A real-time monitoring method and system for estuary saltwater tide based on electrical resistance tomography

Abstract

The present invention relates to the field of hydrological and water resource measurement technology, and discloses a real-time monitoring method and system for estuarine saltwater tides based on electrical resistance tomography. The method outputs current to an electrode array in the area to be monitored to excite the electric field of the electrode array, collects the supply current and observed voltage difference in the electrode array according to a preset running electrode method, calculates the apparent resistivity of the electrode array based on the collected data, and uses a linear back-projection algorithm to reconstruct and display the image, thereby obtaining a resistivity distribution map of the two-dimensional cross-section of the estuary and obtaining intuitive real-time monitoring results. The present invention applies electrical resistance tomography technology to the real-time monitoring of the two-dimensional cross-sectional characteristics of the estuary saltwater tide, taking into account the equipment's seawater corrosion protection and river ecological safety. This method has a solid physical principle, is easy to operate, and has high measurement accuracy, and can accurately monitor the two-dimensional cross-sectional characteristics of the estuary saltwater tide in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrology and water resources measurement, and in particular to a real-time monitoring method and system for estuary saltwater tide based on electrical resistance tomography. Background Art

[0002] Saltwater tides are a major factor affecting the water security of estuarine cities, directly affecting the water supply for local residents, farmland irrigation, and corporate production. Especially in the context of global climate change, with rising sea levels and frequent extreme droughts, coupled with the impact of human activities at the Pearl River Estuary and river channel incision, the estuaries of my country's major rivers flowing into the sea are increasingly affected by the upstream movement of saltwater tides. Accurately depicting the spatiotemporal variations of saltwater tides is the primary basis for comprehensive prevention and control of saltwater tides, requiring the establishment of a high-precision and timely monitoring and early warning system. Due to the complexity of water and salt movement in tidal river networks, a detailed description of the distribution characteristics of saltwater in the longitudinal (river channel direction) and vertical (cross-section direction) directions is of great significance in the precise early warning and forecast of saltwater tides.

[0003] However, current saltwater monitoring, both domestically and internationally, still relies primarily on automated river water quality monitoring stations. However, it should be noted that the causes of saltwater upstream are complex, and the saltwater process exhibits significant spatial inconsistency. Point-scale data acquired by traditional water quality monitoring stations cannot fully capture the saltwater characteristics of the river's two-dimensional space. While saltwater characteristics can be captured in spatiotemporal scales using multi-point sensors combined with spatial interpolation, installing and maintaining a large number of sensors consumes manpower and material resources and impacts mainstream navigation. Therefore, developing a real-time saltwater monitoring technology with large-scale monitoring capabilities and the ability to precisely characterize saltwater cross-sectional characteristics is crucial for improving the accuracy of monitoring, early warning, and forecasting, and enhancing saltwater management capabilities. Summary of the Invention

[0004] The present invention provides a real-time monitoring method and system for estuarine salt tide based on electrical resistance tomography, which has solid physical principles, simple operation, high measurement accuracy, and can accurately monitor the two-dimensional cross-sectional characteristics of estuarine salt tide in real time.

[0005] In order to solve the above technical problems, the first embodiment of the present invention provides a real-time monitoring method for estuary saltwater tide based on electrical resistance tomography, comprising:

[0006] Outputting an excitation current to the electrode array of the area to be monitored to stimulate the electric field of the electrode array;

[0007] After the electric field of the electrode array is stabilized, the supply current of the electrode array and the voltage difference are collected;

[0008] Calculating the apparent resistivity of the electrode array based on the supplied current and the observed voltage difference of the electrode array;

[0009] According to the apparent resistivity of the electrode array, a linear back-projection algorithm is used to perform image reconstruction to obtain a resistivity distribution map, so as to monitor the two-dimensional cross-sectional characteristics of the estuary saltwater tide in real time.

[0010] The present invention outputs current to the electrode array in the area to be monitored to stimulate the electric field of the electrode array, collects the supply current and observed voltage difference in the electrode array, and calculates the apparent resistivity of the electrode array based on the collected data. The linear back projection algorithm is used to reconstruct and display the image to obtain a resistivity distribution map, so as to monitor the two-dimensional cross-sectional characteristics of the estuary salt tide in real time and obtain high-precision measurement results.

[0011] Furthermore, the supply current and the observed voltage difference of the acquisition electrode array are specifically:

[0012] A fixed electrode device is used to fix a plurality of electrodes in the area to be monitored to form an electrode array;

[0013] A first power supply electrode, a second power supply electrode, a first receiving electrode, and a second receiving electrode are arranged on the same straight line perpendicular to the direction of water flow in the area to be monitored, and the distance between the first power supply electrode and the second power supply electrode is controlled to be one electrode distance, the distance between the first receiving electrode and the second receiving electrode is controlled to be one electrode distance, and the distance between the second power supply electrode and the first receiving electrode is controlled to be a plurality of electrode distances; wherein the value of one electrode distance is set in advance;

[0014] changing the electrode positions corresponding to the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode according to a preset running electrode method, and collecting the supply current between the first power supply electrode and the second power supply electrode and the observed voltage difference between the first receiving electrode and the second receiving electrode after each electrode position change;

[0015] The collected supply currents between all first supply electrodes and second supply electrodes are determined to be the supply currents of the electrode array, and the collected observation voltage differences between all first receiving electrodes and second receiving electrodes are determined to be the observation voltage differences of the electrode array.

