Abstract: RF modulation spectroscopy of a near-infrared tunable laser diode source is used to determine the oxygen concentration in a sample medium. A reference cell containing a known concentration of oxygen is used to calibrate the apparatus as well as to lock the laser on an oxygen absorption line. The temperature of the reference cell is monitored from which the pressure in the reference cell can be determined. Both the temperature and the pressure in the sample cell are monitored, either directly using independent transducers or indirectly using spectroscopic techniques. The oxygen content of the sample is determined, correcting for both temperature and pressure effects.

Abstract: A system for scanning a room to find the location of target devices, and then locking onto them with stationary directed beams for two-way communication. In one embodiment, a base system in each room comprises an IR source/receiver combination plus an LCD display panel which covers the source/receiver and is addressed in such a way as to open up dynamic apertures through which IR radiation in a scanning mode can be directed toward any particular location in the room. When a device at that location senses that it is being irradiated by the base station, the targeted device responds by emitting a coded packet of IR pulses. This system takes advantage of the higher bandwidth communication that can be obtained with point-to-point communications, while still allowing for multiple devices at arbitrary locations in the same room.

Abstract: A variable filter spectrophotometer, for use with sample and reference; has a main member, a filter unit, a drive, a detector, a light distribution system, and a clamping circuit. The main member defines first and second beam paths, which are intersected by the filter unit. The filter unit has filtering and opaque portions. The filter unit is continuously movable relative to the beam paths in a repeating cycle from a first filtering relation in which the filtering portion is interposed in the first beam path and the opaque portion completely blocks the second beam path, to a first dark relation in which both beam paths are blocked, to a second filtering relation in which the filtering portion is interposed in the second beam path and the first beam path is completely blocked, and to a second dark relation in which both beam paths are completely blocked. The filtering portion is variably transmissive along a direction of movement of the filter unit.

Abstract: A portable refrigeration gas analyzer employs infrared spectroscopy to detect adulterant refrigerant gases in existing R12 refrigeration systems. The analyzer can detect contaminants such as R134a, R22, and butane in concentration as low as 1% by volume. A rugged opto-acoustical infrared narrow band sensor is suitable for field use in the repair of refrigeration systems.

Abstract: A thermal image detecting system includes a moving part having pyroelectric thermal detection element, a chopper for opening/closing a path of infrared rays and a chopper temperature detection element, a rotating section for rotating the moving part, a drive control section for driving the chopper and the rotating section, a band amplifier for amplifying a detection signal from the pyroelectric thermal detection element, a timing output section for outputting a signal synchronous with an opening/closing operation of the chopper, a peak detection section for successively holding the maximum value and the minimum value of a signal from the band amplifier, and an operational processing section for performing operational processing on a thermal image signal on the basis of a difference between the maximum value and the minimum value or a difference between a reference signal from the band amplifier in a closed state of the chopper and the maximum value, or the minimum value and the temperature of the chopper.

Abstract: A thermal imaging system (10) contains a focal plane array (14) including a plurality of thermal sensors (50) mounted on a substrate (52). The focal plane array (14) generates both a reference signal which represents the temperature of the substrate (52) and a biased signal corresponding to the total radiance emitted by a scene (11). Electronics (16) process the reference signal and the biased signal to obtain an unbiased signal representing radiance differences emitted by objects in the scene (11). A thermoelectric cooler/heater (38) may be provided to optimally adjust the temperature of the substrate (52) to improve overall image quality. Each thermal sensor (50) contains an electrode (66 and 68) that electrically couples the thermal sensor (50) to the substrate (52) and also allows the thermal sensor (50) to deflect, contact, and thermally shunt with the substrate (52).

Abstract: A thermal image detector and, more particularly, linear or matrix pyroelectric detectors. These detectors work differentially in successive phases of illumination and masking via a shutter that is synchronized with signal processing circuits. The detector generates differential measurement signals representing variations of pyroelectric signals recorded during a cycle comprising a masking phase and an illumination phase. To eliminate fixed pattern noise, it is proposed to make the measurements by difference between two successive cycles of masking and illumination, the order of the illumination/masking cycles being reversed between the two cycles but the measurements being made identically in both cycles. A memory records the signals during a cycle. A subtractor subtracts the signal of the current cycle from the signal recorded in the previous cycle.

