JP2021139708A - Temperature measurement device, and temperature measurement method - Google Patents

Abstract

To simply prevent an output of an inaccurate temperature measurement value.SOLUTION: The present invention comprises: a light reception unit that receives thermal radiant light from a measurement object in a state where an absorber with wavelength dependency on spectral transmittance of a near-infrared ray band can exist on an optical path to the measurement object; a detection unit that detects spectral luminance of the thermal radiant light received by the light reception unit by two wavelengths in which spectral transmittance of the absorber is identical and the wavelength is mutually different, and generates first and second luminance signal data respectively: and a computation processing unit that has a temperature calculation unit calculating a temperature of the measurement object from a ratio of the first luminance signal data and the second luminance signal data. The computation processing unit comprises: a storage unit that stores a value of a threshold output signal serving as a value of the first or second luminance signal data corresponding to an allowable lower limit temperature in a measurement of a temperature of the measurement object; and a monitoring unit that, when at least any one of the first and second luminance signal data is equal to or less than the value of the threshold output signal, judges the temperature being not normally measured.SELECTED DRAWING: Figure 7

Description

The present invention relates to a temperature measuring device and a temperature measuring method.

The radiant temperature measurement method is a method of knowing the temperature of a target object by detecting the thermal radiant light emitted by the object according to the temperature with a measuring device such as a radiation thermometer. It is a measurable remote temperature measurement method. Today, many industries, including the steel industry, use such radiant temperature measurement methods.

In particular, in the steel industry, in the manufacturing process, it has a characteristic of absorbing thermal radiation in the near infrared band on the optical path between a measurement object such as a steel plate material and a measuring device such as a radiation thermometer. Absorbents such as water and fats are often present. In such a case, a part of the thermal radiant light from the object to be measured is absorbed by the absorber, which causes a measurement error and makes it impossible to measure the accurate temperature of the object to be measured.

Therefore, in order to suppress the measurement error caused by the absorber existing on the optical path as described above, the present inventors, for example, as disclosed in Patent Document 1 below, the spectroscopy of the absorber of interest. We have proposed a two-color radiation thermometer that uses two wavelengths with the same absorption coefficient as measurement wavelengths. In general, a two-color radiant thermometer observes thermal radiant light from an object to be measured at two different wavelengths, and the measurement principle is that the ratio of radiance at the two wavelengths changes according to the temperature. However, when an absorber is present on the optical path, there is a problem that the thermal radiant light is attenuated differently at the two wavelengths due to the absorber, which causes an error. Therefore, in the two-color radiant thermometer disclosed in Patent Document 1, the influence of the attenuation of the thermal radiant light is suppressed by selecting the wavelength so that the spectral absorption coefficients of the absorbers at the two wavelengths used for the measurement are the same. However, it is possible to measure the temperature accurately.

Japanese Unexamined Patent Publication No. 2019-23635

As a result of further verification using the two-color radiation thermometer disclosed in Patent Document 1, the present inventors have obtained a temperature measurement value that is output when the temperature of the object to be measured becomes too low. It was found that a hunting phenomenon occurs in which the temperature becomes unstable and vibrates. When such a hunting phenomenon occurs, it becomes difficult to properly evaluate the temperature of the object to be measured because it cannot be determined whether or not the output temperature measurement value is an accurate value.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is temperature measurement, which can more easily prevent an inaccurate temperature measurement value from being output. To provide equipment, temperature measurement methods and programs.

The temperature measuring device according to the present invention is a temperature measuring device that measures the temperature of an object to be measured by using two-color radiation temperature measurement. The first detection element determines the spectral emission brightness of the light receiving unit that receives the thermal radiation light from the measurement object and the thermal radiation light received by the light receiving unit in a state where it can exist on the optical path to the measurement object. To generate the first brightness signal data by detecting at the first wavelength using the The ratio of the first brightness signal data to the second brightness signal data and the detection unit that detects at a second wavelength having the same spectral transmittance as the first wavelength and generates the second brightness signal data. The first unit comprises an arithmetic processing unit having a temperature calculation unit for calculating the temperature of the measurement object, and the arithmetic processing unit corresponds to an allowable lower limit temperature in the measurement of the temperature of the measurement object. The threshold output is performed by at least one of the storage unit that stores the value of the threshold output signal which is the value of the 1-brightness signal data or the 2nd-brightness signal data, and the 1st-brightness signal data and the 2nd-brightness signal data. It is provided with a monitoring unit for determining that the temperature of the object to be measured is not normally measured when the value becomes equal to or less than the signal value.

In the temperature measuring method according to the present invention, in the temperature measuring method for measuring the temperature of an object to be measured by using two-color radiation temperature measurement, the absorber having a wavelength dependence on the spectral transmittance in the near infrared band is described above. The first detection element determines the light receiving step of receiving the thermal radiation light from the measurement object and the spectral emission brightness of the thermal radiation light received by the light receiving unit in a state where it can exist on the optical path to the measurement object. To generate the first brightness signal data by detecting at the first wavelength using the A detection step of detecting at a second wavelength having the same spectral transmittance as the first wavelength to generate second brightness signal data, and a ratio of the first brightness signal data to the second brightness signal data. A calculation processing step comprising a temperature calculation unit for calculating the temperature of the measurement object, and the calculation processing step corresponds to a lower limit temperature acceptable in the measurement of the temperature of the measurement object. The threshold output is performed by at least one of the storage step of storing the value of the threshold output signal which is the value of the 1-brightness signal data or the 2nd-brightness signal data, and the 1st-brightness signal data and the 2nd-brightness signal data. A monitoring step for determining that the temperature of the object to be measured is not normally measured when the value becomes equal to or less than the signal value is provided.

As described above, according to the present invention, it is possible to more easily prevent an inaccurate temperature measurement value from being output.

