Abstract: Using software to process images and/or digital representations of paper currency to determine if currency has a value greater than the face value of the currency to any person or persons. Software that can determine from images and/or digital representations (known or unknown) numismatic value, or value greater than the face value of the currency to any person or persons and indicia of numismatic value, or increased value, including, but not limited to: ink smearing, misaligned serial numbers, misaligned seals on currency, non-matching serial numbers, off center printing, off-center cutting, paper currency of small or limited print runs, fancy serial numbers, missing or off-center watermarks, errors in security features, holograms, ultra-violet features, magnetic features, microprinting, etc. to determine a numismatic value.

Abstract: Currency processing systems, coin processing machines, coin imaging sensor assemblies and methods of making and methods of using the same are presented herein. A currency processing system is disclosed which includes a housing with a coin input area for receiving coins and coin receptacles for stowing processed coins. A disk-type coin processing unit, which is coupled to the coin input area and coin receptacles, includes a rotatable disk for imparting motion to coins, and a sorting head for separating and discharging coins to the coin receptacles. A sensor assembly is mounted to, adjacent or within the sorting head adjacent the rotatable disk. The sensor assembly includes a linear array of sensors, wherein the linear array of sensors is configured to sense coins processed by the coin processing unit, and to output a signal indicative of coin image information for processing the coins.

Abstract: Methods for determining performance information for an object located within an area include obtaining magnetic field information for the area, measuring first magnetic field data when the object is located at a first position within the area, and determining performance information for the object within the area based on the magnetic field information for the area and the first magnetic field data.

Abstract: Embodiments of the invention are directed to a locally powered smart device. A non-limiting example of the locally powered smart device includes a sensor, an energy storage communicatively coupled to the sensor, a processor communicatively coupled to the sensor and the energy storage. The processor is configured to control the sensor and the energy storage to perform multiple iterations of a tamper mitigation process, wherein each of the multiple iterations of the tamper mitigation process includes an authentication process that includes the transmission of authentication communications between the sensor and the energy storage. The processor is further configured to initiate an anti-tampering protocol based at least in part on a determination that the authentication process was unsuccessful.

Abstract: A coin detection antenna includes a substrate and a plurality of air core coils of track shape including a wiring pattern provided on the substrate. The plurality of air core coils is disposed along short-side directions of air cores of the plurality of air core coils such that a smallest coin of coins to be detected crosses at least one of centerlines of the air cores even when the smallest coin is located at any location in a detection range.

Abstract: A coin input to a deposit opening is determined a denomination by a coin identifying device, and is allocated and held in a denomination storing and dispensing device in a course of being transported to a coin transporting and distributing device. The coin of a specified denomination is sent from the denomination storing and dispensing device based on a pay-out command, and paid out to a pay-out opening by a pay out transporting device. When the holding amount of the denomination storing and dispensing device becomes full, the coin is not allocated to the denomination storing and dispensing device by the coin transporting and distributing device, but is dropped to an overflow coin slot, guided to an overflow coin guiding tube juxtaposed to the denomination storing and dispensing device and held in an overflow coin storing unit arranged on the lower side of the denomination storing and dispensing device.

Abstract: A coin handling apparatus comprises an inlet section that is provided on customer side of the coin handling apparatus and from which the coins are put in, a recognition unit that recognizes the coins put in from the inlet section, and a first ejection section that is provided on attendant side of the coin handling apparatus and to which the coins recognized as rejected coins by the recognition unit are ejected.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for delivering resources. The methods, systems, and apparatus include actions of based on measurements of amounts of a resource that are delivered from one or more supply outlets against amounts of value of electronic prepayments that have been authorized by corresponding users of mobile devices for the delivery of the resource at the one or more supply outlets, causing the one or more supply outlets to enable delivery of the resource in aggregate amounts that are not outside amounts of value of electronic prepayments that have been authorized by the corresponding users of mobile devices for the delivery of the resource.

Abstract: A contactless position and/or distance sensor for determining the distance, the spatial orientation, the material properties, or the like of a target object, and a method for operating the same, uses at least two sensor elements, which form a sensor module, Signals provided by the at least two sensor elements are jointly evaluated using at least one artificial neural network.

