EP0526038B1 - Article removal control system - Google Patents

Description

Technical Field

The present invention relates to a system forcontrolling removal of a specifically identified articlefrom a facility by a specifically authorized user and, inparticular, discloses variations to the arrangementdisclosed in Australian Patent No. 607,642.

Background

Article inventory control (AIC) systems, in general,authorize, track, and control movement of a given articlewithin a facility by a given user. An example is alibrary circulation control system. In this case, a usercould identify himself or herself with an identificationcard containing magnetically or optically detectable data(e.g., a barcode). The articles, books in the collectionof the library, typically have a similar identifyinglabel. Usually a computerized user database containsidentification data on all registered patrons of thelibrary, and a similar article database containsidentification data on all books in the library. Whensomeone desires to remove a book from the library, thelibrary circulation control system will first verify thatthe person is an authorized patron of the library, i.e.,that the person is authorized to check out any book, orany of a particular class of books. The system will thenverify that the particular book may be removed from thelibrary, e.g., that is not "on reserve". If both theuser and the book are authorized by the system, the bookmay be removed, ("checked out") by that user. Thisauthorization is often a visual or audible signal tolibrary personnel. Additionally, but not required, thesystem can maintain data which correlates the specificuser with the specific books checked out, and may issuefine notices, usage reports, and the like.

To prevent unauthorized removal of articles by usersof facilities, electronic article surveillance (EAS)systems may also be employed. An electronic articlesurveillance system is defined as a system whichcomprises:

(1) a remotely interrogatable marker attached toa given article;

(2) means for interrogating and sensing the markerwithin an interrogation zone, thereby determiningpresence of the article; and

(3) means for preventing removal of the article bya user of the facility.

For the purposes of this invention, the term"removal" is understood to include the ability of theuser to gain access to an article, to move an articlefrom one point to another within a facility, to bring anarticle into a facility, or to remove an article from afacility. The last of these is a common use of EASsystems. However, an EAS system as defined above cancontrol, for example, the routing of articles from oneportion of a factory assembly line to another.

Many EAS systems employ a magnetically activateable"marker" attached to an article, with appropriate markerinterrogation and sensing apparatus located at one ormore locations in the facility. Typically, removal of anarticle is prevented by restricting movement of thearticle within or from the facility, as with a lockableexit gate. The gate is locked in response to an alarmsignal when a marker is detected within an interrogationzone located immediately before the exit. In the libraryexample used above, the marker may comprise a piece ofmagnetic material adapted to be inserted in the bookspine or attached inside the book cover.

Typically, EAS systems employ permanently orreversibly deactivatable markers and the apparatusassociated with them. Such markers are also known as"dual status" markers. Permanently deactivatable markers are preferred where it is appropriate in certain circumstances for an article to passthrough the interrogation zone without preventing removal. For example, in a retailstore, if an article of merchandise has been purchased in a particular department, themarker may be deactivated at that point so that an interrogation zone in anotherdepartment will not activate the marker. Reactivatable markers are appropriate, forexample, in libraries where patrons who check out a book for an extended period oftime may subsequently visit the library with that book during that period. In this case,the system should not prevent subsequent removal of the book until the book has beenreturned, the marker reactivated, and the book returned to circulation.

The deactivate/reactivate devices are designed for operation on a single markercontaining article of typically maximum dimensions. However, they will function alsoon a plurality of marker containing articles whose combined dimensions equal themaximum. The deactivate/reactivate device cannot distinguish between a single largeor multiple small marker containing articles.

Integration of the functions of the two systems described above into a singlesystem is known in the art. For example, U.S. Patent 3,665,449 (Elder et al.) atcolumn 15, lines 62-67 generally suggests that automated library checkout systems maybe, combined with EAS systems. More specifically related to the present invention,U.S. Patent 4,141,078 (Bridges, Jr. et al.) discloses an automated library circulationControl system which provides for patron identification via card reader, bookidentification via an optical reader, modification and interrogation of computer datafiles, an electromagnetic device for magnetizing and demagnetizing a magnetic strip ineach book, detection of unauthorized removal of books from the library, and otherfunctions.

Application of this type of integrated system may bedifficult, especially in libraries in which one or bothof the individual systems are in current operation. Forexample, some existing EAS systems cannot distinguishindividual markers, only whether a sensitized marker ispresent. Thus a single library might employ markerswhich are identical, even on different types of books inthe collection. The marker therefore may not alreadycontain coded inventory data which could identify thetype of article to which it is attached. A library withsuch an EAS system in place, but no computerizedinventory control system, would have to add a uniqueinventory control marker to each book.

Many libraries may already use a system of codedinventory marking, but as no industry standard exists asto the type, coding, construction or placement of thesemarkers, they can be expected in any size, or codingscheme and positioned in any orientation on either front,back or inside cover.

Each book generally must be uniquely identified,including the identification of multiple copies of asingle title, some of which may be in general circulationand one being on reserve.

Furthermore, present EAS systems generally are notdesigned to receive removal authorization signals fromAIC systems added later. Thus, for complete articleremoval control in such a facility, it is necessary tohave separate article inventory control and articlesurveillance systems, and usually a manual, laborintensive, connection between the two. In a library,such a connection might be a circulation clerk who,seeing a flashing light on the AIC system indicating bookremoval authorization, physically passes a book througha marker deactivation device of the EAS system. Anotherpossibility is for the circulation clerk to manuallybypass the removal prevention means, e.g., physicallypassing the book around the interrogation device and handing the book to the patron on the other side of thelockable gate. Since the patron would pass through theinterrogation zone without any marked books, the gatewould remain unlocked and thus allow the patron to exitthe library.