It is a graph for demonstrating the hunting phenomenon which occurs in a two-color radiation thermometer. It is a graph for demonstrating the hunting phenomenon which occurs in a two-color radiation thermometer. It is a graph for demonstrating the temperature measurement error caused by the variation of a photodetector. It is a graph which showed an example of the variation between the blackbody furnace temperature and the temperature measurement value of a two-color radiation thermometer. It is a graph which showed an example of the transition of the measurement lower limit temperature when the thermal radiant light is attenuated on an optical path. It is explanatory drawing which showed typically an example of the structure of the temperature measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing which showed typically an example of the structure of the temperature measuring apparatus which concerns on this embodiment. It is explanatory drawing which shows typically an example of the structure of the measuring part included in the temperature measuring device which concerns on this embodiment. It is a block diagram which shows typically an example of the structure of the arithmetic processing part included in the temperature measuring apparatus which concerns on this embodiment. It is explanatory drawing for demonstrating the method of specifying the threshold value output signal value in the temperature measuring apparatus which concerns on this embodiment. It is explanatory drawing for demonstrating the method of specifying the threshold value output signal value in the temperature measuring apparatus which concerns on this embodiment. It is explanatory drawing for demonstrating the function of the monitoring unit which the arithmetic processing unit which concerns on this embodiment has. It is a flow chart which showed an example of the flow of the temperature measuring method carried out by the temperature measuring apparatus which concerns on this embodiment. It is a block diagram which showed an example of the hardware composition of the arithmetic processing part which the temperature measuring apparatus which concerns on this embodiment has.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

(About the study conducted by the present inventors)
Prior to explaining the temperature measuring device and the temperature measuring method according to the embodiment of the present invention, see FIGS. 1A to 4 for further study contents using the two-color radiation thermometer disclosed in Patent Document 1. I will explain while.
1A and 1B are graphs for explaining a hunting phenomenon that occurs in a two-color radiation thermometer and causes the temperature measurement value to become unstable and vibrate. FIG. 2 is a graph for explaining the temperature measurement error caused by the variation of the photodetector. FIG. 3 is a graph showing an example of the variation between the blackbody furnace temperature and the temperature measurement value of the two-color radiation thermometer. FIG. 4 is a graph showing an example of the transition of the measurement lower limit temperature when the thermal radiant light is attenuated on the optical path.

The present inventors use the two-color radiation thermometer shown in Patent Document 1 and the conventional single-color radiation thermometer to intermittently apply water from the upper surface side to a steel material heated to 800 ° C. or higher. The state of temperature change when sprayed and intentionally cooled was measured. In the measurement, a thermocouple is provided on the lower surface side of the steel material to measure the lower surface temperature of the steel material, and a monochromatic radiation thermometer and a two-color radiation thermometer are provided on the upper surface side of the steel material to measure the upper surface temperature of the steel material. bottom. The two-color radiation thermometer used has two InGaAs elements, which are photodetectors of the DC detection type, as photodetectors, and the spectral transmittances of water in the vicinity of a wavelength of 1200 nm and a wavelength of 1300 nm are equal. It was set to measure at two wavelengths.

FIG. 1A is a graph showing the measurement results of the monochromatic radiation thermometer obtained by the measurement, and FIG. 1B is a graph showing the measurement results of the two-color radiation thermometer. In FIGS. 1A and 1B, the horizontal axis is the elapsed time (seconds) and the vertical axis is the temperature (° C.). In each of FIGS. 1A and 1B, the transition of the temperature of the lower surface of the steel material is also shown.

Comparing FIG. 1A and FIG. 1B, the temperature measurement results of the monochromatic radiation thermometer and the two-color radiation thermometer are monotonously decreased as the steel material bottom surface temperature as a whole, although there are fluctuations due to measurement errors. On the other hand, it can be seen that the temperature measurement error of the monochromatic radiation thermometer is larger than the temperature measurement error of the two-color radiation thermometer.

In such verification, the sprayed water remains on the surface of the steel material, and the sprayed water generates steam (here, steam including steam in which steam is aggregated is also referred to as steam). These water and steam Becomes an absorber of thermal radiation in the near-infrared band emitted from the surface of the steel material, and the state of existence of such an absorber changes from time to time. Therefore, in a monochromatic radiation thermometer, it is presumed that a large error is superimposed on the measured temperature due to the presence of such an absorber. On the other hand, the two-color radiation thermometer proposed by the present inventors measures the temperature while suppressing the influence of the absorber even when the above-mentioned heat radiation absorber is present on the optical path. Therefore, it is possible to suppress the temperature measurement error.

However, focusing on the temperature range of 500 ° C or less, the temperature measurement result of the monochromatic radiation thermometer shows that although the temperature measurement error is large, the overall temperature transition is consistent with the transition of the steel material bottom surface temperature, but two colors. From the temperature measurement result of the radiation thermometer, it can be seen that the temperature measurement result deviates significantly from the temperature of the lower surface of the steel material and is hunting. In particular, in the temperature range that should be about 450 ° C (the area surrounded by the broken line in FIG. 1B), the temperature measurement result of the two-color radiation thermometer has risen to around 600 ° C, and water is intermittently sprayed. Considering that it is intentionally cooled, it can be seen that the measurement result is abnormal.

The present inventors further investigated the cause of such a hunting phenomenon. As a result, in such a hunting phenomenon, the two-color ratio is calculated using the brightness values of the thermal radiation light at the two wavelengths, and the temperature of the object to be measured is specified based on the obtained two-color ratio. It turned out to be a phenomenon peculiar to the meter.

That is, as a photodetector for detecting light belonging to the near-infrared light band having a wavelength of about 1000 nm to 1700 nm, a DC detection type element (for example, an InGaAs element or a Si element) is often used. In such a DC detection type photodetector, when the amount of light incident on the photodetector becomes extremely small, the output of the signal from the photodetector becomes unstable and the output signal value varies. Became clear. In the two-color radiation thermometer proposed by the present inventors, as disclosed in Patent Document 1, the radiance value of the thermal radiance light by one light detector is converted into the heat by the other light detector. The two-color ratio obtained by dividing the radiance by the radiance value is used to calculate the temperature. Therefore, the radiance value located in the denominator of the above division (that is, the output signal value from the photodetector) becomes extremely small, and if there is a variation, a large variation occurs in the calculated two-color ratio, and as a result, The hunting phenomenon as shown in FIG. 1B occurs.

The present inventors observed a measurement target at 500 ° C. with a monochromatic radiation thermometer (detection wavelength: 1200 nm) and a two-color radiation thermometer (detection wavelength: 1200 nm, 1300 nm) using an InGaAs element as a photodetector. The degree of temperature measurement error caused by the variation in the output signal value of the photodetector was calculated based on the black body radiation theory. The obtained results are shown in FIG. In FIG. 2, the horizontal axis represents the magnitude (%) of the variation in the output signal value, and the vertical axis represents the temperature measurement error (° C.).

