VLF-MF lightning electromagnetic wave identification method, system, medium and equipment
By combining time-domain and frequency-domain similarity calculation methods, the waveform distortion problem in long-distance lightning electromagnetic wave identification was solved, achieving high accuracy and high efficiency in lightning electromagnetic wave identification.
Patent Information
- Application Number
- CN202511800380.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-02-27
AI Technical Summary
Existing VLF-MF lightning electromagnetic wave classification technology is affected by the Earth's surface and ionosphere during long-distance propagation, leading to waveform distortion and misjudgment, making it difficult to effectively identify different types of lightning electromagnetic waves.
A method combining time-domain and frequency-domain similarity is adopted to identify the lightning waveform type by calculating the time-frequency fusion similarity between the target lightning electromagnetic wave and a preset waveform library. This includes steps such as wavelet denoising, window function processing, and fast Fourier transform.
It improves the accuracy and robustness of lightning electromagnetic wave identification, and can effectively identify lightning waveforms under different conditions, thus improving the identification accuracy and efficiency.
Smart Images
Figure CN121580133A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of lightning protection of power systems, and in particular to a VLF-MF lightning electromagnetic wave identification method, system, medium and device. BACKGROUND
[0002] As a violent atmospheric discharge phenomenon in nature, lightning is accompanied by a violent burst of wideband electromagnetic radiation. Different discharge stages contain unique physical mechanisms and radiation characteristics: whether it is the high-energy transient burst of ground flash return stroke (RS), the pulse sequence of initial breakdown in the cloud (PB), or the extremely fast change of bipolar narrow pulse (NBE) and the ordinary cloud flash (IC) process, different VLF-MF lightning electromagnetic wave types have different waveform characteristics in the propagation process.
[0003] However, the existing VLF-MF lightning electromagnetic wave classification technology faces severe challenges in practical application. Traditional methods mainly rely on the extraction of time-domain feature parameters, such as pulse rise time, half-peak width, zero-crossing time, and amplitude ratio. This method is still effective under close observation, but it is extremely fragile in long-distance propagation situations. When electromagnetic waves propagate in the Earth-ionosphere waveguide, they are affected by the skin effect caused by the finite conductivity of the earth and the multipath effect of ionospheric reflection. The high-frequency component is significantly attenuated, resulting in irreversible attenuation and distortion of the waveform. This propagation effect directly causes the time-domain parameters to shift: for example, the waveform of the ground flash return stroke (RS) at a long distance is often widened, and its steepness is reduced, making it easily confused with some wide-pulse cloud flashes (IC). Simply relying on time-domain threshold determination is prone to misjudgment. Although some existing research has introduced frequency spectrum analysis, it is often used independently and lacks effective combination with time-domain microscopic waveform details, making it difficult to form complementary advantages. SUMMARY
[0004] Therefore, it is necessary to propose a VLF-MF lightning electromagnetic wave identification method, system, medium and device to solve the above problems.
[0005] A VLF-MF lightning electromagnetic wave identification method, the method comprising: Obtaining a target VLF-MF lightning electromagnetic wave.
[0006] Respectively calculating the time-domain similarity and frequency-domain similarity of the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library.
[0007] According to the time-domain similarity and frequency-domain similarity, determining the time-frequency fusion similarity of the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library.
[0008] The matching degree between the time-frequency fusion similarity and the preset threshold is determined, and the lightning waveform type of the target VLF-MF lightning electromagnetic wave is identified by the matching degree.
[0009] Specifically, calculating the time-domain similarity and frequency-domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library includes: Extract the main energy segment of the VLF-MF lightning electromagnetic wave.
[0010] according to Calculate the time-domain similarity between the main energy segment and the current lightning electromagnetic wave in the preset waveform library, where, For temporal similarity, The normalized cross-correlation calculation value, , The amplitude of the main energy segment of the VLF-MF lightning electromagnetic wave at the nth sampling point. The current lightning electromagnetic wave in the preset waveform library is at the [number]th [waveform] . The amplitude of each sampling point Sampling frequency, For cross-correlation calculation values, This is a time delay variable.
[0011] The target VLF-MF lightning electromagnetic wave is converted into a spectral vector using a fast Fourier transform.
