HK1169879B - System and method for reducing cart alarms and increasing sensitivity in an eas system with metal shielding detection - Google Patents

Description

System and method for reducing cart alarms and increasing sensitivity of EAS systems with metal shield detection

Technical Field

The present invention relates generally to electronic article surveillance ("EAS") systems and more particularly to a method and EAS system that detects metal and magnetic materials and reduces false alarms caused by the presence of metal carts in an EAS interrogation zone.

Background

Electronic article surveillance ("EAS") systems are commonly used in retail stores and other locations to prevent unauthorized removal of goods from protected areas. Typically, a detection system is deployed at a protected area exit, which includes one or more transmitters and antennas ("pedestals") that can generate an electromagnetic field (referred to as an "interrogation zone") across the exit. An item to be protected is tagged with an EAS marker which, when activated, generates an electromagnetic response signal when passing through this interrogation zone. An antenna and receiver in the same or another "pedestal" detects this response signal and generates an alarm.

Due to the nature of this process, other magnetic substances or metals (e.g., metal shopping carts) in proximity to the EAS marker or transmitter may interfere with the optimal performance of the EAS system. In addition, some miscreants use EAS marker shielding (e.g., foil) in order to steal merchandise without being detected by any EAS system. The metal may shield the tagged items from detection by the EAS detection system.

Current EAS systems implementing metal shielded detection mechanisms can sometimes be fooled by various cart configurations and overpowered by a large number of metal responses. Some systems attempt to overcome this problem by reducing the system gain, which limits sensitivity and reduces the detection capability of small items, such as metal shields that the system is attempting to detect.

Other conventional systems may include a "shopping cart disable" feature in an EAS system/metal detection configuration. By monitoring the excess metal response signal, a threshold value indicating a forbidden condition may be implemented so that the system will not erroneously generate an alarm. However, even with such a solution implemented, some store goods will continue to fool the system and cause false alarms or missed detections. For example, because these shields generate readings that exceed a threshold, the detection of large metal shields positioned close to the pedestal is reduced.

Accordingly, there is a need for a system and method for independently detecting the presence of a cart or stroller within an EAS interrogation zone that allows for increased sensitivity of EAS systems having metal shielding detection capabilities.

Disclosure of Invention

The present invention advantageously provides a method and system for detecting electronic article surveillance ("EAS") marker shielding by independently detecting the presence of a cart or other wheeled device within an EAS interrogation zone. In general, the present invention is able to distinguish a wheeled device from a human being between pedestals by inspecting a cut-off pattern with a sensor array positioned on the pedestals just above the floor.

In accordance with one aspect of the invention, a system for detecting EAS marker shielding includes an EAS subsystem, a metal detector, a cart detection subsystem, and a processor. The EAS subsystem is operable to detect an EAS marker in an interrogation zone. The metal detector is operable to detect a metal object in the interrogation zone. The cart detection subsystem includes a sensor array. The cart detection subsystem is operable to distinguish a wheeled device passing through the interrogation zone from a human based on the sensor array. The processor is electrically coupled to the EAS subsystem, the metal detector, and the cart detection system. The processor is programmed to receive information output from the cart detection system and information output from the metal detector to determine whether to generate an alarm signal based on the presence of EAS marker shielding.

In accordance with another aspect of the present invention, a method for detecting EAS marker shielding is provided. A metallic object is detected within the interrogation zone. Distinguishing wheeled devices passing through the interrogation zone from humans. In response to determining that the wheeled device has not passed through the interrogation zone, an alarm signal is generated informing of the presence of EAS marker shielding.

