阅读说明：本技术 一种耳腔成像区域多自由度控制的非接触温度测量方法 (Non-contact temperature measurement method for multi-degree-of-freedom control of ear cavity imaging area ) 是由 王自鑫 蔡志岗 赵伟鸿 李文哲 张锡斌 黄柱源 王福娟 王嘉辉 李佼洋 于 2020-05-08 设计创作，主要内容包括：本发明公开了一种耳腔成像区域多自由度控制的非接触温度测量方法,该方法包括以下步骤：耳腔及周边区域的热力学及黑体辐射简化模型建立,推导温度反演算法,仿真计算,实验验证,验证通过后模型复杂程度逐渐增加,重复上述模型验证的过程,逐步建立逼近人耳真实情况的过渡模型和复杂模型；结合双目视觉3d重构技术重构耳朵的三维结构并分区；该方法解决的问题是建立复杂环境下耳腔及周边区域的热力学温度的表面分布和辐射通量的空间分布模型,结合有限元分析方法和实验手段,对模型进行理论和实验的双重验证；该方法具有适应复杂环境,测量精度高,非接触式的特点,可以广泛应用于各种复杂环境下的耳温测温场景。(The invention discloses a non-contact temperature measurement method for multi-degree-of-freedom control of an ear cavity imaging area, which comprises the following steps: establishing a thermodynamic and black body radiation simplified model of an ear cavity and a peripheral area, deducing a temperature inversion algorithm, carrying out simulation calculation and experimental verification, gradually increasing the complexity of the model after verification, repeating the process of model verification, and gradually establishing a transition model and a complex model which approximate to the real condition of the human ear; reconstructing a three-dimensional structure of an ear by combining a binocular vision 3d reconstruction technology and partitioning; the method solves the problem that a spatial distribution model of thermodynamic temperature surface distribution and radiation flux of an ear cavity and a peripheral area in a complex environment is established, and double verification of theory and experiment is carried out on the model by combining a finite element analysis method and an experimental means; the method has the characteristics of adaptation to complex environments, high measurement precision and non-contact, and can be widely applied to ear temperature measurement scenes in various complex environments.)

1. A non-contact temperature measurement method for multi-degree-of-freedom control of an ear cavity imaging area is characterized by comprising the following steps of: the method comprises the following steps of establishing a thermodynamic and black body radiation simplified model of an ear cavity and a peripheral area, deducing a temperature inversion algorithm, carrying out simulation calculation and experimental verification, gradually increasing the complexity of the model after verification, repeating the process of model verification, and gradually establishing a transition model and a complex model which are close to the real situation of human ears.

2. The method of claim 1, wherein the simplified modeling comprises simplifying a three-dimensional complex biological structure into a two-dimensional disc-shaped geometry, wherein the ear cavity is a small circle, the ear cavity peripheral area is a large circle, the temperature of the ear cavity is T1, and the ear cavity peripheral temperature partition is T2, T3.

3. The method as claimed in claim 1, wherein the simplified model building comprises deriving a formula for radiation field distribution in the ear cavity and its surrounding areas, the formula is used for model building, and there are theoretical formulas corresponding to the models for numerical simulation calculation from the simplified model to the complex model and the intermediate transition model.

4. The method of claim 1, wherein for the finally established model, the binocular vision 3d reconstruction technique is combined to reconstruct the three-dimensional structure of the ear and partition the ear, and the information is brought into the model to serve as the modeling parameters of the model.

5. The method for non-contact temperature measurement with multi-degree-of-freedom control of an ear cavity imaging region according to claim 4, wherein the binocular vision 3d reconstruction technique comprises reconstructing the geometric structure of the ear cavity and the peripheral region thereof, so as to obtain the three-dimensional coordinates of the region, including the information of the curved surface shape and the radiation angle of the tangent plane; and substituting the part of the geometric structure information of the human ear into the established model formula for measuring the temperature of the human ear cavity under the real condition.

6. The method for measuring the non-contact temperature of the ear cavity imaging area under the multi-degree-of-freedom control according to claim 5, is characterized in that a plurality of groups of different samples are selected for temperature measurement in different experimental environments, and compared with a traditional contact type temperature measurement mode, the accuracy of the model in a standard test environment and a complex environment is verified, so that the model is comprehensively verified and evaluated, and the model is further modified and perfected according to experimental results so as to improve the applicability and the robustness of the model in different scenes.

7. The method of claim 1, wherein the derived temperature inversion algorithm comprises using the probe to collect different information about the ear cavity and its surrounding area with multiple degrees of freedom, and combining the geometric model of the ear cavity and the temperature partition, the algorithm realizes extracting the temperature information about different partitions of the ear from the complex information collected with these different degrees of freedom.

