High-temperature combustion product infrared area characteristic evaluation method based on large dynamic temperature field distribution characteristics

Abstract

The invention discloses a high-temperature combustion product infrared area characteristic evaluation method based on large dynamic temperature field distribution characteristics. Based on the large dynamic temperature field distribution characteristics of the high-temperature combustion products in the air, the Planck law is introduced into the infrared area characteristic evaluation of the high-temperature combustion products, the edge temperature threshold T0 of an equivalent black body temperature field is set, the corresponding edge gray threshold G0 of a target area is obtained through conversion, and then the target area extraction algorithm processing is carried out, so that the infrared area characteristic evaluation of the high-temperature combustion products is realized. An image pixel area with the equivalent black body temperature higher than T0 in the temperature field and the pixel number N are extracted, and then the infrared area S of a high-temperature combustion product target area with the equivalent black body temperature higher than T0 can be calculated according to observation parameters. The method is clear in physical significance, an air gas area heated by the high-temperature combustion product can be effectively stripped, a target area of the high-temperature combustion product in a specified temperature range can be extracted according to a test scheme, and infrared area characteristic measurement errors of the high-temperature combustion product caused by mismatching of observation gears can be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of infrared characteristic measurement, and in particular relates to a method for evaluating infrared area characteristics of high-temperature combustion products based on the characteristics of large dynamic temperature field distribution. Background Art

[0002] The measurement and evaluation of infrared equipment indicators is an important part of the development and assessment of infrared equipment. It is related to the working performance of infrared equipment and is also an important basis for the demonstration of infrared equipment iterative upgrade indicators. High-temperature combustion products are an important part of infrared equipment and have the characteristics of large dynamic temperature field distribution. The evaluation of its infrared area characteristics is an important part of the measurement and evaluation of related infrared equipment indicators.

[0003] No literature has been found to elaborate on the method of evaluating the area characteristics of high-temperature combustion products: Li Yong et al., when conducting research on the test of the radiation characteristics of high-temperature combustion products of surface source infrared equipment, only mentioned "selecting the target radiation area through the infrared thermal imager analysis and processing software" to obtain the number of pixels N in the high-temperature combustion product area on the infrared image plane, and then converting it into the target area according to parameters such as the test distance and the test field of view; Li Xin et al. (CN 118761211 A) calculated the area index of high-temperature combustion products of infrared equipment directly based on the total number of high-temperature combustion product pixels N. Relevant scholars did not elaborate on how to extract the high-temperature combustion product pixel area in the infrared image.

[0004] The results of the investigation of existing literature and patents show that most of the existing technologies directly process the surface target extraction algorithm based on the infrared image obtained by the infrared measurement equipment, and then obtain the total number of high-temperature combustion product pixel points N. However, in fact, the high-temperature particles formed when the high-temperature combustion products burn in the air have the characteristics of a large dynamic temperature range temperature field distribution: Li Yong et al. tested that the highest temperature in the center is between 600K and 1500K, and the temperature drops rapidly from the central high temperature point to the surrounding areas, and the air gas is heated at the outer edge until it is close to the ambient temperature. On the one hand, it is difficult for a single observation gear of the infrared measurement equipment to meet the measurement requirements of such a large instantaneous dynamic range, and the measurement capability of a single observation gear generally only covers the temperature range of 100K to 200K. This will bring about a problem: if the observation gear selection does not match, such as selecting the high-temperature interval observation gear, the infrared image obtained by the infrared measurement equipment under this observation gear is used for surface target extraction, and only the total number of high-temperature combustion product pixel points N in the high-temperature interval can be obtained, while the pixels in the lower temperature interval will be misjudged as the background area because the grayscale is greatly attenuated to a grayscale close to the ambient temperature, thereby introducing a large measurement error of the area characteristics of the high-temperature combustion products. On the other hand, based on the characteristics of temperature field distribution, the peripheral temperature of high-temperature combustion products slowly decreases and also heats the air gas. Therefore, it is difficult to define the edge of the target area with clear physical meaning based on the image surface target extraction algorithm directly. Therefore, the extracted target area of ​​high-temperature combustion products has no clear physical meaning.

