WO2020156107A1 - 一种降低激光气体遥测仪数据误报率的方法和系统 - Google Patents

一种降低激光气体遥测仪数据误报率的方法和系统 Download PDF

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WO2020156107A1
WO2020156107A1 PCT/CN2020/071612 CN2020071612W WO2020156107A1 WO 2020156107 A1 WO2020156107 A1 WO 2020156107A1 CN 2020071612 W CN2020071612 W CN 2020071612W WO 2020156107 A1 WO2020156107 A1 WO 2020156107A1
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echo signal
similarity
waveform
spectrum waveform
signal spectrum
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PCT/CN2020/071612
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English (en)
French (fr)
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陶俊
向少卿
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上海禾赛光电科技有限公司
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Publication of WO2020156107A1 publication Critical patent/WO2020156107A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers

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  • the present invention relates to the technical field of laser telemetry, in particular to a method and system for reducing the false alarm rate of laser gas telemeter data.
  • the laser gas telemeter is a kind of equipment that uses laser as the main method to realize remote sensing detection at a long distance.
  • Laser gas telemeters are often used to determine atmospheric pollution, such as the concentration of pollutants.
  • Gas concentration measurement by reflected echo is a common method of gas telemetry.
  • the light emitted by the light source is collimated and irradiated to the area to be measured.
  • the reflected echo generated after the beam is reflected returns to the photodetector of the telemetry device.
  • the target gas can be calculated by measuring the absorption of the reflected echo by the target gas on the path.
  • the concentration value The laser gas telemeter does not require on-site sampling and can detect the concentration of pollutants in the field in real time.
  • the laser methane telemeter can detect the methane concentration on-site, determine whether there is a natural gas leak or determine the location of the leak source.
  • the laser gas telemeter also has the advantages of high speed, high sensitivity and high safety.
  • the laser gas telemeter will be affected by changes in the detection environment, saturation of the detector, or circuit switching, which may cause data false alarms.
  • the echo signal obtained by the laser gas telemeter will often be distorted. This distortion will cause the measurement result to be wrong and signal false alarms.
  • the purpose of the present invention is to provide a method and system that can prevent the laser gas telemeter from being affected by changes in environmental conditions and reduce the rate of false alarms of the laser gas telemeter.
  • the present invention provides a method for reducing the false alarm rate of laser gas telemeter data, including:
  • a credible echo signal is extracted and used for the detection result calculation.
  • the present invention provides a system for reducing the false alarm rate of laser gas telemeter data, including:
  • the data acquisition unit is configured to obtain the standard signal spectrum waveform and the echo signal spectrum waveform
  • a signal processing unit configured to calculate the similarity between the spectral waveform of the echo signal and the spectral waveform of the standard signal
  • a judgment unit configured to judge whether the echo signal is credible based on the similarity and generate a judgment result
  • the extraction unit is configured to extract a credible echo signal based on the judgment result and use it for the detection result calculation.
  • the detection result includes data such as gas concentration.
  • the present invention provides a laser gas telemeter device, including: a laser, a controller, a memory, and a processor.
  • the memory stores at least one instruction, at least a program, code set or instruction set, and the at least One instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to implement the method for reducing the false alarm rate of laser gas telemeter data.
  • the method and system for reducing the false alarm rate of laser gas telemeter data according to the present invention has the following beneficial effects:
  • the echo signal spectrum waveform and the standard signal spectrum waveform are compared for similarity, the echo signal is judged based on the similarity value, and the credible echo signal is used to calculate the detection result.
  • the technical solution provided by the present invention can improve the accuracy of detection results, avoid signal distortion caused by signal saturation, circuit switching and/or drastic changes in environmental conditions, and effectively reduce the data false alarm rate of the laser gas telemeter.
  • Fig. 1 is a schematic structural diagram of a laser gas telemeter device provided by an embodiment of the present invention
  • Fig. 2 is a schematic flowchart of a method for reducing the false alarm rate of laser gas telemeter data provided by an embodiment of the present invention
  • Figure 3 A set of standard signal spectral waveforms provided by the embodiment of the present invention (Figure a) and echo signal spectral waveforms obtained under strong light interference from the surrounding environment ( Figure b-i);
  • FIG. 4 is a schematic diagram of the division of characteristic regions of a standard signal spectral waveform provided by an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of the division of characteristic regions of another standard signal spectrum waveform according to an embodiment of the present invention.
  • Figure 6 Another set of echo signal spectrum waveforms provided by the embodiment of the present invention ( Figures a-d);
  • FIG. 7 is a schematic structural diagram of a system for reducing the false alarm rate of laser gas telemeter data provided by an embodiment of the present invention.