In accordance with yet another aspect of the invention, an electronic EAS system controller for use with a metal detector includes an EAS subsystem, a communication interface, a cart detection subsystem, and a processor. The EAS subsystem is operable to detect an EAS marker in an interrogation zone. The communication interface is operable to receive input from the metal detector. The cart detection subsystem includes a sensor array. The cart detection subsystem is operable to distinguish a wheeled device passing through the interrogation zone from a human based on the sensor array. The processor is electrically coupled to the EAS subsystem, the communication interface, and the cart detection subsystem. The processor is programmed to receive information output from the cart detection system and information output from the metal detector to determine whether to generate an alarm signal based on the presence of EAS marker shielding.

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 exemplary electronic article surveillance ("EAS") detection system having metal detection, cart detection, and people counting capabilities constructed in accordance with the principles of the present invention;

FIG. 2 is a side perspective view of a cart passing through the exemplary EAS system of FIG. 1 constructed in accordance with the principles of the present invention;

FIG. 3 is a front perspective view of a cart passing through the exemplary EAS system of FIG. 1 constructed in accordance with the principles of the present invention;

FIG. 4 is a block diagram of an exemplary EAS system controller constructed in accordance with the principles of the present invention;

FIG. 5 is a flow chart of an exemplary cart detection process according to the principles of the present invention;

FIG. 6 is a block diagram of an exemplary configuration of an infrared detection sensor constructed in accordance with the principles of the present invention;

fig. 7 is a flow chart illustrating an exemplary firing sequence of the infrared detection sensor configuration of fig. 6 in accordance with the principles of the present invention.

FIG. 8 is a block diagram of an alternative configuration of an infrared detection sensor constructed in accordance with the principles of the present invention;

FIG. 9 is a flow chart illustrating an exemplary firing sequence of the infrared detection sensor configuration of FIG. 8, according to the principles of the present disclosure;

FIG. 10 is a side perspective view of a cart clearly passing through the sensor beam of the exemplary EAS system of FIG. 1, in accordance with the principles of the present invention;

FIG. 11 is a side perspective view of a cart obscuring at least one sensor beam of the exemplary EAS system of FIG. 1, in accordance with the principles of the present invention; and

fig. 12 is a flow chart of an exemplary blocked sensor detection process according to the principles of the present invention.

Detailed Description

Before describing in detail exemplary embodiments that are in accordance with the present invention, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to implementing a system for independently detecting the presence of a cart or stroller within an EAS interrogation zone, thereby allowing for increased sensitivity of an EAS system having EAS marker shielding detection capabilities. Accordingly, the system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

As used herein, relational terms (e.g., "first" and "second," "top" and "bottom," etc.) may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements.

One embodiment of the present invention advantageously provides a method and system for detecting a cart or stroller in an interrogation zone of an EAS system and improving the sensitivity of the EAS system to detect EAS marker shielding. The EAS system combines conventional EAS detection capabilities with a set of infrared sensor arrays positioned near the floor on the base of the EAS pedestal to detect the movement of the wheels past the interrogation zone.

Referring now to the drawings, in which like reference designators refer to like elements, there is shown in FIG. 1 a configuration of an exemplary EAS detection system 10 constructed in accordance with the principles of the present invention and located, for example, at an entrance to a facility. The EAS detection system 10 includes a pair of pedestals 12a, 12b (collectively pedestals 12) on opposite sides of an entrance 14. One or more antennas of the EAS detection system 10 may be included in pedestals 12a and 12b located a known distance apart. The antenna positioned in the pedestal 12 is electrically coupled to a control system 16 that controls the operation of the EAS detection system 10. The system controller 16 is electrically connected to a metal detector 18, a people counting system 20 and an infrared sensor array 22 for more accurately detecting the presence of foil bags. The infrared sensor array 22 is composed of a pair of infrared sensor panels 22a, 22b (collectively referred to as "infrared sensor panels 22"). It is also contemplated that other types of sensor arrays may be used, such as pressure sensitive pads arranged to provide data indicating where pressure has been applied, and the like.

The metal detector 18 may be a separate unit communicatively connected to the system controller 16, or may be incorporated into the system controller 16. Exemplary Metal detector 18 is disclosed in U.S. patent application No. 12/492,309 entitled "Electronic apparatus surface System with Metal detection capability and Method for", filed on 26/6/2009, the entire teachings of which are incorporated herein by reference.

