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RFID Locating Systems for Linking Valued Objects with Multimedia Files

by Jeff Lindsay, Walter Reade, Maryellen Vicksta, and Bernie Kressner

The following article was published Dec. 23, 2003 on IP.com as Article 21113D, available at https://priorart.ip.com/viewPub.jsp?pubID=IPCOM000021113D.

Related articles at JeffLindsay.com on radiofrequency identification (RFID) technology:


Table of Contents


RFID Locating Systems for Linking Valued Objects with Multimedia Files

Jeff Lindsay, Walter Reade, Maryellen Vicksta, and Bernie Kressner
Nov. 25, 2003

Introduction

Many new applications have been proposed for smart tags employing radio frequency identification (RFID) technology. While it is well known to use RFID to track the location of products as they move through portions of the supply chain and in other industrial applications such as baggage handling at airports, less attention has been given to the potential of RFID to assist in the storage and archiving of items and associated information about the items outside of industrial operations. In this paper, we propose a number of RFID-based applications for improved handling of valuable items such as heirlooms and other sentimental items in home use, as well as improved methods for commercial processing of valuable goods and information associated with these goods. Based on recent advances in RFID and multimedia data handling, we propose a variety of hardware and software systems and associated methods to help individuals and groups better deal with valuable items that need to be stored or archived. Though the focus of this paper is on systems for home or other non-commercial use, any of these systems can also be applied to any commercial setting or can be combined with other information-handling and object-tracking technologies (e.g., barcode systems, 2-D barcodes, or the nanobarcode systems of Nanoplex Technologies, Inc. of Mountain View, California, described at www.nanoplextech.com).

Adapting Technology from Optical Systems

Many concepts developed for image-based information systems can be adapted to RFID systems. For example, past systems have used photographs to create catalogs of inventory, to document the location of objects, or to identify objects. For object identification, image recognition and classification tools, including biometrics, have been used. All of these systems can be enhanced or replaced with RFID-based systems.

Enhancement of an image-based system can occur by combining image-based systems with RFID, relying on RFID to positively identify an object (e.g., a tag with a known serial number is attached to the object, and a scanner can then identify the object from a distance, even when it cannot be viewed). A database of images of various objects can be coupled with their RFID codes, and the location of the object can be determined visually, by RFID scanning, by manual entry of position information, and so forth. The location information can then be linked to the image database and the RFID code. In such a system, a user seeking an object can preview the object in a database, and then perform an RFID scan to find the object, or can locate an object manually and scan its RFID code to retrieve previously obtained image information, including multimedia data such as video recordings of the object in use. Many other combinations of actions can be performed.

An image-recognition system for object tracking can be replaced entirely by RFID systems, including a computer system associated with a database of electronic product codes and a number of RFID scanners. The scanners can scan a selected object to read its code, which can then be used as a pointer to retrieve information from a database associated with RFID codes or to write new information to a database. The information can include data about the manufacturing process, the movement of the object during its lifetime (e.g., list of locations, dates, and owners), product specifications, directions for use, multimedia information such as a video showing how the object was manufactured or showing clips of the objects use by a former owner, etc. Nostalgic information in any form can also be associated with the object.

One example of known cameras and video systems for tracking the location of objects is described by Fatih Porikli and Ajay Divakaran in "Multi-Camera Calibration, Object Tracking and Query Generation," Mitsubishi Electric Research Laboratory report no. TR-2003-100, August 2003, available online at http://www.merl.com/papers/docs/TR2003-100.pdf. According to the abstract:

An automatic object tracking and video summarization method for multi-camera systems with a large number of non-overlapping field-of-view cameras is explained. In this framework, video sequences are stored for each object as opposed to storing a sequence for each camera. Object-based representation enables annotation of video segments, and extraction of content semantics for further analysis. We also present a novel solution to the inter-camera color calibration problem. The transitive model function enables effective compensation for lighting changes and radiometric distortions for large-scale systems. After initial calibration, objects are tracked at each camera by background subtraction and mean-shift analysis. The correspondence of objects between different cameras is established by using a Bayesian Belief Network. This framework empowers the user to get a concise response to queries such as which locations did an object visit on Monday and what did it do there?

Coupling the visual information from such systems with RFID information from tags on the objects or persons being tracked will enrich the information available and improve tracking.

Background: RFID Technology and Locating Systems

RFID is the use of radio frequency signals to read information on a small tag. RFID tags can be passive tags that rely on RF energy from an RFID scanner to activate a circuit and provide power to a small antenna that retransmits a weak signal, or they can be active tags that have their own power source for generating an RF signal containing information to be read by a scanner. Most RFID tags in use contain microchips to provide identity information or other information, but chipless tags and taggants such as nanobarcodes are also available (see, for example, J. Electroanal. Chem., Vol. 95, 2002, p. 522).

