HK1149108B - Electronic article surveillance system neural network minimizing false alarms and failures to deactivate - Google Patents

Description

Electronic article surveillance system neural network that minimizes false alarms and deactivation failures

Technical Field

The present invention relates generally to electronic security systems, and in particular, to an improved electronic article surveillance ("EAS") system and method for reducing false alarms.

Background

Electronic article surveillance ("EAS") systems are detection systems that allow identification of markers or tags within a given detection zone. EAS systems have many uses, but they are most often used as security systems to prevent theft of merchandise in stores or removal of property from office buildings. EAS systems come in many different forms and utilize several different technologies.

A typical EAS system includes an electronic detection unit, a tag and/or label, and a detacher or deactivator. For example, the detection unit may be formed as a base unit, buried under a floor, mounted on a wall, or hung from a ceiling. The detection units are typically placed in high traffic areas such as entrances and exits of stores or office buildings. The tags and/or labels have particular characteristics and are specifically designed to be affixed to or embedded in merchandise or other objects sought to be protected. When an active tag passes through the tag detection zone, the EAS system sounds an alarm, a light is activated and/or some other suitable alarm device is activated to indicate that the tag has been removed from the designated zone.

Common EAS systems operate these same general principles using either transceivers, each of which can transmit and receive, or separate transmitters and receivers. Typically, the transmitter is placed on one side of the detection zone and the receiver is placed on the opposite side of the detection zone. The transmitter generates a predetermined excitation signal in the tag detection zone. In the case of retail stores, this detection zone is typically formed at the exit. When an EAS tag enters the detection zone, the tag has a characteristic response to the excitation signal, which can be detected. For example, the tag may respond to the signal sent by the transmitter by using a simple semiconductor junction, a tuned circuit consisting of an inductor and capacitor, soft magnetic strips or wires, or a vibrating acousto-magnetic ("AM") resonator. For example, an "AM" tag is a device that exhibits particular responsiveness when activated and deactivated. When activated, an AM tag resonates and transmits a signal at a resonant frequency when excited by an interrogation signal of a particular frequency. The receiver then detects this characteristic response. The performance of "deactivated" AM tags results in the inability to transmit signals at the resonant frequency. By design, the characteristic response of the tag is unique and unlikely to be produced by natural environments.

A consideration in designing and using such EAS systems is to minimize the occurrence of false alarms that may either cause confusion to users of the EAS system, such as retail stores, or produce annoying and disruptive alarm signals when no one is passing through the store's EAS system. There are many types of false alarm signals, including a "false" alarm that occurs when a shopper passes through an EAS system without holding any tagged or protected merchandise but still raises an alarm. Yet another more specific type of false alarm signal is a "merchandise" alarm, which occurs when a shopper carries merchandise through an EAS system that is unprotected, but exhibits the characteristics of a functioning tag. Examples of such are those items such as extension wires and cables, folding chairs, and other coiled metal objects that can resonate in the presence of the electromagnetic field of the EAS system. Another particular type of false alarm signal is a "ghost" alarm, which occurs when an EAS system sounds an alarm in response to the detection of a "background" signal, usually when no one is passing through the EAS system. Such as false alarms generated by tagged merchandise placed on a display area that is close enough to the EAS system to accidentally cause an alarm condition, or when tagged merchandise is temporarily introduced into the detection area but does not leave the retail space.

Another type of false alarm occurs when there is a failure to deactivate ("FTD") event that occurs when a tag is improperly deactivated or "injured". A tag is "wounded" when the tag has not been fully deactivated and is still at the threshold of the tag as a valid tag. For example, in current EAS systems, when an AM tag (also referred to herein as a "marker") is properly deactivated, the frequency of the marker detected by the system can be expected to be about 59.3 kHz. The frequency criteria of the AM detector reject marks with a detection frequency greater than 58.6 kHz. In some cases, a partially or improperly deactivated flag may have a frequency of less than 58.6kHz, in which case the system will inadvertently alarm (false alarm).

There is a need for a method and system that can be used to reduce or eliminate false alarms in EAS system detection zones, and in particular to reduce or eliminate false alarms when a tag is not properly deactivated.

