Method of Assigning and Deducing the Location of Articles Detected by Multiple Rfid Antennae

• US 20080266092A1
• Filed: 05/06/2005
• Published: 10/30/2008
• Est. Priority Date: 05/07/2004
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Meadwestvaco (WestRock Company)
• Inventors: Bauer, Donald G., Rasband, Paul B., Jones, Matthew A., Campero, Richard J., Spelden, Richard H.
• Granted Patent: US 7,932,830 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G01S 13/82 wherein continuous-type signals are transmitted
• CPC Class Codes: G06K 17/0012 with more than one selection steps, e.g. selection of a record carrier from a selected compartment of a compartmented storage storage devices for articles B65G1/0407
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22

Abstract

In accordance with preferred embodiments or the invention, a method (and corresponding apparatus) is provided for deducing the location of one or more items or objects to be monitored. In exemplary embodiments, the method (and corresponding apparatus) is implemented in RFID (radio frequency identification) applications (e.g., reading RFID tags at 13.56 MHz and approximately 900 MHz) by deducing the location of an item associated with a unique RFID tag in one or more areas of detection covered by multiple RFID reader antennae.

Claims

1. A method of determining the location of an item, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors, wherein the first detection zone overlaps at least an area of the second detection zone;

designating the overlap area as a virtual detection zone; and

detecting the presence of an item in the virtual detection zone when the item is detected by both the first and second detectors.

2. The method of claim 1, wherein said detecting step detects the presence of an item in the virtual detection zone after the first detector detects the presence of the item at a first time and the second detector detects the presence of the item at a second time.

3. The method of claim 1, wherein said detecting step detects the presence of an item in the virtual detection zone by both the first and second detectors at the same time.

4. The method of claim 1, further comprising adjusting a size of the virtual detection zone by changing power supplied to at least one of the first and second detectors.

5. The method of claim 1, wherein the first and second detectors are RFID reader antennae and said adjusting step comprises increasing the size of the virtual detection zone by increasing the power of at least one of the first RFID antenna and the second RFID antenna.

6. The method of claim 1, wherein said adjusting step comprises the step of decreasing the size of the virtual detection zone by decreasing the power of at least one of the first RFID antenna and the second RFID antenna.

7. The method of claim 1, wherein said adjusting step further comprises reducing the power of the first detector until the item is not detected in the virtual zone;

and resolving the location of the item wherein the item is assigned to the detection zone where it is detected.

8. The method of claim 1, further comprising associating the item with an RFID tag detectable by the first and second detectors.

9. The method of claim 8, further comprising assigning a unique identification number to the RFID tag selected from the group consisting of a manufacturer number, a stock keeping unit number, and a serial number.

10. A method of deducing the location of a plurality of items, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors;

assigning the items to the first detection zone and the second detection zone;

designating the first detection zone and the second detection zone as related zones; and

resolving the location of an item detected in both the first detection zone and the second detection zone by assigning the detected item to the first detection zone or to the second detection zone.

11. The method of claim 10, further comprising pre-assigning items to the first or second detection zones prior to performance of said resolving step.

12. The method of claim 10, wherein an item detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 50% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

13. The method of claim 10, wherein an item detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 66% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

14. The method of claim 10, wherein an item detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 80% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

15. The method of claim 10, further comprising the step of providing a plurality of items each having an RFID tag comprising a unique identification number.

16. The method of claim 10, wherein said step of providing a plurality of items comprises selecting a unique identification number for each RFID tag from the group consisting of a manufacturer number, a stock keeping unit number, and a serial number.

17. A method of assigning the location of a plurality of items, the method comprising the steps of:

designating first and second detection zones respectively associated with first and second detectors;

comparing the number of items detected in the first detection zone and the second detection zone;

determining the number of items detected in both the first detection zone and the second detection zone; and

deducing a location of an item detected in both the first detection zone and the second detection zone based on assignment of the item to one of the first and second detection zones, wherein said deducing step comprises the step of assigning the item to one of the first and second detection zones in accordance with the proportion of the items in the first detection zone compared to the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

18. The method of claim 17, wherein the location of the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 50% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

19. The method of claim 17, wherein the location of the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 66% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

20. The method of claim 17, wherein the location of the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected by only the first detection zone is 80% or greater than the sum of the number of items detected by only the first detection zone and the number of items detected by only the second detection zone.