Abstract: Disclosed is a picture information memory device, including a picture information memory means for generating electric charges corresponding to the intensity of write-in light incident thereon, and for holding the generated electric charges as polarized charges, an exposing means for exposing the picture information memory means to light from an object, and an alternating-current bias voltage applying means for applying an alternating-current bias voltage having a desired frequency to the picture information memory means, whereby electric charges generated by the portion of the object light the intensity of which varies at the same frequency as that of the alternating-current bias voltage, are selectively accumulated from the entirety of electric charges generated by the object light incident on the picture information memory means, and held as the polarized charges in the picture information memory means.

Abstract: An instrument is provided for measuring the temperature of an object from infrared radiation emitted by the object. The instrument includes a radiation detector, a temperature indicating device connected to the detector, and a modulator disposed in a path of a radiation beam from the object for converting the beam into a series of pulses when the modulator is vibrated in and out of the path. The modulator includes a primary piezoelectric element adapted to vibrate when subjected to driving signals at a frequency related to the resonant frequency of the modulator, and a secondary piezoelectric element connected with and driven by the primary piezoelectric element. The secondary piezoelectric element is electrically insulated from the primary piezoelectric element. The modulator also includes a blocking element connected with the secondary piezoelectric element and disposed to move in and out of the path of the beam.

Abstract: Infrared radiation emitter units for gas analyzers and other applications. The emitter has a substrate with a film of electrically resistive, emissive material on one of its surfaces. The emitter is so mounted on an emitter unit base that it can freely expand as the emitter heats up. A lead frame commutator, employed to electrically connect the emitter to an external power source, also facilitates the assembly of the unit. A component with a plated, parabolic surface collimates and focuses into an appropriate beam the energy generated by the emitter.

Abstract: A spectrophotometer is described, comprising a single light source, a single detector, optics for dually and alternatively reading a sample and a reference, and only one moving part. That moving part is a chopper containing multiple pass-through apertures, each filled with a unique bandpass filter to select wavelengths to specifically illuminate the sample or reference. To inform the spectrophotometer whether and when it is reading the sample or the reference, trigger means are provided in at least twice the number of the pass-through apertures.

Abstract: RF modulation spectroscopy of a near infrared laser diode source is used to determine the amount of a target substance in a breath sample. In this type of modulation the laser output is modulated to produce sidebands displaced from the laser carrier by the modulation frequency. The modulated beam is passed through a gas sample which differentially absorbs the sidebands, the result of which is the conversion of some of the laser frequency modulation into amplitude modulation which is subsequently detected using a broadband photodetector. In certain tests, the target substance is a particular isotope, whose concentration is measured as an isotope ratio. In order to measure the presence of first and second isotopic species, provision is made to provide laser illumination at characteristic wavelengths for absorption lines for the first and second isotopic species of the gas.

Abstract: An infrared detector with a pyroelectric detector element and an AC amplifier has a chopper control circuit that enables the detector to sense either a moving person or temperature. When used to sense a moving person, the chopper control circuit stops operation of the chopper, and the gain of the amplifier is increased. When used to sense temperature, the chopper is operational, the gain of the amplifier is decreased, and total infrared energy is measured.

Abstract: An infrared imaging arrangement using a chopping device for periodically blocking exposure of an array of detector elements responsive to infrared energy by using a plurality of individually-mounted cells. There is a non-reciprocating rotary mechanism used for moving the cells substantially orthogonal to the array in such a manner that constant orientation of the cells is maintained in order to expose the array to energy via the cells. Since the cells orientation is maintained, the shift of energy relative to the array increases the arrays ability to resolve spatially sources of energy. There is also an infrared blocking piece used for blocking the infrared energy from impinging on the array.

Abstract: A detector for detecting hot spots that includes an infrared sensor and a scanning component. The infrared sensor is fixedly mounted on a housing and is oriented to have a field of view of at least part of the region of interest. The scanning component is mounted in front of the infrared sensor and blocks most of the field of view of the infrared sensor and has a moving aperture that exposes the infrared sensor to a small area of the region at one time. The moving aperture provides a small instantaneous field of view and over time exposes the sensor to a much larger area.

