Abstract: A multi-channel remote-temperature-sensing system has a reference temperature assembly for the reference junctions of a plurality of temperature sensors for determining temperatures at remote points. The assembly comprises an array of components each adapted to make thermal contact with a reference junction of a remote-temperature-sensing thermocouple, an absolute reference thermometer situated within the array for measuring an absolute reference temperature, a thermocouple for sensing a temperature difference between the absolute reference thermometer and a component of the array, and data processing means for calculating the temperature of the component of the array from the absolute reference temperature and the temperature difference.

Abstract: An optical fiber is installed to pass through a plurality of measurement places. Predetermined positions in the optical fiber are set at a predetermined temperature. When an optical signal is radiated on the optical fiber, Raman scattering occurs at various portions of the optical fiber. The intensities of the Raman scattered light components depend on temperatures. Backscattered light components of the Raman scattered light are sampled and stored in a memory. A temperature distribution on the optical fiber is obtained on the basis of the stored data. The temperatures of the mesurement places can be specified on the basis of the predetermined temperature on the obtained temperature distribution as a reference. The temperatures of the measurement places can be corrected on the basis of the predetermined temperature.

Abstract: A radiation clinical thermometer has a probe with an optical guide and an infrared sensor, a detection signal processing section, a body temperature operating section, and a display unit. A filter correction system for setting a correction value based on the transmission wavelength characteristics of a filter is also provided. The body temperature operating section receives infrared data, temperature-sensitive data, which takes into account the temperature equilibrium between the optical guide and the infrared sensor, and a correction value from the filter correction section so as to calculate body temperature data.

Abstract: An infrared thermometer has a field of view selected so that the temperature of the crop growing in a field is accurately measured. The infrared thermometer may be mounted on a support pole in a field to substantially continuously monitor the foliage temperature of the growing crop. In one preferred embodiment, the infrared thermometer comprises and instrument housing structure provided with an infrared telescope mounted on a turntable that scans through an angle of the field, while an electronic circuit simultaneously integrates the output of the infrared telescope. The angle to be scanned is selected by the user in accordance with his needs. In another embodiment, the infrared thermometer comprises a novel sensor head block including an aperture which provides a wide, elongated oval field of view for an infrared sensor provided therein. In both embodiments, the elongated oval field of view has a width that is at least four times its height.

Abstract: The present invention is an apparatus for calibrating a temperature feedback value in a water processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer.

Abstract: To remotely measure the unknown subsurface temperature T.sub.s of a bulk transparent medium such as ocean water, a laser beam having a high power or intensity is split into two parts, a probe beam and a reference beam. The probe beam is directed into a sample of ocean water, and the reference beam into a reference sample of water having a known temperature T.sub.r. The intensities of the two beams, which exceed a predetermined threshold are sufficient to cause stimulated Brillouin scattering (SBS) within the two samples and produce therefrom two phase-conjugate beams. The two phase-conjugate beams are mixed to produce a heterodyne frequency that is proportional to the difference in temperature T.sub.s and T.sub.r. The frequency difference is converted into a temperature value equal to the value of T.sub.s.

Abstract: An optical technique for determining surface temperature utilizes the Christiansen effect that is exhibited by dielectric materials; i.e., strong absorption bands at certain wavenumber values, causing the radiance of the material to be that which would characterize a theoretical black body at that wavenumber value.

Abstract: The present invention is a method and apparatus for calibrating a temperature feedback value in a wafer processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer.

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 radiation clinical thermometer includes a probe, a detection signal processing section, a body temperature operating section, and a display unit. A filter correction section for setting a correction value based on the transmission wavelength characteristics of a filter is arranged. The body temperature operating section receives infrared data, temperature-sensitive data, and the correction value from the filter correction section so as to calculate body temperature data.

Abstract: A temperature sensor is incorporated within a housing having a silicon window through which infra-red radiation can enter. Mounted on a support structure is a semiconductor fabrication consisting of a reference junction and a sensing junction, covered with a black absorber. The reference junction is responsive to the temperature of the housing, whereas the sensing junction is responsive to the temperature of the housing and also the temperature of a remote zone from which infra-red radiation can enter the housing via the window. A Peltier heater/cooler controls the temperature of the housing, which temperature is monitored by a sensor to provide a measure of that of the remote zone.