RFID tags have been around for decades, but only in recent years have technological advances created the prospect of tags so inexpensive that they could be used ubiquitously for individual products in retail markets. The low-cost tags, passive proposed for ubiquitous use and advocated by MIT's Auto-ID Center contain 96 bits of information capable of delivering a unique electronic product code (EPC) for each product. Information about the product--its manufacturing history, purchase history, etc.--could be tracked in databases, using the electronic product code as a unique identifier or pointer.

RFID has been used in many ways to locate objects. The most common approach is to tag the objects with RFID chips, and then to have a variety of RFID readers at known locations scan for nearby chips. When a chip is scanned, it is known that the chip is in the location of the scanner. For example, basic supply chain systems can use a variety of RFID readers to scan objects as they move through a factory, allowing the location of objects to be determined as they pass near RFID scanner. In such cases, proximity to a single scanner detects the presence of the item. Such systems tend to only resolve the location of the object to somewhere within the read range of the scanner.

A more precise system employs RFID triangulation. When an object is scanned by multiple scanners with measurable delay times in signal response to an emitted radio wave, then comparison of the delay times for multiple scanners can be used to triangulate the position of the object being scanned. Another approach is to have movable scanners that identify the presence of RFID chips in their vicinity, wherein the location of the scanner at any time can be identified. For example, humans or robots may move through a storage facility scanning continuously to perform an inventory and to determine the location of objects. A more expensive approach is to tag objects with active RFID tags associated with a miniature GPS-type device, such that the article can read its location and transmit an RF signal giving its GPS-determined location.

The news article "RTLS Links Active and Passive RFID" from the RFID Journal, Feb. 14, 2003 (available online at http://www.rfidjournal.com/article/view/304) describes advances in real time locating systems (RTLS) based on RFID technology, in which RFID tags coupled with RF scanners can be used to track the location of objects in real time (e.g., locations updated every few seconds). An example of an RTLS provider is RF Technologies of Brookfield, Wisconsin, whose PinPoint Mobile Resource Manager software product allows companies to track items with either passive or active RFID tags. For tracking objects in large areas where remote scanning may be needed, active (battery-powered) RFID tags are used. The company's T50 tag can communicate with a reader up to 200 feet away indoors or over 300 feet away outdoors. The reader's antenna passes data to computers that determine the position of a tagged item to within 10 feet. The product also allows users to track assets with passive tags and suitable readers. Hardware and software for RTLS are also provided by many other companies, such as WhereNet, Inc. (Santa Clara, California). WhereNet's tags, such as the WhereTag® III, can be used in an RLTS as described at http://www.wherenet.com/pdfs/WhereTag%20III%209.3.03.pdf.

Rather than tagging a movable object with RFID tags and then using one or more readers of known location to determine the location of the object, the object may carry a reader that interacts with RFID tags at known locations. For example, a Procter & Gamble warehouse in Spain has RFID scanners mounted on movable forklift vehicles, and RFID chips embedded in the concrete floor at numerous locations, with the code of each chip associated in a database with its position in the warehouse (see http://www.rfidjournal.com/article/articleprint/291/-1/4/, http://www.eu.pg.com/news/spainradiofrequency.html, and http://www.ems-rfid.com/apps/procter_gamble.html). As the forklifts move in the warehouse, they scan for the nearest RFID chip, and the code of scanned chip can then be used to identify the location of the vehicle. In related embodiment, we also propose that the location of emergency response personnel in a building (in which GPS location system do not function well) could be tracked automatically in a building with numerous RFID tags dispersed at known locations throughout the building, if the emergency response personnel have RFID scanners mounted on them for continuous monitoring of nearby RFID tags. Scanning the electronic product code from the RFID chip can then be used to look up the location of the scanned RFID tag from a database.

US Pat. No. 6,600,418, issued July 29, 2003 to R.C. Francis et al. of 3M Innovative Properties Company, discusses an object tracking and management system based on RFID in which objects having RFID tags are moved about in an environment such as a warehouse that is also labeled with many RFID tags at known locations that serve as reference tags. A moving transport vehicle equipped with an RFID reader can read the tags on objects being moved, as well as the reference tags installed in known locations, and thereby identify the location of the objects as they are moved. The reader on the transport vehicle can communicate with a dispatch station or other operators. Based on the RFID location system, the operator of the transport vehicle be given directions about the location of an object to be retrieved, where to take the objects, and can be informed of any errors made in carrying out instructions. New locations of objects when they are moved by the transport vehicle can be automatically determined and updated in a database.