[0005] It can be seen that the infrared area characteristic evaluation of high-temperature combustion products with large dynamic temperature range temperature field distribution characteristics faces many challenges: for example, the single observation gear measurement capability of infrared measurement equipment is difficult to cover the large dynamic temperature range of high-temperature combustion products, and it is easy to introduce large area measurement errors due to mismatch of observation gears, and the extracted target area of ​​high-temperature combustion products does not have a clear physical meaning. In order to solve the above problems, it is urgent to study a method for evaluating the infrared area characteristics of high-temperature combustion products based on the characteristics of large dynamic temperature field distribution to meet the needs of infrared equipment index evaluation. Summary of the invention

[0006] The present invention discloses a method for evaluating the infrared area characteristics of high-temperature combustion products based on the characteristics of large dynamic temperature field distribution, which solves the technical problems existing in the above-mentioned prior art. The method has clear physical meaning, can effectively strip off the air gas area heated by the high-temperature combustion products, can also extract the target area of ​​the high-temperature combustion products within the specified temperature range according to the test plan, and can avoid the measurement error of the infrared area characteristics of the high-temperature combustion products introduced due to the mismatch of the observation gear.

[0007] The present invention provides the following technical solutions:

[0008] The infrared area characteristics evaluation method of high-temperature combustion products based on the large dynamic temperature field distribution characteristics of high-temperature combustion products in the air is based on the large dynamic temperature field distribution characteristics of high-temperature combustion products in the air. The Planck's law is introduced into the infrared area characteristics evaluation of high-temperature combustion products. By setting the edge temperature threshold T of the equivalent blackbody temperature field 0 , convert the corresponding target area edge gray threshold G 0 Then, the target area extraction algorithm is used to extract the equivalent black body temperature in the temperature field higher than the edge temperature threshold T 0 The image pixel area and pixel number N can then be calculated based on the observed parameters to determine the equivalent black body temperature higher than the edge temperature threshold T 0 The infrared area S of the target area of ​​high-temperature combustion products.

[0009] Furthermore, the specific steps of the present invention are as follows:

[0010] (1) Perform system calibration on the infrared measurement equipment used for the area characteristics evaluation of high-temperature combustion products, obtain system calibration parameters, and combine the calibration experimental data to sort out the ideal temperature measurement range of the infrared measurement equipment under different integration times and different transmittance attenuation sheet positions;

[0011] (2) Select the observation distance and field of view according to the measurement requirements of the high-temperature combustion product area characteristics to be evaluated and the parameters of the infrared measurement equipment;

[0012] (3) According to the measurement requirements of the test plan, set the edge temperature threshold T of the equivalent blackbody temperature field of the high-temperature combustion product 0 (K);

[0013] (4) According to the ideal temperature measurement range of the infrared measurement equipment under different integration times and different transmittance attenuation plate positions summarized in (1), select the ideal temperature measurement range covering the edge temperature threshold T 0 (K) The infrared measurement equipment observation gear, that is, the integration time, the attenuation film transmittance gear, and the infrared measurement equipment is configured to measure the equivalent black body temperature of the high-temperature combustion product greater than the edge temperature threshold T 0 (K) area;

[0014] (5) Using the infrared measuring equipment after the gear configuration to observe the high-temperature combustion products and obtain the infrared image of the high-temperature combustion products;

[0015] (6) Based on Planck's law and system calibration results, the blackbody temperature is calculated as the edge temperature threshold T 0 The corresponding high-temperature combustion product target area edge grayscale threshold G 0 ;

[0016] (7) Based on the image edge grayscale threshold G 0Perform target area extraction algorithm processing to extract the equivalent black body temperature in the temperature field that is higher than the edge temperature threshold T 0 The pixel area is obtained by obtaining the equivalent black body temperature higher than the edge temperature threshold T 0 The total number of pixels N in the target area of ​​high-temperature combustion products;