Abstract: An optoelectronic viewing system for imaging a field of view on a monitor includes a telescope for generating an optical image of the field of view, a scanning device for electronically scanning the optical image and an electronic evaluation unit for processing the scanning signals and displaying the image on the monitor. In order to create a field of view which is large enough for surveillance with a long-range viewing system that has sufficient resolution, a mirror system for pivoting the direction of beam incidence in the vertical and horizontal direction is placed ahead of the telescope. The mirror system is driven for reproducibly and consecutively passing through a succession of fixed predetermined pivoted positions. The scanned image signals obtained from the individual pivoted positions are combined into a field of view.

Abstract: A method and apparatus for the detection of pits and abnormalities in various stone fruits. The apparatus transmits a first plurality of beams of light (18) across inspection zone (14) and transmits a second plurality of beams of light (22) across inspection zone (14) in a direction opposite to beams of light (18). As a stone fruit (10) passes through inspection zone (14), a first plurality of sensors (32) and a second plurality of sensors (34) detect the variations in the intensity of the transmitted beams of light. The light transmittance and reflectance characteristics of the stone fruit are analyzed to detect the presence of a pit or internal or external abnormality.

Abstract: Pyrometric temperature measurement of molten masses arranged in a vacuum involve the problem that the material of the molten mass deposits on mirrors, windows and other optical means so that the radiation, on its way to the pyrometer, is ever more absorbed. For preventing vapor depositions in the path of radiation, a matter filter having a rotating vane wheel is arranged between the container for the molten mass and the pyrometer. The radiation passes through the gaps between the vanes. Molecules of the molten material are caught by the vanes. Accordingly, a mirror behind the matter filter is kept free of undesired vaporization and transmits radiation to the pyrometer.

Abstract: An apparatus and method for the identification of one or more anesthetic or other gases included in the respiratory air of a patient, said identification being effected within the infrared range 3-4 .mu.m. The appratus comprises a radiation source (4), a chamber (1) for receiving therein a gas or gases to be examined, an optical filter (7) for passing the radiation exiting the chamber therethrough, an optical focusing device (12) through or via which the incoming radiation travels, a radiation detector (10) and a measuring processor (19) which performs the measuring and identification. The transmission band of the optical filter (7) or a combination of successive filters is within a range of 1.5%-0.4% of the mean transmission wavelength and the ray arriving at filter (7) has an angle of incidence between 10.degree.-60.degree., the measuring effected within this range being performed at more than two angles.

Abstract: A method of detecting for the presence of a combustible infrared absorbing gas in air, particularly in hazardous locations such as on gas and oil rigs. A source of switched infrared radiation is beamed onto a detector within a chamber and an output signal is derived as a measure of radiation incident on the detector. A reduction in the level of the output signal indicates absorption of radiation within the chamber and, thus, indication of the presence of infrared absorbing gas within the chamber. The output signal is processed in a manner which makes provision for the existence of changing levels of background radiation which would otherwise result in a false indication of the presence or absence of combustible gas.

Abstract: A radiation chopper has a chopper disk 9 which is driven by an electromotor 8 and disposed between a front and a rear part of the housing 2, 3 placed on top of each other wherein the rear part 3 of the housing has a multi-armed yoke 5 and the front part 2 of the housing has a support for at least one cell and at least one aperture 17, 18 permitting the radiation to pass from the chopper chamber 10 to the cell and at least one support 38, 39 disposed at the rear part 3 of the housing for mounting the radiation source. At each of its two ends, the motor 8 for driving the chopper disk 9 has one bearing collar 13, 15 of which the one in the rear can be inserted into a borehole 14 provided in the multi-armed yoke 5 which in turn is connected to supports 4, 4', . . . that are configured as one piece with the rear part 3 of the housing and the front bearing collar 15 engages a borehole 16 which is provided at the bottom of the supports 4, 4', . . . in the rear part 3 of the housing.

Abstract: A chopper, in an infrared imaging system, is used to scatter infrared radiation from a viewed scene. This scattered radiation is detected with an infrared detector and used to produce a reference signal, which represents the uniform average radiance of the scene. This reference signal may be substracted from a signal representing the unscattered radiation emitted by the scene, to produce a signal that represents only radiance differences and that is an optimal signal for amplification.