Abstract: A biomedical thermometer for taking the temperature of a person at various body sites, including the ear, includes a radiation detector, a temperature detector for measuring the temperature of the radiation detector, and a heating and cooling unit for changing the temperature of the radiation detector. The system also includes a temperature processor for generating an output proportional to the absolute temperature of the radiation detector, responsive to signals generated by the radiation detector and the temperature detector.

Abstract: A pavement inspection apparatus is described for inspecting the condition of a full lane of pavement using a vehicle capable of traveling along the lane at normal traffic speeds, such as 55 miles per hour. The apparatus is capable of determining the size and shapes of surface distress features such as longitudinal cracks, transverse cracks, alligator cracks, design joints, and potholes. The apparatus has two video array cameras that project downward onto the pavement with overlapping fields of view for generating X-Y pixel data from at least a 12-foot lane width of highway pavement as the vehicle moves over the pavement. The cameras are mounted at acute angles with respect to each other. The apparatus includes distress feature analysis electronics for determining the size, shape and location of surface distress features and evaluates such features against preset standard values to determine the severity of the determined features. Additionally, the apparatus has infrared cameras for subsurface exploration.

Abstract: A temperature measuring apparatus is provided for determining the temperature of a target material to be measured as compared with the temperature of a spaced reference source which has a temperature control for controlling the temperature of the reference source. A differential radiation detector having a first detector exposed to the target material and a second detector which is shielded from the target material and exposed to the reference source provides a differential output or error signal which is used to control the temperature of the reference source. When the reference source temperature is the same as the target, the temperature of the reference source is read out which is the temperature of the target material regardless of the emissivity. The differential radiation detector is positioned in spaced relation to the target material and is focused onto the target and the reference material and the error signal generated is used for controlling the temperature of the reference source.

Abstract: A pyrometric measurement method and a multi-channel pyrometer for determining the temperature T.sub.o of surfaces with different emissivities by measuring the spectral signal voltages U.sub.j at j=1 to n effective wavelengths. The invention obtains, by infrared measurements at at least two effective wavelengths, information concerning the object temperature and the emissivity relationships actually existing for selected surface materials, such as those which are typical for a user. The spectral signal voltages U.sub.ij are ascertained as a function of the difference U.sub.oj -U.sub.uj for a discrete number i=1 to n of surface materials differing in emissivity and the hypothetically possible spectral voltages U.sub.oij and, from these, the probable object temperature T.sub.o and the probable applicable surface material are determined from the measured spectral signal voltages U.sub.j, using the functional relationship that has been established for each emissivity .epsilon..sub.ij.

Abstract: A radiation detector has a dual element sensor. One sensor element detects thermal radiation of a target at the same time the second sensor element detects thermal radiation of a reference object adjacent to the target. The dual element sensor produces a signal of the difference in the sensed radiations. A remote meter displays the thermal difference and provides an indication of sensed mass of the target relative to the mass of the reference. The display is driven by a circuit which provides a fast response of the sensed thermal difference and a slow decay of the response to provide a somewhat continuous display between targets detected in a series. Alarms may be sounded in accordance with certain readings of the display. A continuously flowing, dynamic pattern of thermal differences is detected and displayed in applications of the detector to assembly line processes.

Abstract: A laser materials processing system for computing a real time cooling rate experienced on a workpiece and responsively controlling the operation of a materials processing laser. An image of a point of laser beam-material interaction is transmitted via imaging optical fibers to ratio pyrometer apparatus which provides temperature proportional signals. The temperature signals are used to compute cooling rate.

Abstract: A hand held probe unit has an infrared sensitive thermopile mounted in a metal housing kept at a constant reference temperature by a regulator circuit. A waveguide tube, surrounded by a thermally insulative probe, directs infrared emissions to the thermopile. The thermopile and regulator circuit of the probe unit are electrically connected to processing circuitry in a chopper unit. Prior to taking a patient's temperature, the probe unit is mated with the chopper unit so that the thermopile detects infrared emissions from a reference target which is also kept at a constant reference temperature by another regulator circuit. The processing circuitry repeatedly acquires the output level of the thermopile and stores calibration data. The probe unit is then removed from the chopper unit, the probe is covered with an IR transparent, disposable speculum, and is inserted in the patient's external ear canal.