[0012] according to Calculate the frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, where, For frequency domain similarity, X is the spectral vector of the VLF-MF lightning electromagnetic wave, and Y is the frequency domain similarity. i The frequency spectrum vector of the current lightning electromagnetic wave in the preset waveform library. and Let L2 be the norm of the spectrum vector.
[0013] Specifically, determining the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library based on the time-domain similarity and frequency-domain similarity includes: according to Determine the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, wherein, For time-frequency fusion similarity, As weight, For temporal similarity, For frequency domain similarity.
[0014] The determining the matching degree of the time-frequency fusion similarity and the preset threshold value specifically comprises: According to The determining the matching degree of the time-frequency fusion similarity and the preset threshold value specifically comprises: The matching degree is calculated, The time-frequency fusion similarity is, The preset threshold value is.
[0015] The determining the matching degree of the time-frequency fusion similarity and the preset threshold value specifically comprises: The fault tolerance value is determined.
[0016] When the matching degree is greater than the fault tolerance value, the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the next lightning electromagnetic wave in the preset waveform library is calculated.
[0017] When the matching degree is less than or equal to the fault tolerance value, the lightning waveform type of the current lightning electromagnetic wave in the preset waveform library is determined as the lightning waveform type of the target VLF-MF lightning electromagnetic wave.
[0018] The determining the fault tolerance value specifically comprises: According to The fault tolerance value is determined, wherein, The fault tolerance value is, The preset threshold value is.
[0019] Before the calculating the time-domain similarity and the frequency-domain similarity of the target VLF-MF lightning electromagnetic wave respectively, the method further comprises: The target VLF-MF lightning electromagnetic wave is sequentially subjected to wavelet denoising processing and window function processing.
[0020] A VLF-MF lightning electromagnetic wave identification system, the system comprising: An acquisition module is configured to acquire a target VLF-MF lightning electromagnetic wave.
[0021] A time-domain similarity and frequency-domain similarity determination module is configured to calculate a time-domain similarity and a frequency-domain similarity of the target VLF-MF lightning electromagnetic wave and a current lightning electromagnetic wave in a preset waveform library respectively.
[0022] A time-frequency fusion similarity determination module is configured to determine a time-frequency fusion similarity of the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library according to the time-domain similarity and the frequency-domain similarity.
[0023] A lightning waveform type identification module is configured to determine a matching degree of the time-frequency fusion similarity and a preset threshold value, and identify a lightning waveform type of the target VLF-MF lightning electromagnetic wave through the matching degree.
[0024] A computer readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the steps of the method described above.
[0025] A computer device comprises a memory and a processor, the memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the method described above.
[0026] The embodiment of the present application has the following beneficial effects: The present application provides a way of directly measuring the similarity between waveforms in the time domain by calculating the time domain similarity, effectively capturing the characteristics of waveforms in the time domain, and improving the recognition accuracy; a method of measuring the similarity between waveforms in the frequency domain is provided by calculating the frequency domain similarity, which can capture the frequency composition characteristics of the waveforms, further improving the recognition accuracy. Moreover, the time-frequency fusion similarity is calculated by combining the time domain similarity and the frequency domain similarity, which can comprehensively capture the space-time characteristics of the waveforms to comprehensively evaluate the waveforms, improve the accuracy and robustness of the recognition, and ensure effective recognition under different conditions. By combining the time domain waveform details and the frequency energy distribution characteristics, the recognition accuracy and efficiency of VLF-MF lightning electromagnetic waves are significantly improved. BRIEF DESCRIPTION OF DRAWINGS
[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0028] Among them: Figure 1 A flowchart of an embodiment of a VLF-MF lightning electromagnetic wave recognition method provided by the present application; Figure 2 A time sequence waveform of a target VLF-MF lightning electromagnetic wave provided by the present application; Figure 3 A time sequence waveform of a preprocessed target VLF-MF lightning electromagnetic wave provided by the present application; Figure 4 A flowchart of an embodiment of a VLF-MF lightning electromagnetic wave recognition method provided by the present application; Figure 5 A structural schematic diagram of an embodiment of a VLF-MF lightning electromagnetic wave recognition system provided by the present application; Figure 6 A structural schematic diagram of an embodiment of a device provided by the present application; Figure 7 Structure diagram of an embodiment of the medium provided by the present application. DETAILED DESCRIPTION
[0029] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.
