JP6972728B2 - Temperature measuring device and temperature measuring method - Google Patents

Description

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

The radiation temperature measurement method is a method of knowing the temperature of a target object by detecting the thermal radiation light emitted by the object according to the temperature with a measuring device such as a radiation thermometer, and can measure the temperature at high speed without contact. It is a remote temperature measurement method. Today, many industries, including the steel industry, use this radiant temperature measurement method.

For example, in the continuous casting process and hot-rolling process of the steel manufacturing process, it is frequently performed to grasp the temperature of the steel material from both the viewpoints of process control and material quality, and the red-hot steel material moving on the transfer line. The above radiation temperature measurement method is used to measure the temperature in a non-contact manner. However, cooling water may stay on the steel material or steam may be generated by the evaporated water between the place where the slab is pulled out from the continuous casting machine and the rolling stands in the hot rolling process. It is known that when a radiation thermometer is used in such a situation, accurate temperature measurement cannot be performed because the heat radiant light from the object to be measured is absorbed by water and scattered by steam. That is, in general monochromatic radiation temperature measurement, it is not possible to know from the observed value whether the synchrotron radiation is attenuated by the disturbance of water or steam, or whether the temperature is really lowered.

One of the countermeasures taken at the manufacturing site today is to blow out purge gas on the optical path in the field of view of the radiation thermometer to remove water and steam. For example, in the temperature measurement of a slab of a continuous casting machine, the method of Patent Document 1 below has been proposed. However, even when the method of Patent Document 1 below is used, it may not be possible to effectively reduce the influence of disturbance depending on the amount and flow of water on the steel material. Further, when trying to use the method of Patent Document 1 below, it may not be possible to route the pipe for ejecting the purge gas close to the measurement target due to the structure of the equipment.

On the other hand, as one of the conventional radiation temperature measurement methods, there is a temperature measurement method using a two-color radiation thermometer, which is used when synchrotron radiation is attenuated due to fluctuations in emissivity or lack of field of view of a detector. The two-color radiation thermometer observes thermal radiant light at two wavelengths and removes the effects of the disturbance on the assumption that disturbances (fluctuations in emissivity, dimming due to lack of visual field) occur at the two wavelengths as well. However, with regard to the temperature measurement of steel materials as described above, a two-color radiation thermometer is useful if the disturbance element is only scattering attenuation due to steam, but when water is present on the steel material, the spectral absorption rate of water is strong. Since it has wavelength dependence, the assumption that the attenuation of the emitted light occurs at the two wavelengths does not hold, and there is a problem that accurate temperature measurement cannot be performed.

Japanese Unexamined Patent Publication No. 2012-71330

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is that the heat radiated light from the object to be measured is attenuated by an absorber or a scatterer existing on the optical path. under circumstances, without knowing the attenuation amount of the thermal radiation light by the absorber or scatterer in advance, more temperature measuring device which can measure the temperature due to radiation thermometry with high accuracy and temperature measuring how the To provide.

In order to solve the above problems, according to a certain viewpoint of the present invention, it is a temperature measuring device that measures the temperature of the object to be measured based on the thermal radiation in the near infrared band emitted by the object to be measured. An absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters thermal radiation light are present in at least a part of the optical path. The measurement unit that measures the radiation brightness of the thermal radiation of the measurement object at three different wavelengths and generates measurement data, and the measurement data corresponding to the three types of wavelengths are the first measurement data, respectively. When the second measurement data and the third measurement data are used, the first second color ratio is calculated by dividing one of the first measurement data and the second measurement data by the other, and the first measurement data and the above are described. The second second color ratio is calculated by dividing one of the third measurement data by the other, and the spectral emission rate of the measurement object at the three types of wavelengths is known, or the measurement object is said to have the spectral emission rate. Under the assumption that the spectral emission rates at the three types of wavelengths are equal, two relational expressions showing the relationship between the first two-color ratio or the second two-color ratio and the temperature of the object to be measured are expressed in a simultaneous equation. It has an arithmetic processing unit that calculates the temperature of the object to be measured, and at least two of the three types of wavelengths are from the band in which the spectral absorption coefficient of the absorber has wavelength dependence. A temperature measuring device of choice is provided.

Further, in order to solve the above-mentioned problems, according to another viewpoint of the present invention, a temperature measuring device for measuring the temperature of the measurement object based on the thermal radiation light in the near infrared band emitted by the measurement object. Therefore, an absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters the thermal radiation light are present in at least a part of the optical path. In this state, the measurement unit that measures the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths and generates measurement data, and the spectral emission rate of the object to be measured at the three wavelengths The temperature of the object to be measured and the thickness of the absorber at the three wavelengths, either known or under the assumption that the spectral emission of the object to be measured at the three wavelengths is equal. It also has an arithmetic processing unit that calculates the temperature of the object to be measured by solving three relational expressions showing the relationship of the transmittance of the scatterer as simultaneous equations, and has at least one of the three kinds of wavelengths. Two types are provided as a temperature measuring device in which the spectral absorption coefficient of the absorber is selected from the band having a wavelength dependence.

The absorber may be at least one of water, oil, solution, glass or resin.