[0016] The present invention places electrodes in the area to be monitored, with electrodes at each fixed placement point without changing position. A first power supply electrode, a second power supply electrode, a first receiving electrode, and a second receiving electrode are arranged on the same straight line perpendicular to the direction of water flow. The power supply current and the observed voltage difference data at different positions are collected according to a preset running electrode method, which can more conveniently collect more data, thereby improving the accuracy of the measurement results.

[0017] The apparent resistivity of the electrode array is calculated based on the supply current and the observed voltage difference of the electrode array, specifically:

[0018] Calculating a device coefficient of the electrode array according to the distances between the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode;

[0019] The device coefficient of the electrode array is specifically:

[0020]

[0021] Wherein, AM is the distance between the first power supply electrode and the first receiving electrode; AN is the distance between the first power supply electrode and the second receiving electrode; BM is the distance between the second power supply electrode and the first receiving electrode; BN is the distance between the second power supply electrode and the second receiving electrode; K is the device coefficient of the electrode array;

[0022] Calculating the apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode according to the device coefficient of the electrode array, the supply current of the electrode array and the observed voltage difference of the electrode array;

[0023] The apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode is specifically:

[0024]

[0025] Wherein, ρ is the apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode; K is the device coefficient of the electrode array; ΔV is the observed voltage difference of the electrode array; I is the supply current of the electrode array;

[0026] The apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode is determined as the apparent resistivity of the electrode array.

[0027] After collecting the supply current and observation voltage difference of the electrode array, the present invention converts the collected data into the apparent resistivity of the midpoint between the second supply electrode and the first receiving electrode due to the high ion concentration and good conductivity of seawater. This can accurately distinguish the salt water at the estuary and obtain more accurate measurement results.

[0028] Furthermore, according to the apparent resistivity of the electrode array, a linear back-projection algorithm is used to perform image reconstruction, specifically:

[0029] Transmitting the apparent resistivity to a computer by means of DSP technology and radio technology;

[0030] filtering the apparent resistivity using a back-projection weighted matrix to obtain data to be reconstructed;

[0031] Image reconstruction is performed using a linear back-projection algorithm based on the data to be reconstructed.

[0032] Before image reconstruction, the present invention will first filter the collected apparent resistivity to improve the accuracy of image reconstruction. Since the linear back projection algorithm is simple, has a small amount of calculation, and a fast image reconstruction speed, the use of the linear back projection algorithm for image reconstruction can obtain measurement results more quickly, thereby improving the monitoring work efficiency.

[0033] Furthermore, the electric field of the electrode array is stable, specifically:

[0034] After outputting the excitation current to the electrode array, the voltage difference between any two electrodes in the electrode array is detected in real time;

[0035] If the voltage difference between any two electrodes is within a preset voltage range within a preset time period, it is determined that the electric field of the current electrode array is stable.

[0036] The electrode array of the present invention has several electrodes. After the electrode array receives the excitation current, the voltage difference between any two electrodes can be monitored. If the voltage difference between the electrodes is monitored to be stable, it is determined that the electric field of the electrode array is stable at this time, thereby ensuring the accuracy and security of the collected data.

[0037] Furthermore, the excitation current is specifically:

[0038] Convert the input current into a DC current with adjustable voltage;

[0039] The DC current of the adjustable voltage is determined to be the excitation current.

[0040] After the power supply provides input current, the present invention converts the input current into a DC current with adjustable voltage according to the requirements of data collection. The current can be flexibly adjusted according to different requirements, making it applicable to various situations and ensuring the safety of the data collection process.

[0041] Furthermore, the fixed electrode device is specifically:

[0042] The fixed electrode device is used to fix the electrodes in the electrode array and control the direction of the electrodes in the electrode array to be the same as the direction of water flow in the area to be monitored.

[0043] The fixed electrode device of the present invention can fix the electrodes in the electrode array to ensure that the direction of the electrodes is the same as the direction of water flow in the monitored area, thereby collecting more accurate voltage difference data and ensuring the accuracy of real-time monitoring results.

[0044] Furthermore, the direction of controlling the electrodes in the electrode array to be the same as the direction of water flow in the area to be monitored is specifically:

[0045] The fixed electrode device includes an electrode connector, a cable and a fixing nail;

[0046] The electrode connector is used to connect the electrode and the cable;

[0047] The fixing nail is composed of a nail head, a nail body and a nail tail;

[0048] Wherein, a streamlined groove is provided in the middle of the nail head, and the streamlined groove is used to place the electrode;

[0049] The same streamlined protrusion structure is provided on both sides of the nail head, and a buckle structure and a buckle component are provided on the top middle part of the streamlined protrusion structure, and the buckle structure and the buckle component are used to fix the interconnected electrodes and cables on the fixing nail;

[0050] By controlling the streamline direction of the streamlined protruding structure of the nail head to be consistent with the direction of water flow, the direction of the electrodes in the electrode array is controlled to be consistent with the direction of water flow in the area to be monitored.

[0051] The fixed electrode device of the present invention includes an electrode connector, a cable and a fixing nail. The nail head of the fixing nail is provided with corresponding structures on both sides and in the middle to fix the electrodes required for data collection and improve the accuracy of the data.

