JP2021139705A - Temperature measurement device, and temperature measurement method - Google Patents

Abstract

To more suppress a temperature measurement error.SOLUTION: According to the present invention, a temperature measurement device, which measures a temperature of a measurement object using a two-color emission temperature measurement, has: a light reception unit that receives thermal radiant light from a measurement object in a state where an absorber with wavelength dependency in 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 as a spectral luminance signal by using a spectral luminance meter; and a computation processing unit that obtains a temperature of the measurement object on the basis of the spectral luminance signal corresponding to two wavelengths in which the spectral transmittance of the absorber detected in the detection unit is identical. The computation processing unit is configured to: set a weight coefficient made of a consecutive unitless number in a wavelength direction; and obtain the temperature of the measurement object on the basis of the weight coefficient, a value of the spectral transmittance of the spectral luminance meter, and the spectral luminance signal.SELECTED DRAWING: Figure 9

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.

Especially in the steel industry, in the manufacturing process, water having the property of absorbing thermal radiation in the near-infrared band on the optical path between the object to be measured such as steel plate material and the measuring equipment such as a radiation thermometer Absorbents such as fats and oils are often present. In such a case, a part of the heat radiated 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. In Patent Document 1, in order to detect the radiance at two wavelengths having the same spectral absorption coefficient of the absorber, the radiance at a desired wavelength is extracted using two types of optical bandpass filters. , The extracted radiance is detected.

Japanese Unexamined Patent Publication No. 2019-23635

The present inventors further verified using the two-color radiation thermometer disclosed in Patent Document 1. As a result, at a certain temperature, the transmission band of the optical bandpass filter is selected so that the attenuation of the thermal radiation by the absorber is equal at the two wavelengths, and the radiation is emitted using the optical bandpass filter determined based on such selection. When the temperature was measured, it was found that the temperature measurement error may become large under the condition that the temperature of the object to be measured changes significantly. Especially in the steel industry, a steel material, which is an example of an object to be measured, often has various temperatures from a temperature of about 600 ° C to a temperature exceeding 1000 ° C, and the fluctuation range of the temperature to be measured is large. .. Therefore, if a temperature measurement error as recently found by the present inventors occurs, it becomes impossible to determine whether or not the temperature measurement value is an appropriate value.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a temperature measuring device and a temperature measuring method capable of further suppressing a temperature measuring error. be.

As a result of verification by the present inventors in order to solve the above problems, it has been found that the above temperature measurement error is caused by the characteristics of the optical bandpass filter. Various general optical filters, including the optical bandpass filter used in the two-color radiation thermometer disclosed in Patent Document 1, have optical characteristics of the optical filter at a typical temperature that can be measured. It is selected and determined to be in the desired state. Therefore, the present inventors have clarified that if the temperature of the object to be measured deviates significantly from the temperature at which the optical characteristics are determined, the above-mentioned temperature measurement error occurs. This is because the optical characteristics of the optical filter have a predetermined bandwidth, and therefore, when the temperature of the object to be measured changes, the effective center wavelength is affected by the temperature-dependent blackbody radiation spectrum. (For example, in the optical band path filter, the apparent center wavelength of the transmission wavelength band) changes, which is considered to be due to a measurement error.

As a result of further verification by the present inventors based on the above findings, the thermal radiation light from the object to be measured is detected by using a spectrophotometer capable of continuously measuring the spectrum of light. It was conceived that the above-mentioned temperature measurement error can be suppressed by performing predetermined data processing on the spectral brightness signal obtained by the spectral brightness meter.
The gist of the present invention completed based on the above findings is as follows.

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. Using a light receiving unit that receives the thermal radiation light from the measurement object and a spectrophotometer in a state where it can exist on the optical path to the measurement object, the spectral brightness of the thermal radiation light received by the light receiving unit is measured. The temperature of the object to be measured is measured based on the detection unit that detects as a spectral brightness signal and the spectral brightness signal that corresponds to two wavelengths of the absorber that have the same spectral transmittance detected by the detection unit. The arithmetic processing unit includes a desired arithmetic processing unit, and the arithmetic processing unit sets a weighting function composed of unclear numbers continuous in the wavelength direction, the weighting function, the value of the spectral transmission rate of the spectrophotometer, and the said. The temperature of the object to be measured is obtained based on the spectral brightness signal.

In the temperature measurement method according to the present invention, in the temperature measurement 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 transmission rate in the near infrared band is described above. Using a light receiving step that receives the thermal radiation light from the measurement object and a spectroscopic brightness meter in a state where it can exist on the optical path to the measurement object, the spectral brightness of the thermal radiation light received in the light receiving step is measured. The temperature of the object to be measured is determined based on the detection step detected as a spectral brightness signal and the spectral brightness signals detected in the detection step corresponding to two wavelengths at which the spectral transmittance of the absorber is the same. The arithmetic processing step includes the arithmetic processing step to be obtained, and the arithmetic processing step sets a weighting coefficient composed of a non-bright number continuous in the wavelength direction, the weighting coefficient, the value of the spectral transmission rate of the spectroscopic luminometer, and the said. The temperature of the object to be measured is obtained based on the spectral brightness signal.

As described above, according to the present invention, it is possible to further suppress the temperature measurement error when measuring the temperature of the object to be measured.

