Detection method and system of ambient greenhouse gas monitor based on cavity enhancement

Abstract

The present invention relates to the field of cavity enhancement technology, and discloses a detection method and system of an environmental greenhouse gas monitor based on cavity enhancement, the method comprising: calculating the number of infrared rays in a reflection sample reflected back by an enhancement cavity in an integrated detector, and using the number of infrared rays to detect the infrared emission angle of the enhancement cavity; calculating the transmission length of the infrared sample in the enhancement cavity, constructing the placement position of the instrument component on the gas area, and placing the instrument component on the gas area through the placement position; calculating the sample error between the infrared sample and the reflection sample, adjusting the infrared wavelength of a single-frequency infrared laser, and using the adjusted wavelength to query the gas category of the gas to be detected; setting the integration time and average times of an infrared spectrometer, and using a spectrum to calculate the gas concentration of the gas to be detected; using the gas category and gas concentration as the gas detection result of the environmental greenhouse gas monitor. The present invention can realize the enhancement of infrared light under the premise of simplifying the gas detection system.

Description

Technical Field

[0001] The present invention relates to the field of cavity enhancement technology, and in particular to a detection method and system for an environmental greenhouse gas monitor based on cavity enhancement. Background Art

[0002] An enhancement cavity is an optical cavity (resonant cavity) that is used to resonate and enhance light power or light intensity. Infrared rays and the gas to be detected are transmitted to the enhancement cavity. The infrared rays enhanced by the enhancement cavity can be used to detect the gas concentration of the gas to be detected, thereby enabling the environmental greenhouse gas monitor to detect trace gas concentrations under the enhancement of the enhancement cavity.

[0003] At present, there are many methods for gas concentration detection based on enhanced cavity. For example, the infrared light beam generated by the light source is converted into a pulsed light beam through an optical modulator, and the pulsed light beam passes through the optical enhanced cavity filled with the gas to be measured. The photoacoustic detector is used to measure the intensity of the light pulse in the optical cavity, and the feedback link is used to amplify and adjust the light source, so as to measure the gas concentration by amplifying the adjusted light source. Secondly, the enhanced cavity is built as a V-shaped cavity, and the system optical path is optimized by the V-shaped cavity. The cavity ring-down time under the vacuum state is measured by the cavity ring-down spectroscopy technology, and then the system enhancement parameters are obtained. The enhanced parameters are used to achieve high-accuracy and high-sensitivity measurement of the gas. However, in the above two solutions, the former requires the addition of an optical modulator, and the latter requires the increase of the number of plane mirrors and concave mirrors, which makes the systems of the above two solutions relatively redundant. Therefore, a solution is urgently needed to achieve the enhancement of infrared light under the premise of simplifying the gas detection system. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a detection method and system for an environmental greenhouse gas monitor based on cavity enhancement, which can realize the enhancement of infrared light while simplifying the gas detection system.

[0005] In a first aspect, the present invention provides a detection method of an ambient greenhouse gas monitor based on cavity enhancement, comprising:

[0006] Identify the gas region where the gas to be detected is located, and determine the instrument composition of the environmental greenhouse gas monitor of the gas to be detected, wherein the instrument composition includes an infrared spectrometer, an integrated detector, a single-frequency infrared laser and an enhancement cavity, and the enhancement cavity includes a transmitting concave mirror and a reflecting concave mirror;

[0007] The infrared sample of the enhancement cavity is constructed by using the single-frequency infrared laser, after the infrared sample is emitted from the single-frequency infrared laser to the enhancement cavity, the number of infrared rays in the reflected sample reflected from the enhancement cavity is calculated in the integrated detector, and the infrared emission angle of the enhancement cavity is detected by using the number of infrared rays;

[0008] Calculating the transmission length of the infrared sample in the enhancement cavity, and constructing a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length, so as to place the instrument component on the gas region through the placement position;

[0009] After placing the instrument assembly on the gas area through the placement position, calculating the sample error between the infrared sample and the reflection sample, adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain an adjusted wavelength, and using the adjusted wavelength to query the gas category of the gas to be detected;

[0010] Setting the integration time and the average number of times of the infrared spectrometer to obtain a set infrared spectrometer, after emitting detection infrared rays from the single-frequency infrared laser to the enhancement cavity according to the adjustment wavelength, using the set infrared spectrometer to detect the spectrum of the reflected infrared rays reflected back from the enhancement cavity, and using the spectrum to calculate the gas concentration of the gas to be detected;

[0011] The gas category and the gas concentration are used as gas detection results of the environmental greenhouse gas monitor.

[0012] In a possible implementation manner of the first aspect, calculating the number of infrared rays in the reflection sample reflected back by the enhancement cavity in the integrated detector includes:

[0013] Acquiring a light spot image on the enhancement cavity using the integrated detector;

[0014] Detecting a light spot area from the light spot image using a preset global threshold segmentation algorithm;

[0015] Selecting the light spot region with the smallest area from the light spot regions;

[0016] Calculate the area average of the minimum spot area;

[0017] Selecting overlapping light spot regions with an area larger than the area average in the light spot regions;

[0018] Calculate the longest distance of pixels in the overlapping spot area;

[0019] Identify the number of distances of the longest distance of the pixel;

[0020] Determining the number of overlapping light spots in the overlapping light spot area by using the number of distances;

[0021] The sum of the number of minimum light spots in the light spot area with the smallest area and the number of overlapping light spots is taken as the number of infrared rays.

