Multispectral radiation temperature field measurement device and method based on MEMS galvanometer

Abstract

A multispectral radiation temperature field measurement device and method based on a MEMS galvanometer can improve the calibration accuracy of traditional temperature measurement devices and methods when calibrating instruments, while overcoming the measurement error caused by the inability to modify the selected wavelength in traditional temperature measurement devices. It includes: a MEMS galvanometer scanning imaging device, a spectral information acquisition device, and a temperature field inversion information calculation device. The MEMS galvanometer scanning imaging device and the spectral information acquisition device are connected via optical fiber coupling, and the spectral information acquisition device and the temperature field inversion information calculation device are electrically connected.

Description

Technical Field

[0001] This invention belongs to the technical field of multi-wavelength temperature field radiation temperature measurement, and particularly relates to a multispectral radiation temperature field measurement device based on a MEMS galvanometer, and a multispectral radiation temperature field measurement method based on a MEMS galvanometer. Background Technology

[0002] Multispectral temperature field radiation measurement is a crucial branch of non-contact temperature measurement methods, primarily applied in high-temperature measurement. It holds significant value and promising prospects in fields such as metal smelting, high-temperature measurement of internal combustion engines, and high-temperature furnace temperature testing. Achieving high-temperature measurement is of paramount importance to various industries and sectors with high-temperature control requirements.

[0003] Multispectral temperature measurement methods are based on Planck's blackbody radiation law, the Stefan-Boltzmann law, and Wien's displacement law. Under the constraints of these physical laws, a correspondence between radiation wavelength, radiation energy, and temperature is established. The multi-wavelength temperature measurement method selects appropriate wavelengths and measures the radiation energy at those wavelengths, thereby solving for the actual temperature based on the physical relationship. The selection of multiple wavelengths is due to the uncertainty of the target emissivity during actual measurement. For an ideal blackbody, its emissivity is 1, but in actual measurement, the target object is mostly a gray body, resulting in an unknown emissivity. The emissivity varies for different wavelengths; therefore, multiple wavelengths need to be introduced, and an emissivity model needs to be constructed to obtain an accurate analytical solution using multispectral radiation thermometry. By first calibrating the actual measurement results using a high-temperature blackbody furnace, effective calibration results can be obtained under the condition of blackbody radiation.

[0004] When calibrating temperature measuring devices using high-temperature blackbody furnaces, due to structural limitations, multi-wavelength temperature measuring devices often employ filter-based spectral dispersion to obtain calibration parameters for the corresponding wavelengths. While theoretically, under the condition of satisfying the blackbody radiation law, selecting different wavelengths should not theoretically cause data differences, in actual measurements, the signal-to-noise ratio (SNR) of the detector limits the selection of multi-wavelength data. Therefore, when choosing multi-wavelength data, the band with the highest possible SNR should be selected for calculation. Furthermore, with filters, the spectral energy distribution changes when the target temperature changes, making it impossible to effectively select the optimal wavelength for measurement. On the other hand, after selecting a specific wavelength, traditional multi-wavelength high-temperature measuring devices using filter-based spectral dispersion for calibration in high-temperature blackbody furnaces are prone to intensity errors due to the resolution bandwidth limitations of the filters, introducing measurement errors during the standard blackbody furnace calibration stage. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a multispectral radiation temperature field measurement device based on MEMS galvanometer, which can improve the calibration accuracy of traditional temperature measurement devices and methods when calibrating instruments, and at the same time overcome the measurement error caused by the inability to modify the selected wavelength in traditional temperature measurement devices.

[0006] The technical solution of the present invention is: a multispectral radiation temperature field measurement device based on a MEMS galvanometer, comprising: a MEMS galvanometer scanning imaging device, a spectral information acquisition device, and a temperature field inversion information calculation device, wherein the MEMS galvanometer scanning imaging device and the spectral information acquisition device are connected by optical fiber coupling, and the spectral information acquisition device and the temperature field inversion information calculation device are electrically connected.

[0007] The scanning imaging device of MEMS galvanometers realizes the function of scanning imaging of temperature field through real-time control of 2D micro galvanometers and corresponding optical path calculation.