Abstract: A coin detection system comprises an excitation coil, a radial magnetic gradiometer, an axial magnetic gradiometer, a signal excitation source, a drive circuit, an analog front-end circuit and a processor. After the excitation coil is excited by the signal excitation source and the drive circuit, the excitation coil generates an excitation magnetic field parallel to the axial direction of a coin, and under the influence of the excitation magnetic field, the coin generates an induced magnetic field through eddy currents induced in the coin; the radial magnetic gradiometer and the axial magnetic gradiometer detect the magnetic field components of the magnetic field in the radial direction and the axial direction of the coin, and the detected signal is transmitted to the analog front-end circuit for amplification; the processor processes and then outputs the amplified signal transmitted by the analog front-end circuit, and the material, design, denomination, etc.

Abstract: This disclosure provides systems, methods and apparatus for detecting foreign objects. In one aspect an apparatus for detecting a presence of an object is provided. The apparatus includes a resonant circuit having a resonant frequency. The resonant circuit includes a sense circuit including an electrically conductive structure. The apparatus further includes a coupling circuit coupled to the sense circuit. The apparatus further includes a detection circuit coupled to the sense circuit via the coupling circuit. The detection circuit is configured to detect the presence of the object in response to detecting a difference between a measured characteristic that depends on a frequency at which the resonant circuit is resonating and a corresponding characteristic that depends on the resonant frequency of the resonant circuit. The coupling circuit is configured to reduce a variation of the resonant frequency by the detection circuit in the absence of the object.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for delivering resources. The methods, systems, and apparatus include actions of based on measurements of amounts of a resource that are delivered from one or more supply outlets against amounts of value of electronic prepayments that have been authorized by corresponding users of mobile devices for the delivery of the resource at the one or more supply outlets, causing the one or more supply outlets to enable delivery of the resource in aggregate amounts that are not outside amounts of value of electronic prepayments that have been authorized by the corresponding users of mobile devices for the delivery of the resource.

Abstract: A coin processing apparatus includes: a slit provided on a downstream-side conveyance path or at an entry of the downstream-side conveyance path in a coin drawing section for a storage to pass a coin having a coin diameter equal to or less than a diameter of a target type of coin to be drawn; a coin bias mechanism configured to bias a conveyed coin; an outer diameter sensor configured to detect whether a coin passing through the downstream-side conveyance path has an outer diameter of a target type of coin to be drawn; a material sensor configured to detect material of a coin passing through the downstream-side conveyance path; and a hole sensor that detects presence or absence of a hole of a coin passing through the downstream-side conveyance path.

Abstract: The present invention relates to an energy harvesting circuit for harvesting energy from at least one energy source.

Abstract: An object of the present invention is to provide a coin detection apparatus that includes a coin path and a light emitting diode (LED) sensor array positioned within the coin path and configured to transmit light beams within the coin path in order to detect characteristics of coins travelling through the coin path based on information from the LED sensor array and transmit data regarding a coin type based on the detected characteristics of the coin to an external application.

Abstract: A system for verifying authenticity of precious metal coins and bars includes a sensor system defining a sample region configured to receive a precious metal coin or bar therein; a sample support; and a data processor configured to communicate with the sensor system so as to receive a detection signal therefrom and to provide an output signal. The system includes a data storage device and an output display. The sensor system detects a bulk electrical property of the coin or bar. The data processor processes the detection signal and retrieves a stored physical property from the data storage device to provide an output signal that includes at least a measured value of the bulk electrical property and a corresponding range of expected values. The output display uses the output signal to display information for a user to be able to make an authenticity verification of the coin or bar.

Abstract: Systems and methods for continued runtime authentication of Information Handling System (IHS) applications. In an illustrative, non-limiting embodiment, an IHS may include one or more processors and a memory coupled to the one or more processors, the memory including program instructions stored thereon that, upon execution by the one or more processors, cause the IHS to: receive a command to execute an application; initially verify a plurality of tokens, where a first token is provided by the application, a second token is provided by an application manager, and a third token is provided by a hardware component within the IHS; and execute the application in response the initial verification being successful.

Abstract: The invention disclosed herein generally relates to a device and methods to authenticate the composition of materials, including, but not limited to gold and silver coins and gold and silver bars. The invention stimulates the natural frequencies of the tested object and then compares them to a reference dataset to confirm its authenticity. It achieves this through use of a transducer that both vibrates the object and collects amplitude response, allowing for consistent and highly accurate analysis across a broad spectrum, including ultrasonic frequencies.

