Temperature measuring device and temperature measurement method, and program

Abstract

To provide a temperature measuring device and a temperature measurement method, and a program allowing the wavelength of light used for measuring temperature of an object to be examined to have a degree of freedom.SOLUTION: The temperature of an object to be examined not affected by the amount of presence of an absorber is specified from a ratio of sensor light reception intensity when the absorber does not exist at one or the other of two proximal wavelengths in a two-color temperature measurement method on the basis of first light intensity information received for each multiple known presence amounts as the amount of presence of the absorber, second light intensity information regarding first light received when the absorber exists with an actual presence amount regarding spectral radiation energy of an object to be examined, and third light intensity information regarding second light so as to include two proximal wavelengths, the wavelength of first light included in a first wavelength range with the center wavelength ranging from 900 nm to 1000 nm, and the wavelength of second light included in another wavelength range regarding spectral radiation energy of a reference light source in which temperature is known.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a temperature measurement device, a temperature measurement method, and a program that can accurately measure the temperature of a test object even when an absorber is present on the test object or in the light receiving optical path from the test object when measuring the temperature of the test object.

Background Art

[0002] As a temperature measurement device for measuring the temperature of a test object, a two-color thermometer that converts temperature from the ratio of radiance using two different wavelengths close to each other based on the two-color temperature measurement method can measure the temperature of the test object non-contact, and thus is applied in various fields. Also, a two-color temperature camera that uses a two-dimensional sensor in the detection unit using the measurement principle of the two-color thermometer is known as a temperature measurement device that can measure the temperature distribution of a test object non-contact.

[0003] Here, when a substance that absorbs light such as water or water vapor exists in the optical path, generally, it is difficult to measure with a two-color thermometer or a two-color temperature camera. For example, Patent Document 1 discloses a temperature measurement technique using two wavelengths with the same spectral absorption coefficient as two wavelengths.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, there are restrictions on the wavelengths of light used for measuring the temperature of the test object, and it has been desired to have freedom in the wavelengths of light used for measuring the temperature of the test object.

[0006] An object of the present invention is to provide a temperature measurement device, a temperature measurement method, and a program that can give freedom to the wavelength of light used for temperature measurement of a test object.

Means for Solving the Problems

[0007] To achieve the above object, a temperature measurement device according to the present invention is a temperature measurement device that measures the temperature of a test object based on the ratio of the light intensities when receiving the radiation energies for two wavelengths close to each other with respect to the spectral radiation energy of the test object, and has a correction unit that uses a measured value affected by the abundance of an absorber present on the test object or in the optical path from the test object as the original measured value not affected by the abundance of the absorber. The correction unit uses light included in a first wavelength range with a central wavelength between 900 nm and 1000 nm, which is light with a wavelength at which the change in light intensity when received according to the abundance of the absorber is large and which is absorbed by the absorber, as the first light, and uses, as the second light, light included in at least one of a second wavelength range with a central wavelength between 650 nm and 900 nm, a third wavelength range with a central wavelength between 1000 nm and 1080 nm, and a fourth wavelength range with a central wavelength between 1220 nm and 1290 nm, which is light with a wavelength at which the absorption by the absorber is small and the change in light intensity when received according to the abundance of the absorber is small. Regarding the spectral radiation energy of a reference light source with a known temperature, light intensity information received for each of a plurality of known abundances as the abundance of the absorber so as to include the two close wavelengths, the wavelength of the first light, and the wavelength of the second light is used as the first light intensity information. Regarding the spectral radiation energy of the test object, light intensity information received when the absorber exists in the existing abundance for the wavelength of the first light is used as the second light intensity information, and regarding the spectral radiation energy of the test object, light intensity information received when the absorber exists in the existing abundance for the wavelength of the second light is used as the third light intensity information. Then, based on the first light intensity information, the second light intensity information, and the third light intensity information, the received light intensities when the absorber does not exist are respectively specified for one and the other of the two close wavelengths, and the temperature of the test object is specified based on the ratio of the specified light intensities.

