Temperature measuring method and device and storage medium

Abstract

The invention provides a temperature measurement method and device and a storage medium, and the method comprises the steps: measuring the absorbance of a sample to pulse laser at different temperatures through a measurement system, and obtaining a relation curve between the temperature and the absorbance; correcting the original Green Nesson coefficient by using a correction term of the Green Nesson coefficient in the opto-acoustic field to obtain an absorption intensity-opto-acoustic excitation intensity calculation formula between the absorbance and the acoustic wave intensity; further substituting into a curve that the absorbance changes along with the temperature under the wavelength to obtain a sound wave intensity-temperature fitting formula of the target to be subjected to temperature measurement; and substituting the ROI signal after image reconstruction by using a photoacoustic reconstruction algorithm into a sound wave intensity-temperature fitting formula to obtain the temperature of the target to be subjected to temperature measurement. According to the method, based on the photoacoustic effect, the temperature measurement precision is improved on the basis of achieving accurate temperature measurement of the deep tissue (3-5 cm).

Description

Technical Field

[0001] The present application relates to the field of temperature measurement technology, and in particular to a temperature measurement method, device and storage medium. Background Art

[0002] Existing temperature measurement technologies mainly include contact temperature measurement technology, infrared temperature measurement technology, and acoustic temperature measurement technology. The traditional contact temperature measurement method requires direct contact with the object being measured, which is complicated to operate and cannot achieve real-time monitoring; although infrared temperature measurement technology does not require contact, it can only measure surface temperature and has limited penetration depth; although acoustic temperature measurement technology can obtain deep temperature information to a certain extent, its accuracy is often low and is easily affected by the characteristics of the medium.

[0003] In other words, the measurement accuracy of current temperature measurement technology is not high enough. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a temperature measurement method, device and storage medium. The method is based on the photoacoustic effect and can improve the accuracy of temperature measurement.

[0005] In the first aspect, an embodiment of the present application provides a temperature measurement method, comprising: using a measurement system to measure the absorbance of a sample to a pulsed laser at different temperatures, and obtaining a relationship curve between temperature and absorbance; using a correction term of the Grignard coefficient in the field of photoacoustics to correct the original Grignard coefficient, and obtaining an absorption intensity-photoacoustic excitation intensity calculation formula between absorbance and sound wave intensity; further substituting the absorbance versus temperature curve at this wavelength to obtain a sound wave intensity-temperature fitting formula for the target to be measured; and using a photoacoustic reconstruction algorithm to reconstruct the image, the ROI area signal is substituting the sound wave intensity-temperature fitting formula to obtain the temperature of the target to be measured.

[0006] The above-mentioned temperature measurement method is based on the photoacoustic effect, and removes the absorption singularity in the relationship curve between temperature and absorbance, in which the sample temperature is insensitive to the change in absorbance, so as to correct the deviation of the relationship curve between the temperature and absorbance. It avoids the problems of invasive operation and limited measurement depth that may be caused by contact temperature measurement. Since the laser can effectively penetrate opaque or highly scattering materials, the method provided in the embodiment of the present application can measure the deep temperature more accurately, avoiding the measurement error caused by the difference between the surface temperature and the internal temperature. In addition, since the high energy density of the laser can effectively irradiate the target object and generate a clear sound wave signal, the signal-to-noise ratio of the measurement is improved, and the interference of the external environment on the measurement is reduced, that is, the accuracy of the temperature measurement is improved.

[0007] In combination with the first aspect, optionally, the method of using a measurement system to measure the absorbance of a sample to a pulsed laser at different temperatures and obtaining a relationship curve between temperature and absorbance includes: using a spectrophotometer to measure the absorption spectrum of the sample at different temperatures; and determining the relationship curve between temperature and absorbance based on the absorption spectrum.

[0008] The above temperature measurement method improves the accuracy of data acquisition by using a spectrophotometer to measure the absorption spectrum of the sample at different temperatures, and determines the relationship curve between temperature and absorbance based on the absorption spectrum, thereby obtaining a higher resolution relationship curve. In addition, by recording and analyzing the absorption spectrum at different temperatures, a detailed data archive can be obtained, which facilitates future research and verification.

[0009] In combination with the first aspect, optionally, after using the measurement system to measure the absorbance of the sample to the pulsed laser at different temperatures and obtaining the relationship curve between the temperature and the absorbance, the method further includes: using the absorption singular point in the relationship curve where the sample temperature is insensitive to the change in absorbance to correct the error of the test system; wherein the error includes the systematic error of the laser energy stability and the temperature control device and the gross error of the measurement; the absorption singular point is a point where the maximum absorption difference is less than 0.001abs, and the maximum temperature difference in the temperature range during the correction of the test system does not exceed the temperature difference threshold of the test system.

[0010] The above temperature measurement method further improves the accuracy of the measurement result by removing the absorption singular points that are not affected by temperature changes and correcting the absorbance fluctuation caused by temperature changes.

[0011] In combination with the first aspect, optionally, the use of absorption singular points in the relationship curve where the sample temperature is insensitive to changes in absorbance to correct the errors of the test system includes: using the absorption singular points to perform normalization correction on the absorption intensity range; correcting the laser energy stability; correcting the system errors of the temperature control device; and correcting gross errors in the measurement.

[0012] The above temperature measurement method eliminates absorbance fluctuations caused by temperature changes by performing absorption zero correction, correcting laser energy stability, correcting system errors of temperature control devices, and correcting gross measurement errors, thereby further improving the accuracy and reliability of temperature measurement.

