Systems and methods for imaging using a sensor array for magneto-active security elements

Abstract

A system (1000) includes at least one processor (1010), a sensor array (1002) configured to generate a magnetic field influenceable by magnetically active security elements of magneto-active articles, and a frequency change detection subsystem (1008). The frequency change detection subsystem is configured to, using a sensor signal output, determine a time interval between an end of a start pulse and a next rising edge of the sensor signal output. The frequency change detection subsystem is also configured to measure a change in a sensor oscillation frequency across the time interval. The at least one processor is configured to detect a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

Description

SYSTEMS AND METHODS FOR IMAGING USING A SENSOR ARRAY FOR MAGNETO-ACTIVE SECURITY EEEMENTSTECHNICAE FIELD

[0001] This disclosure relates generally to automated currency systems. More specifically, this disclosure relates to systems and methods for imaging using a sensor array for magneto-active security elements.BACKGROUND

[0002] Articles such as banknotes, securities, documents, and other items can have magneto-active security elements embedded therein, or attached to a surface thereon, to be used for detection or authentication. While attempts have been made to provide systems for detecting and authenticating the magneto-active security elements of such articles, use of these systems has been prohibitive due to deficient detection speeds and costly implementation.SUMMARY

[0003] This disclosure relates to systems and methods for imaging using a sensor array for magnetoactive security elements.

[0004] In one aspect thereof, a system includes at least one processor, a sensor array configured to generate a magnetic field influenceable by magnetically active security elements of magneto-active articles, and a frequency change detection subsystem. The frequency change detection subsystem is configured to, using a sensor signal output, determine a time interval between an end of a start pulse and a next rising edge of the sensor signal output. The frequency change detection subsystem is also configured to measure a change in a sensor oscillation frequency across the time interval. The at least one processor is configured to detect a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

[0005] In another aspect thereof, a method includes determining, using a frequency change detection subsystem, and from a sensor signal output created using a sensor array that generates a magnetic field influenceable by magnetically active security elements of magneto-active articles, a time interval between an end of a start pulse and a next rising edge of the sensor signal output. The method also includes measuring a change in a sensor oscillation frequency across the time interval. The method also includes detecting a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

[0006] Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and / or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with,have, have a property of, have a relationship to or with, or the like. The term “controller” means any device, system or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0007] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms “application” and “program” refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0008] As used here, terms and phrases such as “have,” “may have,” “include,” or “may include” a feature (like a number, function, operation, or component such as a part) indicate the existence of the feature and do not exclude the existence of other features. Also, as used here, the phrases “A or B,” “at least one of A and / or B,” or “one or more of A and / or B” may include all possible combinations of A and B. For example, “A or B,” “at least one of A and B,” and “at least one of A or B” may indicate all of (1) including at least one A, (2) including at least one B, or (3) including at least one A and at least one B. Further, as used here, the terms “first” and “second” may modify various components regardless of importance and do not limit the components. These terms are only used to distinguish one component from another. For example, a first user device and a second user device may indicate different user devices from each other, regardless of the order or importance of the devices. A first component may be denoted a second component and vice versa without departing from the scope of this disclosure.

[0009] It will be understood that, when an element (such as a first element) is referred to as being (operatively or communicatively) “coupled with / to” or “connected with / to” another element (such as a second element), it can be coupled or connected with / to the other element directly or via a third element. In contrast, it will be understood that, when an element (such as a first element) is referred to as being “directly coupled with / to” or “directly connected with / to” another element (such as a second element), no other element (such as a third element) intervenes between the element and the other element.

[0010] As used here, the phrase “configured (or set) to” may be interchangeably used with the phrases “suitable for,” “having the capacity to,” “designed to,” “adapted to,” “made to,” or “capable of’ depending on the circumstances. The phrase “configured (or set) to” does not essentially mean “specifically designedin hardware to.” Rather, the phrase “configured to” may mean that a device can perform an operation together with another device or parts. For example, the phrase “processor configured (or set) to perform A, B, and C” may mean a generic-purpose processor (such as a CPU or application processor) that may perform the operations by executing one or more software programs stored in a memory device or a dedicated processor (such as an embedded processor) for performing the operations.

[0011] The terms and phrases as used here are provided merely to describe some embodiments of this disclosure but not to limit the scope of other embodiments of this disclosure. It is to be understood that the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. All terms and phrases, including technical and scientific terms and phrases, used here have the same meanings as commonly understood by one of ordinary skill in the art to which the embodiments of this disclosure belong. It will be further understood that terms and phrases, such as those defined in commonly- used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined here. In some cases, the terms and phrases defined here may be interpreted to exclude embodiments of this disclosure.

[0012] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of this disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

[0014] FIGURE 1 illustrates an example banknote processing system in accordance with this disclosure;

[0015] FIGURE 2 illustrates an example sensor array and magneto-active security element detection system in accordance with this disclosure;

[0016] FIGURES 3A and 3B illustrate example diagrammatic views of a circuit of a sensor in a sensor array in accordance with this disclosure;

[0017] FIGURE 4 illustrates an example diagrammatic view of a circuit for generating a voltage varying in proportion to a change in frequency provided by a signal output by the circuit of FIGURES 3A and 3B in accordance with this disclosure;

[0018] FIGURE 5 illustrates a sensor configuration in accordance with embodiments of this disclosure;

[0019] FIGURE 6 illustrates an example sensor array in accordance with this disclosure;

[0020] FIGURE 7 illustrates an example sensor array in accordance with this disclosure;

[0021] FIGURE 8 illustrates an example sensor configuration in accordance with this disclosure;

[0022] FIGURE 9 illustrates an example sensor array in accordance with this disclosure;

[0023] FIGURES 10A-10C illustrate an example sensor system architecture in accordance with this disclosure;

[0024] FIGURES 11A and 1 IB illustrate an example pulse duration and voltage determination process in accordance with this disclosure;

[0025] FIGURE 12 illustrates an example method for imaging a document including magneto-active security elements in accordance with this disclosure; and

[0026] FIGURE 13 illustrates an example electronic system in accordance with this disclosure.DETAILED DESCRIPTION

[0027] FIGURES 1 through 13, discussed below, and the various embodiments used to describe the principles of this disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of this disclosure may be implemented in any suitably arranged device or system.

[0028] As used throughout this specification, the terms currency denomination, denomination of currency, valuable document, currency bill, bill, banknote, note, check, bank check, paper money, paper currency, plastic money, plastic banknote, plastic currency, money order, coupon, ticket, and cash may be used interchangeably herein to refer to a type of a negotiable instrument or any other writing that evidences a right to the payment of a monetary obligation, typically issued by a central banking authority.

[0029] As described above, articles such as banknotes, securities, documents, and other items can have magneto-active security elements embedded therein, or attached to a surface thereon, to be used for detection or authentication. While attempts have been made to provide systems for detecting and authenticating the magneto-active security elements of such articles, use of these systems has been prohibitive due to deficient detection speeds and costly implementation. Sensor arrays can be built around magneto resistive elements, built around elements based on the Hall effect phenomenon, and / or use occurrence of an electro-magnetic field in a coil to image the magneto-active articles.