[0052] The present invention provides a real-time monitoring method for estuarine saltwater tides using electrical resistance tomography. The method outputs current to an electrode array in a monitored area to excite the electric field of the electrode array, collects the supply current and observed voltage difference in the electrode array according to a preset running electrode method, calculates the apparent resistivity of the electrode array based on the collected data, and uses a linear back-projection algorithm to perform image reconstruction and display, thereby obtaining a resistivity distribution map, thereby monitoring the two-dimensional cross-sectional characteristics of the estuarine saltwater tide in real time and obtaining high-precision measurement results.

[0053] Accordingly, the present invention provides a real-time monitoring system for saltwater tides in estuaries using electrical resistance tomography, comprising: an excitation module, an acquisition module, a calculation module, and a reconstruction module;

[0054] The excitation module is used to output an excitation current to the electrode array of the area to be monitored to excite the electric field of the electrode array;

[0055] The acquisition module is used to collect the supply current and observe the voltage difference of the electrode array after the electric field of the electrode array is stabilized;

[0056] The calculation module is used to calculate the apparent resistivity of the electrode array based on the supply current and the observed voltage difference of the electrode array;

[0057] The reconstruction module is used to perform image reconstruction using a linear back-projection algorithm based on the apparent resistivity of the electrode array to obtain a resistivity distribution map, so as to monitor the two-dimensional cross-sectional characteristics of the estuary saltwater tide in real time.

[0058] Furthermore, the reconstruction module includes: a transmission unit, an acquisition unit and a reconstruction unit;

[0059] The transmission unit is used to transmit the apparent resistivity to a computer by means of DSP technology and radio technology;

[0060] The acquisition unit is used to filter the apparent resistivity using a back-projection weighted matrix to obtain data to be reconstructed;

[0061] The reconstruction unit is used to perform image reconstruction using a linear back-projection algorithm based on the data to be reconstructed.

[0062] The present invention provides a real-time monitoring system for estuarine salt tides based on electrical resistance tomography. The device is based on the organic combination of modules, which can improve the convenience of monitoring, increase the accuracy of measurement results, and realize real-time and accurate monitoring of the two-dimensional cross-sectional characteristics of estuarine salt tides. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A schematic flow chart of an embodiment of a method for real-time monitoring of estuary saltwater tides based on electrical resistance tomography provided by the present invention;

[0064] Figure 2 A schematic diagram of the voltage difference acquisition method provided by the present invention;

[0065] Figure 3 A schematic diagram of a fixed electrode device provided by the present invention;

[0066] Figure 4 Another schematic diagram of the fixed electrode device provided by the present invention;

[0067] Figure 5 Another schematic diagram of the fixed electrode device provided by the present invention;

[0068] Figure 6 Another schematic diagram of the fixed electrode device provided by the present invention;

[0069] Figure 7 A schematic structural diagram of an embodiment of a real-time monitoring system for estuary saltwater tides based on electrical resistance tomography provided by the present invention;

[0070] Figure 8 A schematic diagram of a real-time monitoring device for estuary saltwater tide based on electrical resistance tomography provided by the present invention;

[0071] Figure 9 A schematic diagram of the principle of the real-time monitoring method for estuary saltwater tide based on electrical resistance tomography provided by the present invention. DETAILED DESCRIPTION

[0072] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0073] Example 1

[0074] like Figure 1 FIG. 1 is a flow chart of an embodiment of a method for real-time monitoring of estuary saltwater tides based on electrical resistance tomography provided by the first embodiment of the present invention. The method includes steps 101 to 104, and each step is specifically as follows:

[0075] Step 101: outputting an excitation current to the electrode array of the area to be monitored to stimulate the electric field of the electrode array.

[0076] In the first embodiment of the present invention, the excitation current is specifically:

[0077] Convert the input current into a DC current with adjustable voltage;

[0078] The DC current of the adjustable voltage is determined to be the excitation current.

[0079] As an example of the first embodiment of the present invention, after a power supply provides input voltage and input current to the electrode array in the monitored area, these input voltage and input current need to be adjusted for operational safety. A DC / DC converter is used to convert the input voltage, selecting an output voltage within the safe voltage range for estuary operations. Through the control of a selection controller, the stabilization of a constant current source, and the current direction change of a commutator, the input current is converted into a direct current with an adjustable voltage, serving as the excitation current for the electrode array, according to data collection requirements. By flexibly adjusting the output voltage and output current, the system can be adapted to various situations, ensuring the safety of the data collection process.

[0080] Step 102: After the electric field of the electrode array is stabilized, the supply current of the electrode array is collected and the voltage difference is observed.

[0081] In the first embodiment of the present invention, the electric field of the electrode array is stable, specifically:

[0082] After outputting the excitation current to the electrode array, the voltage difference between any two electrodes in the electrode array is detected in real time;

[0083] If the voltage difference between any two electrodes is within a preset voltage range within a preset time period, it is determined that the electric field of the current electrode array is stable.