Abstract: An information handling system operating a proximity based transmitting antenna power management system comprising a processor executing machine readable executable code instructions of the proximity based transmitting antenna power management system, an integrated circuit operatively connected to a first embedded proximity sensing element, a first transmitting antenna, and the processor, the first transmitting antenna mounted upon a metal chassis enclosing the processor, and the integrated circuit, the first embedded proximity sensing element having the same material composition as the metal chassis co-located with the first transmitting antenna and lying flush with the external surface of the metal chassis in a corner of the external surface of the metal chassis, and an insulating element disposed between the metal chassis and the first embedded proximity sensing element via injection molding.

Abstract: Disk image acquiring device includes a guide for guiding a peripheral surface of a disk moving in a predetermined direction along a predetermined guide line, an imaging window defining an image-taking region on the one surface of the disk, a timing sensor to take images having a detection axis traversing a moving direction of the disk and outputting a timing signal as arrival of the disk at a predetermined position on the imaging window when the peripheral surface of the disk has been detected on the detection axis, and an imager which takes an image of the one surface of the disk via the imaging window based upon the timing signal, wherein a bisector of an angle between the guide line and the detection axis is utilized as a base line, and the imaging window is extended along the base line.

Abstract: According to some embodiments of the present invention, a system for detecting counterfeit or altered coins or bullion includes a sensor system, an alternating current (AC) power supply electrically connected to the sensor system, a detection system electrically connected to the sensor system and the AC power supply, and a data processor configured to communicate with the detection system. The sensor system comprises an impedance component and a measurement circuit. The detection system is configured to determine a calibration complex impedance and a sample complex impedance. The data processor is configured to receive the calibration complex impedance and the sample complex impedance from the detection system, and provide information regarding a composition of the sample to distinguish valid coins and bullion from at least one of counterfeit or altered coins and bullion.

Abstract: This disclosure provides systems, methods and apparatus for detecting foreign objects. In one aspect an apparatus for detecting a presence of an object is provided. The apparatus includes a resonant circuit having a resonant frequency. The resonant circuit includes a sense circuit including an electrically conductive structure. The apparatus further includes a coupling circuit coupled to the sense circuit. The apparatus further includes a detection circuit coupled to the sense circuit via the coupling circuit. The detection circuit is configured to detect the presence of the object in response to detecting a difference between a measured characteristic that depends on a frequency at which the resonant circuit is resonating and a corresponding characteristic that depends on the resonant frequency of the resonant circuit. The coupling circuit is configured to reduce a variation of the resonant frequency by the detection circuit in the absence of the object.

Abstract: A coin discrimination apparatus capable of discriminating the denomination and authenticity of coins including bimetallic coins. A first coin detection sensor, located near a guide, obtains a physical characteristic of a peripheral part of a coin moved on a carrying path. A second coin detection sensor, located apart from the guide, obtains a physical characteristic about a central part of the coin. A third coin detection sensor, located on a downstream side of respect to the first sensor, obtains a physical characteristic about the peripheral part of a coin. A fourth coin detection sensor, located downstream of the second sensor and apart from the guide, obtains a physical characteristic about a central part of the coin. An additional physical characteristic about the peripheral part of the coin is obtained by cooperation of the second and third sensors when the coin reaches the third sensor.

Abstract: Currency inspection using mobile devices and attachments are provided herein, as well as methods of use. In some embodiments, an apparatus may be configured to provide selections of currencies to a user via a display of the apparatus, obtain currency attributes for a selected currency, receive currency parameters for suspect currency using a currency evaluation device that is communicatively coupled with the apparatus, the currency evaluation device having a sensor array that comprises one or more sensors that are each configured to determine at least one currency parameter, compare the currency parameters for the suspect currency to the currency attributes, and output a warning message if the suspect currency is potentially counterfeit.

Abstract: The invention provides a coin feeder for feeding coins to a coin sensor. The coin feeder comprises a hopper disc having a first surface and arranged to receive coins on the first surface, and to transport the coins along a first path towards the coin sensor. The coin feeder also comprises one or more coin deflectors to deflect coins received on the first surface from the first path if the coins are above a threshold thickness. At least one of the one or more coin deflectors comprises a rotatable member spaced from the first surface.