It is a graph for demonstrating the discrete signal in a spectroluminometer. It is explanatory drawing for demonstrating the weighting function of interest in embodiment of this invention. It is explanatory drawing for demonstrating the weighting function of interest in embodiment of this invention. It is explanatory drawing for demonstrating the weighting function of interest in embodiment of this invention. It is explanatory drawing for demonstrating the weighting function of interest in embodiment of this invention. It is explanatory drawing for demonstrating the weighting function which has a trapezoidal distribution. It is a graph which showed an example of the weighting function which has a trapezoidal distribution. It is a graph which showed the spectral transmittance of the water film of a thickness of 10 mm. It is a graph which showed the wavelength distribution of a blackbody spectral radiance. It is a graph which showed an example of the weighting function applied to the wavelength band on the long wavelength side. 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 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 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 by the present inventors)
Prior to explaining the temperature measuring device and the temperature measuring method according to the embodiment of the present invention, various studies on the two-color radiation thermometer carried out by the present inventors will be described in detail with reference to FIGS. 1 to 7. do.
FIG. 1 is a graph for explaining discrete signals in a spectroluminometer. 2A to 3 are explanatory views for explaining the weighting function of interest in the embodiment of the present invention. FIG. 4 is a graph showing an example of a weighting function having a trapezoidal distribution. FIG. 5 is a graph showing the spectral transmittance of a water film having a thickness of 10 mm. FIG. 6 is a graph showing the wavelength distribution of blackbody spectral radiance. FIG. 7 is a graph showing an example of a weighting function applied to the wavelength band on the long wavelength side.

In the two-color radiation thermometer disclosed in Patent Document 1 proposed by the present inventors, as a method for observing light of a specific wavelength, an optical bandpass filter is placed in front of a photodetector such as an InGaAs element. However, other methods can be adopted as a method for observing light having a specific wavelength. In order to suppress the temperature measurement error caused by the optical bandpass filter as described above, the present inventors can continuously detect the spectrum of light instead of the combination of the optical bandpass filter and the photodetector. In other words, I came up with the idea of using a spectrophotometer (which can measure the spectral distribution of light). It can be said that such a spectral luminance meter is a detector that disperses incident light for each wavelength, detects the spectral luminance of light at each wavelength, and outputs the detected spectral luminance as a spectral luminance signal.

In the temperature measuring device according to the present embodiment, such a spectroscopic brightness meter is used to obtain a continuous spectral brightness signal for a wavelength, and then a signal in a desired wavelength band is extracted from the spectral brightness signal and used. Therefore, it is possible to obtain the same function as the two-color radiation thermometer shown in Patent Document 1 proposed by the present inventors.

Further, in the temperature measuring device according to the present embodiment, by using such a spectrophotometric meter, it is possible to suppress the measurement error caused by the optical bandpass filter as described above, and it is possible to suppress the measurement error for each of a plurality of measurement wavelengths individually. There is no need to prepare an optical bandpass filter. Therefore, the measurement at each wavelength becomes easy, the flexibility when changing the conditions such as the wavelength can be increased, and the measuring device can be simplified and the cost can be reduced.

On the other hand, the two-color radiation thermometer proposed by the present inventors in the present embodiment is determined by selecting and determining the detection wavelength very precisely, as in the case of the two-color radiation thermometer disclosed in Patent Document 1. Specifically, unless the detection wavelength is set with an accuracy of 0.5 nm or less, it becomes difficult to obtain sufficient accuracy. Here, the problem is that the spectral luminance signal obtained from a general spectroluminance meter does not have a detection resolution of 0.5 nm or less. For example, in a spectroluminometer currently on the market, the sampling interval of the spectrum (in other words, the wavelength resolution) is about 1.7 nm. That is, when a general spectrophotometer is used, the wavelength at which the measured value is obtained is determined depending on the sampling interval. Therefore, about 1.7 nm from an arbitrary measurement wavelength at which the measured value is actually obtained. It is difficult to actually measure the spectral brightness signal at wavelengths deviated by the following wavelength widths.

Using such a spectroluminometer, the wavelength at which the spectral transmittance at a predetermined wavelength (for example, 1210 nm) is the same as the spectral transmittance (indicated by ■ in FIG. 1) with a resolution smaller than the sampling interval. For example, in the graph of FIG. 1 _{, a horizontal line is drawn from the value of the spectral transmittance (S 1210} ) at the predetermined wavelength, the intersection point where the graph intersects is searched again, and the spectral transmission shown in FIG. 1 is determined. Among the measured values of the rate (indicated by ◯ in FIG. 1), the average value may be obtained from the wavelengths of two adjacent measured values (for example, 1290 nm and 1310 nm) straddling the intersection. A schematic representation of this concept is shown in FIG. In FIG. 1, in order to make the explanation easier to understand, the sampling interval of the spectroluminometer is enlarged.

In the temperature measuring device of the present embodiment, the spectral absorption coefficient (spectral transmission rate) of the absorber (hereinafter, water will be described as an example) as disclosed in Patent Document 1 may be considered. As the wavelengths at which (possible) are equal, attention is paid to the wavelength band near 1200 nm (the wavelength band on the short wavelength side) and the wavelength band near 1300 nm (the wavelength band on the long wavelength side). In FIGS. 1 and 2A to 2D, 1210 nm is used as a reference as the wavelength of the wavelength band on the short wavelength side in order to make the explanation easy to understand.

In the two-color radiation thermometer of the present embodiment, it is necessary to use spectral luminance signals of two wavelengths in which the spectral transmittances of the absorbers match, but this is due to the fact that the present embodiment uses the spectral luminance meter. , The spectral luminance signal cannot be actually measured at a wavelength interval shorter than the sampling interval of the spectral luminance meter. Therefore, as shown in FIG. 1, the wavelengths at which the wavelength ₁₂₁₀ nm (spectral transmittance is S 1210) and the spectral transmittance match are the wavelength ₁₂₉₀ nm (spectral transmittance S 1290) and the wavelength 1310 nm (spectral transmittance S _1310). ), It corresponds to the wavelength for which the measured value does not exist.

In the above case, since there is no actually measured value of the wavelength on the long wavelength side where the wavelength band on the short wavelength side and the spectral transmittance exactly match, the calculation for dividing the spectral luminance signal in the vicinity is performed. .. In this case, if the accuracy of the obtained spectral luminance signal is not particular, weights are given to the two nearby spectral luminance signals S ₁₂₉₀ and S _{1310 , for example, 0.4 × S 1290} + 0.6 × S _1310. It is sufficient to perform the calculation of synthesizing the luminance values so that the spectral transmittance is equal to that of the short wavelength side by averaging after adding.