[0022] In a possible implementation manner of the first aspect, the detecting the infrared emission angle of the enhancement cavity by using the number of infrared rays includes:

[0023] Selecting the maximum number of infrared rays from the numbers of infrared rays;

[0024] Based on the maximum number of infrared rays, the infrared emission angle of the enhancement cavity is calculated using the following formula:

[0025] ;

[0026] in, represents the infrared emission angle of the enhancement cavity, Indicates the maximum number of infrared rays. represents the radius of the curvature circle formed by the emitting concave mirror and the reflecting concave mirror in the enhancement cavity, Represents the diameter of the enhancement cavity.

[0027] In a possible implementation manner of the first aspect, calculating the transmission length of the infrared sample in the enhancement cavity includes:

[0028] The cavity mirror reflectivity of the infrared sample in the enhancement cavity is calculated using the following formula:

[0029] ;

[0030] in, is the cavity mirror reflectivity, represents the intensity of the infrared sample, represents the intensity of the infrared sample refracted in the enhancement cavity, It indicates the absorption of infrared light by the gas in the enhancement cavity at a certain concentration. represents the distance between the emitting concave mirror and the reflecting concave mirror in the enhancement cavity;

[0031] Based on the reflectivity of the cavity mirror, the transmission length of the infrared sample in the enhanced cavity is calculated using the following formula:

[0032] ;

[0033] in, Indicates the transmission length, is the cavity mirror reflectivity, Represents the distance between the emitting concave mirror and the reflecting concave mirror in the enhancement cavity.

[0034] In a possible implementation of the first aspect, constructing a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length includes:

[0035] The center point on the gas region is calculated using the following formula:

[0036] ;

[0037] in, represents the center point, represents the first coordinate on the boundary of the gas region, represents the second coordinate on the boundary of the gas region, represents the mth coordinate on the boundary of the gas region, and m represents the total number of coordinates on the boundary of the gas region;

[0038] Query the infrared refracted on the emitting concave mirror by the infrared sample at the infrared emitting angle;

[0039] Based on the refracted infrared rays and the transmission length, the vertical length between the emitting concave mirror and the center point is calculated using the following formula:

[0040] ;

[0041] ;

[0042] in, Indicates the vertical length, Indicates half of the transmission length, Indicates the refraction angle corresponding to the refracted infrared rays;

[0043] Based on the refracted infrared rays and the transmission length, the horizontal length between the emitting concave mirror and the center point is calculated using the following formula:

[0044] ;

[0045] ;

[0046] in, represents the horizontal length, Indicates half of the transmission length, Indicates the refraction angle corresponding to the refracted infrared rays;

[0047] Determining a first relative position of the emitting concave mirror relative to the center point according to the vertical length and the horizontal length;

[0048] Determining a second relative position of the reflective concave mirror relative to the center point according to the first relative position;

[0049] Determining a first placement position of the enhancement cavity, the infrared spectrometer, and the integrated detector by using the first relative position and the second relative position;

[0050] Determining a second placement position of the single-frequency infrared laser by using the infrared emission angle;

[0051] The first placement position and the second placement position are used as the placement positions.

[0052] In a possible implementation manner of the first aspect, calculating a sample error between the infrared sample and the reflection sample includes:

[0053] Obtain the linewidth enhancement factor of a single-frequency infrared laser;

[0054] According to the line width enhancement factor of the single-frequency infrared laser, the sample error between the infrared sample and the reflection sample is calculated using the following formula:

[0055] ;

[0056] in, represents the sample error, f represents the frequency of the reflected sample, represents the linewidth enhancement factor of a single-frequency infrared laser, represents the optical power reflected from the sample, represents the speed of light reflected from the sample, Indicates the transmission length, is the cavity mirror reflectivity, represents the one-way transmission time of the reflected sample in the enhancement cavity.

[0057] In a possible implementation manner of the first aspect, adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain the adjusted wavelength includes:

[0058] Inputting the sample error into a preset PID controller;

[0059] In the preset PID controller, the adjustment frequency of the single-frequency infrared laser is calculated according to the sample error using the following formula:

[0060] ;

[0061] in, Indicates the adjustment frequency. represents the proportional gain, represents the integration time constant, represents the differential time constant, express , represents sample error, t represents time;

[0062] The adjustment wavelength of the single-frequency infrared laser is determined according to the adjustment frequency.

[0063] In a possible implementation manner of the first aspect, setting the integration time and the number of averaging times of the infrared spectrometer to obtain a set infrared spectrometer includes:

[0064] Measuring the frequency domain signal of the reflection sample using the infrared spectrometer;

[0065] Convert the frequency domain signal into a time domain signal using a preset inverse Fourier transform;

[0066] Based on the time domain signal, the measurement error of the infrared spectrometer is calculated using the following formula:

[0067] ;

[0068] ;

[0069] in, represents the measurement error, i represents the sequence number of the time period in the time domain signal, represents the total number of time periods in the time domain signal, represents the total duration of the time domain signal, represents the length of the time period in the time domain signal, represents the time domain signal value in the jth time period;

[0070] When the measurement error is minimum, the length of the time period corresponding to the measurement error is used as the integration time;

[0071] When the measurement error is the smallest, the total number of time periods corresponding to the measurement error is taken as the average number of times.

[0072] In a possible implementation manner of the first aspect, calculating the gas concentration of the gas to be detected by using the spectrum graph includes:

[0073] detecting the reflected light intensity of the reflected infrared ray in the spectrum graph, and detecting the detected light intensity of the detected infrared ray;

[0074] According to the reflected light intensity and the detected light intensity, the gas concentration of the gas to be detected is calculated using the following formula:

[0075] ;

[0076] in, Indicates the gas concentration, Indicates the reflected light intensity, represents the detected light intensity, represents the attraction cross section in the enhanced cavity, Indicates the effective length of the interaction between the light source and the gas to be detected.