  • Figure 1 is a schematic structural diagram of a laser gas telemeter device provided by an embodiment of the present invention.
  • the device may include a laser, a signal detector, a display, a controller, a memory, and a processor. Wait. It may also include a communication device.
  • the processor may include a spectrum analyzer and a signal detection processor.
  • the equipment can be equipped with ranging devices and gas sensor devices.
  • the above device can be a device that can be used alone, such as a handheld laser methane telemeter, etc., or it can be a device that can be integrated into other devices, such as a vehicle, drone, or ship. Laser methane telemeter, etc.
  • the laser in the above-mentioned equipment may be a tunable diode laser, and the above-mentioned equipment may be based on tunable diode laser absorption spectroscopy (TDLAS) technology for gas concentration detection.
  • TDLAS tunable diode laser absorption spectroscopy
  • FIG. 2 is a schematic flowchart of a method for reducing the data false alarm rate of laser gas telemeter according to an embodiment of the present invention.
  • This specification provides method operation steps as described in the embodiments or flowcharts, but conventional or uninvented labor may include more or fewer operation steps.
  • the sequence of steps listed in the embodiment is only one way of the execution order of the steps, and does not represent the only execution order.
  • the method may include:
  • the equipment or system used to implement the method in this specification may be pre-stored with a standard signal spectrum waveform, and the standard signal spectrum waveform may be a test result obtained under standard experimental conditions.
  • the standard signal spectrum waveform may be a test result obtained under standard experimental conditions.
  • an environment that meets the standard conditions is selected at the inspection site, and the obtained echo signal spectrum waveform is used as the standard signal spectrum waveform.
  • select an environmental range where there is no gas to be measured select an environmental range where there is no gas to be measured, and use a standard reflective surface to obtain the echo signal spectrum waveform, which is used as the standard signal spectrum waveform.
  • the standard signal spectrum waveform is pre-stored, more than one standard signal spectrum waveform can be pre-stored. For example, the standard signal spectrum waveform obtained under indoor no light conditions and the standard signal spectrum waveform obtained under urban outdoor air conditions can be stored. Wait.
  • the echo signal spectrum waveform is the echo signal generated by the laser being absorbed by the gas to be measured in the environment and reflected by the reflecting surface.
  • the echo signal is sampled to obtain the echo signal spectrum waveform.
  • the present invention The waveform and period of the laser drive current obtained from the echo signal spectrum waveform obtained in the standard signal spectrum waveform are the same.
  • the echo signal spectral waveform may be affected by environmental factors at the detection site to cause distortion, including but not limited to severe changes in ambient light and/or sharp changes in received reflected light.
  • environmental factors at the detection site including but not limited to severe changes in ambient light and/or sharp changes in received reflected light.
  • the reflection surface of the detection site has different reflectivity or the reflection surface and the laser beam have different reflection angles.
  • Figure 3 is an embodiment of the present invention provides a set of standard signal spectrum waveforms (Figure a) and the echo signal spectrum waveform obtained under the interference of strong ambient light (using a heater to simulate a strong light source) (Figure bi), please refer to Figure 3 Compared with the standard signal spectrum waveform ( Figure a), the echo signal spectrum waveform ( Figure bi) has obvious distortion, and the similarity with the standard signal spectrum waveform is very poor.
  • the similarity calculation formula used is: Wherein, x is the ordinate value of a sampling point in the standard signal spectrum waveform, y is the ordinate value of the same sampling point in the echo signal spectrum waveform, and x 0 is all or all of the standard signal spectrum waveform The average value of the ordinates of all sampling points in a certain area, y 0 is the average value of all the ordinates of the echo signal spectrum waveform corresponding to the standard signal spectrum waveform or all sampling points in a certain area, r xy is The similarity between the echo signal spectral waveform and the standard signal spectral waveform
  • the similarity threshold After obtaining the similarity between the echo signal spectrum waveform and the standard signal spectrum waveform, it is determined whether the similarity is lower than the similarity threshold; if so, it is determined that the echo signal is not credible, and the echo signal is discarded. Echo signal; if not, it is determined that the echo signal is credible.
  • the similarity between the echo signal spectrum waveform obtained in FIG. 3 under the interference of the surrounding environment and the standard spectrum waveform is obtained, and the spectrum corresponding to the graph bi is determined to be the distortion spectrum, that is, the graph bi corresponds to The echo signal of is not credible.
  • S500 Extract a credible echo signal based on the judgment result and use it for detection result calculation.
  • it may be set to extract echo signals whose similarity value is greater than or equal to the similarity threshold to calculate the detection result.
  • the spectral waveform of the echo signal received during each detection and the standard spectral waveform are correlated to obtain a series of similarity results.
  • the credible can be distinguished And unreliable echo signals.