[0008] The spectral information acquisition device is used to acquire the spectral radiance information of a distant target under different wavelength conditions. It uses an optical fiber coupling method to build a symmetrical Czerny-Turner structure optical path through a reflective blazed grating. The actual energy coupled into the optical fiber is spectrally dispersed, and then a detector is used to perform photoelectric information conversion on the dispersed spectrum to finally obtain the corresponding spectral curve.

[0009] The temperature field inversion information calculation device is used to amplify, filter, collect, process, and analyze the photoradiance signals of the target under different wavelengths obtained by the spectral information acquisition device, and calculate the corresponding target temperature by combining the spectral information.

[0010] This invention improves the calibration accuracy of traditional temperature measuring devices and methods by constructing a multispectral radiation temperature field measurement device based on MEMS galvanometers and the corresponding high-temperature measurement method. At the same time, it can more effectively overcome the measurement error caused by the inability to modify the wavelength selection in traditional temperature measuring devices by selecting detailed spectral information. It can solve the problem that current multispectral temperature measuring devices cannot dynamically select the corresponding energy parameters for calculation and optimizes the error generated in the calibration stage to improve measurement accuracy.

[0011] A method for measuring the temperature field of such a MEMS galvanometer-based multispectral radiation temperature field is also provided, which includes the following steps:

[0012] (1) Align the MEMS galvanometer-based multispectral radiation temperature field measuring device with the standard high-temperature blackbody radiation furnace, reset the MEMS galvanometer, adjust the temperature of the high-temperature blackbody radiation furnace to a wavelength range suitable for the APD detector to respond well, and obtain the spectral curve information of the corresponding point.

[0013] (2) Use the wavelength characteristic inversion algorithm to obtain the wavelength and corresponding characteristic information after the algorithm optimization, and then calibrate it;

[0014] (3) Select six wavelengths and perform temperature calculations on the calibrated data respectively to obtain the corresponding spectral energy information calculated by the wavelength characteristic inversion algorithm, and calculate the calibration function model at the corresponding temperature.

[0015] (4) Substitute the calibration coefficient function into the formula, and select the corresponding emissivity function to measure the temperature of the target and obtain the corresponding measured temperature value T.

[0016] (5) Control the MEMS galvanometer to rotate and scan the position, measure the spectral information at different positions, obtain the corresponding spectral curves, and calculate the corresponding temperature field information. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the multispectral radiation temperature field measurement device based on a MEMS galvanometer according to the present invention.

[0018] Figure 2 This is a flowchart of the operation for multispectral radiation temperature field measurement based on MEMS galvanometers.

[0019] Figure 3 The flowchart shows the calculation process for multispectral radiation temperature field measurement based on MEMS galvanometers. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] To make the description of this disclosure more detailed and complete, illustrative descriptions of embodiments and specific examples of the present invention are provided below; however, these are not the only forms of implementing or utilizing the specific examples of the present invention. The embodiments cover features of multiple specific examples and methods and steps for constructing and operating these specific examples, and their order. However, other specific examples may also be used to achieve the same or equivalent functions and order of steps.

[0022] like Figure 1As shown, this multispectral radiation temperature field measurement device based on a MEMS galvanometer includes: a MEMS galvanometer scanning imaging device, a spectral information acquisition device 7, and a temperature field inversion information calculation device 8. The MEMS galvanometer scanning imaging device and the spectral information acquisition device are connected by optical fiber 6, and the spectral information acquisition device and the temperature field inversion information calculation device are electrically connected.

[0023] The scanning imaging device of MEMS galvanometers realizes the function of scanning imaging of temperature field through real-time control of 2D micro galvanometers and corresponding optical path calculation.

[0024] The spectral information acquisition device is used to acquire the spectral radiance information of a high-temperature object 1 being measured at a distance under different wavelength conditions. It uses an optical fiber coupling method to build a symmetrical Czerny-Turner structure optical path through a reflective blazed grating. The actual energy coupled into the optical fiber is spectrally dispersed, and then a detector is used to perform photoelectric information conversion on the dispersed spectrum to finally obtain the corresponding spectral curve.