[0013] In combination with the first aspect, optionally, the method of using the correction term of the Grignard coefficient in the field of photoacoustics to correct the original Grignard coefficient to obtain the absorption intensity-photoacoustic excitation intensity calculation formula between absorbance and sound wave intensity includes: using the correction term of thermal saturation caused by absolute temperature (AT) changes in the field of photoacoustics to correct the original photoacoustics (Grignard formula) to obtain the photoacoustic dynamic formula in the photoacoustic excitation-absolute temperature change correction formula and the dynamic correction term introduced by the absolute temperature change; wherein, The dynamic correction term introduced by the absolute temperature change is: ; The corrected photoacoustic dynamic correction formula is: ; In the formula, is the correction term due to absolute temperature change, λ i is the wavelength, μ a is the light absorption coefficient, p 0 is the corrected photoacoustic pressure, F pulse is the light flux of a single pulse, b is a constant that at least characterizes the physical properties of the sample material and the measurement system, is the thermal relaxation time constant, is the thermal energy conversion efficiency, is the base Gruenneisen coefficient, is the time interval between pulses of the pulsed laser; The dynamic correction formula, the light source parameters of the pulsed laser, the normalization coefficient obtained from the singular point, the energy correction parameters of the test system, and the temperature control compensation parameters are substituted into the photoacoustic excitation intensity formula to obtain the absorption intensity-photoacoustic excitation intensity calculation formula.

[0014] The above-mentioned temperature measurement method corrects the original Grignard formula by using the correction term of the Grignard coefficient in the photoacoustic field, and substitutes the obtained dynamic correction formula together with the light source parameters of the pulsed laser and the absorption zeroing coefficient into the photoacoustic excitation intensity formula. The final absorption intensity-photoacoustic excitation intensity calculation formula further improves the accuracy of temperature measurement.

[0015] In combination with the first aspect, optionally, the ROI area signal after image reconstruction using the photoacoustic reconstruction algorithm is brought into the temperature measurement calculation formula to obtain the temperature of the target to be measured, including: using the image reconstruction algorithm to reconstruct the image of the acoustic wave signal generated by the target to be measured when absorbing the pulse laser, to obtain a photoacoustic intensity image slice of the target to be measured; and determining the region of interest of the photoacoustic intensity image slice, and using the absorption intensity-photoacoustic excitation intensity calculation formula to calculate the temperature of the region of interest, to obtain the temperature distribution of the region of interest.

[0016] The above-mentioned temperature measurement method, by using an image reconstruction algorithm to determine the photoacoustic intensity image slice and calculate the temperature distribution of the area of ​​interest in the photoacoustic intensity image slice, not only further improves the accuracy and reliability of the measurement results, but also provides more intuitive and comprehensive temperature information.

[0017] In combination with the first aspect, optionally, measuring the temperature of the target to be measured according to the acoustic wave intensity of the target to be measured and the absorption intensity-photoacoustic excitation intensity calculation formula also includes: real-time correction based on the propagation rate of the acoustic wave signal generated by the sample in the process of absorbing the pulse laser measured by the acoustic wave conductor; using the image reconstruction algorithm to reconstruct the image of the acoustic wave signal generated in the process of the target to be measured absorbing the pulse laser to obtain the photoacoustic intensity image slice of the target to be measured, including: using the image reconstruction algorithm and the propagation rate of the wave signal to reconstruct the image of the acoustic wave signal generated in the process of the target to be measured absorbing the pulse laser to obtain the photoacoustic intensity image slice.

[0018] The above-mentioned temperature measurement method calibrates the propagation speed of the acoustic wave signal at multiple temperatures that need to be measured, and introduces the propagation speed of the acoustic wave signal in the process of correcting the image reconstruction size, thereby further improving the accuracy of the reconstructed image size, thereby further improving the accuracy of the final measured temperature.

[0019] In the second aspect, the present application provides a temperature measuring device, including a controller, an acoustic wave sensor, a temperature sensor, a laser emitting assembly, a cuvette, a temperature control assembly and a housing; an acoustic wave coupling agent that is nearly isotropic with the sample to be measured is arranged in the housing; the cuvette is located in the housing and immersed in the acoustic wave coupling agent; the cuvette is used to accommodate the sample; the cuvette material is made of a uniform and highly transmittance material that is nearly isotropic with the sample to be measured; the laser emitting assembly is located in the housing and electrically connected to the controller; the laser output end of the laser emitting assembly faces the cuvette and is used to emit a pulsed laser to the cuvette; the acoustic wave sensor is located in the housing and electrically connected to the controller; the acoustic wave collection end of the acoustic wave sensor faces the cuvette and is used to collect acoustic wave signals from the cuvette; the temperature sensor The device is located in the cuvette and is electrically connected to the controller; the temperature sensor is used to collect the temperature of the sample; the temperature control end of the temperature control component is located in the housing and is immersed in the acoustic wave coupling agent; the temperature control component is electrically connected to the controller; the controller is used to: use the measurement system to measure the absorbance of the sample to the pulsed laser at different temperatures, and obtain the relationship curve between temperature and absorbance; use the correction term of the Grignard coefficient in the photoacoustic field to correct the original Grignard coefficient, and obtain the absorption intensity-photoacoustic excitation intensity calculation formula between absorbance and acoustic wave intensity; further bring in the absorbance versus temperature curve at this wavelength to obtain the acoustic wave intensity-temperature fitting formula of the target to be measured; and use the photoacoustic reconstruction algorithm to reconstruct the ROI area signal after the image is reconstructed into the acoustic wave intensity-temperature fitting formula to obtain the temperature of the target to be measured.

[0020] The above-mentioned temperature measuring device has the same beneficial effects as the temperature measuring method provided by the above-mentioned first aspect, or any optional implementation manner of the first aspect, and will not be described in detail here.