The system discussed in the Francis patent, US Pat. No. 6,600,418, can be adapted for other purposes as well. A home, school, or office environment, for example, can be retrofitted or initially constructed to have RFID tags fixed in multiple known locations to serve as reference tags, with the locations being recorded in a database. The tags may be embedded in flooring, placed under carpet or tiles, mounted in walls (e.g., within drywall, wood, or, plaster), installed in wooden beams, placed in ceiling tiles, attached to light fixtures, and the like. The reference tags can be installed close enough to one another that an RFID reader in any location of interest can read at least one nearby reference tag to determine the approximate location of the reader. Triangulation can be used when multiple tags are sensed to more precisely determine location. Variable signal strength in the reader can be used to determine which of two or more detected reference tags is closest to the reader (signal strength is lowered until one of the reference tags drops out of the read signal, suggesting that the dropped out tag is most remote--though this may be incorrect when factors other than distance attenuate the strength of the signal received). Then, rather than using a transport vehicle equipped with an RFID reader, an operator may use a handheld RFID reader, such as a PDA device or cell phone that is equipped with a small RFID reader, such as the readers of AWID (see Jeffrey Jacobsen, "Low Cost, Digitally Amplified Shelf Antennas," Proceedings of the Smart Label Europe 2003 Conference (available on CD-ROM), Cambridge, England, Sept. 29-30, 2003, sponsored by IDTechEx) or the RFID reader on a compact flash card marketed by Syscan International for reading 13.56 MHz ISO-compliant tags or for other frequencies, as described in the news item, "Get RFID Readers in a Flash (Card)," RFID Journal, April 22, 2003, available at http://www.rfidjournal.com/article/articleview/393/1/1/.

One commercial implementation of RFID for locating objects outside the scope of normal supply-chain operations is the SafeTZone® system for locating children or other family members at large theme parks. In this system, people are given a bracelet with an active RFID tag. Readers stationed throughout the park can read the signal from a given bracelet and use triangulation to determine the location of the person. Computer terminals allow parents, for example, to determine the location of family members on a map of the park. Related tracking systems include those marketed by WhereNet, Inc. (Santa Clara, California).

An application of RFID involving locating objects and video information is also found commercially in some amusement parks, where video cameras can photograph people throughout the day to compile video information, using an active RFID label carried by the person to identify the person while videotaping is done by automated cameras. At the end of a visit to the amusement park, the person can choose to purchase a video tape compiled from footage taken during the day.

A recent development in RFID location is ultra wide band (UWB) RFID. As reported in the news item, "First Ultra Wide Band Tags Approved," Smart Labels Analyst, Issue 32, Sept. 2003, pp. 15-16, Parco Wireless (Portland, Maine) has been granted FCC approval for their UWB Precision Asset Location system that uses UWB pulses emitted by active tags to provide two- and three-dimensional location of objects to within a few inches. The system is presently being marketed for asset tracking in hospitals. Though the tags are much larger than standard RFID chips (roughly the size of a wristwatch, weighing over 40 grams each), they are said to provide several advantages, such as an indoor range of about 300 feet. Products and other objects equipped with UWB tags can also be used for the systems described in this paper.

Some concepts for RFID tracking in the home or other environments were recently disclosed in US Patent Publication 20030214387, published Nov. 20, 2003 by G. Thomas. Any of the embodiments therein may be adapted for the purposes discussed in this paper.

Smart Shelves for Object Tracking

An important element of proposed RFID system in retail environments is the ability to track individual items on the shelves in order to keep the shelves properly stocked. Smart shelves can be a valuable tool in achieving this purpose. Smart shelves are instrumented shelves that are associated with one or more RFID readers for locating tagged objects on the shelf. Some concepts are discussed in PCT publication WO 00/65532, "Storage System," published Nov. 2, 2000, by Kevin Ashton, former Director of the Auto-ID Center. Smart shelf units under the name "SmartShelf" have been manufactured by SAMSys Technologies, Inc. (Ontario, Canada). However, there have been several limitations to such systems. Smart shelves in early demonstration trials in Europe and the United States have been both expensive and cumbersome, with multiple stand-alone readers installed at multiple locations along a single shelf to track items at various stations. The use of coaxial cable for these readers has resulted in cluttered equipment around the shelves. Furthermore, these shelf units may not be suitable for end-aisle display units or for use in the storage area, where items may be stored in boxes or on pallets in a disorderly fashion.

