Wavelength selection method, processing apparatus, method for manufacturing a two-color radiation temperature measurement system, and two-color radiation temperature measurement system

Abstract

This technology provides a way to suppress the decrease in accuracy of temperature measurements. [Solution] A wavelength selection method for a system that measures temperature based on a first optical component and a second optical component spectrally separated from synchrotron radiation of an object to be measured 100, comprising the steps of: obtaining a first spectral emissivity showing the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity showing the relationship between wavelength and emissivity at a second temperature different from the first temperature, for a reference object of the object to be measured 100; obtaining a wavelength band in which the difference between the emissivity of the reference object at the first temperature and the emissivity of the reference object at the second temperature is less than or equal to a predetermined threshold, based on the first and second spectral emissivity; and selecting the first wavelength and the second wavelength from the wavelength band.

Description

Technical Field

[0001] The present invention relates to a wavelength selection method, a processing apparatus, a method for manufacturing a two-color radiation thermometer system, and a two-color radiation thermometer system.

Background Art

[0002] Patent Document 1 discloses a two-color thermometer that splits radiation light from a measurement object into two lights having different wavelengths and measures the temperature of an object using these two lights.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above two-color thermometer can measure temperature non-contact. Therefore, for example, it may be used for measuring the temperature of a part during high-frequency quenching of a rolling bearing part.

[0005] By the way, the above two-color thermometer measures temperature using the ratio of the luminances (radiation amounts) of two lights. The wavelengths of the two lights in the two-color thermometer may be selected as general-purpose wavelengths that enable temperature measurement with a certain accuracy even when the surface state of the object to be measured or the measurement environment changes.

[0006] However, the surface of steel heated to a high temperature by high-frequency quenching may form an oxide film or the formed oxide film may change. Therefore, the emissivity of the part surface during high-frequency quenching may change. Such a change in emissivity becomes an error in the ratio of the luminances of the two lights and a factor that reduces the accuracy of the measured temperature. Therefore, even when the surface of the object to be measured changes, a measure for suppressing a decrease in the accuracy of the measured temperature is desired. [Means for solving the problem]

[0007] The wavelength selection method of this embodiment is a wavelength selection method for selecting the first wavelength of the first optical component and the second wavelength of the second optical component in a two-color radiation temperature measurement system that measures temperature based on a first optical component and a second optical component spectrally separated from the synchrotron radiation of an object to be measured. This wavelength selection method includes the steps of: obtaining a first spectral emissivity showing the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity showing the relationship between wavelength and emissivity at a second temperature different from the first temperature, for a reference object of the object to be measured; obtaining a wavelength band in which the difference between the emissivity of the reference object at the first temperature and the emissivity of the reference object at the second temperature is less than or equal to a predetermined threshold, based on the first and second spectral emissivity; and selecting the first wavelength and the second wavelength from the wavelength band. [Effects of the Invention]

[0008] According to this disclosure, it is possible to suppress the decrease in the accuracy of the measured temperature. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an example of a two-color radiation temperature measurement system according to an embodiment. [Figure 2] Figure 2 shows an example of a holder. [Figure 3] Figure 3 is a flowchart showing an example of a method for generating a calibration table. [Figure 4] Figure 4 is a graph showing an example of the results of measuring the spectral emissivity of a reference object. [Figure 5] Figure 5 is a flowchart showing an example of the wavelength selection process. [Figure 6] Figure 6 shows the partially removed spectral emissivity. [Figure 7]Figure 7 shows a list of multiple first discrete points and multiple second discrete points after discrete points with differences greater than the threshold have been removed. [Figure 8] Figure 8 is a graph showing an example of the amount of infrared radiation emitted by a blackbody at 900°C, and the amount of infrared radiation emitted by a reference object at 900°C. [Figure 9] Figure 9 is a graph showing only the infrared radiation amounts corresponding to the two selected wavelength pairs. [Figure 10] Figure 10 shows an example of the configuration used when generating a calibration table. [Modes for carrying out the invention]

[0010] First, the details of the embodiment will be listed and explained. [Summary of the Embodiment] (1) The embodiment of the wavelength selection method is a wavelength selection method for selecting the first wavelength of the first optical component and the second wavelength of the second optical component in a two-color radiation temperature measurement system that measures temperature based on a first optical component and a second optical component spectrally separated from the synchrotron radiation of an object to be measured. This wavelength selection method includes the steps of: obtaining a first spectral emissivity showing the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity showing the relationship between wavelength and emissivity at a second temperature different from the first temperature, for a reference object of the object to be measured; obtaining a wavelength band in which the difference between the emissivity of the reference object at the first temperature and the emissivity of the reference object at the second temperature is less than or equal to a predetermined threshold, based on the first and second spectral emissivity; and selecting the first wavelength and the second wavelength from the wavelength band. According to the above configuration, by selecting the first and second wavelengths from the wavelength band, the difference between the emissivity of the reference material at the first temperature and the emissivity of the reference material at the second temperature will be below a predetermined threshold. Therefore, the change in the emissivity of the reference material at the first wavelength and the change in the emissivity of the reference material at the second wavelength between the first and second temperatures can be reduced. Therefore, a two-color radiation temperature measurement system is configured based on the selected first and second wavelengths. When this system determines the radiation amounts of the first and second light components of an object for temperature measurement, the change in emissivity between the first and second temperatures is suppressed, and the error due to emissivity included in the radiation amounts of the first and second light components can be reduced. As a result, the decrease in the accuracy of the measured temperature is suppressed.