However, in order to ensure the accuracy of the spectral luminance signal in order to make the spectral transmittances of the absorbers the same, the concept as shown in FIG. 1 is generalized and the spectral luminance from the spectroluminance meter is generalized. It is necessary to determine the spectral luminance signal at a wavelength at which the measured value of the signal does not exist with high accuracy. Therefore, the present inventors have come up with the idea of using a weighting coefficient of 0 or more and 1 or less and a plurality of (particularly, a large number of) spectral luminance signals located in the vicinity of a desired wavelength. .. Hereinafter, such a concept will be described with reference to FIGS. 2A to 3.

The temperature measuring device according to the present embodiment measures the temperature in a state where an absorber such as water having a wavelength dependence on the spectral transmittance in the near infrared band can exist on the optical path to the object to be measured. Since it is assumed, it is necessary to grasp the optical characteristics of the absorber in advance. Therefore, the spectral transmittance of the absorber is measured in advance for each wavelength using the temperature measuring device itself according to the present embodiment. For example, the spectral transmittance can be measured by measuring the spectral luminance signal by changing the presence or absence of the absorber for each wavelength. The results thus obtained are shown in the upper figure of FIG. 2A.

Since the upper figure of FIG. 2A is measured by using the temperature measuring device (spectral luminance meter) according to the present embodiment, the measured value of the spectral transmittance (indicated by ◯ in the figure) is the present embodiment. Sampling interval of the temperature measuring device (spectral luminance meter) according to the above (indicated by Δ in the figure. Originally, for example, the interval is 1.7 nm, but in the figure, it is drawn at a large interval for simplicity of explanation). Appears at wavelength intervals according to.

In addition, in the case of obtaining the relationship between the wavelength and the spectral transmittance as shown in the upper figure of FIG. 2A, if the measurement is performed using the temperature measuring device itself according to the present embodiment, the temperature measuring device itself becomes It is preferable because the optical characteristics of the measurement can be reflected in the measurement result. However, the method is not limited to these methods, and for example, measurement should be performed using another measuring device, or the wavelength dependence of the spectral transmittance of the absorber should be grasped from materials such as known literature. You may do it.

Further, since the temperature measuring device according to the present embodiment measures the temperature of the object to be measured by using the two-color radiation temperature measurement, it is necessary to measure the brightness of the heat radiation emitted by the object to be measured. Therefore, using the temperature measuring device (spectral luminance meter) according to the present embodiment, the spectral luminance of the object to be measured is measured for each wavelength in a state where the absorber can exist on the optical path to the object to be measured. Measure as. The results thus obtained are shown in the lower figure of FIG. 2A.

Since the lower figure of FIG. 2A is also obtained by measuring with the temperature measuring device (spectral luminance meter) according to the present embodiment, the measured value of the spectral luminance shown in the lower figure of FIG. 2A (circled in the figure). (Shown) are wavelength intervals corresponding to the sampling interval Δ of the temperature measuring device (spectral luminance meter) according to the present embodiment, and are the measured values of the spectral transmittance in the upper figure of FIG. 2A (indicated by ◯ in the figure). ) Appears at the same wavelength.

Next, in order to obtain a spectral luminance signal at a wavelength (indicated by ■ in FIG. 1) that deviates from the sampling wavelength of the spectral luminance meter and in which the measured value of the spectral luminance signal does not exist, the distribution as shown in FIG. 2B (example). Prepare a weighting function with a triangular distribution).

The weighting function is continuous in the wavelength direction (may be a discrete value as long as the interval is significantly narrower than the sampling interval Δ) regardless of the sampling interval Δ of the spectroluminometer, and is in the wavelength direction. It is set as a function having an unnamed number (weighting coefficient, preferably a value of 0 to 1) that becomes a weight on an axis different from the above. Further, the weighting function can be set by appropriately changing the position of the apex (indicated by ■ in FIG. 2B) in the wavelength direction.

Next, as shown in FIG. 2C, in the relationship between the wavelength shown in the upper figure of FIG. 2A and the spectral absorption coefficient, the position of the apex ■ of the weighting function in the wavelength direction is set in the wavelength band on the short wavelength side of interest. Set so that the position is at the reference wavelength (1210 nm). In that state, a calculation (convolution calculation) for multiplying the spectral transmittance and the weighting function is performed at each wavelength for each sampling interval Δ, and the total value (hereinafter, referred to as short wavelength side weighting data) is stored. In the example shown in FIG. 2C, after the apex of the weighting function _{is aligned with S 1210} in the wavelength direction, the measured value of the spectral transmittance is the measured value of the spectral transmittance centering on the range where the measured value of the spectral transmittance and the weighting function overlap. Multiply a ₁ , a ₂ , a _3, ... a ₅ by the weighting coefficients b ₁ , b ₂ , b ₃ ... b ₅ determined by the weighting function, and add them together (a ₁ b ₁ + a ₂ b ₂ + a). ₃ b ₃ + ... a ₅ b ₅ ) to acquire the weighted data on the short wavelength side.

Next, as shown in the upper figure of FIG. 2D, in the relationship between the wavelength and the spectral transmittance shown in the upper figure of FIG. 2A, the position of the apex ■ in the wavelength direction is (short wavelength side). It is set to be on the left side (short wavelength side) of the wavelength 1290 nm (there is an actual measurement value adjacent to the short wavelength side) at a wavelength whose spectral transmittance matches that of 1210 nm, which is the reference of the above. In that state, a calculation (convolution calculation) for multiplying the spectral transmittance and the weighting coefficient is performed at each wavelength for each sampling interval Δ, and the total value (hereinafter, referred to as long wavelength side weighting data) is stored. In the example shown in the upper figure of FIG. 2D, _{after aligning the apex of the weighting function with the left side of S 1290} in the wavelength direction, the spectral transmittance is centered on the range where the measured value of the spectral transmittance and the weighting function overlap. Multiply the measured values of c ₁ , c ₂ , c _3, ... c ₅ by the weighting coefficients d ₁ , d ₂ , d ₃ ... d ₅ determined by the weighting function, and add them up (c ₁ d _1). + C ₂ d ₂ + c ₃ d ₃ + ... c ₅ d ₅ ), and the long wavelength side weighted data is acquired.

