Abstract: Method of detecting and overcoming degradation of image quality during a weather event and activation of windshield wipers. The method takes a high-contrast region of interest (ROI) of an image captured by a camera of a vehicle vision system, applies a Laplacian Operator that focuses on the pixel level in the ROI, and calculates a variance of the Laplacian. Images having an ROI below a predetermined variance threshold are classified or flagged as a low-quality image. Once a low-quality image is flagged, the camera settings can be readjusted in a feedback loop to compensate for the loss in quality of the captured image. This method may be stored as a software routine and implemented by a vision control module of the vision system.

Abstract: An optical measurement system includes a first light source configured to emit a first light pulse toward a target, a second light source configured to emit a second light pulse toward the target, a first detector, a second detector, and a processing unit. The processing unit is configured to determine a plurality of temporal distributions of photons included in the first light pulse and the second light pulse and detected by the first detector and the second detector after the photons are scattered by the target. The processing unit is further configured to determine, based on the plurality of temporal distributions, a distance between the first light source and the second detector.

Abstract: Aspects of the present invention provide methods, systems, and/or the like for: (1) receiving current thermal imaging data for a portion of a paper web in the paper manufacturing process; (2) determining force data for the portion of the paper web; (3) processing, to produce a first data analysis result, current thermal imaging data, the force data, and paper profile data using a machine-learning model trained with respective historical thermal imaging data, respective historical force data, and respective paper profile data for each respective prior paper breakage event in a set of prior paper breakage events; (4) generating, based on the first data analysis result, a prediction as to an occurrence of the paper break on the portion of the paper web; (5) identifying a preventative action based on the prediction; and (6) facilitating performance of the preventative action.

Abstract: A raindrop sensor device, including a substrate, a raindrop sensor element, a first light emitting diode, and an active element, is provided. The raindrop sensor element is located on the substrate and includes a first electrode and a second electrode separated from each other. The first light emitting diode is located on the substrate and is electrically connected to the first electrode. The first electrode and the second electrode are closer to the substrate than the active element. The active element is located on the substrate and is electrically connected to the first light emitting diode.

Abstract: The autonomous controller includes: a processor configured to control autonomous driving and determines whether to enable an autonomous driving mode or to convert the autonomous driving mode into a manual driving mode based on a current position of the driver's seat; and a storage configured to store data and an algorithm run by the processor. The processor controls at least one of whether to enable an autonomous driving mode, whether to restrict position adjustment of the driver's seat, or whether to hand over control authority based on a movement position in a forward or backward direction of the driver's seat or an angle of the backrest of the driver's seat.

Abstract: A concentration measurement device may include a beam splitter. The concentration measurement device may include a first optical path and a second optical path. The concentration measurement device may include a rotatable disk. The first optical path and the second optical path may reach to the rotatable disk. The rotatable disk may include at least one passing portion and at least one reflecting portion. The concentration measurement device may include a light receiver configured to detect a wavelength of the first light ant second light. The concentration measurement device may include a controller comparing the wavelengths of the first and second light. The controller compares the concentration of the object material with a reference concentration of the object material to obtain concentration control information, and the controller compares the concentration of the reference material with a normal concentration of the reference material for a concentration calibration.

Abstract: A radiation beam field shaping device is made from a 3D printed frame that contains and gives shape to a granular material with bulk density of at least 3 g/cm3 and composed of metal grains having a size between 1 ?m and 4 mm. The frame has a hole in the bottom with surrounding walls that defines the desired beam shape. In one implementation, the metal grains are composed of solid tungsten alloy ball bearings and/or tungsten alloy powder.

Abstract: Present invention relates to an entrance system (10) comprising a control arrangement (20) for controlling the automatic door operator (30). The entrance system (10) is configured to operate in any one of the following states: an opening state (OPS) wherein the one or more movable door members (D1 . . . Dm) are moving between the closed position and the opened position towards the opened position; a closing state (CLS) wherein the one or more movable door members (D1 . . . Dm) are moving between the opened position and the closed position towards the closed position.

Abstract: An electronic cigarette particularly adaptable to vaporize liquid material also having exhale filter function is disclosed herein. The exhale function is useful to prevent second hand smoke in an enclosed environment, for example. An innovative diverter valve assembly comprises a unique duckbill valve configuration diverting air through a cooker chamber and into a mouthpiece in an inhale function and diverting exhaled air around the cooker chamber in the exhale function and through a filter assembly. A preferred embodiment further introduces a unique shape to the smoking instrument being elliptical in the cross-section and tapering to proximal and distal ends.

