Abstract:
A method for preventing the egress of a protected person (child) from a given region without an approved escort provides each child with an identifying RFID tag, and each approved person with an identifying RFID tag. A lock region is defined and scanned by a computer-based system which compares the RFID tag of the child within the lock region with a list of approved escorts, and maintains the lock region closed unless the child is accompanied by one of the approved escorts.

Description:
FIELD OF THE INVENTION 
   This invention relates to methods for providing controls tending to prevent kidnapping or unauthorized removal of infants or children from a given location. 
   BACKGROUND OF THE INVENTION 
   Much attention has been paid of late to the problem of kidnapping or unauthorized removal of children from their schools. Many schools currently use a sign-in and/or a sign/out sheet to document the taking of children from the custody of the school, and may rely on memory to identify the persons who remove children. 
   There have been proposals to identify children by the use of radio-frequency identification (RFID) tags, but these may not meet the needs of infant and child caregivers. 
   Improved or alternative arrangements or methods for control of the release of children from a controlled environment is desired. 
   SUMMARY OF THE INVENTION 
   A method according to an aspect of the invention is for preventing a protected person, such as a minor child, from leaving a building unless accompanied by an approved companion for that protected person. The method comprises the steps of providing each protected person with a radio-frequency identification tag, and providing each approved companion with a radio-frequency identification tag. A lock region is provided between the interior of the building and the outside world. The lock region has a first door opening into the interior of the building and a second door opening to the outside world. According to an aspect of the invention, a computer control or arrangement is used to determine if the RFID tag of a protected person is within the lock region. The protected person is deemed to be within the lock region if his RFID tag is present. Using the computer, a determination is made as to whether the RFID tag of an approved companion associated with the protected person is also within the lock region. The approved companion is deemed to be within the lock region if his RFID tag is present. If a protected person is within the lock region without a person approved as to the protected person, the second door is maintained locked. 
   A particular mode of the method includes the step of, if the protected person is within the lock region with an approved companion as to the protected person, locking the first door and unlocking the second door. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a simplified perspective or isometric view, partially cut away, of a building with a lock region according to an aspect of the invention; and 
       FIG. 2  is a simplified logic flow chart or diagram illustrating a possible control method according to an aspect of the invention. 
       FIG. 3  is a schematic representation of first and second RFID tags for use by a protected person and a companion, respectively; 
   

   DESCRIPTION OF THE INVENTION 
   In  FIG. 1 , a protected building  10  defines protective peripheral walls  12   a ,  12   b ,  12   c , . . . which are assumed to prevent unwanted ingress and egress. An exterior door  14  provides access to the interior of building  10 . Door  14  has a controllable latch or lock  14   c , which is remotely controllable to allow locking of door  14  so that it cannot be opened. Exterior door  14  opens into a lock region designated generally as  16 , defined by a portion of exterior wall  12   a , and by further walls  18   a ,  18   b , and  18   c . A person entering lock region  16  may enter the main portion  20  of building  10  by way of an interior door  22 , the latch of which is controllable by way of a control unit  22   c.    
   The building  10  of  FIG. 1  is used by persons protected by the arrangement according to the invention. More particularly, if the protected persons are minors or children, or infirm, as for example patients suffering from Alzheimer&#39;s disease, it may be desirable to assure that they do not leave the premises unless accompanied by a responsible or approved person, such as a parent in the case of a minor child. 
   According to an aspect of the invention, minors or other protected persons are provided with individualized radio-frequency identification (RFID) tags, which are remotely readable and which serve to identify the tag bearer. Each approved companion person, such as a child or other approved relative or caregiver, is also provided with a suitable identifying RFID tag. 
   In  FIG. 1 , wall  18   c  of the lock region  16  is fitted with a radio-frequency scanner  30  suited to scanning those RFID tags which are within the lock region, and reporting the sensed information to a computer control arrangement illustrated as a block  32 . 