[0084] In the first embodiment of the present invention, the supply current of the electrode array and the observed voltage difference are collected as follows:

[0085] A fixed electrode device is used to fix a plurality of electrodes in the area to be monitored to form an electrode array;

[0086] A first power supply electrode, a second power supply electrode, a first receiving electrode, and a second receiving electrode are arranged on electrodes on the same straight line perpendicular to the direction of water flow in the area to be monitored, and the distance between the first power supply electrode and the second power supply electrode is controlled to be one electrode distance, the distance between the first receiving electrode and the second receiving electrode is controlled to be one electrode distance, and the distance between the second power supply electrode and the first receiving electrode is controlled to be a plurality of electrode distances; wherein the value of one electrode distance is set in advance;

[0087] changing the electrode positions corresponding to the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode according to a preset running electrode method, and collecting the supply current between the first power supply electrode and the second power supply electrode and the observed voltage difference between the first receiving electrode and the second receiving electrode after each electrode position change;

[0088] The collected supply currents between all first supply electrodes and second supply electrodes are determined to be the supply currents of the electrode array, and the collected observation voltage differences between all first receiving electrodes and second receiving electrodes are determined to be the observation voltage differences of the electrode array.

[0089] As an example of the first embodiment of the present invention, the principle of the present invention is basically consistent with the conventional resistivity method. Conductive electrodes can be set at the bottom of the estuary and ensure good contact with the river water. After applying direct current using a suitable power supply to form a stable electric field, the apparent resistivity is obtained by collecting the supply current between the power supply electrodes and the observed voltage difference between the receiving electrodes. Since seawater has a high ion concentration, good conductivity, and lower resistivity than fresh water in the estuary, the salt water at the estuary can be accurately distinguished by using resistance tomography technology based on the different resistivity of the electric field medium. After receiving the excitation current, the electrode array in the area to be detected can detect the voltage difference between any two electrodes. If the value of the voltage difference change is within a preset range within a preset period of time, it can be determined that the electric field of the electrode array is stable at this time. Figure 2As shown, a dipole-dipole device is used for running electrodes. A first power electrode, a second power electrode, a first receiving electrode, and a second receiving electrode are placed on the same straight line perpendicular to the water flow in the monitored area. These electrodes are designated A, B, M, and N, respectively. The distance A to B is one electrode pitch, set to no more than 10 meters. The distance A to B is equal to the distance MN, and the distance BM is an integer multiple of the distance A to B or MN. When the dipole-dipole device begins collecting the supply current between A and B and the observed voltage difference between M and N, the positions of the first power electrode A and the second power electrode B remain unchanged, while the first receiving electrode M and the second receiving electrode N are moved away from the power electrodes A and B. Each time the electrode pitch is moved, data points with different isolation coefficients, n, are collected. After one round of data collection, i.e., when electrodes M and N have reached the preset maximum distance and data corresponding to different isolation coefficients have been collected, the power electrodes A and B are moved right by one electrode pitch, and electrodes M and N are repositioned adjacent to electrodes A and B. A new round of data collection begins, and the above process is repeated until all data points have been collected.

[0090] Step 103: Calculate the apparent resistivity of the electrode array according to the supplied current and the observed voltage difference of the electrode array.

[0091] In the first embodiment of the present invention, the apparent resistivity of the electrode array is calculated based on the supply current and the observed voltage difference of the electrode array, specifically:

[0092] Calculating a device coefficient of the electrode array according to the distances between the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode;

[0093] The device coefficient of the electrode array is specifically:

[0094]

[0095] Wherein, AM is the distance between the first power supply electrode and the first receiving electrode; AN is the distance between the first power supply electrode and the second receiving electrode; BM is the distance between the second power supply electrode and the first receiving electrode; BN is the distance between the second power supply electrode and the second receiving electrode; K is the device coefficient of the electrode array;

[0096] Calculating the apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode according to the device coefficient of the electrode array, the supply current of the electrode array and the observed voltage difference of the electrode array;

[0097] The apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode is specifically:

[0098]

[0099] Wherein, ρ is the apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode; K is the device coefficient of the electrode array; ΔV is the observed voltage difference of the electrode array; I is the supply current of the electrode array;

[0100] The apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode is determined as the apparent resistivity of the electrode array.

[0101] In the first embodiment of the present invention, after collecting the supply current and observed voltage difference of the electrode array, since seawater has a high ion concentration and good conductivity, the collected data is converted into the apparent resistivity of the midpoint between the second supply electrode and the first receiving electrode. This can more accurately distinguish the salt water at the estuary and obtain more accurate measurement results.

[0102] Step 104: performing image reconstruction using a linear back-projection algorithm based on the apparent resistivity of the electrode array to obtain a resistivity distribution map for real-time monitoring of the two-dimensional cross-sectional characteristics of the estuary saltwater tide.

[0103] In the first embodiment of the present invention, image reconstruction is performed using a linear back-projection algorithm based on the apparent resistivity of the electrode array, specifically:

[0104] Transmitting the apparent resistivity to a computer by means of DSP technology and radio technology;

[0105] filtering the apparent resistivity using a back-projection weighted matrix to obtain data to be reconstructed;

[0106] Image reconstruction is performed using a linear back-projection algorithm based on the data to be reconstructed.