Abstract: A fluid level determining system is for determining a fluid level of a fluid in a reservoir having an interior surface and an opposite, exterior surface. The fluid level determining system includes an emitter configured to be positioned along the exterior surface of the reservoir and emit signals into the reservoir and a receiver configured to be positioned along the exterior surface of the reservoir such that the receiver is oriented in the direction of the emitter. The receiver is configured to receive signals from the emitter passing out of the reservoir. The signals received by the receiver are attenuated relative to the signals emitted by the emitter into the reservoir. A controller is in communication with the receiver and configured to determine the fluid level based on the signals received by the receiver.

Abstract: A sensor mounting system for mounting onto a sensor mounting bracket a sensing device and a cover that covers the sensing device. The sensing device is mounted onto the sensor mounting bracket by sliding from a sensing device delivery position to a sensing device mounted position. The cover pivots relative to the sensing device from a cover delivery position to a cover locked position. When the sensing device is mounted onto the sensor mounting bracket, the cover is in the cover delivery position and contacts the sensor mounting bracket such that by pivoting the cover towards the cover locked position, the cover causes sliding of the sensing device into the sensing device mounted position.

Abstract: One example aspect of the present disclosure relates to a method for receiving input. The method can include receiving, by one or more processors, data indicative of finger placement on a three dimensional knob that is associated with a parameter. The method can include determining, by the one or more processors, a height associated with the data indicative of finger placement. The method can include determining, by the one or more processors, a gain associated with the parameter based on the height. The method can include receiving, by the one or more processors, a signal indicative of an adjustment to the parameter. The method can include causing, by the one or more processors, an adjustment to the parameter based on the determined gain and the signal indicative of an adjustment to the parameter.

Abstract: There is disclosed an automatic door installation 10 comprising: a door opening 16; and an optical door sensor comprising: a plurality of transmitters 30 arranged in a transmitter array 22, each transmitter 30 being configured to transmit an optical beam across the door opening along a respective beam path; a plurality of receivers 32 arranged in a receiver array 24, each receiver 32 being configured to generate a receiver output signal based on an intensity of light received. The plurality of receivers 32 are arranged in at least one set of receivers, the receivers of the or each set being linked so that the respective sensor output signals are combined into a compound signal for the respective set.

Abstract: A radiation therapy system comprises a magnetic resonance imaging (MRI) system combined with an irradiation system, which can include one or more linear accelerators (linacs) that can emit respective radiation beams suitable for radiation therapy. The MRI system includes a split magnet system, comprising first and second main magnets separated by gap. A gantry is positioned in the gap between the main MRI magnets and supports the linac(s) of the irradiation system. The gantry is rotatable independently of the MRI system and can angularly reposition the linac(s). Shielding can also be provided in the form of magnetic and/or RF shielding. Magnetic shielding can be provided for shielding the linac(s) from the magnetic field generated by the MRI magnets. RF shielding can be provided for shielding the MRI system from RF radiation from the linac.

Abstract: Methods, devices, and systems of a sensor surface object detection system are provided. Output from sensors of a vehicle may be used to describe an environment around the vehicle. In the event that a sensor is obstructed by dirt, debris, or detritus the sensor may not sufficiently describe the environment for autonomous control operations. The sensor surface object detection system may receive output from the sensors of the vehicle to determine whether any of the sensors are obstructed. The determination may be made by comparing the output of one sensor to another, determining whether the output of a sensor is within a predetermined threshold, or comparing characteristics of multiple sensor outputs to one another. When a sensor is determined to be obstructed, the system may send a command to a cleaning system to automatically remove the obstruction.

Abstract: A device comprising a transparent window, a photoemitter, a photodetector, and a measurement unit, wherein said photoemitter is configured to illuminate soiling particles accumulating on a surface of said transparent window, said photodetector is configured to generate a signal based on detection of light that passes through said transparent window and reflects and/or scatters from said soiling particles, and said measurement unit determines a soiling level of said transparent window based upon a measurement of said signal.