8. The method as claimed in claim 1, wherein the core method for implementing the algorithm in the derived temperature inversion algorithm is to perform multi-degree-of-freedom measurement on the imaging region, the multi-degree-of-freedom measurement means includes probe translation, rotation, and tilt operations, and during this process, the probe collects different information of the ear cavity and its surrounding regions from multiple angles.

9. The method of claim 8, wherein the derivation of the temperature inversion algorithm comprises the following steps: a lens is arranged in front of a thermopile probe for measuring radiation flux, radiation on the surface of a black body can be converged on the thermopile probe through the lens, the thermopile probe converts the radiation flux into a voltage signal, the focusing formula and the magnification formula of the lens can know that the total radiation flux received by the thermopile probe is the integral sum of all radiation microelements in an imaging area of the surface of the black body, and a theoretical formula of the radiation flux and a plurality of groups of different parameter combinations can be derived from theory; firstly, calibrating the radiation flux-output voltage of the probe by using a standard black body, then enabling the center of the probe to face an ear cavity model, changing the imaging position, the imaging area and the imaging angle of an imaging area from multiple degrees of freedom by using the methods of moving, inclining, adjusting the focal length and moving back and forth of the probe, collecting enough temperature information of the ear cavity and the peripheral area in the process, collecting the information in a mode of converting radiation integral into voltage, comparing whether a derived theoretical formula is consistent with a voltage signal collected by the probe or not, and if the consistency is good, indicating that the model is correctly established, and verifying the model to be passed.

10. The method for measuring the non-contact temperature of the ear cavity imaging region with multiple degrees of freedom control according to claim 1, wherein the gradual increase of the complexity of the model is to further add elements which meet practical conditions on the basis of simplifying the model, the elements comprise an ear edge region temperature partition, a two-dimensional plane model which is converted into a three-dimensional model, and elements which add the ambient temperature and the ambient radiation, and the complete modeling thought is as follows: the method comprises the steps of firstly carrying out simplified model verification, carrying out temperature partition on an ear area after the simplified model verification is passed, then converting a two-dimensional plane structure into a three-dimensional stereo structure, finally adding elements of environmental temperature and environmental radiation, deducing a new formula when the model is further complicated every time, and then carrying out numerical simulation calculation and experimental verification.

Technical Field

The invention relates to the technical field of temperature measurement, in particular to a non-contact temperature measurement method for multi-degree-of-freedom control of an ear cavity imaging area.

Background

The working principle of infrared thermal imaging is that an infrared detector is utilized to receive the infrared radiation energy distribution of a detected target and reflect the infrared radiation energy distribution to a photosensitive element of the infrared detector, so that an infrared thermal image is obtained. This thermographic image corresponds to the temperature distribution of the surface of the object. Through the infrared thermograph, the overall temperature distribution condition of the measured object can be observed, and the heating condition of the measured object can be researched. Research shows that under the conditions of different ages, different room temperatures and different body temperatures, the difference between the oral cavity temperature and the ear temperature has no statistical significance, the consistency degree between the ear temperature and the oral cavity temperature is high, and the ear temperature obtained by infrared measurement can accurately and truly reflect the body temperature condition clinically.

At present, the infrared thermal imaging technology for human body temperature measurement in the aspects of security inspection and the like mainly uses devices such as a body temperature gun, a temperature measurement door and the like, and cannot measure the temperature of the ear cavity of a human body. The domestic ear thermometer has the defects of contact and low temperature measurement precision. In order to meet the requirements of medical science and quarantine development in China, effectively measure body temperature and powerfully control and prevent the spread of special diseases such as influenza A, SARS and the like, a non-contact ear temperature measuring method which is suitable for complex environment, has high measuring precision is urgently needed to be designed. By constructing an ear cavity model, measuring an imaging region by multi-degree-of-freedom control on the basis of the model to obtain multi-dimensional information and inverting the method for temperature partition in the ear cavity and the surrounding region, the ear temperature can be measured with high precision in a non-contact manner, and the method has very important significance.

Disclosure of Invention

The invention aims to provide a high-precision human body infrared temperature measurement method which has the basic principle that black body radiation is adopted, the heat radiation quantity emitted by objects with different temperatures is different, and an infrared probe is utilized to collect the heat radiation emitted by the objects and convert the heat radiation into an electric signal. In order to solve the problem of inaccurate temperature measurement of a measured object caused by radiation influence of objects around the measured object, a model with a simplified ear cavity is provided, and a method for measuring and obtaining multi-dimensional information and inverting the temperature zones in the ear cavity and the surrounding area by carrying out multi-degree-of-freedom control on an imaging area on the basis of the model is provided. On the basis, the model is gradually complicated, and a complex model conforming to an actual application scene is gradually constructed. The method can improve the precision, and can deduce the temperature partition information of the peripheral area of the measured object according to the model to obtain more information.