Disclosure of Invention

The present invention advantageously provides a method, system and computer program product for managing false alarms in a security system. In one embodiment, the present invention provides a method for managing false alarms in a security system in which a detection zone is established. An alarm event is triggered based on detecting a tag in the detection zone using an initial alarm trigger sensitivity. The initial alarm trigger sensitivity is based on an initial setting of one or more detection criteria. The initial set of detection criteria is modified to adjust the alarm triggering sensitivity of the security system.

According to another aspect, the present invention provides a system for managing false alarms. The transmitter generates an applied interrogation field in the detection zone. The processor operates to trigger an alarm event in response to detecting a tag in the detection zone using an initial alarm trigger sensitivity, wherein the initial alarm trigger sensitivity is based on an initial setting of one or more detection criteria, and to modify the setting of the detection criteria to adjust the alarm trigger sensitivity of the security system.

According to another aspect, the present invention provides a computer program product comprising a computer useable medium having a computer readable program for a security system that when executed on a computer causes the computer to implement a method that includes establishing a detection zone. An alarm event is triggered based on detecting a tag in the detection zone using an initial alarm trigger sensitivity. The initial alarm trigger sensitivity is based on an initial setting of one or more detection criteria. The initial set of detection criteria is modified to adjust the alarm triggering sensitivity of the security system.

Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

A more complete appreciation of the invention and the attendant advantages and features thereof will be readily understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a block diagram of an electronic article surveillance system constructed in accordance with the principles of the present invention;

FIG. 2 is a block diagram of an exemplary data logger of the electronic article surveillance system of FIG. 1, constructed in accordance with the principles of the present invention;

FIG. 3 is a flow diagram of an exemplary false alarm reduction process in accordance with the principles of the present invention;

FIG. 4 is a diagram illustrating alarm activation frequency range adjustment according to the principles of the present invention;

FIG. 5 is a flow chart of an alarm activation frequency range adjustment process according to the principles of the present invention; and

fig. 6 is a flow chart of an energy-based alarm activation process according to the principles of the present invention.

Detailed Description

Referring now to the drawings in which like reference designators refer to like elements, there is shown in FIG. 1 a diagram of an exemplary system constructed in accordance with the principles of the present invention and designated generally as "100". An electronic article surveillance ("EAS") system 100 includes EAS detection units 102, 104, an EAS system controller 106, and a data logger 108, the EAS detection units 102, 104 being generally parallel and positioned at a distance from each other, the EAS system controller 106 being in communication with the EAS detection units 102, 104, the data logger 108 being in communication with the EAS system controller 106 via an EAS network 110. The EAS detection unit 102 may include a transmitter 112 and a transmitting antenna 114 for generating an electromagnetic field for use in conjunction with such a system to detect the presence of a tag (not shown) affixed to the article being protected. The remaining EAS detection unit 104 includes a receiver 116 and a receiving antenna 118, and the receiver 116 and receiving antenna 118 then operate to detect interference (resulting from the presence of active tags) in the electromagnetic field generated by the EAS detection unit 102, which can be used to sound an appropriate alarm. EAS system 100 may create detection zone 120 at a space such as a retail berth of a store, a store exit, etc.

In another embodiment, a single EAS detection unit 102 is provided that uses the transceiver 112 and the transceiver antenna 114 to establish the detection zone 120 by generating an electromagnetic field that is used to detect the presence of tags affixed to protected merchandise. In this embodiment, the transceiver 112 and the transceiver antenna 114 also operate to receive interference in the electromagnetic field generated by the EAS detection unit 102. For example, although FIG. 1 shows the EAS detection unit 102 as being equipped in a pedestal, the transceiver 112 and/or the transceiver antenna 114, or both, may be equipped on a door or at a store exit, for example. In this embodiment, the transceiver antenna 114 radiates a suitable electromagnetic or radio frequency field to create the detection zone 120.

The processing of the data and signals generated by the EAS detection units 102, 104 of the EAS system 100 is performed by an EAS system controller 106 associated with the EAS system 100, which EAS system controller 106 may be a separate unit or an integrated unit, such as housed in the transceivers/receivers 112, 116. In some embodiments, controller 106 performs one or more processes related to EAS applications. In this embodiment, the controller 106 is used to analyze the detection signals received by the receiver 116 to determine the presence of a tag in the detection zone 120 between the EAS detection units 102 and 104. Controller 106 executes instructions and processes data to carry out the operation of EAS system 100, and may be, for example, a central processing unit ("CPU"), an application specific integrated circuit ("ASIC"), or a field programmable gate array ("FPGA"). Controller 106 also controls the activation or initiation of a transmitter, such as transmitter 112, for all of the various configurations of EAS system 100.