[0030] As shown in Figure 1 , Figure 1 Flowchart of an embodiment of the VLF-MF lightning electromagnetic wave identification method provided by the present application. The VLF-MF lightning electromagnetic wave identification method comprises the following steps: S101: Obtain a target VLF-MF lightning electromagnetic wave.
[0031] Exemplarily, a VLF-MF lightning electromagnetic wave with a sampling rate of 10 MHz and a sampling time window of 2 ms is obtained through a lightning monitoring system, and the time sequence waveform of the lightning electromagnetic wave is as shown in Figure 2 , Figure 2 The time sequence waveform of the target VLF-MF lightning electromagnetic wave provided by the present application. Further, the time sequence waveform of the target VLF-MF lightning electromagnetic wave is preprocessed, including noise reduction and window function processing, the noise reduction adopts wavelet noise reduction, and the window function processing adopts a Hann Window window function, and the processing result is as shown in Figure 3 , Figure 3 The time sequence waveform of the target VLF-MF lightning electromagnetic wave provided by the present application after preprocessing.
[0032] S102: Calculate the time domain similarity and the frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, respectively.
[0033] Exemplarily, the obtained target VLF-MF lightning electromagnetic wave is subjected to automatic main energy segment processing, and the main energy segment of the VLF-MF lightning electromagnetic wave is extracted. The time domain similarity between the main energy segment and the current lightning electromagnetic wave in the preset waveform library is calculated according to the formula as shown below: ; Among them, is the time domain similarity, is the normalized cross-correlation calculation value.
[0034] ; Among them, is the amplitude of the main energy segment of the VLF-MF lightning electromagnetic wave at the nth sampling point, is the amplitude of the current lightning electromagnetic wave in the preset waveform library at the nth sampling point, is the sampling frequency, is the cross-correlation calculation value, is the time delay variable; wherein, is the cross-correlation calculation value, is the time delay variable, indicating the time offset of the waveform relative to the waveform x, .
[0035] It should be noted that the value range of the time delay variable is 0.1-0.25 ms, and the value is determined according to two principles: (1) Only fine adjustment of alignment is allowed in the same sub-pulse; (2) It needs to cover the normal time drift of the main peak of the same type of lightning electromagnetic wave.
[0036] In addition, the target VLF-MF lightning electromagnetic wave is converted into a frequency spectrum vector by fast Fourier transform; and the frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library is calculated according to the formula as shown below: . wherein, is the frequency domain similarity, X is the frequency spectrum vector of the VLF-MF lightning electromagnetic wave, Yi is the frequency spectrum vector of the current lightning electromagnetic wave in the preset waveform library, and is the L2 norm of the frequency spectrum vector, and the calculation formula is: . .
[0037] It should be noted that the preset waveform library includes four types of typical VLF-MF lightning electromagnetic waves: ground flash, initial breakdown pulse, narrow bipolar pulse, and cloud flash, and the sampling frequency f is not less than 10 MHz.
[0038] S103: Determine the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library according to the time domain similarity and the frequency domain similarity.
[0039] Exemplarily, the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library is determined according to the formula as shown below: . wherein, is a time-frequency fusion similarity, is a weight and k [0, 1], is a time domain similarity, is a frequency domain similarity.
[0040] It should be noted that the weight The value range is 0.3-0.7, and is selected according to the stability of the time domain similarity and the frequency domain similarity of various lightning electromagnetic waveforms. The greater the weight value is, the better the stability is.
[0041] S104: Determine the matching degree of the time-frequency fusion similarity and the preset threshold value, and identify the lightning waveform type of the target VLF-MF lightning electromagnetic wave through the matching degree.
[0042] Exemplarily, the matching degree of the time-frequency fusion similarity and the preset threshold value is determined according to the formula as shown below: ; Wherein, is a matching degree calculation value, is a time-frequency fusion similarity, is a preset threshold value, The selection range is 0.90-0.95, and the preset threshold value can be dynamically adjusted according to historical samples or test set experimental results.
[0043] And the fault tolerance value is determined according to the formula as shown below: ; Wherein, is a fault tolerance value, is a preset threshold value.
