Abstract:
A system and method for reading multiple items bearing electronic tags, such as radio frequency identification (RFID) tags, disposed in a read zone wherein a correlation scheme/system, separate (e.g. non-RF) from the electronic reader, is provided for verifying that all the items in the read zone have been successfully read. Typically, the user/operator is then notified whether or not all the items detected by the verification system have been successfully read by the electronic reader.

Description:
RELATED APPLICATION DATA 
     This application claims priority to provisional application No. 60/848,143 filed Sep. 29, 2006 hereby incorporated by reference. 
    
    
     BACKGROUND 
     The field of the present disclosure relates to operating methods and techniques for systems employing electronic tags such as radio frequency identification (RFID) tags. In particular, methods and apparatus are described herein for improving and facilitating operation of electronic tag and RFID reading systems. 
     RFID technology uses electromagnetic energy as a medium through which to send information. Typically, RFID tags are affixed to various articles for allowing identification of items in a sales transaction or tracking movement of the articles through a business location. In a typical RFID tag system, a receiver and some type of transmitter, an antenna, and memory are implemented. Through the use of these components, RFID tags are enabled to receive, store, and transmit article-identifying data to/from a remote data base station without the manual handling operations as is required in most bar code systems. 
     RFID tags may be read-only or read-write. Passive RFID tags may be implemented without an internal power source and draw their power from the radio frequency (RF) energy transmitted from the reader. Active RFID tags may include a power source such as a battery. RFID tags may be low or high frequency depending on the applications. 
     Existing RFID systems do not provide feedback to the user of an RFID reader to indicate whether or not the reader has effectively read each of the items. The present inventors have recognized that it may be advantageous for a user to receive feedback/verification that all items in the read zone have been effectively read by the RFID reader. 
     SUMMARY 
     Various embodiments described herein are directed to operation and feedback of systems combining an electronic tag reader (e.g., a Radio Frequency Identification “RFID” reader) with a weigh scale and/or an optical reader to verify reading operations for the electronic tag reader. In one embodiment, an RFID reader is combined with a weigh scale whereby input from the weigh scale is used to verify item identification by measuring a total weight of all the items (i.e. one or more items) on the weigh scale. The RFID reader obtains information from tags on each of the items in the read zone. The system then obtains item weight either via (1) using the item identification from the RFID tag and obtaining weight from a lookup table such as through the POS, or (2) extracting weight data stored in the RFID tag data itself. A total “calculated” weight is determined by adding the weights of all the items read by the RFID reader. The calculated weight is then compared to a “measured” weight of the items as measured by the weigh scale. If there is a discrepancy between the weights, then the operator may be notified to take further action. In another verification method, verification is provided by an imaging system that uses image recognition and/or optical code scanning to identify number of items. Upon completion of the RFID read operation, the number of items read by the RFID reader is compared to the number of items counted by the imaging system. If there is a discrepancy between the weights, then the operator may be notified to take further action. 
     Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an electronic tag reading system according to a first preferred embodiment for providing item read verification. 
         FIG. 2  is a diagram of an electronic tag reading system according to a second embodiment employing a handheld reader. 
         FIG. 3  is a diagram of an electronic tag reading system according to a third embodiment employing an alternate reader configuration. 
         FIG. 4  is a diagram of an electronic tag reading system according to a fourth embodiment employing a imaging scanner for item read verification. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Preferred embodiments will now be described with reference to the drawings. For the purposes of the present disclosure, certain of the descriptions will be described with respect to an RFID reader reading RFID tags, but the disclosure may also be applicable to other electronic tag types such as, for example, combined RFID/EAS tags, microwave tags, magnetic tags (e.g. acousto-magnetic), or other wireless electronic tag systems. The tag readers may comprise either electronic tag readers or combined electronic/RFID tag and optical code readers. 
       FIG. 1  illustrates a reading system  10  according to a first embodiment. Such a system may be applicable to various applications such as retail checkout, warehouse inventory, or parcel distribution. In the retail environment, the system  10  may be employed as a checker-assisted system or self-checkout such as at a grocery store or library. 