[0107] As an example of the first embodiment of the present invention, the apparent resistivity can be transmitted to a computer using DSP technology and radio technology. Since the linear back-projection algorithm has the advantages of simple algorithm, small computational complexity, and fast image reconstruction speed, it is very suitable for qualitative analysis of fast dynamic processes. However, real-time monitoring of saltwater tides requires relatively high image reconstruction speed, so the linear back-projection algorithm is considered for image reconstruction. At the same time, in order to improve the accuracy of the reconstructed image of the linear back-projection algorithm, a back-projection weighting matrix can be first introduced to filter the voltage at the boundary of the sensitive field, and then the back-projection algorithm is used to reconstruct the image. The specific process of using the linear back-projection algorithm for image reconstruction and display is as follows: the measurement field is divided into a finite number of units according to a certain division principle, and after generating the projection field equipotential line coverage matrix and determining the equipotential line area corresponding to each unit, the voltage measurement data is input. After filtering the voltage value, the back-projection algorithm is used to achieve back-projection imaging and display it in the form of an image.

[0108] In the first embodiment of the present invention, the fixed electrode device is specifically:

[0109] The fixed electrode device is used to fix the electrodes in the electrode array and control the direction of the electrodes in the electrode array to be the same as the direction of water flow in the area to be monitored.

[0110] In the first embodiment of the present invention, the direction of the electrodes in the electrode array is controlled to be the same as the direction of the water flow in the monitored area, specifically:

[0111] The fixed electrode device includes an electrode connector, a cable and a fixing nail;

[0112] The electrode connector is used to connect the electrode and the cable;

[0113] The fixing nail is composed of a nail head, a nail body and a nail tail;

[0114] Wherein, a streamlined groove is provided in the middle of the nail head, and the streamlined groove is used to place the electrode;

[0115] The same streamlined protrusion structure is provided on both sides of the nail head, and a buckle structure and a buckle component are provided on the top middle part of the streamlined protrusion structure, and the buckle structure and the buckle component are used to fix the interconnected electrodes and cables on the fixing nail;

[0116] By controlling the streamline direction of the streamlined protruding structure of the nail head to be consistent with the direction of water flow, the direction of the electrodes in the electrode array is controlled to be consistent with the direction of water flow in the area to be monitored.

[0117] As an example of the first embodiment of the present invention, electrodes are set in the area to be monitored, and a fixing device needs to be designed to fix the electrodes in order to accurately collect data. Figure 3 - Figure 6 , a fixing nail and a centralized cable can be used as a fixing device, wherein, (1) is a titanium alloy conductive electrode; (2) is an electrode connector; (3) is a centralized cable; (4) is a streamlined protrusion structure; (5) is a streamlined groove; (6) is a nail body; (7) is a nail tail; (8) is a snap-fit ​​structure; (9) is a snap-fit ​​component. Among them, Figure 3 The left side shows the assembly diagram of the conductive electrode, electrode connector, cable, and fixing nail. Figure 3 On the right Figure 3 The cross-section of the left assembly along the center line, Figure 4 A top view of the combined device. Figure 5 for Figure 4 Schematic diagram of the disassembly, with the top view of the conductive electrode, electrode connector and cable, and the bottom view of the fixing nail; Figure 6The diagram shows a clip with a streamlined raised structure. The left side shows a left view of the fixing nail, and the right side shows an enlarged diagram of the clip structure and the clip component. The width of the clip component is consistent with the width of the streamlined raised structure. The fixing nail includes a nail tail, a nail body, and a nail head. The nail head is provided with a streamlined raised structure, a streamlined groove, a clip structure, and a clip component. The conductive electrode is made of titanium alloy and designed with a streamlined appearance. It is directly connected to the cable through a connector. The outer layer of the cable and the connector are wrapped with polyurethane material. The fixing nail is made of engineering plastic. The bottom part is a diamond-shaped spike, the middle part is a columnar shape, and the upper part is the nail head. The nail head is provided with the same streamlined raised structure on both sides. The top middle part of the structure is provided with a circular groove with a clip structure. The middle of the nail head is a streamlined groove that can be used to place the electrode. When using a fixing device to fix the conductive electrode in the area to be monitored, it is necessary to control the streamline direction of the streamlined protrusion structure of the nail head to be consistent with the direction of water flow, so that the placement direction of the conductive electrode is the same as the direction of water flow in the area to be monitored, thereby collecting more accurate data and ensuring the accuracy of real-time monitoring results.

[0118] Correspondingly, such as Figure 7 2 is a schematic structural diagram of an embodiment of a real-time monitoring system for estuary saltwater tides based on electrical resistance tomography provided by the present invention, the system comprising an excitation module 201, an acquisition module 202, a calculation module 203 and a reconstruction module 204;

[0119] The excitation module 201 is used to output an excitation current to the electrode array of the area to be monitored to excite the electric field of the electrode array;

[0120] The acquisition module 202 is used to acquire the supply current and observe the voltage difference of the electrode array after the electric field of the electrode array is stabilized;

[0121] The calculation module 203 is used to calculate the apparent resistivity of the electrode array based on the supply current and the observed voltage difference of the electrode array;

[0122] The reconstruction module 204 is used to perform image reconstruction using a linear back-projection algorithm based on the apparent resistivity of the electrode array to obtain a resistivity distribution map for real-time monitoring of the two-dimensional cross-sectional characteristics of the estuary saltwater tide.

