Water area oil spill detection method and water area oil spill detection device

Abstract

The invention discloses a water area oil spill detection method and a water area oil spill detection device. The method comprises the following steps: collecting a reflected light signal reflected by a target water area based on an incident detection signal; generating a digital signal time sequence matched with the spectral information according to the spectral information of the reflected light signal; carrying out discrete transformation on the digital signal time sequence by utilizing a wavelet function to obtain a coefficient matrix, carrying out noise reduction processing to obtain a noise reduction matrix, and reconstructing and generating a noise reduction signal time sequence according to the noise reduction matrix; separating a background signal corresponding to the target water area and a target signal corresponding to a surface substance of the target water area from the noise reduction signal time sequence; and identifying the surface substance type of the target water area according to the background signal and the target signal to determine the oil spill information of the target water area. The method comprises the following steps of: discretely transforming a digital signal time sequence into a coefficient matrix by using a wavelet function, reducing noise of the coefficient matrix, and reducing to obtain a smooth, clear and low-noise noise reduction signal time sequence, so as to accurately identify the oil spill condition by using the noise reduction signal time sequence.

Description

Technical Field

[0001] The present application relates to the field of environmental monitoring, and in particular to a method and device for detecting oil spills in water areas. Background Art

[0002] At present, most of the crude oil extraction, transportation and processing are carried out in the ocean or near-shore areas. Since the ocean and near-shore areas are easily affected by severe weather such as typhoons, leakage of oily hazardous chemicals (i.e. oil spills) may occur, which will not only threaten the safety of people’s lives and property, but also cause serious environmental pollution.

[0003] In order to detect oil spills in the ocean or nearshore areas, especially in the operation areas and production areas of petrochemical products, it is necessary to conduct oil spill detection in the preset waters and feed the detection results back to the monitoring platform. A common detection method is to use ultraviolet fluorescence induction to detect oily hazardous chemicals on the water surface.

[0004] However, given the complexity and variability of the marine environment, not only a variety of natural light sources including sunlight, moonlight and atmospheric scattered light may become interference factors, but the waves themselves will also cause a certain interference to the reflected light, resulting in inaccurate reading of the fluorescent signal of the sea surface oil film and low detection efficiency. Summary of the invention

[0005] The present application provides a method and a device for detecting oil spills in water areas, aiming to improve the accuracy and efficiency of oil spill detection in water areas.

[0006] In a first aspect, the present application provides a method for detecting oil spills in waters, comprising:

[0007] Collecting reflected light signals from the target water area, where the reflected light signals are light signals reflected from the target water area based on the incident detection signals;

[0008] generating a digital signal time series matching the spectral information according to the spectral information of the reflected light signal;

[0009] Using a preset wavelet function to perform discrete transformation on the digital signal time series to obtain a coefficient matrix, wherein the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies;

[0010] The coefficient matrix is ​​subjected to denoising to obtain a denoising matrix, and a denoising signal time series is generated based on the denoising matrix reconstruction;

[0011] Separating the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area from the noise reduction signal time series;

[0012] The surface material type of the target water area is identified according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type.

[0013] In some embodiments, the method further includes outputting a detection signal to the target water area according to a target operation mode, the target operation mode including one of a single operation mode and a continuous operation mode;

[0014] Among them, outputting a detection signal to the target water area according to the target operation mode includes:

[0015] In the single operation mode, the detection signal is output to the target water area in response to the output command;

[0016] In the continuous operation mode, a detection signal is output to the target water area when the preset detection signal output conditions are met. The detection signal output conditions include: when a start instruction corresponding to the continuous operation mode is received, or after the process of determining the oil spill information of the target water area based on the reflected light signal corresponding to the previous detection signal is completed.

[0017] In some embodiments, collecting reflected light signals from the target water area includes:

[0018] Acquiring ambient temperature information of the photodetector, and determining a target operating voltage of the photodetector according to the ambient temperature information;

[0019] The voltage input to the photodetector is adjusted according to the target operating voltage, so that the photodetector collects the reflected light signal based on the target operating voltage.

[0020] In some embodiments, generating a digital signal time series matching the spectral information according to the spectral information of the reflected light signal includes:

[0021] Filtering and amplifying the reflected light signal to obtain an optimized light signal;

[0022] The optimized optical signal is sampled according to a preset sampling period to obtain multiple groups of time-discrete voltage data;

[0023] Multiple sets of voltage data are combined into a digital signal time series based on the time order of time nodes.

[0024] In some implementations, using a preset wavelet function to perform discrete transformation on a digital signal time series includes:

[0025] A convolution operation is performed on the digital signal time series using a preset wavelet function to obtain a plurality of wavelet coefficients, and different wavelet coefficients are used to characterize the signal characteristics of the reflected light signal at different scales and / or different frequencies;

[0026] A coefficient matrix is ​​constructed according to the wavelet coefficients, wherein the elements in the coefficient matrix are the wavelet coefficients.

[0027] In some implementations, performing denoising on the coefficient matrix to obtain a denoised matrix includes:

[0028] Extracting elements in the coefficient matrix to obtain multiple wavelet coefficients;

[0029] Determine a filtering threshold according to the plurality of wavelet coefficients, and screen out abnormal coefficients from the plurality of wavelet coefficients based on the filtering threshold;

[0030] The abnormal coefficients in the coefficient matrix are set to zero to obtain the denoised matrix.

[0031] In some embodiments, generating a denoised signal time series according to the denoising matrix reconstruction includes:

[0032] The denoising matrix reconstructs the denoised signal time series layer by layer through upsampling, filtering and addition operations.

