Infrared carbon dioxide detection signal processing method, system and sensor

Abstract

The present application relates to the technical field of gas detection, and particularly relates to an infrared carbon dioxide detection signal processing method and system and a sensor, the method comprising: collecting a measurement channel signal and a reference channel signal of a carbon dioxide detection device under a mine environment to form a raw detection signal to be processed; obtaining a distortion discrimination feature representing a response relationship between the measurement channel signal and the reference channel signal according to the raw detection signal; determining whether the raw detection signal is in a normal state that can be used for carbon dioxide concentration calculation based on the distortion discrimination feature; when the raw detection signal is determined to be in the normal state, calculating the carbon dioxide concentration according to the measurement channel signal and the reference channel signal; and when the raw detection signal is determined to not be in the normal state, suppressing a normal concentration output based on the raw detection signal and outputting corresponding distortion state information. Through the present application, the problem of how to avoid misjudging optical distortion as CO2 concentration change under high humidity and high dust conditions in a mine is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and in particular to an infrared carbon dioxide detection signal processing method, system and sensor. Background Technology

[0002] Non-dispersive infrared (NDIR) carbon dioxide detection technology utilizes the absorption characteristics of carbon dioxide in specific infrared bands. It acquires absorption information through a measurement channel and outputs the concentration result after correction using a reference channel and environmental parameters. Existing solutions in mining environments are largely based on this technology, with improvements primarily focused on temperature compensation, humidity compensation, and reference channel compensation. For example, reference document CN113252597B improves the stability of quantitative concentration analysis by combining a mining-grade NDIR structure with temperature compensation; reference document CN114076743B reduces measurement errors caused by temperature changes by using algorithmic compensation for the infrared light intensity signal; and reference document CN212964616U corrects for water vapor interference by setting a humidity compensation channel. The commonality among these existing technologies is that they all assume the current detection signal is still a valid signal for concentration calculation, and compensation is only applied to this basis.

[0003] However, the high humidity, high dust, and easy condensation environment in mines often leads to condensation, dust accumulation, optical path contamination, or changes in scattering during actual testing. In such cases, abnormal signals do not necessarily indicate abnormal carbon dioxide concentrations. Although existing technologies can compensate for factors such as temperature and humidity, they cannot determine whether the current signal has lost its ability to directly represent concentration. Therefore, optical distortion can easily be misinterpreted as a change in actual concentration.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides an infrared carbon dioxide detection signal processing method, system, and sensor, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An infrared carbon dioxide detection signal processing method, the method comprising: The measurement channel signal and reference channel signal of the carbon dioxide detection device in the mine environment are collected to form the raw detection signal to be processed; Based on the original detection signal, obtain distortion discrimination features to characterize the response relationship between the measurement channel signal and the reference channel signal; Based on the distortion discrimination features, it is determined whether the original detection signal is in a normal state that can be used to calculate carbon dioxide concentration; When the original detection signal is determined to be in the normal state, the carbon dioxide concentration is calculated based on the measurement channel signal and the reference channel signal. When the original detection signal is determined to be not in the normal state, the normal concentration output based on the original detection signal is suppressed and the corresponding distortion state information is output.

[0007] Furthermore, the distortion discrimination feature is obtained based on the degree of deviation between the amplitude change of the measured channel signal and the reference channel signal within a preset time period.

[0008] Further, obtaining the distortion discrimination features includes: The degree of deviation is the ratio of the absolute value of the difference between the amplitude change of the measured channel signal and the amplitude change of the reference channel signal to the absolute value of the amplitude change of the reference channel signal. When the deviation is no greater than 0.15, the original detection signal is determined to be in a non-distorted state. When the deviation is greater than 0.15 but not greater than 0.30, the original detection signal is determined to be in a suspected distortion state. When the deviation is greater than 0.30, the original detection signal is determined to be in a distorted state.

