Hydrocarbon contamination detection method and apparatus coupling spectral subtraction with feature t-test

Abstract

The application provides a hydrocarbon pollution detection method and device coupled with spectral difference subtraction and characteristic T test, and belongs to the technical field of environmental monitoring. The method comprises the following steps: obtaining target near-infrared spectrum data of a detection area; determining corresponding background near-infrared spectrum data according to the ground feature type of the detection area, wherein the background near-infrared spectrum data is the reference spectrum data of the same ground feature as the detection target and not polluted by hydrocarbon; performing difference subtraction processing on the target near-infrared spectrum data and the background near-infrared spectrum data to generate a difference spectrum; selecting a hydrocarbon characteristic absorption wave band and a reference wave band, and performing independent sample T test on the spectrum value of the difference spectrum in the hydrocarbon characteristic absorption wave band and the spectrum value in the reference wave band; and determining the hydrocarbon pollution detection result of the detection area based on the test result. The application eliminates background interference through spectral difference subtraction, establishes an objective judgment standard by using T test, and improves the scientificity and applicability of hydrocarbon pollution detection.

Description

Technical Field

[0001] This invention relates to the field of environmental monitoring technology, and in particular to a method and apparatus for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test. Background Technology

[0002] With the acceleration of industrialization, the environmental pollution caused by hydrocarbon leaks is becoming increasingly serious. Near-infrared spectroscopy is widely used in the detection of hydrocarbon pollution in environmental media such as soil and water due to its advantages of being fast, non-destructive, and requiring no sample pretreatment.

[0003] However, existing near-infrared spectroscopy detection methods still have limitations in practical applications. On the one hand, detection scenarios are often complex, and the spectral characteristics of ground features often mask or interfere with the characteristic absorption of hydrocarbons, making direct identification difficult. On the other hand, current determinations of hydrocarbon pollution mainly rely on spectral values ​​in characteristic bands or their simple calculations, and the threshold settings are often based on human experience or fixed standards. Due to the high uncertainty of pollution levels and environmental interference factors in real-world scenarios, such thresholds based on subjective experience lack statistical scientific basis, have poor applicability, and are prone to misjudgment or missed detection results. Summary of the Invention

[0004] This invention provides a method and apparatus for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test, in order to overcome the shortcomings of existing hydrocarbon pollution detection methods in terms of poor scientific validity and applicability.

[0005] This invention provides a method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test, comprising:

[0006] Acquire the target near-infrared spectral data of the area to be detected, and determine the corresponding background near-infrared spectral data according to the land cover type of the area to be detected. The background near-infrared spectral data is the reference spectral data of the same land cover as the target to be detected and not contaminated by hydrocarbons.

[0007] The target near-infrared spectral data and the background near-infrared spectral data are subtracted to generate a difference spectrum.

[0008] In the difference spectrum, a hydrocarbon characteristic absorption band and a reference band are selected. An independent samples T-test is performed on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption band and the spectral values ​​in the reference band to obtain the test results.

[0009] Based on the test results, the hydrocarbon pollution detection results for the area to be tested are determined.

[0010] In some embodiments, the hydrocarbon characteristic absorption band is a band corresponding to the absorption frequency of the CH bond vibration of hydrocarbon substances, the reference band is a weak absorption band of ground objects, and the reference band is outside the hydrocarbon characteristic absorption band.

[0011] In some embodiments, the characteristic absorption band of hydrocarbons is a band within the wavelength range of 1700nm-1780nm; the reference band is a band within the wavelength range of 1560nm-1640nm.

[0012] In some embodiments, performing an independent samples T-test on the spectral values ​​of the difference spectrum within the characteristic absorption band of the hydrocarbon and the spectral values ​​within the reference band includes:

[0013] Calculate the first spectral mean, first spectral variance, and first number of data points of the difference spectrum within the characteristic absorption band of the hydrocarbon;

[0014] Calculate the second spectral mean, second spectral variance, and second number of data points of the difference spectrum within the reference band;

[0015] Based on the first spectral mean, the first spectral variance, and the first number of data points, and the second spectral mean, the second spectral variance, and the second number of data points, calculate... t Statistic, the t The statistic is used to measure the significance of the difference in mean values ​​between the difference spectrum and the reference spectrum in the hydrocarbon characteristic absorption band.