[0033] In some embodiments, the detection signal is a periodically flashing light signal, and separating the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area from the noise reduction signal time series includes:

[0034] Construct a corresponding signal strength curve according to the noise reduction signal time series, and identify the troughs and peaks in the signal strength curve;

[0035] The background signal and the target signal are separated from the noise reduction signal time series according to the trough and the peak, wherein the intensity amplitude of the curve trough corresponds to the amplitude of the background signal, and the intensity amplitude of the curve peak corresponds to the amplitude of the target signal.

[0036] In some embodiments, identifying the surface material type of the target water area according to the background signal and the target signal includes:

[0037] Calculate the signal difference at different time nodes according to the background signal and the target signal to generate a signal difference sequence;

[0038] Calculate the abnormal probability corresponding to each time node according to the signal difference sequence, and select the nodes to be evaluated from the time nodes according to the abnormal probability;

[0039] When the node to be evaluated meets the preset abnormal judgment condition, the surface material type is determined to be an oily substance;

[0040] Among them, the preset abnormal judgment conditions include:

[0041] In the adjacent time interval of the node to be evaluated, the fluctuation of the background signal is less than the fluctuation threshold; and the difference judgment ratio between the target signal and the background signal is greater than the ratio threshold.

[0042] In some embodiments, after determining the oil spill information of the target waters according to the surface material type, the method further includes:

[0043] When it is determined according to the oil spill information that oil spill occurs in the target waters or the extent of oil spill reaches a preset extent, an alarm signal is generated and sent to a preset monitoring terminal;

[0044] The alarm signal at least includes location information corresponding to the oil spill information.

[0045] In a second aspect, the present application also provides a water area oil spill detection device, comprising:

[0046] A light collection module, used to collect reflected light signals from the target water area, where the reflected light signals are light signals reflected from the target water area based on the incident detection signals;

[0047] The control module is connected to the light collection module and is used to generate a digital signal time series that matches the spectral information according to the spectral information of the reflected light signal; the digital signal time series is discretely transformed using a preset wavelet function to obtain a coefficient matrix, and the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies; the coefficient matrix is ​​denoised to obtain a denoised matrix, and a denoised signal time series is generated based on the denoised matrix reconstruction; a background signal corresponding to the target water area and a target signal corresponding to the surface material of the target water area are separated from the denoised signal time series; the surface material type of the target water area is identified according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type.

[0048] In some embodiments, the device further comprises an optical output module electrically connected to the control module, for outputting a detection signal to the target water area according to a target operation mode, wherein the target operation mode comprises one of a single operation mode and a continuous operation mode;

[0049] Wherein, in the single operation mode, the optical output module outputs a detection signal to the target water area in response to the output instruction;

[0050] In the continuous operation mode, the optical output module outputs a detection signal to the target water area when the preset detection signal output conditions are met. The detection signal output conditions include: when a start instruction corresponding to the continuous operation mode is received, or after the process of determining the oil spill information of the target water area based on the reflected light signal corresponding to the previous detection signal is completed.

[0051] In some embodiments, the device further comprises an alarm module, which is used to generate an alarm signal and send the alarm signal to a preset monitoring terminal when it is determined according to the oil spill information that oil spill occurs in the target waters or the extent of the oil spill reaches a preset extent;

[0052] The alarm signal at least includes location information corresponding to the oil spill information.

[0053] The embodiments of the present application provide a method for detecting oil spills in water areas and a device for detecting oil spills in water areas, wherein the method for detecting oil spills in water areas comprises: collecting a reflected light signal of a target water area, wherein the reflected light signal is a light signal reflected by the target water area based on an incident detection signal; generating a digital signal time series matching the spectral information according to the spectral information of the reflected light signal; performing a discrete transformation on the digital signal time series using a preset wavelet function to obtain a coefficient matrix, wherein the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies; performing denoising processing on the coefficient matrix to obtain a denoising matrix, and reconstructing a denoised signal time series according to the denoising matrix; separating a background signal corresponding to the target water area and a target signal corresponding to a surface material of the target water area from the denoised signal time series; identifying a surface material type of the target water area according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type. The present application utilizes wavelet function to discretely transform digital signal time series into coefficient matrix, performs denoising on the coefficient matrix to obtain denoised matrix, and restores the denoised matrix to a smooth, clear and low-noise denoised signal time series, so as to utilize the denoised signal time series to identify the surface material type of the target waters, thereby improving the accuracy of identifying oil spills.

[0054] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and cannot limit the disclosure of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0056] Figure 1 A block diagram of the module structure of an implementation of a water area oil spill detection device provided in an embodiment of the present application;

[0057] Figure 2 A module structure block diagram of another implementation of the water area oil spill detection device provided in an embodiment of the present application;

[0058] Figure 3 A module structure block diagram of another implementation of the water area oil spill detection device provided in an embodiment of the present application;

[0059] Figure 4 A schematic diagram of a step flow of a method for detecting oil spills in waters provided in an embodiment of the present application;

[0060] Figure 5 A schematic diagram of a temperature-voltage control closed loop in a method for detecting oil spills in waters provided in an embodiment of the present application;

[0061] Figure 6 Another schematic diagram of the process flow of the method for detecting oil spills in waters provided in an embodiment of the present application;

[0062] Figure 7 A schematic diagram of a digital signal time series and a noise reduction signal time series in a method for detecting oil spills in waters provided in an embodiment of the present application.