[0123] In the first embodiment of the present invention, the reconstruction module 204 includes: a transmission unit, an acquisition unit and a reconstruction unit;

[0124] The transmission unit is used to transmit the apparent resistivity to a computer by means of DSP technology and radio technology;

[0125] The acquisition unit is used to filter the apparent resistivity using a back-projection weighted matrix to obtain data to be reconstructed;

[0126] The reconstruction unit is used to reconstruct an image using a linear back-projection algorithm according to the data to be reconstructed.

[0127] In summary, the real-time monitoring method and system for estuarine saltwater tides based on electrical resistance tomography provided by the embodiments of the present invention outputs current to the electrode array in the monitored area to stimulate the electric field of the electrode array, collects the supply current and observed voltage difference in the electrode array according to a preset running pole method, calculates the apparent resistivity of the electrode array based on the collected data, and uses the linear back projection algorithm to reconstruct and display the image, which can obtain a resistivity distribution map of the two-dimensional cross-section of the estuary and obtain intuitive real-time monitoring results. Under the premise of considering the equipment's anti-seawater corrosion and river ecological safety, the present invention applies electrical resistance tomography technology to the real-time monitoring of the two-dimensional cross-sectional characteristics of the estuary saltwater tide. This method has a solid physical principle, is simple to operate, and has high measurement accuracy. It can accurately monitor the two-dimensional cross-sectional characteristics of the estuary saltwater tide in real time.

[0128] Example 2

[0129] like Figure 8 As shown, the second embodiment of the present invention provides a real-time monitoring device for saltwater tide in an estuary based on electrical resistance tomography. The device comprises four parts: a power supply, a host, an electrode array, and an image reconstruction display. The specific structure is as follows:

[0130] 1. The power supply primarily consists of solar panels, batteries, and a charge controller. Solar panels utilize the photoelectric effect to achieve photoelectric conversion. Their primary components include tempered glass, EVA, cells, a backsheet, aluminum alloy, a junction box, and silicone rubber. Cells are the core component of photoelectric conversion and utilize monocrystalline silicon solar cells. Batteries store the electricity generated by solar panels. Their primary technical parameters are voltage and capacity, and batteries of varying voltages and capacities can be selected based on actual needs. The charge controller provides battery charge and discharge protection, preventing overcharge and overdischarge.

[0131] 2. The host consists of four parts: adjustable voltage DC power supply module, electrode conversion module, data acquisition module, and data transmission module. The characteristics of each part are as follows:

[0132] The adjustable voltage DC power supply module is characterized by: its main components include a DC / DC converter, a selection controller, a constant current source and a commutator. The DC / DC converter can convert the input voltage and select the output voltage within a certain range. After the control action of the selection controller, the stabilization action of the constant current source and the change of the current direction by the commutator, the input current is converted into a DC current with an adjustable voltage, which serves as the excitation current of the electrode array.

[0133] The electrode conversion module is characterized by using a programmable electrode conversion switch to switch the circuit, being equipped with a centralized switch, and using coding technology to control the switching of the conversion switch, so that the electrode conversion is automatically carried out according to the sequence and mode set by the program.

[0134] The data acquisition module collects the voltage difference across the electrode array, converts it into apparent resistivity, and stores it as data. Its main components include a Hall current sensor, an amplifier circuit, a filter, a multi-channel analog switch, a sample / hold circuit, a D / A converter, a computer I / O interface, and timing and control logic circuits. The Hall current sensor measures current and voltage in real time, collects the voltage difference, and converts it into a digital signal. The amplifier circuit amplifies and buffers the digital signal. The filter attenuates noise and improves the signal-to-noise ratio. The digital signal is amplified and buffered by the amplifier circuit, and then passes through the filter to improve the signal-to-noise ratio. The multi-channel analog switch selects the desired input channel to improve efficiency. The sample / hold circuit stabilizes the sampled signal. The D / A converter converts the output digital signal into an analog signal. The computer I / O interface handles data input and output. The timing and control logic circuits serve as the control center, ensuring the efficient operation of the components.

[0135] The data transmission module adopts a wireless data transmission module, which uses DSP technology and radio technology to transmit data.

[0136] 3. The electrode array features include two parts: a running electrode device and an electrode arrangement device, as follows:

[0137] The running electrode device is a device that runs in a specific running electrode mode. The electrode placement position of the present invention is the river bottom. The type of running electrode device is selected with high requirements for horizontal resolution and low requirements for vertical resolution. A dipole-dipole device is used. Figure 2 As shown, the specific running method of the dipole-dipole device is as follows: the power electrodes are A and B, and the receiving electrodes are M and N. The electrodes are arranged in the order of A, B, M, and N, with AB = MN. The observation point is the midpoint of the BM, and the BM distance is an integer multiple of the distance between AB or MN. When the dipole-dipole device begins to collect the voltage difference (between B and M), the power electrodes A and B remain in the same position, while the receiving electrodes M and N move away from the power electrodes A and B. Each time the electrode distance is changed, the observation point also moves with each change in the BM midpoint. This is done to collect data points with different isolation coefficients n. After a round of collection, that is, when electrodes M and N have moved to the farthest distance and data corresponding to different isolation coefficients have been collected, the power electrodes A and B are moved right by one electrode distance, and electrodes M and N are repositioned adjacent to electrodes A and B. The electrodes are arranged in the order of A, B, M, and N. This process is repeated until all data points have been collected.