[0017] (8) Combine the observation parameters and observation distance of the infrared measurement equipment to calculate the instantaneous field of view coverage area S of the infrared measurement equipment at the target. IFOV ;

[0018] S IFOV =S FOV / (m×n)=(2tand(α / 2)R) 2 / (m×n) (Formula 8)

[0019] Where m×n represents the specifications of the infrared measurement equipment detector; S FOV is the field of view coverage of the external measurement equipment, m 2 ; α is the field of view of the infrared measurement equipment; R is the observation distance, m;

[0020] (9) Calculate the equivalent blackbody temperature of the high-temperature combustion products to be higher than the edge temperature threshold T 0 Infrared area S:

[0021] S=N×S IFOV (Formula 9).

[0022] Furthermore, the specific steps of step (2) are as follows:

[0023] (2.1) Determine the infrared area characteristic measurement requirements of the high-temperature combustion products to be evaluated, such as the infrared area S must meet the index: ≥ area value S T (m 2 ), where S T Indicates the lower limit of the area required by the indicator;

[0024] (2.2) Reasonably select the field of view angle α (°) and observation distance R (m) of the infrared measurement equipment to ensure that the field of view coverage range S of the infrared measurement equipment FOV (m 2 ) satisfies γ·S FOV ≤S T ≤S FOV :

[0025] S FOV = (2R×tand(α / 2)) 2 (Formula 1)

[0026] γ·S FOV ≤S T ≤S FOV(Formula 2)

[0027] So we have:

[0028]

[0029] Where α is the field of view of the infrared measuring device. If it is a zoom system, the field of view is selected from the calibrated field of view of the device. If it is a fixed-focus system, it is a fixed field of view of the system. γ is the proportional coefficient of the area value of the high-temperature combustion product index occupying the image plane, and takes values ​​in the range of [1 / 2, 4 / 5]. tand is the tangent function. The observation gear refers to the observation field of view, integration time and attenuation plate gear of the infrared measuring device.

[0030] Furthermore, the specific steps of step (6) are as follows:

[0031] (6.1) Based on Planck's law, the calculated temperature is the edge temperature threshold T 0 The infrared radiation brightness L of a black body in the working band; Planck's law can be expressed as:

[0032]

[0033] Where M λ is the blackbody spectral radiation emittance, W·cm -2 ·μm; λ is the wavelength, μm; h is Planck's constant, 6.6256×10 -23 μm·s 2 ; T is the black body temperature, K, take the edge temperature threshold T 0 , that is, T = T 0 ; c is the speed of light, 2.997925×10 10 cm·s -1 ; k is the Boltzmann constant, 1.38054×10 -10 W.s -1 ·K -1 ;

[0034] The temperature is the edge temperature threshold T 0 The black body in the working band [λ 1 ,λ 2 ]The infrared radiation brightness L can be calculated according to the following formula:

[0035]

[0036] (6.2) Based on the system parameters (K, B) of the observation position and the atmospheric transmittance τ under the observation conditions, the blackbody temperature is calculated as the edge temperature threshold T 0 The corresponding high-temperature combustion product target area edge grayscale threshold G 0 :

[0037] G0 =τKL+B (Formula 6);

[0038] (6.3) Statistical target combustion background maximum value G background And the time fluctuation value ΔG, to check and correct the edge gray threshold:

[0039]

[0040] Furthermore, the edge temperature threshold T of the equivalent blackbody temperature field of high-temperature combustion products is 0 The setting basis is the measurement requirements of the test plan, including the assignment method based on ambient temperature and the assignment method based on the target infrared radiation intensity constraint.

[0041] Furthermore, based on the image edge grayscale threshold G 0 When performing the target area extraction algorithm processing, it includes gate tracking and threshold segmentation image processing algorithms based on the miss amount.