As an improvement, advanced smart shelves have been developed in which a single antenna or single array of interconnected antennas with a single reader can be used to determine the location along a shelf. One such technology is that of D.G. Bauer et al., "Intelligent Station Using Multiple RF Antennae and Inventory Control System and Method Incorporating the Same," US Patent Publication 200030174099-A1, published Sept. 18, 2003, filed as US patent application Serial No. 10/338892, assigned to MeadWestvaco Corporation.

Another technology for smart shelves that is said to eliminate the need for coaxial cable at all and provide good resolution on a shelf at low cost is the recirculating phase array antenna system of AWID (Applied Wireless Identification Group, Hollister, California) coupled with their fast look-ahead decay sensing system. Such antenna systems can be provided in roll-to-roll form for easy retrofitting of existing shelves (see Jeffrey Jacobsen, op. cit.). A film provided with the antennas and conductive leads can be provided for rapid placement on the surface of a shelf where it may be hidden under paper or other materials. Associated with the antenna system are additional electronics for signal reading and processing.

Smart shelves can be used as a tool in locating objects in non-retail environments as well. The concept could be extended to homes, for example, with individual rooms having instrumented smart shelves or, by analogy, smart closets, smart attics, smart cupboards, smart drawers, and the like, each associated with one or more readers that can determine the location of tagged objects whenever desired or in real time. For example, the multiple loops in a single antenna from the Bauer et al. patent application (US Patent Publication 200030174099-A1) could be extended to a closet, in which a single reader has multiple antenna loops at various vertical and horizontal locations to provide spatial resolution throughout a closet such as a walk-in closet with multiple shelves at multiple levels.

Combining RFID and Multimedia

Many devices can provide information that could be advantageously associated with RFID codes of individual objects. In fact, one system that we propose combines digital recording devices with RFID equipment to facilitate the process of associating useful information with RFID codes. The associated information can include photographs from digital cameras or other devices such as video-equipped cell phones, digital movies, digitized voice or other audio recordings, animated graphics, and computer files of any kind.

A basic system for archiving of information about an object can include the following steps:

  1. An object is provided with an RFID tag having a unique electronic product code. The tag may already have been associated with the object by a vendor or manufacturer, or the owner may physically attach a tag with a known electronic product code.
  2. One or more types of information about the object is obtained and stored electronically in a database, where it is associated with the electronic product code of the object.
  3. When the object is subsequently scanned, the electronic product code is obtained and used to retrieve the previously stored multimedia information.

The information about an object can include:

We propose that multimedia sources be combined with RFID to enhance the information obtained during the storage or archiving of objects.

Several commercial systems have been developed for combining photos and other information into databases of information about objects, and these can be adapted for use with RFID to further enhance the performance of such systems. For example, Sony and other manufacturers of digital cameras provide camera systems that allow photos of multiple objects to be cataloged and combined with other information provided by a user. Such systems can be adapted to link an electronic product code from an RFID tag with the cataloged photographic information. The electronic product code can serve as a pointer to the cataloged images and other information about the object. Scanning an object can then retrieve the multimedia information, or a database query that retrieves desired information or photos can then be used to determine the electronic product code of the object, which in turn can be used to determine the location of the object.

One business model would include allowing a person to program the system in order to categorize items in their possession that are of sentimental value, attach a passive chip to the article, and add the ID code of the chip to a searchable database of items where it can be linked to other information related to the object. The ID codes can be unique for each item or can simply identify the class or category an item belongs to.

Items tracked can include, by way of example, photos, selected pieces of art (including art from the children in a family), books, scrapbooks, letters, greeting cards, gift items, mementos, awards, trophies, plaques, jewelry, or other items that in the user's opinion are of sentimental or heirloom value. Any other object can also be used, of course, such as medications and medical devices, items of clothing, sports equipment, automotive parts, musical equipment, remote control devices, kitchen utensils, lawn and garden equipment, motor vehicles, bicycles, and the like.

For sentimental items, family members, for example, could use a scanner to scan the RFID tag of an item, and then instantly access information associated with that code from a database logging the sentimental item. In one example, the process of scanning an object may automatically play a slideshow or other video tying the item to a memorable family event, and/or link to the family Website providing related information. An RFID scanner may be built in to a cell phone, PDA, MP3 player, laptop computer, or other portable device capable of playing back sound, video, or other multimedia information in response to identifying an object.