As is clear from FIG. 2, in the case of the monochromatic radiation thermometer, even if the variation of the output signal value is 8.0%, the temperature measurement error is 10 ° C. or less, whereas in the case of the two-color radiation thermometer. It can be seen that a temperature measurement error exceeding 10 ° C. occurs with a variation of only 1.0% in the output signal value. As described above, in the two-color radiation thermometer proposed by the present inventors, when the temperature of the object to be measured becomes significantly lower than the measurable temperature assumed by the photodetector, the output signal value varies. , It turned out that the temperature measurement error becomes remarkable.

Therefore, the present inventors observe the thermal radiation emitted from the blackbody furnace with a two-color radiation thermometer using a blackbody furnace whose temperature can be arbitrarily set, and according to the temperature of the blackbody furnace, We specifically verified how the temperature measurement values of the two-color radiation thermometer vary (the fluctuation range of the phenomenon that the measured values are not stable and fluctuate). The obtained results are shown in FIG. In FIG. 3, the horizontal axis represents the temperature (° C.) of the blackbody furnace, and the vertical axis represents the variation (° C.) in the temperature measurement value.

As is clear from FIG. 3, in the case of a two-color radiation thermometer using an InGaAs element as a photodetector, when the temperature of the blackbody furnace is 550 ° C or less, a variation of less than 5 ° C occurs, and the temperature of the blackbody furnace. It was found that when the temperature drops to 450 ° C, a variation of nearly 20 ° C occurs. Since such a variation in the temperature measurement value causes a temperature measurement error, it can be seen that when a two-color radiation thermometer using an InGaAs element is used, the lower limit temperature for measurement is determined according to the degree of the temperature measurement error to be obtained. For example, when it is desired to reduce the temperature measurement error to 10 ° C. or less, it can be seen that the lower limit of measurement of the two-color radiation thermometer using the InGaAs element is 500 ° C.

However, the lower limit temperature for measurement as illustrated in FIG. 3 is the lower limit temperature when the object to be measured is directly observed in a situation where the absorber does not exist on the optical path. Therefore, wavelength dependence on the spectral transmittance in the near-infrared band such as water, water vapor, fats and oils, solutions, glass, and resin on the optical path, as assumed by the two-color radiation thermometer proposed by the present inventors. In a measurement environment where there is an absorber with, the output signal value is unexpected even when the temperature of the object to be measured is higher than 500 ° C as a result of the attenuation of the thermal radiation light by the absorber. There will be variations.

FIG. 4 shows the results of calculation of how the lower limit of measurement temperature, which allows a temperature measurement error of 10 ° C., changes from 500 ° C. when an absorber is present on the optical path. In FIG. 4, the horizontal axis represents the transmittance of the absorber, and the vertical axis represents the lower limit temperature for measurement. As is clear from FIG. 4, it can be seen that the lower limit temperature for measurement increases as the transmittance decreases due to the absorber such as water, water vapor, oil, solution, glass, and resin.

From the verification results as described above, in the two-color radiation thermometer proposed by the present inventors, if the temperature indicated by the two-color radiation thermometer is simply used as the judgment criterion, the lower limit temperature for measurement should be accurately judged. It became clear that it could not be done. Based on this finding, as a result of diligent studies by the present inventors, it was found that the temperature indicated by the two-color radiation thermometer is not used as a criterion, but the output signal value itself from the optical detector is focused on. I came up with the temperature measuring device and the temperature measuring method according to the embodiment of the present invention as described above.

(About the configuration of the temperature measuring device)
Hereinafter, the overall configuration of the temperature measuring device 10 according to the embodiment of the present invention will be described first with reference to FIGS. 5A and 5B. 5A and 5B are explanatory views showing an example of the overall configuration of the temperature measuring device 10 according to the present embodiment.

In the temperature measuring device 10 according to the present embodiment, the heat radiant light in the near-infrared band emitted by the object to be measured has an absorber having a wavelength dependence on the spectral transmittance in the near-infrared band at least a part of the optical path. It is a device that detects in a possible state and measures the temperature of the object to be measured based on the detection result of the radiation brightness of thermal radiation. Here, examples of the absorber having a wavelength dependence on the spectral transmittance in the near infrared band include at least one of water, water vapor, fats and oils, solutions, glass and resin. Further, in the present embodiment, attention is paid particularly to the band of 940 nm to 1350 nm as the near infrared band. The reason why the lower limit is set to 940 nm is that water becomes a translucent body having a strong wavelength dependence in 800 nm or more (particularly 940 nm or more) belonging to the near infrared band. The reason why the upper limit is set to 1350 nm is that at 1350 nm or more, water becomes opaque when the water film thickness is 10 mm or more.

As shown in FIG. 5A, for example, the temperature measuring device 10 mainly includes a measuring unit 101, an arithmetic processing unit 103, and a storage unit 105.

The measuring unit 101 emits thermal radiant light (observation) with respect to a measurement object that emits thermal radiant light belonging to the near infrared band (for example, the band of 940 nm to 1350 nm), such as a steel plate in a high temperature state. The magnitude of light) is measured as the value of radiance. More specifically, the measuring unit 101 measures the thermal radiance of the object to be measured at two types of wavelengths at which the spectral transmittances of the absorbers are the same as each other, and emits the thermal radiance at these two types of wavelengths. Generate measurement data showing the detection result of brightness.

The measuring unit 101 corresponds to an optical system including various lenses / lens groups in a two-color radiation thermometer, sensors such as a photodetector, and the like. A more detailed configuration of the measuring unit 101 will be described later. Further, as disclosed in Patent Document 1, the two types of wavelengths measured by the measuring unit 101 are preset to two wavelengths having the same spectral transmittance.

When the measuring unit 101 measures the magnitude of the thermal radiation light of the object to be measured and generates measurement data showing the detection result of the radiance of the thermal radiation light, the generated measurement data is transmitted to the arithmetic processing unit 103 described later. Output.

The arithmetic processing unit 103 is realized by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a communication device, and the like. The arithmetic processing unit 103 controls the measurement processing performed by the measurement unit 101 in an integrated manner. Further, the arithmetic processing unit 103 performs arithmetic processing for calculating the temperature of the object to be measured based on the measurement data measured by the measurement unit 101. More specifically, the arithmetic processing unit 103 describes the relationship between the measurement data generated by the measurement unit 101 corresponding to the two types of wavelengths and the spectral radiance and temperature derived from Planck's blackbody radiation equation. The temperature of the object to be measured is calculated based on the formula. The information on the temperature of the measurement object calculated by the arithmetic processing unit 103 can be output as an image via a display screen or the like, as a printed matter via a printer or the like, or as data itself. ..