Summary of the Invention

In accordance with one aspect of the presentinvention there is disclosed a responder assemblycomprising:

a plurality of sensors,

means for creating an electromagnetic field withina zone of sensitivity associated with each said sensor,said field being adapted to energize one or moresensitized markers located within said zones whichthereby transpond energy for detection by one or more ofsaid sensors, and processing means connected to each saidsensor for providing a detection pattern corresponding todetection of responded energy from one or more of saidsensors, said pattern being processed to determinewhether none, one or more than one said markers ispresent within said zones.

Brief Description of the Drawings

A preferred embodiment of the present invention willnow be described with reference to the drawings in which:

Fig. 1 is a schematic block diagram of the preferredembodiment and associated components;

Fig. 2 is a schematic block diagram of a prior artarticle inventory control system;

Fig. 3 shows schematic block diagrams of componentsof Fig. 1;

Fig. 4 is a schematic block diagram of a typicalprior art AIC system controller;

Fig. 5 is a schematic block diagram of the PSCServer of Fig. 1;

Fig. 6 is a schematic block diagram of the PSCController of Fig. 1;

Fig. 7 is a perspective view of the PSC Server ofFig. 5 combined with the responder assembly of Fig. B.

Fig. 8 is a side elevation view of the responderassembly;

Fig. 9 is a side cut-away view of a preferredactivation unit for the desensitizer of Fig. 3;

Figs. 10A-D illustrate how various markerarrangements are detected.

Figs. 11A and 11B are front and side elevation viewsrespectively of part of the waveguide of Fig. 8; and

Figs. 12A to 12C show variations in the waveguidefor various other sensor configurations.

Detailed Description

Figs. 1-3 show the major components of the preferredembodiment of a Patron Self Check (PSC) system locatedwithin a portion of a facility generally indicated as100.

Within the facility is at least onearticle 110attached to which areArticle Identification Code 220 andan Electronic Article Surveillance (EAS)Marker 310. TheCode 220 could be a label, similar to a Universal ProductCode (UPC) label.

APSC Controller 200,Electronic ArticleSurveillance 300 andBook Check Unit 500 can exist withinthefacility 100 prior to the installation, or may beinstalled with at least onePSC Server Terminal 400.

Associated with thePSC Server 400 is one of moreUser Identification Cards 210. In general, each user(not shown) of thefacility 100 is identifiable throughthe User Identification Card, and eachArticle 110through the correspondingArticle Identification Code220. TheArticle Identification Code 220 generally ispermanently affixed to the article itself, embedded or inscribed on the article, or affixed to a tag adapted tobe attached to the article.

ThePSC Server 400 sends anActivation Signal 710 totheBook Check Unit 500 when anArticle Authorization 270is received from thePSC Controller 200 in the usualmanner.

ThePSC Server 400 also contains aPattern Generator253 which senses a pattern of theSensitized Markers 310.TheServer 400 also senses the presence of anArticle 110within a desensitizing area provided therein. It alsocontains user activated indication that the user isrequesting service from thePSC Server 400 by aUserActivating Device 263.

APSC Controller 200 is provided including aPSCLink 201 whereby information, from thePSC Server 400, asto User I.D. and Article I.D., is received onLines 232and 242 respectively. This information is then sent tothe customer's data base (not illustrated) onLine 233for confirmation that the transaction can proceed.

ThePSC Controller 200 also receives informationfrom thePSC Server 400 regarding a pattern of sensitizedmarkers that have been detected by thePattern Generator253. This pattern is received onLine 252 and from thepattern received, thePSC Controller 200 through thePSCLink 201, determines as to whether there is more than onesensitized marker present within the desensitizing area.

ThePSC Controller 200, throughPSC Link 201, alsoreceives information from thePSC Server 400 that anArticle 110 has been detected as being present in thedesensitizing area of theBook Check Unit 500 and thatthe user has requested action by the activation ofUserAction Device 263, onLines 272 and 292 respectively.

ThePSC Controller 200, throughPSC Link 201,receives confirmation from the customers data base onLine 233 that the check-out action can proceed and thendetermines from thePattern Generator 253 that only oneArticle 110 is present in the desensitizing area ofPattern Generator 253. This determination results in thePSC Controller 200, throughPSC Link 201, enablingLine270 to thePSC Server 400 to activate the ArticleRemovalAuthorization Function 710.

TheEAS System 300 interrogates theEAS Marker 310with anInterrogation Signal 322 and upon receipt of aVerified Removal Response 324 allows the user to removethearticle 110 from thefacility 100.

In this way communication between theseparatesystems 200, 300 and 500 is established. The result isthat theEAS System 300 permits a given article to beremoved from the facility only by a given authorizeduser, having ensured that only one article pertransaction has been authorized for removal.

The preferred embodiment utilizes existing PSCController signals in the integration of PSC and EASfunctions without requiring any modifications to the EASSystem or any hard-wiring between the two systems. Inorder to disclose this, additional informationdescription of the PSC and EAS systems is useful.