Then, as shown by the weighting function of the broken line in the upper figure of FIG. 2D, the position of the apex ■ of the weighting function in the wavelength direction is set to the right by a minute interval (interval σ (that is, σ << Δ) sufficiently narrower than the sampling interval Δ). Move to (long wavelength side). Then, again, at the wavelength for each sampling interval Δ in which the spectral luminance signal is obtained, the calculation of multiplying the spectral transmittance and the weighting coefficient is performed, and the long wavelength side weighted data which is the total value thereof is stored.

While repeating the calculation and storage accompanying the movement of the weighting function, as shown in the lower figure of FIG. 2D, the position of the apex ■ in the wavelength direction is (1210 nm, which is the reference on the short wavelength side, and the spectral transmittance is 1210 nm. The stored long wavelength side weighted data matches the short wavelength side weighted data while moving to the right side (long wavelength side) of the wavelength 1310 nm (which has the measured value adjacent to the matching wavelength on the long wavelength side). Check if it is. Then, when they match, the weighting function is fixed at the position in the wavelength direction where the weighting coefficient is located at that time.

The weighting function whose position is fixed in this way has a spectral transmittance with a wavelength of 1210 nm as a reference in the wavelength band on the short wavelength side and no measured value in the wavelength band on the long wavelength side (between wavelengths 1290 nm and 1310 nm). As a virtual optical filter having weighting and wavelength information so that the spectral transmittances obtained from a plurality of measured values in the surroundings, which are shown in FIG. It will have a function.

Subsequently, in order to obtain a desired spectral brightness signal, the position of the weighting function in the wavelength direction is set to a wavelength of 1210 nm at the wavelength on the short wavelength side, and then the weighting function is set to the spectral brightness signal shown in the lower figure of FIG. 2A. Multiply the measured value of. On the other hand, at the wavelength on the long wavelength side, the weighting function whose position is fixed is multiplied by the measured value of the spectral luminance signal shown in the lower figure of FIG. 2A.

By doing so, the spectral brightness on the short wavelength side and the spectral brightness on the long wavelength side are provided under the condition that the short wavelength side and the long wavelength side have effectively the same spectral transmittance with respect to the water as an absorber. Can be obtained.

Therefore, by calculating the ratio (two-color ratio) between the spectral brightness on the short wavelength side and the spectral brightness on the long wavelength side without being affected by the attenuation of synchrotron radiation by water, it is based on the principle of two-color radiation temperature measurement. Therefore, the temperature of the object to be measured can be obtained accurately.

By applying such a weighting function to a two-color emission thermometer using a spectroluminance meter, it is possible to solve the problem that the spectroluminance meter is actually measured only at each sampling interval, and FIG. _{Not only the spectral luminance signals of only two points (S 1290} and S ₁₃₁₀ ) as shown in the above, but also more spectral luminance signals (measured values) can be incorporated into the convolution calculation, so that the spectral luminance has noise and variation. The signal can be averaged at multiple points, and the accuracy can be further improved.

By the way, for example, in order to obtain a virtual resolution having a wavelength of 1.7 nm or less, the distribution of the weighting function may have a region inclined in the wavelength direction having a value larger than 0 and smaller than 1. Then, considering that the number of spectral luminance signals required for smoothing by multipoint averaging is appropriately used, even if the weighting function does not have the triangular distribution as described above, for example, it is schematically shown in FIG. Such a weighting function having a trapezoidal distribution may be used.

When a weighting function having a trapezoidal shape distribution is used, a large value corresponding to the upper side of the trapezoidal shape is weighted and emphasized around the central wavelength of each wavelength band on the short wavelength side and the long wavelength side. On the other hand, at wavelengths that deviate significantly from the center wavelength of each wavelength band on the short wavelength side and the long wavelength side, a small value corresponding to the oblique side of the trapezoidal shape is weighted and weakened. You will be able to select more accurately.

In the example shown in FIG. 3, a case where a spectral luminance signal having a desired wavelength is obtained by using 10 spectral luminance signals is illustrated. Further, the weighting coefficient constituting the weighting function shown in FIG. 3 may be set as a continuous function, or may be composed of a plurality of points having narrowed intervals in the wavelength direction as shown in FIG.

The averaging process (convolution calculation process) using the weighting function as shown in FIGS. 2B, 3 and 4 can be considered as a virtual optical filter (virtual optical filter, digital filter) as described above. It can also be considered as a filtering process using). Such a weighting function can actually be determined in advance experimentally or by simulation so that the temperature measurement error due to the presence or absence of the absorber is eliminated. In this case, the number of spectral brightness signals to be used and the distribution of weighting coefficients in the weighting function (distribution of weighting coefficients as shown in FIGS. 3 and 4) according to the sampling interval and noise sensitivity of the spectral brightness meter to be used. It is important to determine the shape of the short wavelength side and the long wavelength side virtual optical filter.

Next, a phenomenon in which the two wavelengths at which the spectral transmittances of the absorbers should match slightly changes depending on the temperature and a point that the above phenomenon can be solved by using a spectroluminometer will be described below.

In the two-color radiation thermometer disclosed in Patent Document 1, a physical optical filter (optical bandpass filter) was used. In this case, the optical bandpass filter is not a narrow band filter capable of regarding the transmitted light of the filter as a single wavelength, but has a certain range of transmitted wavelengths, for example, transmitted wavelength width = about 50 nm. Things are used. This is because an optical bandpass filter having a narrow transmission wavelength band may not have sufficient radiance for stable operation of an infrared photodetector such as an InGaAs element.

