Abstract: A multi-point non-invasive, real-time pyrometry-based temperature sensor (200) for simultaneously sensing semiconductor wafer (22) temperature and compensating for wafer emissivity effects. The pyrometer (200) measures the radiant energy that a heated semiconductor wafer (22) emits and coherent beams of light (224) that the semiconductor wafer (22) reflects. As a result, the sensor (200) generates accurate, high-resolution multi-point measurements of semiconductor wafer (22) temperature during a device fabrication process. The pyrometer (200) includes an infrared laser source (202) that directs coherent light beam (203) into beam splitter (204). From the beam splitter (204), the coherent light beam (203) is split into numerous incident coherent beams (210). Beams (210) travel via optical fiber bundles (218) to the surface of semiconductor wafer (22) within the fabrication reactor (80). Each optical fiber bundle (218) collects reflected coherent light beam and radiant energy from wafer (22).

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 wave length 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: The rotor exhaust gas bulk total temperature relative to the last blade row of a combustion turbine is determined by traversing an optical pyrometer radially across the last stage blades. The resulting radial temperature measurements are then flow weight averaged to provide an accurate bulk gas temperature relative to the last row of blades. Such temperature is useful in a feedback control system for the turbine. A technique of traversing is to cause the optical pyrometer to traverse by mounting its line of sight or optical axis at an angle to its axis of rotation.

Abstract: A gas turbine pyrometer filtering method and system uses a pyrometer to measure the high pressure turbine blade temperatures using infrared optical detection techniques. The pyrometer signal can be cluttered by positively biased noise. The turbine speed and the pyrometer electrical signal are alternately sampled by an analog to digital converter, and several revolutions of pyrometer data are stored in the local RAM. A data compression algorithm then selects single samples, at evenly spaced intervals, which results in a given number of revolutions, containing an exact number of data points of aligned data in RAM. This data is passed to a clutter rejection filter which then passes only the lowest value for each of the points in all revolutions of data. Thus, the revolutions of acquired data are reduced into a single revolution of filtered data for the current sampling. This single revolution of filtered data in then enter into a circular queue and the last element is discarded.

Abstract: Dual pyrometric detectors and method measure the temperature of a remote heated object in the presence of ambient radiation. One detector measures emitted radiation from both the remote object and from the environment, and the other detector measures radiation predominantly from the environment alone. The output signals from the two detectors are processed electronically to yield the detected radiation from the remote object alone. The result can then be electronically processed to display the pyrometrically-measured temperature of the remote object.

Abstract: An infrared temperature sensor with a sensor element sensitive for infrared radiation and which generates an analog output signal, permits a speed-variable and resolution-variable infrared temperature measurement, in that at least one resolution-adjustable converter means is provided for converting the analog signal into a digital signal and in that a digital signal processing means is provided for the program-controlled linearization and evaluation of the digital signal.

Abstract: Apparatus for optically determining the temperature of an object in an environment at elevated temperature provides enhanced measurement accuracy by sensing radiation from the object in two or more different wavebands of radiation. The information derived therefrom is cyclically sampled and processed to provide corrected emissivity of the object. The temperature of the object is accurately determined from the corrected emissivity and sensed radiation therefrom. The apparatus includes a radiation detector for receiving radiation during an interval, an optical filter structure with a plurality of optical filters of different radiation transmissive characteristics, and sampling circuits for receiving the radiation signal from the detector during a selected period within the interval during which radiation is supplied to the detector; wherein the selected period is shorter than the interval, is determined in response to the cyclic operation of the filter structure, and contains the least amlitude gradient.

Abstract: A multi-point non-invasive, real-time pyrometry-based temperature sensor (200) for simultaneously sensing semiconductor wafer (22) temperature and compensating for wafer emissivity effects. The pyrometer (200) measures the radiant energy that a heated semiconductor wafer (22) emits and coherent beams of light (224) that the semiconductor wafer (22) reflects. As a result, the sensor (200) generates accurate, high-resolution multi-point measurements of semiconductor wafer (22) temperature during a device fabrication process. The pyrometer (200) includes an infrared laser source (202) that directs coherent light beam (203) into beam splitter (204). From the beam splitter (204), the coherent light beam (203) is split into numerous incident coherent beams (210). Beams (210) travel via optical fiber bundles (218) to the surface of semiconductor wafer (22) within the fabrication reactor (80). Each optical fiber bundle (218) collects reflected coherent light beam and radiant energy from wafer (22).

