primarily for children and has play areas such as presently exist around the country. Examples are Burger King, McDonalds and Chuck-E-Cheese. Facility  10  has one or more exterior entrance/exit doors  22 , an entrance foyer  11 , a dining area  12 , play areas  13 ,  14  &amp;  15 , bathrooms  16  and  17 , a kitchen  18  where food and drink our prepared, a storage area  19 , an office  20 , and an equipment room  33  in which is located a central computer, recording, and video and audio switching equipment (not shown) which are used to implement the present invention. 
     Located throughout facility  10  are a plurality of ultrasonic sensors  29   a – 29   s  that are generally mounted high on a wall, a plurality of video cameras  30   a – 30   k  that are also generally mounted high on a wall, and touch screen video stations  28   a – 28   k  located on dining tables  26   a – 26   g , at reception  23 , in kitchen  18 , and office  20 . In addition, there is a speaker  31 ( a–h ) located in all rooms including each of play areas  13 ,  14  &amp;  15  for paging and other communication purposes. More specifically, speaker  31   a  is located in play area  13 , speaker  31   b  is located in play area  14 , speaker  31   c  is located in video game play area  15 , speakers  31   d &amp; h  are located in dining area  12 , speaker  31   e  is located in kitchen  18 , speaker  31   f  is located in bathroom  16  and speaker  31   g  is located in bathroom  17 . Speakers  31   a – 31   h  are used to communicate short messages from parents to their children in the play areas and by personnel of facility  10  for general paging purposes. Alternatively, the transceivers attached to children may also be used to communicate with the children as a pager/buzzer or with voice messages. Most dining tables  26   a – 26   g  have only a single video station  28  located thereon, but some tables, such as tables  26   b  and  26   c , have two video stations  28  located thereon. As shown, table  26   b  has video stations  28   b &amp; c  located thereon, and table  26   c  has video stations  28   d &amp; e  located thereon. 
     Dining and entertainment facility  10  is accessed by the public via entrance/exit door  22  which leads into entrance foyer  11 . There are other emergency exit only doors (not shown) as may be required by municipal authorities. There may also be a door for deliveries and restricted access by employees only. There may be more than one public entrance/exit door, although only one such door is shown and described herein. A family or other group enters entrance foyer  11  and registers at reception desk  23 . As part of the registration process each family or group&#39;s picture is taken at photo desk  25  and an ultrasonic transceiver  34  is attached to each child with each family or group. For the purpose of this description, it is assumed that there are two children and they each respectively have an omni-directional, ultrasonic transceiver  34   a  and  34   b  attached to them. It may be attached to a child&#39;s wrist, ankle or elsewhere. The ultrasonic transceivers  34   a &amp; b  operate at the same frequency as ultrasonic receivers  29   a–r  that are described further in this description. For security purposes the transceivers  34   a &amp; b  are attached to the children in a manner that a child or anyone else cannot readily remove the transceiver. In addition, if a transceiver  34  is removed from a child in an unauthorized manner an alarm signal is immediately sent to the central computer and security measures are immediately taken to locate the child and to assure that they do not leave dining and entertainment facility  10 . Also, if an ultrasonic transceiver  34  on a child ceases transmitting its periodic signal, this is immediately detected by the central computer (not shown) in equipment room  33  and security measures are immediately taken to locate the child and to assure that they do not leave dining and entertainment facility  10 . These measures include displaying at video station  28   j  at the front desk, a video station in office  20 , and selected other video stations  28 , the output of the video camera(s)  30  from which video images of the child were being obtained at the moment that a transceiver attached to the child ceases transmitting or is removed in an unauthorized manner. 
     The family or group is then assigned to one of tables  26   a – 26   g . For the purpose of this description, it is assumed that they are assigned to table  26   b . The identity of each child&#39;s ultrasonic transceiver  34 ( a  or  b ) and table  26   b  that has been assigned to the family or group are input to a central computer (not shown) in equipment room  33  from video station  28   j  at reception desk  23 . While all ultrasonic transceivers  34  operate at the same frequency, they each periodically generate a distinctive signal that is used in determining the location of each transceiver  34  within facility  10 , but each periodic transmission is followed by other information indicating alarm conditions such as a transceiver attachment strap being cut or broken. More particularly, the system operates in a time division multiplex (TDM) manner wherein each child&#39;s transceiver  34  transmits its identification signal in a unique time slot assigned to each transceiver  34 . There is no master clock to synchronize transceivers  34  with a clock in the central computer. Rather, a clock run by an oscillator in each transceiver  34  is set by the central computer just before the transceiver is attached to a child and the clock free runs until set again. The clock is accurate enough that while free running over several hours it maintains a close enough synchronization to a clock in the central computer and in a sensor processor associated with the ultrasonic sensors in each room so that each transceiver&#39;s periodic transmissions remain in their respective time slots. 
     As part of the registration process the children may be authorized to play video games in video game room  15 . An automated system is used to implement access to video games. On initial registration at reception desk  23 , or at any time thereafter, a child is authorized to play a given number of times (game credits) on the games in video game play area  15 . This information and the fact that the child is authorized to enter game area  15  are stored in the central computer. A child&#39;s transceiver  34  is first used to gain access to video game play area  15  as previously described. A transceiver  34  is then used to play ones of video games  32 . To do so a child passes their transceiver  34  before an ultrasonic sensor on each of games  32 . This is sensed by the central computer and the particular game  32  is enabled to be played by the child, if the child is authorized to play the game  32  and they have remaining game credits. On the screen of the particular video game  32  the number of remaining game credits and the child&#39;s game winnings may be displayed. Each time a child plays a video game  32 , their remaining number of game credits is decremented in a debit card type operation. At any time during a visit to facility  10 , or upon leaving, a child may go to prize redemption center  21  and pick one or more prizes depending on the amount of their winnings at games  32 . 