Further, in order to solve the above problems, according to still another viewpoint of the present invention, a temperature measuring method for measuring the temperature of the measuring object based on the thermal radiation in the near infrared band emitted by the measuring object. Therefore, an absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters the thermal radiation light are present in at least a part of the optical path. In this state, the measurement step of measuring the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths to generate measurement data, and the measurement data corresponding to the three types of wavelengths are obtained. In the case of 1 measurement data, 2nd measurement data and 3rd measurement data, the 1st second color ratio is calculated by dividing one of the 1st measurement data and the 2nd measurement data by the other, and the 1st measurement data is calculated. The second color ratio is calculated by dividing one of the measurement data and the third measurement data by the other, and the spectral emission rate of the measurement object at the three types of wavelengths is known, or the measurement is performed. Two relational expressions showing the relationship between the first two-color ratio or the second two-color ratio and the temperature of the measurement object under the assumption that the spectral emission rates of the three kinds of objects are equal. Has an arithmetic processing step of calculating the temperature of the object to be measured by solving as simultaneous equations, and at least two of the three types of wavelengths have a wavelength-dependent spectral absorption coefficient of the absorber. A temperature measuring method selected from the band having the above is provided.

Further, in order to solve the above-mentioned problems, according to still another viewpoint of the present invention, a temperature measuring method for measuring the temperature of the measurement object based on the thermal radiation light in the near infrared band emitted by the measurement object. a is, an absorber for absorbing the chromatic thermally emitted light wavelength dependence on the spectral absorption coefficient definitive near infrared band, and scatterer which scatters thermal radiation light is present in at least a portion of the optical path In this state, the measurement step of measuring the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths to generate measurement data, and the spectral emission rate of the object to be measured at the three wavelengths. Is known, or the temperature of the object to be measured and the thickness of the absorber at the three wavelengths are assumed to be equal at the three wavelengths of the object to be measured. And an arithmetic processing step of calculating the temperature of the object to be measured by solving the three relational expressions showing the relationship of the transmission of the scatterer as simultaneous equations, and among the three kinds of wavelengths. At least two types provide a temperature measuring method in which the spectral absorption coefficient of the absorber is selected from the wavelength-dependent band.

As described above, according to the present invention, in a situation where the heat radiated light from the object to be measured is attenuated by the absorber or the scatterer existing on the optical path, the heat radiated light by the absorber or the scatterer is generated. It is possible to measure the temperature by the radiant temperature measurement method with higher accuracy without knowing the amount of attenuation in advance.

It is explanatory drawing for demonstrating the radiation temperature measurement method. It is explanatory drawing which showed the relationship between the attenuation of the observed light quantity and the calculated temperature. It is explanatory drawing which showed the wavelength dependence of the spectral absorption coefficient of water which is an example of an absorber. 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 the said embodiment. It is explanatory drawing which showed typically an example of the structure of the measuring part included in the temperature measuring apparatus which concerns on the said embodiment. It is a block diagram which showed an example of the structure of the arithmetic processing part included in the temperature measuring apparatus which concerns on the same embodiment. It is a flow chart which showed an example of the flow of the temperature measurement method which concerns on the same embodiment. It is a block diagram which showed an example of the hardware composition of the temperature measuring apparatus which concerns on the same embodiment. It is explanatory drawing which showed the spectral transmittance of water which is an example of an absorber. It is explanatory drawing which showed the relationship between the spectral radiance calculated from the blackbody radiation theory formula, and the temperature. It is explanatory drawing which showed the relationship between the two-color ratio and temperature. It is explanatory drawing which showed the relationship between the water film thickness and the calculated temperature.

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, and duplicate description will be omitted.

(About the problems of general radiation temperature measurement method)
Prior to explaining the temperature measuring device and the temperature measuring method according to the embodiment of the present invention, the problems of the general radiant temperature measuring method will be specifically described with reference to FIGS. 1 to 3. FIG. 1 is an explanatory diagram for explaining the radiation temperature measurement method, FIG. 2 is an explanatory diagram showing the relationship between the attenuation of the observed light amount and the calculated temperature, and FIG. 3 is an example of an absorber. It is explanatory drawing which showed the wavelength dependence of the spectral absorption coefficient of water.

FIG. 1 schematically shows the state of radiation temperature measurement accompanied by dimming on the optical path caused by an absorber such as water and a scatterer such as water vapor and steam. Further, when a measurement object having a true temperature of 800 ° C. and a spectral emissivity of 0.83 is measured with a monochromatic radiation thermometer having an observation wavelength of 750 nm, the above-mentioned absorber or scatterer may be used. The apparent temperature caused by the decay and observation of thermal radiation was calculated according to Planck's blackbody radiation equation. The obtained calculation result is shown in FIG.

Here, the wavelength of 750 nm is transparent to water, which is an example of an absorber, but if a water film is present on a measurement object such as a steel material, it is about 7% due to the interfacial reflection of water. The temperature measurement error due to the attenuation due to the interfacial reflection is about 5 ° C. Further, if the amount of light is halved by light scattering in steam or steam (that is, mist), a measurement error reaching 40 ° C. will occur, as is clear from FIG. As described above, the monochromatic radiation temperature measurement by the monochromatic radiation thermometer has an inherent error factor with respect to the attenuation occurring on the optical path of the thermal radiation light.

Further, in the radiation temperature measurement method, there is also a method of measuring the temperature using a two-color radiation thermometer instead of a monochromatic radiation thermometer. The temperature measurement method using this two-color radiation thermometer is a method of obtaining the temperature from the ratio of spectral radiance (two-color ratio), assuming that the spectral emissivity of the two wavelengths is the same as each other. The method using such a two-color radiation thermometer is an effective temperature measurement method if the dimming due to water absorption is the same between the two wavelengths, but the premise does not hold for the reason described below. That is, the spectral transmittance of water has a strong wavelength dependence as shown in FIG. 3, for example, the temperature function of the two color ratio and water described later assuming that the true temperature is 800 ° C. and the thickness of the water film is 10 mm. Using the spectral transmission characteristic data of the above, a temperature measurement error of 24 ° C. occurs at two wavelengths of 750 nm and 850 nm, and a temperature measurement error of 98 ° C. occurs at two wavelengths of 750 nm and 950 nm. In addition, if the two-color temperature measurement method is to be carried out in a narrow wavelength band near red where the water is transparent and the object to be measured emits observable radiation, two adjacent wavelengths will be used. There is a problem that the temperature change of the color ratio is small and the temperature measurement accuracy cannot be obtained.