[0063] Reference numerals:

[0064] 1. Water area oil spill detection device; 10. Light collection module; 20. Control module; 30. Light output module; 40. Alarm module. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0066] At present, most of the crude oil extraction, transportation and processing are carried out in the ocean or near-shore areas. Since the ocean and near-shore areas are easily affected by severe weather such as typhoons, leakage of oily hazardous chemicals (i.e. oil spills) may occur, which will not only threaten the safety of people’s lives and property, but also cause serious environmental pollution.

[0067] In order to detect oil spills in the ocean or nearshore areas, especially in the operation areas and production areas of petrochemical products, it is necessary to conduct oil spill detection in the preset waters and feed the detection results back to the monitoring platform. A common detection method is to use ultraviolet fluorescence induction to detect oily hazardous chemicals on the water surface.

[0068] However, given the complexity and variability of the marine environment, not only a variety of natural light sources including sunlight, moonlight and atmospheric scattered light may become interference factors, but the waves themselves will also cause a certain interference to the reflected light, resulting in inaccurate reading of the fluorescent signal of the sea surface oil film and low detection efficiency.

[0069] Based on this, the present application provides a water area oil spill detection method and a water area oil spill detection device, aiming to improve the accuracy and efficiency of water area oil spill detection.

[0070] See also Figure 1 , Figure 1This is a block diagram of the module structure of an implementation scheme of a water area oil spill detection device 1 provided in an embodiment of the present application.

[0071] like Figure 1 As shown, the water area oil spill detection device 1 provided in the present application is described. The water area oil spill detection device 1 at least includes: a light collection module 10 and a control module 20 connected to the light collection module 10 .

[0072] Specifically, the light collection module 10 is used to collect the reflected light signal of the target water area, and the reflected light signal is the light signal reflected by the target water area based on the incident detection signal. The control module 20 is used to perform the following actions: generate a digital signal time series that matches the spectral information according to the spectral information of the reflected light signal; use a preset wavelet function to discretely transform the digital signal time series to obtain a coefficient matrix, and the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies; perform denoising on the coefficient matrix to obtain a denoising matrix, and reconstruct the denoising matrix to generate a denoised signal time series; separate the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area from the denoised signal time series; identify the surface material type of the target water area according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type.

[0073] More specifically, the reflected light signal is generated by the target water area under the stimulation of the incident detection signal, wherein the detection signal includes but is not limited to ultraviolet light or one of other light signals.

[0074] Exemplarily, the light collection module 10 includes a silicon photomultiplier (SiPM).

[0075] It should be understood that the signal characteristics of the reflected light signal are related to the substances floating on the surface of the target water area, especially when oily hazardous chemicals leak in the target water area and there is oil spill floating on the surface of the target water area. The water area oil spill detection device 1 provided in the present application can collect the reflected light signal through the light collection module 10, and the control module 20 analyzes the collected reflected light signal to identify the surface material type of the target water area, thereby determining the oil spill information of the target water area.

[0076] It should also be understood that the detection signal output to the target water area may be provided by the water area oil spill detection device 1 provided in the embodiment of the present application, or may be provided by other devices used in conjunction with the water area oil spill detection device 1.

[0077] See also Figure 2 and 3 , Figure 2 This is a module structure block diagram of another implementation of the water area oil spill detection device 1 provided in an embodiment of the present application, Figure 3Schematic diagram of the detection scenario of the water area oil spill detection device 1 provided in an embodiment of the present application.

[0078] like Figure 2 As shown, in some embodiments, the water area oil spill detection device 1 also includes an optical output module 30 electrically connected to the control module 20, which is used to output a detection signal to the target water area according to the target operation mode, so that the target water area generates a reflected light signal under the excitation of the detection signal. Exemplarily, the detection signal includes but is not limited to ultraviolet light or other light signals.

[0079] Specifically, the target operation mode includes one of a single operation mode and a continuous operation mode. In the single operation mode, the optical output module 30 outputs a detection signal to the target water area in response to an output instruction; in the continuous operation mode, the optical output module 30 outputs a detection signal to the target water area when a preset detection signal output condition is met, and the detection signal output condition includes: when a start instruction corresponding to the continuous operation mode is received, or after the process of determining the oil spill information of the target water area according to the reflected light signal corresponding to the previous detection signal is completed.

[0080] Specifically, the single operation mode means that the light output module 30 outputs only one detection signal after responding to the output instruction, while the continuous operation mode means that the light output module 30 continuously outputs multiple detection signals after responding to the output instruction. Specifically, after the process of determining the oil spill information of the target water area by the reflected light signal corresponding to the previous detection signal is completed, the next detection signal is output, so as to determine the oil spill information of the target water area according to the reflected light signal corresponding to the next detection signal, thereby avoiding mutual interference between different detection signals, and the continuous operation mode can meet the operational requirements of the water area oil spill detection device 1 to continuously monitor the oil spill information.

[0081] like Figure 2 As shown, in some embodiments, the water area oil spill detection device 1 also includes an alarm module 40, which is used to generate an alarm signal and send the alarm signal to a preset monitoring terminal when it is determined that oil spill occurs in the target water area or the degree of oil spill reaches a preset degree based on the oil spill information, wherein the alarm signal includes at least location information corresponding to the oil spill information.

[0082] It should be understood that the oil spill information at least includes whether there is oil spill in the target waters, and further, the oil spill information also includes the extent of oil spill in the target waters. The location information corresponding to the oil spill information refers to, for example, the specific location information of the oil spill and / or the location information of the oil spill detection device 1 in the waters.