Abstract: Images of two fields of view of one or two scenes in a radiation sensor are generated by use of a single detector and common signal process circuitry. The two imaged fields of view, typically a narrow view and a wide view, are provided by two independent telescopes (18, 20), and are combined by use of a field-of-view switch (32) comprising a chopper wheel (34) or an optical switch in synchronized operation with a mirror scanner (22). The same field-of-view switch is employed in performing detector non-uniformity correction functions, such as automatic responsivity control and direct current restoration. Folding optics couples scanned radiation from the scanner to the switch. An additional field of view may be introduced by displacing a folding mirror of the folding optics. Also, a portion of a reflecting surface of the switch may be tilted to admit a reference beam of radiation useful in performing the functions of responsivity control and D.C. restoration.

Abstract: A pyrometer or other optical system has a silicon microstructure with a beam that is vibrated by optical radiation from an alternating source. The beam alternately blocks and passes radiation supplied to a photodiode from an optically emissive region. A sample and hold circuit receives the output of the photodiode and provides two simultaneous signals representative of the output of the photodiode when radiation is passed to the photodiode and blocked from the photodiode respectively. A processor measures the difference between the two signals and provides an output representative of the temperature of the optically emissive region.

Abstract: A liquid crystal chopper comprising a pair of electrically conductive substrates, a spacer keeping the substrates so as to define a space between the substrates, and a liquid crystal of DSM type which is enclosed in the space, with a dielectric anisotropy of -0.5 or more and not exceeding 0. An infrared sensor using the liquid crystal chopper in the above construction as a chopper mechanism to intermittently interrupt infrared rays incident upon the pyroelectric element. The infrared sensor has a short response time at the liquid crystal chopper and consumes less power.

Abstract: A multicomponent photometer comprises a light source (10) emitting a continuum and from which a measuring light beam (12) originates. The measuring light beam (12) passes through a sample vessel (14) in which a sample gas can be introduced. A plurality of first gas vessels (26), which are filled with different gases looked for in the sample gas, and one or several second gas vessels (28), each of which is associated with at least one of the first gas vessels (26) and contains a reference gas, are located in a first filter wheel (22) and are optionally movable into the path of rays of the measuring light beam (12). One or several filters (32), each of which transmits only a limited spectral region about an absorption band of a gas contained in a first gas vessel (26) (blocking filter), are located in a second filter wheel (24) through which one of the filters (32) is optionally movable into the path of rays of the measuring light beam. The measuring light beam (12 ) is applied to a detector (36).

Abstract: In a pyroelectric infrared detector, there is provided a member having a slit positioned in front of an array of pyroelectric elements, which interrupts an infrared image which is incident on the pyroelectric element array, and respective pyroelectric elements forming a row of the pyroelectric element array are wired so that they are connected in series electrically and adjacent pyroelectric element generate counter-electromotive forces. An infrared image irradiated on respective pyroelectric elements is scanned successively by the movement of the slit member along a row of the pyroelectric element array, thus obtaining information relating to an infrared intensity distribution from a heat source which emits IR rays which are being irradiated onto respective pyroelectric elements, from time series signals produced at both ends of the pyroelectric element array.

Abstract: A method and apparatus for accurate low noise demodulation of a modulated multi-signal input waveform. The multi-signal input waveform includes a plurality of sequential signal pulses, each pulse having a first adjacent background signal immediately preceding it and a second adjacent background signal immediately following it in time. The invention provides apparatus for synchronously separating the sequential signal pulses and apparatus for synchronously demodulating each sequential signal pulse. The separating apparatus separates each sequential signal pulse together with its adjacent background signals into one of a plurality of channels according to the sequence order of the pulse. Once the sequential signal pulses are separated into separate channels together with their background signals, the demodulating apparatus in each channel averages the first and second adjacent background signals for each pulse to yield an adjacent average background signal.

