Abstract:
A security method for a self-service checkout system with radio frequency identification (RFID) capability. The security method includes the steps of obtaining cart identification information from an RFID label attached to a cart by a security computer at a security station, obtaining first item identification information from a self-service computer transaction record using the cart identification information, obtaining second item identification information from a group of RFID labels attached to a group of items in the cart by the security computer, and comparing the first item identification information in the transaction record to the second item identification information to determine whether the second item identification information equals the first item identification information.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to self-service checkout systems in supermarkets and other retail establishments, and more specifically to a security method for a self-service checkout system with RFID capability. 
     Self-checkout systems typically include similar components as full-service checkout systems. One such self-service system is disclosed in U.S. Pat. No. 5,992,570 assigned to the assignee of the present invention. This patent is hereby incorporated by reference. 
     Self-checkout systems typically employ weight testing for security. Weight testing involves comparing the weight of a scanned item as determined in a look-up file against another weight reported by a security scale under a bag containing the item. Weight testing may also occur at the exit of a store. 
     Radio Frequency Identification (RFID) technology provides an alternative to bar code reader technology for distinguishing and recording items for purchase. Some of the uses of RFID technology are disclosed in U.S. Pat. No. 6,019,394 assigned to the assignee of the present invention. An example use of RFID technology in a self-checkout environment is disclosed in U.S. Pat. No. 6,547,040. These patents are hereby incorporated by reference. 
     It would be desirable to provide a security method for a self-service checkout system with RFID capability. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a security method for a self-service checkout system with radio frequency identification (RFID) capability is provided. 
     The security method includes the steps of obtaining cart identification information from an RFID label attached to a cart by a security computer at a security station, obtaining first item identification information from a self-service computer transaction record using the cart identification information, obtaining second item identification information from a group of RFID labels attached to a group of items in the cart by the security computer, and comparing the first item identification information in the transaction record to the second item identification information to determine whether the second item identification information equals the first item identification information. 
     It is accordingly an object of the present invention to provide a security method for a self-service checkout system with RFID capability. 
     It is another object of the present invention to provide a security method which compares RFID label information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram of a transaction system with RFID capability; 
         FIG. 2  is a perspective view of one example implementation of a self-service checkout system with RFID capability; and 
         FIGS. 3A and 3B  form a flow diagram illustrating the security method. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , one embodiment of transaction system  10  includes self-service checkout counter  12 , RFID label  14 , transaction server  16 , and security computer  52 . 
     Self-service checkout counter  12  includes terminal  18 , input device  20 , display  22 , printer  24 , card reader  26 , cash dispenser  28 , cash acceptor  30 , label interrogator  32 , and scale  34 . 
     Terminal  18  controls operation of self-service checkout counter  12  and executes transaction software  36 . 
     Transaction software  36  obtains item identification information, determines prices, and processes payment. 
     Transaction software  36  also sends individual transaction records to transaction server  16  with corresponding cart identification information stored in cart RFID label  72 . 
     Input device  20  records customer selections. Input device  20  may be a touch screen or keyboard. 
     Display  22  displays program instructions to assist the customer through a transaction. Display  22  may be a liquid crystal display and may be combined with input device  20  as a touch screen. 
     Printer  24  prints transaction information on receipt paper. 
     Card reader  26  reads information from customer payment and identification cards. Card reader  24  may include a magnetic stripe reader or smart card reader or combination of both. 
     Cash dispenser  28  provides change and extra cash. 
     Cash acceptor  30  accepts cash payments. 
     Label interrogator  32  interrogates RFID label  14  to determine a product identification number for a product associated with RFID label  14 . Label interrogator  32  may include an RF transceiver. Label interrogator  32  may be located in several locations, depending upon the configuration of self-service checkout counter  12  and any corresponding security precautions. 
     RFID label  14  is an identification label. RFID label  14  may vary in size, depending upon product size, and may be visible or hidden when attached to a product. RFID label  14  may be removably or permanently attached to the product. RFID label  14  includes label communicator  38 . 
     RFID label  14  may be an active or passive label. Active RFID labels may include RFID memory  40  and battery  42 . Alternative power sources may be capacitive, inductive, or derive energy from radio waves. Label communicator  38  may include an RF transceiver. 
     Passive RFID labels use very little energy and may only include label communicator  38 . Label communicator  38  may include a reflective antenna, such as a conductive ink antenna, which has a frequency which is unique among RFID labels. 