[0044] Further, when the matching degree is greater than the fault tolerance value, the time-frequency fusion similarity of the target VLF-MF lightning electromagnetic wave and the next lightning electromagnetic wave in the preset waveform library is calculated; when the matching degree is less than or equal to the fault tolerance value, it is determined that the lightning waveform type of the current lightning electromagnetic wave in the preset waveform library is the lightning waveform type of the target VLF-MF lightning electromagnetic wave.
[0045] It can be known from the above description that the application provides a way of directly measuring the similarity between waveforms in the time domain by calculating the time domain similarity, effectively captures the features of waveforms in the time domain, and improves the recognition accuracy; a method of measuring the similarity between waveforms in the frequency domain is provided by calculating the frequency domain similarity, the frequency composition features of waveforms can be captured, and the recognition accuracy is further improved. In addition, the time-frequency fusion similarity is calculated by combining the time domain similarity and the frequency domain similarity, the space-time features of waveforms can be comprehensively captured to comprehensively evaluate the waveforms, the accuracy and robustness of recognition are improved, and effective recognition can be ensured under different conditions. By combining the time domain waveform details and the frequency energy distribution features, the recognition accuracy and efficiency of VLF-MF lightning electromagnetic waves are significantly improved.
[0046] As shown in Figure 4 , Figure 4 The flowchart of an embodiment of a VLF-MF lightning electromagnetic wave recognition method provided by the application is shown. The VLF-MF lightning electromagnetic wave recognition method comprises the following steps: S201: Obtain a target VLF-MF lightning electromagnetic wave.
[0047] Exemplarily, a preset waveform library is constructed in advance, the preset waveform library contains four types of typical VLF-MF lightning electromagnetic waves, i.e., ground flash return stroke, initial breakdown pulse, narrow bipolar pulse and cloud flash, each type of waveform contains 4000 data, the data sampling rate is f=10 MHz, the time resolution is 0.1 μs, the sampling time window is 2 ms, the sampling point number is 20000, and the sampling time interval is 0.1 μs.
[0048] Further, the VLF-MF lightning electromagnetic wave with a sampling rate of 10 MHz and a sampling time window of 2 ms is obtained through a lightning monitoring system, and the waveform is subjected to noise reduction and window function processing.
[0049] S202: Calculate the time domain similarity and the frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, respectively.
[0050] Exemplarily, the obtained lightning waveform is subjected to automatic main energy segment processing, the main energy segment is extracted, and then the time domain similarity between the waveform and the ground flash return stroke in the preset waveform library is calculated according to the following formula:
[0051] Among them, According to the following formula: ; Among them, According to the following formula, τ=0.2 ms: ; Among them, For temporal similarity, The normalized cross-correlation calculation value, This represents the amplitude of the main energy segment of the VLF-MF lightning electromagnetic wave at the nth sampling point. The current lightning electromagnetic wave in the preset waveform library is at the [number]th [waveform] . The amplitude of each sampling point Sampling frequency, For cross-correlation calculation values, This is a time delay variable.
[0052] The calculated time-domain similarity with the RS wave in the waveform library is: .
[0053] Simultaneously, a Fast Fourier Transform (FFT) is performed on the preprocessed VLF-MF lightning electromagnetic wave to obtain a single-sided amplitude spectrum of 3kHz-3MHz. The amplitude values of each frequency point in the single-sided amplitude spectrum are arranged in frequency order to form a one-dimensional numerical vector (for example, if the single-sided amplitude spectrum has N frequency points, the spectrum vector is an N-dimensional column vector or row vector). The frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the ground flash return stroke in the preset waveform library is then calculated. ; in, and The L2 norm of the spectrum vector is calculated using the following formula: ; ; The final calculated frequency domain similarity with the ground flash return stroke in the waveform library is: .
[0054] S203: Determine the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library based on time-domain similarity and frequency-domain similarity.
[0055] For example, the time-frequency fusion similarity between the acquired lightning waveform and the ground flash return stroke in the waveform library is calculated using the following formula: ; in, Let k be the weight and take k=0.4.
[0056] The calculated time-frequency fusion similarity with the ground flash return stroke in the waveform library is: .