[0042] The beneficial effect of the present invention is that it provides a method for evaluating the infrared area characteristics of high-temperature combustion products based on the characteristics of large dynamic temperature field distribution. The evaluation method has clear physical meaning, can effectively strip off the air gas area heated by the high-temperature combustion products, and can also extract the high-temperature combustion product target area within a specified temperature range according to the test plan, and can avoid the introduction of high-temperature combustion product infrared area characteristic measurement errors due to observation gear mismatch. It is a more effective method for evaluating the infrared area of ​​high-temperature combustion products. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of the target area characteristic evaluation method based on the large dynamic temperature field distribution characteristics of the present invention.

[0044] Figure 2 This is a local comparison diagram of the observation and target area extraction of the same type of high-temperature combustion products at different observation gears of the infrared measurement equipment, which can intuitively show the problem of large measurement errors of the infrared area characteristics of high-temperature combustion products due to the mismatch of the observation gear. The left figure is the result of using a low-transmittance attenuation film. The target is distributed in multiple isolated blocks in the infrared image; the right figure is the result of using a high-transmittance attenuation film. The target is distributed in a whole block in the infrared image, and there are only local isolated blocks at the edge. In the left figure, the target's lower temperature area exceeds the lower limit of the ideal dynamic range of the observation gear, and the grayscale of the corresponding area is greatly attenuated to a grayscale close to the ambient temperature, which will be misjudged as the background area. Therefore, under this observation gear, the extracted target area only corresponds to the target high-temperature interval area, and the area evaluation error is large. The target extraction grayscale threshold corresponds to an equivalent blackbody temperature of 443K. In the right figure, the target extraction grayscale threshold corresponds to an equivalent blackbody temperature of 313K, and the extracted target area includes the target's lower temperature interval area.

[0045] Figure 3 In order to set the edge temperature threshold of the equivalent blackbody temperature field of different high-temperature combustion products, a local comparison diagram of the target area extraction of the same high-temperature combustion product infrared observation image can intuitively show the difference in target edge area extraction based on the target temperature field distribution characteristics and the different definition bases of the target edge under the air heating effect. The left figure is the result of the target area extraction using a lower edge temperature threshold, and it can be seen that the relatively low temperature range at the edge is also extracted as a target; the right figure is the result of the target area extraction using a higher edge temperature threshold. The two have different definitions of the lower temperature area and air heating area outside the high-temperature combustion product, and the extracted target area will also be different. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention is further described in detail below with reference to the accompanying drawings:

[0047] The present invention discloses a method for evaluating the infrared area characteristics of high-temperature combustion products based on the large dynamic temperature field distribution characteristics. Based on the large dynamic temperature field distribution characteristics of high-temperature combustion products in the air, the invention introduces Planck's law into the infrared area characteristics evaluation of high-temperature combustion products, and sets the edge temperature threshold T of the equivalent blackbody temperature field. 0 , convert the corresponding target area edge gray threshold G 0 Then, the target area extraction algorithm is used to extract the equivalent black body temperature in the temperature field higher than the edge temperature threshold T 0 The image pixel area and pixel number N can then be calculated based on the observed parameters to determine the equivalent black body temperature higher than the edge temperature threshold T 0 The infrared area S of the high-temperature combustion product target area. This method has clear physical meaning, which can not only effectively strip off the air gas area heated by the high-temperature combustion products, but also extract the high-temperature combustion product target area within the specified temperature range according to the test plan, and avoid the measurement error of the infrared area characteristics of the high-temperature combustion products due to the mismatch of the observation gear.