[0008] In addition, the temperature measurement method according to the present invention is a temperature measurement method for measuring the temperature of a test object based on the ratio of the light intensities when receiving the radiation energies for two wavelengths close to each other with respect to the spectral radiation energy of the test object, and has a correction step of using a measured value affected by the abundance of an absorber present on the test object or in the optical path from the test object as the original measured value not affected by the abundance of the absorber. In the correction step, light included in a first wavelength range having a center wavelength between 900 nm and 1000 nm, which is light having a wavelength at which the change in the light intensity when received according to the abundance is large and which is absorbed by the absorber, is defined as first light, For the first light, light included in at least one of a second wavelength range having a center wavelength between 650 nm and 900 nm, a third wavelength range having a center wavelength between 1000 nm and 1080 nm, and a fourth wavelength range having a center wavelength between 1220 nm and 1290 nm, which is light having a wavelength at which the absorption by the absorber is small and the change in the light intensity when received according to the abundance of the absorber is small, is defined as second light. With respect to the spectral radiation energy of a reference light source with a known temperature, light intensity information received for each of a plurality of known abundances as the abundance of the absorber so as to include the two close wavelengths, the wavelength of the first light, and the wavelength of the second light is defined as first light intensity information. With respect to the spectral radiation energy of the test object, light intensity information received when the absorber exists in the existing abundance for the wavelength of the first light is defined as second light intensity information. When light intensity information received when the absorber exists in the existing abundance for the wavelength of the second light is defined as third light intensity information with respect to the spectral radiation energy of the test object, the received light intensities when the absorber does not exist at one and the other of the two close wavelengths are respectively specified based on the first light intensity information, the second light intensity information, and the third light intensity information, and the temperature of the test object is specified based on the ratio of the specified light intensities.

[0009] The present invention is also configured as a program for causing a computer to function as each means of the temperature measurement device.

Advantages of the Invention

[0010] The present invention can provide freedom in the wavelength of light used for measuring the temperature of a test object. Thereby, even when using light of wavelengths with different spectral absorption coefficients, it is possible to avoid the measured value being affected by the presence of an absorber existing on the test object or in the optical path from the test object.

Brief Description of the Drawings

[0011]

Figure 1

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be implemented in many different modes and should not be construed as being limited to the description content of the present embodiments. Note that the same elements throughout the embodiments will be given the same reference numerals.

[0013] (First Embodiment) Prior to the specific description of this embodiment, first, the two-color thermometer method will be described.

[0014] (Two-color Thermometry) The concept of two-color thermometry will be described below. To measure the temperature of a high-temperature workpiece above 300°C non-contact, the electromagnetic radiation emitted from the measurement target is measured, and the temperature is calculated from its intensity. As products based on this principle, there are radiation thermometers that obtain temperature from visible light or infrared light, and thermography for measuring temperature distribution. Since a general measurement target is a non-blackbody, to obtain the true temperature from a radiation thermometer or thermography, correction must be made using the emissivity, which is the ratio of the radiation amount to that of a blackbody. However, since the emissivity of a non-blackbody generally varies depending on its material, shape, and temperature, it is difficult to obtain an accurate temperature.

[0015] Therefore, two-color thermometry is used. Two-color thermometry focuses on the fact that the emissivities of radiation at two adjacent wavelengths are the same, and since the ratio of the radiation amounts at the two wavelengths has a functional relationship with the true temperature, the radiation amounts at the two wavelengths are measured and the true temperature is calculated. Explaining using mathematical formulas, it is as follows.

[0016] The radiation utilization at wavelength λ is obtained from Planck's radiation formula.

[0017]

Equation

[0018] When the emissivity of the object is ε and the transmittance from the object to the measurement system is τ, it is shown below.

[0019]

Equation

[0020] Applying Wien's approximation formula, when the radiation energies at two wavelengths λ1 and λ2 are M1 and M2, the emissivities are ε1 and ε2, the transmittances are τ1 and τ2, and the conversion efficiencies of sensors, etc. are β1 and β2, the two-wavelength ratio R at wavelengths λ1 and λ2 is as follows.

[0021] [Number]

[0022] Here, if logarithms are taken, it can be expressed by the following formula.

[0023] [Number]

[0024] When there is no absorber (such as water, water vapor or steam, or a mixture mainly composed of water vapor) on or in the optical path from the object under test, the following holds.

[0025] That is, by making the two wavelengths for radiation acquisition close to each other, the emissivities ε1 = ε2, the transmittances τ1 = τ2, and the conversion efficiencies β1 = β2, and the emissivity ε, the transmittance τ, and the conversion efficiency β are eliminated, and it is known that the ratio of the radiation amounts is in a functional relationship with the temperature.

[0026] [Number]

[0027] Even when the emissivities at two wavelengths and the transmittances of the intervening substances are different, if the ratio does not change with temperature, the true temperature of an object whose temperature changes can be known by correcting the ratio with that of a black body.