The present inventors measured the temperature of a measurement object (steel material) capable of taking a temperature of 600 to 1200 ° C. using a two-color radiation thermometer equipped with an optical bandpass filter as described above. As a result, at 900 ° C., which is the temperature at which the optical characteristics of the optical bandpass filter are determined, the temperature measurement result does not change (that is, a measurement error occurs) depending on the presence or absence of water as an absorber, but on the other hand. It was found that when the temperature of the object to be measured is 600 ° C. and the temperature of the object to be measured is 1200 ° C., a temperature measurement error of about ± 5 ° C. occurs depending on the presence or absence of the absorber. That is, the verification by the present inventors has revealed that the two wavelengths at which the spectral transmittances of water, which is an absorber, are equal to each other are temperature-dependent.

When a physical optical filter has a finite transmission wavelength width, it is important to consider the average (effective) transmission of the transmission width. Therefore, the present inventors investigated the observed light amount of the two-color radiation thermometer by spectroscopic simulation. In the spectroscopic simulation shown below, the spectral transmittance of water as an absorber, the spectral transmittance of an optical filter, and the blackbody spectral radiance are expressed by a discrete spectrum with a sampling interval Δ = 1.7 nm. bottom.

First, as a weighting function on the short wavelength side, a weighting function was used in which the distribution of the weighting coefficients was trapezoidal and symmetrical as shown in FIG. 3, and the following conditions were satisfied. The weighting function is a trapezoid in which the weighting coefficient is 1 over a wavelength width of 60 nm (that is, the length of the upper base is 60 nm), and the weighting coefficient linearly decreases from 1 to 0 in a region having a width of 10 nm at both ends thereof. The shape was taken.

Based on the above conditions, the weighting function of the central transmission wavelength = 1200 nm is expressed in wavelength increments of the sampling interval Δ = 1.7 nm, as shown in FIG.

As the weighting function for the vicinity of 1300 nm on the long wavelength side, the same weighting function as the weighting function on the short wavelength side was used. Here, the weighting function on the long wavelength side so that the principle of the two-color radiation thermometer holds (that is, the effective transmittance of water, which is an example of the absorber, becomes equal to the effective transmittance on the short wavelength side). The central transmission wavelength of is searched by simulation. Here, as shown in FIG. 5, the spectral transmittance of water changes monotonically in the vicinity of 1300 nm. Therefore, the effective transmittance based on the weighting function can be adjusted by adjusting the center transmission wavelength.

As the spectral transmittance of water, known data can be used, and as such data, for example, the spectral transmittance of water when the thickness of the water film = 10 mm as shown in FIG. 5 is mentioned. be able to. As is clear from FIG. 5, there are two wavelengths having the same spectral transmittance in the vicinity of the wavelength of 1200 nm and in the vicinity of the wavelength of 1300 nm. It can be seen that the spectral transmittance of water decreases monotonically near a wavelength of 1300 nm.

_{To obtain the effective transmittance τ eff} of the weighting function by paying attention to the spectral transmittance of water as described above, simply considering, the effective transmittance τ _eff shown in the following equation (1) has a central transmission wavelength of 1200 nm. It means that the central transmission wavelength of the weighting function on the long wavelength side is selected so as to be equal to the weighting function of.

Here, in the above equation (1), λ ₁ is the lower limit transmission wavelength of the weighting function, n is the number until the upper limit transmission wavelength is reached in Δ increments, and τ (λ) is water at the wavelength λ. F (λ) is a weighting coefficient corresponding to the spectral transmittance of the optical filter at the wavelength λ.

As described above, when the weighting function of the central transmission wavelength of 1200 nm and the central transmission wavelength having the same effective transmittance were obtained, the central transmission wavelength was 1284.04 nm. Therefore, it is bilaterally symmetric at the central transmission wavelength = 1284.04 nm, the weighting coefficient is 1 over a wavelength width of 60 nm, and the weighting coefficient linearly decreases from 1 to 0 in a region having a width of 10 nm at both ends (Fig.). It is a trapezoid with the same shape as that shown in 4, but by using a weighting function with a center wavelength of 1284.04 nm), the effective transmittance of water, which is an absorber, can be obtained from the spectral brightness signal obtained from the spectrophotometer. It is conceivable to obtain two types of spectral brightness signals in which are equal to each other. However, the method of determining the weighting function of the equation (1) cannot explain the phenomenon that a measurement error occurs due to the presence or absence of water depending on the temperature of the measurement target.

Therefore, the inventors examined further and came up with the following. That is, instead of using a weighting function that considers only the effective transmittance of the absorber as in the above equation (1), the wavelength dependence of blackbody radiation is also considered in addition to the effective transmittance as described below. It is preferable to use a weighting function.

Blackbody radiation emitted from a heat-bearing object has spectral characteristics depending on the temperature, and the spectral radiance is not uniform even within the transmission wavelength range of the optical filter. Therefore, as the effective transmittance τ _eff , not only the weighting coefficient corresponding to the spectral transmittance for each wavelength and the spectral transmittance of water but also the wavelength dependence (wavelength distribution) of the spectral emission brightness of the black body radiation is further considered. By doing so, it becomes possible to further improve the optical characteristics (wavelength characteristics) of the weighting function. _{At this time, the effective transmittance τ eff} is given by the following equation (2) in consideration of the weight w (λ) in consideration of the wavelength distribution of the spectral radiance of blackbody radiation.

Here, as the weight w (λ) of the blackbody spectral radiance, for example, as illustrated in FIG. 6, a relative value of the blackbody spectral radiance based on the wavelength of 1250 nm can be used.

_{Based on the effective transmittance τ eff} shown in the above formula (2), the central transmission wavelength having the same effective transmittance as the weighting function of the central transmission wavelength of 1200 nm was obtained. As a result, when the temperature to be measured was 600 ° C., the central transmission wavelength was 1287.97 nm, and when the temperature to be measured was 1200 ° C., the central transmission wavelength was 1286.84 nm. The distribution of the weighting coefficients of these weighting functions is summarized in FIG. 7.