[0021] In combination with the second aspect, optionally, the temperature control component includes a constant temperature medium container, a heat conductive part and a pipeline; the constant temperature medium container contains a constant temperature medium and is electrically connected to the controller; the heat conductive part has a flow channel for the constant temperature medium to flow, and is located in the outer shell and immersed in the acoustic wave coupling agent; the heat conductive part is connected to the constant temperature medium container through the pipeline; the constant temperature medium container is configured to adjust the temperature of the constant temperature medium under the control of the controller, and allow the constant temperature medium to flow through the flow channel of the heat conductive part.

[0022] The temperature measuring device described above, by forming a temperature control component with a constant temperature medium container, a heat conducting member and a pipeline, not only realizes the control of the temperature of the colorimetric dish and the sample, but also simplifies the structure of the temperature control component.

[0023] In combination with the second aspect, optionally, the laser emitting assembly includes a laser and a combination lens; the laser is electrically connected to the controller and is used to emit pulsed laser under the control of the controller; the combination lens is located on the optical path of the laser emitted by the laser and is used to shape the laser emitted by the laser.

[0024] The temperature measuring device above shapes the pulse laser emitted by the laser through a combined lens, thereby ensuring the precise irradiation of the pulse laser on the sample, thereby further improving the accuracy of temperature measurement.

[0025] In a third aspect, an embodiment of the present application further provides a storage medium, which includes a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method described above is executed.

[0026] The above-mentioned storage medium has the same beneficial effects as the temperature measurement method provided by the above-mentioned first aspect, or any optional implementation manner of the first aspect, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A first flow chart of a temperature measurement method provided in an embodiment of the present application;

[0029] Figure 2 A specific flow chart of step S120 in the temperature measurement method provided in an embodiment of the present application;

[0030] Figure 3 A second flow chart of the temperature measurement method provided in the embodiment of the present application;

[0031] Figure 4 A specific flow chart of step S130 in the temperature measurement method provided in an embodiment of the present application;

[0032] Figure 5 A specific flow chart of step S140 in the temperature measurement method provided in an embodiment of the present application;

[0033] Figure 6 A specific flow chart of step S180 in the temperature measurement method provided in an embodiment of the present application;

[0034] Figure 7 A schematic diagram of the structure of a temperature measuring device provided in an embodiment of the present application;

[0035] Figure 8 A three-dimensional diagram of a temperature measuring device provided in another embodiment of the present application.

[0036] Icons: 100, temperature measuring device; 110, controller; 120, acoustic wave sensor; 130, temperature sensor; 140, laser emitting assembly; 141, laser; 142, combined lens; 150, cuvette; 160, temperature control assembly; 161, constant temperature medium container; 162, heat conductor; 163, pipeline; 170, housing; 180, acoustic wave coupling agent; 1, constant temperature circulating liquid pipeline connector; 2, photoacoustic probe fixing device; 3, constant temperature circulating liquid pipeline; 4, housing 5, upper plate 6, photoacoustic probe; 7, sample fixture; 8, sample cuvette. DETAILED DESCRIPTION

[0037] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0039] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0040] The following is a brief description of the main temperature measurement technologies currently used.

[0041] Regarding contact temperature measurement technology, it mainly uses contact sensors such as thermocouples and thermistors, which usually need to directly contact the surface of the object being measured. However, the temperature of deep tissues or internal objects cannot be directly measured by simple contact, and invasive operations (such as inserting probes) are required, which may cause tissue damage or contamination.

[0042] Regarding infrared temperature measurement in contact technology, it can only measure surface temperature and cannot penetrate obstructions or measure deep tissues.

[0043] Regarding laser Raman scattering temperature measurement in contact technology, it is suitable for gas or transparent liquid, but it is difficult to apply in complex media or opaque environments.

[0044] Regarding the acoustic temperature measurement in contact technology, although it can obtain deep temperature information to a certain extent, its resolution is low and it is easily affected by environmental noise and medium characteristics.

[0045] Regarding traditional optical imaging based imaging techniques, the penetration depth of light in opaque or scattering media is limited and is usually insufficient to obtain deep temperature distribution.

[0046] Regarding ultrasonic imaging based on imaging technology, ultrasound can penetrate to a certain depth, but lacks a signal mechanism directly related to temperature, making accurate temperature measurement difficult.

[0047] In view of this, the present application provides a temperature measurement method, device and storage medium to solve the above technical problems. It mainly realizes the temperature measurement of the target to be measured based on the photoacoustic effect. The photoacoustic effect is a phenomenon that when a substance absorbs light energy (pulsed laser), part of the energy is converted into heat energy, causing local temperature rise and volume expansion, and generating sound waves. Photoacoustic imaging technology (PAI) is based on the principle of converting light energy into sound energy, and uses thermoelastic sound waves after pulsed laser excitation to detect and image the internal structure and properties of samples (various materials and biological tissues). Current photoacoustic devices analyze the differences in sound wave signals generated by materials to obtain the type and spatial distribution of substances inside the object, while ignoring the correlation between sound wave intensity and temperature.

[0048] The application of photoacoustic effect involves two processes. First, the sample absorbs the energy of pulsed light. In a short period of time, the sample expands due to heat, realizing the conversion of light energy into thermal energy. Then, the sample expands and contracts due to heat and vibration, generating sound waves, realizing the conversion of thermal energy into acoustic energy. Changes in temperature will change the changes in parameters such as the light absorption coefficient of the sample, thereby affecting the conversion of light energy into thermal energy. Temperature changes will also affect the sample's volume thermal expansion coefficient, heat capacity under constant pressure and other parameters, further affecting the conversion of thermal energy into acoustic energy. After research, it was found that the relationship between temperature changes and parameters such as the sample's light absorption coefficient and volume thermal expansion coefficient satisfies the following formula:

[0049]

[0050] P represents the intensity of the sound waves generated by the sample, F represents the local light flux, μ a represents the light absorption coefficient, β represents the volume thermal expansion coefficient, V l represents the longitudinal wave speed and C pis the heat capacity at constant pressure. Γ is the Grüneison parameter. The Grüneison parameter (which depends on the isothermal compressibility of the sample, the volumetric thermal expansion coefficient, the mass density and the specific heat capacity at constant volume) varies significantly with temperature.