[0030] This disclosure provides embodiments of systems including detector or sensor arrays used to detect magneto-active security elements of articles such as banknotes, securities, documents, or other items. The cost-effective systems of this disclosure provide for increased detection speed of magneto-active security elements and can be implemented in a wide variety of machines or apparatuses. The embodiments of sensor arrays in this disclosure are used to obtain two-dimensional (2D) images of magneto-active articles. For example, the sensor arrays can be used for multipoint detection to create line scans as a magneto-active article is moving under or across the sensor array to sequentially image the magneto-active article and create a 2D image of magneto-active features of the banknote. This disclosure also provides detection circuitry and detection methods that provide for improved detection of articles having magnetoactive elements using controlled start pulses and strict detection phases.

[0031] The sensor systems described in this disclosure can be implemented in a wide variety of magneto-active article processing machines or apparatuses, such as ticketing machines, check scanning machines, automated teller machines, point-of-sale machines, banknote processing or recycling machines, document scanning machines, identity verification devices, etc. The sensor systems of this disclosure can be integrated into such machines or apparatuses to provide for improved detection of magneto-activesecurity elements within or on the various articles the machine or apparatus is designed to process in order to provide for authentication / verification of such articles.

[0032] For instance, FIGURE 1 illustrates an example banknote processing system 100 in accordance with this disclosure. The sensor arrays and magneto-active security element detection systems of this disclosure can be implemented in the banknote processing system 100, for example. However, it will be understood that the banknote processing system 100 is merely an example, and the sensor array and detection systems of this disclosure can be implemented in a wide variety of systems, machines, or apparatuses, as noted above.

[0033] The banknote processing system 100 may include a bezel, a chassis, an acceptor head, a banknote transport mechanism, a banknote transport path, one or more sensors to verify genuineness of inserted banknotes, a banknote storage section, and / or a banknote acceptor-dispenser module. The banknote processing system 100 of FIGURE 1 can also be used or incorporated in other systems, such as unattended payment systems, point-of-sale systems, or other currency processing apparatuses.

[0034] In various embodiments, the banknote processing system 100 is configured to verify the authenticity of an inserted banknote. The banknote processing system 100 generally has an acceptor head, a banknote transport system, and a removable banknote storage unit. Inserted banknotes are generally authenticated in a banknote accepting module using various sensors as further described in this disclosure. Once the banknote is deemed authentic and deemed acceptable, the banknote is transported further into the banknote acceptor using the banknote transport system into a banknote storage unit, which can be a removable banknote storage unit. If a banknote is rejected, it can be dispensed back out of the banknote processing system 100. When the sensor systems of this disclosure are implemented in other types of machines or apparatuses, similar processes can be used to authenticate / verify magneto-active articles, such as rejecting or accepting such articles based on outputs provided by the sensor systems.

[0035] Although FIGURE 1 illustrates an example of a banknote processing system 100, various changes may be made to FIGURE 1. Various components of the banknote processing system in FIGURE 1 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. For example, the banknote processing system 100 could include any number of escrow, storage, or recycling modules. The banknote processing system 100 could be used in automatic ticket seller machines, automated payment systems, unattended payment systems, point-of-sale systems, customer assisted payment systems, automatic teller machines, vending machines and other kiosks, or in other currency processing apparatuses / systems. In general, banknote processing systems can come in a variety of configurations, and FIGURE 1 does not limit the scope of this disclosure to any particular configuration.

[0036] FIGURE 2 illustrates an example sensor array and magneto-active security element detection system 200 in accordance with this disclosure. For ease of explanation, the system 200 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus,such as the banknote processing system 100 of FIGURE 1. However, the system 200 may be used in any other suitable systems, machines, or apparatuses.

[0037] The system 200 includes a control and processing system 202 that controls other components in the system and receives sensor outputs for processing. The system 200 also includes a multiplexer 204 that outputs signals via line 8 to each of the sensors in a sensor array 206. In various embodiments, the sensor array 206 can include a set of sensors in different configurations, such as in one or two rows. As a magneto-active article such as a banknote or other document is moved into proximity with the sensor array 206, the magneto-active security elements in the article causes a change of inductance of a coil included in the sensor, which can be measured as a frequency change in the resonant frequency of an LC circuit that includes the sensor coil. The frequency can be output via a line 4 from each sensor to the control and processing system 202, as shown in FIGURE 2. The control and processing system 202 can use these signal outputs to detect the presence of banknotes or other documents and perform 2D imaging of the magnetoactive features of the banknotes or other documents to assist with performing authentication.

[0038] Although FIGURE 2 illustrates an example sensor array and magneto-active security element detection system 200, various changes may be made to FIGURE 2. Various components of the sensor array and magneto-active security element detection system 200 in FIGURE 2 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. In general, sensor array and detection systems can come in a variety of configurations, and FIGURE 2 does not limit the scope of this disclosure to any particular configuration.

[0039] FIGURES 3A and 3B illustrate example diagrammatic views of a circuit 300 of a sensor in a sensor array in accordance with this disclosure. For ease of explanation, the circuit 300 may be described as being implemented in or involving the use of a magneto -active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the circuit 300 may be used in any other suitable systems, machines, or apparatuses.

[0040] As shown in FIGURES 3A and 3B, in this example, a coil 1 acts as the main sensing element of the sensor, the inductance of which changes when the coil 1 interacts with protective magneto-active elements of an article such as a banknote or other document when they are moved into proximity with the coil 1. The coil 1 can be a sensor array coil on a sensor PCB device. This coil 1 is connected to an oscillator on a transistor 2 in such a way that it is a part of a frequency-setting LC circuit of the oscillator. In some embodiments, the oscillator can be a Colpitts oscillator on the transistor 2. A collector of the transistor 2 is connected to a power supply conductor (+V) through a small resistor 3. Kick excitation, e.g., via a start pulse, of the oscillations can be achieved using a high speed (e.g., 3 ns) and low resistance (e.g., 0.47 Ohm) MOSFET. For example, as shown in FIGURE 3B, a start control system (Q2 and Q3) provides enabling of the oscillator in the same phase each time. When the oscillator is inactive (Q3 disabled) the capacitors Cl and C2 are discharged via a resistor (R4). When a launch / start signal is sent, Q3 connects the scheme to GND and voltage on capacitor C3 provides a kick excitation of the oscillations. The phase of oscillation is the same each time since the conditions of the start is strong and the same each time too. This makes itpossible to obtain a signal on the collector, synchronous with the oscillations of the oscillator, and the signal can be used in order to determine the frequency of the oscillations. This output signal is transmitted outward along a line 4. As described with respect to FIGURE 2, line 4 is used to send this signal output to the control and processing system 202.

[0041] An emitter of the transistor 2 is connected to a common conductor 0V through resistor 5 and capacitor 6 connected in parallel, with which a switch 7 is connected in series from the side of the common conductor. A base of the transistor 2 is connected to a source of constant bias voltage (E in FIGURE 3A) directly through the sensor coil 1. Switch 7 is closed by applying an external voltage through line 8. Thus, as shown in FIG. 3A, the circuit 300 includes a first conductor and a second conductor, where the first conductor is an input and is connected to a control electrode of the switch 7, and the second conductor is an output and is connected to the collector of the transistor 2.