By using the weighting function as described above, the spectral luminance signal of the desired wavelength is obtained by resynthesizing the luminance signal once dispersed for each wavelength by using the continuous spectrum obtained from the spectroscopic luminance meter. Can be extracted. As a result, using the extracted spectral brightness signal, the two-color ratio R is calculated from the principle of the two-color radiation thermometer disclosed in Patent Document 1, and the measurement is performed based on the relationship between the two-color ratio and the temperature. It becomes possible to measure the temperature of an object more accurately.

Next, we verified how the phenomenon that the effective transmittance of the weighting function on the short wavelength side and the weighting function on the long wavelength side deviate depending on the temperature affects the actual temperature measurement. ..

As the optical characteristics of the weighting function of interest, a weighting function is used in which the weighting coefficient is 1 in the wavelength width range of 60 nm and the weighting coefficient linearly decreases from 1 to 0 in the region having a width of 10 nm at both ends thereof. I made it. Further, the weighting function on the short wavelength side fixed the central transmission wavelength to 1200 nm. Then, at a temperature of 600 ° C., adjustment was performed using the effective transmittance represented by the above formula (2) so that the measured temperature did not change depending on the presence or absence of the water film. In this case, the central transmission wavelength of the weighting function on the long wavelength side is 1287.97 nm as described above.

Here, assuming that the object to be measured at a temperature of 1200 ° C. is measured using the above weighting function, the effective transmittance of the weighting function on the short wavelength side when the thermal radiation light passes through a water film having a thickness of 10 mm. And the effective transmittance of the weighting function on the long wavelength side do not match. As a result, the ratio of the effective transmittance on the short wavelength side and the long wavelength side changes from 1 to 1.0125. This change is equivalent to a change of 1.25% in the value of the two-color ratio R used when calculating the temperature with the two-color radiation thermometer. When the change of the two-color ratio of 1.25% is converted into the amount of temperature change from the relationship between the two-color ratio and the temperature as disclosed in Patent Document 1, a measurement error of 17.5 ° C. is obtained.

From the above verification, when the temperature of the object to be measured can change significantly, a weighting function for measuring the temperature near 600 ° C, a weighting function for measuring the temperature near 800 ° C, and a temperature near 1000 ° C. A weighting function for measuring 1200 ° C., a weighting function for measuring a temperature near 1200 ° C., ... It is preferable to switch so that an appropriate weighting function is selected and set with reference to the temperature of.

More specifically, first, the temperature measuring device of the present embodiment is used to measure the approximate temperature of the object to be measured by using the two-color radiation temperature measurement. At this point, it is not necessary to select the optimum weighting function, and in that respect, it is only necessary that the temperature can be measured with coarse accuracy (for example, measurement of 1200 ° C. with a weighting function suitable for 600 ° C.). If the temperature of the object is measured and there is a water film with a thickness of 10 mm on the optical path, a measurement error of 17.5 ° C. will occur as described above). Then, based on the measured (coarse) temperature, the weighting function according to the closer temperature among the plurality of weighting functions stored in the storage unit (corresponding to the temperature that the object to be measured can take). That is, make sure to select an appropriate weighting function. Then, using the appropriate weighting function, the temperature of the object to be measured is measured by the temperature measuring device of the present embodiment.

In this way, by measuring the approximate temperature in advance, it is possible to select an appropriate weighting function even in an environment where temperature measurement such as the presence of an absorber is not easy. It is possible to measure the temperature of the object to be measured without deteriorating the accuracy. It is difficult to realize such a function with a physical optical filter, and by constructing a spectroluminometer capable of continuously observing an optical spectrum and a weighting function as described above, the above function can be achieved. It will be realized.

In the above description, water has been focused on as an absorber, and a detailed description has been given. However, an absorber other than water (for example, oil, solution, glass, resin, etc.) is placed on the optical path between the object to be measured and the object to be measured. Even if it can exist, it is possible to configure a weighting function in the same manner to deal with it.

Hereinafter, the temperature measuring device and the temperature measuring method according to the embodiment of the present invention obtained based on the above findings will be described in detail.

(Embodiment)
<About the configuration of the temperature measuring device>
In the following, first, 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. 8A and 8B. 8A and 8B 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 absorption coefficient 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 absorption coefficient 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. 8A, 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 radiation light (observation) with respect to a measurement object that emits thermal radiation 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. Measure the magnitude of light). More specifically, the measuring unit 101 is a detector that disperses the incident light for each wavelength, detects the brightness at each wavelength, and outputs the detection result as a spectral brightness signal. Measurement is performed using a spectroscopic brightness meter, and measurement data regarding the spectral brightness signal of thermal radiation is generated.

The measuring unit 101 corresponds to an optical system composed of, for example, various lenses / lens groups in a two-color radiation thermometer, a spectroluminance meter, 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), 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 measures based on the measurement data generated by the measurement unit 101 and the relational expression between the spectral radiance and the temperature derived from Planck's blackbody radiation equation. Calculate the temperature of the object. The information on the temperature of the measurement object 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 stores various parameters and data such as the spectral absorption coefficient of the absorber of interest, the spectral emissivity of the object to be measured, and the weighting function. 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 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 data related to the weighting function as described above. It is preferable that the temperature range in which the weighting function is allowed to be applied is preset in the retained data regarding the individual weighting functions based on the desired temperature measurement accuracy and the like. Further, as the data related to the weighting function, it is preferable that the data related to a plurality of weighting functions is held according to the temperature that the object to be measured of interest can take. The arithmetic processing unit 103 can generate a spectral luminance signal of a desired wavelength based on the spectral luminance signal obtained by the spectroluminance meter by appropriately using the weighting function held in the storage unit 105. Become.

As shown schematically in FIG. 8A, 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. 8B. In the example shown in FIG. 8B, 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. 8B, 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. 9. FIG. 9 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. 9, the measuring unit 101 includes a light receiving unit 111 that receives thermal radiation light from the object to be measured, a detecting unit 113 that detects the thermal radiation light received by the light receiving unit 111, and the like. 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.