Fig. 2 is a schematic block diagram of a typicalprior art ArticleInventory Control System 2000 which canbe replaced by thePSC Controller 200 of Fig. 1. Asstated above, inputs to this system are the transmittedUser Identification Signal 232, and the transmittedArticle Identification Signal 242. The output from thesystem is the ArticleRemoval Authorization Signal 270.The transmittedUser Identification Signal 232 isevaluated by a User Identifier 2300 (e.g. a data base issearched), and a determination is made whether the useris known to the system. If so, a verifiedUserIdentification Signal 2340 is issued to anArticleRemoval Authorizer 2500. Similarly, the transmittedArticle Identification Signal 242 is evaluated by anArticle Identifier 2400 (e.g. another data base issearched), and a determination is made whether thearticle is known to the system. If so, anArticle Identification Signal 2440 is issued to theArticleRemoval Authorizer 2500. TheArticle Removal Authorizer2500 uses both verifiedIdentification Signals 2340 and2440 to decide if the user is authorized to remove thearticle from the facility. (Additional consideration, notshown, may include the time of day, number of previousremoval requests by a given user in a day, and the like).If so, an ArticleRemoval Authorization Signal 270 isproduced. If any of the evaluations, determinations,etc., above indicate an unauthorized user and/orunauthorized article the ArticleRemoval AuthorizationSignal 270 is not produced.

Fig. 3 is a schematic block diagram of a typicalElectronicArticle Surveillance System 300, and aBookCheck Unit 500. The EAS system, generally arranged at anexit of a library or retail store for example, sends anInterrogation Signal 322 to theEAS Marker 310 andreceives the sensedSignal 324 from theEAS Marker 310.Typically, theInterrogation Signal 322 results in analternating magnetic field of known intensity andfrequency in an interrogation zone. The sensedSignal324 is induced as a result of the alternatingmagnetization in themarker 310 in response to theInterrogation Signal 322, and comprises multipleharmonics of the interrogation signal. When an activatedEAS Marker 310 is interrogated and sensed by anInterrogator/Sensor 320, anActivation Status Signal 330is created. This signal is used by aRemoval Preventer350, such as a lockable gate for example, to decide ifthe article to which the activated marker is attached maybe removed from the facility.

The embodiment shown in Fig. 3 is suitable for usewith permanently deactivatable markers. Accordingly, theEAS System 300, further comprises a Deactivator 540 whichforms part of theBook Check Unit 500 and, which receivesthe verified ArticleRemoval Authorization Signal 710from theTerminal 400. Additionally the receipt ofSignal 710 energizes the deactivator 540, which in turnemitsDeactivation Signal 542 to themarker 310.Typically,Deactivation Signal 542 is a high intensitynon-alternating magnetic field. Once theMarker 310 ispermanently deactivated, the sensedSignal 324 is notproduced upon subsequent interrogation, and thus theActivation Status Signal 330 is as if no marker weresensed at all. Therefore, theRemoval Preventer 350 doesnot prevent the user to remove the article.

Generally, when the Deactivator 540 is not providedwith theAuthorization Signal 710, it outputs a lowenergy alternating magnetic field.

An alternative embodiment similar to the above issuitable for EAS Systems employing reactivatable markers.In this case, there is at least two signals received bythe EAS System from the terminal. One signal is theverified ArticleRemoval Authorization Signal 710, whichis used, for example, to allow a library user to removea book from the library upon "check out". Upon receiptof this signal, the system operates as described above,except the marker is only temporarily deactivated. Asecond signal (not shown ) energizes a reactivator (alsonot shown), which emits a suitable signal to restore atemporarily deactivated marker to active status. This isused, for example, to allow a library user to return abook to the library upon "check in".

Regardless of the type of marker chosen, removal ofarticles by users determined to be authorized by theArticle Inventory Control System is accomplished byrequiring an appropriateActivation Status Signal 330 asdescribed above.

Fig. 4 is a schematic of a typical prior art of anArticle Inventory Control (AIC)System Controller 4000which contains a device for the ultra-sonic widthmeasurement of anArticle 432. This width measurement isthen compared against a record of the article's widthwhich can either be contained in an extended Article Characteristic CodedLabel 442 attached to the article orcan be a record maintained on a data base which issearched as a part of the Authorized Article Removaloperation.

Integral to the successful operation of this art isthe required labelling of each article contained in afacility. This action may be in addition to a labellingfunction that has already occurred wherein the customerhas an existing quantity of articles that have alreadybeen labelled with theArticle Identifier 442.Alternatively, the successful operation of this artrequires creation of a data base which contains ameasurement of the width of an article and the linking ofthis measurement to that article. This may be inaddition to a data base which has already been created bythe customer to contain other details of the article.

TheTerminal Controller 4000 receives theUserIdentification Data 412, theArticle Identification Data422, theArticle Characteristic Measurement 432, theCodedArticle Characteristic Measurement 442, and theArticleRemoval Authorization Signal 270. The terminal4000 sends theUser Identification Signal 232, theArticle Identification Signal 242, and the verifiedArticleRemoval Authorization Signal 710. A user of thefacility who desires to remove an article from thefacility enters his or her user identification data intothe terminal. This can be done by typing anidentification number on an alpha-numeric keypad.

Similarly, the article identification data isentered into the terminal 4000, for example by using anoptical scanner to read a barcode on the article. AUserIdentification Receiver 4100 receives theUserIdentification Data 412 and sends an InternalUserIdentification Signal 4140 to theUser IdentificationTransmitter 5100. Similarly, anArticle IdentificationReceiver 4200 receives theArticle Identification Data422 and sends an InternalArticle Identification Signal 4240 to theArticle Identification Transmitter 5200.Either or both of these processes can involve atranslation of the input Signals 412 and 422 into adifferent encoding format, such as from ASCII to BCD.