[0048] Figure 1 The flowchart of the target area characteristic evaluation method based on the large dynamic temperature field distribution characteristics of the present invention is shown. Referring to the flowchart, the specific implementation process of the present invention can be roughly divided into the following nine steps:

[0049] (1) Perform system calibration on the infrared measurement equipment used for the area characteristics evaluation of high-temperature combustion products, obtain system calibration parameters, and combine the calibration experimental data to sort out the ideal temperature measurement range of the infrared measurement equipment under different integration times and different transmittance attenuation sheet positions;

[0050] (2) According to the measurement requirements of the high-temperature combustion product area characteristics to be evaluated and the parameters of the infrared measurement equipment, select the observation distance and observation field angle. The specific steps and methods are as follows:

[0051] (2.1) Determine the infrared area characteristic measurement requirements of the high-temperature combustion products to be evaluated, such as the infrared area S must meet the index: ≥ area value S T (m 2 ), where S T Indicates the lower limit of the area required by the indicator.

[0052] (2.2) Reasonably select the field of view angle α (°) and observation distance R (m) of the infrared measurement equipment to ensure that the field of view coverage range S of the infrared measurement equipment FOV (m 2 ) satisfies γ·S FOV ≤S T ≤S FOV :

[0053] S FOV = (2R×tand(α / 2)) 2 (Formula 1)

[0054] γ·S FOV ≤S T ≤S FOV (Formula 2)

[0055] So we have:

[0056]

[0057] Where α is the field of view of the infrared measuring device. If it is a zoom system, the field of view is selected from the calibrated field of view of the device. If it is a fixed-focus system, it is a fixed field of view of the system. γ is the proportional coefficient of the area value of the high-temperature combustion product index occupying the image plane, and takes values ​​in the range of [1 / 2, 4 / 5]. tand is the tangent function. The observation gear refers to the observation field of view, integration time and attenuation plate gear of the infrared measuring device.

[0058] (3) According to the measurement requirements of the test plan, set the edge temperature threshold T of the equivalent blackbody temperature field of the high-temperature combustion product 0 (K).

[0059] (4) According to the ideal temperature measurement range of the infrared measurement equipment under different integration times and different transmittance attenuation sheet positions sorted out in step (1), select the ideal temperature measurement range covering the edge temperature threshold T 0 (K) The infrared measurement equipment observation gear (i.e., integration time, attenuation film transmittance gear), and the infrared measurement equipment is configured to measure the equivalent black body temperature of high-temperature combustion products greater than the edge temperature threshold T 0The area of (K).

[0060] (5) Use the infrared measurement device after gear configuration to perform imaging observation on the high-temperature combustion products, and obtain the infrared image of the high-temperature combustion products.

[0061] (6) Based on Planck's law and the system calibration result, calculate the blackbody temperature as the edge temperature threshold T 0 The corresponding edge gray threshold G of the high-temperature combustion product target area 0 , and the specific step method is as follows:

[0062] (6.1) Based on Planck's law, calculate the infrared radiation luminance L of the blackbody with a temperature of the edge temperature threshold T 0 within the working band; Planck's law can be expressed as:

[0063]

[0064] In the formula, M λ is the spectral radiant emittance of the blackbody, W·cm -2 ·μm; λ is the wavelength, μm; h is Planck's constant, 6.6256×10 -23 μm·s 2 ; T is the blackbody temperature, K, take the edge temperature threshold T 0 , that is, T = T 0 ; c is the speed of light, 2.997925×10 10 cm·s -1 ; k is the Boltzmann constant, 1.38054×10 -10 W·s -1 ·K -1 ;

[0065] The infrared radiation luminance L of the blackbody with a temperature of the edge temperature threshold T 0 within the working band [λ 1 , λ 2 can be calculated according to the following formula:

[0066]

[0067] (6.2) Based on the system parameters (K, B) of this observation gear and the atmospheric transmittance τ under the observation conditions, calculate the corresponding edge gray threshold G of the high-temperature combustion product target area with a blackbody temperature of the edge temperature threshold T 0 : 0

[0068] G 0 = τKL + B (Formula 6);

[0069] (6.3) Statistically analyze the maximum value G of the background before target combustion background ​With the time fluctuation value ΔG, perform edge grayscale threshold checking and correction accordingly:

[0070]

[0071] (7) Based on the edge grayscale threshold G of the image 0 Perform target area extraction algorithm processing to extract the pixel area where the equivalent blackbody temperature in the temperature field is higher than the edge temperature threshold T 0 and obtain the total number N of pixel points in the target area of high-temperature combustion products where the equivalent blackbody temperature is higher than the edge temperature threshold T 0 .