     Dining area  12  and play areas  13 ,  14  &amp;  15  are accessed via a single entrance/exit gate  24  in entrance foyer  11  as shown herein, but more than controlled access may be provided. This restricted or controlled access, continuously monitored by personnel of facility  10  at reception desk  23 , provides excellent security against a child attempting to walk out, or an unauthorized person attempting to remove a child from facility  10 . When any person attempts to leave facility  10  with a child, the electronic photograph taken at photo center  25  upon registration is retrieved on the screen of video station  28   j  for comparison purposes. If the person attempting to leave facility  10  with a child is not the person shown in the family or group photograph, entrance/exit gate  24  will be locked and not be opened until the matter is satisfactorily resolved. 
     If there are members of the family or group assigned to table  26   b  who will be arriving after initial registration, their names are given to the personnel at reception desk  23 . When the late arriving group or family member(s) enter and identify themselves to the reception personnel they stand in front of a video camera  30   k  in entrance foyer  11  and the reception personnel uses video station  28   j  to send their video picture to video stations  28   b &amp; c  at table  26   b . The reception personnel then communicate audibly with the group at table  26   b  for authorization to permit the late arriving person(s) to enter and join the group or family at table  26   b.    
     Using touch screen video stations  28   b &amp; c  the family or group peruses the food and drink menu by touching the area of the screen that requests the display of the menu. When a menu is displayed, dining and drink selections are made by touching the screen on either of the two video stations  28   b  and  28   c . The menu may include pictures of the offerings, and may include a child menu and an adult menu. If there are questions about food or drink items, or requests for special preparation, an appropriate touch screen location may be touched to establish a video and voice connection with kitchen personnel as is described in detail further in this detailed description. 
     After all dining and drink selections are made, as displayed in an order column on the screen of video stations  28   b &amp; c , and including a current billing total, pressing an on-screen button entitled “Order” causes the order to be transmitted via the central computer (not shown) in equipment room  33  to be displayed on video station  28   k  in kitchen  18  along with the identity of table  26   b . Kitchen personnel watch monitor  28   k  and prepare food and drinks to fulfill the order for tables  26   a–g . After orders are prepared they can either be delivered to tables by facility personnel or, with self service operation, a visual and/or audio notice can be sent to video stations  28   b &amp; c  at table  26   b  that someone come pick up the order. Additional food and drink orders may be placed at any time during the course of the visit to facility  10 . 
     While waiting for a food and drink order to be delivered to table  26   b , or for a notice to pick it up, the two children wearing ultrasonic transceivers  34   a &amp; b  may remain at table  26   b , may walk around dining area  12 , play in any of play areas  13 , 14  and  15 , or go to bathrooms  16  or  17 . If a child remains at table  26   b  the periodic ultrasonic signal transmitted by their transceiver  34   a  or  34   b  is received by at least three of the ultrasonic receivers  29   b,c,d,e,f,g  positioned around the periphery of dining area  12  and is forwarded to a sensor processor (not shown) associated with each sensor. The sensor processor is described with reference to  FIG. 2 . The sensor processors measure the relative arrival times of the ultrasonic signals from transceivers  34   a  and  34   b  at receivers  29   b,c,d,e,f,g  to locate the exact position of these transceivers in dining area  12  in a manner well known in the art. While only two transceivers  34   a &amp; b  are mentioned in this description for the sake of simplicity, it should be understood that there could be thirty or more children, each having an attached transceiver  34 , inside dining and child entertainment facility  10 . Video stations  28   a–i  may also be used to play video games stored therein or in the central computer. This is particularly useful for smaller children who are not allowed to roam around facility  10 . Games, menus, pictures, etc, may all be accessed on video stations  28  with a windowing operation. 
     If a child goes to bathroom  16  or  17 , their presence in the bathroom is detected respectively by sensor  29   s  or sensor  29   r  therein, but because there are no video cameras  30  in the bathrooms, no video signal of the interior of the bathroom is forwarded to video stations  28   b &amp; c  at table  26   b  when a viewing request is made by the parent(s) using one of video stations  28   b &amp; c . Instead, a picture of the bathroom door is displayed on video stations  28   b &amp; c  and a message is superimposed thereon indicating the child&#39;s name and the length of time the child has been in the bathroom. The system software can keep track of the time that a child has been in bathroom  16  or  17  and provide an indication of same to their parents or chaperones at table  26   b  so they may determine if too much time has elapsed indicating that the child may be sick or in other difficulty and they can go check on the child. 
     The presence of a child in play area  13  is detected by sensors  29   i,j &amp; k ; their presence in play area  14  is detected by sensors  29   l,m &amp; n ; and their presence in video game play area  15  is detected by sensors  29   o,p,q . The sensor processors processes the signals received by the three sensors  29  in any of play areas  13 ,  14  and  15  or three sensors  29  in dining area  12  to triangulate and locate the exact position of the children wearing transceivers  34   a &amp; b  in a manner well-known in the art. The position of each child in facility  10  is stored in the central computer and is updated very frequently. The stored child location information is used to establish a viewing connection between requesting ones of the tables and the rooms in which particular children are located. A page/buzzer signal or a voice communication may also be sent directly to a child&#39;s transceiver  34  from the video station at the table where the child&#39;s parent(s), guardian(s) or chaperone(s) are located, or from video station  28   j  at reception desk  23 . 