[0009] Furthermore, the processing of each discrimination result includes: When the original detection signal is determined to be in the non-distorted state, the carbon dioxide concentration is calculated based on the measurement channel signal and the reference channel signal, and the corresponding concentration result is output. When the original detection signal is determined to be in the suspected distortion state, the output of the current concentration result is temporarily suspended, and the re-acquired measurement channel signal and the reference channel signal are re-evaluated. When the original detection signal is determined to be in the distortion state, the output of the current concentration result is suppressed, and the distortion state information is output.

[0010] Furthermore, if the re-acquired measurement channel signal and the reference channel signal are determined to be in the non-distortion state, the corresponding concentration result is output; if they are still determined to be in the suspected distortion state or the distortion state, a suspected distortion prompt message or the distortion state information is output.

[0011] Furthermore, the corresponding distortion state information is output, including: When the original detection signal is determined to be in a suspected distorted state or a distorted state, the slope of the change of the measurement channel signal and the slope of the change of the reference channel signal during the continuous acquisition process are obtained respectively. Based on the magnitude, direction, and ratio of the slope of the measured channel signal to the slope of the reference channel signal, the type of distortion source corresponding to the suspected distortion state or the distortion state is determined. The distortion status information is generated according to the distortion source type, and the distortion status information is output.

[0012] Furthermore, the type of distortion source is determined based on the relationship between the slopes, including: When the slope of the measurement channel signal changes in the same direction as the slope of the reference channel signal, the slope ratio is close to 1, and the absolute values ​​of both are greater than the rapid change threshold, it is determined to be condensation distortion. When the slope of the measurement channel signal changes in the same direction as the slope of the reference channel signal, the slope ratio is close to 1, and the absolute values ​​of both are not greater than the rapid change threshold, it is determined to be dust accumulation or optical window contamination distortion. When the slope of the measured channel signal changes in the opposite direction to the slope of the reference channel signal, or when the slope ratio deviates from the set ratio range, it is determined to be an abnormal distortion of optical path scattering.

[0013] Furthermore, the rapid change threshold is determined based on the statistical results of the change slopes of the measurement channel signal and the reference channel signal during continuous acquisition when the original detection signal is in a non-distorted state.

[0014] An infrared carbon dioxide detection signal processing system, the system comprising: The signal acquisition module acquires the measurement channel signal and reference channel signal of the carbon dioxide detection device in the mine environment to form the raw detection signal to be processed; The feature acquisition module acquires distortion discrimination features based on the original detection signal to characterize the response relationship between the measurement channel signal and the reference channel signal; The distortion discrimination module determines whether the original detection signal is in a normal state that can be used to calculate carbon dioxide concentration based on the distortion discrimination characteristics. The concentration calculation module calculates the carbon dioxide concentration based on the measurement channel signal and the reference channel signal when the original detection signal is determined to be in a normal state. The status output module, when the original detection signal is determined to be not in a normal state, suppresses the normal concentration output based on the original detection signal and outputs the corresponding distortion status information.

[0015] A sensor includes several hardware units and / or processing units, wherein the processing units are configured to implement the infrared carbon dioxide detection signal processing method when executed.

[0016] The technical solution of this invention can achieve the following technical effects: By improving the traditional dual-channel NDIR detection logic that directly calculates concentration after sampling, to a logic that first determines whether the signal is still eligible for concentration calculation after sampling, and then decides whether to output the concentration, it can effectively avoid the distortion signal caused by factors such as condensation, dust accumulation, window contamination, or abnormal scattering in the mining environment being mistakenly output as a normal concentration signal. This effectively solves the problem of how to avoid misjudging optical distortion as a change in CO2 concentration under high humidity and high dust conditions in mines.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating an infrared carbon dioxide detection signal processing method. Figure 2 This is a schematic diagram of a dual-channel signal; Figure 3 A flowchart illustrating the process of obtaining distortion discrimination features; Figure 4 This is a schematic diagram illustrating the source of distortion in continuous slope analysis. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] Example 1; like Figure 1 As shown, this application provides an infrared carbon dioxide detection signal processing method, the method comprising: S10: Collect the measurement channel signal and reference channel signal of the carbon dioxide detection device in the mine environment to form the raw detection signal to be processed; S20: Obtain distortion discrimination features based on the original detection signal to characterize the response relationship between the measurement channel signal and the reference channel signal; S30: Determine whether the original detection signal is in a normal state that can be used to calculate carbon dioxide concentration based on the distortion discrimination characteristics; S40: When the original detection signal is determined to be in a normal state, calculate the carbon dioxide concentration based on the measurement channel signal and the reference channel signal; S50: When the original detection signal is determined to be in an abnormal state, suppress the normal concentration output based on the original detection signal and output the corresponding distortion state information.