[0083] It should be noted that the leakage of hazardous oily chemicals at sea is a serious environmental disaster. Such emergencies not only pose a direct threat to the marine ecosystem, but may also have a profound impact on the safety of public life and property and marine economic activities. Therefore, when an accident occurs, the first task is to quickly control the source of the leakage and effectively prevent the further spread of pollutants.

[0084] Based on this, the water area oil spill detection device 1 provided by the present application can promptly upload an alarm signal containing location information to a preset monitoring terminal when oily substances are detected floating on the water surface in the corresponding area, so that the monitoring terminal and the user of the monitoring terminal can be informed of the specific geographical location where the oily hazardous chemical leakage occurs, and thus take timely treatment actions.

[0085] The present application also provides a method for detecting oil spills in waters, which can be applied to any one of the waters oil spill detection devices 1 provided in the present application, but is not limited to being applied to the waters oil spill detection device 1 provided in the present application.

[0086] It should also be noted that in the water area oil spill detection device 1 provided in the embodiment of the present application, the control module 20 can be used to execute some or all of the steps of the water area oil spill detection method provided in the embodiment of the present application. For details, please refer to the description of the specific implementation method of the water area oil spill detection method.

[0087] See also Figure 4 , Figure 4 A schematic diagram of a step flow chart of a method for detecting oil spills in waters provided in an embodiment of the present application.

[0088] like Figure 4 As shown, the method for detecting oil spill in water areas provided in the embodiment of the present application at least includes steps S1 to S6.

[0089] Step S1, collecting reflected light signals of the target water area, where the reflected light signals are light signals reflected by the target water area based on the incident detection signals.

[0090] Specifically, the reflected light signal is generated by the target water area under the stimulation of the incident detection signal, and the reflected light signal of the target water area can be collected by the light collection module 10 in the water area oil spill detection device 1. Exemplarily, the detection signal includes but is not limited to ultraviolet light, strong purple light or one of other light signals, and the light collection module 10 includes a silicon photomultiplier tube (SiPM).

[0091] exist Figure 3 In the scenario shown, taking the detection signal including strong purple light as an example, there is oily substance floating on the surface of the target water area. Then, in the process of the detection signal irradiating the target water area, the oily substance floating on the surface of the target water area generates fluorescence (i.e., reflected light signal) under the excitation of the strong purple light, and is collected by the light collection module 10.

[0092] In some embodiments, step S1 of collecting reflected light signals from the target water area includes:

[0093] Acquiring ambient temperature information of the photodetector, and determining a target operating voltage of the photodetector according to the ambient temperature information;

[0094] The voltage input to the photodetector is adjusted according to the target operating voltage, so that the photodetector collects the reflected light signal based on the target operating voltage.

[0095] It should be noted that the photodetector is, for example, a silicon photomultiplier tube or other detector that can convert optical signals into electrical signals. The working performance of the photodetector depends on the input voltage provided to it. It works normally to collect reflected light signals under the condition that the input voltage reaches the target operating voltage.

[0096] See also Figure 5 , Figure 5 A schematic diagram of a temperature-voltage control closed loop in a method for detecting oil spills in water areas provided in an embodiment of the present application.

[0097] like Figure 5 As shown, the water area oil spill detection method provided in the embodiment of the present application also designs a temperature-voltage control closed loop, so as to ensure that the photoelectric detector can maintain stable working performance under a wide range of external temperature conditions through the closed loop, thereby stably collecting reflected light signals and improving the versatility and stability of the water area oil spill detection method and the water area oil spill detection device 1.

[0098] Specifically, the temperature-voltage control closed loop is composed of a controller in the control module 20 , an analog-to-digital converter, a temperature sensor, a switching regulator, and a photodetector in the control module 20 , wherein the controller is, for example, a MCU (Microcontroller Unit).

[0099] More specifically, taking the photoelectric sensor as a silicon photomultiplier tube as an example, the controller detects the temperature T of the photoelectric detector through a temperature sensor. siPM , and according to the detected temperature T SiPM Calculate the input voltage V required for the photodetector to work properly at the current temperature out (ie, target operating voltage), the calculation formula is:

[0100] V out =0.0345×T SiPM +27.38.

[0101] Then, by adjusting the duty cycle of the PWM (pulse width modulation) signal output to the switching regulator, the calculation formula is:

[0102]

[0103] After receiving the PWM signal, the switching regulator converts the onboard voltage into a stable target operating voltage according to the duty cycle of the PWM signal and provides it to the photodetector to ensure that the photodetector can stably collect the reflected light signal within a wide external temperature range.

[0104] The onboard voltage is a constant voltage provided by the water area oil spill detection device or other device that executes the method, and the voltage value of the target working voltage matches the duty cycle of the PWM signal.

[0105] Furthermore, under the condition that a stable target operating voltage is input to the photodetector, the photodetector collects the reflected light signal based on the target operating voltage. Subsequently, the weak electrical signals converted from the light signals are processed by the amplification and filtering circuits and transmitted to the analog-to-digital converter. The control module communicates with the analog-to-digital converter to obtain the voltage value of the incident light signal that has been converted into a digital format.

[0106] See also Figure 6 , Figure 6 Another step flow chart of the method for detecting oil spills in waters provided in an embodiment of the present application.

[0107] like Figure 6 As shown, in some embodiments, the method for detecting oil spills in waters provided in the embodiments of the present application further includes step S0 before step S1: outputting a detection signal to the target waters according to the target operation mode.