The light receiving unit 111 provides thermal radiation light from the measurement target in the case where an absorber such as water having a wavelength dependence on the spectral absorption coefficient in the near infrared band can exist on the optical path to the measurement target. As shown in FIG. 9, 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 are transferred to the optical fiber OF. It has a connection coupler 123 for connecting to. 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. 9, 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 heat radiant light from the measurement object in which the absorbers of various thicknesses (water in FIG. 9) are present on at least a part of the surface is connected by the light receiving lens 121 of the light receiving unit 111 as a substantially parallel luminous flux. Reach the 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.

The detection unit 113 detects the spectral brightness of the heat radiated light of the measurement object received by the light receiving unit 111 as a spectral brightness signal by using a spectroscopic brightness meter, and as illustrated in FIG. 9, the optical fiber OF It has a connection coupler 151 that is optically connected, a condenser lens 153, and a spectroscopic brightness meter 155.

The thermal radiation light from the object to be measured that has passed through the connection coupler 151 is condensed by the condenser lens 153 to the spectroluminance meter 155. The spectroscopic brightness meter 155 disperses the heat radiant light from the incident object to be measured, detects the spectral brightness value for each wavelength, and generates measurement data related to the spectral brightness signal. After that, the spectral luminance meter 155 outputs the measurement data regarding the obtained spectral luminance signal to the arithmetic processing unit 103.

Although the condenser lens 153 is schematically shown in FIG. 9 using one biconvex lens, the condenser lens 153 may be a lens group composed of a plurality of lenses. Further, the lens used for the condenser lens 153 is not particularly limited, and known optical elements such as a spherical lens and an aspherical lens can be appropriately used.

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

The arithmetic processing unit 103 according to the present embodiment obtains the temperature of the measurement object based on the spectral luminance signal of the measurement object detected by the detection unit 113, and as illustrated in FIG. 10, the measurement control unit It mainly includes 171, a data acquisition unit 173, a luminance data generation unit 175, a temperature calculation unit 177, a result output unit 179, and a display control unit 181.

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. The measurement control unit 171 controls the operation of the measurement unit 101 including the spectroluminometer so as to measure the thermal radiation light from the object to be measured. Further, the measurement control unit 171 provides the luminance data generation unit 175 and the temperature calculation unit 177 with various information such as measurement conditions for thermal radiation and information for designating the type of weighting function to be used, as necessary. It is also possible to output the set value of.

Further, the measurement control unit 171 refers to the information regarding the temperature measurement result of the measurement object calculated from the temperature calculation unit 177, and the calculated temperature of the measurement object is allowed in the weighting function currently used. It may be determined whether it belongs to the temperature range. At this time, if the calculated temperature of the measurement object does not belong to the temperature range allowed by the currently set weighting function, the measurement control unit 171 sets the calculated temperature of the measurement object to the calculated temperature. It is preferable to set another suitable weighting function. Then, the measurement control unit 171 causes the luminance data generation unit 175 to re-execute the luminance data generation process described later by using another weighting function set, and causes the temperature calculation unit 177 to perform the luminance data generation process again. The temperature calculation process is performed again. As a result, the temperature measuring device 10 according to the present embodiment can measure the temperature of the object to be measured more accurately.

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 data of the spectral luminance signal generated by the measurement unit 101 and outputs the data to the luminance data generation unit 175, which will be described later. Further, the data acquisition unit 173 may associate the acquired spectral luminance signal data with time information related to the date and time when the spectral luminance signal data was acquired and store it in the storage unit 105 as history information.

The luminance data generation unit 175 is realized by, for example, a CPU, a ROM, a RAM, or the like. In explaining the function of the brightness data generation unit 175, in the following, a band having a predetermined wavelength width including one of two types of wavelengths in which the spectral absorption coefficients (or spectral transmittances) of the absorbers are the same as each other. Is referred to as a first wavelength band, and a band having a predetermined wavelength width including the other wavelength is referred to as a second wavelength band.

The brightness data generation unit 175 refers to the data of the spectral brightness signal output from the data acquisition unit 173, and obtains the measurement data of the spectral brightness signal in the first wavelength band and the measurement data of the spectral brightness signal in the second wavelength band. , Is extracted. After that, the brightness data generation unit 175 uses the data related to the weighting function as described above, which is preset by the measurement control unit 171, to obtain the measurement data in the first wavelength band and the measurement data in the second wavelength band, respectively. Are weighted and added up. As a result, the luminance data generation unit 175 generates the first luminance data which is the luminance data of the spectral radiance about the first wavelength band and the second luminance data which is the luminance data of the spectral radiance about the second wavelength band. do. The two types of luminance data generated in this way correspond to the luminance signals of thermal radiation light at two kinds of wavelengths in which the spectral absorption coefficients (or spectral transmittances) of the absorbers are the same as each other.

When the luminance data generation unit 175 generates the first luminance data and the second luminance data, the generated luminance data is output to the temperature calculation unit 177, which will be described later.

The temperature calculation unit 177 is realized by, for example, a CPU, a ROM, a RAM, or the like. The temperature calculation unit 177 uses two types of luminance data (first luminance data and second luminance data) output from the luminance data generation unit 175 to convert the luminance signal in one luminance data into the luminance in the other luminance data. The two-color ratio (in other words, the ratio of spectral radiance) divided by the signal is calculated. Further, the temperature calculation unit 177 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 (11) and (12), 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 (13) when the formula is derived in the same manner as in Patent Document 1 by using the following formulas (11) and (12).

Here, in the above equations (11) and (12), 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 brightness data generation unit 175 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 Data processing is performed using a weighting function so that brightness signals having wavelengths in which) are the same as each other can be obtained. Therefore, the terms related to absorption by the absorber shown in the first term on the middle side of the above formula (13) 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 (13) are as shown in the following equations (14a) and (14b).

_{Here, R λ} and Λ shown in the equations (14a) and (14b) are determined from the central transmission wavelength defined by the set of weighting functions (weighting functions on the short wavelength side and the long wavelength side) used. It becomes a constant. Therefore, the temperature calculation unit 177 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 (13). It will be possible.