Abstract: An optical temperature measurement technique that utilizes the decaying luminescent intensity characteristic of a sensor composed of a luminescent material that is excited to luminescence by a light pulse or other periodic or other intermittent source of radiation. The luminescent emissions of a preferred sensor exhibit an approximately exponential decay with time that is the average of a distribution of chemically reproducible crystallites and are repeatable with a high degree of accuracy regardless of excitation level or prior temperature history of the sensor.

Abstract: Infrared radiation emitted from tissue surface of body cavity is measured by an infrared sensor located within a probe which generates a signal voltage dependent on the difference in temperature between the tissue and the infrared sensor. An additional ambient sensor measures the ambient temperature of the infrared sensor. The signals of the two sensors are added. To calibrate and eliminate errors, the housing of the device is provided with a chamber shaped to receive the probe and containing a target viewed by the infrared sensor. An error signal is thus generated which is added to the signals of the two sensors when they view the body tissue. A disposable, sanitary cover for the probe is made of a truncated polyethylene member of substantially uniform thickness closed by an end window. A filter in the probe suppresses absorption bands of polyethylene to eliminate errors due to minor variations in cover thickness.

Abstract: In a double thermal coupled radiometer for preferable use with a centrifuge, an improved radiometer configuration is disclosed. The isothermal radiometic system improved is of the double junction variety (preferably copper-constantan-copper) and includes a black body housing defining a central concavity. The central concavity has a black body disk at the bottom thereof. The disk is preferably suspended by a copper and a constantan wire with one junction formed on the surface of the disk and the other junction formed on the surface of the housing. The improvement includes a plurality of and preferably three annular baffles defining central, circular and preferably concentric opening. These baffles are lodged in the opening of the housing above the mounted radiometer disk. The annular baffles on the side towards the radiation sources are coated as a black body so as to increase the thermal coupling of the black body housing to the ambient being radiometically observed.

Abstract: A portable temperature data recorder for temporarily storing plural sets of temperature data representative of temperatures at a single location or at different locations, and automatically transferring the stored temperature data to a data processing unit. The portable recorder has a connector for connection thereof to the data processing unit. The portable recorder may further have a connector for connection thereof to a stationary temperature detector or thermometer installed at each measurement location. Alternatively, the temperature recorder incorporate a temperature detector for measuring the temperatures at the measurement locations. A clock circuit may be provided in the portable recorder, so that the temperature data may be stored together with measurement time data. The temperature detector may be a radiation thermometer provided at the measurement location, or built in the portable recorder.

Abstract: A cooking apparatus determining a temperature of food to be cooked by detecting the changes in the intensity of the infrared rays from the food. The cooking apparatus includes an infrared ray detecting circuit having a detecting element which detects infrared rays from the food.When the actual temperature change in the vicinity of the detecting element is more than a predetermined value, the detecting element is prevented from receiving the infrared rays from the food. The detecting element detects the actual temperature, and the infrared ray detecting circuit outputs the corresponding detection value. The detection value from the infrared ray detecting circuit is stored in a control circuit. The output of the infrared ray detecting circuit is corrected by the stored detection value when the detecting element is exposed to the infrared rays from the food in order to carry out a precise temperature detection for the food.

Abstract: A device for the pyrometric measurement of the temperature of a graphite tube furnace for flameless atom absorption spectroscopy is described. According to the invention, a pyroelectric detector is used as radiation receptor. The radiation flux at high temperatures is limited by a cut-off filter which starts at about .lambda..gtoreq.1 .mu.m and which, at the same time, can be constructed as radiation collector lens. It preferably consists of germanium. The detector signal is amplified in preferably three amplification stages which are connected under microprocessor control in dependence on the preselectable temperature ranges of the graphite tube furnace. A temperature measuring range from room temperature to 3,000.degree. C. is achieved.