[0023] Specifically, this embodiment is based on the non-dispersive infrared carbon dioxide detection method. The detection device includes a measurement channel and a reference channel. The measurement channel is used to acquire the absorption response of the gas to be tested to the target infrared band, and the reference channel is used to acquire the corresponding reference response. In one embodiment, the measurement channel signal and the reference channel signal are synchronously acquired at the same sampling time and combined to form the original detection signal. In another embodiment, the original detection signal may also include the measurement channel signal sequence and the reference channel signal sequence at multiple consecutive sampling times for subsequent distortion discrimination processing. Furthermore, the distortion discrimination feature is preferably obtained by analyzing the changes in the measurement channel signal and the reference channel signal within a preset time period. Since, under normal operating conditions, the measurement channel signal and the reference channel signal should maintain a relatively stable correspondence when affected by common factors such as light source attenuation, device drift, and changes in overall transmittance, a significant deviation in the response relationship between the measurement channel signal and the reference channel signal indicates that the original detection signal may have been affected by distortion factors such as condensation, dust accumulation, contamination, or abnormal scattering. In one embodiment, the distortion discrimination feature can be composed of the amplitude changes of the measurement channel signal and the reference channel signal, as well as the degree of deviation between them. In this way, the response consistency between the two channel signals can be transformed into a discriminable feature quantity. Furthermore, the normal state refers to the state in which the measurement channel signal and the reference channel signal still maintain a normal optical response relationship. In this state, the changes reflected by the original detection signal can still be regarded as an effective concentration response. Accordingly, when the distortion discrimination feature indicates that the response relationship between the measurement channel signal and the reference channel signal has not been significantly disrupted, the original detection signal is determined to be in a normal state. When the distortion discrimination feature indicates that an abnormal mismatch has occurred between the measurement channel signal and the reference channel signal, the original detection signal is determined to be in a non-normal state.

[0024] Furthermore, when the processor determines that the original detection signal is in a normal state, it means that the response relationship between the current measurement channel signal and the reference channel signal still meets the normal solution conditions. At this time, the carbon dioxide concentration can be calculated according to the existing dual-channel NDIR concentration solution method. Furthermore, when the processor determines that the original detection signal is not in a normal state, the original detection signal may no longer be suitable as input for concentration calculation. In this case, this embodiment no longer outputs the carbon dioxide concentration value according to the normal mode, but suppresses the normal concentration output and outputs distortion status information. The distortion status information is used to characterize whether the current original detection signal has a risk of distortion or is already in a distorted state. In one embodiment, the distortion status information can be an abnormal prompt; in another embodiment, the distortion status information may further include suspected distortion status information, distortion status information, or distortion source prompt information. By outputting distortion status information, the user can be prompted that the current detection result is not suitable for direct use as a normal concentration result, and a basis can be provided for subsequent retesting, maintenance, or further diagnosis.

[0025] The technical solution of this invention improves the traditional dual-channel NDIR detection process, which directly calculates the concentration after sampling, to a process that first determines whether the signal is still eligible for concentration calculation after sampling, and then decides whether to output the concentration. This effectively avoids the distortion signal caused by factors such as condensation, dust accumulation, window contamination, or abnormal scattering in the mining environment from being mistakenly output as a normal concentration signal. It effectively solves the problem of how to avoid misjudging optical distortion as a change in CO2 concentration under high humidity and high dust conditions in mines.

[0026] Furthermore, such as Figure 2 As shown, distortion discrimination features are obtained based on the degree of deviation between the amplitude changes of the measured channel signal and the reference channel signal within a preset time period.

