Abstract: A method of operating a sensor system having at least one proximity sensor, with regard to generating a trigger signal indicative of an occurrence of an operator-intended event in the presence of noise. The method includes repetitive steps of: acquiring the sensor signal at specified sampling times, comparing a value obtained as a presently sampled sensor signal with a presently valid first threshold value, generating a trigger signal if the value obtained as the presently sampled sensor signal is as large as or exceeds the presently valid first threshold value, omitting to generate a trigger signal if the value obtained as the presently sampled sensor signal is less than or equal to the presently valid first threshold value, forming a subset out of the sampled sensor signals, determining an update value for the first threshold value, and replacing the presently valid first threshold value by the update value.

Abstract: A capacitive sensor device configured for being connected between an electric heating member and a heating current supply and for using the electric heating member as an antenna electrode. The sensor device includes a common mode choke for connecting between the heating member and the current supply, and a control and evaluation circuit for determining an electrical impedance between the electric heating member and a counter electrode via a measurement node. The control and evaluation circuit includes: a third winding inductively coupled to the first and second windings of the common mode choke, a periodic signal voltage source directly connected to the third common mode choke winding, an electrical quantity measurement circuit configured to determine an electrical quantity across the measurement node, and an EMI filter network that is connected across a signal input port of the third winding and a reference input port connected to AC ground potential.

Abstract: A vehicle seat occupant classification system for use in a vehicle seat includes a weight-responsive sensor, at least one bracket member serving as a holder for the weight-responsive sensor, and an evaluation unit configured to evaluate a status of the at least one weight-responsive sensor. The bracket member is fixedly attached to the seat base. If a mechanical load at least corresponding to a first pre-determined threshold value is applied by a seat occupant, a portion of the vehicle seat comes into mechanical interaction with the at least one weight-responsive sensor, and is configured to change a status of the at least one weight-responsive sensor if a mechanical load at least corresponding to a second pre-determined threshold value is applied. Relative movement between the seat base and the at least one weight-responsive sensor is at least excluded for applied mechanical loads that are smaller than the first pre-determined threshold value.

Abstract: A method for enhancing a depth image of a scene, comprises calculating an enhanced depth image by blending a first filtered depth image with a second filtered depth image or with the original depth image. The blending is achieved by application of a blending map, which defines, for each pixel, a contribution to the enhanced depth image of the corresponding pixel of the first filtered depth image and of the corresponding pixel of either the second filtered depth image or the original depth image. For pixels in the depth image containing no depth value or an invalid depth value, the blending map defines a zero contribution of the corresponding pixel of the second filtered depth image and a 100% contribution of the corresponding pixel of the first filtered image.

Abstract: A vehicle seat sensor unit includes a seat occupancy sensor configured for wirelessly communicating with a control unit, at least one first seat detection sensor member and at least one second seat detection sensor member. The first seat detection sensor member is arrangeable in one out of a lower vehicle seat portion of a vehicle seat that is mountable in a vehicle in a removable manner, and a vehicle cabin floor, and the second seat detection sensor member is attachable to the other one of the lower vehicle seat portion and the vehicle cabin floor. The first seat detection sensor member and the second seat detection sensor member are configured to physically interact if mutually arranged within a specific distance. The physical interaction results in a detectable change of a status of at least one out of the first seat detection sensor member and the second seat detection sensor member.

Abstract: A heater element having an electrically insulating substrate, a buss layer made of a conductive material, and a resistive layer that includes a first patch of a first resistive material. The first buss layer has a first buss and a second buss extending from terminals of the heater element to a heating area of the heater element. The first resistive material is applied in a first selected location in the heating area so as to provide electrical communication between the first buss and the second buss and to enable an electrical current to flow through the first resistive material. The resistive layer includes a second patch of a second resistive material. The second patch is applied in a second selected location in the heating area so as to provide electrical communication between the first buss and the second buss, the second selected location being different from the first selected location.

Abstract: A method and circuit for measuring impedance of a sense-only capacitive sensor operated in loading mode. The method carried out by the circuit includes the steps of: combining a plurality of synchronized output signals; applying low-pass filtering to the summed output signals to generate a sinusoidal test signal; applying the sinusoidal test signal to a sensor signal voltage divider circuit and to a reference voltage divider circuit; determining amplitude and relative phase, with respect to the sinusoidal test signal, of a sensor voltage signal and a reference voltage signal; obtaining a difference voltage signal by subtracting the reference voltage signal from the sensor voltage signal; and feeding the difference voltage signal to a vector demodulator unit for obtaining a real part and an imaginary part of the complex impedance of the capacitive sensor.

Abstract: A radar system with frequency scanning beam steering is described for in-vehicle occupant detection and classification for seat-belt reminder functionality (SBR) and airbag suppression. The system includes an antenna system for which the main lobe direction (azimuth angle ö) is changing mostly linearly over frequency, a RF electronic transceiver electronic with at least one transmit channel and one or multiple receive channels with two outputs (I/Q) per channel. The data acquisition and signal processing/interpretation are made by a microcontroller system.

Abstract: A capacitance measurement circuit for determining a capacitance of a guard-sense capacitive sensor includes a microcontroller that uses a combination of several synchronized PWM outputs for generating a low distortion sine wave. The sine wave is used as a guard voltage for the guard electrode of the capacitive sensor. The capacitance value of an unknown capacitor is measured by impinging the guard voltage on the sense electrode of the capacitive sensor by a modified sigma-delta modulator unit. The digital output of the sigma-delta modulator unit is first multiplied by an XOR gate before being routed into a decimator/low pass filter. The second input of the XOR gate is driven by a square wave from a square wave generator with the same frequency as the guard voltage, but with a substantially 90° phase shift. The output of the decimator/low pass filter is indicative of the capacitance value of the unknown capacitor.