In one example, a wide variety of historical information about an individual, including multimedia files, can be stored to provide an overview of the individual's life or to provide user-selected information about the individual's life. An RFID tag in an object associated with the individual may then serve as a pointer to the stored information so that a person with a suitable viewing device and RFID scanner can gain access to the stored information when in the presence of the object, wherein access to the information may further require use of a password or may be require that an authorized user be identified via a personal RFID tag or with biometrics or other means. Thus, an authorized user may approach an object and gain access to a wide variety of information about the person associated with the object. In one case, the object may be a tombstone or mausoleum for a deceased individual who wished to provide multimedia nostalgic displays to authorized relatives and descendants, with different subsets of files being accessible by different users. In another case, the object may be memorabilia in a museum in which patrons carry portable display devices that provide the option to access detailed information about individuals (or about the objects themselves) when desired.

In general, the ability to link a wide variety of information to an object via an RFID electronic product code can greatly enhance the ability of individuals and groups to maintain information about important items. For example, compilations of family history can be greatly enhanced by active links between objects and historical information (e.g., display of a family tree, replaying of a recorded video, display of photographs associated with the object, etc.).

RFID Tag Dispensers

In terms of hardware, a user may use separate devices for attaching RFID tags and creating multimedia information, or such devices can be integrated into one handheld unit, such as a digital video camera combined with an RFID scanner/writer, an RFID tag dispenser, a GPS device for recording location, and communication means for sending RFID information and associated multimedia information (including position, time, photos, movies, sound recordings, etc.) to a database for archiving. The communication means could be a wireless connection to a wide area network or the Internet or an intranet, or could be a cable-based connection (e.g., a USB-2 port) for downloading stored information to a network or computer. One example of a tool that could be used in the scope of the proposed system is the Intermec Intellitag® IP3 RFID reader and writer, which can be an accessory for Intermec 700 Series Color mobile computers.

In one embodiment, a RFID-dispensing device is used to provide RFID tags having a known electronic product code for attachment to a selected object. The dispensing device may contain a plurality of RFID tags and may include a scanner to read the RFID tag code as it is dispensed (tags may be held in an RF-shielded container prior to removal of an individual tag for attachment to an object). The tag may be provided with an adhesive backing (e.g., a roll of RFID labels with pressure sensitive adhesive backings and release paper liners) for attachment to an object, or a glue such as an isocyanate adhesive, epoxy, or a hotmelt may be used to attach the tag to an object. Such glue may be provided from the RFID dispensing device or added manually to attach the chip. One example of a hotmelt system for attaching RFID tags to porous objects is that of WoodWelding SA (Zürich, Switzerland), described in SmartPackaging Journal, Issue 15, Nov. 2003, p. 9 (see http://www.idtechex.com/smartpackaging/backspj/spj_nov03.pdf). Related PCT publications include WO 00/79137, "Integral Joining," WO 01/89809, "Sealing," and WO 02/69817, "Implants, Device and Method for Joining Tissue Parts."

The RFID-dispensing device may also include or be cooperatively associated with a recording device for recording sound or images, such as a PDA, a digital camera, a digital camcorder, a tape recorded, a cell phone, including cell phones with video cameras, and the like, in order to record information about the object when the RFID tag is dispensed and attached to the object. Alternatively, the RFID tag may have been previously attached to the object (e.g., during manufacture or by a manufacturer or retailer, or by the user) or may be attached after recorded information has been obtained.

Finding a Requested Object

In many cases a user may want to find an object whose present location has been forgotten. Finding the object, once it has been tagged with RFID and cataloged, can be enabled in several ways. When the location of the object has not changed since its position was last recorded in a database, a simple query of the object's location can provide the location information from the database. The location may automatically be associated with a map, verbal or printed directions, instructions to an automated retrieving device or robot to bring the object to the user or a predetermined pick-up location, etc.

When the location of the object is not presently known, a radio signal can be sent by one or more readers to determine if the object is in range. If so, a variety of strategies can then be used to locate the object, including the use of directional signals, RFID triangulation using a plurality of readers, and the like. In one embodiment, the RFID tag includes an LED light that flashes to allow the user to visually determine the location of the object. Yoshikawa Corporation of Japan produces an RFID LED indicator that flashes in response to a search request, a technology that has been implemented in some Japanese medical libraries.

Once the object has been found, associated information such as multimedia files may be retrieved and played or displayed for the user. Display may be on a handheld device, a display panel at a fixed position, a flexible display panel associated with the object, etc., or may involve audio sound played for the user from conventional speakers or focused sound audible by the user only, such as sound provided by hypersonics. Hypersonic signals in which a narrow beam of sound is targeted to an individual, can be generated using systems from American Technology (San Diego, California), as described more fully in a white paper, "Theory, History, and the Advancement of Parametric Loudspeakers: A Technology Overview," by James J. Croft and Joseph O. Norris, Revision D, American Technology Corporation, San Diego, California, 2002, available at http://www.atcsd.com/pdf/HSSWHTPAPERRevD.pdf. Applications of hypersonics are illustrated at http://www.popsci.com/popsci/hometech/article/0,12543,351353,00.html.