  • unreliable echo signals are discarded, and credible echo signals are selected to calculate the detection result (the detection result includes data such as gas concentration), which improves the accuracy of the test. It can avoid signal distortion or distortion caused by signal saturation, circuit switching, and drastic changes in environmental conditions (such as light), and effectively reduce the rate of data false alarms.
  • the range of the similarity threshold is preferably 0.85-0.95.
  • step S300 may specifically include:
  • the characteristic region is the range of sampling points in the standard signal spectrum waveform that does not include the absorption of the gas to be measured and the environmental interference gas.
  • the characteristic area is the range of sampling points where the absorption of methane and environmental interference gases (such as water vapor, CO 2 etc.) is not included in the standard signal spectrum waveform.
  • the drive current is related to the laser output wavelength and light intensity (the standard signal spectrum waveform is obtained under a given drive current condition, and its sampling point is related to the wavelength), while methane and environmental interference gases (such as water vapor, CO2)
  • the absorption wavelength of etc. is known, and the sampling point range that does not include the absorption of methane and environmental interference gases (such as water vapor, CO2, etc.) is selected as the characteristic area.
  • the characteristic area range may include multiple areas, and the area range may be scattered or continuous.
  • S320 Calculate the similarity between the spectral waveform of the echo signal and the spectral waveform of the standard signal in the characteristic region.
  • x and y refer to the same meaning as above, and x 0 is the average value of the ordinates of all sampling points in the characteristic region of the standard signal spectrum waveform , Y 0 is the average value of the ordinate of all sampling points in the characteristic area of the echo signal spectrum waveform.
  • the step S310 may specifically include:
  • the boundary point of the characteristic area close to the absorption peak of the gas to be measured is the first boundary point
  • the boundary point of the characteristic area away from the absorption peak of the gas to be measured is the second boundary point.
  • the distance between the first boundary point and the reference point is set with reference to the full width of the absorption spectrum of the gas to be measured, and the second boundary point is set according to actual calculations.
  • S312 Determine the characteristic area according to the boundary point
  • the range between the first boundary point and the second boundary point is the characteristic area.
  • n is a positive integer greater than or equal to 1.
  • the characteristic area is determined and the sampling points are preliminarily screened, which reduces the total number of sampling points used for correlation calculations, thereby reducing the amount of calculations for correlation calculations, greatly shortening calculation time, saving time and cost, and reducing hardware requirements.
  • the part enclosed by the two boxes in FIG. 4 is the characteristic area determined on the standard signal spectrum waveform.
  • the reference point corresponding to the absorption peak of the gas to be measured is S
  • the standard signal spectrum waveform includes two characteristic regions in one current driving period
  • the ordinate of the standard signal spectrum waveform represents light intensity.
  • the first characteristic area, the corresponding sampling point is 0-300, that is, the sampling point corresponding to the first boundary point A is 0, and the sampling point corresponding to the second boundary point B is 300.
  • the overall light intensity of this area is weak; the second characteristic area , The corresponding sampling point is 1300-1800, that is, the sampling point corresponding to the third boundary point C is 1300, and the sampling point corresponding to the fourth boundary point D is 1800, and the overall light intensity of the area is strong.
  • the first characteristic area and the second characteristic area are used as characteristic areas.
  • the sampling points in the feature area are used as sampling points for calculating similarity.
  • the sampling point is 0-300 and the sampling point is 1300-1800.
  • x is the ordinate (light intensity) value of a sampling point in the standard signal spectrum waveform
  • y is the ordinate (light intensity) of the same sampling point in the echo signal spectrum waveform and the standard signal spectrum waveform.
  • Strong) value x 0 is the average value of the ordinate (light intensity) of 800 sampling points in the characteristic area in the standard signal spectrum waveform
  • y 0 is the ordinate of the 800 sampling points in the characteristic area in the echo signal spectrum waveform average value.
  • the part enclosed by the two boxes in FIG. 5 is the characteristic area determined on the standard signal spectrum waveform, specifically, the first reference point corresponding to the absorption peak of the gas to be measured Is S 1 and the second reference point is S 2 .
  • the sampling points corresponding to the first boundary point A', the second boundary point B', the third boundary point C', and the fourth boundary point D' are 500, 700, 1000, and 1300, respectively, which are the sampling points corresponding to the first feature area
  • the range is 500-700, and the overall light intensity is relatively strong
  • the sampling point range corresponding to the second feature area is 1000-3000, and the overall light intensity is relatively weak.
  • the sampling points in the first characteristic area and the second characteristic area are used as the sampling points for calculating the similarity.
  • the characteristic area may include areas where the light intensity on the spectral waveform changes drastically, for example, including curve bending points or curve inflection points.