[0051] For details, please refer to the various embodiments and drawings provided in this application.

[0052] Please refer to Figure 1 , Figure 1 This is a first flow chart of the temperature measurement method provided in the embodiment of the present application. The temperature measurement method provided in the embodiment of the present application may include:

[0053] Step S120: using a measurement system to measure the absorbance of the sample to the pulsed laser at different temperatures, and obtaining a relationship curve between temperature and absorbance.

[0054] In the above step S120, the sample can be water. By controlling the laser emission component in the measurement system to emit pulsed laser to the sample, the absorption of the pulsed laser by the sample at different temperatures can be measured by the optical sensor. Thus, a relationship curve between temperature and absorbance can be obtained to understand the light absorption characteristics of the sample at different temperatures.

[0055] Step S140: The original Grignard coefficient is corrected using the correction term of the Grignard coefficient in the photoacoustic field to obtain the absorption intensity-photoacoustic excitation intensity between the absorbance and the sound wave intensity.

[0056] In the above step S140, the correction term of the Grignard coefficient in the field of photoacoustics is used to describe the relationship between the absorption of laser energy and the generation of sound waves in the photoacoustic effect. After correction, the photoacoustic effect of the object can be more accurately reflected.

[0057] Step S160: further bring in the absorbance-temperature curve at this wavelength to obtain the sound wave intensity-temperature fitting formula of the target to be measured.

[0058] In the above step S160, the temperature of the target to be measured can be obtained by detecting the intensity of the sound waves generated by the target to be measured based on the photoacoustic effect and combining it with the absorption intensity-photoacoustic excitation intensity calculation formula obtained above.

[0059] Step S180: Use the photoacoustic reconstruction algorithm to reconstruct the ROI area signal and bring it into the sound wave intensity-temperature fitting formula to obtain the temperature of the target to be measured.

[0060] In the above implementation process, based on the photoacoustic effect, the absorption singularity in which the sample temperature is insensitive to the change of absorbance in the relationship curve between temperature and absorbance is removed to correct the relationship curve between temperature and absorbance. The problems of invasive operation and limited measurement depth that may be caused by contact temperature measurement are avoided. Since the laser can effectively penetrate opaque or highly scattering materials, the method provided in the embodiment of the present application can measure deep temperature more accurately, avoiding measurement errors caused by the difference between surface temperature and internal temperature. In addition, since the high energy density of the laser can effectively irradiate the target object and generate a clear sound wave signal, the signal-to-noise ratio of the measurement is improved, and the interference of the external environment on the measurement is reduced, that is, the accuracy of temperature measurement is improved.

[0061] Please refer to Figure 2 , Figure 2 is a specific flow chart of step S120 in the temperature measurement method provided in the embodiment of the present application. In some optional implementations, step S120 may include:

[0062] Step S121: using a spectrophotometer to measure the absorption spectra of the samples at different temperatures.

[0063] Step S122: determining a relationship curve between temperature and absorbance according to the absorption spectrum.

[0064] In the above steps, the optical sensor that can be used specifically can be a spectrophotometer. The spectrophotometer can be used to measure the absorption spectrum of the sample to the pulsed laser. Based on the absorption spectrum, the relationship curve between temperature and absorbance can be determined.

[0065] In the above implementation process, the absorption spectrum of the sample at different temperatures is measured by using a spectrophotometer, and the relationship curve between temperature and absorbance is determined based on the absorption spectrum, thereby improving the accuracy of data acquisition, thereby obtaining a higher resolution relationship curve. In addition, by recording and analyzing the absorption spectrum at different temperatures, a detailed data archive can be obtained, which is convenient for future research and verification.

[0066] Please refer to Figure 3 , Figure 3 This is a second flow chart of the temperature measurement method provided in the embodiment of the present application. After step S120, the temperature measurement method provided in the embodiment of the present application may further include:

[0067] Step S130: using the absorption singular point in the relationship curve where the sample temperature is insensitive to the change in absorbance to correct the error of the test system.

[0068] In the above step S130, the error includes the system error of the laser energy stability and the temperature control device and the gross error of the measurement; the absorption singular point is the point where the maximum absorption difference is less than 0.001abs, and the maximum temperature difference of the temperature range during the calibration test system does not exceed the temperature difference threshold of the test system. In the process of temperature change, it can usually be found that some absorption points do not change with temperature changes (i.e., temperature-insensitive absorption intersections), and these intersections can be used for absorption zeroing correction, for example: the absorption of water by a laser with a wavelength of 1003.4nm. By removing the absorption singular points that are not affected by temperature changes and correcting the absorbance fluctuations caused by temperature changes, the measurement results can be made more accurate.

[0069] In the above implementation process, the absorption singular points that are not affected by temperature changes are removed and the absorbance fluctuation caused by temperature changes is corrected, thereby further improving the accuracy of the measurement results.

[0070] Please refer to Figure 4 , Figure 4 is a specific flow chart of step S130 in the temperature measurement method provided in the embodiment of the present application. In some optional implementations, step S130 may include:

[0071] Step S131: using the absorption singular point to perform absorption intensity range normalization correction.