     The system  10  includes an RFID reader  16 , the reader  16  preferably including an integrated scale. A plurality of items is placed on the scale in the read zone. Reading operation is commenced and the respective tag on each item is read by the reader. The reader  16  employs a suitable protocol, such as query response protocol or air interface protocol (AIP), to read each of the tags sequentially without the need for the user to manually pass each of the items one at a time through the read volume. Read operation may be initiated via several schemes, for example: (1) a manual input from the user, such as by pressing a “start scan” button on a control display screen  15  at the operator terminal  14 ; (2) an activation signal from the scale that items are present in the read zone; (3) an optical wakeup sensor indicating that items are present in the read zone. The RFID reader  16  obtains information from a tag on each item in the read zone and transmits the information to the operator terminal  14 . At approximately the same time, the scale obtains a “measured” weight measuring a total weight of all the items (i.e. one or more items) on the weigh scale. The system, via a controller  12  (either at the terminal  14  or remotely) then obtains item weight either via (1) using the item identification from the RFID tag and obtaining weight from a lookup table such as through the POS, or (2) extracting weight data stored in the RFID tag data itself. A total “calculated” weight is determined by adding the weights of all the items read by the RFID reader. The calculated weight is then compared to the measured weight of the items as measured by the weigh scale. If there is a discrepancy between the weights, then the operator may be notified to take further action via a signal at the operator terminal. In the case of a retail self-checkout, both the customer-operator terminal and the store employee terminal may be provided with the further action notification. 
       FIG. 2  illustrates an alternate system  20  employing a handheld portable data terminal (PDT)  21 . The PDT  21  includes a keypad  22 , display (or touch) screen  23 , handle section  24  and a reader section  25 . The operator may manually sweep the reader  21  over a plurality of parcels  26  disposed on a scale  27 . The reader  21  then attempts to read the RFID tag disposed on each item. Meanwhile the scale  27  measures a total weight of all the parcels  26  (the measured weight) and sends this weight information to the controller  28 . Similarly to the previous embodiment, the system then compares the calculated weight of the items read by the reader to the measured weight of the items as measured by the weigh scale. If there is a discrepancy between the weights, then the operator may be notified to take further action via a suitable signal such as an audio signal from the PDT  21  or a visual signal on the display screen  23  of the PDT  21 . Read operation may be activated in response to a trigger pull on the handheld PDT or via another suitable protocol/mechanism. 
     In another configuration, particularly suited to the retail environment such as a grocery store, the user/operator or customer gathers items in a collection unit, such as a shopping cart, portable basket or bag, and proceeds to checkout.  FIG. 3  is a diagram of an alternate checkout system  30 . The shopping cart  36  (or shopping basket) containing a plurality of items/parcels  38  is placed onto a scale  35 . The system  30  includes a reader  31  in this embodiment supported on a stand  34 , located proximate the scale  35 . The reader  31  includes a keypad  32  and display screen  33  for interacting with the user. The RFID reader  31  is preferably disposed so as to face the parcels  38  in the cart  36  from a desired direction. In the configuration in  FIG. 3 , the reader  31  faces in a downwardly direction to provide a direct line of site onto the parcels  38  without having to pass through the side of the cart as would be required if the reader were mounted in a sidewardly-facing direction. 
     The scale  35  measures a combined weight of the parcels  38  and cart  36 . The weight of the cart  36  is subtracted from the combined weight to obtain the measured weight of the parcels  38 . The weight of the cart  36  may be obtained by the system in several fashions. If all the carts are the same type and have the same weight, a standard weight may be used. If the customer may use a basket or a cart, or if there are several models of carts, each cart may be provided with an RFID tag itself and the reader  31  would read the tag on the cart while reading the tags on the parcels and obtain the cart weight from the tag or from a lookup table. The cart may be identified by an optical recognition device, or the user may input the information that a cart is on the scale via a user interface  32 / 33 . Read verification of the parcels may then proceed as in the previous embodiments. 