  • the similarity threshold is 0.9.
  • the similarity between the echo signal spectrum waveform in Fig. ad and the standard signal spectrum waveform in Fig. 4 is: 0.999 , 0.985, 0.8 and 0.7. Therefore, it is determined that the echo signals corresponding to the graphs a and b are credible and used for the calculation of the detection result; the echo signals corresponding to the graphs c and d are not credible and are discarded.
  • FIG. 7 is a schematic structural diagram of a system for reducing the false alarm rate of laser gas telemeter data provided by an embodiment of the present invention. 7.
  • the system may include:
  • the data acquisition unit 10 is configured to obtain the standard signal spectrum waveform and the echo signal spectrum waveform
  • the signal processing unit 20 is configured to calculate the similarity between the echo signal spectrum waveform and the standard signal spectrum waveform
  • the judging unit 30 is configured to judge whether the echo signal is credible based on the similarity and generate a judgment result
  • the extraction unit 40 is configured to extract a credible echo signal based on the judgment result and use it for the detection result calculation.
  • the signal processing unit 20 may include:
  • the analysis module may be configured to determine the characteristic area according to the standard signal spectrum waveform
  • the algorithm module may be configured to calculate the similarity between the echo signal spectral waveform and the standard signal spectral waveform in the characteristic region.
  • the algorithm module may be configured to calculate the formula Calculating the similarity
  • x is the ordinate value of a sampling point in the standard signal spectrum waveform
  • y is the ordinate value of the same sampling point in the echo signal spectrum waveform as in the standard signal spectrum waveform
  • x 0 is the The average value of the ordinates of all sampling points in the characteristic area of the standard signal spectrum waveform
  • y 0 is the average value of the ordinates of all sampling points in the characteristic area of the echo signal spectrum waveform.
  • the analysis module may also be configured to:
  • the sampling point range that does not include the absorption of the gas to be measured and the environmental interference gas on the standard signal spectrum waveform is a characteristic area, and there are n characteristic areas, where n is a positive integer greater than or equal to 1. Further, in some embodiments, the determining unit 30 may be configured to determine whether the similarity is lower than a similarity threshold;
  • the echo signal spectrum waveform and the standard signal spectrum waveform are compared for similarity, and the similarity value is judged. Whether the echo signal is credible, the credible echo signal is used to calculate the detection result.
  • the technical solutions provided by the embodiments of this specification can improve the accuracy of the detection results, avoid signal distortion caused by signal saturation, circuit switching and/or drastic changes in environmental conditions, and effectively reduce the data false alarm rate of the laser gas telemeter.

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Abstract

本发明涉及激光遥测技术领域，特别涉及一种降低激光气体遥测仪数据误报率的方法和系统。其中，所述方法包括：获取标准信号光谱波形；获取回波信号光谱波形；计算所述回波信号光谱波形与所述标准信号光谱波形的相似度；基于所述相似度判断所述回波信号是否可信并生成判断结果；基于所述判断结果提取可信的回波信号并将其用于检测结果计算。所述系统包括数据采集单元、信号处理单元、判断单元和提取单元，该系统执行上述方法。本发明通过比较回波信号光谱波形与标准信号光谱波形的相似度，判断回波信号是否可信，采用可信的回波信号计算得到检测结果，有效提高检测结果的准确性，降低激光气体遥测仪的数据误报率。

Description

一种降低激光气体遥测仪数据误报率的方法和系统 技术领域
本发明涉及激光遥测技术领域，特别涉及一种降低激光气体遥测仪数据误报率的方法和系统。
背景技术
激光气体遥测仪是一种以激光为主要手段，实现远距离的遥感检测的设备。激光气体遥测仪常用于测定大气污染，如污染物的浓度。通过反射回波进行气体浓度测量是气体遥测的一种常见方式。由光源发出的光线经过准直照射到待测区域，光束被反射后产生的反射回波回到遥测装置的光电探测器中，通过测量反射回波被路径上目标气体的吸收可以推算出目标气体的浓度值。激光气体遥测仪无需在现场采样，能够实时检测现场的污染物浓度，如激光甲烷遥测仪能够现场检测甲烷浓度，判断是否有天然气泄漏或确定泄漏源位置。此外，激光气体遥测仪还具有速度快、灵敏度高和安全性高等优点。
但在实际应用中，激光气体遥测仪会受到检测环境条件变化、探测器饱和或电路切换等影响而出现数据误报现象。例如，检测环境光线中的日光或者接收到的反射光变化剧烈时，激光气体遥测仪获得的回波信号往往会发生畸变，这种畸变会导致测量结果错误，发生信号误报。
发明内容
针对现有技术的上述问题，本发明的目的在于，提供一种能够避免激光气体遥测仪受环境条件变化影响，降低激光气体遥测仪数据误报率的方法和系统。
本发明的具体技术方案如下：
第一方面，本发明提供一种降低激光气体遥测仪数据误报率的方法，包括：
获取标准信号光谱波形；
获取回波信号光谱波形；
计算所述回波信号光谱波形与所述标准信号光谱波形的相似度；
基于所述相似度判断所述回波信号是否可信并生成判断结果；
基于所述判断结果提取可信的回波信号并将其用于检测结果计算。
第二方面，本发明提供一种降低激光气体遥测仪数据误报率的系统，包括：
数据采集单元，被配置为获取标准信号光谱波形，和获取回波信号光谱波形；
信号处理单元，被配置为计算所述回波信号光谱波形与所述标准信号光谱波形的相似度；
判断单元，被配置为基于所述相似度判断所述回波信号是否可信并生成判断结果；
提取单元，被配置为基于所述判断结果提取可信的回波信号并将其用于检测结果计算。
所述检测结果包括气体浓度等数据。
第三方面，本发明提供一种激光气体遥测仪设备，包括：激光器、控制器、存储器和处理器，所述存储器上存储有至少一条指令、至少一段程序、代码集或指令集，所述至少一条指令、所述至少一段程序、所述代码集或指令集由所述处理器加载并执行以实现上述的降低激光气体遥测仪数据误报率的方法。
采用上述技术方案，本发明所述的降低激光气体遥测仪数据误报率的方法和系统具有如下有益效果：
本发明中将回波信号光谱波形与标准信号光谱波形做相似度比较，根据相似度值判断回波信号是否可信，采用可信的回波信号计算得到检测结果。利用本发明提供的技术方案可以提高检测结果的准确性，避免因信号饱和、电路切换和/或环境条件剧烈变化所导致的信号失真，有效降低激光气体遥测仪的数据误报率。