[0011] (2) In the wavelength selection method described in (1) above, the selection step may include: determining the amount of infrared radiation emitted by the reference object at the first temperature for each of a plurality of candidate wavelengths included in the wavelength band, based on the first spectral emissivity; obtaining a plurality of wavelength pairs from the plurality of candidate wavelengths, each consisting of a pair of candidate wavelengths; determining the ratio of a pair of infrared radiation amounts corresponding to the pair of candidate wavelengths included in each of the plurality of wavelength pairs; and determining at least one selected wavelength pair from the plurality of wavelength pairs, which is selected as the first wavelength and the second wavelength, based on the ratio. In this case, the first and second wavelengths are selected from among multiple wavelength pairs.

[0012] (3) In addition, in the wavelength selection method of (2) above, the step of determining the selected wavelength pair may include the step of determining the selected wavelength pair as a pair of wavelength candidates whose ratio is 0.3 or more and 0.7 or less. If the ratio is less than 0.3, the resolution of the temperature measurement may decrease. Furthermore, if the ratio is greater than 0.7, the error in the ratio of the first and second infrared radiation components from the object being measured may increase. By selecting a wavelength pair that includes a pair of wavelength candidates with a ratio of 0.3 or higher and 0.7 or lower, appropriate first and second wavelengths can be selected.

[0013] (4) Further, in the wavelength selection method of (2) or (3) above, when there are a plurality of the at least one selected wavelength pairs, the method may further include a step of selecting, as the first wavelength and the second wavelength, a selected wavelength pair including a candidate wavelength having the smallest value among the plurality of selected wavelength pairs. When the wavelength is short, the amount of infrared radiation is large, and the change in emissivity due to the presence or absence of an oxide film formed on the surface of the object to be measured is small. Therefore, the error included in the radiation amount of each of the first light component and the second light component can be made smaller, and the decrease in the accuracy of the measured temperature can be further suppressed.

[0014] (5) From another aspect, an embodiment is a processing device that performs a process of selecting a first wavelength of the first light component and a second wavelength of the second light component in a two-color radiation temperature measurement system that measures temperature based on the first light component and the second light component spectrally separated from the radiation light of the object to be measured. This processing device includes a processing unit having a function of performing a process of obtaining a first spectral emissivity indicating the relationship between the wavelength and the emissivity at a first temperature, and a second spectral emissivity indicating the relationship between the wavelength and the emissivity at a second temperature different from the first temperature, for a reference object of the object to be measured; a process of obtaining a wavelength band in which the difference between the emissivity of the reference object at the first temperature and the emissivity of the reference object at the second temperature is equal to or less than a predetermined threshold value, based on the first spectral emissivity and the second spectral emissivity; and a process of selecting the first wavelength and the second wavelength from within the wavelength band.

[0015] (6) Further, an embodiment from another perspective is a method for manufacturing a two-color radiation temperature measurement system that performs temperature measurement based on a first light component and a second light component spectroscopically separated from the radiation light of the object to be measured. This method includes steps of obtaining, for a reference object of the object to be measured, a first spectral emissivity indicating the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity indicating the relationship between wavelength and emissivity at a second temperature different from the first temperature; obtaining a wavelength band in which the difference between the emissivity at the first temperature and the emissivity at the second temperature is below a predetermined threshold value based on the first spectral emissivity and the second spectral emissivity; and a selection step of selecting a first wavelength of the first light component and a second wavelength of the second light component from within the wavelength band.

[0016] (7) Further, an embodiment from another perspective is a two-color radiation temperature measurement system manufactured by the manufacturing method described in (6) above.

[0017] (8) In the two-color radiation temperature measurement system of (7) above, the ratio between the infrared radiation amount of the reference object obtained from the emissivity corresponding to the first wavelength and the infrared radiation amount of the reference object obtained from the emissivity corresponding to the second wavelength may be 0.3 or more and 0.7 or less. In this case, a decrease in the accuracy of the measured temperature is more effectively suppressed.

[0018] [Details of Embodiment] Hereinafter, preferred embodiments will be described with reference to the drawings.

