AU749545B2 - Active object tags - Google Patents

Description

S&F Ref: 520030

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant Canon Kabushiki Kaisha 30-2, Shimomaruko 3-chome, Ohta-ku Tokyo 146 Japan Sue-Ken Yap Actual Inventor(s): Address for Service: Invention Title: Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 Active Object Tags ASSOCIATED PROVISIONAL APPLICATION DETAILS [33] Country [31] Applic. No(s) Australia PQ2702 [32] Application Date 8 September 1999 The following statement is a full description of this invention, including the best method of performing it known to me/us:- Docmens rC0e:v0d ol: 2 9 AU6 2000

CD

ftch jo: 5815c [R:\LIBU]04338.doc:mp -1- ACTIVE OBJECT TAGS Field of the Invention The present invention relates to a method and apparatus for locating objects.

The invention has been developed primarily for tagging and locating objects and will be described hereinafter with reference to these and related applications. However, it will be appreciated, particularly in view of the large number of alternative examples given, that the invention is not limited to these fields of use.

Background Art A problem that is often faced is the need to locate misplaced objects, or .ooo.i alternatively to maintain timely and accurate information regarding the position of objects which may alter in their location. For example, car keys are often placed on the nearest table when enters a home and their location is often forgotten when the keys are next required for use.

A variety of tag identification arrangements have been developed to address the simple issue of identifying articles. Such are commonly used in personnel tags for perimeter security and access systems and also in article identification, for example books within a library. Identification tags are either active or passive and emit a binary code which uniquely identifies the tag and therefore allows the identification system to decide whether the person or article carrying the tag is allowed to perform some function, such as the person entering a building or the book leaving the library. Active tags possess their own power supply, electromagnetic sensor and circuitry that permit responding to electromagnetic emissions in a selected band of the radio frequency spectrum. Passive tags rely upon the emitted electromagnetic radiation of an interrogating device forming part of the identification system to provide for emission of the unique binary code.

Examples of passive tags include surface acoustic wave (SAW) devices which contain no 520030.doc:iad -2active circuitry, and also devices that utilize the emitted electromagnetic radiation to provide energy sufficient to operate active circuitry within the tag. Passive tags currently available require substantial proximity between the tag and the interrogating device, typically less than a few metres.

U.S. Patent No. 5,689,238 (Cannon, Jr., et al.) discloses methods and systems for locating objects based on electronic tags that respond to a unique code when interrogated.

The tag emits a sound or produces an external response when the transmitted code matches the code stored in the tag. A system for displaying the location of the tag is also disclosed.

ooooo U.S. Patent No. 5,798,693 (Engellener) discloses methods and apparatus for identifying the location of objects, again using a unique code stored within the tag. A S system for searching one or more spatial regions for tagged items is also disclosed as well as mechanisms for identifying objects within the interrogated region.

Existing identification schemes rely on maintaining an up-to-date database of mappings between articles that relate to a groups or classes of articles. Such a database is S required to relate a list of the individual articles to lists in which the various groups or classes are identified. The maintenance of such a database can become a significant burden, particularly where are large number of articles are present or in use.

It is an object of the present invention to provide an alternate identification system which affords greater functionality than existing arrangements.

Summary of the Invention The present invention addresses the above-noted object through providing an altered identification of individual tags, the altered identification including language components which enable individual sets or classes of tags to be uniquely characterised as well as individual tags within the system. Such an arrangement therefore allows for the 520030.doc:iad -3identification of individual locations of articles and/or locations of articles meeting a particular class or group. The arrangement also facilitates the searching of multiple locations simultaneously.

In accordance with one aspect of the present disclosure there is provided a system for locating objects, each said object having a tag identifier device and being interrogable by an interrogation expression formed from a regular expression query language.

In accordance with another aspect of the present disclosure, there is provided a location system for objects, each said object being associated with a tag transponder identifier device, characterised in that a unique identification code incorporated with each said identifier device comprises a string of alphanumeric characters forming at least one interrogation component, each said interrogation component forming a part of a description of said object.