TheUser Identification Transmitter 5100 receivesthe InternalUser Identification Signal 4140 and sendsthe transmittedUser Identification Signal 232 to theUser Identifier 320 of theAIC System 2000, describedabove (Fig. 2). Similarly, theArticle IdentificationTransmitter 5200 receives the InternalArticleIdentification Signal 4240 and sends the transmittedArticle Identification Signal 242 to theArticleIdentifier 2400, also in Fig. 2. Either or both of theseprocesses can involve a translation of the InternalSignals 4140 and 4240 into a different encoding format,such as ASCII to BCD. It is mandatory that the User andArticle Identification Signals 232 and 242 be compatiblein coding (e.g. ASCII) and form (e.g. audible tone,varying voltage level, etc.) to the signals which the AICSystem is designed to accept.

The article characteristic measurement is made by anArticle Characteristic Measurer 4300, which also producesa measured Article Characteristic Signal 434. The codedArticle Characteristic Receiver 4400 receives the codedArticle Characteristic Measurement 442 representing thesame characteristic, but the latter is coded in a formthat is not necessarily understandable to the user. Forexample, with a keypad as described above, the user mayenter an alpha-numeric or other code printed on alabel.attached to the article. Alternatively, if thecode is in the form of a barcode, or the like, it mayalso be automatically entered. The code gives the Valueof the characteristic as measured before the article wasmade available for removal from the facility. Inresponse, the terminal 4000 produces a codedArticleCharacteristic Signal 4440, and the measuredCharacteristic Verifier 4500 compares the measured and codedSignals 4340 and 4440 to verify that only theactual article 110, and not just a tag containing theArticle Identification Code 220 for example, is in factpresent at the terminal. This comparison produces aCharacteristic Verification Signal 4520, which is oneinput to anArticle Removal Enabler 7000. The use of averified measured characteristic of thearticle 110 ispreferred for its accuracy over non-measurement basedsystems such as that taught in U.S. Patent 4,141,078(Bridges, et al.), e.g. atcolumn 6, lines 6-14.

Another input to theArticle Removal Enabler 7000 isan Internal ArticleRemoval Authorization Signal 6140.This signal is produced by an ArticleRemovalAuthorization Receiver 6100, which receives the ArticleRemoval Authorization Signal 270 from theArticle RemovalAuthorizer 2500 of theAIC System 2000, of Fig. 2. Aswith the User andArticle Identification Transmitters5100 and 5200, the ArticleRemoval Authorization Receiver6100 can translate the ArticleRemoval AuthorizationSignal 270 into a different encoding format, such as fromASCII to BCD. It is likewise mandatory that the ArticleRemoval Authorization Receiver 6100 be capable ofreceiving and understanding the ArticleRemovalAuthorization Signal 270 which theAIC System 2000 isdesigned to emit, including encoding (e.g. ASCII) andform (flashing light, RS-232C, 20mA current loop, etc.).

TheArticle Removal Enabler 7000 performs a logical"AND" function, requiring bothSignals 4520 and 6240 tobe present before issuing the ArticleRemovalAuthorization Signal 710 to Deactivator 540 of the EASSystem 500 (Fig. 3). Thus, the issuance of theSignal710 identifies to theEAS System 500 that (1) the user isauthorized to remove thearticle 110 according to theArticleRemoval Authorization Signal 270, and (2) thearticle is in fact present at the terminal according tothe measuredCharacteristic Verification Signal 4520.

In certain applications, it may be convenient toremove theUser Identification Transmitter 5100 and/ortheArticle Identification Transmitter 5200 from theterminal 4000 and physically locate either or both neartheAIC System 2000. Similarly, theArticleAuthorization Receiver 6100 may be removed from theterminal 4000 and located near theEAS System 500.However, it is preferred to incorporate or duplicate thedeactivation and/or reactivation functions directly intotheterminal 4000. In this case, theArticleAuthorization Receiver 6100 is not removed from theTerminal 4000, and ArticleRemoval Authorization Signal710 is wholly internal to theTerminal 4000. However,theRemoval Preventer 350 would still stand alone andinclude a Duplicate Interrogator/Sensor 320 operating asdescribed above.

Fig. 5 is a schematic block diagram of thePSCServer Terminal 400 used in the preferred embodiment.The terminal 400 receivesUser Identification Data 412,andArticle Identification Data 422,Book Present Status245, User Action Requests 243, sensitizedArticleResponses 233 and ArticleRemoval Authorization Signal270. ThePSC Server Terminal 400 sends the decodedUserIdentification Signal 232, the decodedArticleIdentification Signal 242, the recognition pattern of thesensitizedArticle Detection 252, theBook Present Status272, the UserAction Request Status 292 and the verifiedArticleRemoval Authorization Signal 710.

Items 412 and 422 may, in some cases, be combinedand used to capture both the User I.D. and Article I.D.details. Consequently, in such cases aUserIdentification Receiver 410, connected toLine 412, andanArticle Identification Receiver 420 connected toLine422, can have their functions combined into a singledevice. Similarly, transmitteddata 232 and 242 can alsobe combined.