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 bolometer which is adapted for a wide-band of radiation including soft adiation, and in which the sensitivity of the time constant (the heat flow from the absorber layer to the dissipator layer) can be exactly preselected without regard to the wave length of the radiation. The bolometer includes an electrically insulating carrier foil which has mounted thereon an absorber layer on one side thereof and a resistance layer on the opposite side of the foil, the resistance layer being part of a resistance measuring bridge. A thermally conductive layer is placed between the absorber layer and the carrier foil. The thermally conductive layer has portions protruding beyond the absorber layer. A heat dissipator is in thermally conductive contact with the protruding portions of the thermally conductive layer to dissipate the heat of the absorber layer. The laterally protruding portions of the thermally conductive layer in contact with the heat dissipator are shielded against the radiation to be measured.

Abstract: Radiation measuring probe for contactless measurement of the surface temperature of an object, independent of the emissivity of the object. The probe includes a radiation receiver and a housing having interior surfaces defining an interior space. The radiation receiver is disposed in the interior space, thermally insulated with respect to the housing. The housing includes a shield which has a shield surface facing outwardly so as to be towards a surface of an object whose surface temperature is to be measured. The shield has an aperture opening into the shield surface, communicating with the interior space and through which thermal radiation emanating from the object impinges on the radiation receiver. The shield surface is blackened and configured to correspond to the contour of the surface of the object, and the interior surfaces of the housing are of low emissivity.

Abstract: An optical temperature measurement technique that utilizes the decaying luminescent intensity characteristic of a sensor composed of a luminescent material that is excited to luminescence by a light pulse or other periodic or other intermittent source of radiation. The luminescent emissions of a preferred sensor exhibit an approximately exponential decay with time that is the average of a distribution of chemically reproducible crystallites and are repeatable with a high degree of accuracy regardless of excitation level or prior temperature history of the sensor.

Abstract: A temperature measuring device for a metal caster comprises a radiation pyrometer including an IR diode for measuring the head radiation of the metal melt in the crucible of the metal caster. For this purpose, a graphite body dips into the metal melt. The graphite body is seated coaxially around one end of a hollow tube to whose other end is coupled a glass fiber cable which is connected with the IR evaluation diode. The graphite body which dips into the metal melt and simultaneously serves in a known manner as a closing plug for the crucible, now emits thermal radiation into the interior of the tube, such radiation substantially corresponding to the composition of the thermal radiation of a blackbody having the temperature of the metal melt. This thermal radiation is coupled into the glass fiber cable at the other end of the tube and fed to the IR diode for evaluation.

Abstract: Hand-held instrument for measuring the temperature of a target without contact with the target. The instrument utilizes a microprocessor and a digital display to calculate and indicate different temperature functions. Compensation is included for the effects of emissivity and ambient temperature changes which otherwise could result in inaccurate readings. Temperature trend direction liquid crystal arrow(s) actuated by the microprocessor are included in the display.

Abstract: The temperature of an object within a heating furnace is accurately measured, even in a contaminated atmosphere, by receiving microwaves within a specific 1 to 10 cm wavelength range by means of an antenna provided near the wall of the furnace facing the surface of the object to be measured. The temperature of the object is obtained by amplifying, and converting the relative intensity of the microwaves. The antenna is preferably in the form of a parabolic antenna having a heat insulating material applied to its front surface to maintain a constant temperature, and a circuit added to compensate for any sensitivity fluctuation due to temperature changes in the parabolic antenna.

Abstract: The invention teaches a method for measuring the temperature of remote hot samples in the presence of ambient radiation. A portion of the surface of the sample is treated to obtain a spectral emissivity different from the untreated surface. The spectral radiances of the treated and untreated surface portions are measured and the temperature calculated from these values and the known emissivities.

Abstract: Military mechanical field equipment, such as an electrical generator, is camouflaged from airborne IR detection by enclosing the equipment in a double-walled enclosure having hollow walls through which air is forced to flow. By adjusting the air flow in the enclosure, the radiance from the enclosure can be made the same as its immediate surroundings. A dual temperature sensor senses temperature differences between the enclosure surface and the surroundings and varies the air cooling accordingly until thermal balance is achieved.