[0019] [Regarding the Two-Color Radiation Temperature Measurement System] FIG. 1 is a diagram showing an example of a two-color radiation temperature measurement system according to an embodiment. The two-color radiation temperature measurement system 1 is a system that detects radiation light from the object to be measured 100 and calculates the measured temperature of the object to be measured 100 based on the detection result. The two-color radiation temperature measurement system 1 (hereinafter, also simply referred to as the measurement system 1) can obtain the measured temperature of the object to be measured 100 without contacting the object to be measured 100. The measurement system 1 of this embodiment is used, for example, for temperature control of parts that are subjected to high-frequency induction hardening. Parts subjected to high-frequency induction hardening include the raceways of rolling bearings, etc. In other words, the object to be measured 100 includes the raceways of rolling bearings, etc. Measurement system 1 measures the temperature of the component during high-frequency heating.

[0020] The measurement system 1 comprises a main unit 2 and a processing unit 4. The main unit 2 includes a light receiving unit 6, a spectral unit 10, a first bandpass filter 12, a first sensor 14, a second bandpass filter 16, and a second sensor 18. The light-receiving unit 6 includes an objective lens that receives the light emitted from the object to be measured 100, and an optical fiber that guides the received light to the spectroscopic unit 10. As described above, the object to be measured 100 includes the raceway rings of a rolling bearing that are subjected to high-frequency induction hardening. The raceway rings (object to be measured 100) are set in a high-frequency induction hardening apparatus and heated by high-frequency induction. The light-receiving unit 6 may have a mounting portion that is attached to a high-frequency induction hardening apparatus in which the object to be measured 100 is set. The light-receiving unit 6 is mounted by the mounting portion in a position where it can receive the radiant light from the object to be measured 100 that is being heated by high frequency. The light receiving unit 6 guides the radiant light from the object to be measured 100 to the spectroscopic unit 10.

[0021] The spectroscopic unit 10 has the function of splitting synchrotron radiation into a first spectroscopic component and a second spectroscopic component. The wavelength bands of the first spectroscopic component and the wavelength bands of the second spectroscopic component are different from each other. The first spectral component is directed to the first bandpass filter 12. The second spectral component is directed to the second bandpass filter 16.

[0022] The first bandpass filter 12 has a passband that includes the first wavelength λ1. The first bandpass filter 12 allows the first optical component of the first spectral component that includes the first wavelength λ1 to pass through. The second bandpass filter 16 has a passband that includes the second wavelength λ2. The second bandpass filter 16 allows the second optical component of the second spectral component to pass through in the band that includes the second wavelength λ2.

[0023] The first wavelength λ1 and the second wavelength λ2 are wavelengths selected by a wavelength selection process described later. In this embodiment, the first wavelength λ1 is assumed to be shorter than the second wavelength λ2.

[0024] The first light component is directed to the first sensor 14. The first sensor 14 has the function of detecting the amount of infrared radiation from the first light component. The first sensor 14 is connected to the processing unit 4. The output indicating the detection result from the first sensor 14 is provided to the processing unit 4. The second light component is directed to the second sensor 18. The second sensor 18 has the function of detecting the amount of infrared radiation from the second light component. The second sensor 18 is connected to the processing unit 4. The output indicating the detection result from the second sensor 18 is provided to the processing unit 4.

[0025] The first bandpass filter 12 (second bandpass filter 16) is held by a holder positioned between the spectroscopic unit 10 and the first sensor 14 (second sensor 18). Figure 2 shows an example of a holder. Figure 2 shows a holder 20 that holds the first bandpass filter 12. The holder that holds the second bandpass filter 16 has a similar configuration to holder 20. Therefore, this section will describe holder 20, and the description of the holder that holds the second bandpass filter 16 will be omitted.

[0026] In Figure 2, the first bandpass filter 12 is held in a holder 20. The holder 20 extends from a case 15. The case 15 houses and holds the first sensor 14. The holder 20 is a cylindrical member that connects the spectrometer 10 and the case 15. The holder 20 has an optical guide path 20a inside. The first bandpass filter 12 is held within the optical guide path 20a. The optical guide path 20a guides the first spectral component from the spectrometer 10 to the first bandpass filter 12 and also guides the first optical component to the first sensor 14 inside the case 15.

[0027] The holder 20 has a notch 20b. The notch 20b is an opening for positioning the first bandpass filter 12 within the light guide path 20a of the holder 20. The first bandpass filter 12 is detachably positioned in the light guide path through the notch 20b from outside the holder 20. Therefore, by preparing multiple bandpass filters with different passbands, it becomes possible to select and replace the first bandpass filter 12 from among the multiple bandpass filters, thereby changing the first wavelength λ1 of the first optical component and the second wavelength λ2 of the second optical component. This makes it possible to change the first wavelength λ1 of the first optical component and the second wavelength λ2 of the second optical component according to the object under measurement 100 and the measurement temperature.

[0028] The processing unit 4 includes a computer, a server, etc. The processing unit 4 has a processing unit 4a, a storage unit 4b, and an input / output unit 4c. The processing unit 4a includes, for example, a CPU (Central Processing Unit).