Anoptional keyboard 296 or touch screen monitor andreceipt printer 298 may also be present for the keying ofuser passwords and the receipting of ArticleAuthorization details.

A user of thefacility 100 who desires to use thefacility enters his or her User I.D.Card 210 into thedefined reading area. The User ActivatedDevice 243senses the presence of the User I.D. and signals to thePSC Controller 200 (Fig. 6) onLine 292.

ThePSC Controller 200 responds onLine 270 with aninstruction to turn on theOptical Scanner 299. Thescanned User I.D. 412 is received and decoded at 410.The data is transmitted to thePSC Controller 200 onLine232.

ThePSC Controller 200 may now ask for a password tobe entered on thekeyboard 296 or touch screen monitor.Keyboard data is transmitted to thePSC Controller 200 onLine 232.

Thearticle 110 to be authorized for removal is nowplaced in the desensitizing area 850, shown in Fig. 7.BookPresent Detectors 807 and 808 (Fig. 7) providesignal 245 which is detected by aBook Present Detector265. This action is signalled to thePSC Controller 200onLine 272.

ThePSC Controller 200 now signals to theOpticalScanner 299 viaLine 270 to activate, and scanned data isreceived onLine 412 or 422 and decoded indevices 410 or420 respectively. The decoded data is sent to thePSCController 200 onLines 232 or 242 respectively.

Internal processing within thePSC Controller 200,interacting with the data base viaLine 233 determinesthe further validity of authorizing the issue of thisarticle 110 to this user.

If the determination is that issue is approved, thePSC Server Terminal 400 is instructed to place thecontents of aPattern Generator 253 ontoTransmissionLines 252. ThePattern Generator 253 is connected to a Multi-Strip Responder Assembly 803 (seen in Figs. 7 and8) which, together with other devices (e.g. 410, 420,253) within thePSC Terminal 400, interconnect with acommon bus 405. ThePSC Controller 200 then makes afurther determination as to how many sensitized articlesare present in the desensitizing area 850. If thedetermination is that either one or none are present, thePSC Controller 200 issues the Article RemovalAuthorization Signal onLine 270. This action isdirected to the Book Check Unit viaLine 710. Some booksmay not contain anEAS Security Marker 310 and thereforewould register as no marker present.

If the determination is that there is more than onearticle present, an instruction is displayed on thePSCController 200 directing the user to obtain assistancefrom facility staff, and removal authorization isinhibited. Accordingly, the user is prevented fromremoving a plurality of articles where only one isrecorded as removed, as in the prior art arrangement.

Referring to Fig. 6, the functioning and timing ofthePSC Server 400 is controlled by a processor andprograms calledPSC Link 201 which resides in thePSCController 200.

ThePSC Controller 200 receives data from thePSCServer 400 such as the decoded User I.D. 232, the decodedArticle I.D. 242, thecontents 252 of thePatternGenerator 253, thestatus 272 of theBook PresentDetector 265, thestatus 292 of the User ActivateDevice263 and information from the data base viaLine 233. ThePSC Controller 200 sends information to activate theArticle RemovalAuthorization Signal Receiver 490 viaLine 270 and to the data base viaLine 233.

PSC Link 201 is a combination of hardware andsoftware which interfaces Receivers andTransmitters 602to theCommunications Port 603. The receivers andtransmitters accept and hold data conditions asdetermined by thePSC Link 201.

TheCommunications Port 603 allows for connection toa customers mainframe. This port can be one of severaltypes of Communication Port such as RS-232, Current Loop,3270 Emulation but is not limited to this group.

When thePSC Link 201 senses that Line 292 (UserActivate Device 263) has changed status, it causesLine270 to transmit an instruction to thePSC Server 400 toactivate abarcode reader 802, seen in Fig. 7.

Information returned from thePSC Server 400 onLine232 is verified byPSC Link 201 to conform to the formatof a User I.D. known to thefacility 100.

ThePSC Link 201 then causes this information to betransmitted to the user data base onLine 233 where it isverified that the user is known to the facility and thatthe user is in good stead with the facility and isauthorized to obtain articles from the facility.Alternatively, the data base determines that the user hashad his/her borrowing rights withdrawn.

ThePSC Link 201 receives pre-authorizationinstructions from the data base and visually indicates acourse of action to the user. If authorization is likelyto be granted, a visual indication is displayedinstructing the user to place an article for authorizedremoval into the desensitizing area 850. Ifauthorization has been withdrawn, thePSC Controller 200instructs the user to seek assistance from facilitystaff.

ThePSC Link 201 then monitorsLine 272 for a changein state and upon detecting this action signals to thePSC Server 400 viaLine 270 to activate abarcode reader802. Information returned from thePSC Server 400 onLine 232 or 242 is verified byPSC Link 201 to conform tothe format of article I.D.'s known to his facility.

ThePSC Link 201 then causes this information to betransmitted to the customers data base onLine 233 whereit is verified that this article I.D. is known to the data base and that thisarticle 110 does not have anyprohibitions on its issue status.

Alternatively, a determination is made that thisarticle 110 cannot be issued at this time.

If the article has been released for authorizedissue thePSC Link 201 receives the contents of thePattern Generator 253 fromLine 252 and makes adetermination as to the number of sensitized articlesthat are present in the desensitizing area 850. If thisnumber is zero or one it issues the Article RemovalAuthorization Signal onLine 270, communicates with thedata base onLine 233 to indicate the RemovalAuthorization on the current transaction has occurred andindicates by visual display to the user the options ofhis/her next action.