[0108] Specifically, the target operation mode includes one of a single operation mode and a continuous operation mode; wherein, outputting a detection signal to the target water area according to the target operation mode includes:

[0109] In the single operation mode, the detection signal is output to the target water area in response to the output command;

[0110] In the continuous operation mode, a detection signal is output to the target water area when the preset detection signal output conditions are met. The detection signal output conditions include: when a start instruction corresponding to the continuous operation mode is received, or after the process of determining the oil spill information of the target water area based on the reflected light signal corresponding to the previous detection signal is completed.

[0111] Specifically, the single operation mode means that the light output module 30 outputs only one detection signal after responding to the output instruction, while the continuous operation mode means that the light output module 30 continuously outputs multiple detection signals after responding to the output instruction. Specifically, after the process of determining the oil spill information of the target water area by the reflected light signal corresponding to the previous detection signal is completed, the next detection signal is output, so as to determine the oil spill information of the target water area according to the reflected light signal corresponding to the next detection signal, thereby avoiding mutual interference between different detection signals, and the continuous operation mode can meet the operational requirements of the water area oil spill detection device 1 to continuously monitor the oil spill information.

[0112] Step S2: Generate a digital signal time series matching the spectral information according to the spectral information of the reflected light signal.

[0113] Specifically, the form of the digital signal time series is, for example: D[n]={D1, D2, D3, ..., Dn}, where D1, D2, D3, ..., Dn represent spectral information at different time nodes.

[0114] In some embodiments, step S2 generates a digital signal time series matching the spectral information according to the spectral information of the reflected light signal, including:

[0115] Filtering and amplifying the reflected light signal to obtain an optimized light signal;

[0116] The optimized optical signal is sampled according to a preset sampling period to obtain multiple groups of time-discrete voltage data;

[0117] Multiple sets of voltage data are combined into a digital signal time series based on the time order of time nodes.

[0118] It should be noted that each set of voltage data represents the light intensity of the reflected light signal at different time nodes, and different time nodes are discrete from each other, wherein the higher the voltage data, the higher the light intensity of the reflected light signal.

[0119] Specifically, sampling the optimized light signal according to a preset sampling period helps to clearly distinguish between the stray light of the external environment and the reflected light signal of interest when analyzing the reflected light signal data, ensuring that during the sampling period, most of the fluorescence excited by the surface material of the target water area is at least triggered by the water area oil spill detection device 1 or the light output module 30 that executes the method. It should also be noted that at least one of filtering and amplifying the reflected light signal to obtain the optimized light signal can reduce the difficulty of processing the light signal.

[0120] Step S3: using a preset wavelet function to perform discrete transformation on the digital signal time series to obtain a coefficient matrix, wherein the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies.

[0121] In some implementations, step S3 uses a preset wavelet function to perform a discrete transformation on the digital signal time series, including:

[0122] A convolution operation is performed on the digital signal time series using a preset wavelet function to obtain a plurality of wavelet coefficients, and different wavelet coefficients are used to characterize the signal characteristics of the reflected light signal at different scales and / or different frequencies;

[0123] A coefficient matrix is ​​constructed according to the wavelet coefficients, wherein the elements in the coefficient matrix are the wavelet coefficients.

[0124] It should be noted that using a preset wavelet function to perform discrete transformation (wavelet transform) on a digital signal time series is a mathematical analysis method, specifically decomposing the digital signal time series into a series of wavelet functions, thereby analyzing the signal or function at different scales. The basic steps of wavelet transform are to determine a preset wavelet function, and then perform inner product of the digital signal time series with various translations and expansions of the preset wavelet function to obtain a plurality of different decimal coefficients. These decimal coefficients describe the signal characteristics of the reflected light signal at different scales and / or different frequencies.

[0125] Exemplarily, in some embodiments, the preset wavelet function may use Ricker wavelet (Mexican hat wavelet), and its function expression is as follows:

[0126]

[0127] Furthermore, the above formula can be simplified as follows:

[0128]

[0129] Wherein, t represents the sampling interval, and f represents the center frequency of the preset wavelet function; the water area oil spill detection device 1 or the control module executing the present method generates a Ricker wavelet with the preset center frequency and sampling interval, and then performs a convolution operation on the digital signal time series D[n] to obtain the wavelet coefficients, and finally constructs a coefficient matrix as the output sequence φ(t, f) using the wavelet coefficients as matrix elements, so that the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies.

[0130] Step S4: Perform denoising processing on the coefficient matrix to obtain a denoising matrix, and reconstruct and generate a denoised signal time series according to the denoising matrix.

[0131] In some implementations, step S4 performs denoising on the coefficient matrix to obtain a denoised matrix, including:

[0132] Extracting elements in the coefficient matrix to obtain multiple wavelet coefficients;

[0133] Determine a filtering threshold according to the plurality of wavelet coefficients, and screen out abnormal coefficients from the plurality of wavelet coefficients based on the filtering threshold;

[0134] The abnormal coefficients in the coefficient matrix are set to zero to obtain the denoised matrix.

[0135] Specifically, after generating the coefficient matrix, multiple elements (i.e., wavelet coefficients) in the coefficient matrix are extracted, and then a filtering threshold is calculated based on the multiple wavelet coefficients, and wavelet coefficients that are less than the filtering threshold are screened out from the multiple wavelet coefficients as abnormal coefficients; the position of the abnormal coefficient in the coefficient matrix when it is a matrix element is determined, the abnormal coefficient at the position is found and set to 0, and then a denoising matrix is ​​obtained.