[0025] The temperature field inversion information calculation device is used to amplify, filter, collect, process, and analyze the photoradiance signals of the target under different wavelengths obtained by the spectral information acquisition device, and calculate the corresponding target temperature by combining the spectral information.

[0026] This invention improves the calibration accuracy of traditional temperature measuring devices and methods by constructing a multispectral radiation temperature field measurement device based on MEMS galvanometers and the corresponding high-temperature measurement method. At the same time, it can more effectively overcome the measurement error caused by the inability to modify the wavelength selection in traditional temperature measuring devices by selecting detailed spectral information. It can solve the problem that current multispectral temperature measuring devices cannot dynamically select the corresponding energy parameters for calculation and optimizes the error generated in the calibration stage to improve measurement accuracy.

[0027] Preferably, the MEMS galvanometer scanning imaging device and spectral information acquisition device include: a MEMS micro-mirror and an imaging lens group 4;

[0028] The MEMS micro mirror includes: MEMS mirror lens 3 and MEMS mirror drive control module 2;

[0029] MEMS galvanometer lens enables two-dimensional vibration of the micro-mirror, controls the optical path to move the optical axis, and realizes the dynamic scanning function of the optical path; the MEMS galvanometer drive control module provides vibration energy and control signals to the MEMS galvanometer lens.

[0030] Preferably, the spectral information acquisition device includes: a spectral information calculation device, which obtains the spectral distribution curve of the object's position, obtains the spectral distribution of the target being measured, and determines the final required calculation wavelength based on the spectral curve characteristics of the target being measured; the spectral information calculation device selects a suitable calculation unit from the spectral curve for temperature calculation in order to reduce the error generated in the calculation process.

[0031] Preferably, the spectral information processing device further includes: an indium gallium arsenide APD photodetector, the indium gallium arsenide APD photodetector 5, used to detect and receive electromagnetic wave signals corresponding to the near-infrared band, and realize the function of converting infrared signals into electrical signals, which facilitates subsequent signal processing.

[0032] Preferably, the temperature field inversion information calculation device includes: a temperature information processing unit and a temperature field display unit; the temperature information processing unit performs algorithm correction on the collected data during the experimental calibration process and calculates the temperature field parameters; the temperature field display unit combines the real-time specific location information fed back by the MEMS galvanometer to perform temperature field calculation and imaging.

[0033] like Figure 2 As shown, a method for measuring the multispectral radiation temperature field based on a MEMS galvanometer is also provided, which includes the following steps:

[0034] (1) Align the MEMS galvanometer-based multispectral radiation temperature field measuring device with the standard high-temperature blackbody radiation furnace, reset the MEMS galvanometer, adjust the temperature of the high-temperature blackbody radiation furnace to a wavelength range suitable for the APD detector to respond well, and obtain the spectral curve information of the corresponding point.

[0035] (2) Use the wavelength characteristic inversion algorithm to obtain the wavelength and corresponding characteristic information after the algorithm optimization, and then calibrate it;

[0036] (3) Select six wavelengths and perform temperature calculations on the calibrated data respectively to obtain the corresponding spectral energy information calculated by the wavelength characteristic inversion algorithm, and calculate the calibration function model at the corresponding temperature.

[0037] (4) Substitute the calibration coefficient function into the formula, and select the corresponding emissivity function to measure the temperature of the target and obtain the corresponding measured temperature value T.

[0038] (5) Control the MEMS galvanometer to rotate and scan the position, measure the spectral information at different positions, obtain the corresponding spectral curves, and calculate the corresponding temperature field information.

[0039] like Figure 3As shown, preferably, in step (1), a highly sensitive response voltage signal curve can be obtained through the APD detector, and the obtained response curve relationship is A. i =f(λ) i The voltage signal curve can be obtained by fitting a high-order polynomial, and the corresponding fitted curve equation is: Where A i For the corresponding voltage amplitude, λ i For the corresponding wavelength.