In order to solve the problems, the invention provides a non-contact temperature measurement method for multi-degree-of-freedom control of an ear cavity imaging region, which comprises the following steps: the method comprises the following steps of establishing a thermodynamic and black body radiation simplified model of an ear cavity and a peripheral area, deducing a temperature inversion algorithm, carrying out simulation calculation and experimental verification, gradually increasing the complexity of the model after verification, repeating the process of model verification, and gradually establishing a transition model and a complex model which are close to the real situation of human ears.

In a further improvement, the simplified modeling comprises simplifying the three-dimensional complex biological structure into a two-dimensional disc-shaped geometry, wherein the ear cavity is a small circle, the peripheral region of the ear cavity is a large circle, the temperature of the ear cavity is T1, and the temperature zone around the ear cavity is T2, T3.

The further improvement is that the simplified model establishment comprises the derivation of a formula for the radiation field distribution of the ear cavity and the peripheral region thereof, the formula is used for model establishment, and theoretical formulas corresponding to the models are used for numerical simulation calculation from the simplified model to the complex model and the intermediate transition model.

The further improvement is that for the finally established model, the three-dimensional structure of the ear is reconstructed and partitioned by combining the binocular vision 3d reconstruction technology, and the information is brought into the model to be used as the modeling parameters of the model.

The further improvement is that the binocular vision 3d reconstruction technology comprises the steps of reconstructing the geometric structures of the ear cavity and the peripheral area thereof, so as to obtain the three-dimensional coordinates of the area, including the information of the curved surface shape and the radiation angle of the tangent plane; and substituting the part of the geometric structure information of the human ear into the established model formula for measuring the temperature of the human ear cavity under the real condition.

The method is further improved in that a plurality of groups of different samples are selected to measure temperature in different experimental environments, the temperature is compared with a traditional contact type temperature measurement mode, the accuracy of the model in a standard test environment and a complex environment is verified, the model is comprehensively verified and evaluated, the model is further modified and perfected according to experimental results, and the applicability and the robustness of the model in different scenes are improved.

In a further improvement, the derivation temperature inversion algorithm comprises the steps of collecting different information of the ear cavity and the peripheral area thereof from multiple degrees of freedom by using the probe, and combining a geometric model of the ear cavity and temperature partitions, wherein the algorithm realizes that the temperature information of different partitions of the ear is extracted from the complex information collected under the different degrees of freedom.

The further improvement is that the core method for realizing the algorithm in the derivation temperature inversion algorithm is to carry out multi-degree-of-freedom measurement on an imaging region, the multi-degree-of-freedom measurement means comprises the operations of translation, rotation and inclination of the probe, and in the process, the probe collects different information of the ear cavity and the peripheral region thereof from multiple angles.

The further improvement is that the specific process of deriving the temperature inversion algorithm is as follows: a lens is arranged in front of a thermopile probe for measuring radiation flux, radiation on the surface of a black body can be converged on the thermopile probe through the lens, the thermopile probe converts the radiation flux into a voltage signal, the focusing formula and the magnification formula of the lens can know that the total radiation flux received by the thermopile probe is the integral sum of all radiation microelements in an imaging area of the surface of the black body, and a theoretical formula of the radiation flux and a plurality of groups of different parameter combinations can be derived from theory; firstly, calibrating the radiation flux-output voltage of the probe by using a standard black body, then enabling the center of the probe to face an ear cavity model, changing the imaging position, the imaging area and the imaging angle of an imaging area from multiple degrees of freedom by using the methods of moving, inclining, adjusting the focal length and moving back and forth of the probe, collecting enough temperature information of the ear cavity and the peripheral area in the process, collecting the information in a mode of converting radiation integral into voltage, comparing whether a derived theoretical formula is consistent with a voltage signal collected by the probe or not, and if the consistency is good, indicating that the model is correctly established, and verifying the model to be passed.

The further improvement lies in that the model complexity gradually increases is that the elements meeting the actual conditions are further added on the basis of simplifying the model, including the elements that ear area temperature partition, two-dimensional plane model are converted into three-dimensional solid model, and the elements that add ambient temperature and ambient radiation, and the complete modeling thought is: the method comprises the steps of firstly carrying out simplified model verification, carrying out temperature partition on an ear area after the simplified model verification is passed, then converting a two-dimensional plane structure into a three-dimensional stereo structure, finally adding elements of environmental temperature and environmental radiation, deducing a new formula when the model is further complicated every time, and then carrying out numerical simulation calculation and experimental verification.