21. The method of claim 17, wherein the location of 50% the items detected in both the first detection zone and the second detection zone is assigned to the first detection zone if the number of items detected only in the first detection zone is equal to the number of items detected in both the first and second detection zones.

22. The method of claim 17, wherein the total number of items assigned to a detection zone does not exceed a predetermined capacity for the detection zone.

23. The method of claim 17, wherein the predetermined capacity of the detection zone is determined by the area of the detection zone.

24. The method of claim 17, wherein the predetermined capacity of the detection zone is determined by the volume of the detection zone.

25. A method of assigning the location of a plurality of items, the method comprising the steps of:

designating first and at least a second detection zone respectively associated with first and at least a second RFID reader antennae;

detecting the items with an RFID reader antenna;

comparing the number of items detected in the first detection zone and the at least a second detection zone;

identifying a joint item detected in both the first detection zone and the at least a second detection zone; and

assigning a first percentage of the joint item to the first detection zone and a second percentage of the joint item to the at least a second detection zone.

26. The method of claim 25, further comprising detecting the joint item in a third detection zone.

27. The method of claim 25, wherein the first percentage of the joint item is 50% if the number of detection zones is two.

28. The method of claim 26, wherein the first percentage of the joint item is 33% if the number of detection zones is three.

29. The method of claim 25, wherein the first percentage of the joint item is 50% for the first detection zone and the second percentage of the joint item is 25% for a second detection zone.

30. The method of claim 26, where the first detection zone is adjacent to the second detection zone and the third detection zone.

31. The method of claim 26, wherein the percentage of the location is 100% for the first detection zone, 0% for the second detection zone, and 0% for the third detection zone.

32. The method of claim 31, where the first detection zone is adjacent to the second detection zone and the third detection zone.

33. A method of confirming that an item is missing, the method comprising the steps of:

providing a plurality of items wherein each item is associated with an RFID tag;

designating a detection zone associated with an RFID reader antennae;

detecting the presence of an item in the detection zone at a first time by polling the RFID reader antenna;

determining if the item is present during at least a second time, wherein if the item is not present during the at least second time, the RFID reader antenna is polled a predetermined number of times; and

confirming that the item is missing if the item is not detected after the RFID reader antenna is polled for the predetermined number of times.

34. The method of claim 33, wherein the predetermined number of times is increased if the packaging of the item interferes with the polling of the RFID antenna.

35. A method of reporting information regarding detection of at least one item that is associated with an RFID tag, the method comprising the steps of:

detecting an item during a first read cycle;

reporting information regarding detection of the item during the first read cycle;

detecting the item during subsequent read cycles; and

suppressing information regarding detection of the item during a predetermined number of subsequent read cycles.

36. The method of suppressing data as recited in claim 35, wherein said step of detecting the item during subsequent read cycles comprises the step of detecting the item during a period less than a predetermined length of time after the first read cycle;

and wherein the step of suppressing information comprises the step of suppressing the information regarding detection of the item during the subsequent read cycles for the predetermined length of time.

37. The method of suppressing data as recited in claim 35, wherein said steps of detecting an item during a first read cycle and detecting the item during subsequent read cycles are both performed using a first reader antenna.

38. The method of suppressing data as recited in claim 35, wherein said steps of detecting an item during a first read cycle and detecting the item during subsequent read cycles are performed using a first reader antenna and second reader antenna, respectively.

39. A method of deducing the location of a plurality of items, the method comprising the steps of:

providing a plurality of items wherein each item is associated with an RFID tag;

designating first and second detection zones respectively associated with first and second RFID reader antennae;

identifying the items in the first detection zone and the second detection zone with the first and second RFID reader antennae, respectively;

reading the information in the RFID tags;

determining the similarity of the items detected in the first detection zone and the second detection zone according to information in the RFID tags; and

assigning the location of the plurality of items according to the similarity of the items detected in the first detection zone and the second detection zone.

40. The method of claim 39, wherein the information in the RFID tags is selected from the group consisting of the SKU number and the UPC code.