[0027] As a preferred embodiment of the above, the distortion discrimination feature is obtained based on the degree of deviation between the amplitude change of the measured channel signal and the reference channel signal.

[0028] Specifically, because infrared detection signals in a mining environment are easily affected by instantaneous noise, short-term airflow disturbances, and sampling jitter, misjudgments may occur if a single sampling point is used directly for distortion discrimination. Selecting a preset time period as the analysis window is to avoid the influence of random errors caused by judging solely based on instantaneous sampling values. The preset time period can be the time interval corresponding to several consecutive sampling cycles. In each preset time period, the difference between the measurement channel signal value and the reference channel signal value corresponding to the start and end times is determined as the amplitude change of the measurement channel signal and the reference channel signal within that preset time period. The deviation between the measurement channel signal and the reference channel signal is further calculated, and the deviation is used as a distortion discrimination feature, or the deviation, the amplitude change of the measurement channel signal, and the amplitude change of the reference channel signal are used together as distortion discrimination features.

[0029] Figure 2 This is a schematic diagram of the dual-channel infrared carbon dioxide detection signal of the present invention, showing the change of amplitude of the measurement channel signal and the reference channel signal over time during continuous acquisition in a mining environment; like Figure 2 As shown, the horizontal axis represents the acquisition time, and the vertical axis represents the signal amplitude; the red curve represents the measurement channel signal, and the green curve represents the reference channel signal; the measurement channel corresponds to the detection signal in the carbon dioxide absorption band, and the reference channel corresponds to the signal in the non-absorption band or weak absorption band. During the time intervals of 0-19 seconds and 26-47 seconds, the signal amplitudes of the measurement channel and the reference channel remained basically consistent, with only minor fluctuations, indicating that the system was in normal condition and that there was no significant distortion in the dual-channel response relationship. During the period of 20 to 25 seconds, the amplitude of the measurement channel signal increases significantly, while the reference channel signal changes little, resulting in a significant deviation. According to the method in this embodiment, this amplitude deviation is determined to be a distortion state and can be further used to calculate distortion discrimination features, thereby triggering subsequent distortion source determination and concentration output suppression processing.

[0030] Furthermore, such as Figure 3 As shown, the distortion discrimination features are obtained, including: The degree of deviation is the ratio of the absolute value of the difference between the amplitude change of the measured channel signal and the amplitude change of the reference channel signal to the absolute value of the amplitude change of the reference channel signal. When the deviation is no greater than 0.15, the original detection signal is determined to be in a non-distorted state; When the deviation is greater than 0.15 but not greater than 0.30, the original detection signal is judged to be in a suspected distortion state; When the deviation is greater than 0.30, the original detection signal is determined to be in a distorted state.

[0031] As a preferred embodiment of the above, each detection threshold is determined based on the relative change distribution of the target absorption band and the reference band under normal and distorted operating conditions. Specifically, in the sensor calibration stage, dual-channel signals are first acquired under different carbon dioxide concentrations and different temperature and humidity backgrounds in a non-distorted state, and the deviation distribution within each time window is calculated. Since the deviation obtained in this stage mainly comes from the filter passband difference, detector response difference, light source fluctuation, and finite residual caused by environmental disturbance, its upper boundary can be used to characterize the maximum relative mismatch allowed to exist in the dual channels under normal conditions. Furthermore, under simulated slightly distorted conditions, such as initial condensation on the window surface, a small amount of dust adhesion, or local transmittance fluctuations, the dual-channel signals are collected again and the degree of deviation is calculated. At this time, the degree of deviation will be significantly higher than that under normal conditions. Under simulated significantly distorted conditions, such as continuous condensation, stable water film coverage, significant dust pollution, or abnormal scattering paths, the degree of deviation will further increase and form a clear separation from the normal operating condition distribution. Therefore, in this embodiment, 0.15 and 0.30 are not empirical constants, but are determined based on the normalized deviation distribution boundaries of the carbon dioxide absorption band and the reference band under normal, slightly distorted and significantly distorted conditions. Among them, 0.15 corresponds to the upper limit of the distribution under normal operating conditions, and 0.30 corresponds to the lower limit of the distribution under significantly distorted operating conditions.