[0057] S204: Determine the matching degree between the time-frequency fusion similarity and the preset threshold.
[0058] For example, the time-frequency fusion similarity is calculated according to the formula shown below. With preset threshold The matching degree is calculated. ; The matching degree is calculated. The matching degree is calculated. .
[0059] S205: Determine the fault tolerance value.
[0060] Exemplarily, the fault tolerance value is determined according to the formula as shown below: ; The fault tolerance value is calculated , 0.1 is selected.
[0061] S206: When the matching degree is greater than the fault tolerance value, the time-frequency fusion similarity of the target VLF-MF lightning electromagnetic wave and the next lightning electromagnetic wave in the preset waveform library is calculated.
[0062] S207: When the matching degree is less than or equal to the fault tolerance value, it is determined that the lightning waveform type of the current lightning electromagnetic wave in the preset waveform library is the lightning waveform type of the target VLF-MF lightning electromagnetic wave.
[0063] Exemplarily, when the matching degree is greater than the fault tolerance value , the result is not matched, and the similarity of the target VLF-MF lightning electromagnetic wave and the next lightning electromagnetic wave in the waveform library is continuously calculated; when is less than or equal to the fault tolerance value , the recognition result is obtained, and the recognition result is: the target VLF-MF lightning electromagnetic wave is a ground flash return stroke electromagnetic wave.
[0064] As can be known from the above description, the present application combines time domain and frequency domain analysis to construct a dual-path similarity calculation framework. The complementarity and confirmation of time-frequency characteristics form a more three-dimensional and more complete digital image of the electromagnetic wave, which fundamentally improves the discrimination and robustness of the feature representation and lays a solid foundation for high-precision classification.
[0065] Moreover, the classification result of the present application is based on clear and quantifiable similarity calculation, and the specific similarity numerical value of the target VLF-MF lightning electromagnetic wave and each waveform in the preset waveform library in the time domain and the frequency domain is obtained. It is convenient for R&D and operation personnel to understand the judgment basis of the model, allows expert knowledge to intervene, and through the adjustment of the weight coefficient, flexible and guided fine-tuning can be carried out according to the lightning activity characteristics of different regions and different seasons, which greatly improves the practicability and adaptability of the method.
[0066] As Figure 5 described, Figure 5This is a schematic diagram of an embodiment of a VLF-MF lightning electromagnetic wave identification system provided by the present invention. A VLF-MF lightning electromagnetic wave identification system 10, the system includes: Acquisition module 11 is used to acquire the target VLF-MF lightning electromagnetic wave.
[0067] The time-domain similarity and frequency-domain similarity determination module 12 is used to calculate the time-domain similarity and frequency-domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, respectively.
[0068] The time-frequency fusion similarity determination module 13 is used to determine the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library based on the time-domain similarity and frequency-domain similarity.
[0069] The lightning waveform type identification module 14 is used to determine the matching degree between the time-frequency fusion similarity and the preset threshold, and to identify the lightning waveform type of the target VLF-MF lightning electromagnetic wave through the matching degree.
[0070] For example, in the acquisition module 11, the target VLF-MF lightning electromagnetic wave is acquired. In the time-domain similarity and frequency-domain similarity determination module 12, the main energy segment of the VLF-MF lightning electromagnetic wave is extracted; the time-domain similarity between the main energy segment and the current lightning electromagnetic wave in the preset waveform library is calculated according to the formula shown: ; in, For temporal similarity, The normalized cross-correlation calculation value, ; in, This represents the amplitude of the main energy segment of the VLF-MF lightning electromagnetic wave at the nth sampling point. The current lightning electromagnetic wave in the preset waveform library is at the [number]th [waveform] . The amplitude of each sampling point Sampling frequency, For cross-correlation calculation values, This is a time delay variable.
[0071] Simultaneously, the target VLF-MF lightning electromagnetic wave is converted into a spectral vector using a Fast Fourier Transform; the frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library is calculated according to the following formula: ; in, For frequency domain similarity, X is the spectral vector of the VLF-MF lightning electromagnetic wave, and Yi is the spectral vector of the current lightning electromagnetic wave in the preset waveform library. and Let L2 be the norm of the spectrum vector.