In accordance with another aspect of the present disclosure, there is provided a system for locating objects, each of said objects being associated with a corresponding identification tag, said system comprising: :i a plurality of transceiver devices each having an associated address code and being arranged at distributed locations about said system, each said transceiver device being configured to emit a corresponding interrogation signal within the corresponding location and to receive response signals from zero, one or more of said tags at said corresponding location; control means for selectively generating at least one of said interrogation signals and for interpreting corresponding one or more said response signals from said tags; characterised in that a unique identification code associated with each said tag r comprises a (first) string of alphanumeric characters, said first string comprising at least 520030.doc:iad -4one word associated with an identifiable set of said objects, and said one interrogation signal comprises a (second) string of alphanumeric characters comprising at least one of: a component associated with said one word of at least one said object; and (ii) a hierarchical name space associated with at least one said address code.

In accordance with another aspect of the present disclosure, there is provided a method of identifying at least one of a plurality of objects, each said object incorporating an identification tag having a unique code, said method comprising the steps of: establishing each of said codes using an alphanumeric string of characters, each said code including at least one word related at a predetermined set of said objects; °.forming a search expression incorporating a functional relationship including at S least one of said characters, said functional relationship permitting discrimination between said sets; interrogating each of said tags using said search expression whereby each said tag evaluates a match with said search expression; monitoring responses from those said tags that match said search expression.

Other aspects are also disclosed.

Brief Description of the Drawings A number of embodiments of the present invention will be described with reference to the drawings in which: Fig. 1 is a schematic illustration of an identification system; Fig. 2 is a schematic block diagram representation of a computer apparatus useful in the system of Fig. 1; Fig. 3 is a schematic block diagram representation of a preferred tag structure; and 520030.doc:iad Fig. 4 is a flow chart depicting the recognition process performed in the system of Fig. 1.

Detailed Description Fig. 1 shows an identification system 100 which provides for locating a number of tags 150, 152 and 154 which may be physically distributed about the system 100. The tags 150-154 may be provided with any appropriate technology and may be formed from passive or active arrangements. Preferably, active tags are used to permit greater interrogation and response distances, and such tags incorporate electronic circuitry operated via an internal power supply. Advantageously the power supply includes a 10 battery and a solar cell for recharging the battery. The tags 150-154 are configured to respond to emissions preferably formed within the radio frequency spectrum.

Alternatively the emissions may be formed in the infra-red spectrum or ultrasonically, for example. Modulated returns by tags preferably correspond in nature to the interrogating emissions.

In contrast to prior art arrangements, where tags are identified by unique binary numbers, the tags 150, 152 and 154 comprise sequences of characters in an alphanumeric character set thus forming, for each tag, a unique identifier string. Interrogating emissions and modulated returns are configured in such a fashion so as to carry the characters in order to uniquely identify each tag 150-154.

As seen in Fig. 1, the system 100 incorporates a controlling computer system 102 formed in a traditional fashion utilising a computer module 104, video display 106 and controlling input devices such as a keyboard 108 and a mouse pointing device 110.

Connected to the computer module 104 is a tag programming device 120 into which a tag, such as the tag 150, may be inserted for the purposes of programming the corresponding unique code therein. In this fashion, the particular code desired by the user may be 520030.doc:iad -6entered via the computer system 102 and directly programmed via the programmer 120 into the tag 150.

Also connected to the computer system 102 is a transceiver apparatus 122 which is coupled to a number of transponders 132 and 134 via respective connections 124 and 126. The transponders 132 and 134 are distributed throughout one or more areas in which the system 100 is to be operative. For example, when the system 100 is configured for operation within a domestic home, the transponders 132 and 134 may be located in different rooms of the home. Alternatively, transponders may be arranged within a factory or warehouse environment in such a fashion that their radiating fields of influence 10 cover areas in which tagged articles are to be located. As seen in Fig. 1, the transponders 132 and 134 are arranged in respective rooms 128 and 130 in each of which there are articles. The room 128 includes two books 136 and 138 and the room 130 including a hand gun 140. Each of the articles 136, 138 and 140 has attached to it a respective uniquely programmed tag 152, 154 and 156. The transceiver 122, under control of the computer system 102, is configured to provide for an interrogation emission selective of any one or more of the rooms 128 and 130. When an emission is detected by any tag, one of a number of alternatives may be configured to occur.