[0028] However, when there is an absorber (such as water, water vapor or steam, or a mixture mainly composed of water vapor) on or in the optical path from the object under test, even if the emissivities ε1 = ε2 and β1 = β2, τ1 = τ2 does not hold. The sensor light-receiving intensities at two wavelengths λ1 and λ2 are different, and moreover, they are different depending on the abundance of the absorber.

[0029] (Temperature measurement device and temperature measurement method) In this embodiment, the temperature measurement method will be mainly described. As is obvious to those skilled in the art, as a temperature measurement device, an embodiment having a branched optical system and a structure of a plurality of two-dimensional image sensors using the two-color temperature measurement method can be adopted. In this case, it is premised that the pixel positions of the plurality of two-dimensional image sensors match.

[0030] The temperature measurement device according to this embodiment includes a spectroscopic optical system, a measurement unit including a two-dimensional image sensor having sensitivity in the near-infrared region, and a correction unit that performs sensor output processing.

[0031] (Correction unit) The correction unit in this embodiment uses a measured value affected by the abundance of an absorber present on the object under test or in the optical path from the object under test as the original measured value not affected by the abundance of the absorber. This will be specifically described below.

[0032] (1) Identification of the abundance of the absorber In this embodiment, the light intensities of wavelengths that absorb water or water vapor as the absorber and wavelengths with little absorption (wavelengths corresponding to the background) are used to obtain a value corresponding to the abundance of water or water vapor. As the wavelength that absorbs water or water vapor, at least one wavelength included in the range of 900 nm to 1000 nm is used. Also, as the wavelength with little absorption of water or water vapor, at least one wavelength included in the range of 650 nm to 900 nm or the range of 1000 nm to 1080 nm is used.

[0033] Here, the first light intensity information, the second light intensity information, the third light intensity information, and the divisional relationship are defined as follows together with the first light, the second light, the first wavelength range, the second wavelength range, and the third wavelength range.

[0034] The light included in the first wavelength range with a central wavelength between 900 nm and 1000 nm, which is the light absorbed by the absorber and the change in the sensor light reception intensity is large according to its abundance, is defined as the first light. The first wavelength range is a wavelength range centered on 950 nm, and 950 nm corresponds to the wavelength at which the third harmonic absorption of water and water vapor (described in detail later) appears.

[0035] Then, for the first light, the light included in the second wavelength range with a central wavelength between 650 nm and 900 nm or the third wavelength range with a central wavelength between 1000 nm and 1080 nm, which is the light with little absorption by the absorber and the change in the sensor light reception intensity is small according to the abundance of the absorber, is defined as the second light.

[0036] And, for the spectral radiant energy of a reference light source with a known temperature, the light intensity information received for each of a plurality of known abundances as the abundance of the absorber is defined as the first light intensity information so as to include two wavelengths close to each other for temperature measurement, the wavelength of the first light, and the wavelength of the second light. Also, for the spectral radiant energy of the object under test, the light intensity information received when the absorber exists in the existing abundance for the wavelength of the first light is defined as the second light intensity information. Also, for the spectral radiant energy of the object under test, the light intensity information received when the absorber exists in the existing abundance for the wavelength of the second light is defined as the third light intensity information.

[0037] Also, the divisional relationship relates to the ratio or proportion of the second light intensity information to the third light intensity information with a small change in the sensor light reception intensity according to the abundance of the absorber.

[0038] In this embodiment, the light with a wavelength that absorbs water and water vapor (the first light in the first wavelength range) and the light with a wavelength with little absorption (the second light in the second wavelength range or the third wavelength range) are used to specify the abundance of water and water vapor as the absorber existing between the temperature measuring device and the object under test.

[0039] FIG. 2 is a diagram showing the absorption spectra of water and water vapor. The central wavelengths λ1 and λ2 are wavelengths with little light absorption by water and water vapor, the wavelength λ3 is a wavelength with a large amount of light absorption by water and water vapor, λ4 is a wavelength with little light absorption by water and water vapor, and λ5 is a wavelength with little light absorption by water vapor. Specifically, the wavelengths λ1, λ2, λ3, λ4, and λ5 are 670 nm, 870 nm, 950 nm, 1040 nm, and 1250 nm in order.

[0040] In the following embodiments, four wavelengths are used. The cases of using λ1, λ2, λ3, and λ4 (FIGS. 3 to 11) and the cases of using the wavelengths λ2, λ3, λ4, and λ5 (FIGS. 12 and 13) will be described in order. Here, the absorber in the case of using λ1, λ2, λ3, and λ4 (FIGS. 3 to 11) may be either water or water vapor, and when both are present, for example, it may be a case where water vapor, steam, and water adhering to the object to be inspected coexist.