Abstract: Techniques for fast and accurate measuring test strip intensities are disclosed herein. A cassette attachment device for detecting intensity of a test strip cassette includes a strip chamber configured to accommodate at least a portion of a test strip, a light source configured to provide illumination to the test strip cassette via indirect lighting, an attaching mechanism configured to attach the device to a mobile device, and a camera window configured to transmit light signal reflected from the test strip cassette such that the mobile device can capture an image of the test strip cassette illuminated by the light source.

Abstract: An interactive input system comprises imaging devices with different viewpoints and having at least partially overlapping fields of view encompassing a region of interest. At least two of the imaging devices have different focal lengths. Processing structure processes image data acquired by the imaging devices to detect the existence of a pointer and determine the location of the pointer within the region of interest.

Abstract: A method for inspecting and detecting flaws in spheroidal products involves supplying the product to a transport element formed of pairs of supporting pads, turning the product over by means of inverting the rotation of at least one of the supporting pads, lighting the product, for example, with ultraviolet light, taking images and processing these to determine whether the product is suitable or not. The machine includes transport elements made up of pairs of freely rotating supporting pads (1) placed at regular distances on a conveyor chain, elements for controlling the rotation of the supporting pads independently as these move along, lighting devices and image capturing devices, in which the rotation control items are friction guides (25,27) placed at the bottom and top which are acted on by drive tracks (11) joined to the supporting pads.

Abstract: A transmission quantification approach that is effective at quantifying the concentration of key atmospheric gases, including water vapor and methane, does not require a background spectrum and is immune to changes between background and absorbance spectra. By using local minima and maxima in transmission of a target gas, this approach creates two spectral arrays as long as a single beam input spectra. One of these spectral arrays represents the points in wave-number space that are less absorbing points, and the other represents the more absorbing points. A concentration for a given gas is calculated by determining what reference concentration creates a residual after division by a pure gas spectrum that forces these two arrays to converge.

Abstract: A display device using infrared sensor modules that is capable of reducing power consumption and extending durability of infrared light sources and sensors and a method of driving the same are disclosed. The display device includes a display panel to display images, a plurality of infrared sensor modules to optically detect a touched position on the display panel, an infrared sensor module controller to sequentially drive the infrared sensor modules and to switch the infrared sensor modules to a low-power mode when a touch operation has not been performed within a predetermined period of time or when the display panel is in a power-saving mode, and a system to provide a state of the display panel to the infrared sensor module controller.

Abstract: An optical touch screen system includes a touch screen, an image-sensing device, and a processing device. The image-sensing device generates a plurality of light-shielding information of an object at a plurality of time points. The processing device coupled to the image-sensing device includes a computing unit calculating a projected size difference value according to the plurality of light-shielding information, wherein the projected size difference value is a difference value between the projected sizes of the object on the touch screen at two different time points.

Abstract: A method in an electronic device, the method includes projecting infrared (“IR”) light from a plurality of light emitting diodes (“LEDs”) disposed proximate to the perimeter of the electronic device, detecting, by a sensor, IR light originating from at least two of the plurality of LEDs reflected from off of a person, and carrying out a function based on the relative strength of the detected IR light from the LEDs.

Abstract: In an optical measuring device, the visual observation section includes: a white light source which emits white light; a first objective lens arranged between the white light source and measurement object, through which the white light emitted from the white light source and return light from the measurement object transmit; a plurality of tube lenses which change a magnification of the return light passing through the first objective lens to a predetermined magnification; and a lens switching mechanism which can selectively switch the tube lenses so as to select one of the tube lenses to be arranged on the return light, and the special observation section includes: a special light source which emits special light; and a second objective lens arranged between the special light source and measurement object, through which the special light emitted from the special light source and return light from the measurement object transmit.

Abstract: A method in an electronic device, the method includes projecting infrared (“IR”) light from a plurality of light emitting diodes (“LEDs”) disposed proximate to the perimeter of the electronic device, detecting, by a sensor, IR light originating from at least two of the plurality of LEDs reflected from off of a person, and carrying out a function based on the relative strength of the detected IR light from the LEDs.

Abstract: A method in an electronic device, the method includes projecting infrared (“IR”) light from a plurality of light emitting diodes (“LEDs”) disposed proximate to the perimeter of the electronic device, detecting, by a sensor, IR light originating from at least two of the plurality of LEDs reflected from off of a person, and carrying out a function based on the relative strength of the detected IR light from the LEDs.