S. In a first system, the transmission may be simplified, for example through the emission of a single burst of continuous wavelength, which causes each of the tags within the field of influence of the burst to respond with a corresponding unique identification code. In an alternative system, the transmission may be intelligent and incorporate specific interrogation information that is interpretable by the tags within the respective field of influence so that only those tags fitting a particular type of interrogation provide a response. The transponders 132 and 134 receive replies from tags and convey the replies 520030.doc:iad to the transceiver device 122. Received signals are then communicated to the computer system 102 for examination and identification.

In a specific implementation, each of the books 136 and 138 may be identified in a unique fashion by an appropriate descriptive identifier. Such a descriptive identifier may for example include the nature of the article, its source and a number for indexing purposes. In the system 100, a user may wish to identify books by the name of the author and the date in which they were purchased by the user. Accordingly, the book 136 may be identified by the following identifying sequence of characters: bookMilesFranklinl19990609 and the book 138 might be identified as bookTimWinton 19990609.

S•In this fashion, each of the books may be appropriately programmed by the nature of its character, the author and its date of purchase.

•go.

Similarly, the gun 140 may be programmed according to its nature as a sports implement, its particular type, and a cataloguing number, such as: sportgun007.

.l In a preferred use of the system 100, the transmissions output from the transponders 132 and 134 comprise a sequence of alphanumeric characters which form a key that provide for direct matching with components of the programmed tagged identifiers. In addition to normal alphanumeric characters, certain other characters (eg.

meta characters) that are defined to have special meanings may also be transmitted. The particular technique used relies upon the use of "regular expressions" embodied, amongst other places, in the command language of the Unix Operating System (trade mark) and other operating systems, for example MS DOS (trade mark). A specific implementation 520030.doc:iad -8of the above-described arrangement follows the Unix "Born Again Shell" (BASH) definitions for meta characters. Such definitions include: The character stands for any sequence of characters at that point. For example, the interrogating expression "key*" will match "keys" and "key chain". In another example, "*key" will match car-key and house-key.

Square brackets enclose a list of characters that are to match at that point. Within the list, the hyphen, if not at the beginning or the end of the list, that is say surrounded by two characters, matches that ranges of characters. For example, the expression [abl-n]* will match any name starting with any one of the characters a, b, I, n or m.

9 Open and closed parenthesis (braces) enclose a list of comma-separated alternatives. For example, [key*,book*] will match any name starting with key or *o S book.

As a final example, a person searching for any books purchased in the current month, assuming the current month is June 1999 and that the books have been tagged 15 appropriately with the purchase date, such books could be found using the expression: book*199906* There are many additional enhancements to this basic notation, including turning on or off lower/upper case sensitivity, the use of specifiers on the length of matching expressions, and so forth. Those skilled in the art will readily comprehend that such enhancements do not depart from the spirit and scope of the invention.

The regular expression that is broadcast to the transponder devices 132, 134 can be matched against the identifier string in the tag device 150 156 using, for example, one of a number of methods known to computer scientists and programmers.

A first method performs the matching using a "deterministic finite automata".

The regular expression is converted to an equivalent non-deterministic finite automata 520030.doc:iad -9- (NDFA) using a process described in "Introduction to Automata Theory", by John E.

Hopcroft and Jeffery D. Ullman, Addison-Wesley, 1979 (hereinafter Hopcroft et. al.).

The NDFA may then be converted into the equivalent deterministic finite automata (DFA) using another process described by Hopcroft et. al. The DFA can be implemented in software as a state machine. Methods for constructing state machines in software are well known per se by computer scientists and programmers.

A second method performs matching between the regular expressions and the identifier strings using a "backtracking algorithm", also known to computer scientists and programmers. For example, the library of the Berkeley Standard Distribution (BSD) Unix, other distributions of Unix, as well as in free software repositories, contain backtracking routines in such form as, or equivalent to, recomp and re_exec, which *.4*O compile a regular expression to an internal form, and test for a match between the internal form of the regular expression and the identifier string, respectively.

Other methods for matching the regular expression to the identifier string may *b also be used.

In a preferred implementation, when a tag has detected a match between its own unique code and the transmitted expression, the tag may indicate its presence by beeping S"or otherwise generating a detectable output, for example sending a radio signal.