[0041] Also, the absorber in the case of using the wavelengths λ2, λ3, λ4, and λ5 (FIGS. 12 and 13) is assumed to be only water vapor, or a case where water vapor is the main component and a small amount of steam or water is mixed. Specifically, when 90% or more of the absorber is water vapor, the wavelengths λ2, λ3, λ4, and λ5 can be used.

[0042] FIG. 3 is a diagram showing the light intensity distribution after light radiated from a reference light source at about 1500 °C passes through the optical path when there is no water vapor as an absorber in the optical path, when water vapor is present at a low concentration, and when water vapor is present at a medium concentration. FIG. 4 is a diagram obtained by adding a measurement example of the sensor light reception intensity at the wavelengths λ1 to λ4 when the object to be inspected is the measurement target to FIG. 3. FIG. 5 is a diagram for explaining specifying a reference light source of a provisional temperature from the sensor light reception intensities at λ1, λ2, and λ4. FIG. 6 is a diagram obtained by obtaining a corrected intensity distribution in consideration of the amount of water vapor and adding this to FIG. 5.

[0043] In Fig. 5, a reference light source for the provisional temperature is specified from the sensor light reception intensities at wavelengths λ1, λ2, and λ4 with low absorption. To specify the abundance of the absorber, two wavelengths of λ2 and λ3, or two wavelengths of λ3 and λ4 can be used. The abundance of the absorber is specified as shown in Fig. 8. That is, for example, using two wavelengths of λ2 and λ3, for the ratio X = sensor light reception intensity at λ3 / sensor light reception intensity at λ2, the consistency with the previously measured ratio A in the reference light source is confirmed. When the ratio X is equal to Ai, the abundance of the absorber is specified as Bi. When the ratio X is between Ai and Ai+1, the abundance of the absorber is estimated by interpolation (a value obtained by interpolation with a value between Bi and Bi+1).

[0044] Fig. 7 is a figure in which the specification of the reference light source for the provisional temperature and the calculation of the correction by the water vapor amount are performed multiple times, and then the obtained corrected intensity distribution is added to Fig. 5. As shown in Fig. 7, the corrected intensity distribution after multiple corrections is obtained as being close to the sensor light reception intensity of the reference light source without the absorber, and the light reception intensities without water vapor (true intensity distribution) at two adjacent wavelengths (for example, λ1 and λ2) of the two-color thermometer measurement method can be specified.

[0045] The consistency between the ratio of the light reception intensities without water vapor (true intensity distribution) at λ1 and λ2 and the previously measured luminance ratio of the blackbody is confirmed, and the temperature of the blackbody is taken as the temperature of the object under test.

[0046] Fig. 9 is a figure showing the light intensity distribution after the light radiated from a reference light source of about 500 °C passes through the optical path when there is no water vapor as an absorber in the optical path, when there is water vapor present at a low concentration, and when there is water vapor present at a medium concentration. Fig. 10 is a figure in which a measurement example of the sensor light reception intensities at wavelengths λ1 to λ4 when the object under test is the measurement target is added to Fig. 9. Also in this case, the light reception intensity without water vapor (true intensity distribution) can be specified by the same method as described above.

[0047] (Type of absorber) As the absorber, typically, water, water vapor or steam, or a mixture mainly composed of water vapor can be considered. FIG. 11 shows the light intensity distribution after light radiated from a reference light source at about 1500° C. passes through the optical path in the cases where there is no water vapor as the absorber in the optical path, where only water vapor exists, and where water vapor mixed with industrial oil exists. Industrial oil is mainly composed of hydrocarbons and is known to exhibit absorption around 920 nm to 930 nm and around 1010 nm to 1030 nm, and FIG. 11 shows the light intensity distribution reflecting this. FIG. 11 indicates that knowledge about whether industrial oil is mixed can potentially be obtained by analyzing in detail the light intensities at λ2 to λ4.

[0048] (Wavelength used) It is the wavelength to be used. There are a wavelength P used to specify the abundance as the absorber and a wavelength Q used to measure the temperature of the object under test by the two-color thermometer method.

[0049] In FIG. 8 described above, it is shown that wavelengths λ2 and λ3 are used as the wavelength P, and wavelengths λ1 and λ2 can be used as the wavelength Q. However, the present invention is not limited to this.

[0050] 1) Wavelength P (wavelength for specifying the abundance as the absorber) In FIGS. 3 to 11 as an example using four wavelengths λ1 to λ4 as a whole, as the wavelength P, wavelengths λ2 and λ3, or wavelengths λ4 and λ3 can be used.