[0040] Preferably, in step (2), by proposing a wavelength characteristic inversion algorithm, the wavelength information and corresponding feature information after algorithm optimization are obtained; in the pyrometer, according to Planck's blackbody radiation law, the theoretical energy intensity formula relationship that the pyrometer should obtain is as follows:

[0041] Where k i As a geometric calibration coefficient, it is used in the calibration process to unify the theoretical value with the actual measured value. For ε(λ) i The emissivity function (T) is a constant value of 1 for blackbody, but for actual measurement targets, the emissivity of gray body targets is difficult to determine due to the influence of wavelength and temperature. When calibrating the instrument using a high-temperature blackbody furnace, the wavelength characteristic inversion algorithm is used to reduce the calibration error caused by the low detection resolution bandwidth (FWHM) of traditional filter-based detection. At this time, the emissivity function is set to 1.

[0042] The theoretical relationship between the measured value and the theoretical value during the calibration process is f(λ). i ) = G i I i Let the selected wavelength be λ1, then λ1 satisfies the following relationship: The wavelength eigenvalues ​​selected in the region adjacent to wavelength λ1 are λ. 1-α , λ 1+α and its corresponding strength I 1+α I 1-α , where α < 2;

[0043] The expected value at the corresponding wavelength is calculated to obtain the theoretical expected value at wavelength λ1 with α as the inversion radius; the theoretical expected value is... Simplify the calculation results. but This is the theoretical value calculated after inversion of the wavelength characteristics corresponding to wavelength λ1.

[0044] Preferably, in step (3), the six wavelengths selected for calculation are λ. i If (i = 1, 2, ..., 6) is used for actual calculation and calibration, then The average of the calculated calibration coefficients is used as the final calibration constant coefficient. Substituting the calibrated constant coefficient values ​​into the actual temperature measurement formula, we obtain the calibrated temperature measurement formula as follows:

[0045] Preferably, in step (4), the emissivity function model is selected as follows: The measurement results at six wavelengths are combined with the emissivity function to solve for the temperature T to be measured. Substituting these results into the equations yields the following system of equations:

[0046]

[0047] The unknown parameter is the emissivity model ε. i There are seven unknowns (i = 1, 2, ... 6) and T. Solving the system of equations yields the calculated results of the corresponding emissivity and temperature T.

[0048] In step (5), temperature information at different locations is obtained by controlling different motion states of the MEMS galvanometer. Temperature information of the corresponding temperature field is obtained through the actual situation of the MEMS motion state equation, and the temperature field inversion solution is realized.

[0049] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention. Specific Implementation Example 1:

[0051] The basic operating procedure of this invention is as follows: Figure 2 As shown, the basic architecture of the multispectral radiation temperature field measurement device based on MEMS galvanometers is as follows: Figure 1 As shown.

[0052] Step 1: Place the MEMS galvanometer-based multispectral radiation temperature field measurement device 5 meters away from the high-temperature blackbody furnace, reset the MEMS galvanometer, start the temperature measurement device, adjust the temperature of the high-temperature blackbody radiation furnace to 1500K, and obtain the spectral curve information of the corresponding point.

[0053] Step 2: Select the input calculation wavelength as 650, 750, 850, 800, 950, 1050, or 1100 nm. Click the control software to start the wavelength characteristic inversion algorithm calculation software, and obtain the corresponding calculation results and feedback calibration parameters;

[0054] Step 3: Perform temperature calculations on the calibrated data to obtain the calibration function model at the corresponding temperature;

[0055] Step 4: Substitute the coefficients into the function model formula, select the corresponding emissivity function, align the device with the target object, keep the MEMS galvanometer position unchanged, measure the temperature of the target object, and obtain the corresponding measured temperature value T.

[0056] Step 5: Control the MEMS galvanometer to rotate and scan the position, measure the spectral information at different positions, and calculate the corresponding temperature field information. Specific Implementation Example 2:

[0058] Taking the selection of six effective wavelengths of 650, 750, 850, 800, 950, 1050, and 1100 nm as an example, the calculation flowchart is as follows: Figure 3 As shown.

[0059] Step 1: After fitting with a higher-order function, the corresponding fitted curve equation is obtained as follows: Where A i For the corresponding voltage amplitude, λ i For the corresponding wavelength.