Abstract: An infrared detector receives infrared energy from the target and provides a detector signal based primarily on the difference between the infrared detector temperature and the temperature of the reference temperature area of the detector. A contact temperature measurement device provides a reference signal which is a function of the temperature of the reference temperature area of the detector. A processor receives the detector and reference signals and combines the two signals in a non-linear manner to result in a signal which is representative of the temperature of the target. The method of non-linearly combining includes the use of gain and offset terms which may be altered to a limited extent by a technician in the field with a blackbody calibration source. As a result of the recalibration, accurate target temperature measurements are continually provided.

Abstract: The system and method for pyrometrically determining the temperature of a semiconductor wafer within a processing chamber accurately determines the actual emissivity of the semiconductor wafer at a reference temperature using multiple pyrometers operating at different wavelengths. The pyrometers are calibrated for radiation received from the processing chamber and their responses are then corrected to provide the proper temperature indication for a master wafer at a known reference temperature to yield emissivity of the master wafer. Other similar wafers exhibiting extreme values of emissivity are sensed at the reference temperature to provide pyrometer responses that are corrected in accordance with the master emissivity, and such corrected responses are used to establish a correlation between emissivities and the corrected pyrometer responses.

Abstract: This invention relates to a device for monitoring the temperature of the wheels of passing railroad cars. More particularly, this device includes a self-calibration function wherein a predetermined heat source is attached to the device, a fixed amplifier amplifies the resulting electric signal so as to generate a signal comparable in magnitude to that generated by a passing train, a variable gain amplifier further amplifies the signal, and the resulting signal is converted to a digital signal. The digital signal is used as a signal to the feedback input of a variable gain amplifier. In response to the digital signal, the variable gain amplifier adjusts its gain until the feedback signal reaches a predetermined value.

Abstract: Dual pyrometric detectors and method measure the temperature of a remote heated object in the presence of ambient radiation. One detector measures emitted radiation from both the remote object and from the environment, and the other direction measures radiation predominantly from the environment alone. The output signals from the two detectors are processed electronically to yield the detected radiation from the remote object alone. The result can then be electronically processed to display the pyrometrically-measured temperature of the remote object.

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: Method and apparatus for accurately and instantaneously determining the thermodynamic temperature of remote objects by continuous determination of the emissivity, the reflectivity, and optical constants, as well as the apparent or brightness temperature of the sample with a single instrument. The emissivity measurement is preferably made by a complex polarimeter including a laser that generates polarized light, which is reflected from the sample into a detector system. The detector system includes a beamsplitter, polarization analyzers, and four detectors to measure independently the four Stokes vectors of the reflected radiation. The same detectors, or a separate detector in the same instrument, is used to measure brightness temperature. Thus, the instrument is capable of measuring both the change in polarization upon reflection as well as the degree of depolarization and hence diffuseness.

Abstract: A radiation thermometer comprises a housing (1) within which is mounted a radiation detector system including a radiation sensor (2) positioned to receive radiation through a window (5) in the housing. The radiation detector system generates an electrical signal related to the sensed radiation. An optical signal generator (11, 14) is responsive to the electrical signal from the radiation detector system (9) and an internal housing temperature detector to generate a modulated optical signal whose frequency is related to the electrical signal from the radiation sensor and whose mark-space ratio is related to the signal from the internal temperature detector. The housing (1) is connectable with an optical waveguide, such as an optical fibre (16), into which the optical signal is coupled in use. A power source (13) is mounted within the housing (1) and is connected to the detector system (9).

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: 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: In order to measure the temperature of a body (3) extensively independently of interference radiation (.theta..sub.U1), a sensor (1) is provided wherein the radiation (.theta..sub.3) of the body (3) is chopped by means of a chopper (5) between the sensor (1) and the body (3). Since extraneous radiation originates predominantly from losses at the sensor (1) as well as from frictional heat of the chopper (5) in case a mechanical chopper (5) is provided, the housing temperature of the sensor (1) is detected for correction purposes on the side of the chopper (5) facing the sensor (1) by means of an additional sensor (13). Around and in the zone of the travel path of the mechanical chopper (5), by means of a third sensor (15), the ambient temperature of the chopper is detected, again for correction purposes.