[0042] While switch 7 is open, the transistor 2 is completely turned off and the circuit in which the coil 1 is connected is completely broken, so the current through the coil 1 is zero and the oscillatory circuit capacitors 6 and 9 are completely discharged. The oscillator stops and does not influence line 4, which is commonly used by all sensors of a set, as shown in FIGURE 2, for example. In some embodiments, the switch 7 can be closed based on a detection of a magneto-active article in the system, such as when an imaging sensor detects a presence of a magneto-active article, or when transportation of a magneto-active article through the system is otherwise initiated.

[0043] When a start voltage appears due to closing the switch 7, three things happen simultaneously: a shock excitation of LC oscillation, a turning on of the transistor 2, and a connection of the oscillator to line 4. This determines the initial phase of the oscillation that occurs in this circuit when the switch 7 is closed. For example, the initial phase can be equal to 7i / 2 and its initial amplitude can be equal to the bias voltage. At the same time, the transistor 2 is activated until the next opening of the switch 7.

[0044] The frequency of this oscillation changes when the inductance of the coil changes under influence of the mentioned magneto-active security elements, and this change is a primary parameter of the signal generated by the sensor. In various embodiments, the control and processing system 202 converts this change first to a voltage change, and then to a digital code change, which is the final output parameter of the array signal. In various embodiments, the method for conversion of a change in the oscillation frequency of the sensor oscillator to a change in voltage can be as follows. The switch 7 is closed by a start pulse of a strictly defined duration at the end of which the oscillation phase is analyzed. Since the initial phase of the oscillation is always the same, the phase at the moment of analysis (e.g., at the end of the start pulse) will also be the same each time while the frequency stays constant. However, if the oscillation frequency changes, for example due to the presence of the magneto-active features of a banknote, the phase at the end of the start pulse changes too, reflecting the change of frequency. A voltage that varies in proportion to the change in frequency can be generated using another circuit as described with respect to FIGURE 4 below.

[0045] Although FIGURES 3A and 3B illustrate example diagrammatic views of a circuit 300 of a sensor in a sensor array, various changes may be made to FIGURES 3 A and 3B. Various components of the circuit 300 in FIGURES 3A and 3B could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. For example, it will be understood that multiple circuits 300 can be implemented in a sensor array as a set of sensors in the sensor array. The array of sensors can also be physically implemented or arranged in various ways, such as described elsewhere in this disclosure. In general, sensors circuits can come in a variety of configurations and / or can be diagrammatically depicted in a variety of ways, and FIGURES 3A and 3B do not limit the scope of this disclosure to any particular configuration.

[0046] FIGURE 4 illustrates an example diagrammatic view of a circuit 400 for generating a voltage varying in proportion to the change in frequency provided by the signal output by the circuit 300 in accordance with this disclosure. For ease of explanation, the circuit 400 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the circuit 400 may be used in any other suitable systems, machines, or apparatuses.

[0047] As indicated above, the generation of a voltage that varies in proportion to the change in frequency is carried out using the circuit 400. The circuit 400 can be part of a frequency change detection subsystem and can act as a frequency-to-voltage converter. As shown in FIGURE 4, the circuit 400 includes a flip flop as pulse former 17. The circuit 400 also includes an analog multiplexer / demultiplexer 19 including a digital select input (S), two independent inputs / outputs (Y0 and Yl), a common input / output (Z) connected to a charging resistor 11 and an integrating capacitor 10, and an inactive LOW enable input (E).

[0048] An oscillator receiving sensor signals on line 4 as described in FIGURES 3A and 3B can provide a digital signal synchronous with the oscillations of the detected frequency that is applied to the counting input (CLK) of the pulse former 17. A start pulse is applied to the input D of the pulse former 17, the end of which determines the moment of phase analysis. As a result, a pulse Q is formed at the output of the flip-flop, the trailing edge of which occurs at the moment when the digital signal on the counting input of the pulse former 17 reaches a certain phase for the first time after the end of the start pulse. Thus, a change in said phase with a change in frequency leads to a change in the time interval between the trailing edge of the start pulse and the trailing edge of the pulse Q generated by the flip-flop.

[0049] The multiplexer / demultiplexer 19 portion of the circuitry converts this time change into a voltage change. It gets the start pulse at the input (S) and an inverted output pulse Q of the flip-flop at the inactive LOW enable input (E) . Pin Y 1 is connected to a common conductor of the system 0 V, and pin Y 0 is connected to the power supply voltage conductor. An integrating capacitor 10 in series with the charging resistor 11 is disposed between pin Z and a common conductor.

[0050] During the start pulse, the capacitor is completely discharged through pin Yl. At the trailing edge of this pulse, the capacitor is connected to the power supply voltage through the charging resistor andpin YO. So, capacitor voltage rises until the trailing edge of the pulse Q generated by the flip-flop appears. At this point, the multiplexer / demultiplexer 19 is turned off via pin E. This stops the charging of the integrating capacitor 10 and the voltage accumulated on the integrating capacitor 10 is stored, and then digitized, to convert it into a final output parameter of the sensor signal. The switch shown as part of the multiplexer / demultiplexer 19 operates according to an activation or deactivation of different channels, as shown in the table below.Table 1

[0051] The sensor array can operate in a time sharing mode, where each sensor (or group of sensors) is turned on by the start pulse only for a certain time allotted, during which the remaining sensors (or groups of sensors) are turned off and do not affect the process. The sensors can thus be activated and deactivated in sequence via switch 7 to each provide the changes in frequency as output signals to the control and processing system 202, which can then use the circuit 400 to convert the frequency signals to voltage signals.

[0052] Although FIGURE 4 illustrates an example diagram of a circuit 400 for generating a voltage varying in proportion to the change in frequency, various changes may be made to FIGURE 4. Various components of the circuit 400 in FIGURE 4 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. In general, circuits can come in a variety of configurations and / or can be depicted in a variety of ways, and FIGURE 4 does not limit the scope of this disclosure to any particular configuration.

[0053] The details of influence of magneto-active elements on coil inductance depends on the configuration of the magnetic field created by the coil. The various embodiments of this disclosure thus provide different sensor array configurations to achieve the desired magnetic field that can be affected by the magneto-active elements and to effectively detect changes in frequency.

[0054] For example, FIGURE 5 illustrates a sensor configuration 500 in accordance with embodiments of this disclosure. For ease of explanation, the sensor configuration 500 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the sensor configuration 500 may be used in any other suitable systems, machines, or apparatuses.

[0055] The example sensor configuration 500 implements a technique to modify the magnetic field by applying eddy currents in materials with high conductivity. As shown in FIGURE 5, the sensor configuration 500 includes a coil 1 and massive details, i.e., conductive plates or concentrators 13, having high conductivity, with gaps disposed between the concentrators 13. The concentrators 13 can be largeblocks of conducting material (such as a copper layer in a printed circuit board (PCB)) In this example, a signal is not created by the magnetic field directly, but by eddy currents using the illustrated and described structures.

[0056] The sensor configuration 500 and corresponding sensor arrays described herein that use electromagnetic concentrators and eddy currents are useful because they are not sensitive to, or easily influenced by, external electromagnetic fields, and can be cost-efficiently manufactured since they can be built using a PCB-based structure. In some cases, these types of sensors can be sensitive to temperature, and thus software of the system can be used to adjust detected values to compensate for temperature. In various embodiments, the transportation path and placement of the sensor array can be configured such that the magneto-active article passes within less than 1 millimeter from the sensor array (such as within 0.1- 0.5 millimeters) to provide for high detection sensitivity of the magneto-active security elements.