附图说明
为了更清楚地说明本发明的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单的介绍。显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它附图。
图1本发明实施例提供的一种激光气体遥测仪设备的结构示意图；
图2本发明实施例提供的一种降低激光气体遥测仪数据误报率的方法的流 程示意图；
图3本发明实施例提供的一组标准信号光谱波形(图a)和在周围环境强光干扰下获得的回波信号光谱波形(图b-i)；
图4本发明实施例提供的标准信号光谱波形的特征区域的划分示意图；
图5本发明实施例提供的另一标准信号光谱波形的特征区域的划分示意图；
图6本发明实施例提供的另一组回波信号光谱波形(图a-d)；
图7本发明实施例提供的一种降低激光气体遥测仪数据误报率的系统的结构示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动的前提下所获得的所有其他实施例，都属于本发明保护的范围。
需要说明的是，本发明的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的本发明的实施例能够以除了在这里图示或描述的那些以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、装置、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
请参考图1，图1是本发明实施例提供的一种激光气体遥测仪设备的结构示意图，如图1所示，该设备可以包括激光器、信号探测器、显示器、控制器、存储器和处理器等。还可以包括通信装置。该处理器中可以包括光谱分析器和信号检测处理器等。该设备可以设有测距器件和气体传感器件。
需要说明的是，上述设备可以是能够单独使用的设备，如手持式激光甲烷遥测仪等，也可以是能够集成在其他设备上使用的设备，例如能够集成在车辆、无人机或船只等上的激光甲烷遥测仪等。
在实际应用中，上述设备中激光器可以是可调谐二极管激光器，上述设备 可以是基于可调谐二极管激光吸收光谱(Tunable Diode Laser Absorption Spectroscopy，TDLAS)技术进行气体浓度检测。
以下介绍本发明基于上述设备的降低激光气体遥测仪数据误报率的方法，图2是本发明实施例提供的一种降低激光气体遥测仪数据误报率的方法的流程示意图。本说明书提供了如实施例或流程图所述的方法操作步骤，但基于常规或者无创造性的劳动可以包括更多或者更少的操作步骤。实施例中列举的步骤顺序仅仅为众多步骤执行顺序中的一种方式，不代表唯一的执行顺序。在实际中的系统或设备产品执行时，可以按照实施例或者附图所示的方法顺序执行或者并行执行。具体的如图2所示，所述方法可以包括：
S100，获取标准信号光谱波形；
本说明书实施例中，用于执行本说明书中方法的设备或系统可以预存有标准信号光谱波形，该标准信号光谱波形可以是在标准设置的实验条件下获得的测试结果。或者可以是在检测现场选取符合标准条件的环境，将获取到的回波信号光谱波形作为标准信号光谱波形。例如是在检测现场的环境中，选择没有待测气体的环境范围，采用标准反射面得到回波信号光谱波形，将其作为标准信号光谱波形。
在实际应用中，如果标准信号光谱波形为预存，则可以预存不止一个标准信号光谱波形，例如可以存储有室内无灯光条件下得到的标准信号光谱波形、城市室外空气条件下获得的标准信号光谱波形等。
S200，获取回波信号光谱波形；
本说明书实施例中，回波信号光谱波形是激光被环境中的待测气体吸收后，经反射面反射生成的回波信号，将该回波信号进行采样后得到回波信号光谱波形，本发明中获得回波信号光谱波形与获得标准信号光谱波形的激光器驱动电流的波形和周期相同。
本说明书实施例中，回波信号光谱波形可能会受到检测现场的环境因素影响而产生畸变，所述环境因素包括但不限于环境光线变化剧烈和/或接收到的反射光变化剧烈。例如在户外检测环境中日照光线的剧烈变化，检测现场的反射面具有不同的反射率或者反射面与激光束具有不同反射角等。
图3是本发明实施例提供一组标准信号光谱波形(图a)和在周围环境强光(采用取暖器模拟强光源)干扰下获得的回波信号光谱波形(图b-i)，请参考 图3，与标准信号光谱波形(图a)相比，回波信号光谱波形(图b-i)发生了明显的畸变，与标准信号光谱波形的相似性很差。
S300，计算所述回波信号光谱波形与所述标准信号光谱波形的相似度；
本说明书实施例中，采用的相似度计算公式为：
Figure PCTCN2020071612-appb-000001
其中，x为所述标准信号光谱波形中某一采样点的纵坐标值，y为所述回波信号光谱波形中同一采样点的纵坐标值，x 0为所述标准信号光谱波形的全部或某一区域范围内所有采样点纵坐标的平均值，y 0为回波信号光谱波形与所述标准信号光谱波形对应的全部或某一区域范围内所有采样点纵坐标的平均值，r xy为所述回波信号光谱波形与所述标准信号光谱波形的相似度
S400，基于所述相似度判断所述回波信号是否可信并生成判断结果；
本说明书实施例中，得到上述回波信号光谱波形与标准信号光谱波形的相似度后，判断所述相似度是否低于相似度阈值；若是，则确定所述回波信号不可信，舍弃所述回波信号；若否，则确定所述回波信号可信。