Summary

RFID technology can be applied outside of normal commercial environments to help individuals and other groups to track objects and retrieve information associated with the items. The ability to link multimedia information with personal items in a household or other setting may provide unique ways to preserve historical and nostalgic information, and to improve the storage and handling of items.

Appendix: RFID Basics

Basic principles of RFID technology are given by Raghu Das, "RFID Explained: An Introduction to RFID and Tagging Technologies," white paper from IDTechEx Ltd. available at www.idtechex.com, dated 2003, as viewed Aug. 19, 2003. The author defines RFID as follows:
Radio Frequency Identification (RFID) is the use of radio frequencies to read information on a small device known as a tag. . . Radio frequency Identification (RFID) is a term used for any device that can be sensed at a distance by radio frequencies with few problems of obstruction or misorientation. The origins of the term lie in the invention of tags that reflect or retransmit a radio-frequency signal. In its current usage, those working below 300Hz and those working above 300MHz, such as microwave (GHz) tags, are included. For example, one type of chipless tag works at only a few hertz and Inkode chipless taggants operate at around 20-25 GHz. Higher frequencies such as visible and infrared devices are excluded as these systems have very different properties and are frequently sensitive to obscuration, heat, light and orientation.

The term "tag" is used to describe any small device--shapes vary from pendants to beads, nails, labels or microwires and fibres that can be incorporated into paper and even special printed inks on, for example, paper.

Examples of potential applications for smart chips attached to products and wireless communication systems are described by C.R. Schoenberger in "The Internet of Things," Forbes, March 18, 2002, pp. 155-160. Further information on these technologies is provided at http://www.mccombs.utexas.edu/news/magazine/01f/alien.asp and http://www.mindfully.org/Food/The-Code.htm, and more technical information has been provided by MIT's Auto-ID Labs (formerly the Auto-ID Center), Cambridge, Mass. Useful information from the Auto-ID Labs can be accessed from www.autoidlabs.org/ and other information can be obtained at http://archive.epcglobalinc.org/aboutthetech.asp. See also "Toward the 5 Tag" by Sanjay Sarma, Auto-ID Center, Nov. 2001, available at http://www.autoidlabs.org/whitepapers/mit-autoid-wh-006.pdf, and "Integrating the Electronic Product Code (EPC) and the Global Trade Number (GTIN)," by David L. Brock, Auto-ID Center , Nov. 2001, available at http://www.autoidlabs.org/whitepapers/mit-autoid-wh-004.pdf.

An overview of the history of RFID is given by Jeremy Landt in "Shrouds of Time: The History of RFID," AIM (Association for Automatic Identification and Data Capture Technologies), Pittsburgh, Pennsylvania, Oct. 1, 2001, available at http://www.aimglobal.org/technologies/rfid/resources/shrouds_of_time.pdf.

RFID chips can be used to track products grouped in various hierarchies: (1) individual items or single packages containing multiple items for consumer purchase; (2) cartons or cases of multiple items; (3) pallets of multiple cartons or cases; and (4) loads (e.g., truckloads, shiploads, or railcar loads) of multiple pallets. The products at each of these levels may be assigned an RFID label that is associated with information pertaining to at least one adjacent hierarchical level. For example, an RFID label on a pallet may be associated in a database with the RFID labels for each carton on the pallet, or may be associated with data pertaining to the RFID label from the truckload.

RFID tags of any known type may be used, including:

While RFID tags typically include a semiconductor chip associated with an electronic code, chipless RFID technologies are also known.

Examples of low-cost technologies for producing chip-based RFID systems listed by Raghu Das (2003) include:

For chipless RFID, Das lists the following as available low-cost RFID technologies:

Transistor-based chipless circuits can include laminar transistor circuits, including polymer film circuits such as those of Plastic Logic, Inc. or Philips Research Laboratories, thin film silicon, bioelectronics, etc. Magnetic wire and fiber systems for chipless RFID can include the products of MXT (Canada), HID (US), British Technology Group (UK), Fuji Electric (Japan), REMOSO Development (Netherlands), and Advanced Coding Systems (Israel). Laminar transistorless circuits can include diode circuits, printed electronics, EM tags of ACS, surface acoustic wave technology such as that of RF SAW, Inc., and LC arrays (swept RF) such as the devices of CWOSRFID (US) and Lintec (Japan), Miyake (Japan), Checkpoint (US), MIT Medialab (US), the rewritable chipless tag of Navitas (Japan). Thin magnetic films for chipless RFID can include conventional magnetics for non-contact reading, or the films of Flying Null (UK), 3M Intelligent Transportation Systems (US), SCipher TSSI (UK), etc. Magnetic assembly can also be used, such as the technologies of Scientific Generics (UK). The self-generation RFID technology of Siemens Roke Manor Research can also be employed.