[0077] In a second aspect, the present invention provides a detection system for a cavity-enhanced ambient greenhouse gas monitor, the system comprising:

[0078] An instrument determination module, used to identify the gas region where the gas to be detected is located, and determine the instrument composition of the environmental greenhouse gas monitor of the gas to be detected, wherein the instrument composition includes an infrared spectrometer, an integrated detector, a single-frequency infrared laser and an enhancement cavity, and the enhancement cavity includes a transmitting concave mirror and a reflecting concave mirror;

[0079] An angle detection module, used to construct an infrared sample of the enhancement cavity using the single-frequency infrared laser, and after emitting the infrared sample from the single-frequency infrared laser to the enhancement cavity, calculate the number of infrared rays in the reflected sample reflected from the enhancement cavity in the integrated detector, and use the number of infrared rays to detect the infrared emission angle of the enhancement cavity;

[0080] An instrument placement module, used for calculating the transmission length of the infrared sample in the enhancement cavity, and constructing a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length, so as to place the instrument component on the gas region through the placement position;

[0081] a category query module, for calculating a sample error between the infrared sample and the reflection sample after placing the instrument assembly on the gas region through the placement position, adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain an adjusted wavelength, and using the adjusted wavelength to query the gas category of the gas to be detected;

[0082] a concentration calculation module, used to set the integration time and the average number of times of the infrared spectrometer, obtain the set infrared spectrometer, and after emitting the detection infrared ray from the single-frequency infrared laser to the enhancement cavity according to the adjustment wavelength, use the set infrared spectrometer to detect the spectrum of the reflected infrared ray reflected from the enhancement cavity, and use the spectrum to calculate the gas concentration of the gas to be detected;

[0083] The result determination module is used to use the gas category and the gas concentration as the gas detection result of the environmental greenhouse gas monitor.

[0084] Compared with the prior art, the technical principle and beneficial effects of this solution are:

[0085] The embodiment of the present invention calculates the number of infrared rays in the reflected sample reflected back from the enhancement cavity in the integrated detector, so as to construct a maximum number of infrared rays for the gas molecules based on the principle of energy leapfrogging due to multiple absorption of light energy by gas molecules, so that the gas analysis can achieve a great energy enhancement after absorbing a large amount of reflected light, thereby increasing the accuracy of measuring trace gases with low energy. The embodiment of the present invention calculates the transmission length of the infrared sample in the enhancement cavity, so as to calculate the distance of the gas passed by the infrared sample after passing through the emitting concave mirror into the enhancement cavity, so that the length of the enhancement cavity can be set later according to the distance passed by the infrared sample. Furthermore, the embodiment of the present invention Based on the infrared emission angle and the transmission length, the placement position of the instrument components on the gas area is constructed so that the infrared rays can pass through the center point of the gas area, and under the action of the emitting concave mirror and the reflecting concave mirror, the infrared rays reflected multiple times pass through the center point and the surrounding area of ​​the center point, thereby realizing the energy enhancement of the gas molecules in the center point and the surrounding area of ​​the center point. The embodiment of the present invention calculates the sample error between the infrared sample and the reflected sample to reduce the sample error in the subsequent process, so that the emitted infrared rays and the infrared rays fed back can resonate, thereby improving the stability of the enhanced cavity. The embodiment of the present invention sets the integration time and average times of the infrared spectrometer to reduce the noise error of the subsequent spectrum. Therefore, the detection method and system of the environmental greenhouse gas monitor based on cavity enhancement proposed in the embodiment of the present invention can realize the enhancement of infrared light under the premise of simplifying the gas detection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0087] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0088] Figure 1 A schematic flow chart of a detection method of a cavity-enhanced ambient greenhouse gas monitor provided by an embodiment of the present invention;

[0089] Figure 2 In one embodiment of the present invention Figure 1 A schematic diagram of the placement of a detection method for a cavity-enhanced ambient greenhouse gas monitor is provided;

[0090] Figure 3 In one embodiment of the present invention Figure 1 A schematic diagram of vertical length and horizontal length of a detection method for a cavity-enhanced ambient greenhouse gas monitor is provided;

[0091] Figure 4 A schematic diagram of a module of a detection system of a cavity-enhanced environmental greenhouse gas monitor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0092] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0093] The embodiment of the present invention provides a detection method for a cavity-enhanced environmental greenhouse gas monitor, and the execution subject of the detection method for a cavity-enhanced environmental greenhouse gas monitor includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided by the embodiment of the present invention. In other words, the detection method for a cavity-enhanced environmental greenhouse gas monitor can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc. The server can be an independent server, or it can be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (Content Delivery Network, CDN), and big data and artificial intelligence platforms.

[0094] See also Figure 1 FIG. 1 is a flow chart of a detection method of a cavity-enhanced ambient greenhouse gas monitor according to an embodiment of the present invention. Figure 1 The detection method described in the cavity-enhanced ambient greenhouse gas monitor includes:

[0095] S1. Identify the gas region where the gas to be detected is located, and determine the instrument composition of the environmental greenhouse gas monitor of the gas to be detected, wherein the instrument composition includes an infrared spectrometer, an integrated detector, a single-frequency infrared laser and an enhancement cavity, and the enhancement cavity includes an emitting concave mirror and a reflecting concave mirror.