The people counting system 20 may be a separate device (e.g., an indirect people counter) or may be physically located on one or more pedestals 12 and/or incorporated into the system controller 16. For example, the people counting system may include one or more infrared sensors mounted approximately 8 feet to 14 feet (2.5 m to 4.3 m) above the retailer's entrance/exit. Incorporating a people counting sensor into the EAS detection pedestal 12 helps ensure a simple and efficient method of communicating basic operational information. In operation, the people counter detects the movement of people into, through, or out of a predetermined area. The information is collected and processed, for example, by the people counting system 20 using a programmed microprocessor. The people counting data may then be transmitted using conventional network connection means and/or through the store's internal network or through a wide area network (e.g., the internet) to other portions of the EAS detection system 10 where the data may be categorized, reported and studied.

Referring now to fig. 2 and 3, perspective views of a cart 24 passing through the exemplary EAS system 10 are provided. As can be seen in fig. 2, the infrared sensor array 22 is positioned at the base of the pedestal 12 at a height of about 1/4 inches (6.4mm) to 2 inches (51mm) from the floor. The length of the infrared sensor array 22 should be at least 6 inches to 12 inches (152 mm-305 mm) long to allow for differentiation of the cart wheels from the human feet. The array of infrared sensors 22 is arranged so that the sensors produce a plurality of parallel beams 26 between the pedestals 12, as shown in fig. 3. As the light beam approaches the floor, the light beam 26 is cut off by the wheels of the cart 24, stroller or other wheeled object passing between the pedestals 12. The beam 26 is also switched when the pedestrian is between the pedestals; however, the cut-off pattern of the pedestrian passing the light beam 26 is different than the cut-off pattern of the cart 24 rolling through the light beam 26. For example, the cart 24 will sequentially switch off the beams 26 and will pass all the way through each beam 26 since the wheels of the cart 24 never exit the floor, but a pedestrian may switch off several beams 26 at the same time and not necessarily each beam 26 in the array 22. By identifying differences in these patterns, one embodiment of the present invention is able to distinguish the cart 24 or stroller from other metal objects and use this information to increase the sensitivity and accuracy of its foil-lined bag detection. The operation of the infrared sensor array 22 of the combined system controller 16 is discussed in more detail below.

Referring now to fig. 4, the exemplary EAS system controller 16 may include a controller 28 (e.g., a processor or microprocessor), a power supply 30, a transceiver 32, a memory 34 (which may include non-volatile memory, or a combination thereof), a communication interface 36, and an alarm 38. The controller 28 controls radio communications, stores data to the memory 34, communicates stored data to other devices, and activates the alarm 38. A power supply 30 (e.g., a battery or AC power supply) supplies power to the EAS control system 16. The alarm 38 may include software and hardware for providing a visual and/or audible alert in response to the detection of an EAS marker and/or metal within the interrogation zone of the EAS system 10.

The transceiver 32 may include: a transmitter 40 electrically coupled to one or more transmit antennas 42; and a receiver 44 electrically coupled to one or more receive antennas 46. Alternatively, a single antenna or a pair of antennas may be used as both the transmit antenna 42 and the receive antenna 46. The transmitter 40 transmits a radio frequency signal using a transmit antenna 42 to "excite" an EAS marker within the interrogation zone of the EAS system 10. The receiver 44 detects the response signal of the EAS marker using the receive antenna 46. It is also contemplated that the exemplary system 10 may include the transmitting antenna 42 and the receiver 44 in one pedestal (e.g., pedestal 12 a) and the reflective substance in another pedestal (e.g., pedestal 12 b).