Abstract: The pyrometer includes at least one optical fibre (10) transparent to infra-red made of fluorite glass, a reference emitter (20) of infra-red flux, an infra-red detector (30) for receiving the infra-red flux emerging from the optical fibre (10) or the infra-red flux originating from the reference emitter (20), a mechanical modulator (40) for infra-red flux positioned, in the direction of flux propagation, upstream of the infra-red detector (30) for periodically and successively interrupting the infra-red fluxes emerging from the optical fibre (10) and originating from the reference emitter (20), an electronic means of demodulation (50) for receiving the output signal from the detector (30) and a servo-control signal emitted by the mechanical modulator (40) in order to ensure a synchronized measurement, and a measuring apparatus (60) connected to the electronic demodulation means (50) for indicating the temperature to be measured of the target irradiating the optical fiber.

Abstract: A circuit arrangement for providing a pulse modulated power feed to an infrared radiation source is disclosed. The radiation of the radiation source is detectable by a receiver and the circuit arrangement is improved such that the radiation source is as independent as possible from its radiation characteristics as well as from its thermal characteristics and can deliver a rapid and easily processable measuring signal to the receiver uninfluenced by ambient conditions. For this purpose, the power feed is controllable by means of a control unit during the pulse duration to an upper temperature desired value To and, during the no-pulse period, the power supply is controllable to a lower temperature desired value Tu with the alternation between the two desired values being triggered by a pulse generator connected to a desired value input of the control unit.

Abstract: The disclosure relates to a system for on-line normalization of the outputs of all of the detector elements of an infrared detector wherein, during the retrace period of the scanning mirror, infrared energy from a controlled thermoelectric source is reflected first from a high reflectivity sector of a rotating mirror and then from a relatively low reflectivity sector of the rotating mirror onto the detector. The detector output for the high and low reflectivity input signals is analyzed on a channel by channel basis by software controlled hardware and the gain of each channel is then adjusted in response thereto by the software controlled hardware individually. In this manner, each channel is caused to provide the same output for an identical input thereto.

Abstract: In a coated or uncoated film, variations in thickness as well as all possible casting errors may be dependably determined and evaluated, in that two light sources transmit modulated IR light wherein the modulation frequencies are different, wherein one light source transilluminates the film, while the other light source is arranged on the other side of the coating carrier, illuminates the latter obliquely and both the transilluminating and the reflected light bundles are conducted to a photo-receiver. The current signal arising in the photo-receiver is transformed into a current signal, amplified and feeds two electronic filters circuited in parallel, which free the signals from their modulation frequency, after which both signals are separately rectified. Subsequently the signal originating from the transmitted light portion is delogarithmized and forms a statement concerning the thickness of coating, while the light originating from the reflected portion evaluates surface errors.

Abstract: Apparatus for detecting the presence of an ink on a substrate comprises a number of LEDs (1) for irradiating the substrate (2) with radiation at at least two different wavelengths, at least one of the wavelengths being chosen to correspond to an absorption or relectance wavelength of the ink to be detected. A sequence generator (5) modulates the radiation at each wavelength in a respective, different manner. A radiation sensor (3) senses radiation emitted by the substrate (2). A correlator (7,8) correlates samples of the sensed radiation from the radiation sensor (3) with signals each of which is modulated by a respective one of the modulations applied to the radiation, to generate correlation signals. A monitor (9) monitors the correlation signals in order to detect the presence of the said ink.

Abstract: A system for measuring electromagnetic radiation originating from the hemhere corresponding to a solid angle of 2.pi. is provided wherein a highly sensitive low-inertia detector is disposed below a transmissive dome and wherein the chopped light detection method is utilized. There are provided above the transmissive dome two similarly or differently designed modulators which are in the shape of dome segments and which are fitted into each other. At least one of the modulators rotates about their common vertical axis or the modulators may both rotate about the common vertical axis, either at the same or a different speed in the same direction or in opposite directions.

Abstract: A catoptric type radiation thermometer having a catoptric type optical system is provided with a light receiving member for receiving an infrared ray emitted from an object to be measured. The infrared ray is periodically prevented and allowed to pass by a shutter blade fixed to an optical chopper supported by a bimorph cell vibrated by an AC signal. The optical chopper is arranged in such a manner that the longitudinal direction thereof is perpendicular to an optical axis of the optical system and the transverse direction is parallel to the axis and that one end of the chopper is supported at the outside of the passageway of the infrared ray.