Any of these chips may be read-only chips, which include a fixed electronic code, or they may be read-write chips, which allow new information to be added. The chips may also be associated with sensors to read sensor information and transmit a signal responsive to the information, such as a value from a biosensor. Exemplary smart labels including RFID technology associated with a sensor are the active labels of KSW Microtec (Dresden, Germany), including TempSens® active smart labels for measuring and recording temperature. KSW Microtec also offers smart labels produced by flip chip assembly methods.

RFID tags can take many physical formats, such as a microchip from 30 to 100 microns thick and from 0.1 to 1 mm across, joined to a minute metal antenna such as the Hitachi 2.45 GHz Mew chip, or they can be in the form of deposited alloys 0.5 to 5 microns thick on a 20 micron polyester ribbon 1 mm across as used in some banknote security ribbons. Another form is the "Coil-on-Chip" system from Maxell (Tokyo, Japan), which is a 2.5 mm square IC with an antenna coil mounted directly on the chip. The chip is a read-write chip with 108 bytes of storage.

In addition, related devices such as the PENI tag of the University of Pittsburgh can also be considered a means for identifying objects wirelessly.

Exemplary RFID vendors include Matrics, Intermec, Alien Technology, Philips Semiconductor, and Texas Instruments. Manufacturing can be done by robotic techniques (e.g., "flip-chip"/"pick and place" techniques), fluidic self-assembly (FSA), the Philips "I-connect" method or the Philips "vibratory assembly" method, the Matrics PICA system (Parallel Integrated Chip Assembly, as described in the news item "New High-Speed RFID Tag Machine," RFID Journal, Sept. 19, 2003, available online for subscribers at http://www.rfidjournal.com/article/articleview/586/1/1/) or other known processes. (See also L. Frisk, J. Jarvinen, and R. Ristolainen, "Chip on Flex Attachment with Thermoplastic ACF for RFID Applications," Microelectronics Reliability, 42(9-11): 1559-1562 (Sept.-Nov. 2002)). Also of potential use for tracking and finding objects is the "mu-chip" of Hitachi with a built-in antenna on a sub-millimeter chip having a 128-bit serial number, as described by Jonathan Collins, "Hitachi Unveils Integrated RFID Tag," RFID Journal, Sept. 4, 2003, available at http://www.rfidjournal.com/article/articleview/556/1/1/. Exemplary RFID reader manufacturers include Intermec Technologies, Symbol Technologies, Matrics, AWID (e.g., their multi-protocol reader that can operate at various frequencies), and others. Software systems to support RFID systems are provided by IBM Global Services (which has acquired PriceWaterhouseCoopers), Texas Instruments, Manhattan Associates, and others. Printed RFID labels can be made using equipment from Zebra Technologies and other vendors.

Readers may also be integrated into or added onto a laptop, a PDA device, a cell phone, or other electronic device. Suitable readers may include the readers of AWID or the RFID reader on a compact flash card marketed by Syscan International for reading 13.56 MHz ISO-compliant tags or for other frequencies, as described in the news item, "Get RFID Readers in a Flash (Card)," RFID Journal, April 22, 2003, available online for subscribers at http://www.rfidjournal.com/article/articleview/393/1/1/.

Chip-based RFID systems need not be limited to silicon chips, but can also include printed electronics, particularly polymer electronics (organic electronics) such as organic field effect transistors (OFETs), and other technologies. Principles of polymer electronics are given by J. M. Shaw and P. F. Seidler, "Organic Electronics: Introduction," IBM Journal of Research and Development, Vol. 45, No. 1, 2001 (http://www.research.ibm.com/journal/rd/451/shaw.html). See also PCT publication WO 99/19883, published April 22, 1999 by S. Babinec et al. of Dow Chemical. A representative manufacturer of printed electronics technology is Precisia, LLC (Ann Arbor, Michigan), a business unit launched by Flint Ink (Ann Arbor, Michigan). Precisia, LLC produces printed electronics for RFID systems, including smart packaging, lighting, and displays. Conductive inks manufactured by Precisia, LLC including conductive particles of silver or carbon have been proposed for use in printed RFID antennas. Such inks can be applied by screen printing, flexographic printing, lithographic printing, gravure printing, ink-jet printing, and the like. Plastic Logic (Cambridge, England) is another firm producing printable electronics suitable for RFID applications.