The invention has the beneficial effects that: the invention not only collects the information of the measured object, but also collects the information of the peripheral objects of the measured object, thereby not only obtaining the temperature of the measured object, but also obtaining the temperature of the area around the measured object. In addition, the method can also distinguish the contribution of the temperature of the measured object and the temperature of the peripheral object to the probe signal, thereby avoiding the interference of the peripheral radiation of the measured object and improving the accuracy of temperature measurement. The method has the characteristics of adaptation to complex environments, high measurement precision and non-contact, and can be widely applied to ear temperature measurement scenes in various complex environments.

Drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is a simplified ear cavity and temperature zone model schematic of the present invention;

FIG. 3 is a calibration graph of thermopile probe radiation flux versus output voltage in accordance with the present invention;

FIG. 4 is a schematic view of the geometric relationship between the imaging area of the lens and a simplified model of the ear cavity of the present invention;

FIG. 5 is a curved view of the variation of the radiation flux in the imaging area during scanning according to the present invention;

FIG. 6 is a general model diagram of the imaging system of the present invention.

Detailed Description

While the present application will be described in further detail with reference to the accompanying figures 1-6, it is to be noted that the following detailed description is provided for purposes of illustration only and is not to be construed as a limitation on the scope of the present application, as numerous insubstantial modifications and adaptations of the present application may be made by those skilled in the art based on the teachings set forth herein.

As shown in fig. 1, a non-contact temperature measurement method for ear cavity imaging region with multiple degrees of freedom control comprises the following steps: the method comprises the following steps of establishing a thermodynamic and black body radiation simplified model of an ear cavity and a peripheral area, deducing a temperature inversion algorithm, carrying out simulation calculation and experimental verification, gradually increasing the complexity of the model after verification, repeating the process of model verification, and gradually establishing a transition model and a complex model which are close to the real situation of human ears.

The process of the present invention is specifically illustrated below: in the thermodynamic and black body radiation simplified model building of the ear cavity and the peripheral area, because the actual human ear model is a biological model, the thermodynamic temperature distribution condition of the surface and the inside of the human ear and the complexity thereof are very difficult, the direct modeling of the real human ear is a very difficult matter, and the built model is difficult to conform to the actual condition, so the problem of simplification at the initial stage of research is needed, the model is properly corrected by combining the actual condition after the simple model verification is passed, the complexity is gradually increased, and the model gradually approaches the real condition of the human ear.

Fig. 2 shows a simplified human ear model, which simplifies the three-dimensional complex shape of the ear cavity into a two-dimensional planar structure, and simplifies the inside and outside of the ear cavity into a disc model, wherein the inside of the ear cavity is replaced by a black body, the outside of the ear cavity is made of a material close to the skin, the two materials are both kept at a stable and uniform temperature by using a PID temperature control technology, and the temperatures of the two materials are respectively kept at T1 and T2 to simulate the inside and outside temperature environments of the ear cavity.

The method comprises the steps of researching multi-degree-of-freedom imaging multi-dimensional information acquisition and a temperature inversion algorithm of a measured target and a peripheral area, placing a lens in front of a thermopile probe for measuring radiation flux, converging the radiation on the surface of a black body onto the thermopile probe through the lens, converting the radiation flux into a voltage signal by the thermopile probe, knowing that the total radiation flux received by the thermopile probe is the integral sum of all radiation microelements in the imaging area of the surface of the black body according to a focusing formula and a magnification formula of the lens, and deducing a theoretical formula of combination of the radiation flux and a plurality of groups of different parameters from the theory;

as shown in fig. 3, firstly, the calibration of the radiation flux-output voltage of the probe is carried out by using a standard black body, then the center of the probe is directly opposite to an ear cavity model, the imaging position, the imaging area and the imaging angle of an imaging area are changed from a plurality of degrees of freedom by using the methods of moving, inclining, adjusting the focal length, moving back and forth and the like of the probe, as shown in fig. 4, a geometrical relationship schematic diagram of the imaging area of the lens and a simplified model of the ear cavity is shown, enough temperature information of the peripheral area of the ear cavity is collected in the process, the information is collected in a mode of converting radiation integral into voltage, whether a derived theoretical formula is consistent with a voltage signal collected by the probe or not is compared, if the consistency is good, the model is correctly established; FIG. 5 is a graph showing a curved surface of the variation of the radiant flux of an imaging area during scanning according to the present invention;

after the model verification passes, the algorithm is used for actual measurement for further verification, a set of known parameters (T1, T2 … and Tn) is set for the model, a voltage curve acquired in the process of changing the multiple degrees of freedom and different curves under multiple groups of different parameters in a theoretical model are respectively subjected to correlation operation, a group of parameters with the highest correlation degree is taken as a measured value, whether errors of the measured value (T1 ', T2 ' … and Tn ') and the preset value (T1, T2 … and Tn) meet the precision requirement or not is compared, if so, the correctness of the model is further verified, and if not, the model is further modified until the precision requirement is met.