[0060] Step 2: Set the emissivity function to 1. The theoretical relationship between the measured value and the theoretical value during the calibration process is f(λ). i ) = G i I i The selected wavelength is 650nm, which satisfies the relationship... The wavelength eigenvalues ​​selected in the adjacent region of wavelength 650nm are 648nm and 652nm, and their corresponding intensities I are... 648 I 652 Where α < 2. The expected value at the corresponding wavelength is calculated to obtain the theoretical expected value at a wavelength of 650 nm with an inversion radius of 2 nm. The theoretical expected value is... The calculation results are obtained but The theoretical value is the wavelength characteristic inversion calculation corresponding to a wavelength of 650nm.

[0061] Step 3: Perform actual calculations and calibrations using the six wavelengths selected for calculation: 650nm, 750nm, 850nm, 800nm, 950nm, 1050nm, and 1100nm.

[0062] The average value of the calculated calibration coefficients is taken as the final calibration constant coefficient, i.e. Substituting the calibrated constant coefficient values ​​into the actual temperature measurement formula, we obtain the calibrated temperature measurement formula as follows:

[0063] By adding a wavelength characteristic inversion algorithm during the calibration process, data processing of the system coefficients before calibration was achieved, thereby improving the accuracy of the calibration process.

[0064] Step 4: Select the emissivity function model as By solving the measurements at six wavelengths together with the emissivity function, the measured temperature T can be obtained. Substituting these values ​​into the equations, we get the following system of equations:

[0065]

[0066] The unknown parameter is the emissivity model ε. i There are seven unknowns (i = 1, 2, ... 6) and T. Solving the system of equations simultaneously will yield the calculated results of the corresponding emissivity and temperature T.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A multispectral radiation temperature field measurement device based on a MEMS galvanometer, characterized in that: It includes: The system comprises a MEMS galvanometer scanning imaging device, a spectral information acquisition device, and a temperature field inversion information calculation device. The MEMS galvanometer scanning imaging device and the spectral information acquisition device are connected by optical fiber coupling, and the spectral information acquisition device and the temperature field inversion information calculation device are electrically connected. The MEMS galvanometer scanning imaging device achieves temperature field scanning imaging function through real-time control of 2D micro-mirrors and corresponding optical path calculation. The spectral information acquisition device is used to acquire the spectral radiance information of a distant target under different wavelength conditions. It uses an optical fiber coupling method to build a symmetrical Czerny-Turner structure optical path through a reflective blazed grating. The actual energy coupled into the optical fiber is spectrally dispersed, and then a detector is used to perform photoelectric information conversion on the dispersed spectrum to finally obtain the corresponding spectral curve. The temperature field inversion information calculation device is used to amplify, filter, collect, process, and analyze the photoradiance signals of the target under different wavelengths obtained by the spectral information acquisition device, and calculate the corresponding target temperature in combination with the spectral information. The MEMS galvanometer scanning imaging device and spectral information acquisition device include: a MEMS micro-mirror and an imaging lens group; MEMS micro mirrors include: MEMS mirror lens and MEMS mirror drive control module; MEMS galvanometer lens enables two-dimensional vibration of the micro-mirror, controls the optical path to move the optical axis, and realizes the dynamic scanning function of the optical path; the MEMS galvanometer drive control module provides vibration energy and control signals to the MEMS galvanometer lens. The spectral information acquisition device includes: a spectral information calculation device, which obtains the spectral distribution curve of the object's position, obtains the spectral distribution of the target being measured, and determines the final required calculation wavelength based on the spectral curve characteristics of the target being measured; the spectral information calculation device selects a suitable calculation unit from the spectral curve for temperature calculation in order to reduce the error generated in the calculation process. The spectral information processing device also includes: an indium gallium arsenide APD photodetector, which is used to detect and receive electromagnetic wave signals corresponding to the near-infrared band, and realize the function of converting infrared signals into electrical signals to facilitate subsequent signal processing. The temperature field inversion information calculation device includes a temperature information processing unit and a temperature field display unit. The temperature information processing unit performs algorithm correction on the collected data and calculates the temperature field parameters during the experimental calibration process. The temperature field display unit combines the real-time specific location information fed back by the MEMS galvanometer scanning imaging device to perform temperature field calculation and imaging.