     Entertainment in different ones of play areas  13 ,  15  and  15  may be chosen for given age groups. If it is decided to restrict access of certain children to particular play areas, electronically controlled doors, turnstile or other types of controlled access doors or gates  35  are added to the play areas  13 ,  14  and  15  that are controlled by ultrasonic sensors and the central computer. As previously mentioned a central attendant may also monitor and control access to play areas. Door  35   a  is added to play area  13 , door  35   b  is added to play area  14 , and door  35   c  is added to play area  15 . At the time of registration at reception desk  23  the registration personnel would use video station  28   j  to input child age information that would restrict what play areas a child may enter. For example, a young child may be allowed to enter play areas  13  and  14 , but not enter play area  15  wherein are located video games  32 . When a young child wearing ultrasonic transceiver  34   a  approaches door or gate  35   a  to play area  13  the signal from their transceiver is detected by a sensor at the door or gate, not shown, and is compared with access privileges stored in the central computer. Access may also be checked and controlled by the central attendant using a video display of the child. When the central computer determines that the child is allowed access to play area  13 , door or gate  35   a  opens. The same operation applies to play area  14 . However, when the same young child wearing ultrasonic transceiver  34   a  approaches door or gate  35   c  to video game play area  15 , the computer or attendant determines that the child is not allowed access to this play area and door or gate  35   c  remains closed. A turnstile type gate or other type of restricted access gate or door could be used that permits only a single child to enter at a time and thereby prevent a child having authorized entrance to a play area from letting in a child who does not have authorized access. 
     Older children who have been authorized access to video game play room  15  can enter and play the video games  32  therein based on their game play credits authorized on registration, or thereafter, and on the detection of their ultrasonic transceiver  34  by a sensor (not shown) at each particular video game  32 , with verification by the central computer. If the child has game winnings he or she may redeem them for prizes at redemption center  21  at any time or when departing facility  10 . When a child attempts to access a video game  32  their remaining game play credits and game winnings are displayed on the screen of the video game. 
     If a child walks into kitchen  18 , where they should not be, their presence is detected by sensor  29   h  that returns a signal to the central computer (not shown) in equipment room  33  that immediately recognizes that no coded ultrasonic signals from ultrasonic transceivers  34  worn by children should be detected in kitchen  18 . As a result the computer causes an audible alarm (not shown) to be given in kitchen  18  and kitchen employees or waiters/waitresses immediately locate the child and usher them from kitchen  18 . The kitchen employees and waiters and waitresses may also be equipped with a transceiver  34  to give them access to kitchen  18  or any other rooms, such as storage room  19 , office  20  and equipment room  33 . In addition, the central computer in equipment room  33  routes the video signal from video cameras  30   i  and/or  30   j  in kitchen  18  to video station  28   j  at reception  23  where personnel may view the presence of the child in kitchen  18 . Although not shown in  FIG. 1  a video station  28  may also be placed in office  20  to which the central computer also routes the video signal from video cameras  30   i  and/or  30   j  and someone in that office may view the presence of the child in kitchen  18  when the above mentioned alarm is sounded. Video station  28   k  is also used to receive food and drink orders, and to visually and orally communicate with video stations  28  on ones of tables  26   a–g , and to personnel at reception desk  23 . 
     While the parents of the children wearing ultrasonic transceivers  34   a &amp; b  are sitting at table  26   b  and their children are playing in the play rooms, the parents may view what the children are doing on video stations  28   b  and  28   c . This is done by touching an appropriate place on the touch screen operation equipped video display of station  28   b  and/or  28   c . This viewing request is transmitted to the central computer in equipment room  33 . Responsive to the viewing request the computer first identifies the table  26   b  from which the request originated, looks up where the children from table  26   b  are presently located and operates a video switch (shown in  FIG. 2  but not in  FIG. 1 ) that routes video signals from a selected video camera in the play area(s) in which the two children are located to video stations  28   b  and/or  28   c  at table  26   b . When there is more than one child, and a viewing request is made, the computer creates a split screen operation on video stations  28   b  and  28   c  and routes the video signal for each child to the video stations. Alternatively, two separate screens may be utilized and the parents may switch between the two screens. 
     For a specific example, when the parents at table  26   b  request to see their two children, the central computer has already detected ultrasonic transceiver  34   a  in play area  13  and ultrasonic transceiver  34   b  in play area  14 . From the triangulated position of the two children the central computer knows that one child is in the viewing area of video camera  30   e  in play area  13  and sends that video signal to table  26   b , and knows that the other child is in the viewing area of video camera  30   g  in play area  14  and sends that video signal to table  26   b . Using the touch screen operation of video stations  28   b  or  28   c  the parents can also request a close up of the children. The computer responds to this request and locates where in the previously identified video picture the child is located. The computer then performs a well known electronic zoom function and selects a smaller portion of the original video signals and expands them to thereby provide close up, zoom pictures of the children via the video signal switching equipment (not shown) in equipment room  33  to video stations  28   b &amp; c  at table  26   b.    