The memory 34 may include: a metal detection module 48 for detecting the presence of metal within the interrogation zone; and a cart detection module 50 for determining whether the detected metal is a cart, stroller, or other wheeled object, such as a wheelchair, a hand truck, or the like. The operation of the metal detection module 48 and the cart detection module 50 is described in more detail below. The metal detection module 48 in combination with the cart detection module 50 may determine whether to trigger the alarm 38 by analyzing output information received from the metal detector 18, the people counting system 20, and the infrared sensor array 22 via the communication interface 36. For example, if the cart detection module 50 has detected that a person passed the interrogation zone and the metal detector 18 has just detected a metal source that meets the metal shielding characteristics, the metal detection module 48 may trigger the alarm 38 by sending an alarm signal via the controller 28. An alarm 38 alerts store security or other authorized personnel who may monitor or approach the individual as desired.

The controller 28 may also be electrically coupled to a real time clock ("RTC") 52 that monitors the passage of time. The RTC 52 may act as a timer to determine whether an event actuation, such as metal detection or people counting, has occurred within a predetermined time frame. The RTC 52 may also be used to generate a time stamp so that the time of alarm or event detection can be recorded.

Referring now to fig. 5, a flowchart is provided that describes exemplary steps performed by the EAS system to determine whether an object passing through the pedestal 12 is a cart 24 or other wheeled device. The system controller 16 sequentially enables the infrared sensor arrays 22 by activating the light beams, depending on the configuration of the infrared sensor arrays 22 (step S102).

The infrared sensor array 22 may be configured in a variety of ways. For example, as shown in fig. 6, the infrared sensor array 22 may have: a sensor panel 22a including only emitting assemblies 54a-54j (collectively, "emitting assemblies 54"); and a second sensor panel 22b that includes only receiving assemblies 56a-56j (collectively, "receiving assemblies 56"). It should be noted that although fig. 6 shows 10 pairs of infrared sensors, the number of sensor pairs is shown for illustrative purposes only, and any number of sensor pairs that can reliably produce an identifiable cutoff pattern may be selected for implementation. For example, the present invention has been found to perform statistically using 5 pairs of sensors. Also, while any sensor spacing may be used (as long as the spacing allows for determination of a wheeled cart as described herein for a human), one embodiment of the present invention implements sensors that are spaced about 2.75 inches to 3.00 inches (69.9 mm to 76.0 mm) apart.

Although sensors having focusing elements are preferred, the invention can be practiced using non-focusing elements. Also, while an automatic gain control ("AGC") circuit may be used as part of the sensor circuit, the invention may be implemented using a sensor circuit that does not include an AGC circuit. It has been found that the latter embodiment allows operation in a faster cycle time, as compared to the former embodiment, thereby providing improved accuracy. In the configuration shown in fig. 6, all of the emitting components 54 and receiving components are active simultaneously, so the system controller 16 activates only the entire infrared sensor array 22 in the beam sequence that initiates step S102.

Fig. 7 shows an alternative configuration of the infrared sensor array 22. Similar to the arrangement shown in fig. 6, all of the transmit components 54 are positioned on the same sensor panel 22a, and the receive components 56 are positioned on the opposite sensor panel 22 b. However, in this configuration, the controller 28 quickly sequences the beams, with only a single pair of sensors active at any one time. One embodiment of the present invention uses a sequencing rate of 200 Hz. For example, in fig. 7, during the first ignition cycle (ignition cycle a), the transmitting sensor 54a transmits, and only the receiving sensor 56a functions to receive. During the second firing cycle (firing cycle B), the transmitting sensor 54B transmits and only the receiving sensor 56B functions to receive. Each pair of infrared sensors is then activated until all sensors have been fired and the sequence starts again with the first pair of sensors. Thus, the receiving sensor 56 is guaranteed to receive only signals originating from the corresponding emitting sensor 54 of the sensor pair, thereby eliminating false triggering of adjacent beams and improving overall sensitivity. In addition, this sequencing mechanism allows the use of less expensive infrared sensors (as compared to the sensor in fig. 6) because each beam need not have a very narrow, focused beam, which is a feature that increases the part cost of the infrared sensor pair. Using a less focused beam allows for easier alignment of the transmit sensor 54 with the receive sensor 56.

