Electronic article surveillance deactivator with multiple label detection and method thereof

• US 7,973,660 B2
• Filed: 07/23/2008
• Issued: 07/05/2011
• Est. Priority Date: 07/23/2008
• Status: Active Grant

• Current Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Original Assignee: Sensormatic Electronics LLC (Johnson Controls International plc)
• Inventors: Hall, Stewart E.
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): LAU, HOI CHING
• Application Number:
  US12/178,194
• Publication Number:
  US 20100019904A1
• Time in Patent Office: 1,077 Days
• Field of Search: 340/572.1, 340/572.3, 340/573.4, 340/521, 340/541, 340/568.1, 340/10.364, 340/10.42, 235/383, 235/481, 235/385, 235/375, 235/382.5, 455/83
• US Class Current: 340/568.1
• CPC Class Codes: G08B 13/2485 Simultaneous detection of multiple EAS tags

Abstract

A method and system for preventing simultaneous deactivation of multiple electronic article surveillance (“EAS”) tags. An RF pulse is transmitted within an EAS interrogation zone to induce a response from at least one EAS tag placed within the interrogation zone. The response of the at least one EAS tag is received. A presence of more than one EAS tag is determined by evaluating a frequency response curve corresponding to the response.

Claims

1. A method for determining a presence of multiple electronic article surveillance (“

EAS”

) tags within an interrogation zone, the method comprising;

transmitting an electromagnetic pulse within an EAS interrogation zone to induce a response from at least one EAS tag placed within the interrogation zone;

receiving the response of the at least one EAS tag; and

determining a presence of more than one EAS tag by evaluating a frequency response curve corresponding to the response, determining a presence of more than one EAS tag includes determining that the frequency response curve contains more than one peak, and evaluating the frequency response curve corresponding to the response includes;

calculating a frequency peak separation between the more than one peaks; and

determining that the frequency peak separation is greater than a predetermined value.

2. The method of claim 1, wherein determining that the frequency response contains more than one peak includes applying a fast Fourier transform filter to the received frequency response.

3. The method of claim 1, further comprising, responsive to determining that the separation is less than a predetermined value, deactivating an EAS tag within the interrogation zone.

4. The method of claim 1, further comprising:

generating an electromagnetic field within the interrogation zone; and

applying a DC bias current to the electromagnetic field.

5. The method of claim 1, further responsive to determining the presence of more than one EAS tag, further includes triggering a video recording system to capture a video image of the interrogation zone.

6. The method of claim 1, further responsive to determining the presence of more than one EAS tag, instructing a video recording system to flag a captured video image of the interrogation zone corresponding to a time when the presence of more than one EAS tag was detected.

7. The method of claim 1, further comprising responsive to determining the presence of more than one EAS tag, inhibiting EAS tag deactivation.

8. An electronic article surveillance (“

EAS”

) tag deactivator for deactivating at least one EAS tag, the EAS tag deactivator comprising;

a transceiver operable to;

transmit an electromagnetic pulse within an EAS interrogation zone to induce a response from the at least one EAS tag placed within the interrogation zone; and

receive the response of the at least one EAS tag; and

a controller communicatively coupled to the transceiver, the controller operable to;

determine a presence of more than one EAS tag by evaluating a frequency response curve corresponding to the response, determining a presence of more than one EAS tag includes determining that the frequency response curve contains more than one peak;

calculate a frequency peak separation between the more than one peak; and

determine that the frequency peak separation is greater than a predetermined value.

9. The EAS tag deactivator of claim 8, wherein the controller is further operable to apply a fast Fourier transform filter to the received response, wherein results of the Fourier transform filter application are used to determine whether the frequency response curve contains more than one peak.

10. The EAS tag deactivator of claim 8, wherein responsive to determining that the separation is not greater than a predetermined value, the controller is further operable to deactivate an EAS tag within the interrogation zone.

11. The EAS tag deactivator of claim 8, wherein responsive to determining the presence of more than one EAS tag, the controller is further operable to inhibit EAS tag deactivation.

12. The EAS tag deactivator of claim 8, further comprising:

an electromagnetic field generator operable to generate an electromagnetic field within the interrogation zone, the electromagnetic field having a DC bias.

13. The EAS tag deactivator of claim 8, further comprising:

a communication interface communicatively coupled to the controller, the communication interface operable to, further responsive to determining the presence of more than one EAS tag, trigger a video recording system to capture a video image of an area surrounding the EAS tag deactivator.

14. A security system for preventing theft of merchandise, the security system comprising:

a plurality of electronic article surveillance (“

EAS”

) tags; and

an EAS tag deactivator operable to;

transmit an electromagnetic pulse within an EAS interrogation zone to induce a response from at least one EAS tag placed within the interrogation zone;

receive the response of the at least one EAS tag;

determine that the response contains more than one peak in a frequency response curve corresponding to the response; and

evaluate the frequency response curve of the response to determine a presence of more than one EAS tag, evaluating the frequency response curve of the response includes;

calculating a frequency peak separation between the more than one peaks; and

determining that the frequency peak separation is greater than a predetermined value.

15. The security system of claim 14, further comprising:

a database communicatively coupled to the EAS tag deactivator, the database operable to store at least one incident report including information relating to determining that the frequency response contains more than one peak.

16. The security system of claim 14, further comprising:

a video recording system communicatively coupled to the EAS tag deactivator, the video recording system operable to;

capture a video image of an area surrounding the EAS tag deactivator corresponding to a time when the EAS tag deactivator was inhibited from operating; and

flag the captured image for future inspection.