   Door  14  of  FIG. 1  is normally locked as to egress from lock region  16 . The presence of the RFID tag of a protected person within lock region  16  has no effect, and door  14  remains locked as to that protected person, preventing their egress. The sensed presence of the RFID tag of another person, without the presence of a protected person, causes the control arrangement  32  to unlock door  14 , so that the party can exit the building. The sensed presence of the RFID tag of a protected person with the presence of a third party who is not the approved companion is insufficient to unlock door  14 , so that the protected person cannot exit with the “unapproved” companion or third party. Only the presence of the RFID tag of a companion approved for the RFID tag of the protected person allows the door  14  to be unlocked for egress of the protected party. 
   The control may be arranged so that door  14  cannot be unlocked unless door  22  is closed, and likewise so that door  22  cannot be unlocked unless door  14  is closed. 
     FIG. 2  is a simplified flow chart or diagram of one form which the logic of control arrangement  32  can take. In  FIG. 2 , the logic starts at a START block  210 , and proceeds to a block  212 , which represents reading the RFID tags present within lock region  16 . The identities associated with the observed tags are evaluated in a decision block  214  to determine if any of them represent protected persons. If there are no protected persons within lock region  16 , the logic leaves decision block  214  by the NO output, and proceeds to a block  216 , which represents unlocking exterior door  14  so that the persons in lock region  16  can exit. From block  214 , the logic returns to block  212 , to again read the RFID tags within lock region  16 . On the other hand, if one or more protected persons is/are identified as being within lock region  16 , the logic leaves decision block  214  by way of the YES output, and proceeds to a block  218 , which represents entry into a memory preloaded with protected parties as addresses, and which produces a list of all the approved companions for that protected party. Block  218  thus represents the accessing of one or more approved companions for the protected parties within lock region  16 . The logic then flows to a further decision block  220  which, for each protected party within lock region  16 , iterates through the list of approved companions for that/those protected persons, and determines the presence or absence of an approved companion for each protected person. This may be termed “pairing.” The logic leaves decision block  220  by the YES output if there is an approved companion for each protected person within lock region  16 , and the logic can then return to logic block  216 , representing unlocking of door  14 . The logic returns from block  216  to block  212 , to again begin reading RFID tags. On the other hand, if a protected person is present in lock region  16  without an approved companion, the logic flows from the NO output of block  220  to a block  232  and back to block  212 . Block  232  represents notification that an improperly accompanied protected person is within the lock region, and that they should return through door  22  to obtain proper accompaniment. 
   Of course, the flow of the logic can be arranged to keep an electronic record of such matters as the time at which a protected person leaves, which approved party accompanied the protected person, and other matters. 
   A method according to an aspect of the invention is for preventing a protected person, such as a minor child, from leaving a building ( 10 ) unless accompanied by an approved companion for that protected person. The method comprises the steps of providing each protected person with a radio-frequency identification tag ( 310 ), and providing each approved companion with a radio-frequency identification tag ( 312 ). A lock region ( 16 ) is provided between the interior ( 20 ) of the building ( 10 ) and the outside world. The lock region ( 16 ) has a first door ( 22 ) opening into the interior ( 20 ) of the building ( 10 ) and a second door ( 14 ) opening to the outside world. According to an aspect of the invention, a computer control or arrangement ( 30 , 32 ) is used to determine if the RFID tag ( 310 ) of a protected person is within the lock region ( 16 ). The protected person is deemed to be within the lock region ( 16 ) if his RFID tag ( 310 ) is present. Using the computer ( 32 ), a determination is made as to whether the RFID tag ( 312 ) of an approved companion associated with the protected person is also within the lock region ( 16 ). The approved companion is deemed to be within the lock region ( 16 ) if his RFID tag ( 312 ) is present. If a protected person is within the lock region ( 16 ) without a person approved as to the protected person, the second door ( 14 ) is maintained locked. 
   A particular mode of the method includes the step of, if the protected person is within the lock region ( 16 ) with an approved companion as to the protected person, locking the first door ( 22 ) and unlocking the second door ( 14 ).