[0138] The electrode arrangement device is an electrode arrangement device for estuaries, see Figure 3 - Figure 6 The electrode arrangement device specifically includes a titanium alloy conductive electrode (1), an electrode connector (2), a centralized cable (3) and a fixing nail; the fixing nail includes a nail tail (7), a nail body (6) and a nail head; the nail head is provided with a streamlined protrusion structure (4), a streamlined groove (5), a snap structure (8) and a snap component (9). The titanium alloy conductive electrode (1) is made of titanium alloy material and is designed to have a streamlined appearance. It is directly connected to the centralized cable (3) through the electrode connector (2). The outer layer of the centralized cable (3) and the electrode connector (2) are both wrapped with polyurethane material. The fixing nail is made of engineering plastic, the nail tail (7) is in the shape of a diamond spike, the nail body (6) is in the shape of a cone, the upper part is the nail head, and the middle of the nail head is a streamlined groove (5) that can be used to place the titanium alloy conductive electrode (1). The same streamlined protrusion structure (4) is provided on both sides of the nail head. The middle part of the top of the streamlined protrusion structure (4) is provided with a snap structure (8). The titanium alloy conductive electrode (1), the electrode connector (2), and the centralized cable (3) that are connected to each other are fixed on the fixing nail through the snap structure (8) and the snap component (9).

[0139] 4. Image reconstruction is characterized by its mathematical foundations in Radon transforms and inverse transforms, and its physical basis in quasi-steady field theory. Commonly used algorithms for image reconstruction include linear back-projection, the improved Newton-Raphson algorithm, and the improved Landweber pre-iteration algorithm. The linear back-projection algorithm is simple, computationally inefficient, and offers fast image reconstruction speed, making it ideal for qualitative analysis of rapid dynamic processes. Real-time monitoring of saltwater tides requires high image reconstruction speed, so the linear back-projection algorithm is considered for image reconstruction. Furthermore, to improve the accuracy of the reconstructed image using the linear back-projection algorithm, a back-projection weighting matrix can be introduced to filter the voltage at the boundary of the sensitive field before image reconstruction using the back-projection algorithm.

[0140] The estuary is monitored using the real-time saltwater tide monitoring device based on electrical resistance tomography provided by the second embodiment of the present invention. The principle is basically the same as that of the conventional resistivity method. Figure 7 As shown, placing the electrodes at the bottom of the estuary and ensuring good contact with the river water, and applying direct current using a suitable power supply can form a stable electric field.

[0141]

[0142]

[0143] In the above expressions (1) and (2), ρ is the apparent resistivity (Ω·m), I is the supply current between AB (A), ΔV is the observed potential difference between MN (V), K is the device coefficient (m), and AM, AN, BM, and BN are the distances between the corresponding electrodes, respectively.

[0144] Since seawater has a high ion concentration, good electrical conductivity, and lower resistivity than freshwater at the estuary, electrical resistance tomography (ERT) technology, based on the different resistivities of electric field media, can accurately distinguish saltwater at the estuary. The measured data can also be inverted using algorithms to obtain a resistivity distribution map of the two-dimensional section of the estuary, yielding intuitive real-time monitoring results.

[0145] The steps for monitoring an estuary using the real-time saltwater tide monitoring device based on electrical resistance tomography provided by the second embodiment of the present invention are as follows:

[0146] Step A: Select monitoring points. Conduct a field survey at the monitoring estuary and choose the survey line location and monitoring points. The distance between monitoring points should be selected according to the electrode spacing, which should not be greater than 10m. The riverbed soil at the selected location should be relatively hard and the surrounding disturbance should be small.

[0147] Step B: insert the fixing nail into the riverbed soil layer of the selected monitoring point, and completely insert the nail body (6) and the nail tail (7) into the layer to ensure that the nail head is exposed, and ensure that the streamline direction of the nail head, that is, the streamline direction of the streamlined convex structure, is consistent with the direction of water flow; if the soil layer of the selected monitoring point is not hard enough, a concrete block can be poured in advance, and the fixing nail is inserted into the concrete block with the nail head exposed, and then the concrete block is placed at the monitoring point to ensure that the streamline direction of the nail head, that is, the streamline direction of the streamlined convex structure, is consistent with the direction of water flow.

[0148] Step C: Fix the electrode connectors (2) at both ends of the conductive electrode (1) to the clips of the nail head. The specific fixing method is to press the two ends of the electrode connector (2) into the clip structure (8) with a certain elasticity, so that the titanium alloy conductive electrode (1) is placed on the outflow side of the streamlined groove (5) along the water flow direction, and then fill the side of the clip component (9). It is necessary to ensure that the electrode will not be covered by foreign matter. If necessary, protection can be set in front of the electrode to prevent it from being covered by foreign matter.

[0149] Step D: Arrange the power supply, connect the solar panels, batteries and charge controller, and then place the solar panels in a convenient and suitable sunny location. At the same time, if the ground temperature at the placement location is high, the solar panels can be placed on a special rack before placement.

[0150] Step E: Connect the corresponding components, connect the power supply, cables and host and complete the relevant debugging, and adjust the output voltage below 36V.

[0151] Step F: Set the host operating parameters, including minimum voltage, minimum resistance, maximum repeatability error, minimum apparent resistivity, etc. Turn on the power switch to output the excitation current to the electrode array. After the stable electric field is stimulated, that is, the voltage difference between the electrodes is basically stable, start automatic data collection.