[0072] (8) Combine the observation parameters and observation distance of the infrared measurement device to calculate the instantaneous field of view coverage area S of the infrared measurement device at the target IFOV ;

[0073] S IFOV = S FOV / (m × n) = (2tan(α / 2)R) 2 / (m × n) (Formula 8)

[0074] where m × n represents the detector specification of the infrared measurement device.

[0075] (9) Calculate the infrared area S where the equivalent blackbody temperature in the high-temperature combustion products is higher than the edge temperature threshold T 0 :

[0076] S = N × S IFOV (Formula 9).

[0077] The setting basis of the edge temperature threshold T of the equivalent blackbody temperature field of high-temperature combustion products 0 is the measurement requirements of the test plan, including the assignment based on the ambient temperature and the assignment method based on the target infrared radiation intensity constraint.

[0078] When performing target area extraction algorithm processing based on the edge grayscale threshold G of the image 0 it includes the wavegate tracking and threshold segmentation image processing algorithms based on the miss distance.

Claims

1. A method for evaluating the infrared area characteristics of high-temperature combustion products based on the large dynamic temperature field distribution characteristics, characterized by: This method is based on the large dynamic temperature field distribution characteristics of high-temperature combustion products in the air, introduces Planck's law into the infrared area characteristic evaluation of high-temperature combustion products, and converts the corresponding target area edge grayscale threshold G0 by setting the edge temperature threshold T0 of the equivalent blackbody temperature field. Then, the target area extraction algorithm is used to extract the image pixel area and pixel number N where the equivalent blackbody temperature in the temperature field is higher than the edge temperature threshold T0. Then, the infrared area S of the high-temperature combustion product target area where the equivalent blackbody temperature is higher than the edge temperature threshold T0 can be calculated according to the observation parameters.

2. The method for evaluating infrared area characteristics of high temperature combustion products based on large dynamic temperature field distribution characteristics according to claim 1, characterized in that: The specific steps include: (1) Perform system calibration on the infrared measurement equipment used for the area characteristics evaluation of high-temperature combustion products, obtain system calibration parameters, and combine the calibration experimental data to sort out the ideal temperature measurement range of the infrared measurement equipment under different integration times and different transmittance attenuation sheet positions; (2) Select the observation distance and field of view according to the measurement requirements of the high-temperature combustion product area characteristics to be evaluated and the parameters of the infrared measurement equipment; (3) According to the measurement requirements of the test plan, set the edge temperature threshold T0 (K) of the equivalent blackbody temperature field of high-temperature combustion products; (4) According to the ideal temperature measurement range of the infrared measurement equipment under different integration times and different transmittance attenuation plate gear conditions sorted out in (1), the observation gear of the infrared measurement equipment whose ideal temperature measurement range covers the edge temperature threshold T0 (K), i.e., the integration time and attenuation plate transmittance gear, is selected, and the gear of the infrared measurement equipment is configured to measure the area where the equivalent blackbody temperature of the high-temperature combustion product is greater than the edge temperature threshold T0 (K); (5) Using the infrared measuring equipment after the gear configuration to observe the high-temperature combustion products and obtain the infrared image of the high-temperature combustion products; (6) Based on Planck's law and the system calibration results, the grayscale threshold G0 of the high-temperature combustion product target area corresponding to the black body temperature being the edge temperature threshold T0 is calculated; (7) performing target region extraction algorithm processing based on the image edge grayscale threshold G0, extracting the pixel region whose equivalent black body temperature in the temperature field is higher than the edge temperature threshold T0, and obtaining the total number N of pixel points in the high-temperature combustion product target region whose equivalent black body temperature is higher than the edge temperature threshold T0; (8) Combine the observation parameters and observation distance of the infrared measurement equipment to calculate the instantaneous field of view coverage area S of the infrared measurement equipment at the target. IFOV ; S IFOV =S FOV / (m×n)=(2tand(α / 2)R) 2 / (m×n) (Formula 8) Where m×n represents the specifications of the infrared measurement equipment detector; S FOV is the field of view coverage of the external measurement equipment, m 2 ; α is the field of view of the infrared measuring device; R is the observation distance, m; (9) Calculate the infrared area S where the equivalent blackbody temperature in the high-temperature combustion products is higher than the edge temperature threshold T0: S=N×S IFOV (Formula 9).