[0057] Although FIGURE 5 illustrates an example sensor configuration 500, various changes may be made to FIGURE 5. Various components of a sensor configuration 500 in FIGURE 5 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. In general, sensor configurations can come in a variety of configurations, and FIGURE 5 does not limit the scope of this disclosure to any particular configuration.

[0058] FIGURE 6 illustrates an example sensor array 600 in accordance with this disclosure. For ease of explanation, the sensor array 600 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the sensor array 600 may be used in any other suitable systems, machines, or apparatuses.

[0059] As shown in FIGURE 6, individual sensors similar to the sensor shown in FIGURE 5 can be arranged in an array, being located next to each other in one row. As shown in FIGURE 6, a plurality of coils 1 are arranged over the concentrators 13, and each of the plurality of coils 1 can be sequentially turned on and off during detection to image the magneto-active article across its total area. The current initiated by the control and processing system 202 goes across each plate of concentrators 13 and the gap between the plates impacts the shape of the magnetic field. When an article including magneto-active elements passes over the sensor array 600, the magnetic field is affected and its change in frequency can be output to the control and processing system 202 and recorded.

[0060] Although FIGURE 6 illustrates an example sensor array 600, various changes may be made to FIGURE 6. Various components of the sensor array 600 in FIGURE 6 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. For example, although a certain number of sensors are shown in the sensor array 600, any number of sensors could be used. As described in this disclosure, the sensor arrays can come in a variety of configurations, and FIGURE 6 does not limit the scope of this disclosure to any particular configuration.

[0061] FIGURE 7 illustrates an example sensor array 700 in accordance with this disclosure. For ease of explanation, the sensor array 700 may be described as being implemented in or involving the use of amagneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the sensor array 700 may be used in any other suitable systems, machines, or apparatuses.

[0062] As shown in FIGURE 7, individual sensors similar to the sensor shown in FIGURE 5 can be arranged in an array, being located in two rows in a plane perpendicular to the plane of the magneto-active article. As shown in FIGURE 7, a plurality of coils 1 in the two rows are arranged over the concentrators 13, and each of the plurality of coils 1 can be sequentially turned on and off during detection to image the magneto-active article across its total area. The current initiated by the control and processing system 202 goes across each plate of concentrators 13 and the gap between the plates impacts the shape of the magnetic field. When an article including magneto-active elements passes over the sensor array 600, the magnetic field is affected and its change in frequency can be output to the control and processing system 202 and recorded.

[0063] Although FIGURE 7 illustrates an example sensor array 700, various changes may be made to FIGURE 7. Various components of the sensor array 700 in FIGURE 7 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. For example, although a certain number of sensors are shown in the sensor array 700, any number of sensors could be used. As described in this disclosure, the sensor arrays can come in a variety of configurations, and FIGURE 7 does not limit the scope of this disclosure to any particular configuration.

[0064] FIGURE 8 illustrates an example sensor configuration 800 in accordance with this disclosure. For ease of explanation, the sensor configuration 800 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the sensor configuration 800 may be used in any other suitable systems, machines, or apparatuses.

[0065] As shown in FIGURE 8, the sensor configuration 800 includes a ferrite bulk 12 and a coil 1 surrounding the ferrite bulk 12. The ferrite bulk 12 can be of various ferrite materials in various embodiments of this disclosure, such as including iron oxide in combination with strontium, barium, manganese, nickel, zinc, etc. Voltage applied to the coil 1 interacts with the ferrite bulk 12 and produces an electro-magnetic field that can be affected by magneto-active articles moved into proximity with the sensor.

[0066] The sensor configuration 800 and corresponding sensor arrays described herein that use ferrite core sensors are useful because they produce a strong magnetic field and have strong sensitivity, and, thus, the transportation path and placement of the sensor array can be configured such that the magneto-active article can pass within up to 2 millimeters from the sensor array while still providing for high detection sensitivity of the magneto-active security elements. The ferrite core sensors of this disclosure can be manufactured using a PCB-based structure with ferrite. In some embodiments, a glass coating (such as a coating between 0.03-0.2 millimeters (e.g., 0.1 millimeters)) can be applied to the PCB of the sensor configuration to reduce jamming of the magneto-active article as it passes over the sensor array. In somecases, these types of sensors can have some temperature dependence, and thus software of the system can be used to adjust detected values to compensate for temperature.

[0067] Although FIGURE 8 illustrates an example sensor configuration 800, various changes may be made to FIGURE 8. Various components of the sensor configuration 800 in FIGURE 8 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. In general, sensor configurations can come in a variety of configurations, and FIGURE 8 does not limit the scope of this disclosure to any particular configuration.

[0068] FIGURE 9 illustrates an example sensor array 900 in accordance with this disclosure. For ease of explanation, the sensor array 900 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the sensor array 900 may be used in any other suitable systems, machines, or apparatuses.

[0069] As shown in FIGURE 9, individual sensors similar to the sensor shown in FIGURE 8 can be arranged in an array in two rows in the same plane as a magneto-active article. Voltage applied to each of the coils 1 interacts with the associated ferrite bulk 12 of each sensor and produces an electro-magnetic field that can be affected by magneto -active articles moved into proximity with the sensor.

[0070] Each of the plurality of coils 1 can be sequentially turned on and off during detection to image the magneto-active article across its total area. When an article including magneto-active elements passes over the sensor array 900, the magnetic field is affected and its change in frequency can be output to the control and processing system 202 and recorded.

[0071] Although FIGURE 9 illustrates an example sensor array 900, various changes may be made to FIGURE 9. Various components of the sensor array 900 in FIGURE 9 could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. For example, although a certain number of sensors are shown in the sensor array 900, any number of sensors could be used. As described in this disclosure, the sensor arrays can come in a variety of configurations, and FIGURE 9 does not limit the scope of this disclosure to any particular configuration.

[0072] FIGURES 10A-10C illustrate an example sensor system architecture 1000 in accordance with this disclosure. For ease of explanation, the architecture 1000 may be described as being implemented in or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the architecture 1000 may be used in any other suitable systems, machines, or apparatuses.

[0073] In the example architecture 1000, a sensing board 1001 includes a sensor array 1002 that comprises 32 sensors with, for instance, a 5mm aperture. These sensors are used to create line scans as a magneto-active article is moving under or in proximity to the sensors to create 2D images of magneto-active features of the magneto-active article. Each sensor is coupled to one of a plurality of oscillators 1004 included on a main board 1005. The main board 1005 also includes a plurality of channel switches (e.g., multiplexers) 1006 that are used to switch groups of sensors in the sensor array 1002 on or off. For example,as shown in FIGURE 10 A, each channel switch 1006 can be associated with a group of eight sensors 1002 (and, consequently, eight oscillators 1004). As described in this disclosure, the channels (eight channels in this example) for each channel switch 1006 can be activated and deactivated (e.g., via switch 7) sequentially and rapidly to image the magneto-active article as it passes the sensors. In various embodiments, the sensors in the sensor array are situated to cover a whole surface of the magneto-active article (e.g., a flat surface facing the sensors defined by either the short edge or the long edge of a banknote).