[0029] The memory unit 4b includes, for example, flash memory, hard disk, SSD (Solid State Drive), ROM (Read Only Memory), RAM (Random Access Memory), etc. The memory unit 4b stores computer programs and necessary information for the processing unit 4a to execute. The processing unit 4a realizes its various processing functions by executing computer programs stored on a non-transient recording medium that can be read by a computer, such as the memory unit 4b. Furthermore, the memory unit 4b stores the calibration table 5. The calibration table 5 is used in the process of calculating the temperature of the object to be measured 100. The calibration table 5 will be explained later.

[0030] The input / output section 4c includes an I / O interface and input / output devices. The first sensor 14 and the second sensor 18 are connected to the I / O interface in a communication manner. Input / output devices have the function of receiving operations from the operator of measurement system 1 and outputting various information to the outside. Input / output devices include keyboards, mice, touch panels, monitors, printers, speakers, etc.

[0031] The processing unit 4a has the function of performing a measurement temperature calculation process. The measurement temperature calculation process is a process that calculates the measurement temperature of the object to be measured 100 based on the output of the first sensor 14 and the second sensor 18. In the temperature measurement calculation process, the processing unit 4a first receives an output indicating the detection results from the first sensor 14 and the second sensor 18, which are obtained by temperature measurement performed by the main unit 2.

[0032] Next, the processing unit 4a determines the measurement ratio R. The measurement ratio R is the ratio of the amount of infrared radiation of the first light component obtained from the output of the first sensor 14 to the amount of infrared radiation of the second light component obtained from the second sensor 18.

[0033] The processing unit 4a, which has determined the measurement ratio R, refers to the calibration table 5 and determines the measurement temperature of the object to be measured 100. Calibration table 5, as described later, registers the temperature of the object under test 100 and the reference ratio in association with each other. The processing unit 4a refers to calibration table 5 and determines the temperature corresponding to the reference ratio that corresponds to the obtained measurement ratio R as the measured temperature of the object under test 100. The obtained measured temperature is output via the input / output unit 4c.

[0034] Calibration table 5 is generated in advance before measuring the temperature of the object 100 to be measured. In other words, the two-color radiation temperature measurement system 1 is completed by preparing the above-mentioned devices and creating calibration table 5.

[0035] [Regarding the method for generating proofreading tables] Figure 3 is a flowchart showing an example of a method for generating calibration table 5. In this generation method, first, the spectral emissivity of a reference material corresponding to the object to be measured 100 is measured (step S1). The spectral emissivity of a reference material is a set of data showing the relationship between the wavelength of synchrotron radiation and the emissivity of the reference material at a specific temperature. This data set includes graphs, tables, and mathematical formulas illustrating the relationship between wavelength and emissivity. Furthermore, emissivity is the ratio of the radiation output (radiant exitivity) of a radiation source to the radiation output (radiant exitivity) of a black body at the same temperature as the radiation source. Radiation output (radiant exitivity) is the radiant flux (radiant energy) emitted by a radiation source per unit area.

[0036] The reference object is made of the same material as the object being measured 100. Furthermore, the reference object has a surface that is as similar as possible to the surface of the object being measured 100. The following explanation describes a case where the object to be measured 100 is a component of a rolling bearing, the material of the object to be measured 100 is SUJ2, which is bearing steel specified by JIS standards, and the measurement system 1 is used to measure the temperature of the object to be measured 100 during quenching.

[0037] The spectral emissivity of the object 100 is measured at two temperatures. These two temperatures represent the upper and lower limits of the measurement temperature range of the measurement system 1. The quenching temperature of SUJ2 measured by the measurement system 1 is approximately 800°C to 850°C. Therefore, in this embodiment, the reference material is made of SUJ2, and the measurement temperature range of the measurement system 1 is set to 800°C to 900°C. Thus, the first temperature, one of the two temperatures, is set to 900°C, and the second temperature, the other, is set to 800°C.

[0038] Spectral emissivity is measured by a spectral emissivity analyzer. A spectral emissivity analyzer has the function of measuring spectral emissivity while maintaining a reference material at a constant measurement temperature. Figure 4 is a graph showing an example of the results of measuring the spectral emissivity of a reference material. In Figure 4, the horizontal axis represents wavelength, and the vertical axis represents emissivity. In Figure 4, the spectral emissivity at 900°C (first spectral emissivity) is shown by a solid line, and the spectral emissivity at 800°C (second spectral emissivity) is shown by a dashed line. Furthermore, Figure 4 shows the spectral emissivity from wavelengths of 2.5 nm to 5.5 nm.

[0039] As shown in Figure 3, after the measurement of the spectral emissivity of the reference material is completed (step S1), a wavelength selection process is performed (step S2). The wavelength selection process is the process of selecting the first wavelength λ1 and the second wavelength λ2. The wavelength selection process is performed by the processing unit 4a of the processing unit 4. Once the selection of the first wavelength λ1 and the second wavelength λ2 through the wavelength selection process is complete, the calibration table 5 is generated. The following explains the wavelength selection process.

