Method and equipment for constructing measurement unit of infrared spectrum video equipment

Abstract

The embodiment of the invention provides a method and equipment for constructing a measurement unit of infrared spectrum video equipment, and belongs to the technical field of infrared spectrum imaging. The method comprises the following steps: setting a plurality of gas concentration, gas temperature and surface radiation source temperature combinations; based on a three-layer infrared radiation transmission model, obtaining theoretical radiation intensity corresponding to each combination, and recording the theoretical radiation intensity as a first corresponding relation; collecting the pixel value of the infrared spectrum video equipment at each surface radiation source temperature, and calculating the corresponding integral radiation intensity; fitting each pixel value and the integral radiation intensity to obtain a second corresponding relation between the pixel value and the integral radiation intensity; based on the first corresponding relation and the second corresponding relation, obtaining a third corresponding relation between the pixel value and the gas concentration under different gas temperatures and surface radiation source temperatures; and converting the gas concentration in the third corresponding relation into a standard volume. The method is used for solving the problem that errors exist in measurement results due to the fact that an existing measurement unit does not consider environmental factors.

Description

Technical Field

[0001] The present invention relates to the field of infrared spectrum imaging technology, and in particular to a method and device for constructing a measurement unit of infrared spectrum video equipment. Background Art

[0002] As a leading global chemical producer, my country faces a challenging production safety situation. Fire and explosion accidents caused by leaked gases remain a high percentage, posing a significant risk to industrial safety. Against this backdrop, the development of efficient and accurate gas leak detection technology is crucial. Infrared spectroscopy video imaging, an innovative solution in this area, integrates advanced infrared spectroscopy analysis with intelligent video surveillance to create a comprehensive monitoring system with real-time monitoring, rapid identification, and intelligent early warning capabilities. This technology enables visual tracking and precise location of leaking gases, providing a scientific basis for emergency response decisions and effectively enhancing the inherent safety of chemical companies.

[0003] The performance of infrared video equipment used in infrared spectroscopy imaging technology significantly impacts gas imaging and detection. Existing performance testing methods for infrared video measurement and control systems are based on thermal imagers, with measurement units of ppm·m or vol%·m. Performance indicators include noise equivalent temperature difference (NETD), minimum resolvable temperature difference (MRTD), minimum detectable temperature difference (MDTD), and maximum temperature measurement range.

[0004] However, when measuring gases based on existing measurement units, environmental factors such as gas temperature and background radiation are not considered, resulting in errors in the measurement results. Furthermore, existing performance indicators have a poor correlation with measurement units, making them inadequate for simulating the sensitivity and performance of infrared spectroscopy equipment under various gas concentrations at different ambient temperatures. Therefore, testing the performance of infrared spectroscopy equipment based on existing performance indicators is subject to issues such as imperfect testing methods and insufficient testing scenarios. This leads to a variety of potential errors in testing the performance of infrared spectroscopy equipment under different gas concentrations and temperatures.

[0005] Therefore, the measurement units and performance tests of existing infrared spectroscopy video equipment have certain defects. Summary of the Invention

[0006] The purpose of the embodiments of the present invention is to provide a method and device for constructing a measurement unit of an infrared spectroscopy video device, so as to solve the problem that the existing measurement units do not take environmental factors into consideration, resulting in errors in the measurement results.

[0007] In order to achieve the above-mentioned objectives, in a first aspect, an embodiment of the present invention provides a method for constructing a measurement unit of an infrared spectral video device, the method comprising: obtaining multiple combinations of gas concentrations, gas temperatures and surface radiation source temperatures based on a set plurality of gas concentrations, gas temperatures and surface radiation source temperatures; obtaining a theoretical radiation intensity received by the infrared spectral video device corresponding to each combination based on each of the combinations and a pre-established three-layer infrared radiation transmission model, recorded as a first corresponding relationship; collecting pixel values ​​of the infrared spectral video device at each of the surface radiation source temperatures, and calculating the corresponding integrated radiation intensity; fitting each of the pixel values ​​and the integrated radiation intensity to obtain a second corresponding relationship between the pixel value and the integrated radiation intensity; obtaining the pixel value corresponding to each of the combinations based on the first and second corresponding relationships, thereby obtaining a third corresponding relationship between the pixel value and the gas concentration at different gas temperatures and surface radiation source temperatures; and converting the gas concentration in the third corresponding relationship into a standard volume, thereby completing the construction of the measurement unit of the infrared spectral video device, the measurement unit being a standard volume, characterizing the standard volume of the gas corresponding to the pixel value of the gas detected by the infrared spectral video device.

[0008] Optionally, the standard volume is sL or Nm 3 .

[0009] Optionally, the set multiple gas concentrations, gas temperatures and surface radiation source temperatures include: multiple gas concentrations including 0.1%, 0.25%, 0.5% and 0.75%; multiple gas temperatures including multiple gas temperatures within the range of -20℃-50℃ obtained based on a preset first interval; and multiple surface radiation source temperatures including multiple gas temperatures within the range of 0℃-50℃ obtained based on a preset second interval.