[0032] Furthermore, the processing of each judgment result includes: When the original detection signal is determined to be in a non-distorted state, the carbon dioxide concentration is calculated based on the measurement channel signal and the reference channel signal, and the corresponding concentration result is output. When the original detection signal is judged to be in a suspected distorted state, the output of the current concentration result is temporarily suspended, and the re-acquired measurement channel signal and reference channel signal are re-evaluated. When the original detection signal is determined to be distorted, the output of the current concentration result is suppressed, and the distortion status information is output.

[0033] As a preferred embodiment of the above, the non-distorted state, suspected distorted state and distorted state obtained based on the degree of deviation correspond to different degrees of destruction of the dual-channel response relationship, so the same output strategy cannot be used; When the original detection signal is determined to be in a non-distorted state, it means that the current dual-channel response relationship has not been significantly damaged by abnormal optical factors. Therefore, the carbon dioxide concentration can be directly calculated and the corresponding concentration result can be output. When the original detection signal is judged to be in a suspected distorted state, it means that the current dual-channel response relationship has deviated from the normal range. However, this deviation may still come from short-term disturbances, transient water vapor adhesion, transient scattering changes or sampling fluctuations. In this case, the signal needs to be detected again before making a judgment. When the original detection signal is determined to be distorted, it indicates that the deviation between the measurement channel signal and the reference channel signal has reached a significant mismatch level. The current dual-channel coupling relationship can no longer reflect the normal concentration calculation conditions. Therefore, the output of the current concentration result is suppressed, and the distortion status information is output.

[0034] Furthermore, if the re-acquired measurement channel signal and reference channel signal are determined to be in a non-distorted state, the corresponding concentration result is output; if they are still determined to be in a suspected distorted state or a distorted state, a suspected distorted state prompt message or a distorted state message is output.

[0035] As a preferred embodiment of the above, if the current anomaly is only a short-term disturbance, the dual-channel response relationship can be restored to the normal range after re-acquisition; if the anomaly persists after re-acquisition, it indicates that the current distortion is persistent and should be further processed as a suspected distortion or distortion state.

[0036] Furthermore, the corresponding distortion state information is output, including: When the original detection signal is determined to be in a suspected distorted state or a distorted state, the slope of the change of the measurement channel signal and the slope of the change of the reference channel signal during the continuous acquisition process are obtained respectively. Based on the relationship between the slope of the measured channel signal and the slope of the reference channel signal, the direction of change, and the ratio of the slopes, the type of distortion source corresponding to the suspected distortion state or the distortion state can be determined. Generate and output the corresponding distortion status information based on the distortion source type.

[0037] As a preferred embodiment of the above, different distortion factors affect the transmission characteristics of the corresponding bands of the measurement channel and the reference channel in different ways, and thus will show different channel change rate relationships in continuous time. Specifically, while condensation, water film adhesion, dust deposition, window contamination, and abnormal light path scattering can all cause the dual-channel response relationship to deviate from the normal state, they do not act on the measurement channel and the reference channel in the same way. When condensation forms, the water film usually covers the optical surface in a short time, causing the transmitted light intensity of the corresponding bands in both channels to decrease rapidly at the same time. Therefore, the slope of change in the measurement channel and the reference channel during continuous acquisition is usually in the same direction, and the absolute value of the slope is relatively large. The formation process of dust deposition or window contamination is relatively slow, and its impact on the two channels is closer to continuous synchronous attenuation. Therefore, the slope of change in the two channels is also usually in the same direction, but its absolute value is relatively small. On the other hand, abnormal light path scattering often manifests as a change in the light energy distribution path or local scattering enhancement. Its effects do not necessarily occur synchronously in the two channels, thus making it easier for the slope of change in the two channels to be inconsistent, or even if the directions are consistent, their slope ratio will deviate significantly from the normal matching range. Based on the above mechanism, this embodiment no longer uses the amplitude difference at a single moment as the basis for identifying the source of distortion, but introduces the slope of change during continuous acquisition; the slope of change is used to characterize the speed and direction of change of the corresponding channel signal in time, thereby reflecting the influence of different distortion factors on the dynamic response relationship of the dual channels.