Abstract: Two broad blackbody sources (24, 26) having a constantly maintained temperature differential therebetween are alternately directed via a chopper (40) onto a detector array (12) for testing same.

Abstract: A method and system for producing a temperature image of an object by the use of a television camera head responsive to temporal changes in infrared energy and operating in accordance with the pyroelectric effect. A chopper modulator alternately inhibits and facilitates transmission of thermal energy from a subject to the television camera head viewing the subject. Video information produced during separate first and second time intervals is separately stored. Video information produced during a third time interval between the first and second time intervals is not used. Video information produced during a fourth time interval subsequent to the second time interval is also not used. A signal is produced which is a function of the difference between the stored video information corresponding to the first and second time intervals. This difference signal is employed, in combination with appropriate synchronization signals, to drive a television monitor to produce a thermal image of the viewed subject.

Abstract: Apparatus for inserting and removing several filters from an optical path and for determining at all times the instantaneous positional relationship of each filter with respect to the optical path includes a set of filters mounted on a carrier which is attached to a resonant piezoelectric system, and further includes reference tracks also located on the carrier and extending in the direction of the oscillatory motion and including a sequence of binary indicia progressing in the direction of the oscillatory motion. The reference tracks are read optically to produce a series of binary electrical signals which are processed to yield the instantaneous position of the carrier and filters with respect to a fixed optical path.

Abstract: The disclosure is directed to a modulation device for a radiation detector device picking up an image field. The modulation device comprises a modulation disk disposed in the image field plane and having radial slits, said modulation disk executing a nutation about the axis of the image field. The modulation device further includes an optical system, a radiation-sensitive receiver arrangement and a signal processor. The radiation-sensitive receiver arrangement (11) comprises a grouping of radiation reception elements (E11 to Emm) forming a radiation receiver field (13), which elements are coupled with a window circuit (18, 22, 32) and are selectively addressable by the window circuit for the formation of at least one window zone within the radiation receiver field (13). The addressing occurs such that only signals of this at least one window zone are transmitted into the signal processor.

Abstract: An optical cell and detector assembly for a spectrophotometric analyzing apparatus which comprises a sample cell having walls of optically transparent material defining a sample cavity having closely adjacent the sample cavity a radiation detector and adjacent an opposite wall a lens whereby to focus radiation passing through the cell onto the detector. The apparatus may also comprise optical means for focussing the beam onto the sample cell, chopper means for periodically obscuring the beam, and filter means for selecting one or more wavelengths from the beam. The sample under test is an aqueous emulsion and the filters are chosen to determine the concentration of the non aqueous components of the emulsion by measuring the water displaced by the components.

Abstract: Correlation is used to enhance the temporal resolution capability of incident energy detectors for high bandwidth signals. Such enhanced resolution is attained by using a primary response of the detectors, which may be weak but which accurately replicates the temporal waveshape of the incident energy pulse. A secondary response of the detectors, which is delayed from and more powerful than the primary response, but does not track the incident energy pulse as well as the primary, is correlated with the primary response. The secondary response is preferably passed through an inverse matched filter to provide a pulse more faithfully following the incident energy pulse prior to correlation with the primary response. Circuitry is provided for performing the enhancement, and a modulating device is used to permit the detector to respond to long-duration incident energy.

Abstract: Device for synchronous modulation, synchronous light-path switch-over and control-signal derivation for step-drive controlled modulation and switch-over devices, especially for multibeam spectral analysis equipment and preferably for the infrared region of the spectrum, in which the radiation modulation is effected by a rotating light stop and the light path switch-over between a measuring beam and a reference beam is effected by pivoting mirrors. The device provides for the use of only a single photosensor. The synchronization between the stepping motor for moving the light stop and the stepping motors for moving the mirrors is effected via a counting logic and common clocking. Moreover, set pulses are generated to set the mirrors in defined positions, and control signals are generated for further processing.

Abstract: An apparatus for intermitting beams of light for use in a gas analyzer in which a rotary shaft of a chopper is supported by first and second ball bearings. An outside ring of the first ball bearing is fixedly mounted on a bearing housing and either an inside ring or an outside ring of the second ball bearing is adapted to be movable in the thrust or axial direction relative to the rotary shaft, whereby the second ball bearing is movably energized in the thrust direction by an elastic member to eliminate shake of the rotary shaft due to play in the ball bearings and thus reduce modulation noise to improve measuring accuracy of the gas analyzer.