Abstract: A hand held probe unit has an infrared sensitive thermopile mounted in a metal housing kept at a constant reference temperature by a regulator circuit. A waveguide tube, surrounded by a thermally insulative probe, directs infrared emissions to the thermopile. The thermopile and regulator circuit of the probe unit are electrically connected to processing circuitry in a chopper unit. Prior to taking a patient's temperature, the probe unit is mated with the chopper unit so that the thermopile detects infrared emissions from a reference target which is also kept at a constant reference temperature by another regulator circuit. The processing circuitry repeatedly acquires the output level of the thermopile and stores calibration data. The probe unit is then removed from the chopper unit, the probe is covered with an IR transparent, disposable speculum, and is inserted in the patient's external ear canal.

Abstract: A temperature measuring device suitable for high temperature measurements in the range of 500.degree.-2400.degree. C. utilizing a blackbody cavity to emit radiation in the wavelength band of 0.3 .mu.m-1.0 .mu.m. The emitted light is transmitted to a photodetector via a high temperature ceramic fiber which is transparent to the wavelength band radiated. The radiance of the cavity is utilized as a measure of its temperature.

Abstract: In the temperature measuring apparatus disposed herein, a first intermediate output signal is obtained which is a function of the ratio of the brightness of a target at two different wavelengths and a second intermediate output signal is generated which is a function of the brightness of the target at a single wavelength. The two intermediate output signals are combined in preselectable proportion to yield a temperature output signal which is relatively insensitive to target surface characteristics.

Abstract: A method for continuously measuring the surface temperature of a heated steel strip, includes providing a flat reflecting plate so as to face a heated steel strip at an angle of inclination (.alpha.) with the steel strip. A radiation thermometer measures the amount of heat radiation energy which is emitted from an arbitrary point on the surface of the steel strip and comes directly into the radiation thermometer; and the thermometer also measures the total sum of heat radiation energy which (a) is emitted from a different point on the surface of the steel strip and comes into the radiation thermometer after having been reflected at least twice between the steel strip and the reflecting plate and, (b) is emitted from a final reflecting point, on the steel strip, of the heat radiation from said different point.

Abstract: The characteristics of various solid materials, in particular, surfaces of and coatings on metals and thickness of surface hardening layers are measured without damaging the specimen. The phase angle of a continuous thermal surface wave produced by a modulated light beam is measured. The phase angle of the continuous thermal wave progressing along the surface of the specimen is measured by temperature detectors either at a fixed distance from the light spot, as a function of frequency, or at a fixed frequency, as a function of distance. The phase angle of the thermal wave depends upon the thickness of the surface hardened layer whereby such thickness is measured.

Abstract: The radiometric measurement of the temperature of remote targets is usually done with a radiometer having a detector whose field of view is alternately switched between the target and a reference temperature source. The detector output is then used to change the reference source temperature to equal the target temperature. According to the invention the reference source temperature is not changed by the measuring apparatus. The difference in detector signals obtained from the target and reference source is used to calculate the target temperature from the known laws of thermal radiation and the known detectivity and spectral response of the detector. The invention can be incorporated in thermal imaging apparatus using the radiation detector scanned to form the thermal image as the radiometer detector. In such radiometric thermal imaging apparatus an array of detectors is scanned across the scene in a raster and a corresponding visual raster is produced.

Abstract: A portable, battery operated noncontact temperature measuring device including a lens for collecting infrared radiation and a thermopile for producing a signal indicative of the intensity thereof. The thermopile signal is amplified, linearized and summed with an ambient temperature signal derived from a temperature responsive element, e.g. a diode chip mounted immediately adjacent a cold junction of the thermopile. The resulting composite temperature signal is then processed and displayed. The ambient temperature signal is also utilized to control the impedance of a dual field effect transistor, which in turn controls the gain of the amplifier. Thus, temperature induced variations in the responsivity of the thermopile are compensated by corresponding changes in the gain of the amplifier.