[0016] In some embodiments, the t The formula for calculating the statistic is as follows:

[0017] ;

[0018] in, t Indicates the t Statistic, This represents the mean of the first spectrum. Indicates the variance of the first spectrum. This indicates the number of the first data points; This represents the mean of the second spectrum. This represents the variance of the second spectrum. This indicates the number of the second data points.

[0019] In some embodiments, determining the hydrocarbon pollution detection result of the area to be detected based on the test result includes:

[0020] Comparison t The statistical measure is compared with a preset significance threshold, and the mean of the first spectrum is compared with the mean of the second spectrum;

[0021] If the following conditions are met simultaneously, the area to be detected is determined to be contaminated with hydrocarbons:

[0022] The t The absolute value of the statistic is not less than the significance threshold.

[0023] The mean value of the first spectrum is less than 0;

[0024] The mean value of the first spectrum is less than the mean value of the second spectrum.

[0025] In some embodiments, both the target near-infrared spectral data and the background near-infrared spectral data satisfy the following conditions: the spectral range covers 1100nm-2400nm; and the spectral resolution is not less than 12nm.

[0026] The present invention also provides a hydrocarbon pollution detection device that couples spectral difference subtraction with characteristic T test, comprising:

[0027] The acquisition unit is used to acquire the target near-infrared spectral data of the area to be detected, and determine the corresponding background near-infrared spectral data according to the land cover type of the area to be detected. The background near-infrared spectral data is the reference spectral data of the same type of land cover as the target to be detected and not contaminated by hydrocarbons.

[0028] The processing unit is used to perform a difference subtraction process on the target near-infrared spectral data and the background near-infrared spectral data to generate a difference spectrum;

[0029] The testing unit is used to select a hydrocarbon characteristic absorption band and a reference band in the difference spectrum, and to perform an independent samples T-test on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption band and the spectral values ​​in the reference band to obtain the test results;

[0030] The determining unit is used to determine the hydrocarbon pollution detection result of the area to be detected based on the test result.

[0031] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the hydrocarbon pollution detection method of coupling spectral difference subtraction and characteristic T test as described above.

[0032] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the hydrocarbon pollution detection method coupled with spectral difference subtraction and characteristic T test as described above.

[0033] The present invention provides a method and apparatus for detecting hydrocarbon pollution using coupled spectral subtraction and characteristic T-test. This method acquires target near-infrared spectral data of the area to be detected and determines corresponding background near-infrared spectral data based on the land cover type of the area. The target near-infrared spectral data and the background near-infrared spectral data are subtracted to generate a difference spectrum, effectively eliminating interference from complex land cover backgrounds. In the difference spectrum, hydrocarbon characteristic absorption bands and reference bands are selected. An independent samples T-test is performed on the spectral values ​​of the difference spectrum within the hydrocarbon characteristic absorption bands and the spectral values ​​within the reference bands to obtain the test results. The T-test focuses on the relative significance of differences between bands and has strong adaptability. Based on the test results, the hydrocarbon pollution detection results for the area to be detected are determined, greatly improving the scientific validity and accuracy of the detection results. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic flowchart of the hydrocarbon pollution detection method based on coupled spectral difference subtraction and characteristic T-test provided in this embodiment of the invention.

[0036] Figure 2 This is a schematic diagram of the process for performing an independent sample T-test on the difference spectrum provided in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the structure of the hydrocarbon pollution detection device coupled with spectral difference subtraction and characteristic T test provided in the embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] The terms "first," "second," etc., used in this invention are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, not limited in number; for example, the first object can be one or more. Furthermore, in this invention, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0041] Figure 1 This is a schematic flowchart of the hydrocarbon pollution detection method coupled with spectral difference subtraction and characteristic T-test provided in an embodiment of the present invention. Figure 1 As shown, a method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test is provided, including the following steps: step 110, step 120, step 130, and step 140. This method's steps are merely one possible implementation of the invention.