Fig. 8 shows an alternative configuration of the infrared sensor array 22. In this configuration, the transmitting assemblies 54 and receiving assemblies 56 alternate between the infrared sensor panels 22a and 22b to improve flexibility between adjacent infrared beams 26.

Fig. 9 illustrates another alternative configuration of infrared sensor array 22, in which the physical configuration of fig. 8 (i.e., transmission assembly 54 alternating with reception assembly 56) is combined with the firing sequence shown in fig. 7 to provide even greater flexibility between adjacent light beams 26 and also minimize false triggers.

Referring now to fig. 5, the beam sequence runs in a continuous loop as long as no beam is cut off (step S102). When the system controller 16 detects that the light beam has been cut off (step S104), the cart detection module 50 monitors the infrared sensor array 22 to determine whether the current beam cut-off pattern matches the expected pattern of the wheel (step S106). For example, the desired pattern for the wheel may be one in which each beam is cut off in sequence for a given number of beams (up to and including all beams) and only the given number of beams are cut off at any one time. If the pattern does not match the expected pattern of the wheels, the cart detection module 50 compares the cut-off pattern to the expected pattern of the pedestrian (step S108). The desired pattern of the pedestrian may be that up to a predetermined number of beams are switched off simultaneously and/or that not all beams of the array are triggered. If the pattern matches a pedestrian, the people counter 20 is incremented (step S110) and the step ends. If the pattern does not match the expected pattern of a pedestrian (step S108), the cart detection module 50 returns to decision block S104 to detect whether any other light beams have been switched off, thereby changing the current switching off pattern.

Returning to decision block S106, if the current cutoff pattern matches the expected pattern for the wheel, the system controller 16 determines whether metal detection module 48 has detected the presence of metal within the interrogation zone (step S112). The metal detection module 48 may simply indicate the presence of metal within the interrogation zone or may return a response reading proportional to the amount of metal detected, in which case the system controller 16 determines whether the response reading is greater than a predetermined threshold indicative of a response generated by a large metal object (e.g., a cart). If no metal is detected, the process ends. However, if metal is present (step S112), then the system controller 16 prevents the metal detection module 48 from generating an alarm indicating the presence of metal shielding (step S114). Similarly, if the metal detection module 48 detects metal in the interrogation zone and the cart detection module 50 determines that a cart is not present, the system controller 16 may instruct the metal detection module 48 to generate an alarm indicating the presence of metal shielding. The process shown in fig. 5 may be repeated continuously or at predetermined intervals.

Referring now to fig. 10, the method of fig. 5 can accurately detect a cart 24 or other wheeled device as long as the cart is actually moving past the interrogation zone and the infrared beam 26 is cut off. However, when the cart 24 is parked in the middle of the pedestals 12 (as shown in fig. 11), or when other items remain stationary between the pedestals 12, one or more pairs of sensors are blocked and do not function properly.

Referring now to fig. 12, a flowchart is provided that describes exemplary steps performed by the EAS system 10 to detect one or more pairs of blocked sensors. The system controller 16 activates the infrared sensor array 22 by activating the light beam sequence in the cart detection process as detailed above in fig. 5 (step S116). If the single beam is switched off (step S118), then real time clock 52 starts a countdown timer (step S120).

The countdown timer may set a predetermined amount of time, such as 30 seconds, 1 minute, etc. Once the beam is switched off, a countdown timer is started. As long as the countdown timer has not reached the terminal count (step S122) (i.e., t = 0), the cart detection module 50 continues to monitor the blocked sensors to determine whether the sensors become unblocked (step S124). If the sensor becomes unblocked, the system controller 16 sets the status of the sensor to active (step S126) and returns to decision block S118 to continue monitoring for blocked sensors. However, if the countdown timer reaches the terminal count and the blocked sensor has not become unblocked (step S124), the cart detection module 50 sets the status of the blocked sensor to inactive and does not use the blocked sensor during cart detection (step S128). If a previously blocked sensor becomes unblocked by repeating the process of blocking the sensor, the blocked sensor may return to the active state. It should be noted that the start value of the countdown timer may be set large enough to avoid generating a false lockout trigger.