[0096] In an embodiment of the present invention, the integrated detector refers to a linear array CCD device and a computer system, the linear array CCD device is used to capture a light spot image, and the computer system is used to analyze the light spot in the light spot image. Furthermore, the single-frequency infrared laser refers to a single longitudinal mode laser, which is characterized in that the output laser mode satisfies both a single transverse mode and a single longitudinal mode, and the infrared laser emitted by it oscillates in only a single longitudinal mode inside the resonant cavity, and the output light intensity presents a Gaussian distribution.

[0097] S2. Utilize the single-frequency infrared laser to construct an infrared sample of the enhancement cavity. After emitting the infrared sample from the single-frequency infrared laser to the enhancement cavity, calculate the number of infrared rays in the reflected sample reflected from the enhancement cavity in the integrated detector, and use the number of infrared rays to detect the infrared emission angle of the enhancement cavity.

[0098] In the embodiment of the present invention, the infrared samples refer to infrared rays at multiple different emission angles but with the same light intensity.

[0099] Furthermore, the embodiment of the present invention calculates the number of infrared rays in the reflected sample reflected back by the enhancement cavity in the integrated detector, so as to realize the principle of energy leapfrogging based on the multiple absorption of light energy by gas molecules, and constructs the maximum number of infrared rays for gas molecules, so that the gas analysis can achieve a great energy enhancement after absorbing a large amount of reflected light, thereby increasing the accuracy of measuring trace gases with low energy.

[0100] The reflection sample includes infrared rays refracted by the infrared sample after passing through the emitting concave mirror and infrared rays reflected by the reflecting concave mirror.

[0101] In one embodiment of the present invention, the number of infrared rays in the reflected sample reflected back by the enhancement cavity is calculated in the integrated detector, including: using the integrated detector to obtain a spot image on the enhancement cavity; using a preset global threshold segmentation algorithm to detect a spot area from the spot image; selecting a spot area with the smallest area from the spot area; calculating the area mean of the spot area with the smallest area; selecting an overlapping spot area with an area greater than the area mean from the spot area; calculating the longest pixel distance of the overlapping spot area; identifying the number of distances of the longest pixel distance; using the number of distances to determine the number of overlapping spots in the overlapping spot area; and taking the sum of the minimum number of spots in the spot area with the smallest area and the number of overlapping spots as the number of infrared rays.

[0102] Among them, the preset global threshold segmentation algorithm is used to segment the spot area and the background area by setting the threshold. Furthermore, the spot area with the smallest area refers to a single spot area, the overlapping spot area refers to an area where multiple spots overlap, and the longest pixel distance refers to the longest distance among the pixel distances on the boundary of the overlapping spot area, which is used to reflect the longest length of the overlapping spot area. When the longest pixel distance is only 1, it indicates that two circular spots overlap, and when the longest pixel distance is only 2, it indicates that three circular spots overlap. It should be noted that the longest pixel distance passes through the center point of the overlapping spot area, that is, the center point of the intersection area of ​​multiple intersecting circles.

[0103] In one embodiment of the present invention, the detecting the infrared emission angle of the enhancement cavity by using the number of infrared rays comprises: selecting the maximum number of infrared rays from the number of infrared rays; and calculating the infrared emission angle of the enhancement cavity based on the maximum number of infrared rays by using the following formula:

[0104] ;

[0105] in, represents the infrared emission angle of the enhancement cavity, Indicates the maximum number of infrared rays. represents the radius of the curvature circle formed by the emitting concave mirror and the reflecting concave mirror in the enhancement cavity, Represents the diameter of the enhancement cavity.

[0106] S3. Calculate the transmission length of the infrared sample in the enhancement cavity, and construct a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length, so as to place the instrument component on the gas region through the placement position.

[0107] The embodiment of the present invention calculates the transmission length of the infrared sample in the enhancement cavity to calculate the distance of the gas passed by the infrared sample after passing through the emitting concave mirror into the enhancement cavity, so that the length of the enhancement cavity can be set later according to the distance passed by the infrared sample.

[0108] The transmission length refers to the transmission distance of the infrared sample light entering the enhancement cavity through the emitting concave mirror.

[0109] In one embodiment of the present invention, the step of calculating the transmission length of the infrared sample in the enhancement cavity comprises: calculating the cavity mirror reflectivity of the infrared sample in the enhancement cavity using the following formula:

[0110] ;

[0111] in, is the cavity mirror reflectivity, represents the intensity of the infrared sample, represents the intensity of the infrared sample refracted in the enhancement cavity, It indicates the absorption of infrared light by the gas in the enhancement cavity at a certain concentration. represents the distance between the emitting concave mirror and the reflecting concave mirror in the enhancement cavity;

[0112] Based on the reflectivity of the cavity mirror, the transmission length of the infrared sample in the enhanced cavity is calculated using the following formula:

[0113] ;

[0114] in, Indicates the transmission length, is the cavity mirror reflectivity, Represents the distance between the emitting concave mirror and the reflecting concave mirror in the enhancement cavity.

[0115] Furthermore, the embodiment of the present invention constructs the placement position of the instrument component on the gas area based on the infrared emission angle and the transmission length, so that the infrared light can pass through the center point of the gas area, and under the action of the emitting concave mirror and the reflecting concave mirror, the infrared light reflected multiple times passes through the center point and the surrounding area of ​​the center point, thereby realizing the energy enhancement of the gas molecules at the center point and the surrounding area of ​​the center point.