Returning to the arrangement of Fig. 1, in addition to their electronic code, the tags 152-156 may also include a human readable version of the name or alternatively a bar code version. The tags 152-156 may be affixed to the object using any appropriate fastening arrangement.

As seen in Fig. 1, a user interface formed by the computer system 102 can include icons 112 and 114 displayed on the display screen 106. The icons may be selected using a mouser pointer 116 to select particular classes of items. For example, if 520030.doc:iad the books icon 112 is selected, the transceiver 122 may be configured to emit the expression "book*". Each of the books 136 and 138 may then respond via their respective tags 152 and 154. The system 106 may then display the location of those books 136 and 138 as residing within the room 128, as indicated by the transponders 132 from which appropriate responses are detected. Similarly, an enquiry using the sports icon 114 will return indication of the presence of the gun 140 within the room 130.

In a further configuration, once a particular article is identified, a transmission from the transceiver 122 may be configured to cause the particular tag to provide a human detectable emission such as a beep or flashing light, thereby permitting the particular tagged item to be readily located within the room.

The identification system described above can be extended to multiple locations through the use of path names, in a manner akin to the syntax of file names within the Unix Operating System or MS DOS, or World Wide Web URL's. For example, path names may be used to identify all tagged articles of a particular type within a particular location using an appropriate syntax. For example, the expression {kitchen, bedroom}/*key :i when transmitted would enquire of any object including the term "key" located in either the kitchen or the bedroom. Functionality is facilitated through each of the transponders 132 and 134 being individually connected to the transceiver 122 thereby permitting transmissions and receptions to be multiplexed.

Extensions of the present arrangement are possible into multiple hierarchical arrangements to provide for precise location of particular classes of items that are appropriately tagged.

The system 100 of Fig. 1 may be practiced using conventional tags of a variety of technologies, and complementary transponders driven via a conventional transceiver, 520030.doc:iad -11the tags being programmed by an appropriate conventional programming device. The system 100 is characterised by the nature of the unique codes with which the tags are programmed and the free-formed interrogation techniques of those codes, or components thereof.

s A preferred interrogation process 400 is shown in Fig. 4 and commences with a step 402 at which the object tag is initialised. This may occur immediately upon programming in or removal from the programmer 120. At step 404 the object tag awaits receipt of a broadcast. On receipt of a broadcast, at step 406 the object tag decodes therefrom the regular expression (RE) contained therein which, at step 408, is compiled to 1o form a specification for a backtracking algorithm. At step 410 a match is assessed between the identifier of the object tag and the regular expression by applying the backtracking algorithm. At step 412 a check is made if the identifier matches the regular expression. If not, the process 400 returns to step 404 (ie. no action is taken). If there is a match, step 416 follows and the object tag emits a return signal, typically including its unique identifier. The inclusion of the identifier in the return signal is not essential. For example, if a broadcast is made to identify a single tag, then only that tag will respond and the corresponding transponder will provide the location.

The computer system 102 may be formed by a general-purpose computer system 200, such as that shown in Fig. 2 wherein the tag programming and interrogation techniques may be implemented as software, such as an application program executing within the computer system 200. The software may be divided into three separate parts; one part for tag programming, another for carrying out the interrogation techniques; and another to manage the user interface between the above noted parts and the user. The programming part may incorporate a menu-driven cataloguing system that provides for 25 the systematic and hierarchical coding of the unique alphanumeric code onto each tag, 520030.doc:iad -12thereby facilitating standardisation of searching expressions through hierarchical optimisation. Different menus may be used for according to the type of system being implemented (eg. home, library, warehouse, factory, personnel access etc). The software may be stored in a computer readable medium, including the storage devices described below, for example. The software is loaded into the computer from the computer readable medium, and then executed by the computer. A computer readable medium having such software or computer program recorded on it is a computer program product.

The use of the computer program product in the computer preferably effects an advantageous apparatus for location identification.