The detailed configuration of the arithmetic processing unit 103 will be described in detail later.

The storage unit 105 is realized, for example, by a RAM, a storage device, or the like included in the temperature measuring device 10 according to the present embodiment. The storage unit 105 contains various types such as the spectral transmittance of the absorber of interest, the spectral radiance of the object to be measured obtained by analyzing past operation data, and the weighting coefficient used for correcting the spectral transmittance. Parameters and data are stored. Further, in the storage unit 105, in addition to these data, various parameters that need to be stored when the temperature measuring device 10 according to the present embodiment needs to be stored when performing some processing, the progress of the processing, or the like, or Various databases, programs, etc. are recorded as appropriate. In the storage unit 105, the measurement unit 101, the arithmetic processing unit 103, and the like can freely perform data read / write processing.

Further, the storage unit 105 according to the present embodiment holds the value of the threshold output signal corresponding to the detection lower limit temperature with respect to the output signals output from each of the first detection element and the second detection element included in the measurement unit 101. ing. The value of the threshold output signal will be described later.

As schematically shown in FIG. 5A, the measuring unit 101, the arithmetic processing unit 103, and the storage unit 105 may be realized inside one measuring device as one function of, for example, a two-color radiation thermometer. Further, the measurement unit 101, the arithmetic processing unit 103, and the storage unit 105 may be distributed and mounted in a plurality of devices, for example, as shown in FIG. 5B. In the example shown in FIG. 5B, for example, the functions of the measuring unit 101 and the storage unit 105 are realized inside the measuring unit that functions as a two-color radiation thermometer, and calculations such as a personal computer, various servers, and various process computers are realized. The case where the functions of the arithmetic processing unit 103 and the storage unit 105 are realized inside the processing device is shown. In FIG. 5B, the storage unit 105 is realized as the storage units 105a and 105b in the measurement unit and the arithmetic processing unit, respectively, but the storage unit 105 may be realized only inside the measurement unit. It may be realized only inside the arithmetic processing unit.

<About the configuration example of the measuring unit>
Subsequently, a configuration example of the measurement unit 101 according to the present embodiment will be described in detail with reference to FIG. FIG. 6 is an explanatory diagram schematically showing an example of the configuration of the measuring unit included in the temperature measuring device according to the present embodiment.

The measuring unit 101 according to the present embodiment corresponds to the optical system in the two-color radiation thermometer, operates under the control of the arithmetic processing unit 103, and generates heat in the near-infrared band generated by the measurement object. Measure the radiant light. As schematically shown in FIG. 6, the measuring unit 101 includes a light receiving unit 111 that receives heat radiated light from the object to be measured, a detecting unit 113 that detects the heat radiated light received by the light receiving unit 111, and the detection unit 113. have.

In the measurement unit 101 according to the present embodiment, the light receiving unit 111 and the detection unit 113 as described above may be optically connected by various known light transmission mechanisms. As such an optical transmission mechanism, for example, various known optical fiber OFs can be mentioned. By connecting the light receiving unit 111 and the detection unit 113 by an optical transmission mechanism such as an optical fiber OF, the light receiving unit 111 can be arranged separately from the detection unit 113, according to the present embodiment. The convenience when using the temperature measuring device is further improved.

As shown in FIG. 6, the light receiving unit 111 connects the light receiving lens 121 that receives the heat radiated light from the measurement object and the heat radiated light from the measurement object that has passed through the light receiving lens 121 to the optical fiber OF. It has a connection coupler 123 and a connection coupler 123. The light receiving lens 121 and the connection coupler 123 function as a light guide optical system that guides thermal radiation light to the detection unit 113.

Here, the specific configuration of the light receiving unit 111 according to the present embodiment is not particularly limited. For example, in FIG. 6, one biconvex lens is shown as the light receiving lens 121, but the light receiving lens 121 may be a lens group composed of a plurality of optical elements. Further, the lens used for the light receiving lens 121 is not particularly limited, and known optical elements such as a spherical lens and an aspherical lens can be appropriately used. The connection coupler 123 and the optical fiber OF are not particularly limited, and various known connection couplers and optical fibers can be used.

The light receiving unit 111 receives the thermal radiation light of the object to be measured in a state where an absorber of various thicknesses (water in FIG. 6) may exist on the optical path to the object to be measured on at least a part of the surface. However, the heat radiant light from the measurement object in which the absorber is present becomes a substantially parallel luminous flux by the light receiving lens 121 of the light receiving unit 111 and reaches the connection coupler 123. The connection coupler 123 connects the heat radiant light guided from the light receiving lens 121 to one end of the optical fiber OF. The heat radiated light from the measurement object, which is received by the light receiving unit 111 and then transmitted by the optical fiber OF, is guided to the detection unit 113.

As illustrated in FIG. 6, the detection unit 113 includes a connection coupler 151 optically connected to the optical fiber OF, a beam splitter 153, optical filters 155a and 155b, condensing lenses 157a and 157b, and a sensor. It has 159a and 159b.

The thermal radiation light from the object to be measured through the connection coupler 151 is guided to the beam splitter 153, which is an example of the branching optical element. The luminous flux of the thermal radiation light reaching the beam splitter 153 is split into two optical paths by the beam splitter 153.

As shown in FIG. 6, an optical filter 155a, which is an example of the first optical filter, is provided on one optical path after branching, and the second optical filter is provided on the other optical path after branching. An optical filter 155b, which is an example, is provided.

The optical filters 155a and 155b are filters that function as wavelength selection filters, select the wavelength of the thermal radiation light, and transmit the thermal radiation light having a specific wavelength to the sensors 159a and 159b in the subsequent stage. As for the optical filters 155a and 155b, known ones can be used as long as they can transmit light of two preset wavelengths (observation wavelengths). Further, the optical filters 155a and 155b may be a narrow band wavelength selection filter or a general band wavelength selection filter (having a finite bandwidth). The center wavelength and the transmission band of the optical filters 155a and 155b are selected so that the transmittances of water are the same.

The thermal radiant light of one of the two observation wavelengths transmitted through the optical filter 155a is condensed by the condenser lens 157a to the sensor 159a which is an example of the first detection element. Further, the thermal radiant light of the other wavelength of the two observation wavelengths transmitted through the optical filter 155b is condensed by the condenser lens 157b to the sensor 159b which is an example of the second detection element.