在一个具体实施例中，根据上述公式得到图3中在周围环境强光干扰下获得的回波信号光谱波形和标准光谱波形的相似度，确定图b-i对应的光谱为失真光谱，即图b-i对应的回波信号不可信。
S500，基于所述判断结果提取可信的回波信号并将其用于检测结果计算。
本说明书实施例中，可以设定为提取相似度值大于等于相似度阈值的回波信号以计算检测结果。
在实际应用中，将每次检测接收到的回波信号光谱波形和标准光谱波形做相关运算，从而得到一系列相似度结果，根据该结果和设定的相似度阈值比较，能够区分可信的和不可信的回波信号。进而舍弃不可信的回波信号，选取可信回波信号进行检测结果的计算(所述检测结果包括气体浓度等数据)，提高了测试的准确性。可以避免因信号饱和、电路切换、环境条件剧烈变化(如光线)等导致的信号失真或畸变，有效降低数据误报率。
在实际应用中，所述相似度阈值的范围优选为0.85-0.95。
本说明书的一些实施例中，步骤S300可以具体包括：
S310，根据所述标准信号光谱波形确定特征区域；
在说明书的实施例中，所述特征区域为标准信号光谱波形中不包括待测气体及环境干扰气体吸收的采样点范围。例如对于待测气体为甲烷的情况，所述 特征区域为标准信号光谱波形中不包括甲烷及环境干扰气体(如水蒸气、CO 2等)吸收的采样点范围。对于可调谐二极管激光器驱动电流是与激光器输出波长及光强相关的(标准信号光谱波形在给定驱动电流条件下获得，其采样点与波长相关)，而甲烷及环境干扰气体(如水蒸气、CO2等)的吸收波长是已知的，选择不包括甲烷及环境干扰气体(如水蒸气、CO2等)吸收的采样点范围为特征区域。
需要注意的是，所述的特征区域范围可以包含多个区域，该区域范围可以是分散的或者连续的。
S320，计算所述特征区域内的所述回波信号光谱波形与所述标准信号光谱波形的相似度。
本说明书的实施例中，上述采用的相似度计算公式中，x和y所指代的含义与上文相同，x 0为所述标准信号光谱波形的特征区域内所有采样点纵坐标的平均值，y 0为回波信号光谱波形的特征区域内所有采样点纵坐标的平均值。
进一步地，在本说明书的一些实施例中，所述步骤S310可以具体包括：
S311，确定特征区域边界点；
以待测气体吸收峰对应的采样点为参考点，特征区域接近待测气体吸收峰侧的边界点为第一边界点，特征区域远离待测气体吸收峰侧的边界点为第二边界点，第一边界点与参考点的距离参照待测气体吸收谱线的全宽设置，并参照实际计算需要设置第二边界点。
S312，根据边界点确定特征区域；
第一边界点与第二边界点间的范围即为特征区域。
事实上，特征区域通常为n个，其中，n为大于等于1的正整数。
如此，确定特征区域，对采样点进行初步筛选，减少了用于相关计算的采样点总量，进而降低了相关运算的运算量，大幅缩短计算时间，节省时间成本并降低了对硬件的要求。
在一个具体实施例中，请参考图4，图4中的两个方框圈定的部分为标准信号光谱波形上确定的特征区域。具体地，待测气体的吸收峰对应的参考点为S，该标准信号光谱波形在一个电流驱动周期内包括两个特征区域，标准信号光谱波形纵坐标代表光强。第一特征区域，对应采样点为0-300，即第一边界点A对应的采样点为0，第二边界点B对应的采样点为300，该区域整体光强较弱；第 二特征区域，对应采样点为1300-1800，即第三边界点C对应的采样点为1300，第四边界点D对应的采样点为1800，该区域的整体光强较强。以第一特征区域和第二特征区域作为特征区域。将所述特征区域内的采样点作为用于计算相似度的采样点。
在一个具体实施例中，基于上述图4中标准信号光谱波形所确定的特征区域，采样点0-300和采样点1300-1800。根据相似度计算公式，x为标准信号光谱波形中某一采样点的纵坐标(光强)值，y为所述回波信号光谱波形中与标准信号光谱波形中同一采样点的纵坐标(光强)值，x 0为标准信号光谱波形中该特征区域内800个采样点纵坐标(光强)的平均值，y 0为回波信号光谱波形中该特征区域内800个采样点纵坐标的平均值。
在另一个具体实施例中，请参考图5，图5中的两个方框圈定的部分为标准信号光谱波形上确定的特征区域，具体地，待测气体的吸收峰对应的第一参考点为S 1，第二参考点为S 2。第一边界点A'，第二边界点B'，第三边界点C'和第四边界点D'对应的采样点分别为500，700，1000和1300，即第一特征区域对应的采样点范围是500-700，整体光强较强，第二特征区域对应的采样点范围是1000-3000，整体光强较弱。以第一特征区域和第二特征区域内的采样点作为用于计算相似度的采样点。
基于上述具体实施方式，在本说明书的一些实施例中，特征区域内可以包括光谱波形上光强发生剧烈变化的区域，例如包括曲线弯折点或曲线拐点等。
本实施例中，经试验验证，确定相似度阈值为0.9。进一步地，请参照图6，根据上文所述的相似度计算公式和图4中确定的特征区域，图a-d中回波信号光谱波形与图4中标准信号光谱波形的相似度依次为：0.999、0.985、0.8和0.7。因此，确定图a和b对应的回波信号可信，用于检测结果计算；图c和d对应的回波信号不可信，做舍弃处理。
以下介绍本发明基于上述设备的一种降低激光气体遥测仪数据误报率的系统，图7是本发明实施例提供的一种降低激光气体遥测仪数据误报率的系统的结构示意图，结合图7，所述系统可以包括：
数据采集单元10，被配置为获取标准信号光谱波形，和获取回波信号光谱波形；
信号处理单元20，被配置为计算所述回波信号光谱波形与所述标准信号光 谱波形的相似度；
判断单元30，被配置为基于所述相似度判断所述回波信号是否可信并生成判断结果；
提取单元40，被配置为基于所述判断结果提取可信的回波信号并将其用于检测结果计算。
进一步的，在一些实施例中，所述信号处理单元20可以包括：