[0040] [Regarding wavelength selection processing] Figure 5 is a flowchart showing an example of the wavelength selection process. In the wavelength selection process, the processing unit 4a first receives the spectral emissivity measurement data (step S11). Measurement data is received via the input / output unit 4c of the processing unit 4. The operator of the measurement system 1 provides measurement data to the processing unit 4 by operating the input / output unit 4c. The processing unit 4a receives operation input from the operator via the input / output unit 4c.

[0041] Next, the processing unit 4a deletes data from the measurement data for wavelength bands that are not used (step S12). The measurement environment in this embodiment is the atmosphere. In the atmosphere, there are wavelength bands in which infrared radiation is greatly absorbed by moisture and carbon dioxide. It is difficult to accurately measure the amount of infrared radiation in wavelength bands in which infrared radiation absorption by the atmosphere is great. Therefore, the processing unit 4a deletes data from the measurement data that is in the wavelength band where infrared absorption is high.

[0042] Figure 6 shows the spectral emissivity with some parts removed. In Figure 6, bands W1 and W2 are wavelength bands where infrared absorption by the atmosphere is large. Band W1 is a band where infrared absorption by water vapor (H2O) is particularly prominent. Band W2 is a band where infrared absorption by carbon dioxide (CO2) is particularly prominent. Band W1 is in the range of approximately 2.5 nm to 3.4 nm, and band W2 is in the range of approximately 4.2 nm to 4.4 nm. The processing unit 4a treats bandwidths W1 and W2 as wavelength bands that are not used.

[0043] The processing unit 4a deletes the data for bands W1 and W2, which are wavelength bands that are not used, from the measurement data. As a result, the processing unit 4a performs subsequent processing without using the data for bands W1 and W2.

[0044] Next, as shown in Figure 5, the processing unit 4a discretizes the spectral emissivity in predetermined wavelength units Δλ (step S13). In Figure 6, the spectral emissivity at 900°C includes multiple first discrete points P1. In Figure 6, the multiple first discrete points P1 are shown as black dots. The spectral emissivity at 800°C includes multiple second discrete points P2. In Figure 6, these multiple second discrete points P2 are shown as open dots. Multiple first discrete points P1 and multiple second discrete points P2 represent the emissivity for 15 wavelengths determined by the wavelength unit Δλ. These 15 wavelengths are candidate wavelengths for the first wavelength λ1 and the second wavelength λ2 (candidate wavelengths λc1 to λc15).

[0045] Next, the processing unit 4a calculates the difference in emissivity between discrete points of the same wavelength (step S14). As shown in Figure 6, the processing unit 4a calculates the difference d between the first discrete point P1 and the second discrete point P2, which are the same candidate wavelength. The processing unit 4a calculates the difference d for each of the 15 candidate wavelengths λc1 to λc15.

[0046] As shown in Figure 5, the processing unit 4a, which has calculated multiple differences d, identifies a target wavelength band in which the differences d are below a predetermined threshold (step S15). The processing unit 4a compares each of the multiple differences d with a threshold Thd. Based on the comparison, the processing unit 4a defines the bandwidth containing discrete points P1 and P2, where the difference d is less than or equal to the threshold Thd, as the target wavelength bandwidth. Processing unit 4a removes discrete points P1 and P2 whose difference d is greater than the threshold Thd.

[0047] For example, in Figure 6, let's assume that the difference d between candidate wavelengths λc7 to λc10 and candidate wavelength λc15 is greater than the threshold Thd. In this case, the first discrete point P1 and the second discrete point P2 corresponding to candidate wavelengths λc7 to λc10 and candidate wavelength λc15 are removed.

[0048] Figure 7 shows the multiple first discrete points P1 and multiple second discrete points P2 after discrete points P1 and P2 with a difference d greater than the threshold Thd have been removed. As shown in Figure 7, after the removal of discrete points P1 and P2 with a difference d greater than the threshold Thd, the multiple first discrete points P1 and multiple second discrete points P2 include the first discrete points P1 and second discrete points P2 for each of the candidate wavelengths λc1 to λc6 and candidate wavelengths λc11 to λc14.

[0049] The processing unit 4a identifies the wavelength band containing candidate wavelengths λc1 to λc6 as the target wavelength band TW1, and the wavelength band containing candidate wavelengths λc11 to λc14 as the target wavelength band TW2. Furthermore, since a relatively large difference d can lead to errors in temperature measurement, the threshold Thd is set to a value that allows the difference d to be judged as sufficiently close.

[0050] Next, as shown in Figure 5, the processing unit 4a calculates the amount of infrared radiation emitted by the reference object at 900°C for each of the multiple candidate wavelengths included in the target wavelength bands TW1 and TW2 (step S16). The processing unit 4a first calculates the amount of blackbody infrared radiation at 900°C for each of several candidate wavelengths. The amount of blackbody infrared radiation can be calculated based on Planck's law. The processing unit 4a calculates the amount of infrared radiation emitted by a reference object at 900°C based on the amount of blackbody infrared radiation at 900°C and the spectral emissivity at 900°C.