Abstract: A spectrometric multigas analyzer is disclosed utilizing substantially isobaric temperature modulation of a gaseous sample in a highly reflective, random path, optical cavity or chamber. Multiple hot and cold ports on opposite sides of the chamber, and a gas recirculation circuit including a heating chamber, thermal regenerator, and cooling chamber, facilitate the alternate replacement of hot gas with cold gas and cold gas with hot gas in the optical chamber each cycle at a frequency of at least several Hertz, thereby producing, by gases of interest in the sample, a modulated spectral infrared emission and a modulated spectral radiant absorption of radiance from a radiant source shining into the optical chamber, which radiant source also provides heat for the heating chamber.

Abstract: Information regarding an object, especially brightness information, is obned by scanning the object with an optical scanner, especially an infrared scanner to provide a respective analog signal. The analog signal is produced by passing the received radiation past a chopper disk onto a detector through a secondary optical assembly. The output signal of the detector is digitized and supplied to a fast Fourier transformation processor which also receives a counting signal derived from the oscillation of the chopper disk. The system may be used, for example, for obtaining deviation and/or presence signals regarding the orientation of an earth satellite relative to the center of the earth.

Abstract: A metering light is projected onto an object to be photographed, and the reflection from the object with illumination of the metering light is analyzed to derive an electrical signal in accordance with which the focusing position of a photographic lens is adjusted. When the reflection is found to include a radiation resulting from foreign illumination which is harmonic with the pulsating frequency rate of the metering light, the output of the metering light source is modulated to a random pulsating form.

Abstract: A method and apparatus for determining the temperature of a hot body by a non-contact technique. It comprises a chopping disc 2 which may be disposed in the path of the radient heat energy from the object so providing a pulsed output of radient heat energy directed towards a pyroelectric element 7. Between the pyroelectric element 7 and the disc 2 is a further rotatable disc 4 having a pair of wavelength filters 6 and 6'. A microprocessor 14 operates to rotate the disc 4 to interpose each filter 6 and 6' in turn in the path of the pulsed output from the disc 2 at predetermined time intervals. The consequent output from the pyroelectric element 7 is, after amplification, rectification and smoothing in suitable circuits, fed to the microprocessor 14, which then calculates the ratio of the signal from the element 7 representative of power output through one of the filters, and the signal from element 7 representative of power output through the other filter.

Abstract: A method and an apparatus for processing the output signals of an optical rth-horizon sensor (1) operating in the infrared range of an orbiting, e.g. stationary earth satellite with respect to variously warm oppositely located earth rims (earth anomaly). With the earth-horizon sensor (1), an off-course signal is formed which is a measurement of the off-course angle of the line of sight of the earth-horizon sensor in relation to the satellite/earth central point connection line and is used for the attitude control of the earth satellite. This off-course signal is corrected in dependence on the earth anomaly.

Abstract: The invention is directed to a method for determining the anomaly portion the output signal of a zero-seeking earth-horizon sensor for a geostationary satellite. The horizon sensor comprises a chopper disk operated with constant frequency, which chopper disk pictures the image of oppositely located earth horizons on a common infrared detector. When the thermal radiation of the two earth horizons is different the anomaly portion contained in the detector output signal can be determined in that the off-course signals are measured for different amplitudes of the chopper disk. Since the anomaly-dependent portion in the detector output signal depends on this chopper amplitude, correcting amounts can be determined for the measured values corresponding to the anomaly portion.

Abstract: A method and apparatus for deriving an off-course signal for an orbiting th satellite, preferably a geostationary satellite, by an earth-horizon sensor. The earth-horizon sensor operates in the infrared range and comprises, in the focal plane of an input lens, a chopper disk, which is periodically reciprocated with a determined chopper frequency (f) and which has a diameter corresponding to the image of the earth, and a detector (1) receiving the periodically interrupted radiation of opposite earth rims. The output signal of the detector is demodulated synchronously with the chopper frequency (f) and corrected with a correction signal corresponding to different temperatures of opposite earth rims (earth anomaly).