[0010] Optionally, the pixel value of the infrared spectroscopy video device is an average value of total pixel values ​​collected by the infrared spectroscopy device based on a preset collection time, a preset first collection frequency and a preset collection area.

[0011] Optionally, the three-layer infrared radiation transmission model is:

[0012] in,

[0013]

[0014] in, is the radiation intensity received by the infrared spectrum video equipment; For the The transmittance of the layer, For the The radiation intensity of the layer, For the The temperature of the layer, and The first and third layers represent the filters at both ends of the measurement chamber of the infrared spectrum video measurement and control platform. represents the layer where the gas is located, is the layer where the surface radiation source is located; is the absorption coefficient of the gas; is the gas concentration; The length of the measurement chamber of the infrared spectrum video measurement and control platform; is Planck's first constant; is Planck's second constant; is the wavelength selected in the radiation band of the surface radiation source.

[0015] Optionally, based on each of the combinations and a pre-established three-layer infrared radiation transmission model, the theoretical radiation intensity received by the infrared spectrum video device corresponding to each combination is obtained, including: based on a preset step size, selecting multiple wavelengths in the radiation band of the surface radiation source; and for each of the combinations, performing the following operations: substituting the gas concentration, gas temperature, surface radiation source temperature and the multiple wavelengths in the combination into the three-layer infrared radiation transmission model to obtain the radiation intensity received by the infrared spectrum video device corresponding to the multiple wavelengths; integrating the radiation intensity received by the infrared spectrum video device corresponding to the multiple wavelengths to obtain the theoretical radiation intensity received by the infrared spectrum video device corresponding to the combination.

[0016] Optionally, the method for calculating the integrated radiation intensity corresponding to the temperature of each of the surface radiation sources includes: calculating the integrated radiation intensity based on an integrated radiation intensity formula, where the integrated radiation intensity formula is:

[0017] in, and are the two endpoints of the radiation band of the surface radiation source, is the surface radiation source temperature, is the Stefan-Boltzmann constant, is the integrated radiation intensity of the surface radiation source, For band 0 to The proportion of radiation in the entire band.

[0018] Optionally, the band 0 to The calculation formula for the proportion of radiation in the whole band is: .

[0019] Optionally, converting the gas concentration in the third corresponding relationship into a standard volume includes: substituting the gas concentration at different gas temperatures and the surface radiation source temperature into a standard volume formula to calculate the standard volume, where the standard volume formula is:

[0020] in, is the standard volume, is the gas concentration, is the filter window diameter of the infrared spectroscopy video measurement and control platform, is the distance between the infrared spectrum video equipment and the filter window.

[0021] In a second aspect, an embodiment of the present invention provides an infrared spectroscopy video device, wherein the measurement unit of the device is a standard volume, and the measurement unit is constructed based on any method for constructing a measurement unit of an infrared spectroscopy video device.

[0022] In a third aspect, an embodiment of the present invention provides a method for measuring the standard volume of a gas, which is performed by the infrared spectroscopy video device. The method includes: converting the radiation in the acquisition area into pixel values, where the acquisition area includes unknown gas; calculating the integrated radiation intensity of the surface radiation source based on the radiation band of the surface radiation source, the gas temperature, and the surface radiation source temperature. , the integrated radiation intensity received by the infrared spectrum video device And the integrated radiation intensity corresponding to the temperature of the radiation of the filters at both ends of the measuring chamber and ; The calculated 、 、 and Substitute the inversion model of the three-layer infrared radiation transmission model to calculate the concentration of the unknown gas. The inversion model is:

[0023] in, is the concentration of the unknown gas, is the absorption coefficient of the gas; and converting the concentration of the unknown gas into a standard volume based on the standard volume formula.

[0024] The proposed measurement unit for infrared spectroscopy video equipment can convert received pixel values ​​into standard volumes of gas. When measuring gas based on this measurement unit, different pixel values ​​detected at different gas temperatures and surface radiation source temperatures can yield different measurement results, thus helping to avoid errors when infrared spectroscopy video equipment detects gases of varying concentrations in different environments.

[0025] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of the infrared spectroscopy video measurement and control platform provided by an embodiment of the present invention; Figure 2 It is a flowchart of a method for constructing a measurement unit of an infrared spectroscopy video device provided by an embodiment of the present invention; Figure 3 Schematic diagram of the structure of a three-layer infrared radiation transmission model provided by an embodiment of the present invention; Figure 4 1 is a flow chart of a method for testing the performance of an infrared spectroscopy video device provided by an embodiment of the present invention; Figure 5 This is a schematic diagram of the collection area provided by an embodiment of the present invention.