In the above description, water is taken as an example as an absorber existing on the steel material to be measured, but in addition to water, glass, a solution existing on the steel material, and oils and fats existing on the steel material are used. Resins and the like also have non-uniform spectral absorption rates in the near-infrared band (that is, show strong wavelength dependence) and function as absorbers.

In addition, the situation where an absorber and a scatterer are present on the optical path between the object to be measured by the radiation temperature measurement method and the radiation thermometer is not limited to the steel manufacturing process such as the continuous casting process as described above, but also various other situations. This is a situation that can occur even in various measurement environments.

As described above, there is a problem that sufficient accuracy cannot be obtained by a general radiation temperature measurement technique in a place where an absorber or a scatterer exists on the optical path connecting the measurement object and the radiation thermometer.

(About the findings obtained by the present inventors)
As a result of diligent studies by the present inventors on the problems described above, the temperature of the object to be measured and the thermal radiation are absorbed by observing the thermal radiation of the object to be measured at three different wavelengths. We came up with the idea that the three unknowns, the thickness of the absorber and the amount of scattering attenuation due to the scattering element, can be obtained by calculation, and we were able to obtain the findings described in detail below.

Hereinafter, a method for calculating the temperature of the object to be measured from the spectral radiance observation values of three types of wavelengths used in the temperature measuring device and the temperature measuring method according to the embodiment of the present invention will be described in detail.

Now, let the temperature of the object to be measured be T [° C.], and let the three types of wavelengths observed by the radiation thermometer be λn (n = 1, 2, 3). In such a case, the spectral radiance L _b (λ _n ) at each wavelength is expressed by the following equation (1).

Here, in the above equation (1),
c ₁ : First constant of blackbody radiation, 1.19 × 10 ²⁰ [ ^Wm-2・ nm ⁴ ]
c _2: second constant of black body ^{radiation, 1.44 × 10 7 [nm ·} K]
β: Apparent transmittance due to scattering by the scatterer τ _n : Spectral transmittance of the absorber at wavelength λ _{n ε n} : Spectral emissivity at wavelength λ _n.

Here, the steam and water vapor (mist) existing on the optical path between the object to be measured and the radiation thermometer are scatterers having a diameter larger than the wavelength in the near-infrared band. In such a case, since the thermal radiation light is scattered by a scattering phenomenon called Mie scattering, the variable β in the above equation (1) can be considered to be constant regardless of the wavelength. That is, in the near-infrared band, the scattering characteristics of the scatterer can be considered to be uniform without wavelength dependence.

On the other hand, the spectral transmittance of water, which is an absorber, is described by the following equation (2) as the product of the transmittance _{τ 0 due to the interfacial return loss and the transmittance according to Lambert-Beer's law inside the water.} In the following equation (2), α _n is the spectral absorption coefficient at the wavelength λ _n , and t is the thickness of water.

Next, in order to eliminate the term expressing the effect of attenuating the thermal radiation light due to scattering by the scatterer, the above equation (1) is transformed into two types of two-color ratio equations, and the following equation ( 3) and (4) can be obtained. Here, the two-color ratio is a ratio of spectral radiance obtained by dividing the observed spectral radiance at one wavelength by the spectral radiance at another wavelength.

_{Here, R 1} (T) and R ₂ (T) in the above equations (3) and (4) are exponential functions that associate the two color ratios with the temperature, and the above equation (1) is used to describe the above. By expanding the left side of the equations (3) and (4), it can be expressed as the following equations (5) and (6).

_{However, R 1} (T) and R ₂ (T) derived from the theoretical formula (1) have a complicated form as is clear from the above formulas (5) and (6). Therefore, instead of the above equations (5) and (6), it is also possible to use an approximate equation (empirical equation) by polynomial approximation shown in the following equations (7) and (8).

Here, in the above formula (7) and _(8), a 2 ~a ₀ and _b 2 ~b ₀ is the coefficient of the polynomial. Further, since the coefficients a _{2 to} a ₀ and b _{2 to} b ₀ are constants determined by the observation wavelength and the temperature range of the object to be measured, they can be specified by actual measurement or simulation in advance. can.

Here, assuming that the spectral radiances of _{wavelengths λ 1} , λ ₂ , and λ ₃ obtained by observing the thermal _{radiance of the object to be measured are L 1} , L ₂ , and L ₃ , respectively, L ₁ is L ₂ . The divided two-color ratio becomes equal to the above equation (3), and _{the two-color ratio obtained by dividing L 1} by L ₃ becomes equal to the above equation (4). That is, the relationships represented by the following equations (9) and (10) are established.

Therefore, assuming that the approximate expression of the polynomial approximation represented by the above equations (7) and (8) is used as the concrete function form of the relational expressions R ₁ (T) and R _{2 (T), the above equation is used.} The equations (9) and (10) are as shown in the following equations (11) and (12). Here, in the following equations (11) and (12), E ₁ and E ₂ are the following equations (13) and (14).

Here, in the above equations (11) to (14), the spectral absorption coefficients α ₁ , α ₂ , and α ₃ of the absorber can be determined in advance by independently measuring the absorber that can exist on the optical path in advance. Can be grasped. Also, the relational expression R _{1 (T)} and R _{2 (T)} is, if you use those shown in Equation (5) and (6), that you calculate the specific function form in advance If the ones shown in the equations (7) and (8) are used, it is possible to specify a specific functional form by a preliminary simulation or actual measurement.