[0072] In the time-frequency fusion similarity determination module 13, the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library is determined according to the following formula: ; in, For time-frequency fusion similarity, As weight, For temporal similarity, For frequency domain similarity.
[0073] In the lightning waveform type identification module 14, the matching degree between the time-frequency fusion similarity and the preset threshold is determined, and the fault tolerance value is determined. When the matching degree is greater than the fault tolerance value, the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the next lightning electromagnetic wave in the preset waveform library is calculated. When the matching degree is less than or equal to the fault tolerance value, the current lightning electromagnetic wave in the preset waveform library is determined to be the corresponding lightning waveform type of the target VLF-MF lightning electromagnetic wave.
[0074] like Figure 6 As shown, Figure 6 This is a schematic diagram of an embodiment of the device provided by the present invention. The device 20 includes a memory 21 and a processor 22. The memory 21 stores a computer program, and the processor 22 executes the computer program during operation to achieve, for example... Figure 1 and Figure 4 The method shown.
[0075] The specific technical details of the VLF-MF lightning electromagnetic wave identification method implemented by the above-mentioned device 20 when executing the computer program have been discussed in detail in the above method steps, so they will not be repeated here.
[0076] like Figure 7 As shown, Figure 7 This is a schematic diagram of the structure of an embodiment of the medium provided by the present invention. The medium 30 stores at least one computer program 31, which is executed by the processor 22 to perform the following... Figure 1 and Figure 4 The method shown is detailed above and will not be repeated here. In one embodiment, the medium 30 can be a storage chip, hard disk, portable hard disk, USB flash drive, optical disk, or other read / write storage device, or even a server, etc.
[0077] Furthermore, the processes depicted in the accompanying drawings do not necessarily have to be performed in the specific or sequential order shown to achieve the desired result. In some implementations, multitasking and parallel processing are possible or may be advantageous.
[0078] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, for the device, equipment, and non-volatile computer-readable storage medium embodiments, since they are basically similar to the method embodiments, they are described more simply, and the relevant parts can be referred to the part of the method embodiments.
[0079] The device, equipment, non-volatile computer-readable storage medium, and method provided by the embodiments of the specification are corresponding, and therefore, the device, equipment, and non-volatile computer-readable storage medium also have similar beneficial technical effects as the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the corresponding device, equipment, and non-volatile computer-readable storage medium will not be described here.
[0080] The system, device, module, or unit illustrated in the above embodiments can be specifically implemented by a computer chip or entity, or by a product with certain functions. A typical implementation device is a computer. Specifically, the computer may, for example, be a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.
[0081] For the convenience of description, the above device is described as various units divided by functions. Of course, the functions of each unit can be implemented in the same or multiple software and / or hardware in the implementation of the specification. Those skilled in the art should understand that the embodiments of the specification can be provided as a method, a system, or a computer program product. Therefore, the embodiments of the specification can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the specification can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.
[0082] The specification is described with reference to flowcharts and / or block diagrams according to the method, device (system), and computer program product of the embodiments of the specification. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a machine that implements the functions described in the flowcharts and / or block diagrams.Figure 1 one or more processes and / or blocks Figure 1 means for performing the function specified by the block or blocks.
[0083] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the Figure 1 one or more processes and / or blocks Figure 1 means for performing the function specified by the block or blocks.
[0084] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the Figure 1 one or more processes and / or blocks Figure 1 means for performing the function specified by the block or blocks.
[0085] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.
[0086] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. A
[0087] Computer-readable media includes permanent and non-permanent, moveable and non- moveable media that can be implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disks (DVDs) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that is accessible to a computing device. According to the definitions provided herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.
[0088] It is also to be noted that the terms "comprising", "including", and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.
[0089] The specification can be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The specification can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules can be located in both local and remote computer storage media including memory storage devices.
[0090] The various embodiments in the specification are described in progressive manner, and the same or similar parts between the embodiments can be mutually referred to. Each embodiment focuses on the difference from other embodiments. In particular, the system embodiments are described in a relatively simple manner because they are substantially similar to the method embodiments, and the relevant parts can be referred to the description of the method embodiments.
[0091] The above disclosure only represents the preferred embodiments of the present application, and of course cannot limit the scope of the present application. Therefore, any equivalent changes made according to the claims of the present application are still within the scope of the present application.