[0027] Description of Reference Numerals 1Infrared spectroscopy video equipment 2Independent measurement chamber 3 blackbody light sources 4 jackets 5 filter 6 dangerous gas concentration detector 7 Temperature transmitter 8 Pressure transmitter 9 Hot and cold integrated machine 10 Gas storage tank to be tested 11 Inert diluent gas or air storage tank 12 Pressure regulating valve 13 filter 14a first flow controller 14b Second flow controller 15 Dangerous gas filling valve 16 Gas mixing pipeline 17 Emptying and circulation pipeline 18 Exhaust line 19 Pressure control valve 20 Safety valve 21 Gas absorption device 22 Gas mixer 23 Heat exchanger 24 Vacuum pump 25 Gas filling pipeline 26 Control terminal 27 Oxygen concentration detector 28 Inert diluent gas or air filling valve DETAILED DESCRIPTION The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0028] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application are in compliance with the relevant provisions of laws and regulations. In the embodiments of this application, certain software, components, models, and other existing solutions in the industry may be mentioned. These should be considered as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of this application, but it does not mean that the applicant has or will necessarily use such solutions.

[0029] To address the problem that existing measurement units do not take into account the impact of environmental factors, the present invention proposes a new measurement unit for infrared spectroscopy video equipment. When constructing this measurement unit, an infrared spectroscopy video measurement and control platform is used to acquire data.

[0030] Figure 1 FIG. 1 is a schematic diagram of the structure of the infrared spectrum video measurement and control platform provided by an embodiment of the present invention. Figure 1 As shown, the platform is equipped with a detachable independent measurement chamber 2 between the blackbody light source 3 and the infrared spectrum video device 1. By different combinations of different numbers of independent measurement chambers 2, measurement chambers of different lengths can be obtained, which is used to solve the problems of short adjustable chamber length or fixed length in the prior art. By using a series of subsystems such as air intake, replacement, circulation, heating and safe discharge, the automation operation of the entire platform is improved, which greatly meets the simulation test in multiple occasions and can greatly improve the accurate evaluation and calibration capabilities of the performance of the infrared spectrum video device 1.

[0031] Figure 2 FIG. 1 is a flow chart of a method for constructing a measurement unit of an infrared spectroscopy video device according to an embodiment of the present invention. Figure 2 As shown, the method includes the following steps S101 to S106.

[0032] Step S101: Based on a plurality of set gas concentrations, gas temperatures and surface radiation source temperatures, a plurality of gas concentration, gas temperature and surface radiation source temperature combinations are obtained.

[0033] Step S102: Based on each of the combinations and a pre-established three-layer infrared radiation transmission model, a theoretical radiation intensity received by the infrared spectrum video device corresponding to each of the combinations is obtained, which is recorded as a first corresponding relationship.

[0034] Step S103: collecting pixel values ​​of the infrared spectrum video device at each of the surface radiation source temperatures, and calculating the corresponding integrated radiation intensity.

[0035] Step S104: fitting each of the pixel values ​​and the integrated radiation intensity to obtain a second corresponding relationship between the pixel value and the integrated radiation intensity.

[0036] Step S105: Based on the first corresponding relationship and the second corresponding relationship, the pixel value corresponding to each combination is obtained, thereby obtaining a third corresponding relationship between the pixel value and the gas concentration under different gas temperatures and surface radiation source temperatures.

[0037] Step S106: Convert the gas concentration in the third corresponding relationship into a standard volume, thereby completing the construction of the measurement unit of the infrared spectroscopy video device. The measurement unit is a standard volume, which represents the standard volume of the gas corresponding to the pixel value of the gas detected by the infrared spectroscopy video device.

[0038] The measurement unit of the infrared spectroscopy video device proposed in this invention converts received pixel values ​​into standard volumes of gas. Based on this measurement unit, different measurement results can be obtained for the pixel values ​​of gas detected at different gas temperatures and surface radiation source temperatures, thus helping to avoid errors when the infrared spectroscopy video device detects gases of varying concentrations in different environments.

[0039] Furthermore, the standard volume is sL or Nm 3 .

[0040] In some embodiments of the present invention, the set multiple gas concentrations, gas temperatures and surface radiation source temperatures include: multiple gas concentrations including 0.1%, 0.25%, 0.5% and 0.75%; multiple gas temperatures including multiple gas temperatures within the range of -20℃-50℃ obtained based on a preset first interval; and multiple surface radiation source temperatures including multiple gas temperatures within the range of 0℃-50℃ obtained based on a preset second interval.

[0041] The first interval can be set to 12.5° C., and the second interval can be set to 10° C. The settings of gas concentration, gas temperature, and surface radiation source temperature can be adjusted according to actual conditions and are not limited to the setting ranges proposed in the present invention.

[0042] Furthermore, the pixel value of the infrared spectroscopy video device is an average value of total pixel values ​​collected by the infrared spectroscopy device based on a preset collection time, a preset first collection frequency and a preset collection area.