Abstract: A handling apparatus comprising an offset sampling module and a digital processing module is described herein. The offset sampling module is configured to provide a sampled signal by sampling at least one signal at a sampling frequency that is offset from a fundamental frequency of the signal by an offset factor; and the digital processing module configured to convert the sampled signal into a frequency domain signal. The handling apparatus further includes an authentication module to determine at least one characteristic property based at least on the frequency domain signal; and to classify the inserted item of value based on the determination.

Abstract: A method and system for reducing demand on a power grid through demand side management includes receiving assigned priorities from a customer for smart appliances and for appliances plugged into sockets of one or more smart plugs of the customer, the assigned priorities indicative of a customer-preferred sequence for disconnection of, or adjustment of power to, the appliances from the power grid. The system determines whether to disconnect or adjust power to at least one of the appliances of the customer; and selects at least one of the appliances according to the assigned priorities to reduce demand on the power grid. The system sends one or more commands, the one or more commands indicative to the one or more smart plugs to disconnect or adjust power to the selected at least one of the appliances based on selecting at least one of the appliances.

Abstract: A coin identification system and method is disclosed for determining the identity of a source coin by way of image processing. The system comprises a source coin image capture means, an image processing means, and an output that relays information to the user or sorts the coin according to its match results. The processing means compares at least one image of the source coin to a plurality of reference coin images, whereby the image of the source coin is manipulated and overlaid onto the reference coin images to determine if a match is available with a given probability. An embodiment of the system employs a coin collection and sorting device. Another embodiment contemplates a handheld electronic device that captures and processes the source coin. Both embodiments may connect to a remote server housing the reference coin information or store the information locally.

Abstract: A coin sorter machine including an encoder and a sensor assembly more accurately determines the position of coins in a coin sorting path to facilitate coin sorting. The coin sorter uses a coin size attribute to more accurately calculate the timing of interactions between coins on the coin sorting path and one or more components of the coin sorter. One such component is a diverter configured to perform an offsorting operation.

Abstract: Systems and associated methods for coin discrimination are disclosed herein. In one embodiment, a method for discriminating coins includes obtaining an electromagnetic sensor signal of a coin, generating a contour signal by digitizing the sensor signal, identifying an active interval in the contour signal by eliminating the segments of the contour signal which are close to zero, and detecting the coin approach, pivot and departure points (coin features) from the contour signal in the active interval. The coin features can be compared to known values for different coins to discriminate the coin.

Abstract: Systems and associated methods for coin discrimination are disclosed herein. In one embodiment, a method for discriminating coins includes obtaining an electromagnetic sensor signal of a coin, generating a contour signal by digitizing the sensor signal, identifying an active interval in the contour signal by eliminating the segments of the contour signal which are close to zero, and detecting the coin approach, pivot and departure points (coin features) from the contour signal in the active interval. The coin features can be compared to known values for different coins to discriminate the coin.

Abstract: A coin tester includes a coin sensor which outputs a measurement signal which is influenced by the presence of a coin. A memory device stores an impedence model of the coin sensor and the model representing an expected influence of a coin configuration model on the measurement signal. A processor computes and applies acceptance criteria to determine whether the coin falls within a predetermined coin configuration.

Abstract: A coin identification method and apparatus capable of reliably acquiring stable two-dimensional images of both surfaces of coins 217, and using the acquired two-dimensional images to perform identification and discrimination, reliably and at high speed, between coin denomination, types, dates and origins of mint. In a coin pathway, imaging devices 207a,b are positioned at an image-capture position such that images above and below the surface of passing coins are captured under illumination. The coin denomination is identified by geometric measurements of enhanced images, the coin type is identified by matching templates to enhanced images, and the coin date and mint are identified using template matching to segmented sub-images. In one embodiment, the coin identification information is used for the promotion of a coin counting service. The results are displayed in an entertaining and engaging manner.