The sensors 159a and 159b detect the spectral radiance of the thermal radiance from the measurement object guided by the condenser lenses 157a and 157b, respectively, and generate brightness signal data from the obtained spectral radiance. After that, each of the sensors 159a and 159b outputs the obtained luminance signal data to the arithmetic processing unit 103. Such a luminance signal corresponds to the measurement data showing the detection result of the radiance of the thermal radiant light. In the present embodiment, the measurement data output from the sensor 159a is referred to as the first measurement data (first brightness signal data) for convenience as an example of the first output signal, and the measurement data output from the sensor 159b. Is referred to as the second measurement data (second brightness signal data) for convenience as an example of the second output signal.

Here, the sensors 159a and 159b are not particularly limited, and known sensors can be used as long as they are suitable for the above two types of wavelengths for detecting thermal radiation light. Examples of such a sensor (photodetector) include various DC detection type sensors such as a detection element using Si and a detection element using InGaAs.

In FIG. 6, the condenser lenses 157a and 157b are schematically illustrated by using one biconvex lens, but these condenser lenses 157a and 157b are a lens group composed of a plurality of lenses. You may. Further, the lenses used for these condenser lenses 157a and 157b are not particularly limited, and known optical elements such as spherical lenses and aspherical lenses can be appropriately used.

Here, it is assumed that, for example, a wavelength in the vicinity of 1190 to 1200 nm is selected as one of the combination of the two observation wavelengths (that is, the transmission wavelength of each of the optical filters 155a and 155b). In this case, the other wavelength is selected from around 1300 nm.

The spectral transmittance at the wavelength selected from around 1300 nm is required to match the spectral transmittance at the wavelength selected from around 1190 to 1200 nm. If they do not match, the measurement principle disclosed in Patent Document 1 does not hold, and a temperature measurement error occurs as the degree of coincidence decreases.

As described above, a configuration example of the measurement unit 101 according to the present embodiment has been briefly described with reference to FIG.

<About the configuration example of the arithmetic processing unit 103>
Next, a configuration example of the arithmetic processing unit 103 according to the present embodiment will be described with reference to FIG. 7. FIG. 7 is a block diagram showing a configuration example of the arithmetic processing unit 103 according to the present embodiment.

As illustrated in FIG. 7, the arithmetic processing unit 103 according to the present embodiment includes a measurement control unit 171, a data acquisition unit 173, a temperature calculation unit 175, a monitoring unit 177, a result output unit 179, and display control. A unit 181 is mainly provided.

The measurement control unit 171 is realized by, for example, a CPU, a ROM, a RAM, an input device, an output device, a communication device, and the like. The measurement control unit 171 is a processing unit that comprehensively controls the functions of the temperature measurement device 10 according to the present embodiment. Further, the measurement control unit 171 controls the operation of the measurement unit 101 so as to measure the thermal radiation light from the measurement object at the two types of wavelengths as described above. Further, the measurement control unit 171 can output various set values such as measurement conditions for thermal radiation to the temperature calculation unit 175 and the monitoring unit 177, if necessary.

The data acquisition unit 173 is realized by, for example, a CPU, a ROM, a RAM, a communication device, or the like. The data acquisition unit 173 acquires the brightness signals (that is, the first measurement data and the second measurement data) at the two types of wavelengths generated by the measurement unit 101 and outputs them to the temperature calculation unit 175 and the monitoring unit 177, which will be described later. do. Further, the data acquisition unit 173 may associate the acquired luminance signals at the two types of wavelengths with time information related to the date and time when the luminance signal was acquired and store the luminance signals in the storage unit 105 as history information.

The temperature calculation unit 175 is realized by, for example, a CPU, a ROM, a RAM, or the like. The temperature calculation unit 175 uses the luminance signals (first measurement data and second measurement data) at the two types of wavelengths output from the data acquisition unit 173, and divides one luminance signal by the other luminance signal 2 The color ratio (in other words, the ratio of spectral radiance) is calculated. Further, the temperature calculation unit 175 calculates the temperature of the object to be measured by using the calculated two-color ratio and the relational expression between the two-color ratio and the temperature.

As disclosed in Patent Document 1, the two-color ratio R can be calculated by dividing one of the luminance signals at the two wavelengths by the other luminance signal. On the other hand, in the temperature measuring device 10 according to the present embodiment, as shown in the following equations (1) and (2), the absorption of thermal radiation light by the absorber is taken into consideration. Therefore, the two-color ratio R is expressed by the following formula (3) when the formula is derived in the same manner as in Patent Document 1 by using the following formulas (1) and (2).

Here, in the above equations (1) and (2), τ ₁ is the spectral transmittance of water at the wavelength λ _{1 , and τ 2} is the spectral transmittance of water at the wavelength λ _2. Further, the spectral transmittance τ of water is a function of the interfacial reflectance determined from the spectral absorption coefficient of water, the thickness of water, and the refractive indexes of both at the interface between water and air. At this time, if the interfacial reflection is omitted, the spectral transmittances τ ₁ and τ ₂ of _{water can be expressed as τ 1} = exp (−α ₁ × t) and τ ₂ = exp (−α ₂ × t), respectively. can. Here, α ₁ is the spectral absorption coefficient of water at the wavelength λ _{1 , α 2} is the spectral absorption coefficient of water at the wavelength λ ₂ , and t is the thickness of the water film.

As described above, in the measuring unit 101 according to the present embodiment, the spectral transmittance of the absorber (more accurately, since the detection wavelength has a bandwidth rather than a single wavelength, the effective transmittance in that wavelength band) is determined. Spectral radiance is measured at wavelengths that are identical to each other. Therefore, the terms related to absorption by the absorber shown in the first term on the middle side of the above formula (3) cancel each other out in the numerator and denominator, and the value becomes 1. _{Therefore, R λ} and Λ on the right side of the above equation (3) are as shown in the following equations (4a) and (4b).

_{Here, R λ} and Λ shown in the equations (4a) and (4b) are constants determined by the measurement conditions that can be acquired from the measuring unit 101. Therefore, the temperature calculation unit 175 can calculate the temperature T of the object to be measured by using the calculated two-color ratio R and the relational expression (leftmost side = rightmost side) in the above formula (3). It will be possible.

When the temperature calculation unit 175 calculates the two-color ratio R, it is particularly important to determine which of the two types of wavelengths λ ₁ and λ ₂ is the luminance signal as the denominator and which luminance signal is used as the molecule. It is not limited to this, and the reference luminance signal may not be changed during the arithmetic processing.