[0074] Each group of sensors in the sensory array 1002 is also associated with one of a plurality of frequency-to-voltage converters 1008, such as that described with respect to FIGURE 4. The frequency-to- voltage converters 1008 convert the change in frequency created by its respective group of sensors when an article including magneto-active security elements comes into proximity with the group of sensors. The plurality of channel switches 1006 and the plurality of frequency-to-voltage converters 1008 are coupled to a controller or MCU 1010 that controls the operation of the channel switches 1006 to switch sensor channels on or off, and that receives voltage signals provided by the frequency-to-voltage converters 1008.

[0075] For instance, as shown in FIGURE 10B, the MCU 1010 can control a group of oscillators 1004 via one of the channel switches 1006. As described with respect to FIGURE 10A, the group of oscillators 1004 in FIGURE 10B can be one of 4 sensor sections. Frequency signals provided by each sensor are received by a frequency-to-voltage converter 1008. For example, FIGURE 10C shows that the oscillator 1004, which can be a Sine wave oscillator, receives a signal from an activated sensor coil, and provides the wave signal to the frequency-to-voltage converter 1008. As shown in FIGURE 10B, the frequency-to- voltage converter 1008 includes a pulse forming function 1012 that forms pulse durations or widths that depends on the frequency signals received from the sensors, and a pulse width to voltage conversion function 1014 that converts the pulse widths to voltage signals for use by the MCU 1010.

[0076] The frequency measurements provided by the frequency-to-voltage converter 1008 of this disclosure are provided at high speeds and are highly accurate. As also shown in FIGURE 10B, the voltage provided by the frequency-to-voltage converter 1008 may also be processed by an analog -to-digital converter to digitize the voltage for use by the MCU 1010. These signals are then used by the MCU 1010 to detect and image magneto-active articles being transported through the system. The magneto-active articles could then be authenticated and accepted into the system, rejected, or other operations on or processing of the magneto-active articles could be performed.

[0077] Although FIGURES 10A-10C illustrate an example sensor system architecture 1000, various changes may be made to FIGURE 10. Various components of the sensor architecture in FIGURES 10A- 10C could be rearranged, omitted, combined, or further subdivided and additional components could be added according to particular needs. For example, although FIGURES 10A-10C show using a 32-sensor array, the number of sensors can be scaled down or scaled up depending on particular needs. As described in this disclosure, the sensor arrays can come in a variety of configurations, and FIGURES 10A-10C do not limit the scope of this disclosure to any particular configuration or architecture.

[0078] FIGURES 11A andl lB illustrate an example pulse duration and voltage determination process 1100 in accordance with this disclosure. For ease of explanation, the process 1100 may be described as being performed by or involving the use of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1. However, the process 1100 may be used in any other suitable systems, machines, or apparatuses.

[0079] A start pulse can be limited to a certain duration, such as about 20 microseconds (ps) (limited by scanning step and speed). For instance, as shown FIGURES 11A and 1 IB, the waveform 1102 provided as the oscillator output, and starting at an oscillator start time 1103, is limited to a start pulse 1104 having a particular duration 1106. The duration 1106 of this start pulse 1104 determines the number of oscillator periods 1108 that will be used for measurement of oscillator frequency deviation, where the initial phase 1105 of the oscillator output is constant. Fine adjusting of the start pulse duration 1106 can also be used as a calibration to setup the initial output level of each channel.

[0080] After the falling edge of the start pulse 1104, a next rising edge of oscillator output is detected, providing, as shown in FIGURES 11A and 1 IB, a resulting time interval 1110, indicating a time between the start pulse falling edge and a next rising edge of the oscillator output. It is using this time interval 1110 that the shift in the resonant frequency of the LC oscillator loop due to the presence a magneto-active article, compared to when the magneto-active article is not present, is measured. The rising edges of both the start pulse and a D-trigger output 1112 (Q) are aligned to high accuracy to correspond to the same initial phase 1105 of the oscillator output regardless of whether a magneto-active article is present or not, with the start pulses 1104 being controlled based on the MCU clock. Changes of this time interval 1110 are the results of a frequency change that forms the useful signal. The change of this time interval 1110 can be less than a duration of one oscillator period (based on a limit of the sensor’s dynamic range). The channels are scanned in this way in a staggered manner, turning off each channel between pulses on the channel to isolate reading on each channel.

[0081] The shift of the resonant frequency of the LC loop (i.e., under the influence of the magneto-active element) can be very small compared to the resonant frequency of the initial LC oscillator loop (i.e., in the absence of the magneto-active element). This delta change can be only a small fraction of one oscillator cycle. While the frequency change over one cycle of the oscillator can be very small, it can nevertheless be detectable using the systems and methods of this disclosure by accumulating the change of many cycles (for example, 600 cycles or periods 1108 during the start pulse duration 1106). The change in frequency can be measured using the change of voltage 1114 on the integrating capacitor 10 during the resulting time interval, e.g., between the falling edge of the start pulse 1104 and the falling edge of the Q pulse as also depicted in FIGURES HA and 11B. The integrating capacitor 10 voltage can then be digitized by an analog- to-digital converter for use by a processor or controller such as the MCU 1010.

[0082] Although FIGURES 11A and 1 IB illustrate an example pulse duration and voltage determination process 1100, various changes may be made to FIGURES 11A andl IB. Various components of the process 1100 could be rearranged, omitted, combined, or further subdivided and additional components could beadded according to particular needs. For example, while the process 1100 may be shown as a series of steps, various steps in FIGURES 11A andl IB could overlap, occur in parallel, occur in a different order, or occur any number of times (including zero times).

[0083] FIGURE 12 illustrates an example method 1200 for imaging a document including magnetoactive security elements in accordance with this disclosure. For ease of explanation, the method 1200 shown in FIGURE 12 is described as being performed using the system 200 and / or the sensor system architecture 1000. However, the method 1200 may be used with any other suitable device(s), system(s), and / or system architecture(s).

[0084] At block 1202, a time interval is determined from a sensor signal output created using a sensor array, the time interval being between an end of a start pulse initiated by at least one processor (e.g., MCU 1010) and a next rising edge of the sensor signal output, for example as described with respect to FIGURES 11A andl IB. As described in this disclosure, the sensor array can be the various sensor arrays described in this disclosure that are configured to generate a magnetic field influenceable by magnetically active security elements of articles.

[0085] For example, the sensor array can include a set of sensors arranged in one or more rows. Each sensor of the set of sensors can include a sensor coil operable to create the magnetic field when a voltage is applied to the sensor coil. As also described in this disclosure, an example sensor array can include a set of sensors each having a ferrite core that interacts with the magnetic field created by the sensor coil to form a sensor sensitivity zone. As also described in this disclosure, another example sensor array can have conductive plates, where the sensor coil is operable to excite eddy currents produced by the conductive plates.

[0086] As also described in this disclosure, initiation of the start pulse can be triggered based on a detection of a magneto-active article in the system, such as when an imaging sensor detects a presence of a magneto-active article, or when transportation of a magneto-active article through the system is otherwise initiated.

[0087] At block 1204, a change in a sensor oscillation frequency across the determined time interval is measured. As described in this disclosure, such as with respect to FIGURES 11A andl IB, the frequency change can be measured in a time interval defined by an end of a start pulse duration and a next rising edge of a sensor signal. As also described in this disclosure, the change in frequency can be measured using a voltage signal provided by an integrating capacitor indicating a voltage change. As described in this disclosure, the change in frequency accumulated over many cycles is quantified. This accumulated change in frequency is related to the change of the time interval between when the magneto-active feature is present or not. The length of time interval can be directly measured by the change in voltage of the integrating capacitor.