Abstract: A coin sensor performs time-domain eddy-current testing using an inductance in one arm of a Maxwell bridge which is driven by a bipolar square wave having randomly-selected intervals between transitions, the output of the bridge being sampled at a high frequency. A processor stores a model which receives the drive signal and adjusts coefficients of the model so that the output matches the sampled measurements. Acceptance criteria are applied to the adjusted coefficients for coin classification purposes.

Abstract: Systems and methods for automatically positioning a coin sensor are disclosed herein. An auto-positioning coin sensor configured in accordance with one embodiment of the disclosure includes a coin sensor for determining a physical characteristic of an object and a moving device operably coupled to the coin sensor. The moving device can be configured to adjust the position of the coin sensor to determine the physical characteristic. Auto-positioning coin sensors in accordance with the present technology can include coin sensors that can be positioned based on a measurement of a dimension of an object.

Abstract: A coin tester includes a coin sensor which outputs a measurement signal which is influenced by the presence of a coin. A memory device stores an impedence model of the coin sensor and the model representing an expected influence of a coin configuration model on the measurement signal. A processor computes and applies acceptance criteria to determine whether the coin falls within a predetermined coin configuration.

Abstract: In a coin recognition apparatus, when an oscillator control unit applies a synthesized signal containing signals of a plurality of designated frequencies to an oscillator coil, an AD (Analog-to-Digital) converting unit converts an output signal from a receiving coil into a digital signal. A frequency expansion unit expands the digital signal on a frequency axis. A coin recognition unit recognizes a coin based on an amplitude of each signal of the designated frequency extracted from the expanded signal. Furthermore, if the coin recognition apparatus detects a coin center, which is a substantially central line on a surface of the coin, has reached a magnetic sensor based on the output signal from the receiving coil when a single frequency signal is applied to the oscillator coil, the synthesized signal is applied to the oscillator coil.

Abstract: Disclosed are various apparatus and methods for discriminating between fake and reject coins. The term ‘coin’ includes any type of monetary token or token that is associated with a value. Various different apparatus and methods are disclosed. These include a method and apparatus of applying multiple input currents of different frequencies to a coin and monitoring the apparent change in impedance of a coil or coils resulting from eddy currents induced in the layers of the coin from the multiple input currents. Other methods and apparatus relate to applying electromagnetic radiation to the coin and measuring various resulting characteristics including the amount of light fluoresced or reflected from the coin, or the absorption characteristic of the coin. Other methods and apparatus relate to measuring vibration of a coin. Other methods and apparatus relate to identifying genuine and bogus coins via particular identifying characteristics of the coins including magnetic codes/serial numbers.

Abstract: A method of operating and managing a laundry room machine that performs a washing operation and a drying operation according to a payment made by customers is provided. The method includes setting information of payments and operating conditions and setting operating conditions according to a payment additionally inserted while a drying operation is performed, receiving information of a payment insertion from the payment device and operating a predetermined operation according to the set operating conditions, and receiving information of an additional payment insertion from the payment device while a drying operation is performed and performing an additional drying operation according to the information of the additional payment insertion based on the setting operating conditions according to the payment additionally inserted while the drying operation is performed.

Abstract: A coin discrimination apparatus according to the present invention which discriminates a bimetallic coin having a ring part, and a core part provided on an inner side of the ring part and composed of a different material from that of the ring part, includes: a conveyor which conveys the bimetallic coin; a ring sensor which is arranged at a position where only the ring part of the bimetallic coin conveyed by the conveyor transits, and which detects magnetic properties; and a core sensor which is arranged at a position where the core part of the bimetallic coin conveyed by the conveyor transit, and which detects magnetic properties.

Abstract: Inductive measuring arrangement for coin validation in free-fall coin-operated devices, in which at least one elongate coil arrangement on one side of the drop path of the coins extends transversely to the drop path, two coaxial elongate coils being arranged adjacent to one another, a shell core which is E-shaped in cross section being provided, which receives the coils between its outer arms, and a central arm extending, either not at all or only partially, into the outer coil.

Abstract: A coin dispensing apparatus, which ejects coins by squeezing them substantially chordally between an element on a rotor and an ejector, has a variable height rotor (3), an improved two-part coin ejector (10a, 10b). A optical sensor for detecting coins being ejected positive detects both the presence and absence of coins in a coin path. Also, a payout device comprising a first coin dispensing device (61) including a dispensed coin type detector and a second coin dispensing device (62). The first coin dispensing device (61) is used to store coins of plurality of large denominations and is used initially for paying out an amount. The second coin dispensing device (62) is used for a single low denomination coin type and coins are dispensed from the second coin dispensing device (62) after the first coin dispensing device has been used as much as possible.