     A parent at table  26   b  may also audibly contact either or both their children. To accomplish this they touch an appropriate spot on either video station  28   b  or  28   c  at their assigned table  26   b  to request sending a page/buzzer signal to one or both of their child&#39;s transceivers  34   a  or  34   b , or to establish a voice communication link with either or both transceivers  34   a  and/or  34   b . To implement the page/buzzer operation low power radio frequency pager circuitry (not shown) located in equipment room  33 , alike that used in pager systems that are well known in the art, is provided to send coded page signal to selected ones of transceivers  34  where it is recognized and operates a pager signal also in a manner well known in the pager art. To implement the voice message operation a low power transmitter (not shown) located in equipment room  33 , also alike voice pagers that are well known in the art, is provided to send a coded address and voice message signal to selected ones of transceivers  34  where it is recognized and the voice message is played. In an alternative arrangement a short oral message can be sent to either or both of the child in playroom  13  via speaker  31   a , and the child in playroom  14  via speaker  31   b . For the alternative arrangement the central computer looks up play room  13  as the room in which the child wearing transceiver  34   a  is located, and play area  14  as the room in which the child wearing transceiver  34   b  is located and establishes an audio link between speaker  31   a  in playroom  13  and speaker  31   b  in playroom  14  and microphones located within video stations  28   b  and  28   b  at table  26   b . A message is then presented on screen to the parents to commence speaking to the child. A parent has a predetermined amount of time, say five or seven seconds to speak. In this manner, for example, the children may be called back to table  26   b  for dinner. 
     When the family finishes their stay in dining and entertainment facility  10  they may access their bill by touching an appropriate spot on video stations  28   b  or  28   c . They will then go to reception desk  23 , pay their bill and have the ultrasonic transceivers removed from their children. Alternatively, located on each table  26  is a card swipe mechanism (not shown) for using credit or debit cards to pay bills. As part of the check out process the children may at that time redeem their un-redeemed game win credits for prizes at redemption center  21 . Also as part of the check out process the personnel at reception desk  23  compare the photograph of the group or family taken on registration with the group leaving to assure that an unauthorized person or persons are not attempting to leave with a child or children. If this does happen exit gate  24  is locked and not opened, and the authorities may be called and/or the proper authorized persons paged to come to reception desk  23 . The gate opening operation is designed so that a button must be held down by personnel at reception desk  23  the entire time the gate is unlocked. If the button is released the gate immediately re-locks. This prevents an unauthorized person from pushing the button and attempting to exit through gate  24  before it re-locks. In addition, the unlocking button function may be replaced by a keypad (not shown) and the personnel at the reception desk must enter a code to unlock exit gate  24 . This operation would preclude an un-authorized person attempting to exit facility  10  with a child by jamming an exit release button. In addition, the un-authorized persons picture would be taken by a video camera. 
     In  FIG. 2  is shown a block diagram depicting a processor based system used to implement the present invention. Most of the operations of the security system shown in  FIG. 2  are controlled by the aforementioned central computer  36  that is located in equipment room  33  of  FIG. 1 . As previously described, there are a plurality of touch screen video stations  28  ( 28   a – 28   k ) positioned on dining tables  26   a – 26   g  in dining area  12 , at reception desk  23  ( 28   j ), office  20  (not shown), and kitchen  18  ( 28   k ). In  FIG. 2  the plurality of video stations are represented by two monitors designated  28   a  and  28   k  with a series of dots between them. In addition, there is a plurality of sensors  29   a – 29   q  shown in  FIG. 1  that are represented by two sensors designated  29   a  and  29   q  with a series of dots between them. Further, there is a plurality of video cameras  30   a – 30   j  shown in  FIG. 1  that are represented in  FIG. 2  by two video cameras  30   a  and  30   j  with a series of dots between them. Still further, there is a plurality of speakers  31   a – 31   h  shown in  FIG. 1  which are represented in  FIG. 2  by two speakers  31   a  and  31   h  with a series of dots between them. Finally, there is a plurality of games  32  in video game room  15  that are represented by two games Game  1  and Game N in  FIG. 2 . Games  32  are interconnected to central computer  36  via lead  51 . All these elements are interconnected and controlled by the central computer as will now be described. 
     Sensors  29  in  FIG. 2  are connected via a sensor interface  38  to a sensor processor  39  that processes the signals received from each child&#39;s ultrasonic transceiver  34  to first determine in which room a child is located, and then to triangulate the position of a child within a room. Ultrasonic signals are used instead of radio frequency signals because they will not pass through the walls in facility  10 . This technology is well known in the prior art and is based on measuring the relative arrival times of the signals from each ultrasonic transceiver  34  at each of the ultrasonic sensors  29  located in a room in which a child is located. Each ultrasonic transceiver  34  transmits a signal within an assigned time slot that thereby distinguishes it from other transceivers  34 . Sensor processor  39  is synchronized to the central computer clock so it can thereby determine which transceiver  34  a signal is received from. Sensor processor  39  forwards the identity and position information for each transceiver  34  via lead  47  to central computer  36  to be stored in memory  37 . An alarm condition signals sent from ones of transceivers  34  are also sent to the central computer for appropriate action to be taken. When each child has an ultrasonic transceiver  34  attached to them at reception desk  23  upon registration, a unique identity for that transceiver  34  was entered via video station  28   j  to central computer  36  along with the child&#39;s name and table assignment. Central computer  36  matches the transceiver identity and position information received from sensor processor  39  with the initially stored information and thereby knows at all times the location of each child within facility  10 . All this information is stored in memory  37 . 