Alternatively, if the determination is that morethan one sensitized article resides in the desensitizingarea of thePSC Server 400, the Article RemovalAuthorization is not sent, thePSC Controller 200communicates with the data base onLine 233 to cancel thecurrent transaction and indicates by visual display tothe user to seek assistance from facility staff.

ThePSC Link 201 then monitorsLine 272 and 292 fora change in state from which a determination is made thatthe user has removed his/her I.D.Card 210 in which casethe session is terminated, or that an article has beenremoved and replaced with another indicating that thereis a further Article Removal Authorization issue tooccur.

Fig. 7 shows a preferred embodiment of the PSCServer Terminal chassis 800, which incorporates thePSCServer 400, on top of which is mounted aVisual DisplayUnit 801 portion of aPersonal Computer 604 included inthePSC Controller 200. The remaining functions of thePSC Controller 200 can also be incorporated within thechassis 800. The embodiment of Fig. 7 includes thepreferred configuration discussed above in which certain deactivation and multi-article pattern recognition areincorporated into the terminal. TheBook Check Unit 500is totally enclosed by the PSCServer Terminal chassis800 case and the desensitizing area 850 of theBook CheckUnit 500 is overlaid by a similar shape on the PSCServerTerminal chassis 800.

The barcode Optical Scanner 802 is shown on theleft hand side but could also operate from the right handside. It is dependent on the positioning of the ArticleI.D.Tag 220, which could be on either the front, rear orinside cover.

The sensitizedArticle Responder 803 is integratedinto a formednon-ferrous shield structure 823 whichoverlays the case of thePSC Server 800. This samenon-ferrous shield structure also containsdetectors 805and 804, for left and right hand operation respectively,which provide signals onLine 245 for the User ActivatedDevice 263. This same formednon-ferrous structure 823also contains the BookPresent Detectors 808 and 807which connect to Line 245 for left and right handedoperation respectively.

The Article Removal Authorization Device is 806.

The terminal 800 shown in Fig. 7 is suitable for usein a library. The embodiment of Fig. 7 includes thepreferred configuration discussed above, in which certaininterrogation, sensing, and deactivation functions of theEAS system are additionally incorporated into theterminal. In this embodiment, thearticle 110 is a book,map, or other member of the collection of the library; auser of the facility is typically referred to as a"patron" of the library; and theEAS System 300 typicallyincludes as the Removal Preventer 350 a gate which isnormally locked. Typically, the patron, carrying thebook, passes through an interrogation zone immediatelybefore exiting from the library or an individualdepartment of the library; if the electronic articlesurveillance system interrogates and senses an activated marker attached to the book (i.e. the marker was nottemporarily deactivated as part of the book check outprocedure), the gate is held shut, thereby preventingegress, and perhaps also activating a visible or audiblealarm.

In the embodiment of Fig. 7, theTerminal 800detects the request of a user by the action of that userplacing his/her User I.D. 210 into a profile in thevicinity of theDetectors 805 or 804 for left or righthanded operation. Theidentification card 210 in thisembodiment has a user identification data encoded on itin the form of a bar code or by other means which can beoptically detected.Bar Code Reader 802 scans the areain the vicinity ofDetector 805 and transmits thedetected data onLine 243.

Visual instructions are displayed on theVisualDisplay Unit 801 as to the courses of action now open tothe user. Articles for authorized removal are placedinto desensitizing area 850, being placed on top of theUsers I.D. 210. The presence of an article in thisposition is sensed byBook Present Detectors 808 or 807,for left or right handed operation.Bar Code Reader 802scans the article I.D. 220 and transmits this data to thePSC Server Terminal 400.

The sensitizedArticle Responder 803 determines thepresence of asensitized Marker 310 in any of severaldetection zones and transmits this pattern to thePatternGenerator 253 in thePSC Server Terminal 400.

If authorization to issue is determined, the ArticleRemoval Authorization Device 806, an infrared LED, turnsoff, causing theBook Check Unit 500 to perform adesensitizing operation, desensitizing the sensitizedMarker 310, thereby allowing theArticle 110 to be movedthrough theEAS System 300 without activating theRemovalPreventer 350.

Fig. 8 is a side cut-away view of a preferredembodiment of theMulti-Strip Responder Assembly 803 which incorporates an array ofSensors 820 #1-8 whichcover six horizontal zones and two vertical zones.

Any number ofsensors 820 can be provided in anyconfiguration dependent on the type and style of theArticle 110 having amarker strip 310. Figs. 12A to 12Cshow various arrangements of arrays that can be useddepending on particular circumstances. Figs. 12A and 12Bshow respectively square and circular arrays that may beuseful in a stores environments in which a conveyorpasses through the centre of the array. Fig. 12C showsa semi-elliptical array.

Referring again to Fig. 8, awaveguide 821, arrangedadjacent thesensors 820 is provided to focus areas ofsensitivity of thesensors 820 intodetection zones 822which are substantially conical in shape. Thewaveguide821 acts in a manner similar to the dish of a radarantenna to focus electromagnetic energy onto thesensors820 for detection. Thedetection zones 822 may bebroadened or narrowed by the placement of thewaveguide821 fore or aft of thesensors 820. Thedetection zones822 associated with eachsensor 820 can therefore have abeam width of between about 20° to 70° and preferablyapproximately 45°. Thedetection zone 822 coverage isset according to the characteristics of the items to bedetected.