_{The spectral emissivity ε 1} , ε ₂ , and ε _{3 in the} above equations (13) and (14) are specified by measuring or simulating the spectral emissivity ε ₁ , ε ₂ , and ε _{3 in advance. Or by assuming that ε 1} = ε ₂ = ε ₃ holds in the observed wavelength band, the above E ₁ and E ₂ become constants. Then, the unknowns in the above equations (11) and (12) are two, the temperature T of the object to be measured and the thickness t of the absorber such as water. Therefore, by treating the above equations (11) and (12) as simultaneous equations, it is possible to calculate the temperature T of the object to be measured.

Here, the method of solving the simultaneous equations in which the temperature T of the object to be measured and the thickness t of the absorber are unknowns is not particularly limited, and 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.

As a result of further studies after obtaining the findings as described above, the present inventors have come up with the temperature measuring device and the temperature measuring method according to the embodiment of the present invention as described below. be.

(Embodiment)
<About the configuration of the temperature measuring device>
Subsequently, the overall configuration of the temperature measuring device 10 according to the embodiment of the present invention will be described in detail with reference to FIGS. 4A and 4B. 4A and 4B are explanatory views showing an example of the overall configuration of the temperature measuring device 10 according to the present embodiment.

The temperature measuring device 10 according to the present embodiment emits thermal radiation in the near-infrared band emitted by the object to be measured according to the temperature, an absorber having a wavelength dependence on the spectral absorption coefficient in the near-infrared band, and near. In the infrared band, both scatterers that do not have wavelength dependence on the spectral absorption coefficient are detected in a state where they are present in at least a part of the optical path, and the measurement object is measured based on the detection result of the radiation brightness of thermal radiation. It is a device that measures the temperature of. Here, examples of the absorber having a wavelength dependence on the spectral absorption coefficient in the near-infrared band include at least one of water, oil, solution, glass, and resin. As shown in FIG. 4A, 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 is emitted with respect to a measurement object that emits thermal radiant light mainly belonging to the visible light band to the near infrared band (for example, the band of 800 nm to 1400 nm), such as a steel material in a high temperature state. Measure the magnitude of the synchrotron radiation (observed light). At this time, the measuring unit 101 measures the thermal radiant light of the object to be measured at each of the three types of wavelengths, and generates measurement data showing the detection results of the radiance of the thermal radiant light at these three types of wavelengths.

Here, at least two of the three wavelengths are selected from the band having a wavelength dependence on the spectral absorption coefficient of the absorber.

The measuring unit 101 corresponds to an optical system including, for example, various lenses / lens groups in a radiation thermometer, sensors such as a photodetector, and the like. A more detailed configuration of the measuring unit 101 will be described again below.

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), an input device, an output device, 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 is derived from the measurement data generated by the measurement unit 101 corresponding to the three types of wavelengths and the plank blackbody radiation equation as described above, and the spectral radiance and temperature. The temperature of the object to be measured is calculated based on the relational expression between. The information regarding the temperature of the object to be measured calculated by the arithmetic processing unit 103 is output as an image via a display screen or the like, is output as a printed matter via a printer or the like, or is output as data itself.

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

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 parameters such as the spectral absorption coefficient of the absorber of interest, the spectral radiance of the object to be measured obtained by analyzing past operation data, and various constants in the above simultaneous equations. And data etc. are stored. In addition to these data, in the storage unit 105, various parameters that need to be stored when the temperature measuring device 10 according to the present embodiment needs to be stored, the progress of the processing, etc., or the progress of the processing, etc., 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.

As shown schematically in FIG. 4A, the measuring unit 101, the arithmetic processing unit 103, and the storage unit 105 may be realized inside one measuring device as, for example, one function of a 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. 4B. In the example shown in FIG. 4B, the functions of the measuring unit 101 and the storage unit 105 are realized inside the measuring unit that functions as a radiation thermometer, and the arithmetic processing device such as a personal computer, various servers, and various process computers is realized. The case where the functions of the arithmetic processing unit 103 and the storage unit 105 are realized inside is shown. In FIG. 4B, 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 101>
Subsequently, a configuration example of the measurement unit 101 according to the present embodiment will be briefly described with reference to FIG. FIG. 5 is an explanatory diagram schematically showing a configuration example of the measurement unit 101 according to the present embodiment.

As described above, the measuring unit 101 according to the present embodiment corresponds to the optical system in the radiation thermometer. As illustrated in FIG. 5, the measuring unit 101 has a lens 111 that guides the heat radiated light from the measurement object to a sensor 113 such as a photodetector described later, and the heat radiated light guided by the lens 111. Mainly includes a sensor 113 for detecting the light. Further, the measuring unit 101 further includes a wavelength selection filter 115 for selecting the wavelength of the thermal radiation light guided by the sensor 113.

Here, in FIG. 5, the lens 111 is schematically shown using one lens, but the lens 111 may be a lens group composed of a plurality of lenses. Further, the lens used for the lens 111 is not particularly limited, and known optical elements such as a spherical lens and an aspherical lens can be appropriately used.

The sensor 113 detects the spectral radiance of the thermal radiance from the object to be measured guided by the lens 111 at each of the three preset wavelengths (observation wavelengths), and obtains the obtained luminance signal data. Generate. After that, the sensor 113 outputs the obtained luminance signal 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.

The sensor 113 is not particularly limited, and any known sensor 113 can be used as long as it is suitable for the above-mentioned three types of wavelengths for detecting thermal radiation light. Examples of such a sensor (photodetector) include a detection element using Si, a detection element using InGaAs, and the like.