[0116] In one embodiment of the present invention, constructing the placement position of the instrument component on the gas area based on the infrared emission angle and the transmission length includes: calculating the center point on the gas area using the following formula:

[0117] ;

[0118] in, represents the center point, represents the first coordinate on the boundary of the gas region, represents the second coordinate on the boundary of the gas region, represents the mth coordinate on the boundary of the gas region, and m represents the total number of coordinates on the boundary of the gas region;

[0119] Query the refracted infrared rays of the infrared sample at the infrared emission angle on the emitting concave mirror; and calculate the vertical length between the emitting concave mirror and the center point based on the refracted infrared rays and the transmission length using the following formula:

[0120] ;

[0121] ;

[0122] in, Indicates the vertical length, Indicates half of the transmission length, Indicates the refraction angle corresponding to the refracted infrared rays;

[0123] Based on the refracted infrared rays and the transmission length, the horizontal length between the emitting concave mirror and the center point is calculated using the following formula:

[0124] ;

[0125] ;

[0126] in, represents the horizontal length, Indicates half of the transmission length, Indicates the refraction angle corresponding to the refracted infrared rays;

[0127] According to the vertical length and the horizontal length, the first relative position of the emitting concave mirror relative to the center point is determined; according to the first relative position, the second relative position of the reflecting concave mirror relative to the center point is determined; the first relative position and the second relative position are used to determine the first placement position of the enhancement cavity, the infrared spectrometer and the integrated detector; the second placement position of the single-frequency infrared laser is determined using the infrared emission angle; the first placement position and the second placement position are used as the placement position.

[0128] See also Figure 2 As shown, an embodiment of the present invention Figure 1 A schematic diagram of the placement of a detection method for a cavity-enhanced ambient greenhouse gas monitor is provided. Figure 2 In the figure, 1 represents a single-frequency infrared laser, 2 represents an emitting concave mirror, 4 represents a gas to be detected, and 3 represents a reflecting concave mirror. It should be noted that the first relative position refers to the position where the detection infrared ray is refracted, and the second relative position refers to a position symmetrical to the first relative position based on the center point. The infrared spectrometer and the integrated detector can be placed near the enhancement cavity and the single-frequency infrared laser, and there is no fixed requirement.

[0129] See also Figure 3 As shown, an embodiment of the present invention Figure 1 A schematic diagram of the vertical length and horizontal length of a detection method for a cavity-enhanced ambient greenhouse gas monitor is provided. Figure 3In the embodiment, the horizontal length refers to the length of the refracted light perpendicular to the normal at the middle position, the vertical length refers to the distance between the point perpendicular to the normal at the middle position of the refracted light and the concave mirror, the length of the refracted light refers to the transmission length, the horizontal line between the first medium and the second medium is the tangent of the concave mirror, the second medium refers to the gas to be detected, the incident light refers to the detection infrared light, the refracted light refers to the reflected infrared light, and the reflected infrared light includes the infrared light refracted by the transmitting concave mirror and the infrared light reflected by the reflecting concave mirror.

[0130] S4. After placing the instrument assembly on the gas area through the placement position, calculate the sample error between the infrared sample and the reflection sample, adjust the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain the adjusted wavelength, and use the adjusted wavelength to query the gas category of the gas to be detected.

[0131] The embodiment of the present invention calculates the sample error between the infrared sample and the reflection sample to reduce the sample error later, so that the emitted infrared light and the fed-back infrared light can achieve resonance, thereby improving the stability of the enhanced cavity.

[0132] In one embodiment of the present invention, the calculating of the sample error between the infrared sample and the reflection sample includes: obtaining a line width enhancement factor of a single-frequency infrared laser; and calculating the sample error between the infrared sample and the reflection sample using the following formula according to the line width enhancement factor of the single-frequency infrared laser:

[0133] ;

[0134] in, represents the sample error, f represents the frequency of the reflected sample, represents the linewidth enhancement factor of a single-frequency infrared laser, represents the optical power reflected from the sample, represents the speed of light reflected from the sample, Indicates the transmission length, is the cavity mirror reflectivity, represents the one-way transmission time of the reflected sample in the enhancement cavity.

[0135] The linewidth enhancement factor refers to an important parameter that affects the output characteristics of a semiconductor laser. The linewidth enhancement factors of semiconductor lasers made of different materials and with different structural types vary greatly, and the linewidth enhancement factor affects the nonlinear single-cycle oscillation characteristics of the semiconductor laser.

[0136] In one embodiment of the present invention, adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain the adjusted wavelength includes: inputting the sample error into a preset PID controller; in the preset PID controller, calculating the adjustment frequency of the single-frequency infrared laser according to the sample error using the following formula:

[0137] ;

[0138] in, Indicates the adjustment frequency. represents the proportional gain, represents the integration time constant, represents the differential time constant, express , represents sample error, t represents time;

[0139] The adjustment wavelength of the single-frequency infrared laser is determined according to the adjustment frequency.

[0140] The preset PID controller is used to control the input variable of the device so that the input variable gradually approaches the standard variable, thereby reducing the error of the input variable.

[0141] Optionally, the process of determining the adjustment wavelength of the single-frequency infrared laser according to the adjustment frequency is to calculate the adjustment wavelength by utilizing the inverse relationship between frequency and wavelength (frequency=speed / wavelength).

[0142] Optionally, the process of using the adjusted wavelength to query the gas category of the gas to be detected is: based on the principle that different types of gases absorb infrared rays of different wavelengths, query the gas that can absorb the infrared rays of the adjusted wavelength and use this gas as the gas category.