10 The computer system 200 comprises a computer module 201, input devices such as a keyboard 202 and mouse 203, output devices including a printer 215 and a display device 214. A Modulator-Demodulator (Modem) transceiver device 216 is used by the .oo• computer module 201 for communicating to and from a communications network 220, for •o example connectable via a telephone line221 or other functional medium. The modem 216 can be used to obtain access to the Internet, and other network systems, such as a Local Area Network (LAN) or a Wide Area Network (WAN). For example one or more of the transceivers 122 may be coupled to the network 220 thereby permitting the •o e system 100 to be distributed over a vast area, possibly incorporating many buildings at disparate locations.

The computer module 201 typically includes at least one processor unit 205, a memory unit 206, for example formed from semiconductor random access memory (RAM) and read only memory (ROM), input/output interfaces including a video interface 207, and an I/O interface 213 for the"leyboard 202 and mouse 203 and optionally a joystick (not illustrated), and an interface 208 for the modem 216. A storage device 209 is provided and typically includes a hard disk drive 210 and a floppy disk 520030.doc:iad 13drive 211. A magnetic tape drive (not illustrated) may also be used. A CD-ROM drive 212 is typically provided as a non-volatile source of data. The components 205 to 213 of the computer module 201, typically communicate via an interconnected bus 204 and in a manner which results in a conventional mode of operation of the computer system 200 known to those in the relevant art. Examples of computers on which the embodiments can be practised include IBM-PC's and compatibles, Sun Sparcstations or alike computer systems evolved therefrom.

Typically, the application program is resident on the hard disk drive 210 and read and controlled in its execution by the processor 205. Intermediate storage of the 10 program and any data fetched from the network 220 may be accomplished using the semiconductor memory 206, possibly in concert with the hard disk drive 210. In some instances, the application program may be supplied to the user encoded on a CD-ROM or floppy disk and read via the corresponding drive 212 or 211, or alternatively may be read by the user from the network 220 via the modem device 216. Still further, the software can also be loaded into the computer system 200 from other computer readable medium including magnetic tape, a ROM or integrated circuit, a magneto-optical disk, a radio or infra-red transmission channel between the computer module 201 and another device, a computer readable card such as a PCMCIA card, and the Internet and Intranets including email transmissions and information recorded on websites and the like. The foregoing is merely exemplary of relevant computer readable media. Other computer readable media may be practiced.

A specific example of a tag structure useful for the tags 150-156 is shown in Fig. 3 where a tag 300 includes a battery 301 that is enabled for replenishment via a solar cell 302. A power control unit 309 couples the battery 301 to a power bus 311 which supplies other components within the tag 300, this not being illustrated for the sake of 520030.doc:iad -14clarity. The power control unit 309 is configured to detect the reception of an interrogation signal via a Rx/Tx transponder 303, at which time the bus 311 may be enable for a predetermined period of time sufficient to process the interrogation and forward any reply. The transponder 303 also couples any received signal to a communications controller 304 for demodulation and differentiation between programming instructions and interrogation instructions. Programming instructions are passed via a line 305 to a program function unit 306 configured to update a non-volatile memory 308 in which the programmed unique code is stored. Depending on the nature of the memory 308, a permanent connection to the battery 301 may be required, as will be appreciated by those skilled in the art. Interrogation instructions are passed via a S connection 316 to an interpreter 314 which controls a matching operation performed by a matching unit 313 which compares the unique code from the memory 308, or parts thereof, with one or more components of the interrogation instruction. As a consequence of a match or no-match, the matching unit 313 and the interpreter 314 control a response formatter 312 which generates a response signal 315 that may be encoded by the communications controller 304 for transmission via the transponder 303 to the interrogating device (eg. the transponder 132).

With such an arrangement, the tag 300 may retain an alphanumeric code and perform matching on any components thereof according to an interrogation instruction, which may include a plurality of interrogation commands.

Industrial Applicability It is apparent from the above that the arrangements described above are applicable to the interrogation and identification industries and for the locating of articles.

Such arrangements offer a significant increase in ease of system management and article location than prior art arrangements. For instance, with prior art arrangements, where 520030.doc:iad each tag code is formed by a single number (often a 32 or 64-bit code), functionality corresponding to that of the above-described arrangement may only be obtained by including within a controlling computer system one or more mapping tables that maps article types, locations, catalogue numbers and the like to the specific code number of each tag. Such requires substantial management resources to establish the tables and update their status as the system changes. The arrangements disclosed with respect to Figs. 1 to 4 and described above, obviate a need to establish such tables, lists and mapping because individual articles or classes of articles may be identified through interrogation using a meaningful string.