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: Radiation detectors and method measure the emissivity of a remote, heated semiconductor wafer in the presence of ambient radiation. Incident radiation within a selected waveband from a controlled source intermittently radiates the remote wafer, and reflected radiation therefrom is detected in synchronism with the intermittent incident radiation to yield output indications of emissivity of the wafer under varying processing conditions. The temperature of the wafer is monitored by another radiation detector (or detectors) operating substantially within the same selected waveband, and the temperature indications thus derived are corrected in response to the output indications of emissivity to provide indications of the true temperature of the wafer.

Abstract: The infrared thermometer optical chopper includes a planar shutter having infrared radiation transmissive and infrared reflective portions arranged on the shutter, and a mechanism for rotating the shutter sequentially through a series of stop positions in which the transmissive and reflective portions are sequentially aligned with the internal optics of the infrared thermometer. A mechanism is also preferably provided for sensing the positioning of the shutter at the stop positions, to determine whether the shutter stop position alignment is in an infrared radiation transmissive phase or in an infrared radiation reflective phase.

Abstract: A method and apparatus for measuring a temperature of a body extensively independently of an interference radiation. The apparatus comprising a sensor wherein a radiation of the body is chopped or interrupted by a chopper disposed between the sensor and a body. In order to sense extraneous radiation which originates predominately from losses at the sensor as well as from frictional heat of the chopper, the housing temperature of the sensor is detected for correction purposes on a side of the chopper facing the sensor by an additional sensor. Around and in the zone of the travel path of the chopper, an additional sensor is provided for sensing an ambient temperature of the chopper.

Abstract: A method of determining true temperatures of a heated target material by its radiation based on prior knowledge of an emissivity function which describes the relationship between two spectral emissivities for the target material, comprising measuring two radiances corresponding to said two spectral emissivities from the target material, assuming a temperature of the target material, then calculating a pair of emissivities which satisfy the emissivity fuction whereat the assumed temperature is the true temperature of the target material.

Abstract: A thermal wave imaging apparatus generates a real time image of the surface and subsurface of an opaque solid object. A.C. electrical signals indicative of the configuration of the surface and subsurface of the object which are generated during a thermal wave scan of the object by a first heating beam which generates a localized temperature gradient on the object and a deflectable second probe beam heating beam, which deflection is detected by a detection device mounted adjacent to the object, are stored in an image memory under the control of a central processor. A refresh counter generates sequential, incremental signals used to control the X and Y axis deflection of a display monitor. Such signals also address the image memory and generate output data controlling the intensity of the display point at each generated X and Y axis deflection point.

Abstract: A high speed infrared temperature measuring device which consists of a lens barrel in an instrument housing, a sensor in the lens barrel to read an infrared target signal, a processing circuit for the signal, an automatic circuit for the thermoelectric cooler and a black body compensation circuit and means to read and record the processed signal.

Abstract: A temperature detection pyrometer for determining the temperature of a turbine blade detects radiation reflected and emitted from the turbine blade. The reflected radiation is a result of flame and hot carbon particles rather than the emission representing the blade temperature. The radiation is divided into two channels, each of which detects radiation in different, but preferrably overlapping wavelength bands, to detectors providing currents proportional to the radiation intensity in the respective channel. The signal from one channel is weighted with respect to the signal from the other by a constant that is equal to the ratio of the radiation in the two channels which is the attributable to the reflected radiation. The difference between the signals, after weighting the one signal by the constant provides an output that is a function of blade temperature only so the blade temperature may be obtained from a calibration curve or a look-up table.

Abstract: A two-dimensional bolometer array having electronic array uniformity correction. The individual resistive sensors in the bolometer array are not electrically uniform and uniformity is a requirement to permit efficient electrical readout of signals. An electronic correction circuit in this invention automatically corrects for non-uniformity in the array.

Abstract: A radiant-energy temperature measuring apparatus of a scanning type having a linear array of light-sensitive elements which generate photoelectric signals corresponding to respective amounts of radiant energy produced at different points of an object and vicinities thereof on a straight line corresponding to the above linear array, and further having a device for determining a temperature of the object at desired one of its different points, based on the photoelectric signal generated by one of the light-sensitive elements which optically matches the desired one point of the object. The apparatus includes an edge detector for detecting an edge of the object, based on the photoelectric signals generated by the light-sensitive elements, and a selector for selecting the desired one point of the object, by designating a number of the light-sensitive elements as counted from the element corresponding to the detected edge of the object, to the element which corresponds to the above-indicated desired one point.