EAS system 100 includes data logger 108, and data logger 108 is a unit that tracks the number and types of alarm events that occur in detection zone 120. The data logger 108 of fig. 2 includes one or more processors, such as processor 204. The processor 204 is connected to a communication infrastructure 202, such as a communication bus, crossbar, or wired/wireless network. Various software implementations are described in terms of this exemplary data logger 108. After reading this description, it will become apparent to a person having ordinary skill in the relevant art how to implement the invention using other computer systems and/or computer-based architectures.

The data logger 108 may include a user interface 208, which user interface 208 forwards graphics, text, and other data from the communication infrastructure 202 (or from a frame buffer not shown) for presentation on the display unit 210. The user interface 208 serves as an input device for human interaction. In some embodiments, the controller 106 may receive commands from an operator through the user interface 208 and other input devices such as a mouse or keyboard. For example, the data logger 108 may have a series of buttons on the periphery of the user interface 208 that allow the operator to enter a reason code for the alarm event.

The data logger 108 also includes a main memory 206, preferably Random Access Memory (RAM), and may also include a secondary memory 212. The secondary memory 212 may include, for example, a hard disk drive 214 and/or a removable storage drive 216, representing a floppy disk drive, a magnetic tape drive, an optical disk drive, a flash memory drive/memory, etc. The removable storage drive 216 reads from and/or writes to a removable storage unit 218 in a manner well known to those skilled in the art. Removable storage unit 218 represents, for example, a flash memory, a floppy disk, a magnetic tape, an optical disk, etc., where removable storage unit 218 is read by and written to by removable storage drive 216. It should be appreciated that the removable storage unit 218 includes a computer usable storage medium having stored therein computer software and/or data.

In alternative embodiments, the secondary memory 212 may include other similar means for allowing computer programs or other instructions to be loaded into the data logger 108. Such means may include, for example, a removable storage unit 222 and an interface 220. Examples of such may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as a flash memory, EPROM, or PROM) and associated socket, and other removable storage units 222 and interfaces 220, which interfaces 220 allow software and data to be transferred from the removable storage unit 222 to the data recorder 108.

The data logger 108 may also include a communication interface 224. The communication interface 224 allows software and data to be transferred between the data logger 108 and external devices, such as the EAS system controller 106. Examples of communications interface 224 may include a modem, a network interface (e.g., an ethernet card), a communications port, a PCMCIA slot and card, etc. Software and data transferred via communications interface 224 are in the form of signals which may be, for example, electronic, electromagnetic, optical or other signals capable of being received by communications interface 224. These signals are provided to communications interface 224 via a communications path or channel 226. Channel 226 carries signals and may be implemented using wire or cable, fiber optics, a phone line, a cellular phone link, an RF link, and/or other communications channels. In one embodiment, the data logger 108 communicates with the EAS system controller 106 via a network, such as an EAS network 110, including, but not limited to, various interface or data link standards such as recommended standard 232 ("RS-232"), recommended standard 485 ("RS-485"), universal serial bus ("USB"), ethernet transmission control protocol/internet protocol ("TCP/IP"), etc.

The terms "computer program medium," "computer usable medium," and "computer readable medium" are used to generally refer to media such as main memory 206 and secondary memory 212, removable storage drive 216, a hard disk installed in hard disk drive 214, and signals. These computer program products are means for providing software to the data logger 108. The computer readable medium allows the data recorder 108 to read data, instructions, messages or packets, and other computer readable information from the computer readable medium. The computer readable medium may include, for example, non-volatile memory, such as floppy disks, ROMs, flash memory, disk drive memory, CD-ROMs, and other permanent storage. For example, it is useful for transferring information, such as data and computer instructions, between computer systems. Further, the computer readable medium may comprise computer readable information in a transitory state medium such as a network link and/or a network interface, including a wireless network or a wired network that allow the data recorder 108 to read such computer readable information.