[0143] S5. Setting the integration time and the average number of times of the infrared spectrometer to obtain a set infrared spectrometer, after emitting detection infrared light from the single-frequency infrared laser to the enhancement cavity according to the adjusted wavelength, using the set infrared spectrometer to detect a spectrum of the reflected infrared light reflected back from the enhancement cavity, and using the spectrum to calculate the gas concentration of the gas to be detected.

[0144] The embodiment of the present invention sets the integration time and the averaging times of the infrared spectrometer to reduce the noise error of subsequent spectrograms.

[0145] The integration time refers to the exposure time of infrared light irradiating the gas once, and the average number of times refers to the number of times the infrared light irradiates the gas.

[0146] In one embodiment of the present invention, the setting of the integration time and the average number of times of the infrared spectrometer to obtain the set infrared spectrometer includes: measuring the frequency domain signal of the reflection sample by using the infrared spectrometer; converting the frequency domain signal into a time domain signal by using a preset inverse Fourier transform; and calculating the measurement error of the infrared spectrometer based on the time domain signal by using the following formula:

[0147] ;

[0148] ;

[0149] in, represents the measurement error, i represents the sequence number of the time period in the time domain signal, represents the total number of time periods in the time domain signal, represents the total duration of the time domain signal, represents the length of the time period in the time domain signal, represents the time domain signal value in the jth time period;

[0150] When the measurement error is the smallest, the length of the time period corresponding to the measurement error is used as the integration time; when the measurement error is the smallest, the total number of time periods corresponding to the measurement error is used as the average number of times.

[0151] In one embodiment of the present invention, the use of the spectrum to calculate the gas concentration of the gas to be detected includes: detecting the reflected light intensity of the reflected infrared light in the spectrum, and detecting the detection light intensity of the detection infrared light; and calculating the gas concentration of the gas to be detected using the following formula based on the reflected light intensity and the detection light intensity:

[0152] ;

[0153] in, Indicates the gas concentration, Indicates the reflected light intensity, represents the detected light intensity, represents the attraction cross section in the enhanced cavity, Indicates the effective length of the interaction between the light source and the gas to be detected.

[0154] S6. Using the gas category and the gas concentration as the gas detection result of the environmental greenhouse gas monitor.

[0155] It can be seen that the embodiment of the present invention calculates the number of infrared rays in the reflected sample reflected back by the enhancement cavity in the integrated detector, so as to realize the principle of energy leapfrogging based on the multiple absorption of light energy by gas molecules, and construct the maximum number of infrared rays for gas molecules, so that the gas analysis can achieve a great energy enhancement after absorbing a large amount of reflected light, which can increase the accuracy of measuring trace gases with low energy. The embodiment of the present invention calculates the transmission length of the infrared sample in the enhancement cavity, so as to calculate the distance of the gas passed by the infrared sample after passing through the emitting concave mirror into the enhancement cavity, so that the length of the enhancement cavity can be set later according to the distance passed by the infrared sample. Furthermore, the present invention realizes The embodiment constructs the placement position of the instrument components on the gas area based on the infrared emission angle and the transmission length, so that the infrared rays can pass through the center point of the gas area, and under the action of the emitting concave mirror and the reflecting concave mirror, the infrared rays reflected multiple times pass through the center point and the surrounding area of ​​the center point, thereby realizing the energy enhancement of the gas molecules in the center point and the surrounding area of ​​the center point. The embodiment of the present invention calculates the sample error between the infrared sample and the reflected sample to reduce the sample error in the subsequent process, so that the emitted infrared rays and the infrared rays fed back can resonate, thereby improving the stability of the enhanced cavity. The embodiment of the present invention sets the integration time and average times of the infrared spectrometer to reduce the noise error of the subsequent spectrum. Therefore, the detection method of the environmental greenhouse gas monitor based on cavity enhancement proposed in the embodiment of the present invention can realize the enhancement of infrared light under the premise of simplifying the gas detection system.

[0156] like Figure 4 , which is a functional module diagram of the detection system of the cavity-enhanced environmental greenhouse gas monitor of the present invention.

[0157] The detection system 400 of the cavity-enhanced environmental greenhouse gas monitor of the present invention can be installed in an electronic device. According to the functions to be implemented, the detection system of the cavity-enhanced environmental greenhouse gas monitor can include an instrument determination module 401, an angle detection module 402, an instrument placement module 403, a category query module 404, a concentration calculation module 405 and a result determination module 406. The module of the present invention can also be called a unit, which refers to a series of computer program segments that can be executed by an electronic device processor and can complete fixed functions, which are stored in the memory of the electronic device.

[0158] In the embodiment of the present invention, the functions of each module / unit are as follows:

[0159] The instrument determination module 401 is used to identify the gas region where the gas to be detected is located, and determine the instrument composition of the environmental greenhouse gas monitor of the gas to be detected, wherein the instrument composition includes an infrared spectrometer, an integrated detector, a single-frequency infrared laser and an enhancement cavity, and the enhancement cavity includes a transmitting concave mirror and a reflecting concave mirror;

[0160] The angle detection module 402 is used to construct an infrared sample of the enhancement cavity using the single-frequency infrared laser, and after emitting the infrared sample from the single-frequency infrared laser to the enhancement cavity, calculate the number of infrared rays in the reflected sample reflected from the enhancement cavity in the integrated detector, and use the number of infrared rays to detect the infrared emission angle of the enhancement cavity;