Abstract: In an apparatus wherein an infrared sensor is incorporated opposite to an opening formed at a predetermined position of a housing, a distance keeping member for keeping a constant distance from a temperature measuring portion is further mounted on another predetermined position of the housing, and an output signal from the infrared sensor responding to the infrared rays from the temperature measuring portion is supplied to a temperature measuring circuit whose operational state is selected by a temperature measurement control switch, and the temperature of the temperature measuring portion is displayed on a display unit which is driven by the output signal from the temperature measuring circuit.

Abstract: A pyroelectric thermal sensor for measuring the surface temperature of an object on a non-contact basis using the signals produced by a pyroelectric element and a reference thermal sensor is operative to reduce the level of the output signal from the pyroelectric element proportionally by switching an interruptive time for interrupting a heat ray incident to the pyroelectric element when the output of an amplifier for amplifying the pyroelectric element signal approaches the state of saturation.

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: The temperature of a thermally emitting target which radiates over a band of wavelengths which includes first and second spaced wavelengths and which has an unknown emissivity characteristic at which the emissivity at one wavelength may but does not necessarily differ from the emissivity of another wavelength is read remotely by [a] deriving signals from those portions of the thermal radiation at these two wavelengths; [b] deriving signals from the reflected portions of two beams of radiation at these wavelengths which strike the target; and [c] by using these derived signals to compute the temperature.

Abstract: A pyrometer adapted to be disposed remotely from a heated diffusely reflecting target obtains a first electrical signal from that portion of target radiance which reaches the instrument. A laser beam is generated within the instrument and is directed upon the target, a portion of the beam being reflected back to the instrument. A second signal is obtain from this portion. The separation between target and instrument is measured and a third signal depending on the separation is produced. A fourth signal dependent upon the power level of the beam is produced. The instrument then computes from these signals the surface temperature of the target.

Abstract: A hand held radiation detector is adapted for scanning the subject while a bar graph at one end of the detector is observed. The field of view of the radiation detector is variable by means of removable lens assemblies which have Fresnel lenses positioned at the focal lengths of the lenses from the radiation sensor. The lens assemblies are matched to provide the same flux density to the radiation sensor independent of the field of view. Crosshairs provided on the rear of a lens support assist in aiming the radiation detector. The time constant of the display is varied with the sensitivity of the display.

Abstract: An apparatus for measuring bath temperature of metallurgical furnaces through a tuyere is disclosed. The apparatus comprises a periscope adapted to be inserted into a tuyere, a fiber optic cable having one end connected to the periscope for receiving radiation entering the tuyere from the bath of a furnace, and a two wavelength pyrometer connected to the other end of the fiber optic cable for analysing the radiations transmitted through the fiber optic cable to provide an indication of the temperature of the bath.

Abstract: The present invention relates to a procedure and a device for determination of the temperature of an object by measurement of electromagnetic radiation emitted by this object. A portion of the radiation emitted by the object of measurement is transmitted by a transmission device to a wavelength dividing device.The wavelength dividing device causes a portion of the spectrum of the radiation corresponding to the spectral sensitivity range of the detector or pair of detectors to be distributed across the radiation-sensitive surface of the detector or pair of detectors. The detector senses the position of the center of gravity of the illuminated spectrum which is converted by the signal processing unit to temperature information, and displayed by an output device.Using a sole position-sensitive detector, the relative magnitude of two currents I.sub.1 and I.sub.2 indicates the position of the center of gravity.

Abstract: A thermal wave imaging apparatus generates a real time image of the surface and subsurface of an opaque solid object. A.C. electrical signals indicative of the configuration of the surface and subsurface of the object which are generated during a thermal wave scan of the object by a first heating beam which generates a localized temperature gradient on the object and a deflectable second probe beam heating beam, which deflection is detected by a detection device mounted adjacent to the object, are stored in an image memory under the control of a central processor. A refresh counter generates sequential, incremental signals used to control the X and Y axis deflection of a display monitor. Such signals also address the image memory and generate output data controlling the intensity of the display point at each generated X and Y axis deflection point.