Abstract: Disclosed is a device for optically determining a concentration of alcohol and carbohydrates in a liquid sample. The device includes at least a first and a second light source arranged for exposing the liquid sample in a wavelength range between 750 nm and 1000 nm, a spectrometer arranged to determine a first and a second light intensity by measuring the light from the first and the second light source, a processing unit which is connected to the spectrometer and which is arranged to determine an absorption value of the liquid sample from a comparison of the first and the second light intensity with a reference value. In certain aspects, the device may further include a processing unit that calculates concentrations of alcohol and/or carbohydrates and at least two polarization filters.

Abstract: The present disclosure provides novel measurement techniques based on moiré techniques and optical frequency conversion. For example, in the IR realm, the configuration can be any moiré configuration, the detector is an IR detector, and the light source can be at any wavelength. The optical configuration, the detector, and the type of light source depend on the physical properties of object/scene and the parameter(s) to be measured.

Abstract: A method and system that measure the head position of a driver in a vehicle include an infrared lamp that is disposed on a driver B-pillar and transmits an infrared signal and an infrared receiving sensor that is disposed on a passenger A-pillar to receive infrared signal from the infrared lamp. In addition, a plurality of infrared lamps are disposed on the headrest of the driver's seat and transmit infrared signals and an infrared receiving sensor is disposed on a dashboard disposed in front of a steering wheel to receive infrared signals from the infrared lamps on the headrest. A controller operates the infrared lamps to transmit infrared signals and measures the head position of a driver based on infrared signals received by the infrared receiving sensors.

Abstract: A system for determining a sash panel position. An example system includes a linear array of light emitting elements spaced at equal distances from one another mounted on a fume hood frame. The light emitting elements generate a light path towards a sash panel such that the sash panel blocks the light path when positioned at the light emitting element. A linear array of light sensing elements is spaced at equal distances from one another on a side opposite the sash panel. The light sensing elements receive the light path generated by corresponding light emitting elements when the sash panel does not block the light path. The light sensing elements may be on modules having shift registers with bits corresponding to the light sensing elements. The shift register stores a state of the light sensing element and outputs a series of bits indicating the state of each light sensing element.

Abstract: A closed path infrared sensor includes an enclosure, a first energy source within the enclosure, at least a second energy source within the enclosure, at least one detector system within the enclosure and a mirror system external to the enclosure and spaced from the enclosure. The mirror system reflects energy from the first energy source to the at least one detector system via a first analytical path and reflects energy from the second energy source to the at least one detector system via a second analytical path. Each of the first analytical path and the second analytical path are less than two feet in length.

Abstract: Toner sensor modules are provided. In one aspect, a toner sensor module has a first light source emitting a first light, a first light sensor that generates a sensed light signal that is indicative of a sensed light, and a frame. The frame positions the light source to illuminate a target area from a first side a plane that is normal to the target area so that illuminated portions of any toner particles at the target area direct a reflected a portion of the first light into the first side and positioning the first light sensor on the first side of the plane to which toner particles at the target area direct the reflected portion of the first light.

Abstract: In an optical position detection device, when light source sections emit detection light, a light detecting section detects detection light reflected from a object to detect the coordinates of the object. When seen from the detection space, the light detecting section is located inward from a plurality of light source sections, and each of the plurality of light source sections includes first and second light emitting elements. Therefore, the position of the object can be detected on the basis of a comparison result of the received light intensity in the light detecting section when the first light emitting element is turned on and the received light intensity in the light detecting section when the second light emitting element is turned on in both the case where the object is located outside a region between the light source sections and the case where the object is located inside the region.

Abstract: An infrared sensor module includes a first infrared sensor that includes a first light emitting unit configured to emit infrared light to an object and a first light receiving unit configured to detect an amount of infrared light reflected from the object, a second infrared sensor that includes a second light emitting unit configured to emit infrared light to the object and a second light receiving unit configured to detect an amount of the infrared light reflected from the object, and a controller to measure reflectivity of the object using a peak output voltage of the first light receiving unit, and to measure a distance to the object using not only the measured object reflectivity but also an output voltage of the second light receiving unit. As a result, the distance from the infrared sensor to the object can be correctly measured irrespective of the reflectivity of the object.