[0038] Furthermore, such as Figure 4 As shown, the type of distortion source is determined based on the relationship between slopes, including: When the slope of the measured channel signal changes in the same direction as the slope of the reference channel signal, the slope ratio is close to 1, and the absolute values ​​of both are greater than the rapid change threshold, it is determined to be condensation distortion. When the slope of the measurement channel signal changes in the same direction as the slope of the reference channel signal, the slope ratio is close to 1, and the absolute values ​​of both are not greater than the rapid change threshold, it is determined to be dust accumulation or optical window contamination distortion. When the slope of the measured channel signal changes in the opposite direction to the slope of the reference channel signal, or when the slope ratio deviates from the set ratio range, it is determined to be an abnormal distortion of optical path scattering.

[0039] As a preferred embodiment of the above, the rapid change threshold is used to characterize the upper limit of the slope of change of the measurement channel signal and the reference channel signal caused by normal slowly changing factors during continuous acquisition. That is, it is used to distinguish whether the synchronous change of the two channels belongs to a rapid distortion process or a slow distortion process. In other words, the rapid change threshold is not used to determine whether there is distortion, but to further distinguish whether the distortion is a short-term rapid distortion or a long-term slow accumulation distortion, given that distortion has already been determined to exist. The slope ratio deviating from the set ratio range can be judged by ±10%. The underlying principle is that different sources of distortion have different time characteristics affecting the optical system: condensation is usually a sudden process that occurs within a short time. When water vapor reaches the condensation conditions on the window surface, it forms a water film in a short time, causing the transmitted light intensity of the corresponding bands in the measurement and reference channels to decrease rapidly at the same time. Therefore, the absolute value of the slope of the dual-channel change is relatively large. On the other hand, dust deposition or window contamination is usually a gradual process. Its formation depends on particle adhesion, pollution accumulation, or a slow increase in surface deposits, causing the transmitted light intensity of the dual channels to gradually decrease during continuous acquisition. Therefore, the absolute value of the slope of the dual-channel change is relatively small. In other words, although condensation distortion and dust or window contamination distortion may both show changes in the same direction in the dual channels and have similar slope ratios, their rates of change on the time scale are different. The former is a rapid change, while the latter is a slow change. Based on this difference, this embodiment introduces a rapid change threshold as a time response boundary to distinguish between the two types of distortion sources.

[0040] like Figure 4 As shown, the horizontal axis represents the acquisition time, and the vertical axis represents the slope of the signal change. The blue curve represents the slope change of the measurement channel, and the red curve represents the slope change of the reference channel. In the figure, the time range of 0 to 9 seconds is the normal state segment. The slopes of both the measurement channel and the reference channel remain in the range of slow and gradual change, reflecting the stable response of the system under non-distortion conditions. The period from 10 to 19 seconds is a rapid change segment, during which the slopes of the measurement channel and the reference channel are in the same direction and have large absolute values, corresponding to the condensation distortion state in this embodiment; the slope rises rapidly in this segment, indicating that a short-term water film adheres to the surface of the optical window, causing both channels to drop rapidly at the same time; The 20-29 second time interval is a slow change segment. The slopes of the measurement channel and the reference channel are in the same direction but the absolute values ​​are small, which corresponds to the distortion state caused by dust accumulation or optical window contamination. The slope changes slowly in this segment, reflecting the gradual accumulation of contamination that causes the dual-channel response to deviate from the normal state. The time interval from 30 to 39 seconds is the reverse change segment, where the slope of the measured channel is opposite to that of the reference channel, corresponding to an abnormal distortion state of optical path scattering; the reverse change of the slope in this segment indicates that the optical scattering path is abnormal, causing the dual-channel response to be out of sync. The recovery period is from 40 to 49 seconds, during which the slope returns to the low-speed synchronous change range, and the system returns to a non-distorted state.