       FIG. 4  illustrates another embodiment of a system  40  including an RFID reader  46  for reading a plurality of items (four items A-D) in a read zone. As in the previous embodiments, the system  40  includes a non-RF verification, i.e. a verification that is separate or independent from the RFID reader  31 . The previous embodiments used a scale for verification, and the system  40  employs an imaging scanner  42  to provide a secondary item count or verification as a double-check to verify that the RFID reader has successfully read each of the RFID-tagged items in the read zone. The scanner  42  may employ image recognition software to identify specific items or merely provide an item count. In order to improve the scanner&#39;s ability to provide an accurate item count, the system  40  may be placed into an “image and learn” mode whereby an operator may train the system to recognize a single item out of a plurality of items in the read zone. Alternately, the system may also learn and/or cross-verify by comparing items read by the RFID reader  46  with items identified by the scanner  42 . 
     It should be appreciated that the scale or other separate non-RF detection apparatus may be incorporated with the RFID reader into a common housing or otherwise integrated together. Even if the non-RF detection apparatus and the RFID reader are integrated, the mechanism/method by which non-RF detection is effected is still separate/independent. The non-RF detection of the number of items allows for separate or independent verification of the number of items such that the number of items detected by the non-RF apparatus or method may be compared to the number of items identified/read by the RFID reader. 
     In the following example, it is assumed that the RFID reader detects and reads only three out of four items in the read zone, and the system then operates according to the following steps.
         The RFID reader  46  sending data (of the three tags successfully read) to the micro controller  44 .   The micro-controller  44  sending a command to the scanner  42  to obtain an image of the items in the read zone.   The scanner  42  taking an image of the items in the read zone.   The scanner  42  sending the image to the micro-controller  44 .   Software in the micro-controller “finding” items and identifying number and (optionally) type of items.   Comparing the number and type of items imaged to the RFID data for correlation.   If the RFID data correlates to the number of items (and type), sending the RFID data to the POS terminal  48 .   If the items do not correlate, the micro-controller  44  not sending the RFID data to the POS terminal  48 , and the micro-controller  44  sending a message to the POS terminal  48  to command the operator/cashier to manually pass each item through the read zone.       

     Alternately, in the event the items do not correlate, the micro-controller  44  may notify the operator to optically scan the items manually by presenting each item to the imaging scanner  42  to scan the bar code. In operation, the operator may not need to present each item. For example, after removing Item A and optically reading it with the scanner  42 , the system  40  could then be reactivated with the RFID reader  46  attempting to read all the remaining items in the read zone. Repeating the process, the reader  46  may attempt to read all the remaining three items and the imaging scanner attempt to detect the number of items. If the read and the scan correlate this time for the three items, the RFID data is sent to the POS terminal. 
     Similar alternate methodology may be implemented in any of the above embodiments. For example, if any of the systems of  FIGS. 1-4  fails to correlate, the operator may remove one or more items (the “removed items”) from the read zone and reinstitute read operation. If the items remaining in the read zone are successfully read by the RFID reader and correlated to the non-RF verification, those items may be deemed successfully read and then moved out of the read zone to a successful read area. The “removed items” are then returned to the read zone and are re-read by the RFID reader. Alternately, the RFID reader may also comprise an optical reader. For example the RFID reader  16  in  FIG. 1  may also include and optical laser scanner. The handheld reader  21  of  FIG. 2  may include both RFID reading capability and barcode reading capability such as the FALCON® 5500 Series RFID Mobile Computer available from PSC Inc., now known as Datalogic Mobile, Inc., of Eugene, Oreg. The system  30  of  FIG. 3  may include an optical reader downfacing from the reader  31 . Alternately, the system may be provided with a separate handheld optical reader, for example kept in a holster mounted to the side of the reader  31 , for reading the optical code on an item in the exceptions case. 
     Read operation by the RFID reader of any of the embodiments may be implemented via a suitable system that enables multiple tags to be read in a single operation. Various operation schemes are disclosed in U.S. patent application Ser. No. 11/230,365, Publication US2007/0063871, filed Sep. 19, 2005 or U.S. patent application Ser. No. 11/351,405, Publication US2006/0214773, filed Feb. 11, 2006, each application being hereby incorporated by reference. 
     Thus the present invention has been set forth in the form of its preferred embodiments. It is nevertheless intended that modifications to the disclosed methods and systems may be made by those skilled in the art without altering the inventive concepts set forth herein.