[0043] Figure 3 is a schematic structural diagram of a three-layer infrared radiation transmission model provided by an embodiment of the present invention, such as Figure 3 As shown in , the three-layer infrared radiation transmission model is simplified from the multi-layer infrared radiation transmission model. Figure 3As shown in the figure, there is a closed air chamber in the middle, with a surface radiation source as the background and an infrared spectrum video device for receiving radiation at both ends. The closed air chamber is divided into three layers. The model assumes that the entire path between the background and the infrared spectrum video device can be divided into a series of parallel layers, and each layer calculates the input radiation intensity of the previous layer and the output radiation intensity of the next layer. , its output radiation intensity is a function of wavelength and temperature, given by the previous layer Radiation absorption and The three-layer infrared radiation transmission model is:

[0044] in,

[0045]

[0046] in, is the radiation intensity received by the infrared spectrum video device (W / m²); For the The transmittance of the layer, For the Radiant intensity of the layer (W / m²), For the Temperature of the layer (K), and The first and third layers represent the filters at both ends of the measurement chamber of the infrared spectrum video measurement and control platform. represents the layer where the gas is located, is the layer where the surface radiation source is located; is the absorption coefficient of the gas; is the gas concentration; is the measurement chamber length of the infrared spectroscopy video measurement and control platform (m); is Planck's first constant, ; is Planck's second constant, ; is the wavelength selected in the radiation band of the surface radiation source.

[0047] When performing calculations based on the three-layer infrared radiation transmission model, the transmittance of the filter and gas, as well as the absorption coefficient of the gas, can be obtained by referring to existing technologies. Since the filters at both ends of the measurement chamber are in direct contact with the gas, the temperature of the filter is the same as the gas temperature.

[0048] Furthermore, based on each of the combinations and a pre-established three-layer infrared radiation transmission model, the theoretical radiation intensity received by the infrared spectrum video device corresponding to each combination is obtained, including: based on a preset step size, selecting multiple wavelengths in the radiation band of the surface radiation source; and for each of the combinations, performing the following operations: substituting the gas concentration, gas temperature, surface radiation source temperature and the multiple wavelengths in the combination into the three-layer infrared radiation transmission model to obtain the radiation intensity received by the infrared spectrum video device corresponding to the multiple wavelengths; integrating the radiation intensity received by the infrared spectrum video device corresponding to the multiple wavelengths to obtain the theoretical radiation intensity received by the infrared spectrum video device corresponding to the combination.

[0049] In some embodiments of the present invention, the wavelength band of the surface radiation source is 9.4μm~11.7μm. In order to improve the accuracy of the integration, the step size should be set as small as possible. For example, if it is set to 0.00001μm, the multiple wavelengths selected are 9.40000μm, 9.40001μm, 9.40001μm, ..., 11.70000μm. For a combination of a certain gas concentration, gas temperature and surface radiation source temperature, multiple , and then use the adjacent wavelengths as the upper and lower limits to calculate the multiple The theoretical radiation intensity received by the infrared spectrum video device corresponding to the combination is obtained by integration.

[0050] To eliminate the effects of optical path length (chamber length) and air on radiation intensity, the surface radiation source is placed directly in close contact with the infrared spectroscopy video device 1, and the temperature of the surface radiation source is adjusted. The corresponding pixel values ​​of the infrared spectroscopy video device 1 are collected, thereby more accurately obtaining the correspondence between the pixel values ​​and the actual radiation intensity. The actual radiation intensity corresponding to each surface radiation source temperature can be calculated by integration. The method for calculating the integrated radiation intensity corresponding to each surface radiation source temperature includes: calculating the integrated radiation intensity based on the integrated radiation intensity formula, which is:

[0051] in, and They are the two endpoints of the radiation band of the surface radiation source. When the band of the surface radiation source is 9.4μm~11.7μm, The value is 9.4μm, The value is 11.7μm; is the surface radiation source temperature (K); is the Stefan-Boltzmann constant, ; is the integrated radiation intensity of the surface radiation source (W / m²); For band 0 to The ratio of radiation to the radiation of the entire band can be obtained by calculation or by looking up the blackbody radiation function table, as shown in Table 1.

[0052] Table 1 Radiation function table of surface radiation source

[0053] Obtained by calculation When the band 0 to The calculation formula for the proportion of radiation in the whole band is: .

[0054] Furthermore, converting the gas concentration in the third corresponding relationship into a standard volume includes: substituting the gas concentration at different gas temperatures and the surface radiation source temperature into a standard volume formula to calculate the standard volume, wherein the standard volume formula is:

[0055] in, is the standard volume (scm), is the gas concentration, is the filter window diameter of the infrared spectroscopy video measurement and control platform (m), is the distance between the infrared spectrum video device and the filter window (m). It should be noted that scm and Nm 3 They have the same meaning and both represent standard cubic meters.

[0056] An embodiment of the present invention further provides an infrared spectrum video device, wherein the measurement unit of the device is a standard volume, and the measurement unit is constructed based on any one of the methods described above.

[0057] An embodiment of the present invention further provides a method for measuring the standard volume of gas, which is performed by infrared spectroscopy video equipment and includes the following steps S201 to S204.

[0058] Step S201: converting radiation within a collection area into pixel values, wherein the collection area includes unknown gas.

[0059] Step S202: Calculate the integrated radiation intensity of the surface radiation source based on the radiation band of the surface radiation source, the gas temperature and the surface radiation source temperature. , the integrated radiation intensity received by the infrared spectrum video device And the integrated radiation intensity corresponding to the temperature of the radiation of the filters at both ends of the measuring chamber and .