     More particularly, the system operates in a time division multiplex (TDM) manner wherein each child&#39;s transceiver  34  transmits its identification signal in a unique time slot assigned to each transceiver  34 . There is no master clock to synchronize transceivers  34  with a clock in the central computer. Rather, a clock run by an oscillator in each transceiver  34  is set by the central computer just before the transceiver is attached to a child and the clock free runs until set again. The clock is accurate enough that while free running over several hours it maintains a close enough synchronization to a clock in the central computer and in a sensor processor associated with the ultrasonic sensors in each room so that each transceiver&#39;s periodic transmissions remain in their respective time slots. 
     Video cameras  30  are located throughout facility  10 , as shown in  FIG. 1 . As previously described a parent or other person located at an assigned table  26  can use the touch screen capability of the video station  28  at their table  26  to initiate a viewing request to show a picture of their child on video station  28 . The viewing request is forwarded to central computer  36  which looks up in memory  37  the room and specific location in the room the child of interest is located. This information was generated and stored as previously described. Using the location information central computer  36  identifies the video camera  30  in the room in which the child is located that will show the particular child. Computer  36  then sends a control signal via lead  48  to video switch  41  to switch the video output from the identified video camera  30  to the table  26  from which the viewing request originated. In addition, upon a request received from the particular table  26 , computer  36  may accomplish an electronic zoom on the portion of the video picture from the video camera in which the child is shown to provide a close-up picture of the particular child. 
     When a child is located in a bathroom  16  or  17 , in which there is no video camera  30 , when a viewing request is received by central computer  36 , a picture of the bathroom door is sent back to the video station  28  from where the viewing request originated. In addition, the name of the child and how long they have been in the bathroom are displayed on the screen with the picture of the bathroom door. If the parent, guardian or other responsible person thinks the child has been in the bathroom for an excessive length of time they may go check on them to make sure they are not sick or has other difficulties. Alternatively, if the central computer determines that a child has been in a bathroom more than a predetermined amount of time, an indication may automatically be sent to the child&#39;s assigned table. 
     Each video station  28  is comprised of a video display  42 , a microprocessor  43 , an audio portion  44 , and touch input circuitry  80 . Video display  42  is used to show video images sent from central computer  36 , such as menus, billing and other information, pictures from a video camera  30 , or video stations  28   j  or  28   k  forwarded via video switch  41 . Microprocessor  43  is used with all the functions including the touch screen operation of video station  28  and determines where a person is touching the screen as an indication of a request. These requests are forwarded via touch screen interface  45  and lead  49  to central computer  36  that processes the requests accordingly. In addition, microprocessor  43  can run games that are played on a video station  28 . 
     There are many types of requests and include, but are not limited to, menus, general facility information, food and drink ordering information, requests to see a picture of a child, and a request to send an oral message to a child. When a food and drink order has been prepared an Enter touch screen button is touched and the order is sent to central computer  36  which forwards the order to video station  28   k  in kitchen  18  were the order is prepared. If service staff is provided, when an order has been prepared they will deliver it to the particular table that placed the order. If no service staff is provided a visual and/or audible message is sent back to the video station  28  on the particular table that placed the order, and someone from that table picks up the food and drink order. 
     Audio portion  44  of each video station  28  serves two purposes. As described in the previous paragraph, if an audible message that a food and drink order is ready to be picked up is utilized, central computer  36  sends a control signal over lead  50  to audio switch  46  to forward the audible message to the audio portion  44  of the particular video station  28  from which the order was originated. 
     When a person at a particular video station  28  desires to send an audible message to a child, they touch an appropriate touch screen designation on video display  42 . Responsive thereto microprocessor  43  sends a signal via touch screen interface  45  lead  49  to central computer  36 . If the audible message (either page/buzzer or voice message) is sent to a transceiver  34  worn by a child the signal goes from audio switch  44  to central computer which causes a page signal or a short voice message signal to be forwarded over lead  78  to low power transmitters  79  which transmits their signals via antennas  80  to transceivers  34 . As previously described, the pager and voice signals each have a coded address signal that is recognized only by selected ones of transceivers  34  in a manner well known in the art. 
     If the signal is a voice message to be sent to a speaker  31  in the play area in which the child is located, computer  36  is responsive to the request for audible message by looking up in memory  37  the location of the particular child as previously described. A signal is then sent by central computer  36  via lead  50  to audio switch  46  to establish a path between audio portion  44  of the particular video station  28  and a speaker  31  in the room in which the particular child is located. While the audio communication path is established a message indicating same is placed on video display  42 . This audio connection is maintained for a short period such as five seconds, but this period may be longer or shorter. 
     This voice link capability may also be used when a food and drink order is being placed. When there are questions about food or drink items, or requests for special preparation, an appropriate touch screen location may be touched to establish a voice connection with kitchen personnel via video station  28   k . Responsive to the audio link request central computer  36  sends control signals via control lead  50  to audio switch to establish a voice link between the audio portion  44  of video station  28   k  in kitchen  18  and the audio portion  44  of the particular video station  28  requesting the voice connection. Voice communication then takes place over the link until the appropriate touch screen location on the video station in the kitchen or on the table is touched again to terminate the voice link. As previously mentioned a video connection may also be established. 
     This audio operation is also used by the facility personnel for general paging purposes, and to communicate with particular tables, such as when a late arriving person wishes to enter and join a family or group already seated. 