Abstract: Motions or gestures can provide input to an electronic device by capturing images of a feature used to provide the motions or gestures, then analyzing the images. Conventional cameras have a limited field of view, creating a “dead zone” near the device that is outside the field of view. Various embodiments utilize an array of detectors positioned behind a display screen that are configured to operate as a large, low resolution camera. The array can resolve objects within a distance of the device sufficient to cover at least a portion of the dead zone. In some embodiments the device can include one or more infrared (IR) emitters to emit IR light that can be reflected by an object in the dead zone and detected by the detectors. The use of multiple emitters at different locations enables at least some depth information to be determined from the array images.

Abstract: A process and apparatus for analyzing quantities of grain in-line and separating the grain into batches on the basis of one or more grain parameter values is disclosed. The grain is separated in-line on the basis of the grain parameter value thus allowing the grain to be separated into homogeneous batches.

Abstract: A closed path infrared sensor includes an enclosure, a first energy source within the enclosure, at least a second energy source within the enclosure, at least one detector system within the enclosure and a mirror system external to the enclosure and spaced from the enclosure. The mirror system reflects energy from the first energy source to the at least one detector system via a first analytical path and reflects energy from the second energy source to the at least one detector system via a second analytical path. Each of the first analytical path and the second analytical path are less than two feet in length.

Abstract: A system for surface resin thickness measurement on a fiber reinforced polmer composite includes a holding fixture configured to match a contour of a composite part in which a resin thickness is to be measured, a plurality of infrared measurement sensors in the holding fixture which can be moved along the surface to create a map of the surface to be measured, a computer-based data acquisition system interfacing with the plurality of infrared measurement sensors and calibration software supporting the data acquisition system.

Abstract: A disinfection system for liquids is provided that features an irradiation chamber for accommodating a liquid to be disinfected. A UV-radiator with a cladding that is transparent to UV-light is arranged in the irradiation chamber such that the UV-radiation emitted by the UV-radiator may penetrate the liquid. A first UV-sensor is arranged in the irradiation chamber such that a first attenuation characteristic with respect to the UV-light emitted by the UV-radiator may be measured with the first UV-sensor, wherein the first attenuation characteristic comprises a first aging characteristic and a first liquid attenuation characteristic.

Abstract: This invention describes a system for generating multiple simultaneous tunable electron and photon beams and monochromatic x-rays for all field simultaneous radiation therapy (AFSRT), tumor specific AFSRT and screening for concealed elements worn on to the body or contained in a container. Inverse Compton scattering renders variable energy spent electron and tunable monochromatic x-rays. It's spent electron beam is reused for radiation with electron beam or to generate photon beam. Tumor specific radiation with Auger transformation radiation is facilitated by exposing high affinity tumor bound heavy elements with external monochromatic x-rays. Heavy elements like directly iodinated steroid molecule that has high affinity binding to estrogen receptor in breast cancer and to iodinated testosterone in prostate cancer or with directly implanted nanoparticles into the tumor are exposed with tuned external monochromatic x-rays for tumor specific radiation therapy.

Abstract: The invention relates to a NDIR two beam gas analyser in which infrared radiation is guided by modulation in an alternating manner through a measuring chamber and a reference chamber and is subsequently detected, a measurement signal being produced due to the analysis which determines the concentration of a measurement gas component present in the measurement chamber.

Abstract: The disclosure relates to a detection device for detecting movement of a live insect located within a seed or grain. The device may include a light source with a masking arrangement to block stray light. It may also include a detection region sized to contain at least one seed. Finally, the device may include a detection instrument able to detect changes in light from the light source caused by movement of an insect within the seed. The disclosure also relates to a method of detecting an insect in a seed. First, one may pass light through the seed. Then one may detect light passed through the seed and, based on the light passed through the seed, determine whether or not an insect within the seed is moving.

Abstract: A non-destructive evaluation system and method is provided for detecting flaws in an object. The system includes a lamp for impinging the object with optical pulses and a focal plane array camera configured to capture the images corresponding to evolution of heat due to an impact of the optical pulses in the object. The system also includes an image acquisition system for capturing data corresponding to the images from the focal plane array camera. Both transmission mode imaging and reflection mode imaging techniques are used in an exemplary embodiment. A time of flight analysis system is also provided for analyzing the data from both transmission mode imaging technique and reflection mode imaging technique. The data from transmission mode imaging is used to determine thickness values at different points in the data and for determining location of flaws using the thickness values. The data from reflection mode imaging is used for determining depth of these flaws.