[0051] Figure 8 is a graph showing an example of the amount of infrared radiation emitted by a blackbody at 900°C, and the amount of infrared radiation emitted by a reference object at 900°C. In Figure 8, the black dots represent the amount of blackbody infrared radiation at 900°C. The white triangular dots A1-A6 and A11-A14 represent the amount of infrared radiation of a reference object at 900°C.

[0052] The amount of blackbody infrared radiation at 900°C can be determined for each of the candidate wavelengths λc1 to λc6 and λc11 to λc14. The processing unit 4a calculates the infrared radiation of the reference object by multiplying the blackbody infrared radiation by the emissivity. The processing unit 4a multiplies the amount of blackbody infrared radiation at 900°C at the candidate wavelength λc1 by the emissivity at 900°C at the candidate wavelength λc1 (Figure 7) to obtain the amount of infrared radiation of the reference object at 900°C at the candidate wavelength λc1. Similarly, the processing unit 4a obtains the amount of infrared radiation from the reference object at 900°C at candidate wavelengths λc2 to λc6 and candidate wavelengths λc11 to λc14.

[0053] In Figure 8, points A1-A6 and A11-A14 plot the infrared radiation of the reference material at 900°C for candidate wavelengths λc1-λc6 and λc11-λc14, respectively. In this way, the processing unit 4a calculates the amount of infrared radiation emitted by a reference object at 900°C for each of several candidate wavelengths included in the target wavelength bands TW1 and TW2.

[0054] Next, as shown in Figure 5, the processing unit 4a identifies a wavelength pair from among a plurality of candidate wavelengths by combining a pair of candidate wavelengths (step S17). The processing unit 4a in this embodiment identifies all combinations of candidate wavelengths λc1 to λc6 and candidate wavelengths λc11 to λc14. Therefore, the total number of wavelength pairs is 45.

[0055] Next, the processing unit 4a calculates the ratio r (step S18). The ratio r is the ratio of the amount of infrared radiation corresponding to a pair of candidate wavelengths included in a wavelength pair. For example, the ratio r in a wavelength pair combining candidate wavelength λc1 and candidate wavelength λc6 is the ratio of the infrared radiation amount a1 shown at point A1 to the infrared radiation amount a6 shown at point A6 in Figure 8. The choice of whether to calculate the ratio r as a1 / a6 or a6 / a1 depends on whether the ratio is less than or equal to 1. The processing unit 4a calculates the ratio r for each of the 45 wavelength pairs.

[0056] Next, as shown in Figure 5, the processing unit 4a identifies wavelength pairs where the ratio r is 0.3 or greater and 0.7 or less (step S19). The processing unit 4a identifies wavelength pairs from among the 45 wavelength pairs in which the ratio r is 0.3 or greater and 0.7 or less as selected wavelength pairs to be selected as the first wavelength and the second wavelength.

[0057] Once the selected wavelength pair is identified, the processing unit 4a proceeds to step S20. In step S20, if it is determined that there is one selected wavelength pair, the processing unit 4a selects a pair of candidate wavelengths included in this one selected wavelength pair as the first wavelength λ1 and the second wavelength λ2 (step S21), and then finishes processing.

[0058] If, in step S20, it is determined that there is more than one selected wavelength pair (i.e., there are multiple selected wavelength pairs), the processing unit 4a proceeds to step S22. In step S22, the processing unit 4a selects a pair of selected wavelengths that includes the smallest candidate wavelength from among a plurality of selected wavelength pairs as the first wavelength λ1 and the second wavelength λ2, and then completes the processing.

[0059] In this embodiment, for example, the combination of candidate wavelength λc1 and candidate wavelength λc5, and the combination of candidate wavelength λc12 and candidate wavelength λc13 are identified as selected wavelength pairs. Figure 9 is a graph showing only the infrared radiation amounts corresponding to these two selected wavelength pairs. In Figure 9, candidate wavelength λc1 is the smallest candidate wavelength. Therefore, the processing unit 4a selects a selection wavelength pair including candidate wavelength λc1 and candidate wavelength λc5 as the first wavelength λ1 and the second wavelength λ2. In other words, the processing unit 4a selects candidate wavelength λc1 as the first wavelength λ1 and candidate wavelength λc5 as the second wavelength λ2.

[0060] [Regarding the generation of the proofreading table] Once the selection of the first wavelength λ1 and the second wavelength λ2 through the wavelength selection process is complete, the calibration table 5 is generated as shown in Figure 3 (step S3). Calibration table 5 is generated using measurement system 1 and blackbody furnace 30, as shown in Figure 10. Calibration table 5 contains records that associate temperature with reference ratio.