[0072] In the above step S131, illustratively, at a wavelength of 1003.4 nm, the absorbance of water remains constant within a temperature range of -6°C to 30°C. When measuring the absorbance of a sample within this temperature range, if it is found that the absorbance fluctuates with temperature, the absorbance at 1003.4 nm can be used as a reference point to remove these fluctuations, thereby achieving absorption zero correction.

[0073] Step S132: calibrate the laser energy stability.

[0074] Step S133: Correcting the system error of the temperature control device.

[0075] Step S134: Correcting the gross measurement error.

[0076] In the above implementation process, the absorbance fluctuation caused by temperature change is eliminated by performing absorption zero correction, correcting the laser energy stability, correcting the system error of the temperature control device, and correcting the gross error of the measurement, thereby further improving the accuracy and reliability of temperature measurement.

[0077] Please refer to Figure 5 , Figure 5is a specific flow chart of step S140 in the temperature measurement method provided in the embodiment of the present application. In some optional implementations, step S140 may include:

[0078] Step S141: using the correction term of thermal saturation caused by absolute temperature (AT) changes in the photoacoustic field to correct the original photoacoustic (Gruneisen formula), to obtain the photoacoustic dynamic formula in the photoacoustic excitation-absolute temperature change correction formula and the dynamic correction term introduced by the absolute temperature change; wherein, The dynamic correction term introduced by the absolute temperature change is: ; The corrected photoacoustic dynamic correction formula is: ; In the formula, is the correction term due to absolute temperature change, λ i is the wavelength, μ a is the light absorption coefficient, p 0 is the corrected photoacoustic pressure, F pulse is the light flux of a single pulse, b is a constant that at least characterizes the physical properties of the sample material and the measurement system, is the thermal relaxation time constant, is the thermal energy conversion efficiency, is the base Gruenneisen coefficient, is the time interval between pulses of a pulsed laser.

[0079] In the above step S141, the formula of the original Grinneison parameter is as follows:

[0080]

[0081] Step S142: Substitute the dynamic correction formula, the light source parameters of the pulsed laser, the normalization coefficient obtained from the singular point, the energy correction parameters of the test system, and the temperature control compensation parameters into the photoacoustic excitation intensity formula to obtain the absorption intensity-photoacoustic excitation intensity calculation formula.

[0082] In the above step S142, the light source parameters of the pulsed laser can be obtained from the factory parameters of the laser emitting component, and the absorption zeroing parameters are obtained from the previous steps S131 to S134.

[0083] In the above implementation process, the original Grignard coefficient is used to correct the original Grignard coefficient in the field of photoacoustics, and the obtained dynamic correction formula is substituted into the photoacoustic excitation intensity formula together with the light source parameters of the pulsed laser and the absorption zeroing coefficient. The final absorption intensity-photoacoustic excitation intensity calculation formula further improves the accuracy of temperature measurement.

[0084] Please refer to Figure 6 , Figure 6 is a specific flow chart of step S180 in the temperature measurement method provided in the embodiment of the present application. In some optional implementations, step S180 may include:

[0085] Step S181: reconstructing the image of the acoustic wave signal generated by the temperature target absorbing the pulsed laser by using an image reconstruction algorithm to obtain a photoacoustic intensity image slice of the temperature target.

[0086] In the above step S181, the DAS or BP algorithm can be used to reconstruct the photoacoustic signal to obtain a photoacoustic intensity image slice of the object section, from which it can be seen that the photoacoustic intensity is positively correlated with the temperature.

[0087] Among them, regarding the DAS algorithm, its specific process can be:

[0088] 1. Collect photoacoustic signals: Collect photoacoustic signals from multiple detectors (sensors).

[0089] 2. Delay correction: Perform time delay correction on the signal based on the distance between each detector and each point in the imaging area.

[0090] 3. Weighted sum of signals: The signal at each location is weighted and summed (i.e., the signals of all detectors are superimposed after delay).

[0091] 4. Image reconstruction: Map the weighted sum result to the image space to obtain the temperature or signal intensity distribution of the imaging area.

[0092] The theoretical formula on which it is based can be:

[0093]

[0094] In the formula, represents the signal received by the i-th detector, is the time calculated based on the propagation time delay.

[0095] Delay The calculation formula is:

[0096]

[0097] In the formula, is the detector position, is the imaging point position, It is the speed of sound.

[0098] Regarding the BP (Back Projection) image reconstruction algorithm, its specific process can be:

[0099] 1. Collect photoacoustic signals: Collect photoacoustic signals from multiple detectors.

[0100] 2. Signal projection into image space: The signal of each detector is back-projected into the image space and its contribution to the imaging area is calculated.

[0101] 3. Image accumulation: The results of the reverse projection of each detector are accumulated to obtain the final image.

[0102] 4. Image reconstruction: Finally, the temperature or signal intensity distribution of each point in the area is obtained.

[0103] The theoretical formula on which the BP algorithm is based is:

[0104]

[0105] In the formula, It is The photoacoustic signal received by the detector is From the detector To the imaging point The projection factor.

[0106] Projection Factor It can be defined as:

[0107]

[0108] In the formula, is the angle between the detector and the imaging point.

[0109] Step S182: determine the region of interest of the photoacoustic intensity image slice, and calculate the temperature of the region of interest using the absorption intensity-photoacoustic excitation intensity calculation formula to obtain the temperature distribution of the region of interest.

[0110] In the above step S182, those skilled in the art can determine the region of interest of the photoacoustic intensity image slice according to actual application requirements. After determining the region of interest, the temperature of the region of interest can be calculated using the absorption intensity-photoacoustic excitation intensity calculation formula obtained above.