2. The method for measuring the temperature field of a multispectral radiation field based on a MEMS galvanometer according to claim 1, characterized in that: It includes the following steps: (1) Align the MEMS galvanometer-based multispectral radiation temperature field measuring device with the standard high-temperature blackbody radiation furnace, reset the MEMS galvanometer scanning imaging device, adjust the temperature of the high-temperature blackbody radiation furnace to a wavelength range suitable for the APD detector to respond well, and obtain the spectral curve information of the corresponding point. (2) Use the wavelength characteristic inversion algorithm to obtain the wavelength and corresponding feature information after the algorithm optimization, and then calibrate it; (3) Select six wavelengths and perform temperature calculations on the calibrated data respectively to obtain the corresponding spectral energy information calculated by the wavelength characteristic inversion algorithm, and calculate the calibration function model at the corresponding temperature; (4) Substitute the calibration coefficient function into the formula, and at the same time select the corresponding emissivity function to measure the temperature of the target and obtain the corresponding measured temperature value T; (5) Control the MEMS galvanometer lens to rotate and scan the position, measure the spectral information at different positions, obtain the corresponding spectral curves, and calculate the corresponding temperature field information.

3. The method for measuring the temperature field of a multispectral radiation field based on a MEMS galvanometer according to claim 2, characterized in that: In step (1), a highly sensitive response voltage signal curve can be obtained through the APD detector, and the relationship of the obtained response voltage signal curve is as follows: The response voltage signal curve is obtained by fitting a high-order polynomial, and the corresponding fitted curve equation is: ,in For the corresponding voltage amplitude, , For the corresponding wavelength.

4. The method for measuring the multispectral radiation temperature field based on a MEMS galvanometer according to claim 3, characterized in that: In step (2), by proposing a wavelength characteristic inversion algorithm, the wavelength information and corresponding feature information after algorithm optimization are obtained; in the pyrometer, according to Planck's blackbody radiation law, the theoretical energy intensity formula relationship that the pyrometer should obtain is as follows: , in As a geometric calibration coefficient, it is used in the calibration process to unify the theoretical value with the actual measured value. As an emissivity function, it is a constant value of 1 for a blackbody. However, for actual targets, the emissivity of gray body targets is difficult to determine due to the influence of wavelength and temperature. When calibrating the instrument using a high-temperature blackbody furnace, the wavelength characteristic inversion algorithm is used to reduce the calibration error caused by the low detection resolution bandwidth FWHM of traditional filter-based detection. At this time, the emissivity function is set to 1. The theoretical relationship between the measured value and the theoretical value during the calibration process is as follows: Let the selected wavelength be... ,but Satisfying the relation Choose at wavelength The wavelength eigenvalues ​​of adjacent domains are respectively , and their corresponding strength , ,in ; Calculate the expected value at the corresponding wavelength to obtain the value at a wavelength of ,by As the inversion radius; the theoretical expected value is Simplify the calculation results. ,but For the corresponding wavelength The theoretical value after inversion calculation of the corresponding wavelength characteristics.

5. The method for measuring the multispectral radiation temperature field based on a MEMS galvanometer according to claim 4, characterized in that: In step (3), the six wavelengths selected for calculation are respectively Perform actual calculations and calibrations, then The average value of the calculated calibration coefficients is taken as the final calibration constant coefficient. Substituting the calibrated constant coefficient values ​​into the actual temperature measurement formula, we obtain the calibrated temperature measurement formula as follows: .

6. The method for measuring the multispectral radiation temperature field based on a MEMS galvanometer according to claim 5, characterized in that: In step (4), the emissivity function model is selected as... The measurement results of the six wavelengths are combined with the emissivity function to solve for the temperature T to be measured. Substituting these results into the equations, we obtain the following system of equations: ， The unknown parameter is the emissivity. and There are seven unknowns. Solving the system of equations yields the corresponding emissivity and temperature. The calculation results; In step (5), temperature information at different locations is obtained by controlling different motion states of the MEMS galvanometer. Temperature information of the corresponding temperature field is obtained through the actual situation of the MEMS motion state equation, and the temperature field inversion solution is realized.

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