[0061] First, the operator of the measurement system 1 selects a bandpass filter from among several bandpass filters that has a passband including the first wavelength λ1 and uses it as the first bandpass filter 12. The operator also selects a bandpass filter from among several bandpass filters that has a passband including the second wavelength λ2 and uses it as the second bandpass filter 16.

[0062] Next, the processing unit 4a controls the temperature of the blackbody furnace 30 and determines the measurement ratio between the amount of infrared radiation of the first light component and the amount of infrared radiation of the second light component, which are spectrally separated from the synchrotron radiation from the blackbody furnace 30. The processing unit 4a registers the set temperature and measurement ratio of the blackbody furnace 30 as the temperature and reference ratio in the calibration table 5. In this way, the processing unit 4a generates the calibration table 5.

[0063] When determining the temperature of the object 100 to be measured, the processing unit 4a calculates the measurement ratio of the infrared radiation of the first optical component and the infrared radiation of the second optical component, which are spectrally separated from the synchrotron radiation of the object 100 to be measured. This measurement ratio is compared with the reference ratio in the calibration table 5. The processing unit 4a outputs the temperature corresponding to the reference ratio that corresponds to the measurement ratio as the measured temperature.

[0064] As described above, the wavelength selection process (wavelength selection method) of this embodiment includes the steps of obtaining the spectral emissivity at 900°C (first spectral emissivity) and the spectral emissivity at 800°C (second spectral emissivity) for a reference object (step S11), obtaining a target wavelength band in which the difference d is less than or equal to a predetermined threshold (step S15), and selecting a first wavelength λ1 and a second wavelength λ2 from the target wavelength band (steps S16 to S22).

[0065] With this configuration, by selecting the first wavelength λ1 and the second wavelength λ2 from the target wavelength bands TW1 and TW2, the difference d between the emissivity of the reference material at 900°C (first temperature) and the emissivity of the reference material at 800°C (second temperature) becomes less than or equal to a predetermined threshold, and the emissivity of the reference material at 900°C and the emissivity of the reference material at 800°C become relatively close. As a result, the change in the emissivity of the reference material at the first wavelength λ1 and the change in the emissivity of the reference material at the second wavelength λ2 between 900°C and 800°C can be reduced. Therefore, a calibration table 5 is generated based on the selected first wavelength λ1 and second wavelength λ2. When this system 1 determines the radiation amounts of the first and second optical components of the object 100 for temperature measurement, even if the surface of the object 100 changes, the change in emissivity is suppressed between 900°C and 800°C, and the error included in the infrared radiation amounts of the first and second optical components can be reduced. As a result, the decrease in the accuracy of the measurement temperature is suppressed.

[0066] Furthermore, the above selection step includes the steps of: determining the amount of infrared radiation of a reference object at 900°C for each of several candidate wavelengths included in the target wavelength bands TW1 and TW2 (step S16); obtaining multiple wavelength pairs from the multiple candidate wavelengths by combining a pair of candidate wavelengths (step S17); determining the ratio r corresponding to each of the multiple wavelength pairs (step S18); and determining at least one selected wavelength pair from the multiple wavelength pairs that is selected for the first wavelength λ1 and the second wavelength λ2 based on the ratio r. This allows the first wavelength λ1 and the second wavelength λ2 to be selected from among multiple wavelength pairs.

[0067] Furthermore, in this embodiment, the step of determining the selected wavelength pair includes the step of determining a wavelength pair as the selected wavelength pair (step S19), which includes a pair of wavelength candidates whose ratio r is 0.3 or more and 0.7 or less. This ratio r is a reference value used to compare the measured ratio of infrared radiation used during temperature measurement. Therefore, if the ratio r is less than 0.3, the resolution of the temperature measurement may decrease. Also, if the ratio r is greater than 0.7, the error in the ratio of the first and second infrared radiation components from the object being measured may increase. By selecting a wavelength pair that includes a pair of wavelength candidates with a ratio r of 0.3 or greater and 0.7 or less, appropriate first wavelength λ1 and second wavelength λ2 can be selected. Furthermore, a more preferable range for the ratio r is 0.4 or greater and 0.6 or less. In this case, more appropriate first wavelength λ1 and second wavelength λ2 can be selected.

[0068] Furthermore, this embodiment further includes a step (step S22) of selecting a pair of selected wavelengths that includes the candidate wavelength with the smallest value from among a plurality of selected wavelength pairs as the first wavelength λ1 and the second wavelength λ2. Shorter wavelengths result in higher infrared radiation and less change in emissivity due to the presence or absence of an oxide film on the surface of the object 100 being measured. Therefore, errors in the radiation amounts of the first and second optical components can be reduced, and the decrease in the accuracy of the measured temperature can be further suppressed.

[0069] Furthermore, the measurement system 1 obtained through the wavelength selection process described above has a ratio of 0.3 or more and 0.7 or less between the amount of infrared radiation obtained from the emissivity corresponding to the first wavelength λ1 and the amount of infrared radiation obtained from the emissivity corresponding to the second wavelength λ2. Therefore, this measurement system 1 can further suppress the decrease in the accuracy of the measured temperature.