[0111] In the above implementation process, by using the image reconstruction algorithm to determine the photoacoustic intensity image slice and calculating the temperature distribution of the area of ​​interest in the photoacoustic intensity image slice, not only the accuracy and reliability of the measurement results are further improved, but also more intuitive and comprehensive temperature information is provided.

[0112] In some optional implementations, step S180 may further include:

[0113] Step S183: real-time correction of the propagation velocity of the acoustic wave signal generated by the sample during the absorption of the pulse laser based on the measurement of the acoustic wave transmission element.

[0114] In the above step S183, a fixed-length component may be used to calibrate the propagation speed of the acoustic wave signal at multiple temperatures to be measured.

[0115] Accordingly, step S181 may include:

[0116] Step S1811: reconstruct the image of the acoustic wave signal generated when the temperature target absorbs the pulsed laser by using the image reconstruction algorithm and the propagation rate of the acoustic wave signal to obtain a photoacoustic intensity image slice.

[0117] In the above step S1811, in combination with the DAS algorithm and the BP algorithm specifically introduced above, the propagation speed of the acoustic wave signal can be introduced in the process of correcting the size of the image reconstruction to ensure that the influence of temperature changes on the sound speed has been taken into consideration.

[0118] In the above implementation process, the propagation speed of the acoustic wave signal at multiple temperatures that need to be measured is calibrated, and the propagation speed of the acoustic wave signal is introduced in the process of correcting the size of the image reconstruction, thereby further improving the accuracy of the reconstructed image size, thereby further improving the accuracy of the final measured temperature.

[0119] Please refer to Figure 7 , Figure 71 is a schematic diagram of the structure of the temperature measuring device 100 provided in the embodiment of the present application. Based on the same concept, the embodiment of the present application also provides a temperature measuring device 100, which may include a controller 110, an acoustic wave sensor 120, a temperature sensor 130, a laser emitting component 140, a cuvette 150, a temperature control component 160 and a housing 170. An acoustic wave coupling agent 180 isotropic with the sample to be measured may be provided in the housing 170, wherein the isotropy of the acoustic wave coupling agent 180 and the sample to be measured is not absolutely identical, but refers to the close isotropy between the two. Taking the measured object as water as an example, the reference coupling agent material may be: ethylene glycol, dimethyl silicone oil. The cuvette 150 may be located in the housing 170 and may be immersed in the acoustic wave coupling agent 180. The cuvette 150 may be used to hold a sample. Also, taking the measured object as water as an example, the reference cuvette material may be: low-density polyethylene, polystyrene. The laser emitting assembly 140 may be located in the housing 170 and electrically connected to the controller 110. The laser output end of the laser emitting assembly 140 may be directed toward the cuvette 150 and may be used to emit a pulsed laser to the cuvette 150. The acoustic wave sensor 120 may be located in the housing 170 and electrically connected to the controller 110. The acoustic wave collecting end of the acoustic wave sensor 120 may be directed toward the cuvette 150 and may be used to collect acoustic wave signals from the cuvette 150. The temperature sensor 130 may be located in the cuvette 150 and electrically connected to the controller 110. The temperature sensor 130 may be used to collect the temperature of the sample. The temperature control end of the temperature control assembly 160 may be located in the housing 170 and immersed in the acoustic wave coupling agent 180. The temperature control assembly 160 is electrically connected to the controller 110. The controller 110 may be used to execute the various method steps described above.

[0120] The controller 110 may specifically be a computer, the temperature sensor 130 may specifically be a combination of a thermocouple and a temperature data acquisition instrument, and the laser emitting assembly 140 may include a laser 141 and a laser controller 110 .

[0121] The temperature control component 160 can control the acoustic wave coupling agent 180 in the housing 170 based on the temperature set by the computer, thereby controlling the temperature of the cuvette 150 and the sample.

[0122] The thermocouple can detect the temperature of the sample in the cuvette 150 and send the generated temperature signal to the temperature data acquisition instrument, which then sends the temperature signal to the computer, and the computer can record the temperature data at the corresponding time.

[0123] The laser controller 110 can set the power of the pulsed laser based on the computer and control the laser 141 to emit a pulsed laser. The sample generates heat after absorbing the pulsed light, and generates sound waves due to vibration caused by thermal expansion and contraction. The sound wave coupling agent 180 transmits the sound waves, which are received by the sound wave sensor 120 and transmitted to the sound wave signal collector, and then sent to the computer for integration and storage.

[0124] The above implementation process may be the same as the temperature measurement method described above, and will not be described in detail here.

[0125] Please continue to refer to Figure 7 In some optional embodiments, the temperature control component 160 may include a constant temperature medium container 161, a heat conductor 162, and a pipe 163. The constant temperature medium container 161 may contain a constant temperature medium and be electrically connected to the controller 110. The heat conductor 162 may have a flow channel for the constant temperature medium to flow, and may be located in the housing 170 and immersed in the acoustic wave coupling agent 180. The heat conductor 162 may be connected to the constant temperature medium container 161 through the pipe 163. The constant temperature medium container 161 may be configured to adjust the temperature of the constant temperature medium under the control of the controller 110, and allow the constant temperature medium to flow through the flow channel of the heat conductor 162.

[0126] The constant temperature medium container 161 may be a constant temperature circulating water tank, which can control the temperature of the internal constant temperature medium and circulate the constant temperature medium between the constant temperature circulating water tank and the heat conducting member 162. The constant temperature medium may be water, and the heat conducting member 162 may be a spiral coil made of a heat conducting material.

[0127] In the above implementation process, the temperature control component 160 is composed of the constant temperature medium container 161, the heat conductor 162 and the pipe 163. On the basis of achieving the temperature control of the colorimetric dish 150 and the sample, the structure of the temperature control component 160 is simplified.