[0136] The filtering threshold is calculated according to a plurality of wavelet coefficients, for example, by calculating an average value of some or all of the wavelet coefficients and using the average value as the filtering threshold.

[0137] In some implementations, step S4 generates a denoised signal time series based on the denoising matrix reconstruction, including:

[0138] The denoising matrix reconstructs the denoised signal time series layer by layer through upsampling, filtering and addition operations.

[0139] Specifically, the coefficients in the denoising matrix can be divided into detail coefficients corresponding to the high-frequency part and approximate coefficients corresponding to the low-frequency part. Based on the previously preset wavelet function, the detail coefficients in the denoising matrix are upsampled (zeros are inserted) using an inverse filter; then the approximate coefficients are also upsampled and passed through an inverse detail filter (for example, an inverse high-pass filter) and passed through an inverse approximate filter (for example, an inverse low-pass filter); finally, the filtered detail coefficients are aligned with the approximate coefficients and added to reconstruct a higher-level approximate coefficient; this process is repeated recursively until an approximate version of the original signal is reconstructed to obtain a denoised signal time series.

[0140] See also Figure 7 , Figure 7 A schematic diagram of a digital signal time series and a noise reduction signal time series in a method for detecting oil spills in waters provided in an embodiment of the present application.

[0141] like Figure 7 As shown, by utilizing the wavelet function to discretely transform the digital signal time series into a coefficient matrix, the coefficient matrix is ​​denoised to obtain a denoised matrix, so that the obtained denoised matrix is ​​smoother, clearer, and has less noise than the digital signal time series before processing. In the subsequent processing flow, it is easier to accurately separate the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area.

[0142] Step S5: Separate the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area from the noise reduction signal time series.

[0143] By using wavelet function to discretely transform the digital signal time series into a coefficient matrix, denoising the coefficient matrix to obtain a denoised matrix, and restoring the denoised matrix to a smooth, clear, and low-noise denoised signal time series, it is easier to accurately separate the background signal and the target signal, thereby improving the accuracy of oil spill identification. Moreover, after a series of processing such as discrete transformation, denoising, and inverse transformation, the processing difficulty is reduced and the speed is increased.

[0144] In some embodiments, the detection signal is a periodically flashing light signal, and step S5 separates the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area from the noise reduction signal time series, including:

[0145] Constructing a corresponding signal strength curve according to the noise reduction signal time series, and identifying a curve trough in the signal strength curve;

[0146] The background signal and the target signal are separated from the noise reduction signal time series according to the curve trough, wherein the intensity amplitude of the curve trough corresponds to the amplitude of the background signal.

[0147] It should be noted that the denoised signal time series is, for example: d[n] = {d1, d2, d3, ..., dn}, where d1, d2, d3, ..., dn represent the reflected light signal intensity of the target water area at different time nodes, and the signal intensity curve can be constructed using the reflected light signal intensity at different time nodes in the denoised signal time series (i.e., d1, d2, d3, ..., dn).

[0148] Based on the fact that the detection signal is a periodically flashing light signal (such as strong purple light), the constructed signal intensity curve is a periodically fluctuating curve with clear curve peaks and curve troughs. When the detection signal is irradiated to the target water area, the reflected light signal is mainly composed of fluorescence reflected by the oil spill floating on the water surface. Therefore, the curve trough represents the background signal corresponding to the target water area, and the curve peak represents the target signal corresponding to the surface material of the target water area.

[0149] After identifying the peaks and troughs in the signal strength curve, the background signal is extracted according to the troughs of the curve, and the target signal is extracted according to the peaks of the curve.

[0150] Step S6: Identify the surface material type of the target water area according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type.

[0151] In some embodiments, step S6 identifies the surface material type of the target water area according to the background signal and the target signal, including:

[0152] Calculate the signal difference at different time nodes according to the background signal and the target signal to generate a signal difference sequence;

[0153] Calculate the abnormal probability corresponding to each time node according to the signal difference sequence, and select the nodes to be evaluated from the time nodes according to the abnormal probability;

[0154] When the node to be evaluated meets the preset abnormal judgment condition, the surface material type is determined to be an oily substance;

[0155] Among them, the preset abnormal judgment conditions include:

[0156] In the adjacent time interval of the node to be evaluated, the fluctuation of the background signal is less than the fluctuation threshold; and the difference judgment ratio between the target signal and the background signal is greater than the ratio threshold.

[0157] Exemplarily, the target signal can be expressed as S[n]={S1, S2, S3,…, Sn}, and the background signal can be expressed as B[n]={B1, B2, B3,…, Bn}, wherein S1, S2, S3,…, Sn are the target signal strengths at each time node, B1, B2, B3,…, Bn are the background signal strengths at each time node, and S1 corresponds to the time point of B1, S2 corresponds to the time point of B2, Sn corresponds to the time point of Bn, and so on.

[0158] Based on this, the signal differences at different time nodes can be expressed as S1-B1, S2-B2, S3-B3,…, Sn-Bn, and the signal difference sequence can be expressed as R[n]=S[n]-B[n]={S1-B1, S2-B2, S3-B3,…, Sn-Bn}.

[0159] After determining the signal difference sequence, the abnormal probability corresponding to each time node is calculated according to the signal difference sequence, wherein the calculation method of the abnormal probability Percent corresponding to each time node is:

[0160]

[0161] Then, whether the time node is a node to be evaluated is determined according to the abnormal probability of each time node, so as to screen out the nodes to be evaluated. For example, the time node whose corresponding abnormal probability is greater than a preset probability threshold can be used as the node to be evaluated.