[0041] Figure 4 By comparing the magnitude, direction, and ratio of the slope of change in the measurement channel and the reference channel over a continuous time period, the determination of different distortion sources can be achieved. In this embodiment, the condensation distortion and slow accumulation distortion are further distinguished by rapidly changing thresholds, so as to achieve accurate identification of the source of distortion in infrared carbon dioxide detection signals in a mining environment.

[0042] Furthermore, the rapid change threshold is determined based on the statistical results of the slope of change of the measurement channel signal and the reference channel signal during continuous acquisition when the original detection signal is in a non-distorted state.

[0043] As a preferred embodiment of the above, the rapid change threshold is a statistical result because the change slope obtained from a single acquisition is easily affected by instantaneous noise, sampling fluctuations and short-term environmental disturbances, and cannot stably characterize the true change rate range of the dual-channel signal under normal conditions. Therefore, it is necessary to acquire the change slope of the measurement channel signal and the reference channel signal multiple times during the continuous acquisition process when the original detection signal is in a non-distorted state, and determine the rapid change threshold based on the overall distribution of the obtained slope data. In one embodiment, under non-distortion conditions, the slopes of the measurement channel signal and the reference channel signal are collected over several time periods, and the mean, standard deviation, or 95th percentile is statistically obtained. A rapidly changing threshold is also considered. It can be defined as: ; in, The average slope under undistorted conditions; The standard deviation of the slope under undistorted conditions; For safety, the setting can be adjusted based on noise levels or environmental fluctuations; Furthermore, the average slope in the undistorted state Defined as: ; Definition of slope standard deviation in undistorted state for: ; in, The average slope of the two channels is defined as follows: ; To measure the channel in a non-distorted state, the first The slope of a continuous sampling time period; For the reference channel in the undistorted state, the first The slope of a consecutive sampling time period; This represents the total number of sampling time periods.

[0044] Example 2; Based on the same inventive concept as the infrared carbon dioxide detection signal processing method in the foregoing embodiments, the present invention also provides an infrared carbon dioxide detection signal processing system, the system comprising: The signal acquisition module acquires the measurement channel signal and reference channel signal of the carbon dioxide detection device in the mine environment to form the raw detection signal to be processed; The feature acquisition module acquires distortion discrimination features based on the original detection signal to characterize the response relationship between the measurement channel signal and the reference channel signal; The distortion discrimination module determines whether the original detection signal is in a normal state that can be used to calculate carbon dioxide concentration based on the distortion discrimination characteristics. The concentration calculation module calculates the carbon dioxide concentration based on the measurement channel signal and the reference channel signal when the original detection signal is determined to be in a normal state. The status output module, when the original detection signal is determined to be not in a normal state, suppresses the normal concentration output based on the original detection signal and outputs the corresponding distortion status information.

[0045] The system described above in this invention can effectively implement an infrared carbon dioxide detection signal processing method, and the technical effects it can achieve are as described in the above embodiments, which will not be repeated here.

[0046] Example 3; Based on the same inventive concept as the infrared carbon dioxide detection signal processing method in the foregoing embodiments, the present invention also provides a sensor including several hardware units and / or processing units, wherein the processing units are configured to implement the infrared carbon dioxide detection signal processing method when executed.