[0042] Step 110: Obtain the target near-infrared spectral data of the area to be detected. Based on the land cover type of the area to be detected, determine the corresponding background near-infrared spectral data. The background near-infrared spectral data is the reference spectral data of the same type of land cover as the target to be detected and which is not contaminated by hydrocarbons.

[0043] The area to be tested refers to a geographical area or sample point that may be contaminated by hydrocarbons; hydrocarbons include, but are not limited to, petroleum, diesel and gasoline; the medium of the area to be tested includes at least soil, water or other environmental substrates.

[0044] The target near-infrared spectral data includes near-infrared band spectral information directly acquired from the area to be detected. Acquisition methods include, but are not limited to: ground-based measurements using a near-infrared spectrometer, or acquiring hyperspectral or multispectral image data using an imaging spectrometer mounted on a drone, satellite, or vehicle platform.

[0045] Background near-infrared spectral data refers to spectral data collected in areas with the same or similar land cover types as the area to be detected, and which have been confirmed to be free from hydrocarbon contamination. This data serves as baseline spectral data for subsequent background interference removal. The methods for acquiring background near-infrared spectral data can be flexibly chosen. For example, a clean area with the same land cover type but clearly uncontaminated can be found near the area to be detected for spectral acquisition; alternatively, a standard clean spectral database for different land cover types can be pre-established, and the corresponding spectral curve can be retrieved from the database based on the identified land cover type; furthermore, for imaging spectral data, image processing techniques can be used to extract the average spectral value of background pixels around the pixel to be detected that are determined to be uncontaminated.

[0046] In some embodiments, both the target near-infrared spectral data and the background near-infrared spectral data satisfy the following: the spectral range covers 1100nm-2400nm; and the spectral resolution is not less than 12nm.

[0047] It should be noted that the 1100nm-2400nm wavelength range encompasses several key overtone and combination frequency absorption features of CH bond vibrations in hydrocarbons, and also includes weak absorption regions of ground features used for selecting background references. If the spectral range is too narrow, crucial feature information may be missed or a suitable reference point may not be found. Since the absorption peaks of hydrocarbons in the near-infrared region often have a certain width, they also possess some subtle fingerprint characteristics. If the resolution is too low, i.e., greater than 12nm, the characteristic absorption peaks may be smoothed or blurred, making the signal characteristics in the difference spectrum indistinct, thus affecting the statistical significance determination of the T-test. Therefore, setting a resolution lower limit of 12nm is a necessary condition to ensure the effective extraction of hydrocarbon characteristic signals.

[0048] In practice, portable ground object spectrometers or hyperspectral imagers can be used to acquire data that meets the above parameter requirements.

[0049] Step 120: Subtract the target near-infrared spectral data from the background near-infrared spectral data to generate a difference spectrum.

[0050] In this step, the core purpose of the subtraction processing is to eliminate the masking effect of the weak hydrocarbon signals by the spectral characteristics of the ground background itself. Specifically, it involves subtracting the spectral values ​​of the target near-infrared spectral data from the background near-infrared spectral data at corresponding wavelengths to obtain the difference spectrum.

[0051] Understandably, through this differential operation, most of the common background absorption characteristics caused by soil minerals, moisture, and vegetation chlorophyll are canceled out, while the specific spectral changes in the area under test caused by hydrocarbon pollution are preserved and highlighted in the difference spectrum. This improves the signal-to-noise ratio at a physical level, laying a data foundation for subsequent statistical tests.

[0052] Step 130: In the difference spectrum, select the characteristic absorption band of hydrocarbons and the reference band, and perform an independent samples T-test on the spectral values ​​of the difference spectrum in the characteristic absorption band of hydrocarbons and the spectral values ​​in the reference band to obtain the test results.

[0053] The hydrocarbon characteristic absorption band refers to the wavelength range in which hydrocarbons are known to exhibit significant absorption characteristics. Because hydrocarbons are rich in CH bonds, they possess characteristic absorption peaks in the near-infrared region generated by overtones or combination frequencies of CH bond vibrations. This band can be selected to capture pollution signals.