     Games  32  may be played using the game credits obtained at reception desk  23 , and game win credits are awarded by each game  32 . The game win credits are redeemed at any time, including on departure from facility  10 , for prizes at redemption center  21 . In this automated operation, games  32  may be interconnected to central computer  36  via lead  51 . As previously described, these games may be played by children who have been previously authorized to play same by receiving game credits. Sensors (not shown) are co-located with each game  32  and the presence of an ultrasonic transceiver  34  on a child standing in front of a machine and attempting to operate the game is detected. The identity of the ultrasonic transceiver  34  is returned to central computer  36  that checks for gaming authorization. If the child is authorized to play the game, and has remaining game credits, an enabling signal is returned to the particular game and the game is enabled to be played. In addition, the pre-authorized number of games credits is decremented, and win credits are accumulated by computer  36 . As previously described, upon registration, or thereafter, the child may receive a number game credits set by their parent, guardian or other to play a certain number of game plays, and each time the child plays any game it is deducted from their game credits. 
     When the family finishes their stay in dining and entertainment facility  10  they may access their bill by touching the appropriate spot on touch screen enabled video station  28   b  or  28   c . They will then go to reception desk  23 , pay their bill, redeem any prizes, and have the ultrasonic transceivers removed from their children. Located on each table  26  and/or at reception desk  23  may be a card swipe mechanism (not shown) for using credit or debit cards to pay bills. 
     As part of the checking out process the personnel at reception desk  23  compare the photograph of the group taken on registration with the group leaving to assure that an unauthorized person or persons are not attempting to leave with a child or children, and that all people are leaving. If this does happen exit gate  24  is locked, not opened and the authorities may be called and/or the proper authorized persons paged to come to reception desk  23 . The gate opening operation is designed so that a button must be held down by personnel at reception desk  23  the entire time the gate is unlocked. If the button is released the gate immediately re-locks. This prevents an unauthorized person from pushing the button and attempting to exit through gate  24  before it re-locks. 
     In  FIG. 3  is shown a flow chart of the program running on central computer  36  in  FIG. 2  to implement the preferred embodiment of the present invention. The program starts at block  52 . The first step in the operation is accomplished at block  53  where personnel at reception desk  23  enter information into the supervised child monitoring system using video station  28   j . The name of each member of a group is entered, their assigned table number is entered, the identification number of the ultrasonic transceivers  34  attached to specific named children of the group is entered, access authorization to particular ones of play areas  13 ,  14  and  15  is entered for specific ones of the children of the group, and game credits indicating the number of games that each child may play in video game play area  15  is entered. 
     At block  54  the program stores child location information received from ultrasonic sensor processor  39 . The location information is determined by a sensor processor  39  from signals received from ultrasonic transceivers  29   a–s  as previously described with reference to  FIG. 2 , and the child location information is stored in memory  37  for use in operations as previously described. 
     At block  55  the program processes service requests sent from customer tables  26   a–g , reception desk  23  and kitchen  18  using video stations  28   a–k . These service requests include sending food and drink orders to kitchen  18 ; providing audio communications between tables  26   a–g  to play areas  13 ,  14  &amp;  15 , kitchen  18  and reception desk  23 ; providing video access to view children in play areas  13 ,  14  &amp;  15 ; and displaying cumulative billing information at video stations  28   a–j.    
     At block  56  the program processes access authorization requests. These access authorization requests are generated by a child wearing an ultrasonic transceiver  34  walking up to the door or gate  35   a–c  of one of play areas where the distinctive ultrasonic identification signal generated by the child&#39;s ultrasonic transceiver  34  is detected by an ultrasonic receiver and sent to central computer  36  ( FIG. 2 ) located in equipment room  33  to determine if the child has been authorized by their parent or guardian to enter the play area. If authorization has been previously granted a signal is returned to the particular door or gate  35   a–c  to unlock the door or gate and permit the child access to the play area. If access has not been previously granted the door or gate  35   a–c  remains locked. 
     At block  57  the program processes video game  32  use information and adds it to the billing information for the group to which a child playing a game is a member. When a child wearing an ultrasonic transceiver  34  walks up to one of video games  32  in play area  15  to play same, the distinctive ultrasonic identification signal generated by their ultrasonic transceiver  34  is detected by a sensor at each game (not shown) and sent to central computer  36  ( FIG. 2 ) which keeps track that the child played the game and deducts it from their game credits previously authorized. With this automated game control operation, winnings earned at games  32  in play area  15  are collected by computer  36  and stored in memory with reference to the particular child who later may pick up their prizes at redemption center  21 . 
     At block  58  the program receives information from personnel at reception desk  23  using video station  28   j  to check out a departing family or group and provide final billing information for payment by cash or credit card. At this time ultrasonic transceivers  34  are removed from the children. Un-redeemed game winnings are read out of memory and the children may select their prizes at redemption center  21 . All information regarding the group is removed from central computer  36  in  FIG. 2 , except as may be saved for archive purposes. 
     In  FIG. 4  is shown a flow chart having more detail of block  55 , Process Requests From Tables flow chart shown in  FIG. 3 . Accordingly, the input to  FIG. 4  is from block  54  in  FIG. 3 , and the output from  FIG. 4  is to block  56  in  FIG. 3 . The first step in this flow chart is decision block  60  where the computer checks if food and drink ordering information is being sent from table  26   a –table  26   g . If the decision answer is yes, the order is retrieved from video station  28   a  on table  26   a  and forwarded to kitchen  18  at block  61  where the food and drink order is displayed on kitchen video station  28   k  for order fulfillment. The program then progresses to block  62  to update billing information for the group at table  26   a . If the decision answer is no, and/or after the billing information is updated, the program progresses to block  63  to process audio requests. 