Computer programs (also called computer control logic) are stored in main memory 206 and/or secondary memory 212. Computer programs may also be received via communications interface 224. Such computer programs, when executed, enable the data logger 108 to implement the features of the present invention as discussed herein. In particular, the computer programs, when executed, may cause the processor 204 to implement features of the data logger 108.

Fig. 3 is a flow chart illustrating an exemplary method of false alarm management for EAS system 100 using data logger 108. The exemplary method is discussed with reference to EAS system 100, however, any other suitable system or portion of a system may use appropriate embodiments of the method to retrieve and process recorded EAS information to manage the sensitivity of EAS detection units 102, 104 in EAS detection zone 120. In general, a method for false alarm management describes a tag entering a detection zone 120 to generate an alarm event.

In step S302, it is determined whether an alarm event has occurred, such as when a tag attached to an object, such as an item of merchandise, enters the detection zone 120. If an alarm event is not detected, step S302 is repeated until an alarm event occurs. Once an alarm event occurs, the alarm event is investigated (step S304), for example, by an employee of a company equipped with the security system 100.

At step S306, the cause of the alarm event is determined and recorded at step S308. In one embodiment, an investigator, such as an employee of a company equipped with the security system 100, determines the cause of an alarm event, which may be, for example, a failure to deactivate ("FTD"), a false alarm, such as a merchandise false alarm, or a valid alarm, such as an alarm caused by unauthorized removal of an object at the company's premises. Each alarm event type may have a designated "reason code" that allows the investigator to enter into the data logger 108 or select from the data logger 108 to record the appropriate cause of the alarm event. Once the information for the alarm event is recorded into (or received by) the data logger 108, this information is sent back to the EAS system controller 106 in real time or with a delay for analysis and storage. For example, an alarm event is investigated and determined to be the result of a false alarm, and the reason code for the false alarm is entered into the data logger 108 by, for example, an investigator. At step S310, the reason code and information regarding the alarm event is transmitted to the EAS system controller 106 for processing and analysis.

If it is determined that there are too many false alarms (step S312), the system may be adjusted to change its alarm trigger sensitivity to a less sensitive level that allows for fewer false alarms. If there are not too many false alarms or deactivation failures, the process returns to step S302 to wait for the next alarm event.

According to one embodiment, the adjustments may be made using the data logger 108 described above. In another embodiment, discussed in detail below, the alarm trigger sensitivity may be reduced by reducing the allowed frequency of alarm events. In other words, the frequency threshold is automatically adjusted to prevent alarm events at the frequency of recorded false alarms. In yet another embodiment, also discussed below, the EAS system may automatically raise the signal-to-noise ratio ("SNR") threshold in an attempt to reduce the likelihood of another false alarm. System adjustment according to both embodiments is automatic and does not require the use of data logger 108. Thus, the EAS system controller 106 is arranged to operate without manual intervention and manual adjustment.

Tracking the estimated marker frequency for each alarm while keeping track is explained with reference to the frequency diagram of FIG. 4An example of an alarm rate, and an automatic adjustment process is shown in fig. 5. Current AM probes use frequency estimation algorithms to estimate the actual frequency of AM tags when detected by the system. The invention compares this frequency estimate with a predetermined initial effective frequency range (F)_min，F_max)402, and comparing. E.g. initial F_minAnd F_maxIs established (step S502). As shown in fig. 4, F in fig. 4_minIs 57.7kHz and the initial F_maxShown as 58.6 kHz. This assumes that the preferred receive frequency of the activated tag is 58.0 kHz. If the estimated tag frequency falls within the valid range (step S504), then the tag is considered valid and the system alarms (step S506). Otherwise, the tag is considered deactivated or out of frequency range. Methods for estimating the frequency of a received signal (e.g., a signal corresponding to an AM tag) are known and are outside the scope of the present invention.

As described above, the present invention tracks the estimated tag frequency for each alarm, for example via the controller 106, while keeping track of the alarm rate (step S508). The controller 106 also tracks the estimated average frequency (F) of tags causing an alarm_avg). If a large increase in the alarm rate above a predetermined alarm rate threshold is detected (step S510), the controller 106 will cause an estimated average frequency (F) of the alarming tags_avg) And FTD frequency threshold (F)_thr) And comparing (step 512). If the estimated average is above the FTD threshold, then the system will automatically reduce the maximum frequency (F) of the effective frequency_max) By the maximum value to be updated (updated F)_max)406 is set to less than the FTD threshold and a new updated range 404 is created (step S514).