In the event that the blocked sensor process determines that multiple light beams are blocked (such as may occur if a cart remains in the interrogation zone, personnel wander too long in the interrogation zone, or even some other object blocks multiple sensors), the prospective system may alert the store manager or some other designated personnel.

The present invention can be realized in hardware, software, or a combination of hardware and software. 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 specialized computer system having one or more processing elements and a computer program stored on a storage medium that, when 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 computing system-is able to carry out these methods. Storage media refers to any volatile or non-volatile storage device.

Computer program or application in the context of the present invention 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) regeneration in different substance forms.

Moreover, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. It will be evident that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims (20)

1. A system for detecting Electronic Article Surveillance (EAS) marker shielding, the system comprising:

an EAS subsystem configured to detect an EAS marker in an interrogation zone;

a metal detector configured to detect a metal object in the interrogation zone;

a cart detection subsystem comprising a sensor array configured to form a plurality of severable light beams, the cart detection subsystem configured to:

detecting a wheeled device passing through the interrogation zone by matching the pattern of the broken beam with an expected pattern of the wheeled device; and

detecting a human passing through the interrogation zone by matching the pattern of the cut-off beam with an expected pattern of a pedestrian; and

a processor electrically coupled to the EAS subsystem, the metal detector, and the cart detection subsystem, the processor configured to:

generating an alarm signal if the metallic object and human being are detected and the wheeled device is not detected, the alarm indicating the presence of EAS marker shielding.

2. The system of claim 1, wherein the interrogation zone is positioned between a pair of EAS pedestals, each EAS pedestal having a base end positioned to rest on a floor, the sensor array comprising:

a plurality of pairs of infrared sensors, each pair of infrared sensors including a transmitting assembly positioned on one EAS pedestal of the pair of EAS pedestals and a receiving assembly positioned on the other EAS pedestal of the pair of EAS pedestals, such that when activated, each infrared sensor pair forms one of the plurality of chopped light beams between the pedestals, each chopped light beam being an infrared beam.

3. The system of claim 2, wherein each infrared beam is positioned sufficiently above an end of the pedestal base such that the infrared beam is cut off by wheels of the wheeled device rolling between the pedestals.

4. The system of claim 2, wherein each infrared beam is positioned substantially parallel to the floor and substantially parallel to all other infrared beams.

5. The system of claim 4, wherein each infrared beam is positioned at a height of substantially 1/4 inches (6.4mm) to substantially 2 inches (51mm) above a base end of the pedestal.

6. The system of claim 2, wherein the plurality of pairs of infrared sensors are activated simultaneously.

7. The system of claim 2, wherein each of the plurality of pairs of infrared sensors is activated individually for a predetermined duration and in sequence.

8. The system of claim 2, wherein the processor is further configured to determine whether other light beams have been cut if a determination is made that the pattern of the cut-off light beams does not match the expected pattern of the wheeled device and the expected pattern of the pedestrian.

9. The system of claim 1, wherein the desired pattern of the wheeled device includes activating each pair of infrared sensors in sequence.

10. The system of claim 1, wherein the expected pattern of pedestrians comprises triggering more than one pair of infrared sensors simultaneously.

11. The system of claim 1, wherein the processor generates the alert signal in response to:

the metal detector detects a metal object in the interrogation zone; and

the cart detection subsystem determines that a wheeled device has not passed through the interrogation zone.