     At decision block  63  the program causes central computer  36  to check if there is an audio request from table  26   a . This audio request may be implemented at table  26   a  if it is desired to talk with kitchen personnel about a food and drink order, to talk with children of the family or group assigned to table  26   a  who are playing in ones of play area  13 ,  14  &amp;  15 , and to talk to personnel at reception desk  23 . In the first instance the audio request is made at the time food and drink ordering information is being sent to kitchen  18 . In the second instance the audio request is made using a specific touch screen button indicating a request for an audio link to a child. In the third instance the audio request is made using a specific touch screen button indicating a request for an audio link to reception desk  23 . When the decision made at block  63  is yes, the program progresses to block  64  where the audio request is processed to establish the requested audio link. The steps performed in block  64  are described in greater detail with reference to  FIG. 5 . After an audio request is fulfilled, the program progresses to block  65 . If the decision at block  63  is no, the program also progresses to block  65  to check for a video viewing request from table  26   a.    
     Block  65  is a decision block whereat central computer  36  in  FIG. 2  checks to determine if there is a video viewing request from table  26   a  (table X). When the answer is yes, central computer  36  progresses to block  66  where the program running in the central computer processes the video viewing request to establish the requested video link. The steps performed in block  66  are described in greater detail with reference to  FIG. 5 . After the video request has been fulfilled at block  66 , or if the decision at block  65  is no, the program progresses to block  67  to determine if there is a request for billing information from table  26   a.    
     Block  67  is a decision block whereat central computer  36  in  FIG. 2  checks to determine if there is a request from table  26 a for cumulative billing information. When the decision answer is yes, the program progresses to block  68  whereat central computer  36  retrieves the cumulative billing information for table  26   a  from memory  37  and forwards it to be displayed on video station  28   a  at table  26   a . After the billing information is displayed, or if the decision answer is no, the program progresses to block  69  where the table number X is incremented and the next table, table  26   b , is indicated and processed as described in the previous paragraphs. 
     The program then progresses to decision block  70  where it is determined if all tables have been processed. If the decision answer is no, the program loops back to block  60  to repeat the above described operations, but now for table  26   b . This loop back repeats through the tables until the last table  26   g  has been processed. At that time the output from decision block  70  is yes and the program progresses to block  56  in  FIG. 3  to process access authorization requests. 
     In  FIG. 5  is shown a flow chart having more detail of block  64  in  FIG. 4 . Block  64  processes audio requests as previously mentioned. The first step in block  64  is decision block  59  whereat it is first determined if the audio request is to talk to a child. If the decision answer is yes, the program progresses to block  71  where computer  36  looks up from memory  37  the physical location in facility  10  of each child assigned to table  26   a . The child location information is required when an audio link is being requested to a child. When the decision answer is no, or after child location information has been read out of memory  37 , the program progresses to block  72  where control signals are sent to audio switch  46  by computer  36  to establish an audio communication link between table  26   a  and the requested location, or the location where a child is at. If the requested location is reception desk  23 , the audio link is established thereto. If the audio link has been requested to kitchen  18 , the audio link is established to a speaker in the kitchen. If an audio link had been requested to a child, the computer uses the child location information to establish the audio link to the particular play area  13 ,  14  or  15 , to a bathroom  16  or  17 , or to a speaker within dining area  12  closest to the child. The audio link is left established for a short period, such as five seconds, to permit sending an audio message to the child, and at block  73  the audio link is then disconnected. The program then returns to block  65  in  FIG. 4 . If the audible connection to a child is not via a speaker in a play area, the communication is transmitted to the transceiver  34  worn by a child. 
     In  FIG. 6  is shown a flow chart having more detail of block  66  in  FIG. 4 . Block  66  processes video viewing requests as previously mentioned. The first step at block  74  is to look up the location of the children assigned to table  26   a  by reading out the child location information stored in memory  37 . Using this information central computer  36  in  FIG. 2  sends a control signal to video switch  41  to establish a video link connection between video station  28   a  on table  26   a  and a video camera  30  located nearest to each child and which shows the child. If the first child, wearing ultrasonic transceiver  34   a , is in play area  13 , as shown in  FIG. 1 , and the video signal from video camera  30   e  is connected to video station  28   a  on table  26   a . The second child, wearing ultrasonic transceiver  34   b , is in play area  14 , as shown in  FIG. 1 , and the video signal from video camera  30   g  is connected to video station  28   a  on table  26   a . As previously mentioned, when there is more than one child in the group the computer will create a screen operation on video station  28   a  in a manner well known in the video art. Alternatively, ones of the split screens may be selected and displayed as full screen pictures. The program then progresses to block  67  in  FIG. 4 . 
     In  FIG. 7  is shown a side view of a room  84  and the angle of view of video cameras  30   j  and  30   k  within the room. The angle of view of camera  30   j  is shown as the two dashed lines from that camera, and the angle of view of camera  30   k  is shown as the two dash-dot lines from that camera. It can be seen that neither video camera  30   j  or  30   k  can provide an image of the entire room. For example, video camera  30   j  cannot image items below it, such as video game  85 , but video game  85  can be seen by camera  30   k . Also, video camera  30   k  cannot image items below it, such as door  81 , but door  81  can be seen by camera  30   j . Together cameras  30   j  and  30   k  can image the entire floor area  82  inside room  84  and, therefore, any child inside room  84  is in the view of one or both of cameras  30   j  and  30   k . For example, when a child is near door  81  video camera  30   j  is used to provide a video image of the child on the screen of video terminal  28  at the table to which the child is assigned. Conversely, if the child is at video game  85  in room  84  shown in  FIG. 7 , video camera  30   k  is used to provide a video image of the child on the screen of video terminal  28  at the table to which the child is assigned. In some instances more than two video cameras  30  may be required to provide images of all portion of a room. 