[0128] Please continue to refer to Figure 7 In some optional embodiments, the laser emitting assembly 140 may include a laser 141 and a combined lens 142. The laser 141 is electrically connected to the controller 110 and may be used to emit pulsed laser light under the control of the controller 110. The combined lens 142 is located on the optical path of the laser emitted by the laser 141 and may be used to shape the laser light emitted by the laser 141 and modulate the wavelength and spot shape.

[0129] The combined lens 142 may be located between the laser 141 and the cuvette 150. Specifically, the combined lens 142 may be an aspheric lens group, a birefringent lens group, or the like.

[0130] In the above implementation process, the pulse laser emitted by the laser 141 is shaped by the combined lens 142 to ensure accurate irradiation of the sample by the pulse laser, thereby further improving the accuracy of temperature measurement.

[0131] For further understanding, please refer to 8. Figure 8 It is a stereoscopic diagram of a temperature measuring device 100 provided in another embodiment of the present application. The temperature measuring device 100 provided in another embodiment of the present application may include: an insulating shell 4, two constant temperature circulating liquid pipeline 3 joints 1, a set of constant temperature circulating liquid pipeline 3, a perforated upper plate 5, a photoacoustic probe 6 fixing device 2, a photoacoustic probe 6, a set of sample fixtures 7 and a sample cuvette 8, wherein the photoacoustic probe 6 is a photoacoustic transceiver composed of a laser generator and a pulsed laser combined lens, which can control the emission of a specified laser on the sample, and at the same time transmit the acoustic wave signal to the acoustic wave signal collector through an acoustic wave coupling agent. The insulating shell 4 can support the upper plate 5 and cooperate with the upper plate 5 to form a liquid container. The container has a connection hole for connecting the pipeline so that the pipeline can be partially extended and fixed in the container, and has a threaded hole that can be connected to the photoacoustic probe 6 fixing device 2 to fix the relative position of the photoacoustic probe 6 and the sample. In addition, the container has a line hole that allows optical fiber, sensor harness, etc. to enter. The photoacoustic probe 6 fixing device 2 connected to the container can cooperate with the photoacoustic probe 6 and the sample fixture 7 through the flange, so that the relative spatial position between the photoacoustic probe 6 and the sample cuvette 8 is fixed to ensure the measurement accuracy.

[0132] Based on the same concept, an embodiment of the present application further provides a storage medium, which includes a computer-readable storage medium. The computer-readable storage medium stores a computer program, and the computer program executes the above method when executed by a processor.

[0133] Since the laser source and wavelength controller, ultrasonic collector, temperature measuring device, and temperature control device need to synchronize time frames and share data across multiple devices when the entire temperature measurement system is working, time synchronization can also be performed when executing the method described above.

[0134] Due to data throughput reasons, it is recommended to use an SSD hard drive of 8T or more or use a pool of multiple solid-state hard drives for storage to ensure data storage and processing needs.

[0135] Due to the limitation of data frame frequency, too low data frame will seriously affect the photoacoustic relaxation phenomenon, and then affect the photoacoustic signal intensity. It is recommended to use more than 64GD of memory, and it is best to use 128GB of memory for average batch processing of data frames.

[0136] Among them, the computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable red-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0137] In several embodiments provided by the present application embodiment, it should be understood that the disclosed method can also be implemented in other ways. Each box in the flow chart or block diagram can represent a part of a program segment or code, and a part of a program segment or code includes one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the flow chart and the combination of the boxes in the block flow chart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0138] The above description is only an optional implementation manner of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the embodiments of the present application, which should be covered within the protection scope of the embodiments of the present application.

Claims

1. A method for measuring temperature, characterized in that: include: The measurement system is used to measure the absorbance of the sample to the pulse laser at different temperatures, and a relationship curve between temperature and absorbance is obtained; The original Grignard coefficient is corrected by using the correction term of Grignard coefficient in the field of photoacoustics, and the calculation formula of absorption intensity-photoacoustic excitation intensity between absorbance and sound wave intensity is obtained; Further, the absorbance-temperature curve at this wavelength is introduced to obtain the sound wave intensity-temperature fitting formula of the target to be measured; as well as The ROI region signal after image reconstruction using the photoacoustic reconstruction algorithm is brought into the acoustic wave intensity-temperature fitting formula to obtain the temperature of the target to be measured.

2. The method according to claim 1, characterized in that: The method comprises measuring the absorbance of the sample to the pulsed laser at different temperatures using the measuring system and obtaining a relationship curve between the temperature and the absorbance, including: Using a spectrophotometer to measure the absorption spectra of the samples at different temperatures; and A relationship curve between temperature and absorbance is determined according to the absorption spectrum.

3. The method according to claim 1, characterized in that: After measuring the absorbance of the sample to the pulsed laser at different temperatures by using the measurement system and obtaining a relationship curve between temperature and absorbance, the method further includes: The absorption singular point in the relationship curve where the sample temperature is insensitive to the change in absorbance is used to correct the error of the test system; wherein the error includes the system error of the laser energy stability and the temperature control device and the gross error of the measurement; the absorption singular point is a point where the maximum absorption difference is less than 0.001abs, and the maximum temperature difference in the temperature range during the correction of the test system does not exceed the temperature difference threshold of the test system.

4. The method according to claim 3, characterized in that The method of using the absorption singular point in the relationship curve to which the sample temperature is insensitive to the change in absorbance to correct the error of the test system includes: Using the absorption singular point to perform absorption intensity range normalization correction; Correct the laser energy stability; Correcting the system errors of the temperature control device; and Correction for gross errors in measurement.