Further, the temperature calculation unit 175 may directly calculate the temperature by using the above formulas (1) and (2) without using the two-color ratio R represented by the above formula (3). That is, if the emissivity ε at the two types of wavelengths λ ₁ and λ ₂ is known, the unknowns in the above equations (1) and (2) are the temperature T and the thickness t of the water film. Therefore, the temperature calculation unit 175 can calculate the temperature T by simultaneously obtaining the solutions of the simultaneous equations by combining the above equations (1) and (2). Further, even if the emissivity ε at the two types of wavelengths λ ₁ and λ ₂ is unknown, if _{the emissivity ε at the wavelength λ 1} and the emissivity ε at the wavelength λ ₂ are equal to each other, the above equation is similarly obtained. It is possible to directly calculate the temperature T by combining (1) and equation (2). Here, the method of solving the simultaneous equations is not particularly limited. For example, if it can be solved analytically, it may be solved analytically, it may be solved by numerical calculation, or it may be solved as an optimum value problem. You may.

The temperature calculation unit 175 outputs the information regarding the temperature T of the measurement object calculated as described above to the result output unit 179, which will be described later.

The monitoring unit 177 is realized by, for example, a CPU, a ROM, a RAM, or the like. The monitoring unit 177 describes the first measurement data and the second measurement data, which are examples of the first output signal and the second output signal, and the threshold output signal stored in the storage unit 105, which are output from the data acquisition unit 173. Refer to the value and each, and monitor whether the temperature of the object to be measured is measured normally.

Here, as mentioned briefly above, the value of the threshold value output signal corresponds to the lower limit temperature of detection with respect to the output signals output from each of the first detection element and the second detection element included in the measuring unit 101. .. In the following, first, the threshold output signal value of interest in the present embodiment will be described in detail with reference to FIGS. 8 and 9. 8 and 9 are explanatory views for explaining a method of specifying a threshold output signal value in the temperature measuring device according to the present embodiment.

In order to specify the threshold output signal value, for example, as schematically shown in FIG. 8, a temperature measuring device 10 for which the threshold output signal value is to be specified and a blackbody furnace as a heat source are used. That is, the thermal radiant light radiated from the blackbody furnace having a known temperature is detected by the measuring unit 101 of the temperature measuring device 10 whose threshold output signal value is desired to be specified in a state where there is no absorber such as water on the optical path. .. After that, using the generated first measurement data and the second measurement data, the arithmetic processing unit 103 is made to calculate the temperature of the blackbody furnace according to the above method. Since the temperature of the blackbody furnace is known, the temperature measurement error at the blackbody furnace temperature of interest is specified by comparing the calculated blackbody furnace temperature with the actual blackbody furnace temperature. can do. Such a process is carried out while changing the temperature of the blackbody furnace, and the obtained temperature measurement error matches the maximum temperature measurement error that can be tolerated in order to ensure the measurement accuracy of the temperature measuring device 10. , Identify the temperature of the blackbody furnace. The temperature thus obtained is the measurement lower limit temperature _TL of the temperature measuring device 10 of interest.

Here, the first measurement data and the second measurement data obtained at the time of the lower limit measurement temperature _TL are referred to as _{S 1L} and S _{2L, respectively.} These two types of output signal values S _1L and S _2L are threshold output signals corresponding to the allowable lower limit temperature in the measurement of the temperature of the object to be measured (to ensure an acceptable measurement error). Candidate for value. That is, assuming that the threshold output signal value _{is expressed as S Th} , the threshold output signal value S _Th has a smaller output signal value than _{S 1L} and S _2L , as schematically shown in FIG. Become. In other words, the threshold output signal value S _{Th is S Th} = min (S _1L , S 1L, using the function min (a, b) that compares the magnitude of the two input values and outputs a smaller value. It can be expressed as S _2L).

The storage unit 105 according to the present embodiment holds in advance data related _{to the threshold output signal value STh specified as described above.}

In the monitoring unit 177 according to the present embodiment, in parallel with the temperature calculation process by the temperature calculation unit 175 as described above, the threshold output signal value _ST and two types of outputs output from the data acquisition unit 173 are output. the signal value S _1, S _2, on the basis of whether the temperature of the measurement object is measured normally being monitored. That is, as schematically shown in FIG. 10, the monitoring unit 177 has a threshold output signal value S _{Th stored in the storage unit 105 and two types of output signal values S 1} output from the data acquisition unit 173. , S ₂ and the magnitude comparison are carried out at any time. _{At this time, in the monitoring unit 177, at least one} of the two types of output signal values S 1 and S ₂ is equal to or less than the threshold output signal value S _Th , regardless of the temperature of the object to be measured calculated by the temperature calculation unit 175. If, it is determined that the temperature of the object to be measured is not measured normally.

In this way, the monitoring unit 177 uses the output signal values S1 and S2, which are the original data for calculating the two-color ratio R, to measure the temperature of the object to be measured regardless of the calculated temperature of the object to be measured. To determine if is being measured normally. Therefore, even if the actual temperature of the object to be measured is near the lower limit of measurement temperature and the hunting phenomenon as shown in FIG. 1B occurs, the monitoring unit 177 is not confused by the calculated temperature. It is possible to accurately determine whether or not normal measurement is being performed.

The monitoring unit 177 outputs the information regarding the determination result obtained in this way to the result output unit 179.

The result output unit 179 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, or the like. The result output unit 179 outputs the information regarding the temperature T of the measurement object output from the temperature calculation unit 175 to the user of the temperature measurement device 10 while referring to the information regarding the determination result output from the monitoring unit 177. More specifically, when the monitoring unit 177 outputs information that the measurement is normally performed, the result output unit 179 outputs the temperature T of the measurement object output from the temperature calculation unit 175. Information about the above is output to the user of the temperature measuring device 10. Further, when the monitoring unit 177 outputs information that the measurement is not normally performed, the result output unit 179 may use the information regarding the temperature T of the measurement object output from the temperature calculation unit 175. The result indicating that measurement is not possible is output to the user of the temperature measuring device 10.

Specifically, the result output unit 179 associates the data corresponding to the temperature measurement result or the data indicating that the measurement is impossible with the time data related to the date and time when the data was generated, and controls various servers and controls. It can be output to a device or output as a paper medium using an output device such as a printer. Further, the result output unit 179 may output data corresponding to the temperature measurement result or data indicating that the measurement is impossible to various information processing devices such as a computer provided externally, or various types. It may be output to the recording medium of.