[0060] Step S203: The calculated 、 、 and Substitute the inversion model of the three-layer infrared radiation transmission model to calculate the concentration of the unknown gas. The inversion model is:

[0061] in, is the concentration of the unknown gas, is the absorption coefficient of the gas.

[0062] Step S204: converting the concentration of the unknown gas into a standard volume based on a standard volume formula.

[0063] It should be noted that if the infrared spectrum video device is used for actual measurement, when the integral radiation intensity formula is used to calculate each integral radiation intensity, the surface radiation source temperature is the measured background temperature, the temperature received by the infrared spectrum video device is the measurement value of the device when the gas appears, and the temperature of the radiation of the filters at both ends of the measurement chamber is the ambient temperature. and The average value is a fixed value, for example, the average value is 1, is the distance between the infrared spectroscopy device and the actual background. This formula is more suitable for testing device performance in a laboratory environment. In actual applications, the environment is more complex and factors such as solid particles and water vapor in the air need to be considered. To obtain more accurate results, the formula can be adjusted according to the actual environment.

[0064] Figure 4 FIG. 1 is a flow chart of a method for testing the performance of an infrared spectroscopy video device according to an embodiment of the present invention. Figure 4 As shown, the method includes the following steps S301-S306.

[0065] Step S301: Start the infrared spectrum video measurement and control platform and the infrared spectrum video device to obtain the field of view of the infrared spectrum video device.

[0066] Step S302: selecting a collection area in the field of view of the infrared spectrum video device.

[0067] Step S303: Based on the gas and its concentration required for performance testing, the gas is filled into the measurement gas chamber of the infrared spectrum video measurement and control platform.

[0068] Step S304: adjusting the infrared spectrum video measurement and control platform to simulate the environment required for performance testing.

[0069] Step S305: collecting a first response value of the infrared spectrum video device in the environment.

[0070] Step S306: Calculating a performance test result of the infrared spectroscopy video device based on the first response value.

[0071] The performance test includes zero point calculation, range test, indication error calculation, sensitivity test, detection limit test, repeatability test and / or drift test.

[0072] It should be noted that during the performance test, the test environment should be kept at a constant temperature. The infrared spectroscopy video equipment should be started for at least 10 minutes before the test. The movement temperature should be continuously recorded during the test. For non-cooled infrared spectroscopy video equipment, the movement temperature should be kept stable.

[0073] The measurement unit proposed in this invention is closely related to gas temperature and the temperature of the surface radiation source. When performing performance testing on infrared spectroscopy video equipment using this measurement unit, the effects of gas temperature and the surface radiation source temperature must be considered. The method for testing infrared spectroscopy video equipment performance proposed in this invention utilizes an infrared spectroscopy video measurement and control platform to simulate gas concentrations and the required environment. This allows for more convenient and accurate evaluation of infrared spectroscopy video equipment system performance, helping to avoid issues such as imperfect testing methods and insufficient detection scenarios that exist in existing performance testing. It also reduces the various potential errors associated with infrared spectroscopy video equipment performance testing at different gas concentrations and temperatures.

[0074] Furthermore, selecting a collection area in the field of view of the infrared spectroscopy video device includes: selecting a preliminary area, the preliminary area being an area in the field of view where a filter on the surface radiation source side is located; determining a center position of the preliminary area; and obtaining the collection area based on the center position and a preset size, wherein the collection area is within the preliminary area.

[0075] Figure 5 is a schematic diagram of the collection area provided by an embodiment of the present invention, such as Figure 5 As shown, within the field of view of the infrared spectroscopy video device, the center of the filter outline on the surface radiation source side is determined as the center of the circle. A collection area is then obtained based on a preset diameter, such as 10 cm. Alternatively, the collection area can be obtained by directly using the filter outline on the surface radiation source side as the circumscribed circle.

[0076] Furthermore, collecting the first response value of the infrared spectroscopy video device under the environment includes: obtaining the pixel value of each pixel point in the collection area based on a preset collection duration and a preset first collection frequency; calculating the average value of the total collected pixel values; and converting the average value of the pixel values ​​into a standard volume to obtain the first response value.

[0077] It should be noted that the environment should be stable for at least 45 seconds before sampling. The preset sampling time is not less than 2 seconds, and the preset first sampling frequency is not less than 1 time / s.

[0078] Furthermore, the gases required for the performance test include: a test gas, including the test gas specified on the infrared spectroscopy video device or a test gas selected based on the device type, where the device type includes refrigerated and non-refrigerated devices; and a zero-point gas, including clean air or nitrogen, where clean air is air free of the test gas. The test gas can be methane, ethane, ethylene, or propylene. If the device does not specify the test gas type, a methane gas standard substance can be used for refrigerated devices, and an ethylene gas standard substance can be used for non-refrigerated devices. The concentration of the standard substance ranges from 0.1% to 100% LEL (Lower Explosive Limit). The test gas storage tank 10 can be directly filled with the gas to meet the required concentration, or the test gas storage tank 10 in the infrared spectroscopy video measurement and control platform can be mixed with the gas in the inert diluent gas or air storage tank 11 to obtain the required gas concentration.