Abstract: An infrared sensor made of LiTaO.sub.3 is provided on a ceiling of a heating chamber of a microwave oven, and a chopper is provided so as to intermittently block infrared radiation emitted from food in the heating chamber. The infrared sensor is brought to face the food and the chopper alternately and provides a corresponding AC output signal. The temperature of the chopper is detected from the output signal of a separately provided chopper temperature sensor consisting of a thermister. The detected chopper temperature output signal is corrected in a microcomputer to be substantially in accord with chopper temperature components in the output signal of the infrared sensor. The corrected chopper temperature data is applied to the infrared sensor output data for removing the chopper temperature components from the output signal of the infrared sensor to obtain a food temperature signal corresponding to the sole temperature of the food.

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 pyrometer system for a gas-turbine engine, or the like, has a high-resolution radiation pyrometer that supplies signals to a detector unit. The detector unit includes an inverter that inverts the pyrometer output and supplies these signals via a diode to one electrode of a capacitor. The other electrode of the capacitor is grounded, a resistor being connected across the capacitor so that it is slowly discharged. The charge on the capacitor approximately follows the high-value/low-temperature signals, which are reinverted by a processing unit to give an averaged temperature indication. The diode is short-circuited for periods, approximately equal to the blade rotational frequency. During these periods the charge on the capacitor drops to the instantaneous value of the pyrometer output, producing a low-voltage/high-temperature spike. The detector unit includes a store to which these spikes are supplied after reinversion.

Abstract: A two-wire transducer-transmitter for non-contact temperature measurement provides, in a unitary housing, a radiation sensing device producing a signal in response to sensed infrared or visible radiation, and electronic circuitry for processing the signal to provide at a two-wire output a current linerarly proportional to the sensed target temperature, on the same two wires as input power preferably in the range of from 4 to 20 milliamperes D.C. full scale.

Abstract: A thermopile type detector which is constituted by an electrically insulating film, a thermopile supported on the film, a semiconductor substrate supporting the film, and a temperature sensing element on the surface of the substrate on which the film is supported and in the neighborhood of a cold junction of the thermopile. The temperature on the substrate immediately adjacent a cold junction of the thermopile can be measured for use in compensating the output of the thermopile for the changes in temperature of the cold junction. The temperature sensing element can be a semiconductor material such as a diode or a transistor forming a semiconductor with the substrate.

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: A method and apparatus to measure the temperature of a slab in a reheat furnace with increased accuracy using either a single or dual pyrometer system through use of a multiplicity of temperature correction functions involving temperatures of slab and wall, distance between a pyrometer and the slab at which it is aimed, a ratio of air and fuel supplying the furnace heat and radiation interferences. The functions are chosen by a microprocessor in the system dependent on temperature differentials, emissivity setting of the pyrometer, target distance between pyrometer and slab, and air and fuel flow rates existing and fluctuating in the system.

Abstract: A radiometer apparatus is described that is particularly useful for detecting clear air turbulence by sensing infrared radiation. The radiometer includes optics for directing infrared radiation past a chopper, lens and infrared filter assembly to a radiation sensor which produces an analog output signal that is routed through an N-path filter unit and then demodulated and integrated by an averaging integrator to produce temperature indicative differences for determination of the presence of clear air turbulence in the area then being examined by the apparatus, the N-path unit and averaging intergrator providing a high signal to noise ratio. An automatic calibration unit is also provided to provide stability and reliability to the apparatus.

Abstract: A microwave oven comprising a magnetron for emitting microwaves; a heating chamber body for holding food being heated by microwaves from the magnetron; an infrared ray transmitting section provided in the top wall of the heating chamber body for transmitting infrared rays emitted from the food; an infrared ray detecting device disposed over the infrared ray transmitting section and comprising a horn member and an infrared ray detecting element, the horn member being made of material capable of cutting off microwaves and having a hollow extending toward the heating chamber body into which infrared rays are applied from the food and the infrared ray detecting element being so positioned as to detect infrared rays condensed by the hollow, the hollow having a diameter increasing toward the heating chamber body and a minimum opening size smaller than the wavelength of microwaves and having a spread angle so set that only infrared rays emitted from the food may be allowed to reach the infrared ray detecting element

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.