Abstract: A method of host-directed illumination for verifying the validity of biometric data of a user is provided that includes capturing biometric data from a user with an authentication device during authentication and directing illumination of the biometric data from a host authentication system during the capturing operation. Moreover, the method includes comparing illumination characteristics of the captured biometric data against illumination characteristics expected to result from the directing operation, and determining that the user is a live user when the illumination characteristics of the captured biometric data match the illumination characteristics expected to result from the directing operation.

Abstract: A skimmer apparatus comprising: a buoyant horizontal structure, a pocket-shaped net, a guide element longer than the buoyant horizontal structure and associated to the said buoyant horizontal structure, at least two ends of the buoyant horizontal structure are coupled to at least two parallel expanders, the ends of the at least two parallel expanders being attached to the pocket-shaped net (20).

Abstract: Various embodiments provide a filter for propagation delay compensation and interpolation in encoder digital signal processing. The filter can include a first low pass filter configured to reduce noise of a digital input comprising a measured angular position; a first differentiator configured to receive a filtered digital input and to calculate a speed from a difference in time of the measured angular position and a previous angular position; a second low pass filter configured to reduce noise from the speed; a second differentiator configured to receive a filtered speed and to calculate acceleration using a difference in time of the filtered speed and a previous speed; a third low pass filter configured to reduce noise of the acceleration; and a delay compensator configured to receive the filtered digit input, the filtered speed, and a filtered acceleration, and to calculate a propagation delay compensated digital output.

Abstract: A receiver coil of an inductive angular position sensor can have circuit features that become smaller than reasonable for high resolution measurement designs. This is especially true when multiple receiver coils are used, such as in a three-phase configuration, and when each of the multiple receiver coils is in a twisted loop configuration. The disclosed inductive angular position sensor utilizes different spatial frequencies for a rotor coil and the receiver coils. For example, the spatial frequency of the receiver coils may be kept smaller than the rotor coil. In this condition, the fundamental frequency of the angular position sensor is shifted to the least common multiple of the spatial frequencies, making the angular resolution of the inductive angular position sensor high, while the circuit features of the receiver coils are maintained at a reasonable size.

Abstract: In at least one general aspect, an inductive sensor can include a shaft having an axis of rotation, and a rotor physically coupled to the shaft and including a rotor coil. The rotor and the rotor coil can be aligned along a plane orthogonal to the axis of rotation. The inductive sensor can include a stator including a stator layer, an excitation coil, and an eccentricity receiver coil where the excitation coil and the eccentricity receiver coil are physically coupled to the stator layer.

Abstract: A vernier sensor including a coarse sensor and a fine sensor may require calibration to ensure accurate position measurements. Calibration may include determining coefficients for harmonics that can be added to the coarse sensor output and the fine sensor output to reduce harmonic distortion. The disclosure describes using the offset and variance of a difference signal as the basis for calibration. This approach is possible at least because the frequencies of the coarse sensor and fine sensor can be selected to reduce the complexity of these calculations.

Abstract: A position of a target is determined using a linear inductive position sensor that includes a target coil, an excitation coil, two sensors and a Vernier processor. The sensors each include two or more receive coils. The receive coils include multiple twisted loops. In the first sensor, the coils have a first period, with loops offset by first distance. In the second sensor, the coils have a second period, with loops offset by a second distance. The target coil width is a function of the first distance and the second distance. During operation, the coils output voltages in which third, fifth and/or seventh harmonics are cancelled. Based on the voltages, the sensors output respective first and second position signals, from which the Vernier processor calculates the target’s position along an axis of the position sensor.

Abstract: A method for determining authenticity of a document is provided that includes receiving, by an electronic device, an image of a document, assigning a label to the image, and obtaining vectors for each image in a subset of images. Each image is of a document and is assigned the same label as the received image. Moreover, the method includes encoding the received image into a vector, calculating a distance between the vector of the received image and each obtained vector, comparing each of the calculated distances against a threshold distance, and calculating a number of the calculated distances that are less than or equal to the threshold distance. In response to determining the calculated number is at least equal to a required number, the document in the received image is determined to be authentic. Otherwise, the received image requires manual review.

Abstract: A method of host-directed illumination for verifying the validity of biometric data of a user is provided that includes capturing biometric data from a user with an authentication device during authentication and directing illumination of the biometric data from a host authentication system during the capturing operation. Moreover, the method includes comparing illumination characteristics of the captured biometric data against illumination characteristics expected to result from the directing operation, and determining that the user is a live user when the illumination characteristics of the captured biometric data match the illumination characteristics expected to result from the directing operation.

Abstract: In at least one aspect, an inductive position sensor comprising a target. The inductive position sensor can include a stator including an excitation coil being inductively coupled to the target, and a receiver coil including a first loop connected in series with a second loop, and inductively coupled with the target such that a receiver coil voltage is generated at the receiver coil. The second loop can be offset, on the stator and relative to the first loop, by a portion of a harmonic period corresponding with a harmonic for nullification in the receiver coil voltage. The inductive position sensor can include a control unit configured to receive a plurality of receiver coil voltages including the receiver coil voltage, the control unit configured to generate an angular position signal based on the plurality of receiver coil voltages.