[0070] 〔others〕 The embodiments disclosed herein are illustrative in all respects and not restrictive. For example, in the above embodiment, the selected wavelength pair is described as a pair of wavelength candidates with a ratio r of 0.3 or more and 0.7 or less. However, the ratio r may be outside this numerical range. Nevertheless, by selecting a wavelength pair with a ratio r of 0.3 or more and 0.7 or less, appropriate first wavelength λ1 and second wavelength λ2 can be selected. The scope of the present invention is not limited to the embodiments described above and includes all modifications within the scope equivalent to the configurations described in the claims. [Explanation of symbols]

[0071] 1. Two-color infrared temperature measurement system 2 Main body 4 Processing Unit 4a Processing Unit 4b Storage section 4c input / output section 5 Calibration Table 6 Light receiving part 10 Spectroscopic section 12. First bandpass filter 14. First Sensor 15 cases 16. Second bandpass filter 18. Second Sensor 20 holders 20a light guide path 20b Notch 30 Blackbody Furnaces 100 Object to be measured

Claims

1. A wavelength selection method for selecting the first wavelength of the first optical component and the second wavelength of the second optical component in a two-color radiation temperature measurement system that measures temperature based on a first optical component and a second optical component spectrally separated from the synchrotron radiation of an object to be measured, The steps include obtaining a first spectral emissivity showing the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity showing the relationship between wavelength and emissivity at a second temperature different from the first temperature, for a reference object of the object being measured. A step of obtaining a wavelength band in which the difference between the emissivity of the reference material at the first temperature and the emissivity of the reference material at the second temperature is less than or equal to a predetermined threshold, based on the first spectral emissivity and the second spectral emissivity, The method includes a selection step of selecting the first wavelength and the second wavelength from the aforementioned wavelength band. Wavelength selection method.

2. The aforementioned selection step is, The steps include determining the amount of infrared radiation emitted by the reference object at a first temperature for each of a plurality of candidate wavelengths included in the wavelength band, based on the first spectral emissivity, The steps include obtaining multiple wavelength pairs by combining a pair of candidate wavelengths from among the aforementioned multiple candidate wavelengths, The steps include determining the ratio of a pair of infrared radiation amounts corresponding to the pair of candidate wavelengths included in each of the plurality of wavelength pairs, The step of determining at least one selected wavelength pair from the plurality of wavelength pairs to be selected as the first wavelength and the second wavelength, based on the ratio, is included. The wavelength selection method according to claim 1.

3. The step of determining the selected wavelength pair includes determining a wavelength pair that includes a pair of wavelength candidates whose ratio is 0.3 or more and 0.7 or less, as the selected wavelength pair. The wavelength selection method according to claim 2.

4. The aforementioned at least one selected wavelength pair can be multiple, The step further includes selecting a pair of selected wavelengths that includes the candidate wavelength with the smallest value among the plurality of selected wavelength pairs as the first wavelength and the second wavelength. The wavelength selection method according to claim 2.

5. A processing apparatus for selecting a first wavelength of the first light component and a second wavelength of the second light component in a two-color radiation temperature measurement system that measures temperature based on a first light component and a second light component spectrally separated from synchrotron radiation of an object to be measured, A process to obtain, with respect to the reference object of the object to be measured, a first spectral emissivity showing the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity showing the relationship between wavelength and emissivity at a second temperature different from the first temperature, A process to obtain a wavelength band in which the difference between the emissivity of the reference object at the first temperature and the emissivity of the reference object at the second temperature is less than or equal to a predetermined threshold, based on the first and second spectral emissivity, The system includes a processing unit that performs a process of selecting the first wavelength and the second wavelength from the aforementioned wavelength band. Processing device.

6. A method for manufacturing a two-color radiation temperature measurement system that measures temperature based on a first and second light component spectrally separated from the synchrotron radiation of an object to be measured, The steps include obtaining a first spectral emissivity showing the relationship between wavelength and emissivity at a first temperature, and a second spectral emissivity showing the relationship between wavelength and emissivity at a second temperature different from the first temperature, for a reference object of the object being measured. A step of obtaining a wavelength band in which the difference between the emissivity at the first temperature and the emissivity at the second temperature is less than or equal to a predetermined threshold, based on the first and second spectral emissivity. The method includes a selection step of selecting a first wavelength of the first optical component and a second wavelength of the second optical component from the aforementioned wavelength band. A method for manufacturing a two-color radiation temperature measurement system.

7. Manufactured by the manufacturing method described in claim 6 Two-color infrared temperature measurement system.

8. The ratio of the amount of infrared radiation of the reference object determined from the emissivity corresponding to the first wavelength to the amount of infrared radiation of the reference object determined from the emissivity corresponding to the second wavelength is 0.3 or more and 0.7 or less. The two-color radiation temperature measurement system according to claim 7.

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