[0161] The instrument placement module 403 is used to calculate the transmission length of the infrared sample in the enhancement cavity, and to construct a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length, so as to place the instrument component on the gas region through the placement position;

[0162] The category query module 404 is used to calculate the sample error between the infrared sample and the reflection sample after placing the instrument assembly on the gas area through the placement position, adjust the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain an adjusted wavelength, and use the adjusted wavelength to query the gas category of the gas to be detected;

[0163] The concentration calculation module 405 is used to set the integration time and the average number of times of the infrared spectrometer, obtain the set infrared spectrometer, and after emitting the detection infrared ray from the single-frequency infrared laser to the enhancement cavity according to the adjustment wavelength, use the set infrared spectrometer to detect the spectrum of the reflected infrared ray reflected from the enhancement cavity, and use the spectrum to calculate the gas concentration of the gas to be detected;

[0164] The result determination module 406 is used to use the gas category and the gas concentration as the gas detection result of the environmental greenhouse gas monitor.

[0165] In detail, the modules in the detection system 400 of the chamber-enhanced environmental greenhouse gas monitor according to the embodiment of the present invention are used in the same manner as described above. Figure 1 The detection method of the cavity-enhanced environmental greenhouse gas monitor described in the invention is the same as the technical means and can produce the same technical effects, so it will not be repeated here.

[0166] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0167] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0168] Therefore, no matter from which point of view, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is limited by the appended claims rather than the above description, so it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any attached figure mark in the claims should not be regarded as limiting the claims involved.

[0169] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0170] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features invented herein.

Claims

1. A detection method for an ambient greenhouse gas monitor based on cavity enhancement, characterized in that: The method comprises: Identify the gas region where the gas to be detected is located, and determine the instrument composition of the environmental greenhouse gas monitor of the gas to be detected, wherein the instrument composition includes an infrared spectrometer, an integrated detector, a single-frequency infrared laser and an enhancement cavity, and the enhancement cavity includes a transmitting concave mirror and a reflecting concave mirror; The infrared sample of the enhancement cavity is constructed by using the single-frequency infrared laser, after the infrared sample is emitted from the single-frequency infrared laser to the enhancement cavity, the number of infrared rays in the reflected sample reflected from the enhancement cavity is calculated in the integrated detector, and the infrared emission angle of the enhancement cavity is detected by using the number of infrared rays; Calculating the transmission length of the infrared sample in the enhancement cavity, and constructing a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length, so as to place the instrument component on the gas region through the placement position; After placing the instrument assembly on the gas area through the placement position, calculating the sample error between the infrared sample and the reflection sample, adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain an adjusted wavelength, and using the adjusted wavelength to query the gas category of the gas to be detected; Setting the integration time and the average number of times of the infrared spectrometer to obtain a set infrared spectrometer, after emitting detection infrared rays from the single-frequency infrared laser to the enhancement cavity according to the adjustment wavelength, using the set infrared spectrometer to detect the spectrum of the reflected infrared rays reflected back from the enhancement cavity, and using the spectrum to calculate the gas concentration of the gas to be detected; The gas category and the gas concentration are used as gas detection results of the environmental greenhouse gas monitor.

2. The method according to claim 1, characterized in that Calculating the number of infrared rays in the reflected sample reflected from the enhancement cavity in the integrated detector comprises: Acquiring a light spot image on the enhancement cavity using the integrated detector; Detecting a light spot area from the light spot image using a preset global threshold segmentation algorithm; Selecting the light spot region with the smallest area from the light spot regions; Calculate the area average of the minimum spot area; Selecting overlapping light spot regions with an area larger than the area average in the light spot regions; Calculate the longest distance of pixels in the overlapping spot area; Identify the number of distances of the longest distance of the pixel; Determining the number of overlapping light spots in the overlapping light spot area by using the number of distances; The sum of the number of minimum light spots in the light spot area with the smallest area and the number of overlapping light spots is taken as the number of infrared rays.

3. The method according to claim 1, characterized in that The method of using the number of infrared rays to detect the infrared emission angle of the enhancement cavity comprises: Selecting the maximum number of infrared rays from the numbers of infrared rays; Based on the maximum number of infrared rays, the infrared emission angle of the enhancement cavity is calculated using the following formula: ； in, represents the infrared emission angle of the enhancement cavity, Indicates the maximum number of infrared rays. represents the radius of the curvature circle formed by the emitting concave mirror and the reflecting concave mirror in the enhancement cavity, Represents the diameter of the enhancement cavity.

4. The method according to claim 1, characterized in that: The calculating the transmission length of the infrared sample in the enhancement cavity comprises: The cavity mirror reflectivity of the infrared sample in the enhancement cavity is calculated using the following formula: ； in, is the cavity mirror reflectivity, represents the intensity of the infrared sample, represents the intensity of the infrared sample refracted in the enhancement cavity, It indicates the absorption of infrared light by the gas in the enhancement cavity at a certain concentration. represents the distance between the emitting concave mirror and the reflecting concave mirror in the enhancement cavity; Based on the reflectivity of the cavity mirror, the transmission length of the infrared sample in the enhanced cavity is calculated using the following formula: ； in, Indicates the transmission length, is the cavity mirror reflectivity, Represents the distance between the emitting concave mirror and the reflecting concave mirror in the enhancement cavity.

