Locating system for items having RFID tags

• US 7,741,967 B2
• Filed: 02/13/2006
• Issued: 06/22/2010
• Est. Priority Date: 02/13/2006
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Valeriano, Francisco M., Kuo, Amos Y., Matsunaga, Sabrina Pui-Wah
• Primary Examiner(s): Zimmerman; Brian A.
• Assistant Examiner(s): Nguyen; Nam V
• Application Number:
  US11/352,674
• Publication Number:
  US 20070188342A1
• Time in Patent Office: 1,590 Days
• Field of Search: 340/539.11, 340/539.13, 340/539.21, 340/573, 340/457, 340/825.49, 340/10.1, 455/456.1, 370/328, 235/385, 235/375, 235/383
• US Class Current: 340/539.11
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations

Abstract

A locating system for an archive having multiple objects stored therein includes an RFID reader device having an RFID reader to detect and read RFID tags on the objects. A central processing unit includes a database to store information on each object in the archive, a location engine operating system in communication with the RFID reader device, and a data structure to store a relative position of each object in the archive relative to each other object in the archive. A method of locating an object within an archive containing multiple objects includes carrying an RFID reader device through the archive. The RFID reader device queries each RFID tag for the identifier associated with the RFID tag and determines whether each identifier is an old identifier stored in a memory or a new identifier not stored in the memory. If one or more of the identifiers is a new identifier, a linkage is defined between each object associated with a new identifier and each other object within the range of the RFID reader device. Each linkage is saved in a data structure and each new identifier is stored in the memory.

Claims

1. A method of locating an object within an archive containing a plurality of objects, each of the objects including an RFID tag having a unique identifier, the method comprising:

moving an RFID reader device relative to the archive, the RFID reader device having an RFID reader adapted to detect and read the RFID tags of the objects, the RFID reader having a range for detecting and reading the RFID tags;

determining whether there are any RFID tags within the range of the RFID reader;

querying each RFID tag sensed by the RFID reader for the identifier associated with the RFID tag;

determining whether the identifier for each RFID tag is an old identifier stored in a memory or a new identifier not stored in the memory, and if one or more of the identifiers is a new identifier;

defining a linkage between each object associated with a new identifier and each other object within the range of the RFID reader device,

saving each linkage in a data structure adapted to store a relative position of each object in the archive relative to each other object in the archive, and

storing each new identifier in the memory,

determining whether any object associated with an old identifier is no longer within range of the RFID reader device;

deleting each old identifier associated with an object that is no longer within range of the RFID reader device from the memory;

comparing the identifiers stored in the memory to the linkages stored in the data structure;

determining that a linkage has been broken when the linkages defined by the identifiers stored in the memory is less than the linkages stored in the data structure for the identifiers stored in the memory; and

determining which object of the broken linkage has been moved.

2. The method of claim 1 wherein the archive also contains at least one fixedly disposed landmark RFID tag, the method further comprising:

determining whether there are any landmark RFID tags within the range of the RFID reader;

querying each landmark RFID tag sensed by the RFID reader for the identifier associated with the landmark RFID tag; and

determining whether the identifier for each landmark RFID tag is an old identifier stored in a memory or a new identifier not stored in the memory, and if one or more of the identifiers is a new identifier;

defining a linkage between each landmark RFID tag associated with a new identifier and each object within the range of the RFID reader device,

saving each linkage in the data structure, and

storing each new identifier in the memory.

3. The method of claim 2 further comprising;

determining whether any landmark RFID tag associated with an old identifier is no longer within range of the RFID reader device; and

deleting each old identifier associated with a landmark RFID tag that is no longer within range of the RFID reader device from the memory.

4. The method of claim 1 further comprising:

entering a search criteria for an object to be found into the RFID reader device;

querying each RFID tag sensed by the RFID reader for the identifier associated with the RFID tag;

querying the data structure for linkages connecting the objects in the range of the RFID reader to the object to be found;

computing a shortest distance to the object to be found; and

displaying the distance on an output mechanism of the RFID reader device.

5. The method of claim 4 further comprising moving in a first direction into the archive while observing the output mechanism of the RFID reader device and

moving in the first direction if the distance displayed on the output mechanism decreases;

or

moving in a second direction if the distance displayed on the output mechanism increases.

6. The method of claim 5 further comprising visually scanning for the object to be located when the distance displayed on the output mechanism equals zero.

7. The method of claim 1 wherein determining the object that has been moved comprises:

comparing a listing of the identifiers associated with the objects of the linkages stored in the data structure, for the identifiers stored in the memory;

identifying the identifier of the listing that is missing from the memory; and

classifying the object having a linkage, stored in the data structure, with the object associated with the missing identifier as a carried object.

8. The method of claim 1 further comprising deleting the broken linkage from the data structure.