Abstract: There is disclosed an dual use RF directed energy weapon and imager. A generator may provide a first beam of RF electromagnetic energy which may be directed to an object by a beam director. An imager may form an image of the object. The imager may share an aperture defined by the beam director.

Abstract: S-band, C-band or X-band microwave powered linear accelerators capable of delivering therapeutic photon and electron beams are mounted to a gantry with extensions to hold multiple accelerators and are combined with a kV CT for 3-D conformal—IMRT and IGRT to treat a patient by SSD or SAD methods and in a full circle. The invention's tertiary collimator system consists of semi-automated reusable custom field shaping with tungsten powder or melted Cerrobend blocks. The beam's intensity modulation is by means of simultaneous but independently operating multiple accelerators. This system's multiple accelerators enable to avoid interrupted subfractionated radiation therapy to each treatment fields. Hence its effective dose rate at the tumor site is high. The improved radiobiology reduces the total radiation dose to treat a tumor, reducing the incidence of developing second primary tumors is also minimized.

Abstract: Apparatus and methods for detecting adhesives. The apparatus includes an adhesive sensor having a photodiode sensitive to infrared radiation at different wavelengths. The adhesive sensor may sense infrared radiation thermally emitted from a sufficiently hot adhesive. Alternatively, the adhesive sensor may sense infrared radiation from first and second near infrared diodes that emit at different wavelengths that are reflected with different intensities from an adhesive that is at a temperature insufficient to emit infrared radiation at an intensity to be readily detectable. A visible light source may be provided for targeting and focusing the adhesive sensor.

Abstract: A method for detecting a phenomenon affecting visibility generated by an automotive vehicle, comprising the steps of emitting a first beam of light, which beam of light can be reflected by an obstacle; emitting a second reference beam of light using a second emitting source; receiving on a receiver the reflected beam of light resulting from the first beam of light being reflected by an obstacle, and the second beam of light sent directly to the input of the receiver; generating one or more detection signals as a function of a combination of the reflected beam of light in the event of an obstacle and a reference beam; and comparing the modulation of one or more detection signals generated using reference data. According to the invention, the first and second beams of light are infra-red beams, and they are directed towards the rear of the vehicle.

Abstract: A medical accelerator system consisting of coplanar and non-coplanar beams, on line magnetic resonance anatomic and functional imaging and cone beam computed tomographic imaging for single session image guided all field simultaneous radiation therapy and radiosurgery is provided. This system enables single session simulation, field-shaping block making, treatment planning, dose calculations and treatment of tumors. The radiation exposure time to the tumor and the normal tissue is reduced to a few seconds to less than a minute. In filed intensity modulated radiation is rendered by combined divergent and pencil beam, multiple smaller fields within a larger field, selectively varying beam's energy, dose rate and beam weight. Since all the treatment fields are treated simultaneously the dose rate at the tumor site is the sum of each of the converging beam's dose rate at depth. This super-high biological dose rate impairs the lethal and sublethal damage repair.

Abstract: A paper-sheet recognition apparatus that acquires information from a paper sheet and recognizes the paper sheet based on the information. The apparatus includes one or more light emitting units that output first to n-th lights (n>2) of different wavelengths; an emission controller that performs emission control of the light emitting units; a light receiving unit that receive a component of a light, which has been emitted from the light emitting unit and then reflected from and/or transmitted through the paper sheet; and a paper-sheet recognition processor that recognizes the paper sheet by using an optical signal received by the light receiving unit. The emission controller performs the emission control of the light emitting units such that the number of light emissions per one emission cycle with respect each of to the first to n-th lights differs depending on information desired to be used in recognizing the paper sheet.

Abstract: Apparatus for measurement of a sample comprises means for generating electromagnetic radiation comprising a photoconductive device, the generating means is arranged to generate an output signal comprising electromagnetic radiation in dependence upon radiation received by the photoconductive device and to transmit the output signal towards a sample space, the apparatus further comprises a first radiation source and a second radiation source, arranged such that the radiation received by the photoconductive device comprises a mixture of radiation from the first radiation source and radiation from the second radiation source, control means for varying the frequency of the electromagnetic radiation of the output signal by varying the temperature of the first radiation source and/or the temperature of the second radiation source, and detecting means for detecting a response signal.