Abstract: A capacitive vehicle seat occupancy detection and classification system includes an impedance measurement circuit and a control and evaluation unit. The impedance measurement circuit is configured for providing periodic electrical measurement signals to a capacitive sensor of N different fundamental frequencies, wherein N is a natural number of at least 3, and to determine a complex impedance from each of determined sense currents in the capacitive sensor. The control and evaluation unit is configured to determine a seat occupancy class for each one of the complex impedances determined at the at least N different fundamental frequencies, and to determine a final seat occupancy class derived by a majority decision among the determined seat occupancy classes.

Abstract: A capacitive detection system for detecting occupancy of a vehicle seat includes a signal generating unit and a signal evaluation unit. The vehicle seat has a seat heater member configured for receiving time-varying output signals of the signal generating unit. The signal evaluation unit is configured to generate an output signal that is indicative of the seat heater member to be defective, if the sensed capacitance of the seat heater member is less than a second predetermined threshold value for the sensed capacitance.

Abstract: A capacitance measurement circuit for determining a sense current of a capacitive sensor which includes at least one electrically conductive sense electrode and at least one electrically conductive guard electrode. The measurement circuit includes at least one switch member that is remotely controllable by a switch remote control unit, wherein the at least one switch member in at least one closed state is configured to provide an additional electrical path between the at least one guard electrode and a reference potential.

Abstract: A capacitive sensor configured for connection between a heating element and a heating current supply comprises a common mode choke (CMC) for AC-decoupling the heating element from the heating current supply. The CMC comprises first and second inductively coupled windings, the first winding for connection between a first terminal of the heating current supply and a first terminal of the heating element and the second winding for connection between a second terminal of the heating element and a second terminal of the heating current supply. The capacitive sensor further comprises a control and evaluation circuit for injecting an AC signal into the heating element via a measurement node, measuring a voltage on and/or a current across the measurement node, and to derive an impedance between the heating element and a counter electrode from the measurement. The CMC comprises a third winding inductively coupled with the first and second windings, the third winding being operatively coupled with the measurement node.

Abstract: A vehicle seat occupancy detection system includes at least one capacitive sensor member having at least one sensing electrode, an impedance measurement circuit for determining a complex impedance or a complex admittance of the at least one sensing electrode, an evaluation unit for generating an output signal based on a determined complex admittance of the at least one sensing electrode and comparison of the determined complex admittance to at least one predetermined value, and at least one electrically conductive ground connecting member that is intentionally electrically connected to the reference electrode and that is arranged in close proximity to the at least one sensing electrode. The at least one ground connecting member and the at least one sensing electrode are galvanically separated such that, when the seat gets wet, the sensing electrode is directly electrically connected to the reference electrode by the at least one ground connecting member.

Abstract: A capacitive occupancy or proximity detector includes a heating circuit, an impedance measurement circuit connected to the heating element, and a diagnostic circuit configured for determining integrity of the heater element. The heating circuit includes a heating element, a heating current source and a common mode choke having a first and a second winding, the heating element being connectable to the heating current source via the first and second windings. The diagnostic circuit includes at least one controllable switching element coupled across the second winding, circuitry for injecting a DC current into a series connection formed by the first winding the heating element and a parallel connection of the second winding and the at least one controllable switching element, and at least one detection circuit for detecting a voltage variation across the second winding.

Abstract: A microcontroller uses a combination of several synchronized PWM outputs to generate a low distortion sine wave by summing the PWM outputs and filtering the summed signal. The sine wave is used as a guard voltage. The unknown impedance is measured by impinging the guard voltage on the sense electrode by a transistor connected in common base configuration and then transferring the sense current through the common base connected transistor to a transimpedance amplifier made out of a second transistor connected in common emitter configuration. The output voltage at the collector of the second transistor is measured by an ADC input of the microcontroller. The microcontroller translates the ADC output values into the unknown impedance to be measured by doing a software demodulation of the ADC output values. A reference impedance can be connected in parallel to the unknown impeder to eliminate gain errors of the signal sensing circuit.

Abstract: A combined heating and capacitive seat occupant sensing system comprises a common mode choke configured so as to satisfy at least one of a plurality of conditions, which is taken into account by a decision unit of the system in such a way that an influence of the common mode choke on the decision is compensated.

Abstract: A capacitive sensing device includes an antenna electrode for emitting an alternating electric field in response to an alternating voltage caused in the antenna electrode and a control and evaluation circuit configured to maintain the alternating voltage equal to an alternating reference voltage by injecting a current into the antenna electrode and to measure the current. The control and evaluation circuit includes a microcontroller with a digital output for providing a digital signal and a low-pass filter operatively connected to the digital output for generating the alternating reference voltage by low-pass-filtering the digital signal.

Abstract: An optical system for the generation of a structured light field comprises an array of light sources and a structuring unit separate from said array of light sources, said structuring unit being refractive or reflective and transforming the output of that array of light sources into a structured light illumination by collimating the light beam of each individual light source and directing each beam into the scene under vertical and horizontal angles that can be arbitrarily chosen by refraction or reflection.

Abstract: The invention relates to a seat-belt warning device comprising a device which detects a seat occupied by a passenger, a device which detects whether the seat-belt associated with a seat is being used, and a device which emits a warning signal. According to the invention, the device which detects seat occupancy by a passenger comprises an optical image-producing system comprising an image evaluation unit.