[0088] As also described in this disclosure, these steps can be performed by a frequency change detection subsystem (such as a subsystem including the frequency-to-voltage converter 1008). For example, at least one oscillator (e.g., oscillator(s) 1004) can each be coupled to a sensor in the sensor array, the sensor signaloutput can be provided to the frequency change detection subsystem by the oscillator, and the sensor signal output can be synchronous with variations of a detected frequency. In some embodiments, the oscillator is a Colpitts oscillator on a transistor, a collector of the transistor is connected to a power source through a low-resistance resistor, and an emitter of the transistor is connected to a common conductor through a capacitor and a resistor connected in parallel. Further, in some embodiments, a switch is connected in series with the capacitor and the resistor connected in parallel from a side of the common conductor; and a base of the transistor is connected to an additional DC voltage source directly through the sensor coil.

[0089] The system or apparatus can also include a first conductor and a second conductor, where the first conductor is an input and is connected to a control electrode of the switch, and the second conductor is an output and is connected to the collector of the transistor. The first conductor can be configured to receive the start pulse initiated by the at least one processor, and the second conductor can be configured to provide an output synchronous with the sensor signal output provided by the oscillator.

[0090] In various embodiments, as described in this disclosure, the determining and measuring steps can be performed by a frequency change detection subsystem, where the frequency change detection subsystem includes a flip-flop configured to receive both the start pulse and the sensor signal output, a charging resistor and a charging capacitor, and a multiplexer / demultiplexer. The multiplexer / demultiplexer can include a digital select input, a first and a second independent input and output pin, where the first independent input and output pin is connected to a common conductor, and the second independent input and output pin is connected to a power supply, a common input and output pin, and an inactive low enable input. The charging resistor and the charging capacitor can be connected in series and connected between the common input and output pin and another common conductor.

[0091] As also described in this disclosure, the multiplexer / demultiplexer can be configured to receive, at the digital select input, the start pulse, receive, at the inactive low enable input, an inverted output pulse from the flip-flop, discharge the charging capacitor through the first independent input and output pin, connect, upon reaching a trailing edge of the start pulse, the charging capacitor to the power supply through the charging resistor and the second independent input and output pin to charge the charging capacitor, and upon reaching a trailing edge of the inverted output pulse from the flip-flop, deactivate the multiplexer / demultiplexer via the inactive low enable input to stop charging of the charging capacitor.

[0092] At step 1206, voltage accumulated via the integrating capacitor is stored and digitized for use by the at least one processor. At decision block 1208, it is determined whether to activate additional sensors. That is, as described in this disclosure, the set of sensors of the sensor array can be configured to operate in a time sharing mode in which a sensor or a group of sensors is turned on by the start pulse for a predetermined amount of time. Thus, each sensor or group of sensors can rapidly and sequentially be activated and deactivated to measure the change in frequency of their respective magnetic fields as a magneto-active article is transported in proximity to the sensor array. If, at decision block 1208, it is determined that additional sensors or groups of sensors need to be activated, the method 1200 moves back to block 1202 to obtain and measure such frequency changes and store and digitize the voltage signal, fora next sensor or group of sensors. The method 1200 can loop until each sensor or group of sensors of the sensor array is activated to provide a comprehensive scan of a surface of the magneto-active article.

[0093] If, at decision block 1208, it is determined that no more sensors or group of sensors are to be activated, such as if the at least one processor determines that all sensors or group of sensors have been sequentially activated in response to a magneto-active article detection event, the method 1200 moves to block 1210. At block 1210, the at least one processor performs an imaging, detection, and / or authentication operation in which a magneto-active article can be two-dimensionally imaged, a detection status can be stored or otherwise transmitted or provided, and / or an authentication based on the measured changes in frequency against known or expected changes based on known magneto-active security elements characteristics of genuine magneto-active articles can be performed. In such authentication operations, a result can be output and / or other apparatus functions can be triggered, such as accepting a magneto-active article further into the apparatus, such as into a storage or escrow position, or rejecting a magneto-active article and dispensing the magneto-active article out of the apparatus. The method 1200 ends at block 1212.

[0094] Although FIGURE 12 illustrates one example of a method 1200 for imaging a document including magneto-active security elements, various changes may be made to FIGURE 12. For example, while shown as a series of steps, various steps in FIGURE 12 could overlap, occur in parallel, occur in a different order, or occur any number of times (including zero times).

[0095] FIGURE 13 illustrates an example electronic system 1300 in accordance with various embodiments of this disclosure. The system 1300 can be a portion of a magneto-active article processing machine or apparatus, such as the banknote processing system 100 of FIGURE 1, or of any other system, machine, or apparatus incorporating the sensor array and detection system embodiments of this disclosure. In various embodiments, the system 1300 can be, or include, the control and processing system 202. The system 1300 includes a controller (e.g., a processor / central processing unit (“CPU”)) 1302, which can be the MCU 1010, a memory unit 1304, and an input / output (“I / O”) device 1306. The system 1300 also includes at least one network interface 1308, or network interface controllers (NICs).

[0096] The system 1300 further includes one or more sensors 1310 for capturing and / or measuring data. In some embodiments, the system 1300 includes one or more imaging or optical sensors for detecting magneto-active article presence and visual imaging of magneto-active articles, as at least one of the sensors 1310, such that the imaging sensor is in communication with one or more of the other components of the system 1300. In some embodiments, as described in this disclosure, the system 1300 includes one or more sensor arrays to detect magneto-active security elements in articles to create 2D images of conductive features of the magneto-active articles, as at least one subset of the sensors 1310, such that the one or more sensory arrays are in communication with one or more of the other components of the system 1300.

[0097] The system 1300 also includes a storage drive 1312 used for storing content such as magnetoactive article data. In some embodiments, the components 1302, 1304, 1306, 1308, 1310, and 1312 are interconnected by a data transport system (e.g., a bus) 1314. In some embodiments, certain components, such as the sensors 1310, may not be connected to the data transport system 1314, and can be connected tothe processor 1302 or an interface of the processor 1302, or another component via a wired or wireless connection. A power supply unit (PSU) 1316 provides power to components of the system 1300 via a power transport system 1318 (shown with data transport system 1314, although the power and data transport systems may be separate). It will be understood that the system 1300 may be differently configured and that each of the listed components may actually represent several different components. For example, the CPU 1302 can represent a multi-processor or a distributed processing system; the memory unit 1304 can include different levels of cache memory, and main memory; the I / O device 1306 can include monitors, keyboards, touchscreens, and the like; the at least one network interface 1308 can include one or more network cards providing one or more wired and / or wireless connections to a network 1320; and the storage drive 1312 can include hard disks and remote storage locations. Therefore, a wide range of flexibility is anticipated in the configuration of the system 1300, which may range from a single physical platform configured primarily for a single user or autonomous operation to a distributed multi-user platform such as a cloud computing system.