10 The foregoing describes only some embodiments of the present invention, and o°•o Smodifications and/or changes can be made thereto without departing from the scope and spirit of the invention, the embodiments being illustrative and not restrictive.

In the context of this specification, the word "comprising" means "including principally but not necessarily solely" or "having" or "including" and not "consisting only of'. Variations of the word comprising, such as "comprise" and "comprises" have corresponding meanings.

a. o. a 520030.doc:iad

Claims (4)

1. A location system for objects, each said object being associated with a tag transponder identifier device, characterised in that a unique identification code incorporated with each said identifier device comprises a string of alphanumeric characters forming at least one interrogation component, each said interrogation component forming a part of a description of said object.

2. A system according to claim 1, wherein said interrogation component comprises a regular expression being a part of a predetermined set of regular expressions defining a query language. .oo.oi

3. A system according to claim 1 or 2, wherein said interrogation component comprises at least one predetermined character string, said one character string being associated with an identifiable set of said objects, said system further comprising of a is matching means configured to determine a match between said character string and a query used to interrogate said identifier device. O*O. :i

4. A system according to claim 3 wherein said one string comprises a word of a O•Q•• spoken language. A system according to claim 3, wherein said query comprises of said regular expression and said matching means is configured to determine membership of said object within said query by comparison of said unique identification code with said regular expression.

520030.doc:iad 17- 6. A system according to claim 3 or 5, wherein said matching means is configured within said identifier device. 7. A system for locating objects, each of said objects being associated with a corresponding identification tag, said system comprising: a plurality of transceiver devices each having an associated address code and being arranged at distributed locations about said system, each said transceiver device being configured to emit a corresponding interrogation signal within the corresponding location and to receive response signals from zero, one or more of said tags at said corresponding location; control means for selectively generating at least one of said interrogation signals ooo o and for interpreting corresponding one or more said response signals from said tags; characterised in that a unique identification code associated with each said tag comprises a (first) string of alphanumeric characters, said first string comprising at least one word associated with an identifiable set of said objects, and said one interrogation a. "•signal comprises a (second) string of alphanumeric characters comprising at least one of: a component associated with said one word of at least one said object; and (ii) a hierarchical name space associated with at least one said address code. 8. A system according to claim 7, wherein said component comprises at least one character associated with a logical operation related to said one word and at least one character of said one word. 520030.doc:iad -18- 9. A system according to claim 7 or 8, wherein said hierarchical names space comprises at least one character associated with at least one said address code to enable identification of those of said objects at the corresponding said location. 10. A method of identifying at least one of a plurality of objects, each said object incorporating an identification tag having a unique code, said method comprising the steps of: establishing each of said codes using an alphanumeric string of characters, each said code including at least one word related at a predetermined set of said objects; forming a search expression incorporating a functional relationship including at least one of said characters, said functional relationship permitting discrimination between said sets; oooo interrogating each of said tags using said search expression whereby each said 0tag evaluates a match with said search expression; monitoring responses from those said tags that match said search expression. *o 11. A system for locating objects, each said object having a tag identifier device and being interrogable by an interrogation expression formed from a regular expression query •language. 12. A system according to claim 11, wherein each said tag identifier device comprises a unique identification string and matching means for comparing said string with said interrogation expression to permit emission of an acknowledgment response on the occurrence of a match between said string and said expression. 520030.doc:iad -19- 13. A system according to claim 12, wherein said matching means performs a matching function determined by said interrogation expression upon at least one component of said unique identification string. 14. A system according to claim 13, wherein said matching function utilises one of a backtracking algorithm or deterministic finite automata. An identification system substantially as described herein with reference to Fig. 1, or Figs. 1 and 2 or Figs. 1 to 3, of the drawings. e e S* o9 o oo* 520030.doc:iad 16. A method of interrogating one or more tags within an identification system substantially as described herein. DATED this ninth Day of April, 2002 CANON KABUSHIKI KAISHA Patent Attorneys for the Applicant t0 SPRUSON&FERGUSON 520030.doc:iad