3. The method for evaluating infrared area characteristics of high temperature combustion products based on large dynamic temperature field distribution characteristics according to claim 2, characterized in that: The specific steps of step (2) are as follows: (2.1) Determine the infrared area characteristic measurement requirements of the high-temperature combustion products to be evaluated, such as the infrared area S must meet the index: ≥ area value S T (m 2 ), where S T Indicates the lower limit of the area required by the indicator; (2.2) Reasonably select the field of view angle α (°) and observation distance R (m) of the infrared measurement equipment to ensure that the field of view coverage range S of the infrared measurement equipment FOV (m 2 ) satisfies γ·S FOV ≤S T ≤S FOV : S FOV = (2R×tand(α / 2)) 2 (Formula 1) γ·S FOV ≤S T ≤S FOV (Formula 2) So we have: Where α is the field of view of the infrared measuring device. If it is a zoom system, the field of view is selected from the calibrated field of view of the device. If it is a fixed-focus system, it is a fixed field of view of the system. γ is the proportional coefficient of the area value of the high-temperature combustion product index occupying the image plane, and takes values ​​in the range of [1 / 2, 4 / 5]. tand is the tangent function. The observation gear refers to the observation field of view, integration time and attenuation plate gear of the infrared measuring device.

4. The method for evaluating infrared area characteristics of high temperature combustion products based on large dynamic temperature field distribution characteristics according to claim 3 is characterized in that: The specific steps of step (6) are as follows: (6.1) Based on Planck’s law, the infrared radiation brightness L of a black body with a temperature equal to the edge temperature threshold T0 in the working band is calculated; Planck’s law can be expressed as: Where M λ is the blackbody spectral radiation emittance, W·cm -2 ·μm; λ is the wavelength, μm; h is Planck's constant, 6.6256×10 -23 μm·s 2 ; T is the black body temperature, K, the edge temperature threshold T0 is taken, that is, T = T0; c is the speed of light, 2.997925×10 10 cm·s -1 ; k is the Boltzmann constant, 1.38054×10 -10 W.s -1 ·K -1 ; The infrared radiation brightness L of a black body with a temperature of the edge temperature threshold T0 in the working band [λ1,λ2] can be calculated according to the following formula: (6.2) Based on the system parameters (K, B) of the observation gear and the atmospheric transmittance τ under the observation conditions, the edge grayscale threshold G0 of the high-temperature combustion product target area corresponding to the blackbody temperature being the edge temperature threshold T0 is calculated: G0 = τKL + B (Formula 6); (6.3) Statistical target combustion background maximum value G background And the time fluctuation value ΔG, to check and correct the edge gray threshold:

5. The method for evaluating infrared area characteristics of high temperature combustion products based on large dynamic temperature field distribution characteristics according to claim 4, characterized in that: The edge temperature threshold T0 of the equivalent blackbody temperature field of high-temperature combustion products is set based on the measurement requirements of the test plan, including assignment methods based on ambient temperature and assignment methods based on target infrared radiation intensity constraints.

6. The method for evaluating infrared area characteristics of high temperature combustion products based on large dynamic temperature field distribution characteristics according to claim 5, characterized in that: When the target area extraction algorithm is processed based on the image edge grayscale threshold G0, it includes gate tracking and threshold segmentation image processing algorithms based on the miss amount.

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