[0051] Also, as the wavelength P, three wavelengths of the central wavelengths λ2, λ3, and λ4 can be utilized. The central wavelengths λ2, λ3, and λ4 are 870 nm, 950 nm, and 1040 nm in order, and the bandwidth is 25 nm. However, the central wavelength and the bandwidth can be changed as long as they conform to the technical idea of the present invention. When the absorption of water or water vapor is large (when there is a lot of water or water vapor in the optical path), for example, the bandwidth of λ3 can be widened.

[0052] Regarding the identification of the amount of water and water vapor present in the optical path, although it has been mainly described that the sensor light reception intensity ratio of λ2 and λ3 is used, instead of this, the amount of the above-mentioned water and water vapor can also be identified from the sensor intensities of three wavelengths of the central wavelengths λ2, λ3, and λ4.

[0053] In advance, standard data is obtained using a reference light source with a known temperature in an experimental system where the amount of water and water vapor in the optical path is controlled, and the abundance of water and water vapor is preferably identified in a form of comparing with this. This standard data is obtained by photographing a reference light source (temperature standard) with a known temperature through water and / or water vapor with a known abundance in advance. That is, the temperature range to be measured is photographed at intervals, and the abundance of water or water vapor is also photographed at intervals.

[0054] In the present invention, as the four wavelengths, instead of the wavelengths λ1 to λ4 shown in FIGS. 3 to 11, wavelengths λ2 to λ5 can also be used as shown in FIGS. 12 and 13. λ5 is a wavelength in the wavelength range of 1220 nm to 1290 nm, and 1250 nm can be cited as an example of the central wavelength. In this case, as the wavelengths P to be used, three wavelengths of the central wavelengths λ2, λ3, and λ4 can also be used in the same manner as described above. The central wavelengths λ2, λ3, and λ4 are 870 nm, 950 nm, and 1040 nm in order, and the bandwidth is 25 nm, but the central wavelength and the bandwidth can be changed as long as they conform to the technical idea of the present invention. When the absorption of water and water vapor is large (when there is a lot of water and water vapor in the optical path), for example, the bandwidth of λ3 can be widened.

[0055] Also, as the wavelengths P to be used, at least one wavelength among the central wavelengths λ2, λ4, and λ5 and the wavelength of the central wavelength λ3 can be used.

[0056] 2) Wavelengths P to be used (wavelengths for measuring the temperature of the object to be measured by two-color thermometry) When using four wavelengths in total, when using the wavelengths λ1 to λ4 shown in FIGS. 3 to 11, for the used wavelength Q, for temperature measurement at a high temperature of 1000 °C or higher, two wavelengths of 900 nm or less (λ1 and λ2) can be used, and at least one wavelength exceeding 1000 nm can be used for temperature measurement in the range of 500 °C to 1200 °C (for example, λ4 and λ2).

[0057] Also, when using the wavelengths λ2 to λ5 as the four wavelengths as shown in FIGS. 12 and 13, λ4 and λ5 can be used for temperature measurement in the range of 300 °C to 1000 °C.

[0058] In addition, the three wavelengths of λ1, λ2, and λ4 in the embodiment shown in FIGS. 3 to 11, and the three wavelengths of λ2, λ4, and λ5 in the embodiment shown in FIGS. 12 and 13 are also the background wavelengths for estimating the amount of water and water vapor. It is possible to use the same wavelength for the wavelength used for temperature measurement and the background wavelength used for obtaining the value corresponding to the abundance of water and water vapor. By using the same wavelength, the number of wavelengths used can be reduced, and the measurement and analysis load can be reduced.

[0059] In addition, if the exposure time of the sensor can be changed for each of the above wavelengths, that method can also be used. However, generally, the measurement object often has temporal fluctuations, and in that case, the method of changing the exposure time is not preferable. This also means that a time-division spectrometer or a time-division hyperspectral camera is not suitable for the four-color measurement shown in FIG. 12.

[0060] (Third overtone absorption wavelength of water and water vapor) It is known that water and water vapor exhibit main absorption near a wavelength of 3 μm, its overtone absorption appears near a wavelength of 1.95 μm, the second overtone absorption appears near a wavelength of 1.45 μm, and the third overtone absorption appears near a wavelength of 0.95 μm as shown in FIG. 2. The absorption intensity decreases as the wavelength becomes shorter, and there is a difference of about three orders of magnitude between the main absorption and the third overtone absorption.