5. The method according to claim 1, characterized in that The step of constructing a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length includes: The center point on the gas region is calculated using the following formula: ； in, represents the center point, represents the first coordinate on the boundary of the gas region, represents the second coordinate on the boundary of the gas region, represents the mth coordinate on the boundary of the gas region, and m represents the total number of coordinates on the boundary of the gas region; Query the infrared refracted on the emitting concave mirror by the infrared sample at the infrared emitting angle; Based on the refracted infrared rays and the transmission length, the vertical length between the emitting concave mirror and the center point is calculated using the following formula: ； ； in, Indicates the vertical length, Indicates half of the transmission length, Indicates the refraction angle corresponding to the refracted infrared rays; Based on the refracted infrared rays and the transmission length, the horizontal length between the emitting concave mirror and the center point is calculated using the following formula: ； ； in, represents the horizontal length, Indicates half of the transmission length, Indicates the refraction angle corresponding to the refracted infrared rays; Determining a first relative position of the emitting concave mirror relative to the center point according to the vertical length and the horizontal length; Determining a second relative position of the reflective concave mirror relative to the center point according to the first relative position; Determining a first placement position of the enhancement cavity, the infrared spectrometer, and the integrated detector by using the first relative position and the second relative position; Determining a second placement position of the single-frequency infrared laser by using the infrared emission angle; The first placement position and the second placement position are used as the placement positions.

6. The method according to claim 1, characterized in that The calculating the sample error between the infrared sample and the reflection sample comprises: Obtain the linewidth enhancement factor of a single-frequency infrared laser; According to the line width enhancement factor of the single-frequency infrared laser, the sample error between the infrared sample and the reflection sample is calculated using the following formula: ； in, represents the sample error, f represents the frequency of the reflected sample, represents the linewidth enhancement factor of a single-frequency infrared laser, represents the optical power reflected from the sample, represents the speed of light reflected from the sample, Indicates the transmission length, is the cavity mirror reflectivity, represents the one-way transmission time of the reflected sample in the enhancement cavity.

7. The method according to claim 1, characterized in that The step of adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain the adjusted wavelength comprises: Inputting the sample error into a preset PID controller; In the preset PID controller, the adjustment frequency of the single-frequency infrared laser is calculated according to the sample error using the following formula: ； in, Indicates the adjustment frequency. represents the proportional gain, represents the integration time constant, represents the differential time constant, express , represents sample error, t represents time; The adjustment wavelength of the single-frequency infrared laser is determined according to the adjustment frequency.

8. The method according to claim 1, characterized in that The step of setting the integration time and the average number of times of the infrared spectrometer to obtain a set infrared spectrometer includes: Measuring the frequency domain signal of the reflection sample using the infrared spectrometer; Convert the frequency domain signal into a time domain signal using a preset inverse Fourier transform; Based on the time domain signal, the measurement error of the infrared spectrometer is calculated using the following formula: ； ； in, represents the measurement error, i represents the sequence number of the time period in the time domain signal, represents the total number of time periods in the time domain signal, represents the total duration of the time domain signal, represents the length of the time period in the time domain signal, Indicates The time domain signal value within a period; When the measurement error is minimum, the length of the time period corresponding to the measurement error is used as the integration time; When the measurement error is the smallest, the total number of time periods corresponding to the measurement error is taken as the average number of times.

9. The method according to claim 1, characterized in that: The step of calculating the gas concentration of the gas to be detected by using the spectrum graph includes: detecting the reflected light intensity of the reflected infrared ray in the spectrum graph, and detecting the detected light intensity of the detected infrared ray; According to the reflected light intensity and the detected light intensity, the gas concentration of the gas to be detected is calculated using the following formula: ； in, Indicates the gas concentration, Indicates the reflected light intensity, represents the detected light intensity, represents the attraction cross section in the enhanced cavity, Indicates the effective length of the interaction between the light source and the gas to be detected.

10. A detection system for a cavity-enhanced ambient greenhouse gas monitor, characterized in that: The system comprises: An instrument determination module, used to identify the gas region where the gas to be detected is located, and determine the instrument composition of the environmental greenhouse gas monitor of the gas to be detected, wherein the instrument composition includes an infrared spectrometer, an integrated detector, a single-frequency infrared laser and an enhancement cavity, and the enhancement cavity includes a transmitting concave mirror and a reflecting concave mirror; An angle detection module, used to construct an infrared sample of the enhancement cavity using the single-frequency infrared laser, and after emitting the infrared sample from the single-frequency infrared laser to the enhancement cavity, calculate the number of infrared rays in the reflected sample reflected from the enhancement cavity in the integrated detector, and use the number of infrared rays to detect the infrared emission angle of the enhancement cavity; An instrument placement module, used for calculating the transmission length of the infrared sample in the enhancement cavity, and constructing a placement position of the instrument component on the gas region based on the infrared emission angle and the transmission length, so as to place the instrument component on the gas region through the placement position; a category query module, for calculating a sample error between the infrared sample and the reflection sample after placing the instrument assembly on the gas region through the placement position, adjusting the infrared wavelength of the single-frequency infrared laser according to the sample error to obtain an adjusted wavelength, and using the adjusted wavelength to query the gas category of the gas to be detected; a concentration calculation module, used to set the integration time and the average number of times of the infrared spectrometer, obtain the set infrared spectrometer, and after emitting the detection infrared ray from the single-frequency infrared laser to the enhancement cavity according to the adjustment wavelength, use the set infrared spectrometer to detect the spectrum of the reflected infrared ray reflected from the enhancement cavity, and use the spectrum to calculate the gas concentration of the gas to be detected; The result determination module is used to use the gas category and the gas concentration as the gas detection result of the environmental greenhouse gas monitor.

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