12. The system of claim 1, wherein the processor is further configured to determine that at least one pair of infrared sensors is blocked, the cart detection subsystem further configured to deactivate the at least one blocked pair of infrared sensors based at least in part on determining that the at least one pair of infrared sensors is blocked.

13. A method for detecting Electronic Article Surveillance (EAS) marker shielding, the method comprising:

a plurality of severable beams formed within an interrogation zone;

detecting a metallic object within the interrogation zone;

determining that a wheeled device is passing through the interrogation zone if the pattern of the broken beam matches an expected pattern of the wheeled device;

determining that a human is passing the interrogation zone if the pattern of the broken beam matches an expected pattern of a pedestrian; and

generating an alert signal notifying the presence of EAS marker shielding based at least in part on the detecting and determining that a human being is passing the interrogation zone and the wheeled device is not passing the interrogation zone.

14. The method of claim 13, wherein the interrogation zone is formed between a pair of EAS pedestals, each EAS pedestal having a base end positionable on a floor, wherein a sensor array forms the plurality of severable beams, the sensor array comprising:

a plurality of pairs of infrared sensors, each pair of infrared sensors including a transmitting assembly positioned on one EAS pedestal of the pair of EAS pedestals and a receiving assembly positioned on the other EAS pedestal of the pair of EAS pedestals, such that when activated, each pair of infrared sensors forms one of the plurality of chopped light beams between the pedestals, each chopped light beam being an infrared beam.

15. The method of claim 14, wherein each infrared beam is positioned sufficiently above the pedestal base such that each infrared beam is cut off by a wheel of a wheeled device rolling between the pedestals.

16. The method of claim 14, further comprising: if a determination is made that the pattern of the broken light beam does not match the expected pattern of the wheeled device and the expected pattern of the pedestrian, a determination is made as to whether other light beams have been broken.

17. The method of claim 14, further comprising:

determining that at least one pair of infrared sensors is blocked; and

disabling the at least one pair of blocked infrared sensors based at least in part on determining that the at least one pair of infrared sensors are blocked.

18. An Electronic Article Surveillance (EAS) system controller for use with a metal detector configured to detect a metal object in an interrogation zone, the EAS system controller comprising:

an EAS subsystem configured to detect an EAS marker in an interrogation zone;

a communication interface configured to receive input from the metal detector, the metal detector configured to detect a metallic object in the interrogation zone;

a cart detection subsystem comprising a sensor array configured to form a plurality of severable light beams, the cart detection subsystem configured to:

determining that a wheeled device is passing through the interrogation zone by matching the pattern of the broken beam with an expected pattern of the wheeled device; and

determining that a human being is passing the interrogation zone by matching the pattern of the broken beam with an expected pattern of a pedestrian; and

a processor electrically coupled to the EAS subsystem, the communication interface, and the cart detection subsystem, the processor configured to generate an alarm signal if it is determined that a human being is passing through the interrogation zone and a metallic object is detected within the interrogation zone, the alarm indicating the presence of EAS marker shielding; and

the alarm signal is disabled if it is determined that a wheeled device is passing through the interrogation zone and a metallic object is detected within the interrogation zone.

19. The EAS system controller of claim 18, wherein the interrogation zone is formed between a pair of EAS pedestals, each EAS pedestal being positioned to rest on a floor, the sensor array comprising a plurality of pairs of infrared sensors, each pair of infrared sensors comprising a transmit assembly and a receive assembly, the transmit assembly being positioned on one EAS pedestal of the pair of EAS pedestals and the receive assembly being positioned on the other EAS pedestal of the pair of EAS pedestals, such that when activated, each pair of infrared sensors forms one of the plurality of severable light beams between the pedestals, each severable light beam being an infrared beam.

20. The EAS system controller of claim 19, wherein the processor is further configured to determine that at least one pair of infrared sensors is blocked, the cart detection subsystem further configured to disable the at least one blocked pair of infrared sensors based at least in part on determining that the at least one pair of infrared sensors is blocked.