[0061] In the region where the wavelength is longer than 1.1 μm, for various reasons, water absorption appears to a certain extent at any wavelength range. And the absorption peak wavelengths of water and water vapor are not the same. Regarding the third harmonic absorption, water is about 0.96 μm (960 nm), while water vapor is about 0.94 μm (940 nm).

[0062] The third harmonic absorption of water and water vapor is relatively small, but on the other hand, this wavelength can also be said to be suitable for specifying the amount of water and water vapor present in the optical path. The reasons are shown below.

[0063] The first reason is that there is a background wavelength near the above-mentioned third harmonic absorption where the absorption of water and water vapor is small and this can be utilized.

[0064] For temperature measurement using the two-color thermometer method, it is common to use "two wavelengths with a wavelength difference of about 200 nm" that can cancel the influence of emissivity. The second reason is that if the above-mentioned background wavelength where the absorption of water and water vapor is small is used, a wide temperature range from about 300 °C to about 2500 °C can be measured. Note that light scattering increases as the wavelength becomes shorter, but if the wavelength difference is about 200 nm to 400 nm, the influence is minor.

[0065] Also, when using a two-dimensional sensor in the measurement section, if the wavelength range from 650 nm to 1290 nm is the target, for example, general-purpose sensors such as black silicon can be used, and general-purpose lenses with small chromatic aberration and distortion can also be used. This is also the reason for targeting the vicinity of the third harmonic absorption of the above-mentioned water and water vapor. In particular, for obtaining a temperature distribution image with high spatial resolution, in combination with the prism spectroscopic optical system described later, the selection of the above-mentioned sensors and lenses is also important.

[0066] (Spectroscopic optical system) To improve the accuracy of temperature measurement and obtain a temperature distribution image with high spatial resolution, it is preferable to use prism spectroscopy and a plurality of two-dimensional sensors. An example of a spectroscopic optical system when detecting four colors shown in FIG. 4 with a two-dimensional sensor is shown in FIG. 12.

[0067] The combined prism in the spectroscopic optical system shown in Fig. 14 is formed by combining a plurality of prism units, and an optical thin film is formed on the bonding surface. In the optical thin film, the ratio of transmitted light (T) to reflected light (R) is 1:1. A general thin film used in a beam splitter can be used for this optical thin film. It is a common configuration to install an objective lens or relay lens on the incident side of this prism and a relay lens and a two-dimensional sensor on the exit side.

[0068] As the material of the prism, it is common to use synthetic quartz with high transmission characteristics, but it is not limited to this, and any material that can obtain certain transmission characteristics in the wavelength range of 650 nm to 1290 nm can be used.

[0069] (Sensor) As described above, when using a two-dimensional image sensor in the measurement unit, if the wavelength range from 650 nm to 1290 nm shown in Fig. 4 is the target, a general-purpose sensor such as black silicon can be used. In this embodiment, by using a two-dimensional image sensor, the panoramic view of the object to be inspected can be grasped non-contact, and by adopting the two-color temperature measurement method, emissivity correction is not required and temperature measurement of all pixels or a plurality of measurement points can be performed.

[0070] The above is an overview of the first embodiment of the present invention regarding two-color temperature measurement using two adjacent wavelengths λ1 and λ2, obtaining the temperature not affected by the absorber by using the intensity ratio of wavelength λ2 to wavelength λ3 for the abundance of the absorber, as follows.

[0071] 1) Temperature measurement of the object to be inspected by two-color temperature measurement method using two adjacent wavelengths λ1 and λ2 When the luminance of the object to be inspected at wavelength λ1 is R1 and the luminance at wavelength λ2 is R2, the luminance ratio Y = R1 / R2 of the object to be inspected is obtained. Then, the blackbody temperature that matches the previously measured blackbody luminance ratio is taken as the temperature of the object to be inspected.

[0072] Incidentally, when there is no absorber between the object under test and the sensor, Y = R1 / R2 = V1 / V2. Here, V1 is the sensor light reception intensity at wavelength λ1 with respect to the object under test, and V2 is the sensor light reception intensity at wavelength λ2 with respect to the object under test.

[0073] 2) Identification of the abundance of the absorber Here, when there is an absorber in the optical path from the object under test to the sensor, after identifying the reference light source S for its abundance, it is identified using the ratio X = V3 / V2. Here, V3 is the sensor light reception intensity at wavelength λ3 with respect to the object under test, and V2 is the sensor light reception intensity at wavelength λ2 with respect to the object under test.