5. The method according to claim 4, characterized in that The original Grignard coefficient is corrected by using the correction term of the Grignard coefficient in the field of photoacoustics to obtain the absorption intensity-photoacoustic excitation intensity calculation formula between absorbance and sound wave intensity, including: The original photoacoustic correction term of thermal saturation caused by absolute temperature change in the photoacoustic field is used to correct the original photoacoustic, and the photoacoustic dynamic formula in the photoacoustic excitation-absolute temperature change correction formula and the dynamic correction term introduced by the absolute temperature change are obtained; among them, The dynamic correction term introduced by the absolute temperature change is: ； The corrected photoacoustic dynamic correction formula is: ； In the formula, is the correction term caused by the absolute temperature change, λ i is the wavelength, μ a is the light absorption coefficient, p0 is the corrected photoacoustic pressure, F pulse is the light flux of a single pulse, b is a constant that at least characterizes the physical properties of the sample material and the measurement system, is the thermal relaxation time constant, is the thermal energy conversion efficiency, is the base Gruenneisen coefficient, is the time interval between pulses of the pulsed laser; The dynamic correction formula, the light source parameters of the pulsed laser, the normalization coefficient obtained from the singular point, the energy correction parameters of the test system, and the temperature control compensation parameters are substituted into the photoacoustic excitation intensity formula to obtain the absorption intensity-photoacoustic excitation intensity calculation formula.

6. The method according to claim 1, characterized in that The ROI region signal after image reconstruction using the photoacoustic reconstruction algorithm is brought into the absorption intensity-photoacoustic excitation intensity calculation formula to obtain the temperature of the target to be measured, including: Reconstructing the image of the acoustic wave signal generated by the target to be measured absorbing the pulse laser by using an image reconstruction algorithm to obtain a photoacoustic intensity image slice of the target to be measured; and The region of interest of the photoacoustic intensity image slice is determined, and the temperature of the region of interest is calculated using the absorption intensity-photoacoustic excitation intensity calculation formula to obtain the temperature distribution of the region of interest.

7. The method according to claim 6, characterized in that The method of measuring the temperature of the target to be measured according to the sound wave intensity of the target to be measured and the absorption intensity-photoacoustic excitation intensity calculation formula also includes: The real-time correction is based on the propagation rate of the acoustic wave signal generated by the sample in the process of absorbing the pulse laser measured by the acoustic wave conductor; The method of reconstructing the acoustic wave signal generated by the target to be measured in the process of absorbing the pulse laser by using an image reconstruction algorithm to obtain a photoacoustic intensity image slice of the target to be measured comprises: The image reconstruction algorithm and the propagation rate of the wave signal are used to reconstruct the image of the acoustic wave signal generated during the process of the target to be measured absorbing the pulse laser, so as to obtain the photoacoustic intensity image slice.

8. A temperature measuring device, characterized in that: It includes a controller, an acoustic wave sensor, a temperature sensor, a laser emission component, a cuvette, a temperature control component and a housing; The shell is provided with an acoustic wave coupling agent which is isotropic with the sample to be tested; The cuvette is located in the housing and is immersed in the acoustic wave coupling agent; the cuvette is used to hold a sample; the cuvette is made of a material that is isotropic, uniform, and highly transparent to the sample being tested; The laser emitting assembly is located in the housing and is electrically connected to the controller; the laser output end of the laser emitting assembly faces the cuvette and is used to emit pulsed laser to the cuvette; The acoustic wave sensor is located in the housing and is electrically connected to the controller; the acoustic wave collecting end of the acoustic wave sensor faces the cuvette and is used to collect the acoustic wave signal from the cuvette; The temperature sensor is located in the cuvette and is electrically connected to the controller; the temperature sensor is used to collect the temperature of the sample; The temperature control end of the temperature control component is located in the housing and immersed in the acoustic wave coupling agent; the temperature control component is electrically connected to the controller; The controller is used to: measure the absorbance of the sample to the pulsed laser at different temperatures by using a measurement system, and obtain a relationship curve between temperature and absorbance; correct the original Grignard coefficient by using the correction term of the Grignard coefficient in the photoacoustic field, and obtain the absorption intensity-photoacoustic excitation intensity calculation formula between the absorbance and the sound wave intensity; further bring in the absorbance versus temperature curve at this wavelength to obtain the sound wave intensity-temperature fitting formula of the temperature target to be measured; And the ROI area signal after image reconstruction using the photoacoustic reconstruction algorithm is brought into the sound wave intensity-temperature fitting formula to obtain the temperature of the target to be measured.

9. The temperature measuring device according to claim 8, characterized in that: The temperature control assembly includes a constant temperature medium container, a heat conducting member and a pipeline; The constant temperature medium container contains a constant temperature medium and is electrically connected to the controller; The heat conducting member has a flow channel for the constant temperature medium to flow, and is located in the housing and immersed in the acoustic wave coupling agent; The heat conducting member is connected to the constant temperature medium container through the pipeline; The constant temperature medium container is configured to adjust the temperature of the constant temperature medium under the control of the controller and allow the constant temperature medium to flow through the flow channel of the heat conducting member.

10. The temperature measuring device according to claim 8, characterized in that: The laser emission assembly includes a laser and a combined lens; The laser is electrically connected to the controller and is used to emit pulsed laser under the control of the controller; The combined lens is located on the optical path of the laser emitted by the laser, and is used to shape the laser emitted by the laser and modulate the wavelength and spot shape.

11. A storage medium, characterized in that: The storage medium comprises a computer-readable storage medium; a computer program is stored on the computer-readable storage medium, and the computer program executes the method according to any one of claims 1 to 7 when executed by a processor.

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