In Figs. 11A and 11B, thewaveguide 821 is shownformed of ametal block 832 in which a number ofholes832 are formed, by drilling for example. Thesensors820, in the preferred embodiment are formed as anair-cored coil of wire, as seen in Fig. 11B, which arelocateable near or within theholes 832. Theholes 832act as a simple and inexpensive tunnel which focusreceived energy into a narrow beam.

Returning to Fig. 8, themarker 310 is energized byan alternatingelectromagnetic field 830 generallyderived from an A.C. mains supply. Thefield 830 can beprovided in any known manner but in the preferred embodiment is provided as the deactivator 540 of theBookCheck Unit 500 in the manner earlier described, and actsto energize asensitized marker 310 which therebyresponds by emitting (transponding) multiple frequenciesfrom a fundamental frequency of the field 830 (e.g. 50 or60 Hz) to the 200th harmonic and higher. Due to thenature of the metal typically used in themarker 310, theharmonics decrease in amplitude substantially linearly,and hence can be detected relatively easily.

Thesensors 820 act to receive radio frequencyenergy transponded from the or eachmarker 310 that isactive within itsrespective zones 822. Thesensors 820output vialines 233 to thePattern Generator 253.

The manner in which thesensors 820 discriminatemultiple markers 310 is determined by the physicalrelationship of thedetection zones 822 and the worstcase arrangement ofarticles 110.

Referring to Fig. 10A, each of thesensors 820 aregenerally displaced from it's neighbor by 5-20 mm andpreferably about 12 mm (measured from the centre of eachsensor 820) as illustrated. Where thedetection zones822 have a beam width of at least 45°, a dead zone asdepicted in Fig. 10A exists betweenadjacent sensors820. A sensitized strip lying wholly within any one ofthese dead zones will not be detected. Themarkers 310are generally larger than 4 mm in their smallestdimension with the above preferred configuration, thedead zones are no wider or deeper than 4 mm.

The size of the dead zones is adjusted by alteringthe beamwidth of thedetection zones 822 by moving thewaveguide 821 fore and aft of thesensors 820 to narrowor broaden thezones 822 respectively.

Correct adjustment is achieved when the mid-point ofamarker 310 is seen by twosensors 820. Thereafter,following displacement of themarker 310 by about 1 mm,one of thesensors 820 no longer sees themarker 820.Accordingly, an exact switch from onesensor 820 to the other is provided when themarker 310 is movedhorizontally in front of thesensor 820.

Fig. 10B illustrates the maximum density ofmarkers310 envisaged when twobooks 110 having sensitized markerstrips 310 in the spines are laid upon each other.Typically, the outer edges of the marker strips 310 are12-14 mm apart. It will be understand that thebooks 110have to be a certain minimum dimension in order thatthere is sufficient space within which to locate themarker strip 310.

Fig. 10C shows a typical dense arrangement in whichthe strips of two adjacent books 110a and 110b are seenby threesensors 820. The strip of book 110a is seen bysensors #1 and #2 and the strip of book 110b is seen bysensor #2 and just encroaching thedetection zone 822 ofsensor #3.

The presently disclosed arrangement has been testedand consistently detects at least 80% of multiple markerstrips which represents a substantial improvement overthe detectability of prior art systems.

However, there is a minimum book size that cannot beresolved, such as that represented in Fig. 10D whereperiodicals 110d and 110e such as magazines andnewspapers have theirmarker strips 310 placed "betweenthe pages" and accordingly are longitudinally alignedwith thedetection zones 822. A high probability ofdetection is maintained because the strip edge seen inFig. 10D with respect to marker 310d extends out of thedead zone betweensensors #1 and #2 and is thereforedetectable.

ThePattern Generator 253 processes the outputs ofeachsensor 820 in a like manner and outputs a digitalpattern on the 8-bit bus 405. In Fig. 8, the internalschematic of thePattern Generator 253 is shown only forsensor #8 for clarity. Eachsensor 820 connects firstlyto aband pass filter 841 which rejects the fundamentaland the lower 20 harmonics. The next 40 harmonics are passed and the remainder rejected. The pass-band can bevaried to specific requirements. The pass-band isamplified and rectified indevice 842 which feeds againadjustment circuit 843 which allows for the detectionrange of therespective cone 822 to be adjusted to extendbetween 15-40 mm out from the surface of the formednon-ferrous cover plate 823. Signals detected by thesensor 820 are then digitized in aSchmitt trigger 844which outputs onto the corresponding line of thebus 405.

Thebus 405 thereby has a pattern of digital signalswhich is indicative of none, one, or more than one sensedactive markers 310 present in thefield 830.

The pattern is transferred to thePSC Controller 200where thePSC Link 201 processes the pattern to determinewhether none, one or more than oneactive markers 310 aresensed. ThePSC Link 201 contains a look-up table oflegitimate patterns that can be output from thepatterngenerator 253. If only onesensor 820, or if twoadjacent sensors 820 detect asensitized marker 310, thenthe determination is made that only onemarker 310 ispresent. If two non-adjacent sensors or more than twosensors in any configuration detect sensitized markerstrips 310, then the determination is made that more thanone sensitized strip is present. OncePSC Link 201determines where none, one, or more than oneactivemarkers 310 present, thePersonal Computer 604 thenissues instructions earlier described either authorizingremoval or rejecting the transaction.