       FIG. 8  shows the video image output from video camera  30   j  and  FIG. 9  shows the video image output from video camera  30   k . More particularly, camera  30   j  has door  81  within its view as seen in  FIG. 7 , and the door  81  is seen in the video image in  FIG. 8 . Similarly, camera  30   k  has game  85  within its view as seen in  FIG. 7 , and the game is seen in the video image in  FIG. 9 . Together cameras  30   j  and  30   k  can image the entire floor area  82  inside room  84  and all items and people in the room. 
     It is necessary to calibrate the ultrasonic signal processing equipment (not shown) in equipment room  35  ( FIG. 1 ) using the video cameras  30  and the ultrasonic receivers  29  in each room (not shown in  FIGS. 7 ,  8  &amp;  9 ). This done by mapping the view of all cameras  30  in a room with physical locations in the same room as determined by the ultrasonic signal processing equipment checking physical coordinates of ultrasonic transmitters in the room. This is done in order for: (1) the system to determine which video cameras  30  in a room a child is in view of, and (2) to determine which video camera  30  in a room should be used to show a video picture of a child and which camera should be used when electronic zoom is to be accomplished. To perform this calibration one person sits at a touch screen equipped video station  28  while another person is inside a room that is to be calibrated. The two people are in voice communication with each other during the calibration process. The person inside room  84  has a rod about 2 feet tall with an ultrasonic transceiver  34  affixed to the top. This is shown as calibration tool  86  in both  FIGS. 8 and 9 . Tool  86  is meant to simulate a child wearing a waist mounted transceiver  34  playing inside room  84 . Although not shown in  FIGS. 8 &amp; 9 , room  84  would contain recreational equipment to be enjoyed by children playing in the room. 
     With reference to  FIG. 8 , the person inside room  84  with calibration tool  86  first stands tool  86  in the corner nearest door  81  as shown at  86   a . The person at video station  28  touches the screen at the top of tool  86 . The touch screen circuitry provides a signal to the central computer (not shown) in equipment room  33  indicating the screen location of tool  86 . At the same time there is a signal output from the ultrasonic sensor signal processor (not shown) that processes ultrasonic signals received from the ultrasonic transceiver  34  on the top of tool  86  and provides physical location information to the central computer. In this manner there is a correlation of the physical location of a transceiver  34  to a position on the screen of video station  28 . 
     The person inside room  84  then moves to the furthest corner on the wall in which is door  81  and stands calibration tool  86  as shown at  86   b . The person at video station  28  again touches the screen at the top of tool  86 . The process described in the previous paragraph is repeated and the central computer again has a correlation of a transceiver  34  in this corner of room  84  to a position on the screen of video station  28 . 
     While in voice communication with the person at video station  28 , the person in room  84  moves along the wall toward the video camera (not shown in  FIG. 8 ) until they are at the edge of the video screen as shown with the tool at  86   c . The above correlation process is repeated and stored by the central computer. The person in the room then moves to the opposite wall and, while in voice communication with the person at video station  28 , moves along the wall toward the video camera until they are again at the edge of the video screen as shown with the tool at  86   d . The above described correlation processes is repeated and stored. The person in room  84  then moves to the middle of the room to stand the tool at  86   e  when they are at the bottom edge of the video station screen. The above described correlation process is again repeated and stored. 
     Video camera  30   k  that generates the image in  FIG. 9  must then be calibrated in the same manner as just described with reference to  FIG. 8 . While in voice communication with the person at video station  28 , the person in room  84  places calibration tool  86  at positions  86   f ,  86   g ,  86   h ,  86   i , and  86   j  while the person at the video station  28  touches the screen for each position. 
     The above described process must be repeated with the zoom settings of each camera at different settings. This must be done because the ultrasonic signal processing equipment (not shown) in equipment room  35  ( FIG. 1 ) will have different mappings of physical three dimensional coordinates in a room with video screen locations for different camera zoom settings. 
     With this calibration process completed, when a child wearing an ultrasonic transceiver is in room  84 , or in any other room in which calibration has been accomplished, the central computer receives location information for the child from the ultrasonic sensor signal processor and can thereby first determine which of cameras  30   j  and  30   k  the child is in view of, or best in view of, and can then determine where in a video image output from the selected camera the child is located. This latter information is necessary when a close-up of the child is being generated by an electronic zoom process that is well known to the art. The computer uses the stored correlation information and interpolates where in the video picture from the chosen video camera  30  the child is located. 
     While what has been hereinabove is the preferred embodiment of the invention, it will understood by those skilled in the art that numerous changes may be made without departing from the spirit and scope of the invention. For one example, a small transmitter may be attached to each item in a warehouse and the signal from the transmitter used to physically locate the associated items, or to sound an alarm and take other actions if items are removed from their assigned locations without previous authorization. Alternatively, a transmitter may be attached to personnel in a highly hazardous area or a high security area. A transceiver may used instead if it desired to send a signal to a specific transceiver to cause an audio signal to be generated that can be used in locating a specific item.