Abstract: The present invention is a system and method for remotely measuring the temperature of hot gases in fired furnaces. This is achieved by adjusting the physical temperature of a black body until it equals the radiation temperature of the black body as determined by a pyrometer viewing the black body through the hot gases.

Abstract: A thermometry system utilizes the thermally sensitive time dependent emission properties of luminescent materials. In one embodiment the system includes a probe constructed with an optic fiber bundle for conducting light both toward and away from the temperature sensitive luminescent element located at one end of the optic fiber bundle, a source for transient and/or modulated excitation of the temperature sensitive element, and a light responsive detection element located at the output end of the optic fiber bundle for detecting the transient and/or modulated light emissions by the luminescent temperature sensitive element. The emission signal received by the light responsive detector can be analyzed in a well defined manner to determine the temperature of the luminescent element and of any materials in thermal equilibrium with the luminescent material.

Abstract: Coke guide and coke oven infrared pyrometer degrading is minimized to continuously permit better accuracy and reliability in hostile environment of coke mass and heat, dust and/or dirt present in many coke plant areas. These benefits are obtained using production-worthy pyrometer equipment having a purged pyrometer with any of three window cleanliness monitors to determine errors and automatically correcting for same through self-calibration.

Abstract: A surface temperature measuring apparatus is arranged to comprise means for conducting a first radiant energy generated from an object to be measured, said energy conducting means being provided opposite to said object, and reference radiation source means provided to mask the influence of radiation noise from the furnace on a radiometer and to generate a second radiation whose level is substantially determinable, whereby the surface temperature of said object can be determined from the detected values of said first and second radiations.

Abstract: A thermal reference source which includes a blackbody element and which is capable of being either heated or cooled based on a measured temperature of a scene of interest of an infrared system.

Abstract: The present invention teaches a unique laser radiometer capable of accurately measuring the radiation temperature of a radiant surface and independently measuring the surface's emissivity. A narrow-band radiometer is combined with a laser reflectometer to measure concurrently radiance and emissivity of a remote, hot surface. Together, radiance and emissivity yield the true surface temperature of the remote target. A narrow receiver bandwidth is attained by one of two methods; (a) heterodyne detection or (b) optical filtering. A direct measurement of emissivity is used to adjust the value obtained for the thermal radiation signal to substantially enhance the accuracy of the temperature measurement for a given subject surface. The technique provides substantially high detection sensitivity over a very narrow spectral bandwidth.

Abstract: A photoluminescent indicator apparatus having automatic feedback means to maintain the sensitivity of the indicator apparatus with respect to variations in environmental conditions. The apparatus includes a sample of photoluminescent material having a photoluminescent decay rate which varies as a function of environmental conditions. The sample is positioned in a remote location having some unknown aspect of the environment desired to be measured. The sample is optically excited with a modulating signal to generate an excitation output signal functionally dependent on the modulating signal and indicative of the unknown environmental condition. A phase detection means is provided for comparing difference in phase between a phase reference signal and the excitation output signal to generate a phase differential signal functionally related to the photoluminescent decay rate of the sample.

Abstract: An individual gauge for measuring the thermal stresses to which a person is subjected has minature components which adapts the gauge to be supported on an individual. The gauge has two thermoelectric sensors such as thermocouples one of which is associated with a water-wet wick and the other is associated with a black surface exposed to the surrounding atmosphere. The sensors are connected through adding and integrating circuits for emitted signals to an electromagnetic memory for recording the signals.

Abstract: An infrared scanner for sensing temperature is presented with the inclusion of a meter providing a digital read-out of the temperature. The scanner utilizes an infrared detector, scanning a field including a reference of known temperature and an object of unknown temperature. The scan is performed by a raster controlled by a horizontal oscillator and a vertical sweep circuit. During the scan, video signals are emitted from a video amplifier, which signals correspond to the temperature of objects within the raster. Delay circuits are provided in interconnection between the video amplifier, horizontal oscillator, and vertical sweep circuit for isolating video signals corresponding to the temperature of the reference and the object. A logarithmic amplifier receives such video signals and produces an output indicative of the temperature of the object as a function of the temperature of the known reference.