Further, the result output unit 179 outputs data corresponding to the temperature measurement result or data indicating that the measurement is impossible to an output device such as a display provided in the temperature measuring device 10 or various devices provided externally. When outputting to the display or the like possessed by the above, the determination result is output in cooperation with the display control unit 181 described later.

The display control unit 181 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, or the like. The display control unit 181 performs display control when displaying data corresponding to the temperature measurement result or data indicating that measurement is not possible on various display devices such as a display. As a result, the user of the temperature measuring device 10 can grasp the measurement result regarding the temperature of the object to be measured or the judgment result that the measurement is impossible on the spot.

The above is an example of the function of the arithmetic processing unit 103 according to the present embodiment. Each of the above components may be configured by using general-purpose members or circuits, or may be configured by hardware specialized for the function of each component. Further, the CPU or the like may perform all the functions of each component. Therefore, it is possible to appropriately change the configuration to be used according to the technical level at each time when the present embodiment is implemented.

It is possible to create a computer program for realizing each function of the arithmetic processing unit according to the present embodiment as described above and implement it on a personal computer or the like. It is also possible to provide a computer-readable recording medium in which such a computer program is stored. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, a flash memory, or the like. Further, the above computer program may be distributed via a network, for example, without using a recording medium.

As described above, the configuration of the temperature measuring device 10 according to the present embodiment has been described in detail with reference to FIGS. 5A to 10.

(About temperature measurement method)
Subsequently, with reference to FIG. 11, an example of the flow of the temperature measuring method implemented by the temperature measuring device 10 according to the present embodiment will be briefly described. FIG. 11 is a flow chart showing an example of the flow of the temperature measuring method according to the present embodiment.

In the temperature measuring device 10 according to the present embodiment, first, under the control of the measurement control unit 171 of the arithmetic processing unit 103, the measurement unit 101 heats from the object to be measured at two wavelengths having the same spectral transmittance. The emitted light is measured (step S101). The measurement unit 101 outputs the measurement data of the thermal radiation light at two wavelengths to the arithmetic processing unit 103 as the first measurement data and the second measurement data.

The data acquisition unit 173 of the arithmetic processing unit 103 outputs the first measurement data and the second measurement data output from the measurement unit 101 to the temperature calculation unit 175 and the monitoring unit 177.

Temperature calculating unit 175, first, by using the luminance signal _S 1, _{S 2} of the first measurement data and the second measurement 2 wavelengths respectively obtained from the data, calculates the dichroic ratio R (step S103). Subsequently, the temperature calculation unit 175 outputs the temperature of the object to be measured based on the relational expression showing the relationship between the two-color ratio and the temperature and the calculated two-color ratio R (step S105). After that, the temperature calculation unit 175 outputs the information regarding the temperature of the obtained measurement object to the result output unit 179.

On the other hand, in parallel with the temperature calculating process by the temperature calculation unit 175, the monitoring unit 177 uses the luminance signal S _1, S ₂ at two wavelengths, to implement magnitude determination between the threshold output signal values S _Th ( Step S107). More specifically, the monitoring unit 177 determines whether or not the relationship of S _Th ≤ min (S ₁ , S _{2 ) is established for the two types of luminance signals S 1} and S _{2 of interest (step S109).} ..

When _{the relationship of S Th} ≤ min (S ₁ , S ₂ ) is not established (step S109-NO), the monitoring unit 111 outputs a result indicating that the measurement is normal to the result output unit 179 (step S111). ). On the other hand, _{when the relationship of S Th} ≤ min (S ₁ , S ₂ ) is established (step S109-YES), the monitoring unit 111 outputs a result indicating that measurement is impossible to the result output unit 179 (step S113).

The result output unit 179 outputs the measurement result based on the information on the temperature of the measurement object obtained from the temperature calculation unit 175 and the information on the determination result output from the monitoring unit 177 (step S115). Specifically, the result output unit 179 outputs information on the temperature of the measurement object calculated by the temperature calculation unit 175 when the monitoring unit 177 outputs a result indicating that the measurement is normal. .. On the other hand, when the monitoring unit 177 outputs a result indicating that the measurement is impossible, the result output unit 179 is not the information regarding the temperature of the measurement object calculated by the temperature calculation unit 175, and indicates that the measurement is impossible. The result showing is output.

As a result, in the temperature measurement method according to the present embodiment, it is possible to more easily prevent the output of an inaccurate temperature measurement value.

As described above, an example of the flow of the temperature measuring method according to the present embodiment has been briefly described with reference to FIG.

(About hardware configuration)
Next, with reference to FIG. 12, the hardware configuration of the arithmetic processing unit 103 included in the temperature measuring device 10 according to the present embodiment will be described in detail. FIG. 12 is a block diagram for explaining the hardware configuration of the arithmetic processing unit 103 according to the present embodiment.

The arithmetic processing unit 103 mainly includes a CPU 901, a ROM 903, and a RAM 905. Further, the arithmetic processing unit 103 further includes a bus 907, an input device 909, an output device 911, a storage device 913, a drive 915, a connection port 917, and a communication device 919.

The CPU 901 functions as a central processing device and a control device, and controls all or a part of the operation in the arithmetic processing unit 103 according to various programs recorded in the ROM 903, the RAM 905, the storage device 913, or the removable recording medium 921. do. The ROM 903 stores programs, calculation parameters, and the like used by the CPU 901. The RAM 905 primarily stores the program used by the CPU 901, parameters that change as appropriate in the execution of the program, and the like. These are connected to each other by a bus 907 composed of an internal bus such as a CPU bus.

The bus 907 is connected to an external bus such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge.

The input device 909 is an operating means operated by the user, such as a mouse, a keyboard, a touch panel, buttons, switches, and levers. Further, the input device 909 may be, for example, a remote control means (so-called remote controller) using infrared rays or other radio waves, or an externally connected device 923 such as a PDA corresponding to the operation of the temperature measuring device 10. You may. Further, the input device 909 is composed of, for example, an input control circuit that generates an input signal based on the information input by the user using the above-mentioned operating means and outputs the input signal to the CPU 901. By operating the input device 909, the user can input various data to the temperature measuring device 10 and instruct the processing operation.