[0079] Furthermore, based on the gas required for performance testing and its concentration, the gas is filled into the measuring gas chamber of the infrared spectroscopy video measurement and control platform, including: if the required gas is the gas to be tested, adjusting the first flow controller and the second flow controller in the infrared spectroscopy video measurement and control platform to obtain the required concentration of the gas to be tested in the gas mixer, and passing the gas in the gas mixer into the measuring gas chamber; and if the required gas is the zero-point gas, adjusting the second flow controller in the infrared spectroscopy video measurement and control platform to obtain the zero-point gas, and passing the zero-point gas into the measuring gas chamber.

[0080] Furthermore, the zero point calculation includes: filling the measurement chamber of the infrared spectroscopy video measurement and control platform with the zero point gas, adjusting the gas temperature to a preset first gas temperature and maintaining the gas pressure at the preset first gas pressure to simulate atmospheric pressure; adjusting the surface radiation source temperature to a preset first surface radiation source temperature; and collecting first response values ​​based on a preset first collection number of times and taking an average value to obtain the zero point of the device. The preset first collection number can be three, the preset first gas temperature can be 0°C, the preset first gas pressure can be 101.3kPa±1kPa to simulate atmospheric pressure, and the preset first surface radiation source temperature can be 5°C±0.1°C, and can also be adjusted based on the actual situation of the infrared spectroscopy video device to be tested.

[0081] Furthermore, the range test includes: adjusting the temperature of the surface radiation source to a preset first surface radiation source temperature; filling the gas to be measured into the measuring gas chamber of the infrared spectroscopy video measurement and control platform, adjusting the gas temperature to the preset first gas temperature and continuously increasing the concentration of the gas to be measured in the measuring gas chamber until the response value of the infrared spectroscopy video device no longer changes; collecting the first response value as the full-scale response value; calculating the full-scale gas cloud standard volume of the gas to be measured in the measuring gas chamber; and based on the full-scale response value and the full-scale gas cloud standard volume, obtaining the result of the range test, that is, the correspondence between the full-scale response value and the full-scale gas cloud standard volume. Wherein, the calculation formula of the full-scale gas cloud standard volume is:

[0082] in, is the standard volume of full-scale gas cloud (scm), is the length of the measuring chamber (m), is the horizontal field of view angle of the infrared lens (°), is the vertical field of view angle of the infrared lens (°). is the maximum imaging distance (m). Please refer to the data given in the instruction manual of the infrared spectroscopy video equipment. It is the concentration corresponding to the full-scale gas cloud standard volume, that is, the concentration when the response value of the infrared spectrum video equipment no longer changes.

[0083] Furthermore, the indication error calculation includes: selecting at least three concentrations of the gas to be tested based on a certain concentration interval within the concentration range corresponding to the standard volume of the gas cloud from 0 to the full scale of the gas to be tested. The three representative concentrations selected should include low, medium and high concentration points, such as the concentrations corresponding to 10%, 30% and 50% of the range, to verify the error characteristics of the equipment at different concentrations. For each selected gas to be tested, the following operations are performed: The gas to be tested is filled into the measurement chamber of the infrared spectroscopy video measurement and control platform, while the gas temperature is adjusted to a preset first gas temperature and the gas pressure is maintained at the preset first gas pressure. The gas temperature and the surface radiation source temperature are adjusted to two different groups, wherein the gas temperature of the first group is the preset first gas temperature and the surface radiation source temperature is the preset first surface radiation source temperature, and the gas temperature of the second group is the preset second gas temperature and the surface radiation source temperature is the preset second surface radiation source temperature. For each group, first response values ​​are collected based on a preset first number of collections and averaged. An error value is calculated for each group. The preset second gas temperature can be 5°C, and the preset second surface radiation source temperature can be 30°C±0.1°C. These can also be adjusted based on the actual conditions of the infrared spectroscopy video equipment to be tested.

[0084] Finally, the error value with the largest absolute value among all the calculated error values ​​is selected as the indication error. The calculation formula for the error value of each group is:

[0085]

[0086] in, The error value (scm) calculated for the group, The mean (scm) calculated for the group, is the standard volume (scm) of the gas to be measured in the measuring chamber, is the concentration of the gas to be measured (vol%), is the filter window diameter of the infrared spectroscopy video measurement and control platform (m), is the distance between the infrared spectrum video device and the filter window (m).