Abstract: In at least one general aspect, an inductive sensor can include a shaft having an axis of rotation, and a rotor physically coupled to the shaft and including a rotor coil. The rotor and the rotor coil can be aligned along a plane orthogonal to the axis of rotation. The inductive sensor can include a stator including a stator layer, an excitation coil, and an eccentricity receiver coil where the excitation coil and the eccentricity receiver coil are physically coupled to the stator layer.

Abstract: A method of host-directed illumination for verifying the validity of biometric data of a user is provided that includes capturing biometric data from a user with an authentication device during authentication and directing illumination of the biometric data from a host authentication system during the capturing operation. Moreover, the method includes comparing illumination characteristics of the captured biometric data against illumination characteristics expected to result from the directing operation, and determining that the user is a live user when the illumination characteristics of the captured biometric data match the illumination characteristics expected to result from the directing operation.

Abstract: A resonant rotor, for use in an inductive position sensor, includes a rotor core, a first rotor coil, and a rotor capacitor. The first rotor coil includes a first twisted rotor loop drawn about the rotor core and the rotor capacitor is connected in series with the first rotor coil. For a second embodiment, the first rotor coil includes a second twisted rotor loop. The first rotor coil has a first symmetry and the inductive position sensor includes a stator. An excitation coil is drawn on the stator and has a second symmetry. The first symmetry substantially corresponds to the second symmetry. A method for determining a position of an object using an inductive position sensor includes generating three electromagnetic fields using respective excitation coils, inducing voltages, respectively, in three receive coils, and determining based on voltages a position of an object coupled to a resonant rotor.

Abstract: A device and method for cleaning a tool, in particular a rotatable tool. The device includes a receptacle that has a longitudinal axis and contains at least one work portion of a tool that is to be cleaned; a plurality of brushing threads to be placed in the receptacle such that the threads are not parallel to the longitudinal axis, preferably extending at an angle or substantially perpendicularly to the longitudinal axis, with at least three thread support sections that support the brushing threads and are spaced angularly apart at regular intervals around the longitudinal axis.

Abstract: Various embodiments provide a filter for propagation delay compensation and interpolation in encoder digital signal processing. The filter can include a first low pass filter configured to reduce noise of a digital input comprising a measured angular position; a first differentiator configured to receive a filtered digital input and to calculate a speed from a difference in time of the measured angular position and a previous angular position; a second low pass filter configured to reduce noise from the speed; a second differentiator configured to receive a filtered speed and to calculate acceleration using a difference in time of the filtered speed and a previous speed; a third low pass filter configured to reduce noise of the acceleration; and a delay compensator configured to receive the filtered digit input, the filtered speed, and a filtered acceleration, and to calculate a propagation delay compensated digital output.

Abstract: Devices, systems, and method for detecting, determining and compensating for offset error arising in inductive position and torque sensors are described. In accordance with at least one embodiment, an offset coil can be configured for use within an inductive sensor and include a first trace and at least one second trace. The first trace and the at least one second trace may be drawn within a stator of an inductive sensor. The first trace and the at least one second trace may be drawn within the stator proximate to a pair of excitation coil connecting leads, drawn on a first plane within the stator, and on at least one plane substantially parallel to the first plane such that wherein an excitation coil flowing through the pair of excitation coil connecting leads induces an offset coil signal in the first trace and at least second trace.

Abstract: Systems, devices, and methods for determining a torque on a target using an inductive torque sensor are described. The inductive torque sensor may include an excitation coil, two rotors, and two or more receive coils. Each of the receive coils and the rotors may be inductively coupled. The two or more receive coils may be configured to generate a received voltage which can be approximated by a sine waveform function based on the angular changes of the coils on each rotor, the distance of the receive coils from the rotors and the distance between the receive coils. An integrated circuit may be configured to determine the torque generated on the target based on calculated differences between the angular rotation of the first rotor versus the second rotor over a given period.

Abstract: A readout circuit for use with a Wheatstone bridge sensor. At least some of the example embodiments are methods including: driving an excitation signal in parallel through a first set of sensor elements of a Wheatstone bridge sensor and refraining from driving the excitation signal through a second set of sensor elements of the Wheatstone bridge sensor; measuring response of the first set of sensor elements, the measuring response of the first set of sensor elements creates a first measurement; and then driving the excitation signal in parallel through the second set of sensor elements of the Wheatstone bridge and refraining from driving the excitation signal through the first set of sensor elements; and measuring response of the second set of sensor elements, the measuring response of the second set of sensor elements creates a second measurement.

Abstract: A method of host-directed illumination for verifying the validity of biometric data of a user is provided that includes capturing biometric data from a user with an authentication device during authentication and directing illumination of the biometric data from a host authentication system during the capturing operation. Moreover, the method includes comparing illumination characteristics of the captured biometric data against illumination characteristics expected to result from the directing operation, and determining that the user is a live user when the illumination characteristics of the captured biometric data match the illumination characteristics expected to result from the directing operation.

Abstract: A method of host-directed illumination for verifying the validity of biometric data of a user is provided that includes capturing biometric data from a user with an authentication device during authentication and directing illumination of the biometric data from a host authentication system during the capturing operation. Moreover, the method includes comparing illumination characteristics of the captured biometric data against illumination characteristics expected to result from the directing operation, and determining that the user is a live user when the illumination characteristics of the captured biometric data match the illumination characteristics expected to result from the directing operation.