The thermodynamic distribution and the radiant flux distribution mechanism of the ear cavity and the peripheral area are revealed, the model is gradually complicated, a complex model conforming to the practical application scene is constructed, a plurality of elements conforming to the practical situation are further added on the basis of the simplified human ear model, the elements comprise the elements of ear area temperature partition, two-dimensional plane model conversion into a three-dimensional model, and addition of environment temperature and environment radiation, and the complete modeling idea is as follows: the method comprises the steps of firstly carrying out simplified model verification, carrying out temperature partition on an ear area after the simplified model verification is passed, then converting a two-dimensional plane structure into a three-dimensional stereo structure, finally adding elements of environmental temperature and environmental radiation, deducing a new formula when the model is further complicated every time, and then carrying out numerical simulation calculation and experimental verification.

And (3) establishing a three-dimensional geometric model of a real human ear by combining the existing binocular vision 3d reconstruction technology or other technologies, and carrying out actual measurement verification on the complex model of the human ear thermodynamics and radiant flux distribution. The establishment of the human ear thermodynamics and radiant flux distribution model requires obtaining the surface geometric structure information of human ears, the invention adopts the existing three-dimensional model reconstruction technology based on binocular vision, reconstructing the geometric structure of the human ear cavity and the peripheral area thereof to obtain the three-dimensional coordinates of the area, mainly comprising the information of the curved surface shape and the radiation angle of the tangent plane, substituting the information of the geometric structure of the human ear into the established model formula, can be used for measuring the temperature of the ear cavity of the human ear under the real condition, selects a plurality of groups of different samples to measure the temperature under different experimental environments, compared with the traditional contact temperature measurement mode, the model accuracy under the standard test environment and the complex environment is detected, so that the model is comprehensively verified and evaluated, and further modifying and perfecting the model according to the experimental result so as to improve the applicability and robustness of the model in different scenes.

The principle of the invention is as follows: the Planck's law of radiation gives the specific spectral distribution of blackbody radiation, and at a certain temperature, the energy radiated by a blackbody in unit area in unit time, unit solid angle and unit wavelength interval is the formula of the relationship between the spectral radiation exitance M (lambda, T) of the blackbody and the wavelength and thermodynamic temperature:

wherein c is₁＝2πhc²,c₂＝hc/k。

As can be seen from the black body radiation formula, the radiation degree (radiant energy flow) of the black body in the solid angle range (hemisphere) of the solid angle range (0, 2 pi) is independent of the black body angle direction, and the radiation energy flows of the black body in all directions can be considered to be equal. The electric field intensity distribution of a black body per unit area in a unit wavelength interval at a certain temperature is as follows:where (λ) is the emissivity at different wavelengths, for an ideal blackbody, (λ) ═ 1.

The lens image is regarded as a diffraction-limited linear system, the object-image relations of the diffraction-limited system are connected together by a point spread function, and the field distribution U of the object plane is determined₀(x_o,y_o) And the point spread function h (x)_i,y_i；x_o,y₀) Can calculate the field distribution U of the image space focal plane_i(x_i,y_i)。

From the knowledge of fourier optics, the point spread function of a diffraction limited system:

wherein P (x)₁,y₁) As a function of the pupil of the lens.

Field intensity distribution at the image focal plane after a point of the object focal plane passes through the point spread function of the lens image:

wherein f is_o(x_o,y_o)＝1,x_o ²+y_o ²＜s_o ²Is the effective object space focal plane area.

Considering that each surface source of the black body radiation is an incoherent radiation source, the total light intensity received by the detector area is the integral sum of the light intensities contributed by each black body infinitesimal element:

I_i(x_i,y_i；λ)＝{|h(x_i,y_i；x_o,y_o；λ)|²*E_o(x_o,y_o；λ)}·f_i(x_i,y_i)

wherein f is_o(x_i,y_i)＝1,x_i ²+y_i ²＜s_i ²Is the effective image focal plane area.

Total radiation flux received by the detector:

where alpha is the radiation flux weighting factor received by different regions of the detector.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.