[0098] In some embodiments, the system 1300 can use an operating system (or multiple operating systems), including various versions of operating systems provided by MICROSOFT (such as WINDOWS), APPLE (such as Mac OS X), UNIX, RTOS, and EINUX, and may include operating systems specifically developed for handheld devices (e.g., iOS, ANDROID, RTOS, and / or BEACKBERRY), personal computers, servers, and other computing platforms depending on the use of the system 1300. The operating system, as well as other instructions (e.g., for telecommunications and / or other functions provided by the system 1300), may be stored in the memory unit 1304 and executed by the processor 1302. For example, the memory unit 1304 can include instructions for causing magneto-active articles to be transported along a path within an apparatus, and for using data gathered from optical or magnetic sensors to perform magneto-active article identification and authentication.

[0099] The network 1320 may be a single network or may represent multiple networks, including networks of different types, whether wireless or wired. For example, the system 1300 may be coupled to external devices via a network that includes a cellular link coupled to a data packet network, or may be coupled via a data packet link such as a wide local area network (WLAN) coupled to a data packet network or a Public Switched Telephone Network (PSTN). Accordingly, many different network types and configurations may be used to couple the system 1300 with external devices.

[0100] One example embodiment of this disclosure can include a system that comprises at least one processor, a sensor array configured to generate a magnetic field influenceable by magnetically active security elements of magneto-active articles, and a frequency change detection subsystem configured to, using a sensor signal output, determine a time interval between an end of a start pulse and a next rising edge of the sensor signal output and measure a change in a sensor oscillation frequency across the time interval, wherein the at least one processor is configured to detect a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

[0101] In one or more of the above examples, the system is part of a banknote processing apparatus.

[0102] In one or more of the above examples, the sensor array includes a set of sensors arranged in one or more rows.

[0103] In one or more of the above examples, the set of sensors are configured to operate in a time sharing mode in which a sensor or a group of sensors is turned on by the start pulse for a predetermined amount of time.

[0104] In one or more of the above examples, each sensor of the set of sensors includes a sensor coil operable to create the magnetic field when a voltage is applied to the sensor coil.

[0105] In one or more of the above examples, each sensor of the set of sensors includes a ferrite core that interacts with the magnetic field created by the sensor coil to form a sensor sensitivity zone.

[0106] In one or more of the above examples, the sensor array includes conductive plates, wherein the sensor coil is operable to excite eddy currents produced by the conductive plates.

[0107] In one or more of the above examples, the system further comprises at least one oscillator each coupled to a sensor in the sensor array, wherein the sensor signal output is provided to the frequency change detection subsystem by the at least one oscillator, and wherein the sensor signal output is synchronous with variations of a detected frequency.

[0108] In one or more of the above examples, the at least one oscillator is a Colpitts oscillator on a transistor, a collector of the transistor is connected to a power source through a low-resistance resistor, an emitter of the transistor is connected to a common conductor through a capacitor and a resistor connected in parallel, a switch is connected in series with the capacitor and the resistor connected in parallel from a side of the common conductor, and a base of the transistor is connected to an additional DC voltage source directly through the sensor coil.

[0109] In one or more of the above examples, the system further comprises a first conductor and a second conductor, wherein the first conductor is an input and is connected to a control electrode of the switch, and the second conductor is an output and is connected to the collector of the transistor.

[0110] In one or more of the above examples, the first conductor is configured to receive the start pulse, and the second conductor is configured to provide an output synchronous with the sensor signal output provided by the at least one oscillator.

[0111] In one or more of the above examples, the frequency change detection subsystem includes a flipflop configured to receive the end of the start pulse and the next rising edge of the sensor signal output, a charging resistor and an integrating capacitor, and a multiplexer / demultiplexer including a digital select input, a first and a second independent input and output pin, wherein the first independent input and output pin is connected to a common conductor, and the second independent input and output pin is connected to a power supply, a common input and output pin, and an inactive low enable input, wherein the charging resistor and the integrating capacitor are connected in series and connected between the common input and output pin and another common conductor, and wherein, to measure the change in the sensor oscillation frequency, the multiplexer / demultiplexer is configured to receive, at the digital select input, the start pulse, receive, at the inactive low enable input, an activating inverted output pulse from the flip-flop, dischargethe integrating capacitor through the first independent input and output pin, connect, upon reaching a trailing edge of the start pulse, the integrating capacitor to the power supply through the charging resistor and the second independent input and output pin to charge the integrating capacitor, and upon reaching a trailing edge of the activated inverted output pulse from the flip-flop, deactivate the multiplexer / demultiplexer via the inactive low enable input to stop charging of the integrating capacitor and to allow voltage accumulated via the integrating capacitor to be stored and digitized via the at least one processor.

[0112] Another example embodiment of this disclosure can include a method comprising determining, using a frequency change detection subsystem, and from a sensor signal output created using a sensor array that generates a magnetic field influenceable by magnetically active security elements of magneto-active articles, a time interval between an end of a start pulse and a next rising edge of the sensor signal output, measuring a change in a sensor oscillation frequency across the time interval, and detecting a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

[0113] In one or more of the above examples, the sensor array includes a set of sensors arranged in one or more rows.

[0114] In one or more of the above examples, the method further comprises creating the magnetic field by applying a voltage to a sensor coil of each sensor of the set of sensors.

[0115] In one or more of the above examples, each sensor of the set of sensors includes a ferrite core that interacts with the magnetic field created by the sensor coil to form a sensor sensitivity zone.

[0116] In one or more of the above examples, the sensor array includes conductive plates, and wherein the sensor coil excites eddy currents produced by the conductive plates.

[0117] In one or more of the above examples, the method further comprises providing the sensor signal output to the frequency change detection subsystem using at least one oscillator each coupled to a sensor in the sensor array, wherein the sensor signal output is synchronous with variations of a detected frequency.

[0118] In one or more of the above examples, the at least one oscillator is a Colpitts oscillator on a transistor, a collector of the transistor is connected to a power source through a low-resistance resistor, an emitter of the transistor is connected to a common conductor through a capacitor and a resistor connected in parallel, a switch is connected in series with the capacitor and the resistor connected in parallel from a side of the common conductor, and a base of the transistor is connected to an additional DC voltage source directly through the sensor coil.

[0119] In one or more of the above examples, the method further comprises receiving, via a first conductor connected to a control electrode of the switch, the start pulse, and providing, via a second conductor connected to the collector of the transistor, an output synchronous with the sensor signal output provided by the at least one oscillator.

[0120] In one or more of the above examples, the frequency change detection subsystem includes a flipflop that receives the end of the start pulse and the next rising edge of the sensor signal output, a charging resistor and an integrating capacitor, and a multiplexer / demultiplexer including a digital select input, a first and a second independent input and output pin, wherein the first independent input and output pin isconnected to a common conductor, and the second independent input and output pin is connected to a power supply, a common input and output pin, and an inactive low enable input, wherein the charging resistor and the integrating capacitor are connected in series and connected between the common input and output pin and another common conductor, and wherein measuring the change in the sensor oscillation frequency includes receiving, at the digital select input, the start pulse, receiving, at the inactive low enable input, an activating inverted output pulse from the flip-flop, discharging the integrating capacitor through the first independent input and output pin, connecting, upon reaching a trailing edge of the start pulse, the integrating capacitor to the power supply through the charging resistor and the second independent input and output pin to charge the integrating capacitor, and upon reaching a trailing edge of the activating inverted output pulse from the flip-flop, deactivating the multiplexer / demultiplexer via the inactive low enable input to stop charging of the integrating capacitor and to allow voltage accumulated via the integrating capacitor to be stored and digitized via the at least one processor.