41. A method of deducing the location of a plurality of items, the method comprising the steps of:

providing a plurality of items wherein each item is associated with an RFID tag;

designating a detection zone associated with an RFID reader antenna;

detecting the items in the detection zone with the RFID antenna reader;

determining the distance of the items in the detection zone from the RFID antenna; and

assigning the location of the items to the detection zone if the distance of the item from the RFID antenna is less than a predetermined distance.

42. A method of deducing the location of a plurality of items, the method comprising the steps of:

providing a plurality of items wherein each item is associated with an RFID tag;

designating a detection zone associated with an RFID reader antenna;

detecting the items in the detection zone with an RFID antenna reader;

determining the area occupied by the items in the detection zone; and

assigning the location of the items to the detection zone if the area occupied by the item is less than a predetermined area.

43. A method of deducing the location of a plurality of items, the method comprising the steps of:

providing a plurality of items wherein each item is associated with an RFID tag;

designating a detection zone associated with an RFID reader antenna;

detecting the items in the detection zone;

determining the volume occupied by the items in the first detection zone;

assigning the location of the plurality of items to the detection zone if the volume occupied by the items is less than a predetermined volume.

44. A system for reading a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae capable of detecting the RFID tags; and

a plurality of RFID readers coupled to the plurality of RFID reader antennae for detecting items with a first RFID reader antenna and at least a second RFID reader antenna; and

a controller for identifying items detected by the first RFID reader antenna and at least a second RFID reader antenna and determining the location of the items.

45. The system of claim 44, wherein the location of the items detected by both the first RFID reader antenna and the at least a second RFID reader antenna is determined to be in proximity to the first RFID reader antenna and the at least a second RFID reader antenna.

46. The system of claim 45, wherein the location of the items detected by both the first RFID reader antenna and the at least a second RFID reader antenna is determined to be in between the first RFID reader antenna and the at least a second RFID reader antenna.

47. The system of claim 44, wherein the location of the items is assigned according to the proportion of RFID tags detected by the first RFID reader antenna compared to the proportion of RFID tags detected by the second RFID reader antenna.

48. A system for determining the location of a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae, each RFID antenna having a detection zone, wherein the detection zone of a first RFID antenna overlaps the detection zone of a second RFID antenna forming a virtual detection zone; and

at least one RFID reader coupled to the plurality of RFID reader antennae for detecting an item in the virtual detection zone when the presence of the item is detected by both the first and second RFID antennas.

49. A system for deducing the location of a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae, each RFID antenna having a detection zone wherein a first detection zone and at least a second detection zone are related zones if an item is detected in both the first detection zone and the at least a second detection zone; and

at least one RFID reader coupled to the plurality of RFID reader antennae for detecting an item wherein the location of an item detected in the related zone is assigned to the first detection zone or to the at least a second detection zone.

50. A system for assigning the location of a plurality of items comprising RFID tags, the system comprising:

a plurality of RFID reader antennae, each of the plurality of RFID antennae having a first detection zone and at least a second detection zone; and

at least one RFID reader coupled to the RFID reader antennae for determining the number of items within the first detection zone and the at least a second detection zone, wherein the number of items within the first detection zone is compared to the number of items within the second detection zone and the deduced location of the items is assigned according to the proportion of the number items in the first detection zone compared to the number of items in the at least a second detection zone.

51. A system for reading items comprising RFID tags, the system comprising:

a plurality of items each having an RFID tag and each RFID tag having a unique identification number;

a plurality of RFID reader antennae for reading the RFID tags wherein the RFID reader antennae have a first detection zone and at least a second detection zone;

at least one RFID reader for reading data from the RFID tags within the first detection zone and the at least a second detection zone; and

a controller for activating the plurality RFID reader antennae to read the RFID tags, determining the location of the items, and storing the data in a local database.

52. The system of claim 51, wherein the location of the items is in the first detection zone or the at least a second detection zone.

53. The system of claim 51, wherein the location of the items is in the first detection zone when said at least one RFID reader detects the item in at least a first predetermined number of read attempts out of a total number of read attempts.

54. The system of claim 53, wherein the first predetermined number of read attempts for which said at least one RFID reader determines that the item is in the first detection zone is 80% of the total number of read attempts made by said at least one RFID reader.