For example, the natural frequency of a moving tag, also referred to as the characteristic frequency, is about 58 kHz. Thus, the detection platform is designed to operate at a frequency ranging from about 57.7kHz to 58.3 kHz. When the tag is properly deactivated, the characteristic frequency of the deactivated tag typically shifts to the 59-60kHz range, and is actually already outside the detection range, and thus cannot trigger an alarm event any more. However, a partially deactivated or "wounded" tag may shift its characteristic frequency to the 58.7-59kHz range, and thus the tag may be detected if the energy at the tag's new spectral characteristics, such as the tag's characteristic frequency, is large enough. Thus, by reducing the frequency range of active tags that are considered valid, damaged tags that would otherwise cause the system to generate false alarms are no longer considered, even improperly valid tags. It should be noted that this arrangement is most accurate in a high signal-to-noise ratio ("SNR") environment, as the accuracy of the frequency estimation algorithm decreases as the SNR decreases.

As described above, the present invention also provides an arrangement by which the failure to deactivate method is based on adjusting the detection criteria. According to this embodiment, the detection criterion is based on a comparison of energy levels at certain tag detection frequencies. The effect is that this embodiment is less sensitive to changes in SNR and even poor SNR environments, since the system is adjusted in a way that does not take noise into account, since the same noise level is usually present in the energy level of the monitored frequency. Energy-based alarm activation is described with reference to fig. 6.

According to this embodiment, the FTD ratio is established (step S602). This ratio, described in detail below, is used as a basis for determining whether the energy level of the first frequency is large enough to trigger an alarm.

In operation, the EAS system controller 106 calculates (step S604) and compares the received tag energies at the two different frequencies. For example, the first frequency (f1) is the effective received tag frequency, e.g., 58kHz, while the second frequency (f2) is the expected deactivated tag frequency, e.g., 59.3 kHz. However, in a low SNR environment, even if there is sufficient energy at 58kHz to trigger an alarm, if there is more marker energy at 59.3kHz compared to 58kHz, then the system considers the marker to be deactivated and not to alarm.

According to this embodiment, the FTD ratio is calculated (step S606) to compare the received tag energy levels at the two frequencies. For example, the FTD ratio is f1 energy/f 2 energy. Using the exemplary values provided above, the FTD ratio is 58kHz energy/59.3 kHz energy.

This ratio is then compared to a predetermined FTD ratio threshold. The FTD rate threshold is the minimum amount of energy that must be present at f1 above the energy level at f2 that triggers an alarm. If the FTD ratio is above the FTD ratio threshold (step S608), it may be determined that the marker energy at f1(58kHz) is higher than the energy at f2(59.3kHz), and the controller 106 activates an alarm (step 610).

For example, to reduce FTD alarms due to tag frequencies near 58.6kHz, the controller 106 may initially track the average energy at f2(59.3kHz) of the tag that triggered the alarm, while also tracking the alarm rate (step S612). If a large increase in the alarm rate is detected above the threshold alarm rate (step S614), the controller 106 evaluates the average of the energy levels at f2(59.3kHz) and determines if the energy level at f2(59.3kHz) increases during the alarm (step S616). If the energy level increases, the FTD threshold is increased by a predetermined amount to reduce false alarms (step S618). The result is that the sensitivity of the system is reduced to reduce instances of false alarms.

According to the present invention, adjustments to the EAS system detection sensitivity by comparing and then adjusting the energy level threshold and/or by reducing the allowable frequency of alarm events are included as detection criteria. The use of such detection criteria is advantageously applicable to both deactivation failure and false alarm problems. It is noted that while the functionality for automatically adjusting the alarm trigger threshold frequency and energy level ratio is described with reference to the EAS system controller 106, it should be appreciated that such functionality need not be implemented solely by the controller 106. It should be appreciated that a separate computing device may be in electronic communication with the controller 106, and that this separate computing device may be programmed to implement the automatic adjustment of alarm triggering functions described herein.