Table 1 below shows those valid patterns that permitauthorization for removal. Because each patterncorresponds to a particular number, a single subtractionprocess can be used to evaluate the patterns. If eitherofsensors #7 or #8 provide a signal output,authorization is inhibited as this is indicative of theTerminal 800 not being used correctly whereby thearticle110 must be placed hard against both the horizontal and vertical surfaces of thenon-ferrous shield structure823.

Sensor	#	1	#2	#3	#4	#5	#6	#7	#8
Weight	128	64	32	16	8	4	2	1
Valid Patterns	0	0	0	0	0	1	0	0
	0	0	0	0	1	1	0	0
	0	0	0	1	0	0	0	0
	0	0	0	1	1	0	0	0
	0	0	1	0	0	0	0	0
	0	0	1	1	0	0	0	0
	0	1	0	0	0	0	0	0
	0	1	1	0	0	0	0	0
	1	0	0	0	0	0	0	0
	1	1	0	0	0	0	0	0

Fig. 9 is a side cut-away view of an alternativeembodiment of an Article Removal Authorization SignalDevice 910 which is a non-intrusive attachment to the EASBook Check Unit 500.

The existingcase 900 of theBook Check Unit 500contains two apertures in which are located aBeamTransmitter 902 and aBeam Detector 901.

A beam passes from one to the other, and when thisbeam is interrupted, it is the indication to theBookCheck Unit 500 that anArticle 110 is within thedesensitizing area 850 and that theBook Check Unit 500should perform the desensitize operation.

In this preferred embodiment anAuxiliary Device 903permanently interrupts this beam from theTransmitter 902to theDetector 901 and replaces it with a secondary beammade up from aSecondary Beam Transmitter 904 and theexistingBeam Detector 901.

Secondary Beam Transmitter 904 is controlled byLine710 from the Article RemovalAuthorization signal Circuit490.Line 710 is switched to "interrupt" status when thePSC Server 400 is instructed to authorize articleremoval.

The foregoing describes only a number of embodimentsof the present invention and modifications, obvious tothose skilled in the art can be made thereto.

Claims (12)

1. A detector assembly for use in an electronic articlesurveillance system, said detector assembly providing amagnetic field (830) to energize sensitized markers (310)which transmit energy for detection by sensors (820), saiddetector assembly characterized in that it comprises:

   a plurality of sensors (820), and said magnetic field(830) is provided in several regions, each region being associated with each of said sensors,said regions forming zones of sensitivity (822) for saidsensors, in which zones an energized sensitized marker will be detected by the associated sensor;

   processing means (200, 400) connected to said sensorsfor providing a detection pattern corresponding totransmitted energy detected by one or more of said sensors(820), processing said detection pattern to attempt todetermine if none, one, or more than one of said markers(310) is present in said zones of sensitivity (822), and indicatingwhich one among these three determinable marker presence alternatives was determined.
2. A detector assembly as claimed in claim 1 wherein deadzones within said magnetic field (830) and outside saidzones of sensitivity (822) are no larger than a smallestdimension of said markers (310).
3. A detector assembly as claimed in claim 2 wherein saidsensors (820) are spaced apart at between 5 to 20 mmcentres.
4. A detector assembly as claimed in claim 3 wherein saidsensors (820) are spaced apart at about 12 mm centres.
5. A detector assembly as claimed in claim 1, whereinsaid sensors (820) are arranged such that the zones ofsensitivity (822) of adjacent sensors (820) overlap.
6. A detector assembly as claimed in any of claims 1through 5 further comprising focusing means (821)associated with said sensors (820) for determining a shapeof said zones of sensitivity (822).
7. A detector assembly as claimed in claim 6, whereinsaid zones (822) are substantially conical in shape.
8. A detector assembly as claimed in claim 6 wherein saidfocusing means (821) is adapted to vary a detection beamwidth of said zones (822).
9. A detector assembly as claimed in claim 6 wherein saidfocusing means (821) comprises a waveguide (821) formed ofat least one metallic section (831) having a plurality ofholes (832) corresponding to said sensors (820), one ofsaid sensors (820) being located near or within each one ofsaid holes (832).
10. A detector assembly as claimed in claim 1, whereinsaid processing means (200, 400) includes computing means(201) for determining whether one or more than one of saidmarkers (310) are detected within more than one of saidzones (822) by analyzing the pattern derived from adjacentones of said sensors (820).
11. A detector assembly as claimed in claim 10 whereinsaid computing means (201) includes a look-up table ofpredetermined patterns which are correlated with saidpattern so as to indicate none, one, or more than onesensitized markers within said field (830) and said zones(822).
12. An article removal control system for enabling removalof a selected one or more of a plurality of articles (110)from a facility (100), said system comprising:

    an article inventory control sub-system in which eachsaid article and each user of said facility is identifiableto record and process information regarding authorizationor inhibiting removal of one or more of said articles (110)by an individual said user, each said article (110) beingprovided with a sensitizable marker (310) that is desensitized to permit removal of an article from saidfacility (100) and sensitized on return to said facility(100);

    a desensitizer (850) connected to said articleinventory control sub-system for desensitizing a marker(310) to permit removal of the corresponding article (110)from said facility (100) upon authorization from saidarticle inventory control sub-system; and

    a detector assembly as claimed in claim 1 connected tosaid article inventory control sub-system to permitauthorization of said desensitizer when only one sensitizedmarker (310) is detected within said zones (822).

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