[0121] In one or more of the above examples, the sensor array is disposed on a printed circuit board.

[0122] In one or more of the above examples, the method includes quickly detecting a change of the oscillation frequency of the oscillator of a sensor under the influence of magnetically active protective elements, including starting an oscillator by the start pulse in a strictly defined initial phase, then, at the end of the start pulse, the time interval between the end of the start pulse and the moment of the nearest passage of the oscillation through a certain phase is evaluated, wherein the change of that interval reflects the change in the oscillation frequency of the oscillator.

[0123] In one or more of the above examples, the individual sensors of which are assembled into an array, located next to each other in one row.

[0124] In one or more of the above examples, the individual sensors of which are assembled into an array, located next to each other alternately in two rows in the plane of a magneto-active article.

[0125] In one or more of the above examples, the individual sensors of which are assembled into an array, located next to each other alternately in two rows in a plane perpendicular to the plane of a magnetoactive article.

[0126] While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure, as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A system comprising: at least one processor; a sensor array configured to generate a magnetic field influenceable by magnetically active security elements of magneto-active articles; and a frequency change detection subsystem configured to: using a sensor signal output, determine a time interval between an end of a start pulse and a next rising edge of the sensor signal output; and measure a change in a sensor oscillation frequency across the time interval, wherein the at least one processor is configured to detect a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

2. The system of Claim 1, wherein the sensor array includes a set of sensors arranged in one or more rows.

3. The system of Claim 2, wherein the set of sensors are configured to operate in a time sharing mode in which a sensor or a group of sensors is turned on by the start pulse for a predetermined amount of time.

4. The system of Claim 2, wherein each sensor of the set of sensors includes a sensor coil operable to create the magnetic field when a voltage is applied to the sensor coil.

5. The system of Claim 4, wherein each sensor of the set of sensors includes a ferrite core that interacts with the magnetic field created by the sensor coil to form a sensor sensitivity zone.

6. The system of Claim 4, wherein the sensor array includes conductive plates, and wherein the sensor coil is operable to excite eddy currents produced by the conductive plates.

7. The system of Claim 4, further comprising at least one oscillator each coupled to a sensor in the sensor array, wherein the sensor signal output is provided to the frequency change detection subsystem by the at least one oscillator, and wherein the sensor signal output is synchronous with variations of a detected frequency.

8. The system of Claim 7, wherein: the at least one oscillator is a Colpitts oscillator on a transistor; a collector of the transistor is connected to a power source through a low-resistance resistor;an emiter of the transistor is connected to a common conductor through a capacitor and a resistor connected in parallel; a switch is connected in series with the capacitor and the resistor connected in parallel from a side of the common conductor; and a base of the transistor is connected to an additional DC voltage source directly through the sensor coil.

9. The system of Claim 8, further comprising a first conductor and a second conductor, wherein the first conductor is an input and is connected to a control electrode of the switch, and the second conductor is an output and is connected to the collector of the transistor.

10. The system of Claim 9, wherein the first conductor is configured to receive the start pulse, and wherein the second conductor is configured to provide an output synchronous with the sensor signal output provided by the at least one oscillator.

11. The system of Claim 1, wherein the frequency change detection subsystem includes: a flip-flop configured to receive the end of the start pulse and the next rising edge of the sensor signal output; a charging resistor and an integrating capacitor; and a multiplexer / demultiplexer including: a digital select input; a first and a second independent input and output pin, wherein the first independent input and output pin is connected to a common conductor, and the second independent input and output pin is connected to a power supply; a common input and output pin; and an inactive low enable input, wherein the charging resistor and the integrating capacitor are connected in series and connected between the common input and output pin and another common conductor, and wherein, to measure the change in the sensor oscillation frequency, the multiplexer / demultiplexer is configured to: receive, at the digital select input, the start pulse; receive, at the inactive low enable input, an activating inverted output pulse from the flipflop; discharge the integrating capacitor through the first independent input and output pin; connect, upon reaching a trailing edge of the start pulse, the integrating capacitor to the power supply through the charging resistor and the second independent input and output pin to charge the integrating capacitor; andupon reaching a trailing edge of the activating inverted output pulse from the flip-flop, deactivate the multiplexer / demultiplexer via the inactive low enable input to stop charging of the integrating capacitor and to allow voltage accumulated via the integrating capacitor to be stored and digitized via the at least one processor.

12. A method comprising: determining, using a frequency change detection subsystem and from a sensor signal output created using a sensor array that generates a magnetic field influenceable by magnetically active security elements of magneto-active articles, a time interval between an end of a start pulse and a next rising edge of the sensor signal output; measuring a change in a sensor oscillation frequency across the time interval; and detecting a presence of a magnetically active security element based on the change in the sensor oscillation frequency.

13. The method of Claim 12, wherein the sensor array includes a set of sensors arranged in one or more rows.

14. The method of Claim 13, further comprising creating the magnetic field by applying a voltage to a sensor coil of each sensor of the set of sensors.

15. The method of Claim 14, wherein each sensor of the set of sensors includes a ferrite core that interacts with the magnetic field created by the sensor coil to form a sensor sensitivity zone.

16. The method of Claim 14, wherein the sensor array includes conductive plates, and wherein the sensor coil excites eddy currents produced by the conductive plates.

17. The method of Claim 14, further comprising providing the sensor signal output to the frequency change detection subsystem using at least one oscillator, wherein each of the at least one oscillator is coupled to a sensor in the sensor array, and wherein the sensor signal output is synchronous with variations of a detected frequency.

18. The method of Claim 17, wherein: the at least one oscillator is a Colpitts oscillator on a transistor; a collector of the transistor is connected to a power source through a low-resistance resistor; an emitter of the transistor is connected to a common conductor through a capacitor and a resistor connected in parallel;a switch is connected in series with the capacitor and the resistor connected in parallel from a side of the common conductor; and a base of the transistor is connected to an additional DC voltage source directly through the sensor coil.

19. The method of Claim 18, further comprising: receiving, via a first conductor connected to a control electrode of the switch, the start pulse; and providing, via a second conductor connected to the collector of the transistor, an output synchronous with the sensor signal output provided by the at least one oscillator.

20. The method of Claim 12, wherein the frequency change detection subsystem includes: a flip-flop that receives the end of the start pulse and the next rising edge of the sensor signal output; a charging resistor and an integrating capacitor; and a multiplexer / demultiplexer including: a digital select input; a first and a second independent input and output pin, wherein the first independent input and output pin is connected to a common conductor, and the second independent input and output pin is connected to a power supply; a common input and output pin; and an inactive low enable input, wherein the charging resistor and the integrating capacitor are connected in series and connected between the common input and output pin and another common conductor, and wherein measuring the change in the sensor oscillation frequency includes: receiving, at the digital select input, the start pulse; receiving, at the inactive low enable input, an activating inverted output pulse from the flipflop; discharging the integrating capacitor through the first independent input and output pin; connecting, upon reaching a trailing edge of the start pulse, the integrating capacitor to the power supply through the charging resistor and the second independent input and output pin to charge the integrating capacitor; and upon reaching a trailing edge of the activating inverted output pulse from the flip-flop, deactivating the multiplexer / demultiplexer via the inactive low enable input to stop charging of the integrating capacitor and to allow voltage accumulated via the integrating capacitor to be stored and digitized via at least one processor.

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