The present invention advantageously provides and defines a comprehensive system and method for utilizing real-time data logging techniques to reduce false alarms and deactivation failures in an EAS system.

The present invention can be realized in hardware, software, or a combination of hardware and software. An implementation of the method and system of the present invention can be realized in a centralized fashion in one computing system or in a distributed fashion where different elements are spread across several interconnected computing systems. Any kind of computing system, or other apparatus adapted for carrying out the methods described herein, is suited to perform the functions described herein.

A typical combination of hardware and software could be a special purpose or general-purpose computer system with one or more processing elements and a computer program stored on a storage medium that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which-when loaded in a computer system-is able to carry out these methods. Storage medium refers to any volatile or non-volatile storage device.

Computer program or application in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in different material forms. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. Significantly, this invention can be embodied in other specific forms without departing from the spirit or essential attributes thereof, and accordingly, reference should be had to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Many modifications and variations are possible in light of the above teaching without departing from the spirit and essential attributes of the invention, and accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims (15)

1. A method for managing false alarms in a security system, the method comprising:

establishing a detection area;

triggering an alarm event, the alarm event based on detecting a tag in the detection zone using an initial alarm trigger sensitivity, the initial alarm trigger sensitivity based on an initial setting of one or more detection criteria; and

modifying the setting of the detection criteria includes adjusting an energy level ratio threshold at a preselected tag detection frequency to adjust the alarm trigger sensitivity of the security system, wherein the energy level ratio threshold is a minimum amount of energy that must be present at a first frequency that is higher than an energy level at a second frequency to trigger an alarm.

2. The method of claim 1, further comprising determining a cause of the alarm event.

3. The method of claim 1, further comprising receiving a reason code, the reason code including information related to the alarm event.

4. The method of claim 3, wherein said modifying the setting of the detection criteria comprises:

processing reason code information to determine one or more of said detection criteria to be modified; and

the modified one or more detection criteria are stored.

5. The method of claim 1, wherein the alarm event is triggered if a ratio of a detected first energy level at a first frequency to a detected second energy level at a second frequency is greater than a predetermined energy level ratio threshold.

6. The method of claim 5, wherein the alarm trigger sensitivity is adjusted to decrease the alarm trigger sensitivity of the security system, decreasing the alarm trigger sensitivity of the security system comprising increasing the predetermined energy level ratio threshold.

7. The method of claim 1, wherein the setting of the detection criteria comprises a frequency threshold.

8. The method of claim 7, wherein the range of valid alarm trigger frequencies is reduced when the average, detected frequency of tags causing an alarm is greater than the frequency threshold.

9. A system for managing false alarms in a security system, the system comprising:

a transmitter that generates an applied interrogation field in a detection zone;

a processor operative to:

triggering an alarm event in response to detecting a tag in the detection zone using an initial alarm trigger sensitivity, the initial alarm trigger sensitivity based on an initial setting of one or more detection criteria; and

modifying the setting of the detection criteria includes adjusting an energy level ratio threshold at a preselected tag detection frequency to adjust the alarm trigger sensitivity of the security system, wherein the energy level ratio threshold is a minimum amount of energy that must be present at a first frequency that is higher than an energy level at a second frequency to trigger an alarm.

10. The system of claim 9, wherein the processor further operates to determine a cause of the alarm event.

11. The system of claim 9, wherein the processor is further operative to:

processing reason code information to determine one or more of said detection criteria to be modified; and

the modified one or more detection criteria are stored.

12. The system of claim 11, wherein the processor operates to trigger the alarm event if a ratio of a detected first energy level at a first frequency to a detected second energy level at a second frequency is greater than a predetermined energy level ratio threshold.

13. The system of claim 12, wherein the processor is further operative to adjust the alarm trigger sensitivity by decreasing the alarm trigger sensitivity of the security system, the decreasing the alarm trigger sensitivity of the security system comprising increasing the predetermined energy level ratio threshold.

14. The system of claim 9, wherein the setting of the detection criteria comprises a frequency threshold.

15. The system of claim 14, wherein the processor is further operative to reduce a frequency range in which activated tags are detected when an average detected frequency of tags causing an alarm trigger is greater than the frequency threshold.