[0054] The reference band refers to the wavelength range where absorption is weak or gradual in the background of ground features and is less affected by hydrocarbon pollution. This band is selected to provide a relatively stable reference standard, representing the noise level or baseline level of the spectrum when there are no significant characteristic changes.

[0055] The independent samples t-test is a statistical hypothesis testing method used to determine whether there is a significant difference between the means of two independent samples. In this embodiment, instead of comparing two different physical samples, the set of spectral values ​​of the difference spectrum within the characteristic absorption band of hydrocarbons is regarded as the first sample group, and the set of spectral values ​​of the difference spectrum within the reference band is regarded as the second sample group.

[0056] In practice, all data points within the two bands of the difference spectrum are extracted, and statistical measures for the two sets of data, such as mean, variance, and sample size, are calculated. t The test statistic and its corresponding significance probability. The test results should include at least the following: t Statistics and their corresponding significance probabilities.

[0057] Step 140: Based on the test results, determine the hydrocarbon pollution detection results for the area to be tested.

[0058] Optionally, determine t Whether the statistical value exceeds the critical value and whether the significance probability p is less than the preset probability threshold are used to determine whether hydrocarbon pollution exists.

[0059] For example, if the test results show that the spectral value of the characteristic absorption band of hydrocarbons is significantly lower than that of the reference band, and the significance level of the difference meets the preset requirements, such as p<0.05, then the hydrocarbon pollution detection result is determined to be positive, that is, pollution exists; otherwise, if the difference is not significant, it is determined to be negative, that is, there is no pollution.

[0060] In this embodiment of the invention, target near-infrared spectral data of the area to be detected is acquired, and corresponding background near-infrared spectral data is determined according to the land cover type of the area to be detected. The target near-infrared spectral data and the background near-infrared spectral data are subtracted to generate a difference spectrum, which effectively eliminates the interference of complex land cover background. In the difference spectrum, hydrocarbon characteristic absorption bands and reference bands are selected, and independent samples t-tests are performed on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption bands and the spectral values ​​in the reference bands to obtain the test results. The t-test focuses on the relative significance of differences between bands and has strong adaptability. Based on the test results, the hydrocarbon pollution detection results of the area to be detected are determined, which greatly improves the scientificity and accuracy of the detection results.

[0061] In some embodiments, the hydrocarbon characteristic absorption band is the band corresponding to the absorption frequency of the CH bond vibration of hydrocarbon substances, the reference band is the weak absorption band of ground objects, and the reference band is outside the hydrocarbon characteristic absorption band.

[0062] It should be noted that hydrocarbon molecules contain a large number of carbon-hydrogen bonds (CH), and their molecular vibrations produce specific overtone or combination frequency absorptions in the near-infrared region. Selecting this band as the characteristic band can maximize the capture of the specific response signals of hydrocarbon pollutants, ensuring targeted detection.

[0063] Within the weak absorption band of ground features, common ground features, such as clay minerals and rock components in soil, have minimal absorption of the spectrum, or their absorption characteristics are relatively flat and do not exhibit drastic fluctuations. The purpose of selecting this band is to construct a reference baseline. Requiring the reference band to be located outside the characteristic band is to ensure the independence of the two sets of sample data and avoid signal aliasing affecting the statistical validity of the t-test.

[0064] In some embodiments, the characteristic absorption band of hydrocarbons is a band within the wavelength range of 1700nm-1780nm; the reference band is a band within the wavelength range of 1560nm-1640nm.

[0065] It should be noted that 1700nm-1780nm was chosen as the characteristic absorption band for hydrocarbons because this range corresponds to the absorption peak position of the first-order overtone stretching vibration of the CH bond. In actual reflectance spectra, this band usually shows a significant absorption dip when hydrocarbon pollution is present. 1560nm-1640nm was chosen as the reference band because this range lies in the relatively transparent window between the absorption peaks of water and clay minerals, minimizing interference from ground background. Furthermore, it is close to the characteristic hydrocarbon band and less affected by instrument baseline drift, making it ideal for comparative reference.