The wavelength selection filter 115 is a filter that selects the wavelength of the thermal radiation light guided by the sensor 113 and transmits the thermal radiation light having a specific wavelength to the sensor 113. As the wavelength selection filter 115, known ones can be used as long as they can transmit light of three preset wavelengths (observation wavelengths).

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. FIG. 6 is a block diagram showing a configuration example of the arithmetic processing unit 103 according to the present embodiment.

As illustrated in FIG. 6, the arithmetic processing unit 103 according to the present embodiment includes a measurement control unit 121, a data acquisition unit 123, a temperature calculation unit 125, a result output unit 127, and a display control unit 129. Mainly prepare.

The measurement control unit 121 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 121 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 121 controls the operation of the measurement unit 101 so as to measure the thermal radiation light from the measurement object at the three types of wavelengths as described above. Further, the measurement control unit 121 can output various set values such as measurement conditions for thermal radiation to the temperature calculation unit 125, if necessary.

The data acquisition unit 123 is realized by, for example, a CPU, a ROM, a RAM, a communication device, or the like. The data acquisition unit 123 acquires the luminance signals at the three types of wavelengths generated by the measurement unit 101 and outputs them to the temperature calculation unit 125, which will be described later. Further, the data acquisition unit 123 may associate the acquired luminance signals at the three 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 125 is realized by, for example, a CPU, a ROM, a RAM, or the like. The temperature calculation unit 125 uses the luminance signals at the three types of wavelengths output from the data acquisition unit 123 to obtain the luminance signal at any one of the first wavelength to the third wavelength and the remaining luminance signals. Two types of two-color ratio (in other words, the ratio of spectral radiance) divided by the luminance signal of any of the two wavelengths are calculated. Further, the temperature calculation unit 125 assumes that the calculated two-color ratio, the spectral absorption coefficient at the three wavelengths obtained in advance, and the spectral emissivity of the object to be measured at the three wavelengths are equal, or The temperature of the object to be measured is calculated based on the spectral emissivity of the object to be measured at the three types of wavelengths acquired in advance and the relational expression between the two-color ratio and the temperature.

Here, the spectral emissivity of the object to be measured at the three types of wavelengths acquired in advance may be used when the assumption that the spectral emissivity of the objects to be measured at the three types of wavelengths are equal to each other does not hold. It may be used even when the assumption is established. However, when the spectral emissivity of the objects to be measured at the three types of wavelengths is equal to (or can be regarded as equal to) each other, the calculation cost of the calculation to be performed can be reduced, so the three types acquired in advance. It is better not to use the spectral emissivity of the object to be measured at the wavelength of.

More specifically, the temperature calculation unit 125 uses the calculated two types of two-color ratios and solves simultaneous equations using the relational equations of the equations (9) and (10) shown in the above findings. , Calculate the temperature of the object to be measured. At this time, the temperature calculating unit 125, the formula (9) and the relationship _R 1 (T) and _R 2 (T) in the equation (10), Equation (5) and theoretical as shown in equation (6) An equation may be used, or an approximate equation as shown in the equations (7) and (8) may be used.

When the temperature calculation unit 125 calculates the two types of two-color ratio, any of the measurement data of the three types of wavelengths is used as the molecule on the left side of the formula (9) and the formula (10). It is not particularly limited whether or not the measurement data of the above is used as the denominator, and the reference measurement data may not be changed during the calculation process.

Further, the temperature calculation unit 125 does not calculate the temperature through the process of deriving the two types of two-color ratio R from the three types of luminance signals as described above, but is established for each of the three types of observation wavelengths 3. It is also possible to directly calculate the temperature by using the kind formula (1). That is, _{if the emissivity ε at the three wavelengths λ 1} , λ ₂ , and λ 3 is known, the temperature T, the thickness t of the water film, and the scatterer transmittance β are the three unknowns for each observation wavelength. There are three independent equations (1). Therefore, the temperature T can be calculated by simultaneously obtaining the solutions of the simultaneous equations by combining the three types of equations (1). Furthermore, even if the emissivity ε at the three types of wavelengths λ ₁ , λ ₂ , and λ _{3 is unknown, the emissivity ε at the wavelength λ 1} and the emissivity ε at the wavelength λ ₂ and the emissivity at the wavelength λ ₃ are unknown. Similarly, if the emissivity ε is equal to each other, it is possible to directly calculate the temperature T by combining the three types of equations (1).

The temperature calculation unit 125 outputs the information regarding the temperature T of the measurement object calculated as described above to the result output unit 127, which will be described later.

The result output unit 127 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, or the like. The result output unit 127 outputs the information regarding the temperature T of the measurement object output from the temperature calculation unit 125 to the user of the temperature measurement device 10. Specifically, the result output unit 127 associates the data corresponding to the temperature measurement result with the time data related to the date and time when the data was generated, and outputs the data to various servers and control devices, or outputs the data to a printer or the like. Output as a paper medium using the device. Further, the result output unit 127 may output the data corresponding to the determination result to various information processing devices such as a computer provided externally, or may output the data to various recording media.

Further, when the result output unit 127 outputs the data corresponding to the temperature measurement result to an output device such as a display provided in the temperature measuring device 10 or a display owned by various devices provided externally, the result output unit 127 outputs the data. , The determination result is output in cooperation with the display control unit 129 described later.

The display control unit 129 is realized by, for example, a CPU, a ROM, a RAM, an output device, a communication device, or the like. The display control unit 129 controls the display when displaying the data corresponding to the temperature measurement result 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 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 the time of implementing the present embodiment.

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, for example, via a network 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. 4A to 6.