分析模块，可以被配置为根据所述标准信号光谱波形确定特征区域；
算法模块，可以被配置为计算所述特征区域内的所述回波信号光谱波形与所述标准信号光谱波形的相似度。
具体地，在一些实施例中，所述算法模块可以被配置为根据相计算公式
Figure PCTCN2020071612-appb-000002
计算所述相似度；
其中，x为所述标准信号光谱波形中某一采样点的纵坐标值，y为所述回波信号光谱波形中与所述标准信号光谱波形中同一采样点的纵坐标值，x 0为所述标准信号光谱波形的特征区域内所有采样点纵坐标的平均值，y 0为回波信号光谱波形的特征区域内所有采样点纵坐标的平均值。
进一步的，在一些实施例中，所述分析模块还可以被配置为：
确定所述标准信号光谱波形上不包括待测气体及环境干扰气体吸收的采样点范围为特征区域，所述特征区域为n个，其中，n为大于等于1的正整数。进一步的，在一些实施例中，所述判断单元30可以被配置为判断所述相似度是否低于相似度阈值；
若是，则确定所述回波信号不可信，舍弃所述回波信号；
若否，则确定所述回波信号可信。
由上述本发明提供的降低激光气体遥测仪数据误报率的方法、系统或设备的实施例可见，本发明中将回波信号光谱波形与标准信号光谱波形做相似度比较，根据相似度值判断回波信号是否可信，采用可信的回波信号计算得到检测结果。利用本说明书实施例提供的技术方案可以提高检测结果的准确性，避免因信号饱和、电路切换和/或环境条件剧烈变化所导致的信号失真，有效降低激光气体遥测仪的数据误报率。
以上所述仅为本发明的较佳实施例，并不用以限制本发明，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的 保护范围之内。

Claims (10)

  1. 一种降低激光气体遥测仪数据误报率的方法，其特征在于，包括：
    获取标准信号光谱波形；
    获取回波信号光谱波形；
    计算所述回波信号光谱波形与所述标准信号光谱波形的相似度；
    基于所述相似度判断所述回波信号是否可信并生成判断结果；
    基于所述判断结果提取可信的回波信号并将其用于检测结果计算。
  2. 根据权利要求1所述的方法，其特征在于，所述计算所述回波信号光谱波形和所述标准信号光谱波形相似度，包括：
    根据所述标准信号光谱波形确定特征区域；
    计算所述特征区域内的所述回波信号光谱波形与所述标准信号光谱波形的相似度。
  3. 根据权利要求2所述的方法，其特征在于，所述相似度的计算公式为：
    Figure PCTCN2020071612-appb-100001
    其中，x为所述标准信号光谱波形中某一采样点的纵坐标值，y为所述回波信号光谱波形中同一采样点的纵坐标值，x 0为所述标准信号光谱波形的特征区域内所有采样点纵坐标的平均值，y 0为回波信号光谱波形的特征区域内所有采样点纵坐标的平均值，r xy为所述回波信号光谱波形与所述标准信号光谱波形的相似度。
  4. 根据权利要求2所述的方法，其特征在于，所述根据所述标准信号光谱波形确定特征区域，包括：
    确定所述标准信号光谱波形上不包括待测气体及环境干扰气体吸收的采样点范围为特征区域；
    所述特征区域为n个，其中，n为大于等于1的正整数。
  5. 根据权利要求1所述的方法，其特征在于，所述根据所述相似度结果判断所述回波信号是否可信并生成判断结果，包括：
    判断所述相似度是否低于相似度阈值；
    若是，则确定所述回波信号不可信，舍弃所述回波信号；
    若否，则确定所述回波信号可信。
  6. 一种降低激光气体遥测仪数据误报率的系统，其特征在于，包括：
    数据采集单元(10)，被配置为获取标准信号光谱波形，和获取回波信号光谱波形；
    信号处理单元(20)，被配置为计算所述回波信号光谱波形与所述标准信号光谱波形的相似度；
    判断单元(30)，被配置为基于所述相似度判断所述回波信号是否可信并生成判断结果；
    提取单元(40)，被配置为基于所述判断结果提取可信的回波信号并将其用于检测结果计算。
  7. 根据权利要求6所述的系统，其特征在于，所述信号处理单元(20)包括：
    分析模块，被配置为根据所述标准信号光谱波形确定特征区域；
    算法模块，被配置为计算所述特征区域内的所述回波信号光谱波形与所述标准信号光谱波形的相似度。
  8. 根据权利要求7所述的系统，其特征在于，所述算法模块被配置为根据公式
    Figure PCTCN2020071612-appb-100002
    计算所述相似度；
    其中，x为所述标准信号光谱波形中某一采样点的纵坐标值，y为所述回波信号光谱波形中同一采样点的纵坐标值，x 0为所述标准信号光谱波形的特征区域内所有采样点纵坐标的平均值，y 0为回波信号光谱波形的特征区域内所有采样点纵坐标的平均值，r xy为所述回波信号光谱波形与所述标准信号光谱波形的相似度。
  9. 根据权利要求7所述的系统，其特征在于，所述分析模块还被配置为：确定所述标准信号光谱波形上不包括待测气体及环境干扰气体吸收的的采样点 范围为特征区域；
    所述特征区域为n个，其中，n为大于等于1的正整数。
  10. 根据权利要求6所述的系统，其特征在于，所述判断单元(30)被配置为判断所述相似度是否低于相似度阈值；
    若是，则确定所述回波信号不可信，舍弃所述回波信号；
    若否，则确定所述回波信号可信。
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