The output device 911 is composed of a device capable of visually or audibly notifying the user of the acquired information. Such devices include display devices such as CRT display devices, liquid crystal display devices, plasma display devices, EL display devices and lamps, audio output devices such as speakers and headphones, printer devices, mobile phones, facsimiles and the like. The output device 911 outputs, for example, the results obtained by various processes performed by the arithmetic processing unit 103. Specifically, the display device displays the results obtained by various processes performed by the arithmetic processing unit 103 as text or an image. On the other hand, the audio output device converts an audio signal composed of reproduced audio data, acoustic data, and the like into an analog signal and outputs the signal.

The storage device 913 is a data storage device configured as an example of the storage unit of the arithmetic processing unit 103. The storage device 913 is composed of, for example, a magnetic storage device such as an HDD (Hard Disk Drive), a semiconductor storage device, an optical storage device, an optical magnetic storage device, or the like. The storage device 913 stores programs executed by the CPU 901, various data, various data acquired from the outside, and the like.

The drive 915 is a reader / writer for a recording medium, and is built in or externally attached to the arithmetic processing unit 103. The drive 915 reads the information recorded on the removable recording medium 921 such as the mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, and outputs the information to the RAM 905. The drive 915 can also write a record to a removable recording medium 921 such as a mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory. The removable recording medium 921 is, for example, a CD media, a DVD media, a Blu-ray (registered trademark) media, or the like. Further, the removable recording medium 921 may be a compact flash (registered trademark) (CompactFlash: CF), a flash memory, an SD memory card (Secure Digital memory card), or the like. Further, the removable recording medium 921 may be, for example, an IC card (Integrated Circuit card) or an electronic device on which a non-contact type IC chip is mounted.

The connection port 917 is a port for directly connecting the device to the arithmetic processing unit 103. As an example of the connection port 917, there are a USB (Universal Serial Bus) port, an IEEE1394 port, a SCSI (Small Computer System Interface) port, an RS-232C port, an HDMI (registered trademark) (High-Definition Multisystem) port, etc. By connecting the externally connected device 923 to the connection port 917, the arithmetic processing unit 103 directly acquires various data from the externally connected device 923 and provides various data to the externally connected device 923.

The communication device 919 is, for example, a communication interface composed of a communication device or the like for connecting to the communication network 925. The communication device 919 is, for example, a communication card for a wired or wireless LAN (Local Area Network), Bluetooth (registered trademark), WUSB (Wireless USB), or the like. Further, the communication device 919 may be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), a modem for various communications, or the like. The communication device 919 can transmit and receive signals and the like to and from the Internet and other communication devices in accordance with a predetermined protocol such as TCP / IP. Further, the communication network 925 connected to the communication device 919 is composed of a network connected by wire or wireless, and is, for example, the Internet, a home LAN, an in-house LAN, an infrared communication, a radio wave communication, a satellite communication, or the like. You may.

The above is an example of a hardware configuration capable of realizing the function of the arithmetic processing unit 103 according to the embodiment of the present invention. Each of the above-mentioned components may be configured by using general-purpose members, or may be configured by hardware specialized for the function of each component. Therefore, it is possible to appropriately change the hardware configuration to be used according to the technical level at each time when the present embodiment is implemented.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

10 Temperature measuring device 101 Measuring unit 103 Calculation processing unit 105 Storage unit 111 Light receiving unit 113 Detection unit 121 Light receiving lens 123, 151 Connection coupler 153 Beam splitter 155a, 155b Optical filter 157a, 157b Condensing lens 159a, 159b Sensor 171 Measurement control unit 173 Data acquisition unit 175 Temperature calculation unit 177 Monitoring unit 179 Result output unit 181 Display control unit

Claims (4)

In a temperature measuring device that measures the temperature of an object to be measured using two-color radiation temperature measurement
An absorber that receives wavelength-dependent spectral transmittance in the near-infrared band, and a light receiving unit that receives thermal radiant light from the measurement object in a state where it can exist on the optical path to the measurement object.
The spectral radiance of the thermal radiance received by the light receiving unit is detected at the first wavelength by using the first detection element to generate the first brightness signal data, and the spectral radiance is measured by the second detection element. Is used to detect at a second wavelength different from the first wavelength and the spectral transmittance of the absorber is the same as the first wavelength to generate second radiance signal data. With the detector
An arithmetic processing unit having a temperature calculation unit that calculates the temperature of the object to be measured from the ratio of the first luminance signal data and the second luminance signal data.
With
The arithmetic processing unit
A storage unit that stores the value of the threshold output signal, which is the value of the first brightness signal data or the second brightness signal data, corresponding to the lower limit temperature that can be tolerated in the measurement of the temperature of the measurement object.
When at least one of the first luminance signal data and the second luminance signal data is equal to or less than the value of the threshold output signal, monitoring for determining that the temperature of the object to be measured is not normally measured. Department and
A temperature measuring device equipped with. Using the temperature measuring device, the temperature of the heat source is calculated in advance while changing the temperature of the heat source having a known temperature, and the maximum allowable accuracy is obtained from the known temperature and the calculated temperature of the heat source. Specify the temperature at which the temperature measurement error and the temperature measurement error calculated by the temperature measuring device match.
Among the first luminance signal data and the second luminance signal data, the smaller value of the first luminance signal data and the second luminance data at the specified temperature is set as the value of the threshold output signal. The temperature measuring device according to claim 1. The temperature measuring device according to claim 1 or 2, wherein the absorber is at least one of water, fat, solution, glass, and resin. In a temperature measurement method for measuring the temperature of an object to be measured using two-color radiation temperature measurement,
A light receiving step that receives thermal radiant light from the measurement object in a state where an absorber having a wavelength dependence on the spectral transmittance in the near infrared band can exist on the optical path to the measurement object.
The spectral radiance of the thermal radiance received by the light receiving unit is detected at the first wavelength by using the first detection element to generate the first brightness signal data, and the spectral radiance is measured by the second detection element. Is used to detect at a second wavelength different from the first wavelength and the spectral transmittance of the absorber is the same as the first wavelength to generate second radiance signal data. Detection step and
An arithmetic processing step having a temperature calculation unit for calculating the temperature of the object to be measured from the ratio of the first luminance signal data and the second luminance signal data.
With
The arithmetic processing step is
A storage step for storing the value of the threshold output signal, which is the value of the first brightness signal data or the second brightness signal data, corresponding to the lower limit temperature acceptable in the measurement of the temperature of the measurement object.
When at least one of the first luminance signal data and the second luminance signal data is equal to or less than the value of the threshold output signal, monitoring for determining that the temperature of the object to be measured is not normally measured. Steps and
A temperature measurement method.

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