[0162] After the nodes to be evaluated are screened out, the nodes to be evaluated are evaluated according to the preset abnormal judgment conditions.

[0163] Specifically, when executing this method, when the node to be evaluated simultaneously satisfies the first evaluation condition "in the adjacent time interval of the node to be evaluated, the fluctuation of the background signal is less than the fluctuation threshold" and the second evaluation condition "in the adjacent time interval of the node to be evaluated, the difference judgment ratio between the target signal and the background signal is greater than the ratio threshold", the surface material type of the target water area can be determined as oily substance.

[0164] It should be noted that the first evaluation condition represents that the background signal B[n] does not change much between adjacent cycles, while the second evaluation condition represents that there are more locations where significant growth points appear in the signal difference sequence between the target signal and the background signal.

[0165] For example, in the second evaluation condition, the difference judgment ratio Ratio when a significant growth point appears can be calculated by the following formula:

[0166]

[0167] like Figure 6 As shown, in some embodiments, after determining the oil spill information of the target waters according to the surface material type, the method further includes:

[0168] Step S7: when it is determined according to the oil spill information that oil spill occurs in the target waters or the extent of the oil spill reaches a preset extent, an alarm signal is generated and sent to a preset monitoring terminal; wherein the alarm signal at least includes location information corresponding to the oil spill information.

[0169] It should be understood that the oil spill information at least includes whether there is oil spill in the target waters, and further, the oil spill information also includes the extent of oil spill in the target waters. The location information corresponding to the oil spill information refers to, for example, the specific location information of the oil spill and / or the location information of the oil spill detection device 1 in the waters.

[0170] It should be noted that the leakage of hazardous oily chemicals at sea is a serious environmental disaster. Such emergencies not only pose a direct threat to the marine ecosystem, but may also have a profound impact on the safety of public life and property and marine economic activities. Therefore, when an accident occurs, the first task is to quickly control the source of the leakage and effectively prevent the further spread of pollutants.

[0171] Based on this, the water area oil spill detection device 1 provided by the present application can promptly upload an alarm signal containing location information to a preset monitoring terminal when oily substances are detected floating on the water surface in the corresponding area, so that the monitoring terminal and the user of the monitoring terminal can be informed of the specific geographical location where the oily hazardous chemical leakage occurs, and thus take timely treatment actions.

[0172] In summary, the embodiments of the present application provide a method for detecting oil spill in water areas and a device for detecting oil spill in water areas 1, wherein the method for detecting oil spill in water areas comprises: collecting a reflected light signal of a target water area, wherein the reflected light signal is a light signal reflected by the target water area based on an incident detection signal; generating a digital signal time series matching the spectral information according to the spectral information of the reflected light signal; performing a discrete transformation on the digital signal time series using a preset wavelet function to obtain a coefficient matrix, and the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies; performing denoising processing on the coefficient matrix to obtain a denoising matrix, and reconstructing a denoised signal time series according to the denoising matrix; separating a background signal corresponding to the target water area and a target signal corresponding to the surface material of the target water area from the denoised signal time series; identifying the surface material type of the target water area according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type. The present application utilizes wavelet function to discretely transform digital signal time series into coefficient matrix, performs denoising on the coefficient matrix to obtain denoised matrix, and restores the denoised matrix to a smooth, clear and low-noise denoised signal time series, so as to utilize the denoised signal time series to identify the surface material type of the target waters, thereby improving the accuracy of identifying oil spills.

[0173] It should be understood that the module structure diagram shown in the accompanying drawings is only an example and does not necessarily include all the connection relationships between structures. In the description of this application, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, and it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0174] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0175] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0176] It should also be understood that the term "and / or" used in the specification of this application and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations. It should be noted that, in this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "including a..." does not exclude the presence of other identical elements in the process, method, article or system including the element.

[0177] The serial numbers of the embodiments of the present application are for description only and do not represent the advantages and disadvantages of the embodiments. The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for detecting oil spill in waters, characterized in that: include: Collecting a reflected light signal of a target water area, wherein the reflected light signal is a light signal reflected by the target water area based on an incident detection signal; Generating a digital signal time series matching the spectral information according to the spectral information of the reflected light signal; Using a preset wavelet function to perform discrete transformation on the digital signal time series to obtain a coefficient matrix, wherein the elements in the coefficient matrix correspond to the signal characteristics of the reflected light signal at multiple scales and / or frequencies; Performing denoising processing on the coefficient matrix to obtain a denoising matrix, and reconstructing and generating a denoised signal time series according to the denoising matrix; Separating a background signal corresponding to the target water area and a target signal corresponding to the surface material of the target water area from the noise reduction signal time series; The surface material type of the target water area is identified according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type.

2. The method according to claim 1, characterized in that The method further includes outputting the detection signal to the target water area according to a target operation mode, wherein the target operation mode includes one of a single operation mode and a continuous operation mode; Wherein, outputting the detection signal to the target water area according to the target operation mode includes: In the single operation mode, outputting a detection signal to the target water area in response to an output instruction; In the continuous operation mode, a detection signal is output to the target water area when a preset detection signal output condition is met, and the detection signal output condition includes: when a start instruction corresponding to the continuous operation mode is received, or after the process of determining the oil spill information of the target water area according to the reflected light signal corresponding to the previous detection signal is completed.