<About the flow of temperature measurement method>
Subsequently, an example of the flow of the temperature measuring method carried out by the temperature measuring device 10 according to the present embodiment will be briefly described with reference to FIG. 7. FIG. 7 is a flow chart showing an example of the flow of the temperature measuring method according to the present embodiment.

As illustrated in FIG. 7, in the temperature measuring method according to the present embodiment, first, the measuring unit 101 of the temperature measuring device 10 is controlled by the measuring control unit 121 of the arithmetic processing unit 103 as described above. Thermal radiation from the object to be measured is measured at three wavelengths (more specifically, three wavelengths including at least two wavelengths at which the spectral absorption coefficient of the absorber indicates wavelength dependence) (step S101). As a result, the measuring unit 101 generates three types of luminance signals relating to the intensity of the detected thermal radiance (that is, spectral radiance) and outputs them to the arithmetic processing unit 103.

Next, the data acquisition unit 123 of the arithmetic processing unit 103 acquires the luminance signals of the spectral radiances at the three types of wavelengths output from the measurement unit 101 and outputs them to the temperature calculation unit 125.

The temperature calculation unit 125 calculates two types of two-color ratio R using the acquired luminance signals at the three wavelengths (step S103). Further, the temperature calculation unit 125 includes a relational expression showing the relationship between the two-color ratio and the temperature as shown in the above equations (5) to (14), and the spectral emissivity at three kinds of wavelengths acquired in advance. Based on the assumption that the spectral emissivity of the object to be measured at the three wavelengths is equal, or the spectral emissivity of the object to be measured at the three wavelengths obtained in advance and the calculated two-color ratio. The temperature T of the object to be measured is calculated by combining the two obtained relational expressions (step S105). After that, the temperature calculation unit 125 outputs the calculated information regarding the temperature T of the measurement object to the result output unit 127.

The result output unit 127 outputs the temperature of the measurement object calculated by the temperature calculation unit 125 (step S107). As a result, the user of the temperature measuring device 10 can grasp the information regarding the temperature T of the object to be measured.

As described above, the flow of the temperature measuring method according to the present embodiment has been briefly described with reference to FIG. 7.

(About hardware configuration)
Next, the hardware configuration of the temperature measuring device 10 according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 8 is a block diagram for explaining the hardware configuration of the temperature measuring device 10 according to the embodiment of the present invention.

The temperature measuring device 10 mainly includes a CPU 901, a ROM 903, and a RAM 905. Further, the temperature measuring device 10 further includes a host bus 907, a bridge 909, an external bus 911, an interface 913, a measuring unit 101, an input device 915, an output device 917, a storage device 919, a drive 921, a connection port 923, and a communication device 925. To prepare for.

The CPU 901 functions as a central processing device and a control device, and performs all or a part of the operation in the temperature measuring device 10 according to various programs recorded in the ROM 903, the RAM 905, the storage device 919, or the removable recording medium 927. Control. The ROM 903 stores programs, calculation parameters, and the like used by the CPU 901. The RAM 905 primaryly stores a program used by the CPU 901, parameters that are appropriately changed in the execution of the program, and the like. These are connected to each other by a host bus 907 composed of an internal bus such as a CPU bus.

The host bus 907 is connected to an external bus 911 such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge 909.

As described above, the measuring unit 101 detects the thermal radiant light from the object to be measured and measures the magnitude of the spectral radiance.

The input device 915 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 915 may be, for example, a remote control means (so-called remote controller) using infrared rays or other radio waves, or an externally connected device such as a mobile phone or a PDA that supports the operation of the temperature measuring device 10. It may be 929. Further, the input device 915 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 915, the user of the temperature measuring device 10 can input various data to the temperature measuring device 10 and instruct the processing operation.

The output device 917 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 917 outputs, for example, the results obtained by various processes performed by the temperature measuring device 10. Specifically, the display device displays the results obtained by various processes performed by the temperature measuring device 10 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 919 is a data storage device configured as an example of the storage unit of the temperature measuring device 10. The storage device 919 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 919 stores programs executed by the CPU 901, various data, various data acquired from the outside, and the like.

The drive 921 is a reader / writer for a recording medium, and is built in or externally attached to the temperature measuring device 10. The drive 921 reads out the information recorded on the removable recording medium 927 such as a mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory, and outputs the information to the RAM 905. The drive 921 can also write a record to a removable recording medium 927 such as a mounted magnetic disk, optical disk, magneto-optical disk, or semiconductor memory. The removable recording medium 927 is, for example, a DVD media, an HD-DVD media, a Blu-ray (registered trademark) medium, or the like. Further, the removable recording medium 927 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 927 may be, for example, an IC card (Integrated Circuit card) or an electronic device equipped with a non-contact type IC chip.

The connection port 923 is a port for directly connecting the device to the temperature measuring device 10. As an example of the connection port 923, there are a USB (Universal Serial Bus) port, an IEEE1394 port, a SCSI (Small Computer System Interface) port, and the like. Another example of the connection port 923 is an RS-232C port, an optical audio terminal, an HDMI (High-Definition Multimedia Interface) port, and the like. By connecting the externally connected device 929 to the connection port 923, the temperature measuring device 10 directly acquires various data from the externally connected device 929 and provides various data to the externally connected device 929.

The communication device 925 is, for example, a communication interface composed of a communication device or the like for connecting to the communication network 931. The communication device 925 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 925 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 925 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 931 connected to the communication device 925 is configured by a network connected by wire or wirelessly, and may be, for example, the Internet, a home LAN, infrared communication, radio wave communication, satellite communication, or the like. ..