[0087] Furthermore, the sensitivity detection includes: selecting a gas to be tested of a preset first concentration (e.g., 1 / 8 LEL) and a preset second concentration (e.g., 1 / 4 LEL), respectively, and performing the following operations for each selected gas to be tested: filling the gas to be tested into a measurement gas chamber of the infrared spectroscopy video measurement and control platform, while adjusting the gas temperature to a preset first gas temperature and maintaining the gas pressure at the preset first gas pressure; adjusting the temperature of the surface radiation source to a preset second surface radiation source temperature; collecting first response values ​​based on a preset first number of collections and taking an average value; and calculating the sensitivity based on the calculated average value, using the following calculation formula:

[0088] in, is the sensitivity, is the average value of the first response value corresponding to the gas to be tested with a preset first concentration, is the average value of the first response value corresponding to the gas to be measured with the preset second concentration, The standard volume of the gas to be measured in the gas chamber is measured when the first concentration of the gas to be measured is preset. The standard volume of the gas to be measured in the gas chamber when the second concentration of the gas to be measured is preset, and the units of the parameters in this formula are all scm.

[0089] Furthermore, the detection limit detection includes: filling the zero-point gas into the measurement gas chamber of the infrared spectroscopy video measurement and control platform, while adjusting the gas temperature to a preset first gas temperature and maintaining the gas pressure at the preset first gas pressure; adjusting the gas temperature and the surface radiation source temperature so that the two maintain a preset temperature difference, for example, if the preset temperature difference is 30°C, the gas temperature is adjusted to 0°C, and the surface radiation source temperature is adjusted to 30°C; collecting a first response value based on a preset second acquisition frequency and a preset second acquisition number, and calculating the system noise, the calculation formula is:

[0090] in, is the system noise, To preset the second acquisition times, is the first response value of a single acquisition, for The second acquisition number may be 10 times, and the second acquisition frequency may be once every 6 seconds.

[0091] Based on the sensitivity and the system noise, calculate the detection limit , the calculation formula is:

[0092] in, j To preset the discriminant coefficient, it can be selected according to the confidence interval, such as under 95% confidence level, j =3, the confidence interval can be set according to actual conditions.

[0093] Furthermore, the repeatability test includes: based on a preset third acquisition number, for example, set to 6 times, repeating the following operations 6 times: filling the selected preset second concentration of the gas to be tested into the measuring gas chamber of the infrared spectroscopy video measurement and control platform, while adjusting the gas temperature to the preset first gas temperature and maintaining the gas pressure at the preset first gas pressure; adjusting the gas temperature to the preset second gas temperature and adjusting the surface radiation source temperature to the preset second surface radiation source temperature; collecting the first response value; and removing the gas to be tested.

[0094] The relative standard deviation is calculated based on the first response value collected. The calculation formula is:

[0095] in, is the relative standard deviation, To preset the third collection number, For the The first response value (scm) of the acquisition, for The mean (SCM) of the first response values ​​collected over the past 100 measurements. The relative standard deviation (RSD) is a key indicator for measuring device repeatability, directly reflecting the device's measurement stability under fixed conditions. The results can be used to determine whether the device meets operating requirements and provide a basis for subsequent maintenance or calibration.

[0096] Furthermore, the drift test includes: operating the infrared spectroscopy video device continuously for a preset time, and repeatedly performing the following operations at a preset third acquisition frequency during the preset time: filling the measurement gas chamber of the infrared spectroscopy video measurement and control platform with the zero-point gas, adjusting the gas temperature to a preset first gas temperature and maintaining the gas pressure at the preset first gas pressure; adjusting the gas temperature to a preset second gas temperature and adjusting the surface radiation source temperature to a preset second surface radiation source temperature; acquiring a first response value, which is recorded as the zero-point response value; replacing the zero-point gas with a gas to be measured having a preset third concentration, adjusting the gas temperature to the preset second gas temperature and adjusting the surface radiation source temperature to a preset third surface radiation source temperature, for example, 25°C; acquiring a first response value, which is recorded as the test response value; and removing the gas to be measured. The third concentration may be a gas between 50% of the range and 100% of the range.

[0097] Based on the collected zero-point response values, the zero-point drift corresponding to each zero-point response value is calculated, and the maximum zero-point drift obtained by calculation is selected as the zero-point drift of the device. The calculation formula for the zero-point drift corresponding to each zero-point response value is:

[0098] in, is the number of collections, for The corresponding zero drift (scm), is the zero-point response value of a single acquisition (scm), is the zero-point response value (scm) collected for the first time, is the standard volume of full-scale gas cloud (scm).

[0099] Based on the collected zero response value and test response value, the span drift corresponding to each test response value is calculated, and the largest span drift obtained by calculation is selected as the span drift of the device. The calculation formula for the span drift corresponding to each test response value is:

[0100] in, for The corresponding range drift (scm), is the test response value (scm) of a single acquisition, is the test response value (scm) collected for the first time.

[0101] The performance inspection method proposed in the present invention is compatible with the infrared spectroscopy video measurement and control platform, can meet the simulation test requirements in most scenarios, saves a lot of manpower, material resources and time, and also provides a basis for the subsequent calibration and maintenance of infrared spectroscopy video equipment.