[0074] 3) Identifying the temperature not affected by the absorber from the ratio of the correction intensities at two adjacent wavelengths (for example, λ1, λ2) when the absorber is absent When the reference light source S and the abundance of the absorber are identified, from the sensor light reception intensity distribution (curve) obtained separately in advance according to the abundance, the ratio of the correction intensities at two adjacent wavelengths (for example, λ1, λ2) can be identified. Then, the temperature of the blackbody that matches the luminance ratio of the blackbody measured in advance is taken as the temperature of the object under test.

[0075] (Second Embodiment) In the first embodiment, the ratio of the sensor light reception intensities at two adjacent wavelengths used in the two-color temperature measurement method is identified based on the division relationship between the first light intensity information, the second light intensity information, and the third light intensity information. However, in this embodiment, based on the addition relationship between the first light intensity information, the second light intensity information, and the third light intensity information, the ratio of the sensor light reception intensities at two adjacent wavelengths used in the two-color temperature measurement method is identified.

[0076] The addition relationship means combining (connecting) the second light intensity information and the third light intensity information so that the similarity with the first light intensity information can be determined.

[0077] In the present embodiment, the relative values of the light intensities of each wavelength λ1 to λ3 normalized by the light intensity of λ4 are taken on the vertical axis, the relative values are plotted at each wavelength λ1 to λ4, and the shape of the envelope connecting the four plotted positions is determined. And the shape of a known envelope connecting the four plotted positions stored in advance corresponding to each reference temperature and each abundance of the absorber is determined for consistency (pattern matching).

[0078] In the present embodiment, based on pattern matching, the abundance of the absorber and the temperature of the object to be inspected can be specified simultaneously.

[0079] FIG. 1 shows a flowchart according to the present invention common to the first and second embodiments. In step S1, temperature measurement is performed based on the ratio of the sensor light reception intensities at two adjacent wavelengths. In step S2, the first light intensity information when the reference light source is the measurement target in the presence of the absorber is stored. In step S3, the second and third light intensity information when the object to be inspected is the measurement target in the presence of the absorber is acquired. Then, in step S4, the temperature is specified based on the ratio of the corrected sensor light reception intensities at two adjacent wavelengths.

[0080] As described above, according to the present invention, unlike those with restrictions on the wavelengths used as in Patent Document 1, it is possible to have freedom in the wavelengths used. Then, by processing with the two-color thermometer method, high-precision temperature data can be obtained, and by measuring the temperature of the product during processing or heat treatment through water or steam, it is possible to manufacture products with stable quality. It also contributes to cost reduction and energy saving, such as reducing defective products and wasteful heating.

[0081] (Modification example) Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof. For example, it is also possible to combine the first embodiment and the second embodiment. Further, the number of wavelengths used is not limited to four, and for example, five wavelengths of λ1 to λ5 can also be used. In this case, a five-branch optical system as shown in FIG. 15 can be used.

[0082] In addition to the case where the temperature measuring device includes a measuring unit and a correcting unit in the housing, as shown in FIG. 16, one or more measuring terminals 1 each including a measuring unit may be connected to a server 2 including a correcting unit via the Internet. In the server 2, the flowchart shown in FIG. 1 is executed, and the temperature measurement result can be displayed on the display surface of the measuring terminal 1 in characters, voice, color, image, etc.

[0083] In addition to the temperature measuring device and the temperature measuring method, the present invention can also be configured as a program for causing a computer to function as each means of the temperature measuring device described above.

[0084] (Modification example)

Description of reference numerals

[0085] 1 ··· Measuring terminal, 2 ··· Server

Claims

1. A temperature measuring device that measures the temperature of a test object based on the ratio of light intensities when receiving radiation energies for two wavelengths that are close to each other with respect to the spectral radiation energy of the test object, comprising: a correction unit that uses a measured value affected by the abundance of an absorber present on the test object or in the optical path from the test object as the original measured value not affected by the abundance of the absorber; The correction unit: uses light included in a first wavelength range having a center wavelength between 900 nm and 1000 nm, which is light of a wavelength at which the change in light intensity when received according to the abundance of the absorber is large and which is absorbed by the absorber, as the first light; uses, as the second light, light included in at least one of a second wavelength range having a center wavelength between 650 nm and 900 nm, a third wavelength range having a center wavelength between 1000 nm and 1080 nm, and a fourth wavelength range having a center wavelength between 1220 nm and 1290 nm, which is light of a wavelength at which the absorption by the absorber is small and the change in light intensity when received according to the abundance of the absorber is small, with respect to the first light; uses, with respect to the spectral radiation energy of a reference light source with a known temperature, light intensity information received for each of a plurality of known abundances as the abundance of the absorber so as to include the two close wavelengths, the wavelength of the first light, and the wavelength of the second light, as the first light intensity information; uses, with respect to the spectral radiation energy of the test object, the light intensity information received when the absorber exists in the existing abundance for the wavelength of the first light as the second light intensity information; uses, with respect to the spectral radiation energy of the test object, the light intensity information received when the absorber exists in the existing abundance for the wavelength of the second light as the third light intensity information; Based on the first light intensity information, the second light intensity information, and the third light intensity information, a temperature measuring device characterized by specifying the received light intensities when the absorber does not exist at one and the other of the two close wavelengths, respectively, and specifying the temperature of the test object based on the ratio of the specified light intensities.