The above is an example of a hardware configuration capable of realizing the function of the temperature measuring device 10 according to the embodiment of the present invention. Each of the above-mentioned components may be configured by using a general-purpose member, 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 the time of implementing the present embodiment.

Hereinafter, the temperature measuring device and the temperature measuring method according to the embodiment of the present invention will be specifically described while showing examples. The examples shown below are merely examples of the temperature measuring device and the temperature measuring method according to the embodiment of the present invention, and the temperature measuring device and the temperature measuring method according to the embodiment of the present invention are limited to the following examples. It is not something that will be done.

In this embodiment, the reddish steel material in the continuous casting process of the steel manufacturing process is taken as an example of the object to be measured, and water as an example of the absorber and steam or steam as an example of the scatterer are used as examples. , Focus on the case where it exists on the optical path.

In this example, the wavelength distribution of the spectral transmittance of water was measured, and the temperature (two-color ratio) and the spectral emissivity assuming the radiation temperature in the continuous casting process of the steel manufacturing process were investigated. The temperature of the steel material drawn from the continuous casting machine is, for example, 700 to 1100 ° C. with reference to past operation data and the like. In such a temperature range, it is possible to measure the temperature by the radiant temperature measurement method by setting the observation wavelength to approximately 800 nm or more.

FIG. 9 shows the spectral transmittance data of water obtained as a result of the measurement. As is clear from FIG. 9, since the absorption rate does not change according to the thickness of water up to a wavelength of around 820 nm, the transmittance in such a wavelength range is the attenuation rate τ due to the interfacial reflection between air and water. It can be regarded as _{0 (attenuation rate τ 0} in the above equation (2)). _{When τ 0} was read from the specifically obtained measurement data, _{it was τ 0} = 0.93.

In this example, by examining the spectral transmittance data shown in FIG. 9, 800 nm, 900 nm, and 1000 nm were selected as the _{three types of observation wavelengths λ 1} , λ ₂ , and λ _{3, respectively.} As is clear from FIG. 9, the wavelengths λ ₂ and λ ₃ are wavelengths belonging to the band in which the spectral absorption coefficient of water as an absorber shows wavelength dependence, and the wavelength λ ₁ is the spectroscopy of water as an absorber. It is a wavelength belonging to a band in which the absorption coefficient does not show wavelength dependence.

Here, attention is paid to _{the spectral absorption coefficients α 1} , α ₂ , and α ₃ of water at the above three wavelengths. As is clear from FIG. 9, the spectral absorption coefficient α ₁ is zero because there is no absorption by water. On the other hand, the spectral absorption coefficients α ₂ and α ₃ were calculated by reading the spectral transmittance from FIG. 9 and substituting the read spectral transmittance into the above equation (2). As a result, a spectral absorption coefficient alpha ₂ = .004568 wavelength lambda _2, was the spectral absorption coefficient alpha ₃ = 0.03112 wavelength lambda _3.

Next, we focused on the _{spectral emissivity ε 1} , ε ₂ , and ε ₃ in the wavelength band of 800 nm to 1000 nm. In this example, based on empirical knowledge, ε ₁ = ε ₂ = ε ₃ = 0.83 (constant). The reason for this is as follows. That is, it has been conventionally known that wustite (FeO) is formed as an oxide film on the surface of a steel material having a temperature of 600 ° C. or higher. The optical constant (material-specific complex refractive index) that determines the spectral emissivity of Wüstite has also been conventionally known, and this optical constant hardly changes in the wavelength band of 800 nm to 1000 nm. Therefore, since it can be confirmed theoretically that the spectral emissivity is constant, ε ₁ = ε ₂ = ε ₃ = 0.83 (constant) was set.

Subsequently, the blackbody spectral radiances at wavelengths of 800 nm, 900 nm and 1000 nm at 700 ° C. to 1100 ° C. were calculated using Planck's blackbody radiation formula, and the obtained results are shown in FIG. As is clear from FIG. 10, it can be seen that the blackbody spectral radiance increases as the temperature T increases. Further, in the wavelength band of interest in this embodiment, it can be seen that the longer the wavelength, the larger the spectral radiance. In this embodiment, using the three types of blackbody spectral radiance shown in FIG. 10, two types of two-color ratios corresponding to the left sides of the above equations (9) and (10) were calculated.

_{11 shows R 1} (T) obtained by dividing the spectral radiance at a wavelength of 800 nm in FIG. 10 by the spectral radiance at a wavelength of 900 nm, _{and R 2 obtained} by dividing the spectral radiance at a wavelength of 800 nm by the spectral radiance at a wavelength of 1000 nm. (T) and the calculation result. In this embodiment, the polynomial approximation equations shown in the above equations (7) and (8) are used as the function form of _{the relational expressions R 1} (T) and R _{2 (T), and such a function is shown in FIG.} Each coefficient was specified by fitting using the least squares method. As a result, a ₂ = -5.6559 x ^10-8 , a ₁ = 5.7594 x 10 ^-4 , a ₀ = -0.145, b ₂ = 1.6976 x ^10-7 , b ₁ = 6. 2068 × ¹⁰ _-5, it becomes b 0 = -5.16 × ^{10 -2.}

From the above studies, the constants and coefficients in the above equations (11) and (12) could be obtained. Using these constants and coefficients obtained, the usefulness of the temperature measuring method according to the embodiment of the present invention when applied to steel materials in a continuous casting process was verified by simulation.