     If active, label communicator  38  sends item identification information stored in RFID memory  40  to label interrogator  32  in self-service checkout counter  12 . If passive, label communicator  38  sends a unique signature which is compared to a table of item identifications to identify the associated product. 
     Memory  40  stores item identification information and may include a read-only memory (ROM). 
     Battery  42  provides power to label communicator  38 . 
     Label interrogator  32  also interrogates cart RFID label  72  to determine a cart identification number. Cart RFID label  72  is similar to item RFID label  14 . 
     Transaction server  16  receives item identification from terminal  18  and returns price and weight information from price look-up data file  44 . 
     Transaction server  16  also stores individual transaction records in checkout data file  50 . Transaction records are indexed by cart identification information stored in cart RFID label  72 . 
     Scale  34  determines weight of all products on scale  34  for security purposes. 
     Self-service checkout counter  12  may additionally include a barcode reader  46  to the extent that some items contain barcode labels instead of RFID labels  14 . 
     Security computer  52  is operated by a security attendant. Security computer  52  executes security software  54  which compares items in cart  70  ( FIG. 2 ) with items listed in the corresponding record of checkout data file. Security software  54  obtains identification information from RFID label  14  and cart RFID label  72  through exit label interrogator  56 . 
     Security software  54  may also obtain a cart weight through exit scale  58  and compare the cart weight to the sum of purchased item weights determined from PLU data file  44 , self-service checkout system  12 , or both. 
     Turning now to  FIG. 2 , an example embodiment of self-checkout counter  12  is illustrated in detail. 
     Self-checkout counter  12  additionally includes counter  48 , camera  66 , and produce scale  68 . Counter  48  includes working surfaces  60 , which provide space for arranging or bagging purchased items from cart  70 . As such, working surfaces  60  include bag well  62 . 
     Label interrogator  36  is preferably located near any working surface  60 . In this embodiment, label interrogator  36  is shown in bag well  62 . Also, one or more scales  34  are envisioned and they may be located under any of working surfaces  60  to monitor for product substitutions. 
     Camera  66  monitors customers during checkout. A store employee may monitor several self-service checkout counters  12  from a security desk. 
     Produce scale  68  provides weight information for produce items, if purchased. 
     Referring now to  FIGS. 3A and 3B , a security method is illustrated in detail beginning with START  80 . 
     In step  82 , transaction software  36  waits for a customer. 
     In step  84 , transaction software  36  causes label interrogator  32  to obtain cart identification information from cart RFID label  72 . 
     In step  86 , transaction software  36  causes label interrogator  32  to obtain item identification information from each item labelled with an RFID label  14  in cart  70 . 
     In step  88 , transaction software  36  stores the cart identification information and the item identification information in a record in checkout data file  50 . 
     In step  90 , security software  54  causes exit label interrogator  56  to obtain cart identification information from cart RFID label  72 . 
     In step  92 , security software  54  reads checkout data file  50  to determine whether the cart identification information is stored therein. If so, operation proceeds to step  94 . Otherwise, operation proceeds to step  100 . In step  94 , security software  54  causes exit label interrogator  56  to obtain item identification information from each item labelled with an RFID label  14  in cart  70 . 
     In step  96 , security software  54  compares each piece of item identification information with item identification stored in checkout data file  50 . 
     In step  98 , security software  54  determines whether there is a discrepancy from the comparison. Specifically, security software  54  determines whether an item in cart  70  with an RFID label  14  is not in checkout data file  50 . This would imply that the item was not paid for at self-service checkout counter  12 . If so, operation proceeds to step  100 . Otherwise, operation proceeds to step  102 . 
     In step  100 , security software  54  notifies the security operator of the discrepancy. Security software  54  may display the status of the comparison. The security operator may cause exit label interrogator  56  to reread all of the RFID labels  14 . The security operator may also do a visual comparison of the items to a list of purchased items. 
     In step  102 , security software  54  optionally notifies the security operator that cart  70  has successfully passed inspection. Security software  54  may display the status of the comparison by displaying swapped or added items. Alternatively, security software  54  may provide no notification if there are no discrepancies. 
     Operation returns to step  82  to await the next customer. 
     Security software  54  may also do a weight check by having exit scale  58  weigh cart  72  and its contents and comparing the weight to a calculated weight. 
     Although the present invention has been described with particular reference to certain preferred embodiments thereof, variations and modifications of the present invention can be effected within the spirit and scope of the following claims.