[0066] It should be noted that the selection of the above-mentioned band range is based on the optimization results obtained from a large amount of experimental data. However, in practical applications, the boundary values ​​of the above-mentioned bands can be fine-tuned within a certain range according to different sensor types or specific differences in hydrocarbon components. As long as the principle of significant features and stable reference is followed, they all fall within the protection scope of this application.

[0067] This embodiment, by clearly defining the specific physical meaning and preferred numerical range of the hydrocarbon characteristic absorption bands and reference bands, ensures that the characteristic samples participating in the T-test accurately reflect pollution information, while also ensuring that the reference samples have high stability and low noise interference. This band combination selection strategy maximizes the statistical difference between the signal and the background, thereby further improving the significance of the T-test results and the sensitivity of the detection.

[0068] Figure 2 This is a schematic diagram illustrating the process of performing an independent samples T-test on the difference spectrum according to an embodiment of the present invention. Figure 2 As shown, in some embodiments, step 130 involves performing an independent samples T-test on the spectral values ​​of the difference spectrum within the characteristic absorption band of hydrocarbons and the spectral values ​​within the reference band, including:

[0069] Step 131: Calculate the first spectral mean, first spectral variance, and first number of data points of the difference spectrum within the characteristic absorption band of hydrocarbons.

[0070] Among them, the first spectral mean refers to the arithmetic mean of all spectral values ​​within the hydrocarbon characteristic absorption band, which reflects the overall signal intensity level within the hydrocarbon characteristic absorption band; the first spectral mean refers to the variance of the spectral data within the hydrocarbon characteristic absorption band, which is used to measure the dispersion or volatility of the data distribution within this band; the first data point number refers to the number of sampling points contained within the hydrocarbon characteristic absorption band, the value of which depends on the spectral resolution and band width.

[0071] Step 132: Calculate the second spectral mean, second spectral variance, and second data point number of the difference spectrum within the reference band.

[0072] The second spectral mean refers to the arithmetic mean of all spectral values ​​within the reference band, reflecting the overall signal strength level within the reference band; the second spectral mean refers to the variance of the spectral data within the reference band, used to measure the dispersion or volatility of the data distribution within that band; and the number of second data points refers to the number of sampling points contained within the reference band.

[0073] Step 133: Based on the first spectral mean, the first spectral variance, and the first number of data points, and the second spectral mean, the second spectral variance, and the second number of data points, calculate... t Statistic, t The statistic is used to measure the significance of the difference in mean values ​​between the characteristic absorption bands of hydrocarbons and the reference bands in the difference spectrum.

[0074] Optionally, Welch's t-test can be used to calculate... t Statistics.

[0075] In some embodiments, t The formula for calculating the statistic is as follows:

[0076] ;

[0077] in, t express t Statistic, Indicates the mean of the first spectrum. Indicates the variance of the first spectrum. Indicates the number of the first data points; Indicates the mean of the second spectrum. Indicates the variance of the second spectrum. This indicates the number of the second data points.

[0078] It should be noted that the calculated t The larger the absolute value of the statistic, the more significant the difference between the two bands, and the less likely it is to be caused by random noise alone. This quantitative indicator provides a solid mathematical basis for subsequent objective determination of whether hydrocarbon pollution exists.

[0079] This embodiment clarifies the calculation logic and specific formula for the core statistic in the T-test. It calculates the mean, variance, and sample size of the characteristic band and the reference band separately, and then synthesizes the statistic using Welch's T-test formula. t This statistical method enables precise quantification of differences between wavebands. It considers not only the magnitude of light intensity but also the stability of the signal and the scale of the data, thus statistically minimizing random errors and ensuring the final result is accurate. t The value can accurately and objectively reflect the significance of hydrocarbon characteristic signals relative to background noise, thus enhancing the scientific nature of pollution determination.

[0080] In some embodiments, the hydrocarbon pollution detection results for the area to be tested are determined based on the test results, including:

[0081] Compare t The statistical measure is compared with the preset significance threshold, and the mean of the first spectrum is compared with the mean of the second spectrum;

[0082] If the following conditions are met simultaneously, the area to be tested is determined to be contaminated with hydrocarbons:

[0083] t The absolute value of the statistic is not less than the significance threshold;

[0084] The mean value of the first spectrum is less than 0;

[0085] The mean of the first spectrum is less than the mean of the second spectrum.