2. specifying a provisional temperature based on the third light intensity information; specifying the abundance of the absorber based on the divisional relationship between the first light intensity information, the second light intensity information, and the third light intensity information; In the case where the absorber does not exist at one and the other of the two adjacent wavelengths, the received light intensities are respectively specified, and the temperature of the object to be inspected is specified based on the ratio of the specified light intensities. The temperature measuring device according to claim 1, characterized in that.

3. Compare by pattern matching based on the additive relationship between the first light intensity information, the second light intensity information, and the third light intensity information, specify the abundance of the absorber, and at one and the other of the two adjacent wavelengths, the received light intensities when the absorber does not exist are respectively specified, and the temperature of the object to be inspected is specified based on the ratio of the specified light intensities. The temperature measuring device according to claim 1, characterized in that.

4. When the absorber is either water or water vapor, or when the absorber contains both water and water vapor, The temperature measuring device according to claim 1, characterized in that it has one wavelength as the first light included in the first wavelength range, two wavelengths as the second light included in the second wavelength range, and one wavelength as the second light included in the third wavelength range.

5. When 90% or more of the absorber is water vapor, The temperature measuring device according to claim 1, characterized in that it has one wavelength as the first light included in the first wavelength range, one wavelength as the second light included in the second wavelength range, one wavelength as the second light included in the third wavelength range, and one wavelength as the second light included in the fourth wavelength range.

6. The temperature measuring device according to claim 1, characterized in that at least one of the two adjacent wavelengths is the same as at least one of the wavelengths of the first light and the second light.

7. The temperature measuring device according to claim 1, characterized in that the absorber is water, water vapor or steam, or a mixture mainly composed of water vapor.

8. The temperature measuring device according to claim 1, characterized in that the spectral radiant energies of the object to be inspected and the reference light source are received by a sensor through a spectroscopic optical system including a prism.

9. A temperature measuring method for measuring the temperature of an object to be inspected based on the ratio of the light intensities when receiving the radiant energies for two wavelengths adjacent to each other with respect to the spectral radiant energy of the object to be inspected. A correction step of using a measured value affected by the abundance of an absorber present on or in the optical path from the object under test as the original measured value not affected by the abundance of the absorber, wherein the correction step uses, as the first light, light included in a first wavelength range having a central wavelength between 900 nm and 1000 nm, which is light having a large change in light intensity when absorbed by the absorber and received according to its abundance, uses, as the second light, light included in at least one of a second wavelength range having a central wavelength between 650 nm and 900 nm, a third wavelength range having a central wavelength between 1000 nm and 1080 nm, and a fourth wavelength range having a central wavelength between 1220 nm and 1290 nm, which is light having a small change in light intensity when absorbed by the absorber and received according to its abundance and having little absorption by the absorber with respect to the first light, uses, as the first light intensity information, light intensity information received for each of a plurality of known abundances as the abundance of the absorber so as to include the two adjacent wavelengths, the wavelength of the first light, and the wavelength of the second light with respect to the spectral radiant energy of a reference light source with a known temperature, uses, as the second light intensity information, light intensity information received when the absorber exists in the abundance in which it actually exists with respect to the wavelength of the first light with respect to the spectral radiant energy of the object under test, uses, as the third light intensity information, light intensity information received when the absorber exists in the abundance in which it actually exists with respect to the wavelength of the second light with respect to the spectral radiant energy of the object under test, based on the first light intensity information, the second light intensity information, and the third light intensity information, a temperature measurement method characterized by specifying the received light intensities when the absorber does not actually exist at one and the other of the two adjacent wavelengths, respectively, and specifying the temperature of the object under test based on the ratio of the specified light intensities.

10. A program for causing a computer to function as each means of the temperature measurement device according to any one of Claims 1 to 8.

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