When the temperature calculation unit 177 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 177 may directly calculate the temperature by using the above formulas (11) and (12) without using the two-color ratio R represented by the above formula (13). 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 (11) and (12) are the temperature T and the thickness t of the water film. Therefore, the temperature calculation unit 177 can calculate the temperature T by simultaneously obtaining the solutions of the simultaneous equations by combining the above equations (11) and (12). 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 (11) and the equation (12). 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 177 outputs the information regarding the temperature T of the measurement object calculated as described above to the measurement control unit 171 and the result output unit 179, which will be described later, respectively.

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 177 to the user of the temperature measuring device 10. Specifically, the result output unit 179 associates the data corresponding to the temperature measurement result with the time data related to the date and time when the data was generated, outputs the data to various servers and control devices, and outputs the data to a printer or the like. The device is used to output as a paper medium. Further, the result output unit 179 may output the data corresponding to the measurement 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 179 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 179 outputs the data. , The measurement 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 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 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. 8A to 10.

<About temperature measurement method>
Next, 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 measurement method 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 provided with the spectral brightness meter measures the thermal synchrotron radiation from the object to be measured (step). S101). As a result, the thermal radiant light from the object to be measured is detected while being separated, and measurement data regarding the spectral luminance signal is generated. The measurement data related to the generated spectral luminance signal is output to the data acquisition unit 173 of the arithmetic processing unit 103.

The data acquisition unit 173 of the arithmetic processing unit 103 outputs the measurement data related to the spectral luminance signal output from the measurement unit 101 to the luminance data generation unit 175.

The brightness data generation unit 175 uses two types of brightness data (that is, the first) using the measurement data related to the spectral brightness signal output from the data acquisition unit 173 and the weighting function set in advance by the measurement control unit 171. The brightness data and the second brightness data) are generated (step S103). When the luminance data generation unit 175 generates two types of luminance data, the luminance data generation unit 175 outputs the generated two types of luminance data to the temperature calculation unit 177.

The temperature calculation unit 177 calculates the two-color ratio R using the two types of generated luminance data (first luminance data and second luminance data) (step S105). After that, the temperature calculation unit 177 calculates 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 S107). The temperature calculation unit 177 outputs the obtained information on the temperature of the measurement object to the measurement control unit 171 and the result output unit 179.

The measurement control unit 171 determines whether or not the calculated temperature is within the allowable temperature range set in the weighting function used (step S109). If the calculated temperature is not within the permissible temperature range (step S109-NO), the measurement control unit 171 changes the weighting function to one suitable for the calculated temperature (step S111), and proceeds to step S103. Go back and continue processing.

On the other hand, when the calculated temperature is within the permissible temperature range (step S109-YES), the result output unit 179 outputs the temperature of the measurement object calculated by the temperature calculation unit 177 as the measurement result. (Step S113).

As a result, in the temperature measuring method according to the present embodiment, it is possible to measure the temperature of the object to be measured while further suppressing the temperature measurement error.

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 Condensing lens 155 Spectral brightness meter 171 Measurement control unit 173 Data acquisition unit 175 Brightness data generation unit 177 Temperature calculation unit 179 Result output unit 171 Display control unit

Claims (5)

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.
A detection unit that detects the spectral luminance of the thermal radiant light received by the light receiving unit as a spectral luminance signal using a spectral luminance meter.
An arithmetic processing unit that obtains the temperature of the object to be measured based on the spectral luminance signals corresponding to the two wavelengths of the absorber that have the same spectral transmittance detected by the detection unit.
Have,
The arithmetic processing unit
Set a weighting function consisting of consecutive dimensionless numbers in the wavelength direction,
A temperature measuring device that obtains the temperature of the object to be measured based on the weighting function, the value of the spectral transmittance of the spectral luminance meter, and the spectral luminance signal. The storage unit stores a plurality of weighting functions according to the temperature of the measurement object.
The arithmetic processing unit
Using the temperature measuring device, the approximate temperature of the object to be measured is measured.
The temperature measuring device according to claim 1, wherein an optimum weighting function is selected and set from a plurality of weighting functions stored in the storage unit based on the obtained temperature. The arithmetic processing unit
At one of the two wavelengths having the same spectral transmittance of the absorber, the position of the weighting function in the wavelength direction is set to the position of the one wavelength, and then the spectral transmittance of the spectrophotometer. The first weighted data is calculated by multiplying the rate value by the weighting function and adding them up.
At the other wavelength of the two wavelengths having the same spectral transmittance of the absorber, the position of the weighting function in the wavelength direction is set to a predetermined position near the other wavelength, and then the spectral brightness. The second weighted data is calculated by multiplying the spectral transmittance value of the meter by the weighting function and adding them up.
While moving the predetermined position in the wavelength direction, the first weighted data and the second weighted data are compared, and the first weighted data and the second weighted data have the same value. Determine the given position and
The position of the weighting function in the wavelength direction is set to the position of one of the wavelengths, and the value obtained by multiplying the weighting function by the spectral brightness signal and the predetermined position where the position of the weighting function in the wavelength direction is determined. The temperature measuring device according to claim 1 or 2, wherein the weighting function is set to, and the temperature of the measurement object is obtained from the ratio to the value obtained by multiplying the spectral brightness signal. The temperature measuring device according to any one of claims 1 to 3, wherein the absorber is at least one of water, fat, solution, glass or 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.
A detection step of detecting the spectral luminance of the thermal radiant light received in the light receiving step as a spectral luminance signal using a spectral luminance meter, and a detection step.
An arithmetic processing step of obtaining the temperature of the object to be measured based on the spectral luminance signals corresponding to the two wavelengths of the absorber having the same spectral transmittance detected in the detection step.
Have,
The arithmetic processing step is
Set a weighting coefficient consisting of dimensionless numbers that are continuous in the wavelength direction,
A temperature measuring method for determining the temperature of an object to be measured based on the weighting coefficient, the value of the spectral transmittance of the spectral luminance meter, and the spectral luminance signal.

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