[0086] Optionally, the corresponding significance threshold can be found or calculated based on a preset significance level and degrees of freedom. The degrees of freedom can be determined based on the number of the first data points and the number of the second data points.

[0087] Optionally, check the sign of the first spectral mean: determine the absolute direction of change of the characteristic band relative to the background spectrum.

[0088] It should be noted that, tThe absolute value of the statistic is not less than the significance threshold, indicating a significant difference between the characteristic absorption bands of hydrocarbons and the reference bands, meaning they are statistically significantly different. This is the basic threshold for judgment. Since hydrocarbon pollution usually leads to a decrease in near-infrared reflectance and an increase in absorption, the mean of the first spectrum should theoretically be negative in the polluted area. This condition confirms that the direction of change conforms to the strong absorption characteristics, excluding reverse bias caused by other factors, such as highly reflective foreign objects. The condition that the mean of the first spectrum is less than the mean of the second spectrum further strengthens the specificity of the judgment. Even if the overall difference spectrum is negative, for example, due to overall darkening of illumination conditions, if the decrease in the characteristic bands does not significantly exceed that of the reference bands, it cannot be concluded that it is hydrocarbon pollution. Only when the mean of the first spectrum is less than the mean of the second spectrum can the presence of specific hydrocarbon absorption characteristics be confirmed.

[0089] Conversely, if any of the above conditions are not met, it is determined that there is no hydrocarbon pollution in the area to be tested, or the pollution level is below the detection limit.

[0090] The triple joint judgment strategy proposed in this embodiment greatly improves the robustness and accuracy of the detection results; introducing t The statistical threshold ensures the statistical rigor of the judgment and avoids false positives caused by minor noise fluctuations; requiring the mean of the first spectrum to be less than 0 and less than the mean of the second spectrum ensures that the detected signal is an absorption enhancement signal rather than other anomalies; this multi-dimensional judgment logic can effectively filter out systematic errors and interference from non-target ground objects, thereby minimizing the misjudgment rate.

[0091] The hydrocarbon pollution detection device based on coupled spectral difference subtraction and characteristic T-test provided in the embodiments of the present invention will be described below. The hydrocarbon pollution detection device based on coupled spectral difference subtraction and characteristic T-test described below can be referred to in correspondence with the hydrocarbon pollution detection method based on coupled spectral difference subtraction and characteristic T-test described above.

[0092] Figure 3 This is a schematic diagram of the hydrocarbon pollution detection device coupled with spectral difference subtraction and characteristic T test provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the hydrocarbon pollution detection device 300 coupled with spectral difference subtraction and characteristic T-test includes:

[0093] The acquisition unit 310 is used to acquire the target near-infrared spectral data of the area to be detected, and to determine the corresponding background near-infrared spectral data according to the land cover type of the area to be detected. The background near-infrared spectral data is the reference spectral data of the same land cover as the target to be detected and which is not contaminated by hydrocarbons.

[0094] Processing unit 320 is used to perform difference subtraction processing on the target near-infrared spectral data and the background near-infrared spectral data to generate a difference spectrum;

[0095] The test unit 330 is used to select the characteristic absorption band of hydrocarbons and the reference band in the difference spectrum, and to perform an independent samples T-test on the spectral values ​​of the difference spectrum in the characteristic absorption band of hydrocarbons and the spectral values ​​in the reference band to obtain the test results.

[0096] The determination unit 340 is used to determine the hydrocarbon pollution detection results of the area to be tested based on the test results.

[0097] Optionally, the hydrocarbon characteristic absorption band is the band corresponding to the absorption frequency of the CH bond vibration of hydrocarbon substances, the reference band is the weak absorption band of ground objects, and the reference band is outside the hydrocarbon characteristic absorption band.

[0098] Optionally, the characteristic absorption band of hydrocarbons is the band within the wavelength range of 1700nm-1780nm; the reference band is the band within the wavelength range of 1560nm-1640nm.