First, when the temperature of the object to be measured is set to 800 ° C., heat radiation of three wavelengths of 800 nm, 900 nm and 1000 nm passes through the water film and is observed to be attenuated according to the spectral absorption coefficient as shown in FIG. The spectral radiances L ₁ , L ₂ , and L ₃ were calculated. Then, the obtained simulated observables of spectral radiances L ₁ , L ₂ , and L ₃ were substituted into the above equations (11) and (12) to obtain simultaneous equations. Subsequently, the solution of such simultaneous equations was solved as an optimum value problem. At this time, the thickness of the water film, which is an absorber, was changed, and it was confirmed what kind of value the obtained solution (that is, the calculated temperature of the object to be measured) showed.

The obtained results are shown in FIG. As is clear from FIG. 12, even when the thickness of the water film is changed from 1 mm to 30 mm, the obtained solution shows a value near 800 ° C. This result shows that the temperature of the object to be measured can be accurately calculated by using the temperature measuring method according to the embodiment of the present invention.

(summary)
As described above, according to the temperature measuring device and the temperature measuring method according to the embodiment of the present invention, thermal radiation is detected and calculated at three observation wavelengths in which the spectral absorption coefficient and the spectral emissivity of the absorber are known. It is possible to obtain the temperature of the measurement target. That is, for a problem with three variables of temperature, thickness of absorber, and attenuation due to scatterer, by obtaining three types of spectral radiance observations, the temperature is unknown by the arithmetic processing of solving simultaneous equations. Can be obtained. Therefore, it is possible to strictly correct the attenuation of the light on the optical path due to the absorber and the scatterer, and it is possible to realize highly accurate temperature measurement.

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 these 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 Lens 113 Sensor 115 Wavelength selection filter 121 Measurement control unit 123 Data acquisition unit 125 Temperature calculation unit 127 Result output unit 129 Display control unit

Claims (5)

A temperature measuring device that measures the temperature of the object to be measured based on the thermal radiation in the near-infrared band emitted by the object to be measured.
An absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters thermal radiation light are present in at least a part of the optical path. A measurement unit that measures the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths and generates measurement data.
When the measurement data corresponding to the three types of wavelengths are the first measurement data, the second measurement data, and the third measurement data, respectively, one of the first measurement data and the second measurement data is divided by the other. By doing so, the first color ratio is calculated, and by dividing one of the first measurement data and the third measurement data by the other, the second color ratio is calculated.
The first second color ratio under the assumption that the spectral emissivity of the measurement object at the three types of wavelengths is known, or the spectral emissivity of the measurement object at the three types of wavelengths is equal. Alternatively, an arithmetic processing unit that calculates the temperature of the object to be measured by solving two relational expressions showing the relationship between the second color ratio and the temperature of the object to be measured as simultaneous equations.
Have,
At least two of the three types of wavelengths are temperature measuring devices in which the spectral absorption coefficient of the absorber is selected from the wavelength-dependent band. A temperature measuring device that measures the temperature of the object to be measured based on the thermal radiation in the near-infrared band emitted by the object to be measured.
An absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters thermal radiation light are present in at least a part of the optical path. , A measurement unit that measures the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths and generates measurement data.
Under the assumption that the spectral emissivity of the measurement object at the three types of wavelengths is known, or the spectral emissivity of the measurement object at the three types of wavelengths is equal, the spectral emissivity at the three types of wavelengths is the same. , A calculation process for calculating the temperature of the object to be measured by solving as simultaneous equations three relational expressions showing the relationship between the temperature of the object to be measured, the thickness of the absorber, and the emissivity of the scatterer. Department and
Have,
At least two of the three types of wavelengths are temperature measuring devices in which the spectral absorption coefficient of the absorber is selected from the wavelength-dependent band. The temperature measuring device according to any one of claims 1 or 2, wherein the absorber is at least one of water, oil, solution, glass or resin. A temperature measuring method for measuring the temperature of the object to be measured based on the thermal radiation in the near infrared band emitted by the object to be measured.
An absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters thermal radiation light are present in at least a part of the optical path. A measurement step of measuring the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths and generating measurement data, and a measurement step.
When the measurement data corresponding to the three types of wavelengths are the first measurement data, the second measurement data, and the third measurement data, respectively, one of the first measurement data and the second measurement data is divided by the other. By doing so, the first color ratio is calculated, and by dividing one of the first measurement data and the third measurement data by the other, the second color ratio is calculated.
The first second color ratio under the assumption that the spectral emissivity of the measurement object at the three types of wavelengths is known, or the spectral emissivity of the measurement object at the three types of wavelengths is equal. Alternatively, an arithmetic processing step for calculating the temperature of the object to be measured by solving the two relational expressions showing the relationship between the second color ratio and the temperature of the object to be measured as simultaneous equations.
Have,
A temperature measuring method in which at least two of the three wavelengths are selected from the band in which the spectral absorption coefficient of the absorber has wavelength dependence. A temperature measuring method for measuring the temperature of the object to be measured based on the thermal radiation in the near infrared band emitted by the object to be measured.
An absorber that has a wavelength dependence on the spectral absorption coefficient in the near-infrared band and absorbs thermal radiation light and a scatterer that scatters thermal radiation light are present in at least a part of the optical path. A measurement step of measuring the radiation brightness of the thermal radiation of the object to be measured at three different wavelengths and generating measurement data, and a measurement step.
Under the assumption that the spectral emissivity of the measurement object at the three types of wavelengths is known, or the spectral emissivity of the measurement object at the three types of wavelengths is equal, the spectral emissivity at the three types of wavelengths is the same. , A calculation process for calculating the temperature of the object to be measured by solving as simultaneous equations three relational expressions showing the relationship between the temperature of the object to be measured, the thickness of the absorber, and the emissivity of the scatterer. Steps and
Have,
A temperature measuring method in which at least two of the three wavelengths are selected from the band in which the spectral absorption coefficient of the absorber has wavelength dependence.

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