Abstract: A banknote validator takes both reflection and transmission optical measurements at different wavelengths. An emitter and sensor on one side of the banknote path are used to make a calibration measurement using light reflected from a window on the other side of the path, overlying another optical device. Each measurement is normalised on the basis of multiple measurements of different wavelengths, distributed over a substantial area, such as along the relevant scan line, preferably using a value representing the dispersion of the measurements.

Abstract: A system for validating a coin has a passageway through which the coin passes, in use; an oscillator having a component positioned relative to the passageway for the frequency and amplitude of oscillation of the oscillator to be varied, in use, by passage of the coin along the passageway; a period (or frequency) determining unit for determining the period (or frequency) of an oscillating signal provided by the oscillator when influenced by the coin and for supplying a determined period (or frequency) value; an amplitude determining unit for determining the amplitude of the oscillating signal provided by the oscillator when influenced by the coin and for supplying a determined amplitude value; and an assessing unit for assessing if the determined period (or frequency) and amplitude values lie in a predetermined window of period (or frequency) and amplitude values.

Abstract: An apparatus to record images from a coin is disclosed. The apparatus comprises a stage configured to position and rotate the coin. The stage is further configured to produce an angular positional signal output to indicate a rotational position of the coin. A first and second reflecting device are configured to concurrently image near-edge portions of both obverse and reverse sides of the coin and a recording apparatus is directed simultaneously toward an edge of the coin and the first and second reflecting devices.

Abstract: A coin discriminating device has a detecting part, a first switching part, a storage part, and a control part. The detecting part has a first sensor including a pair of coils, and an oscillating circuit, and is supplied with voltage from a power source, and in addition, outputs a detection signal varied by a coin passing between the coils. The first switching part switches magnetic connection of the coils between an in-phase connection and a reversed-phase connection a plurality of times while the coin passes between the coils. The control part compares the detection signal from the detecting part and a reference signal stored in the storage part so as to determine authentication and a denomination of the coin.

Abstract: A coin discrimination apparatus according to the present invention which discriminates a bimetallic coin having a ring part, and a core part provided on an inner side of the ring part and composed of a different material from that of the ring part, includes: a conveyor which conveys the bimetallic coin; a ring sensor which is arranged at a position where only the ring part of the bimetallic coin conveyed by the conveyor transits, and which detects magnetic properties; and a core sensor which is arranged at a position where the core part of the bimetallic coin conveyed by the conveyor transit, and which detects magnetic properties.

Abstract: A coin discriminator measures both the surface and average electrical conductivity of coins in order to distinguish genuine minted coins from fake or bogus coins such as cast coins which may be nominally of the same material as a minted coin. The conductivities are measured using a coil to induce eddy currents within the coin. The high frequency components of the eddy current are monitored to measure the surface conductivity. The low frequency components are measured to monitor the bulk or average conductivity.

Abstract: A foreign object detection apparatus has at least one pair of first and second members which are members configuring a space, in which bills to be processed are deposited, and disposed to face each other to push and sandwich the bills therebetween, the first member provided with antennas made of a copper foil and applied with a voltage from a voltage applying unit and the second member made of a conductive material and grounded to configure a virtual capacitor; a measuring unit which is disposed to measure a voltage generated according to electrostatic capacitance of the virtual capacitor; and a judging unit which judges the presence or not of a foreign object according to a difference between a prescribed reference signal and a changed output voltage from the measuring unit depending on a change in electrostatic capacitance of the virtual capacitor due to the foreign object included in the bills.

Abstract: A coin discrimination apparatus and method is provided. Coins, preferably after cleaning, e.g. using a trommel, are singulated by a coin pickup assembly configured to reduce jamming. A coin rail assists in providing separation between coins as they travel past a sensor. The sensor provides an oscillating electromagnetic field generated on a single sensing core. The oscillating electromagnetic field is composed of one or more frequency components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various frequencies are fixed, and the interaction of each frequency component with the coin can be accurately determined without the need for complicated electrical filters.