[0099] Optionally, an independent samples T-test is performed on the spectral values ​​of the difference spectrum in the characteristic absorption band of hydrocarbons and the spectral values ​​in the reference band, including:

[0100] Calculate the first spectral mean, first spectral variance, and first number of data points of the difference spectrum within the characteristic absorption band of hydrocarbons;

[0101] Calculate the second spectral mean, second spectral variance, and second data point number of the difference spectrum within the reference band;

[0102] Based on the first spectral mean, first spectral variance, and first number of data points, and the second spectral mean, second spectral variance, and second number of data points, calculate... t Statistic, t The statistic is used to measure the significance of the difference in mean values ​​between the characteristic absorption bands of hydrocarbons and the reference bands in the difference spectrum.

[0103] Optionally, t The formula for calculating the statistic is as follows:

[0104] ;

[0105] in, t express t Statistic, Indicates the mean of the first spectrum. Indicates the variance of the first spectrum. Indicates the number of the first data points; Indicates the mean of the second spectrum. Indicates the variance of the second spectrum. This indicates the number of the second data points.

[0106] Optionally, based on the test results, the hydrocarbon pollution detection results for the area to be tested are determined, including:

[0107] Compare t The statistical measure is compared with the preset significance threshold, and the mean of the first spectrum is compared with the mean of the second spectrum;

[0108] If the following conditions are met simultaneously, the area to be tested is determined to be contaminated with hydrocarbons:

[0109] t The absolute value of the statistic is not less than the significance threshold;

[0110] The mean value of the first spectrum is less than 0;

[0111] The mean of the first spectrum is less than the mean of the second spectrum.

[0112] Optionally, both the target near-infrared spectral data and the background near-infrared spectral data meet the following requirements: the spectral range covers 1100nm-2400nm; and the spectral resolution is not less than 12nm.

[0113] It should be noted that the hydrocarbon pollution detection device coupled with spectral difference subtraction and characteristic T test provided in this embodiment of the invention can realize all the method steps implemented in the above-mentioned hydrocarbon pollution detection method embodiment coupled with spectral difference subtraction and characteristic T test, and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0114] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention, such as... Figure 4 As shown, the electronic device may include a processor 410, a communication interface 420, a memory 430, and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other via the communication bus 440. The processor 410 can call logical instructions in the memory 430 to execute a hydrocarbon pollution detection method coupled with spectral subtraction and characteristic T-test. This method includes: acquiring target near-infrared spectral data of the area to be detected; determining corresponding background near-infrared spectral data based on the land cover type of the area to be detected, wherein the background near-infrared spectral data is a reference spectral data unaffected by hydrocarbon pollution; performing subtraction processing on the target near-infrared spectral data and the background near-infrared spectral data to generate a difference spectrum; selecting a hydrocarbon characteristic absorption band and a reference band in the difference spectrum, performing an independent samples T-test on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption band and the spectral values ​​in the reference band, and obtaining the test result; and determining the hydrocarbon pollution detection result of the area to be detected based on the test result.

[0115] Furthermore, the logical instructions in the aforementioned memory 430 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0116] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a method for detecting hydrocarbon pollution using coupled spectral subtraction and characteristic T-tests provided by the methods described above. This method includes: acquiring target near-infrared spectral data of the area to be detected; determining corresponding background near-infrared spectral data based on the land cover type of the area to be detected, wherein the background near-infrared spectral data is reference spectral data of the same type of land cover as the target and not contaminated by hydrocarbons; performing subtraction processing on the target near-infrared spectral data and the background near-infrared spectral data to generate a difference spectrum; selecting a hydrocarbon characteristic absorption band and a reference band in the difference spectrum; performing an independent samples T-test on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption band and the spectral values ​​in the reference band to obtain the test result; and determining the hydrocarbon pollution detection result of the area to be detected based on the test result.