Other components associated with RFID systems can also include polymer electronics or printed electronics. For example, display graphics can include organics LEDs (OLEDs), printed electroluminescent displays, printed organics application specific integrated circuits (organic ASICs), polymer thin film transistors (pTFTs), the light-emitting polymers (LEPs) of Dow Corporation (see www.lumation.com and Apply. Phys. Letters, Vol. 77, 2000, p. 406), and the like.

Power sources may include printed batteries, such as those produced by PowerPaper (Einat Israel--see www.PowerPaper.com) or Cymbet Corp. (Elk River, Minnesota--see http://www.rfidjournal.com/article/view/94), or may rely on energy harvesting techniques that convert RF energy into useful electrical energy.

RFID tags can be assembled using flip chip technology, in which chips from an RFID wafer are inverted and placed in contact with an antenna. Exemplary processes include the Matrics PICA process for chip attachment to the antenna.

The RFID system may follow the systems proposed by the MIT Auto-ID Center, including the use of an electronic product code (EPC); a Savant system to manage the codes being read with a distributed architecture and processes such as data smoothing, reader coordination, data forwarding, data storage, and task management; and Object Name Service (ONS) for matching EPC information to item information, typically using a Domain Name Service (DNS) to route computers to Internet sites; and Physical Markup Language (PML) to describe information about a product.

Other vendors of integrated RFID systems or other tools for RFID include CheckPoint Systems, Tyco Sensormatic, Escort Memory Systems, Psion Teklogix (particularly for software systems to assist in logistics), SAMSys Technologies, Savi Technology, SCS Corporation, TAGSYS, ThingMagic LLC, and others. Supply-chain software can be provided by Crimson Software, Descartes Systems, EXE Technologies, Globe Ranger, Manhattan Associates, IBM Global Services, SAP, and others. RFID readers include those of Alien Technology, Matrics, Intermec, iPico, and AWID (Applied Wireless Identification Group, Hollister, California).

The tag may be provided by the manufacturer, a vendor, or others, and may be embedded in the object, attached to the surface of the object by a label or adhesive means, or be otherwise physically associated with the object. The RFID tag may have a unique electronic product code or other code, or optionally may include more extensive information.

Finally, an alternative to typical low-range readers is to use long-range readers with directional antennas that sweep selected areas to identify objects based on their RFID code. For such systems, highly sensitive electronics can be used to resolve faint signals at larger distances. By using advanced antennas in particular, RFID tags may, in some cases, be read from larger distances than previously recognized. The US military, for example, has developed sensitive electronics to extend the read range of passive RFID tags to large distances, as described in the article, "RFID Sensors: From Battlefield Intelligence To Consumer Protection," RFID Journal, Aug. 12, 2002, available online at http://www.rfidjournal.com/article/view/182. Such ultra-sensitive radio frequency receivers rely on filtering systems to separate the RFID signal from background noise.

One antenna technology that may be particularly useful in amplifying weak signals and determining the direction of a radio signal source is smart antenna technology, such as adaptive antenna arrays including a plurality of antennas cooperatively associated with processors that continually readjust the radio signals from each of the antennas to create radio systems with extremely precise directionality and the ability to greatly amplify detected signals. Basic information about such smart antenna systems is provided by Martin Cooper in "Antennas Get Smart," Scientific American, Vol. 289, No. 1, July 2003, pp. 49-55. Further information is given by Martin Cooper and Marc Goulburg, "Intelligent Antennas: Spatial Division Multiple Access," 1996 Annual Review of Communications, pp. 999-1002 (see www.arraycomm.com/Company/spatial_division.pdf); in Joseph C. Liberti and T.S. Rappapport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, New York: Prentice Hall, 1999; and in various papers available at www.arraycomm.com/Company/white_papers.html. By way of example, manufacturers of adaptive antenna arrays include ArrayComm (San Jose, California) and Lucent Technologies (Murray Hill, New Jersey). Other antenna arrays can also be used, such as switched-beam arrays. Other beam-forming and beam steering technologies can be applied as well, such as the directional steerable antenna systems of Antenova Ltd. (Cambridge, England, see www.antenova.com/).


RFIG Lamps: Interacting with a Self-describing World via Photosensing Wireless Tags and Projectors - a technology for improving the use of RFID to locate objects, developed at the Mitsubishi Electric Research Laboratories.

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