3. The method according to claim 1, characterized in that The collecting of reflected light signals from the target water area comprises: Acquiring ambient temperature information of the photodetector, and determining a target operating voltage of the photodetector according to the ambient temperature information; The voltage input to the photodetector is adjusted according to the target operating voltage, so that the photodetector collects the reflected light signal based on the target operating voltage.

4. The method according to claim 1, characterized in that The step of generating a digital signal time series matching the spectral information according to the spectral information of the reflected light signal comprises: Performing filtering and amplification processing on the reflected light signal to obtain an optimized light signal; Sampling the optimized optical signal according to a preset sampling period to obtain multiple groups of time-discrete voltage data; The plurality of sets of the voltage data are combined into the digital signal time series based on the time sequence of the time nodes.

5. The method according to claim 1, characterized in that The discrete transformation of the digital signal time series by using a preset wavelet function comprises: Using the preset wavelet function to perform a convolution operation on the digital signal time series to obtain a plurality of wavelet coefficients, and different wavelet coefficients are used to characterize the signal characteristics of the reflected light signal at different scales and / or different frequencies; The coefficient matrix is ​​constructed according to the wavelet coefficients, wherein the elements in the coefficient matrix are the wavelet coefficients.

6. The method according to claim 5, characterized in that The step of performing denoising processing on the coefficient matrix to obtain a denoised matrix includes: Extracting elements in the coefficient matrix to obtain a plurality of wavelet coefficients; Determine a filtering threshold according to the plurality of wavelet coefficients, and screen out abnormal coefficients from the plurality of wavelet coefficients based on the filtering threshold; The abnormal coefficients in the coefficient matrix are set to zero to obtain the noise reduction matrix.

7. The method according to claim 6, characterized in that The step of reconstructing and generating a noise reduction signal time series according to the noise reduction matrix comprises: The denoising matrix reconstructs the denoised signal time series layer by layer through upsampling, filtering and adding operations.

8. The method according to any one of claims 1 to 7, characterized in that: The detection signal is a periodically flashing light signal, and the background signal corresponding to the target water area and the target signal corresponding to the surface material of the target water area are separated from the noise reduction signal time series, including: Constructing a corresponding signal strength curve according to the noise reduction signal time series, and identifying troughs and peaks in the signal strength curve; The background signal and the target signal are separated from the noise reduction signal time series according to the troughs and peaks, wherein the intensity amplitude of the curve troughs corresponds to the amplitude of the background signal, and the intensity amplitude of the curve peaks corresponds to the amplitude of the target signal.

9. The method according to any one of claims 1 to 7, characterized in that: The identifying the surface material type of the target water area according to the background signal and the target signal includes: Calculate signal differences at different time nodes according to the background signal and the target signal to generate a signal difference sequence; Calculating the abnormal probability corresponding to each of the time nodes according to the signal difference sequence, and selecting the nodes to be evaluated from the time nodes according to the abnormal probability; When the node to be evaluated meets a preset abnormality judgment condition, determining that the surface material type is an oily material; The preset abnormality judgment conditions include: In adjacent time intervals of the node to be evaluated, the fluctuation of the background signal is less than a fluctuation threshold; and, a difference judgment ratio between the target signal and the background signal is greater than a ratio threshold.

10. The method according to any one of claims 1 to 7, characterized in that: After determining the oil spill information of the target waters according to the surface material type, the method further includes: When it is determined according to the oil spill information that oil spill occurs in the target waters or the extent of oil spill reaches a preset extent, an alarm signal is generated and the alarm signal is sent to a preset monitoring terminal; Wherein, the alarm signal at least includes location information corresponding to the oil spill information.

11. A water area oil spill detection device, characterized in that: include: A light collection module, used for collecting a reflected light signal of a target water area, wherein the reflected light signal is a light signal reflected by the target water area based on an incident detection signal, and the reflected light signal includes a plurality of sub-light signals with different frequency information; A control module is connected to the light collection module, and is used to generate a digital signal time series that matches the spectral information according to the spectral information of the reflected light signal; discretely transform the digital signal time series using a preset wavelet function to obtain a coefficient matrix, and the elements in the coefficient matrix correspond to the sub-light signals one by one; perform denoising on the coefficient matrix to obtain a denoising matrix, and reconstruct the denoising matrix to generate a denoised signal time series; separate a background signal corresponding to the target water area and a target signal corresponding to the surface material of the target water area from the denoised signal time series; identify the surface material type of the target water area according to the background signal and the target signal, so as to determine the oil spill information of the target water area according to the surface material type.

12. The water area oil spill detection device according to claim 11, characterized in that: The device further comprises an optical output module electrically connected to the control module, and configured to output the detection signal to the target water area according to a target operation mode, wherein the target operation mode comprises one of a single operation mode and a continuous operation mode; Wherein, in the single operation mode, the optical output module outputs a detection signal to the target water area in response to an output instruction; In the continuous operation mode, the light output module outputs a detection signal to the target water area when a preset detection signal output condition is met, and the detection signal output condition includes: when a start instruction corresponding to the continuous operation mode is received, or after the process of determining the oil spill information of the target water area according to the reflected light signal corresponding to the previous detection signal is completed.

13. The water area oil spill detection device according to claim 11, characterized in that: The device also includes an alarm module, which is used to generate an alarm signal and send the alarm signal to a preset monitoring terminal when it is determined according to the oil spill information that oil spill occurs in the target water area or the extent of oil spill reaches a preset extent; Wherein, the alarm signal at least includes location information corresponding to the oil spill information.

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