[0117] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0118] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test, characterized in that, include: Acquire the target near-infrared spectral data of the area to be detected, and determine the corresponding background near-infrared spectral data according to the land cover type of the area to be detected. The background near-infrared spectral data is the reference spectral data of the same land cover as the target to be detected and not contaminated by hydrocarbons. The target near-infrared spectral data and the background near-infrared spectral data are subtracted to generate a difference spectrum. In the difference spectrum, a hydrocarbon characteristic absorption band and a reference band are selected. An independent samples T-test is performed on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption band and the spectral values ​​in the reference band to obtain the test results. The reference band is outside the characteristic absorption band of the hydrocarbons; the test results include... t Statistic, the t The statistic is used to measure the significance of the difference in mean values ​​between the difference spectrum and the reference spectrum in the characteristic absorption band of hydrocarbons. Comparison t The statistical measure is compared with a preset significance threshold, and the first spectral mean of the difference spectrum in the characteristic absorption band of the hydrocarbon is compared with the second spectral mean of the difference spectrum in the reference band. If the following conditions are met simultaneously, the area to be detected is determined to be contaminated with hydrocarbons: The t The absolute value of the statistic is not less than the significance threshold. The mean value of the first spectrum is less than 0; The mean value of the first spectrum is less than the mean value of the second spectrum.

2. The method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T test according to claim 1, characterized in that, The hydrocarbon characteristic absorption band is the band corresponding to the absorption frequency of the CH bond vibration of hydrocarbon substances, and the reference band is the weak absorption band of ground objects.

3. The method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test according to claim 2, characterized in that, The characteristic absorption band of the hydrocarbons is the band within the wavelength range of 1700nm-1780nm; the reference band is the band within the wavelength range of 1560nm-1640nm.

4. The method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T test according to claim 3, characterized in that, The independent samples T-test of the spectral values ​​of the difference spectrum within the characteristic absorption band of the hydrocarbon and within the reference band includes: Calculate the first spectral mean, first spectral variance, and first number of data points of the difference spectrum within the characteristic absorption band of the hydrocarbon; Calculate the second spectral mean, second spectral variance, and second number of data points of the difference spectrum within the reference band; Based on the first spectral mean, the first spectral variance, and the first number of data points, and the second spectral mean, the second spectral variance, and the second number of data points, calculate... t Statistics.

5. The method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T test according to claim 4, characterized in that, The t The formula for calculating the statistic is as follows: ； in, t Indicates the t Statistic, This represents the mean value of the first spectrum. This represents the variance of the first spectrum. This indicates the number of the first data points; This represents the mean of the second spectrum. This represents the variance of the second spectrum. This indicates the number of the second data points.

6. The method for detecting hydrocarbon pollution by coupling spectral difference subtraction and characteristic T-test according to claim 1, characterized in that, Both the target near-infrared spectral data and the background near-infrared spectral data satisfy the following requirements: the spectral range covers 1100nm-2400nm; and the spectral resolution is not less than 12nm.

7. A hydrocarbon pollution detection device coupled with spectral difference subtraction and characteristic T-test, characterized in that, include: The acquisition unit is used to acquire the target near-infrared spectral data of the area to be detected, and determine the corresponding background near-infrared spectral data according to the land cover type of the area to be detected. The background near-infrared spectral data is the reference spectral data of the same land cover as the target to be detected and not contaminated by hydrocarbons. The processing unit is used to perform a difference subtraction process on the target near-infrared spectral data and the background near-infrared spectral data to generate a difference spectrum; The testing unit is used to select a hydrocarbon characteristic absorption band and a reference band in the difference spectrum, and to perform an independent samples T-test on the spectral values ​​of the difference spectrum in the hydrocarbon characteristic absorption band and the spectral values ​​in the reference band to obtain the test results; The reference band is outside the characteristic absorption band of the hydrocarbons; the test results include... t Statistic, the t The statistic is used to measure the significance of the difference in mean values ​​between the difference spectrum and the reference spectrum in the characteristic absorption band of hydrocarbons. Determining unit, used to compare the t The statistical measure is compared with a preset significance threshold, and the first spectral mean of the difference spectrum within the hydrocarbon characteristic absorption band is compared with the second spectral mean of the difference spectrum within the reference band. If the following conditions are met simultaneously, it is determined that hydrocarbon pollution exists in the area to be detected: t The absolute value of the statistic is not less than the significance threshold; the mean of the first spectrum is less than 0; the mean of the first spectrum is less than the mean of the second spectrum.

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