Claims
1. A VLF-MF lightning electromagnetic wave identification method, characterized in that, The method includes: Acquire the target VLF-MF lightning electromagnetic wave; Calculate the time-domain similarity and frequency-domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, respectively; The time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library is determined based on the time-domain similarity and frequency-domain similarity. The matching degree between the time-frequency fusion similarity and the preset threshold is determined, and the lightning waveform type of the target VLF-MF lightning electromagnetic wave is identified by the matching degree.
2. The VLF-MF lightning electromagnetic wave identification method according to claim 1, characterized in that, The calculation of the time-domain similarity and frequency-domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library specifically includes: Extract the main energy segment of the VLF-MF lightning electromagnetic wave; according to Calculate the time-domain similarity between the main energy segment and the current lightning electromagnetic wave in the preset waveform library, where, For temporal similarity, The normalized cross-correlation calculation value, , The amplitude of the main energy segment of the VLF-MF lightning electromagnetic wave at the nth sampling point. The current lightning electromagnetic wave in the preset waveform library is at the [number]th [waveform] . The amplitude of each sampling point Sampling frequency, For cross-correlation calculation values, For time delay variables; The target VLF-MF lightning electromagnetic wave is converted into a spectral vector using a fast Fourier transform. according to Calculate the frequency domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, where, For frequency domain similarity, X is the spectral vector of the VLF-MF lightning electromagnetic wave, and Y is the frequency domain similarity. i The frequency spectrum vector of the current lightning electromagnetic wave in the preset waveform library. and Let L2 be the norm of the spectrum vector.
3. The VLF-MF lightning electromagnetic wave identification method according to claim 2, characterized in that, The step of determining the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library based on the time-domain similarity and frequency-domain similarity specifically includes: according to Determine the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, wherein, For time-frequency fusion similarity, As weight, For temporal similarity, For frequency domain similarity.
4. The VLF-MF lightning electromagnetic wave identification method according to claim 3, characterized in that, Determining the matching degree between the time-frequency fusion similarity and the preset threshold specifically includes: according to Determine the matching degree between the time-frequency fusion similarity and a preset threshold, wherein, This is the calculated matching score. For time-frequency fusion similarity, This is a preset threshold.
5. The VLF-MF lightning electromagnetic wave identification method according to claim 1, characterized in that, The step of identifying the lightning waveform type of the target VLF-MF lightning electromagnetic wave through the matching degree specifically includes: Determine the fault tolerance value; When the matching degree is greater than the fault tolerance value, the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the next lightning electromagnetic wave in the preset waveform library is calculated. When the matching degree is less than or equal to the fault tolerance value, the lightning waveform type of the current lightning electromagnetic wave in the preset waveform library is determined to be the lightning waveform type of the target VLF-MF lightning electromagnetic wave.
6. The VLF-MF lightning electromagnetic wave identification method according to claim 5, characterized in that, The determination of the fault tolerance value specifically includes: according to Determine the fault tolerance value, where, This is the fault tolerance value. This is a preset threshold.
7. The VLF-MF lightning electromagnetic wave identification method according to claim 1, characterized in that, Before calculating the time-domain and frequency-domain similarity of the target VLF-MF lightning electromagnetic wave, the method further includes: The target VLF-MF lightning electromagnetic wave is subjected to wavelet denoising and window function processing in sequence.
8. A VLF-MF lightning electromagnetic wave identification system, characterized in that, The system includes: The acquisition module is used to acquire the target VLF-MF lightning electromagnetic wave; The time-domain similarity and frequency-domain similarity determination module is used to calculate the time-domain similarity and frequency-domain similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library, respectively. The time-frequency fusion similarity determination module is used to determine the time-frequency fusion similarity between the target VLF-MF lightning electromagnetic wave and the current lightning electromagnetic wave in the preset waveform library based on the time-domain similarity and frequency-domain similarity. The lightning waveform type identification module is used to determine the matching degree between the time-frequency fusion similarity and the preset threshold, and to identify the lightning waveform type of the target VLF-MF lightning electromagnetic wave through the matching degree.
9. A computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method as claimed in any one of claims 1 to 7.
10. A computer device comprising a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the method as claimed in any one of claims 1 to 7.