[0047] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for processing infrared carbon dioxide detection signals, characterized in that, The method includes: The measurement channel signal and reference channel signal of the carbon dioxide detection device in the mine environment are collected to form the raw detection signal to be processed; Based on the original detection signal, obtain distortion discrimination features to characterize the response relationship between the measurement channel signal and the reference channel signal; Based on the distortion discrimination features, it is determined whether the original detection signal is in a normal state that can be used to calculate carbon dioxide concentration; When the original detection signal is determined to be in the normal state, the carbon dioxide concentration is calculated based on the measurement channel signal and the reference channel signal. When the original detection signal is determined to be not in the normal state, the normal concentration output based on the original detection signal is suppressed and the corresponding distortion state information is output. Output the corresponding distortion status information, including: When the original detection signal is determined to be in a suspected distorted state or a distorted state, the slope of the change of the measurement channel signal and the slope of the change of the reference channel signal during the continuous acquisition process are obtained respectively. Based on the magnitude, direction, and ratio of the slope of the measured channel signal to the slope of the reference channel signal, the type of distortion source corresponding to the suspected distortion state or the distortion state is determined. Generate the corresponding distortion status information according to the distortion source type, and output the distortion status information; The type of distortion source can be determined based on the relationship between the slopes, including: When the slope of the measurement channel signal changes in the same direction as the slope of the reference channel signal, the slope ratio is close to 1, and the absolute values ​​of both are greater than the rapid change threshold, it is determined to be condensation distortion. When the slope of the measurement channel signal changes in the same direction as the slope of the reference channel signal, the slope ratio is close to 1, and the absolute values ​​of both are not greater than the rapid change threshold, it is determined to be dust accumulation or optical window contamination distortion. When the slope of the measured channel signal changes in the opposite direction to the slope of the reference channel signal, or when the slope ratio deviates from the set ratio range, it is determined to be an abnormal distortion of optical path scattering.

2. The infrared carbon dioxide detection signal processing method according to claim 1, characterized in that, The distortion discrimination feature is obtained based on the degree of deviation between the amplitude change of the measured channel signal and the reference channel signal within a preset time period.

3. The infrared carbon dioxide detection signal processing method according to claim 2, characterized in that, Obtaining the distortion discrimination features includes: The degree of deviation is the ratio of the absolute value of the difference between the amplitude change of the measured channel signal and the amplitude change of the reference channel signal to the absolute value of the amplitude change of the reference channel signal. When the deviation is no greater than 0.15, the original detection signal is determined to be in a non-distorted state; When the deviation is greater than 0.15 but not greater than 0.30, the original detection signal is determined to be in a suspected distortion state. When the deviation is greater than 0.30, the original detection signal is determined to be in a distorted state.

4. The infrared carbon dioxide detection signal processing method according to claim 3, characterized in that, The processing of each discrimination result includes: When the original detection signal is determined to be in the non-distorted state, the carbon dioxide concentration is calculated based on the measurement channel signal and the reference channel signal, and the corresponding concentration result is output. When the original detection signal is determined to be in the suspected distortion state, the output of the current concentration result is temporarily suspended, and the re-acquired measurement channel signal and the reference channel signal are re-evaluated. When the original detection signal is determined to be in the distortion state, the output of the current concentration result is suppressed, and the distortion state information is output.

5. The infrared carbon dioxide detection signal processing method according to claim 4, characterized in that, If the re-acquired measurement channel signal and the reference channel signal are determined to be in the non-distortion state, the corresponding concentration result is output; if they are still determined to be in the suspected distortion state or the distortion state, a suspected distortion prompt message or the distortion state information is output.

6. The infrared carbon dioxide detection signal processing method according to claim 1, characterized in that, The rapid change threshold is determined based on the statistical results of the change slope of the measurement channel signal and the reference channel signal during continuous acquisition when the original detection signal is in a non-distorted state.

7. An infrared carbon dioxide detection signal processing system, characterized in that, The system employing the infrared carbon dioxide detection signal processing method as described in claim 1, comprises: The signal acquisition module acquires the measurement channel signal and reference channel signal of the carbon dioxide detection device in the mine environment to form the raw detection signal to be processed; The feature acquisition module acquires distortion discrimination features based on the original detection signal to characterize the response relationship between the measurement channel signal and the reference channel signal; The distortion discrimination module determines whether the original detection signal is in a normal state that can be used to calculate carbon dioxide concentration based on the distortion discrimination characteristics. The concentration calculation module calculates the carbon dioxide concentration based on the measurement channel signal and the reference channel signal when the original detection signal is determined to be in a normal state. The status output module, when the original detection signal is determined to be not in a normal state, suppresses the normal concentration output based on the original detection signal and outputs the corresponding distortion status information.

8. A sensor, characterized in that, It includes several hardware units and / or processing units, wherein the processing units are configured to implement the infrared carbon dioxide detection signal processing method as described in any one of claims 1-6 when executed.

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