[0102] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0103] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A method for constructing a measurement unit of an infrared spectroscopy video device, characterized in that: The method comprises: Based on the set multiple gas concentrations, gas temperatures and surface radiation source temperatures, multiple gas concentration, gas temperature and surface radiation source temperature combinations are obtained; Based on each of the combinations and a pre-established three-layer infrared radiation transmission model, a theoretical radiation intensity received by the infrared spectrum video device corresponding to each of the combinations is obtained, which is recorded as a first corresponding relationship; Collecting pixel values ​​of the infrared spectrum video device at each of the surface radiation source temperatures and calculating the corresponding integrated radiation intensity; Fitting each of the pixel values ​​and the integrated radiation intensity to obtain a second corresponding relationship between the pixel value and the integrated radiation intensity; Based on the first corresponding relationship and the second corresponding relationship, a pixel value corresponding to each of the combinations is obtained, thereby obtaining a third corresponding relationship between the pixel value and the gas concentration at different gas temperatures and surface radiation source temperatures; and The gas concentration in the third corresponding relationship is converted into a standard volume, thereby completing the construction of the measurement unit of the infrared spectrum video device. The measurement unit is a standard volume, which represents the standard volume of the gas corresponding to the pixel value of the gas detected by the infrared spectrum video device.

2. The method according to claim 1, characterized in that The standard volume is in sL or Nm 3 .

3. The method according to claim 1, characterized in that The set multiple gas concentrations, gas temperatures and surface radiation source temperatures include: Multiple gas concentrations including 0.1%, 0.25%, 0.5% and 0.75%; The plurality of gas temperatures include a plurality of gas temperatures divided based on a preset first interval within a range of -20°C to 50°C; and The multiple surface radiation source temperatures include multiple gas temperatures within the range of 0° C. to 50° C. divided based on a preset second interval.

4. The method according to claim 1, wherein The pixel value of the infrared spectrum video device is an average value of total pixel values ​​collected by the infrared spectrum device based on a preset collection time, a preset first collection frequency and a preset collection area.

5. The method according to claim 1, characterized in that The three-layer infrared radiation transmission model is: in, in, is the radiation intensity received by the infrared spectrum video equipment; For the The transmittance of the layer, For the The radiation intensity of the layer, For the The temperature of the layer, and The first and third layers represent the filters at both ends of the measurement chamber of the infrared spectrum video measurement and control platform. represents the layer where the gas is located, is the layer where the surface radiation source is located; is the absorption coefficient of the gas; is the gas concentration; The length of the measurement chamber of the infrared spectrum video measurement and control platform; is Planck's first constant; is Planck's second constant; is the wavelength selected in the radiation band of the surface radiation source.

6. The method according to claim 5, characterized in that Based on each of the combinations and the pre-established three-layer infrared radiation transmission model, the theoretical radiation intensity received by the infrared spectrum video device corresponding to each of the combinations is obtained, including: Based on a preset step size, selecting multiple wavelengths in the radiation band of the surface radiation source; and For each of these combinations, do the following: Substituting the gas concentration, gas temperature, and surface radiation source temperature in the combination and the multiple wavelengths into a three-layer infrared radiation transmission model to obtain the radiation intensity received by the infrared spectrum video device corresponding to the multiple wavelengths; The radiation intensities received by the infrared spectrum video device corresponding to the multiple wavelengths are integrated to obtain the theoretical radiation intensity received by the infrared spectrum video device corresponding to the combination.

7. The method according to claim 5, characterized in that The calculation method of the integrated radiation intensity corresponding to the temperature of each surface radiation source includes: The integrated radiation intensity is calculated based on the integrated radiation intensity formula, which is: in, and are the two endpoints of the radiation band of the surface radiation source, is the surface radiation source temperature, is the Stefan-Boltzmann constant, is the integrated radiation intensity of the surface radiation source, For band 0 to The proportion of radiation in the entire band.

8. The method according to claim 7, characterized in that The band 0 to The calculation formula for the proportion of radiation in the whole band is: 。 9. The method according to claim 7, characterized in that Converting the gas concentration in the third correspondence into a standard volume includes: Substitute the gas concentration at different gas temperatures and surface radiation source temperatures into the standard volume formula to calculate the standard volume. The standard volume formula is: in, is the standard volume, is the gas concentration, is the filter window diameter of the infrared spectroscopy video measurement and control platform, is the distance between the infrared spectrum video equipment and the filter window.

10. An infrared spectrum video device, characterized in that: The measurement unit of the device is a standard volume, and the measurement unit is constructed based on the method according to any one of claims 1 to 9.

11. A method for measuring the standard volume of a gas, characterized in that: The method is performed by the infrared spectrum video device according to claim 10, and the method includes: Converting radiation within a collection area into pixel values, wherein the collection area includes unknown gas; Based on the radiation band, gas temperature and surface radiation source temperature of the surface radiation source, the integrated radiation intensity of the surface radiation source is calculated. , the integrated radiation intensity received by the infrared spectrum video device And the integrated radiation intensity corresponding to the temperature of the radiation of the filters at both ends of the measuring chamber and ; The calculated 、 、 and Substitute the inversion model of the three-layer infrared radiation transmission model to calculate the concentration of the unknown gas. The inversion model is: in, is the concentration of the unknown gas, is the absorption coefficient of the gas; and The concentration of the unknown gas is converted into standard volume based on the standard volume formula.

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