[0152] Step G: The data is transmitted to the computer in real time through the data transmission module, and the linear back-projection algorithm is used to reconstruct and display the image. The specific process is as follows: the measurement field is divided into a limited number of units according to a certain division principle, and after generating the projection domain equipotential line coverage matrix and determining the equipotential line area corresponding to each unit, the voltage measurement data is input, and after filtering the voltage value, the back-projection algorithm is used to realize back-projection imaging and display it in the form of an image.

[0153] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A real-time monitoring method for estuarine saltwater tide based on electrical resistance tomography, characterized in that: include: Outputting an excitation current to the electrode array of the area to be monitored to stimulate the electric field of the electrode array; After the electric field of the electrode array is stabilized, the supply current of the electrode array and the voltage difference are collected; Calculating the apparent resistivity of the electrode array based on the supplied current and the observed voltage difference of the electrode array; According to the apparent resistivity of the electrode array, a linear back-projection algorithm is used to perform image reconstruction to obtain a resistivity distribution map to monitor the two-dimensional cross-sectional characteristics of the estuary saltwater tide in real time; The supply current and observed voltage difference of the acquisition electrode array are specifically: A fixed electrode device is used to fix a plurality of electrodes in the area to be monitored to form an electrode array; A first power supply electrode, a second power supply electrode, a first receiving electrode, and a second receiving electrode are arranged on the same straight line perpendicular to the direction of water flow in the area to be monitored, and the distance between the first power supply electrode and the second power supply electrode is controlled to be one electrode distance, the distance between the first receiving electrode and the second receiving electrode is controlled to be one electrode distance, and the distance between the second power supply electrode and the first receiving electrode is controlled to be a plurality of electrode distances; wherein the value of one electrode distance is set in advance; changing the electrode positions corresponding to the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode according to a preset running electrode method, and collecting the supply current between the first power supply electrode and the second power supply electrode and the observed voltage difference between the first receiving electrode and the second receiving electrode after each electrode position change; Determine that the collected supply current between all first power supply electrodes and second power supply electrodes is the supply current of the electrode array, and the collected observation voltage difference between all first receiving electrodes and second receiving electrodes is the observation voltage difference of the electrode array; The fixed electrode device is used to fix the electrodes in the electrode array and control the direction of the electrodes in the electrode array to be the same as the direction of water flow in the area to be monitored, specifically: The fixed electrode device includes an electrode connector, a cable and a fixing nail; The electrode connector is used to connect the electrode and the cable; The fixing nail is composed of a nail head, a nail body and a nail tail; Wherein, a streamlined groove is provided in the middle of the nail head, and the streamlined groove is used to place the electrode; The same streamlined protrusion structure is provided on both sides of the nail head, and a buckle structure and a buckle component are provided on the top middle part of the streamlined protrusion structure, and the buckle structure and the buckle component are used to fix the interconnected electrodes and cables on the fixing nail; By controlling the streamline direction of the streamlined protruding structure of the nail head to be consistent with the direction of water flow, the direction of the electrodes in the electrode array is controlled to be consistent with the direction of water flow in the area to be monitored.

2. The method for real-time monitoring of estuary saltwater tide based on electrical resistance tomography according to claim 1, wherein: The apparent resistivity of the electrode array is calculated based on the supply current and the observed voltage difference of the electrode array, specifically: Calculating a device coefficient of the electrode array according to the distances between the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode; The device coefficient of the electrode array is specifically: Wherein, AM is the distance between the first power supply electrode and the first receiving electrode; AN is the distance between the first power supply electrode and the second receiving electrode; BM is the distance between the second power supply electrode and the first receiving electrode; BN is the distance between the second power supply electrode and the second receiving electrode; K is the device coefficient of the electrode array; Calculating the apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode according to the device coefficient of the electrode array, the supply current of the electrode array and the observed voltage difference of the electrode array; The apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode is specifically: Wherein, ρ is the apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode; K is the device coefficient of the electrode array; ΔV is the observed voltage difference of the electrode array; I is the supply current of the electrode array; The apparent resistivity of the midpoint between the second power supply electrode and the first receiving electrode is determined as the apparent resistivity of the electrode array.

3. The method for real-time monitoring of estuary saltwater tide based on electrical resistance tomography according to claim 1, wherein: The image reconstruction is performed using a linear back-projection algorithm according to the apparent resistivity of the electrode array, specifically: Transmitting the apparent resistivity to a computer by means of DSP technology and radio technology; filtering the apparent resistivity using a back-projection weighted matrix to obtain data to be reconstructed; Image reconstruction is performed using a linear back-projection algorithm based on the data to be reconstructed.

4. The method for real-time monitoring of estuary saltwater tide based on electrical resistance tomography according to claim 1, wherein: The electric field of the electrode array is stable, specifically: After outputting the excitation current to the electrode array, the voltage difference between any two electrodes in the electrode array is detected in real time; If the voltage difference between any two electrodes is within a preset voltage range within a preset time period, it is determined that the electric field of the current electrode array is stable.

5. The method for real-time monitoring of estuary saltwater tide based on electrical resistance tomography according to claim 1, wherein: The excitation current is specifically: Convert the input current into a DC current with adjustable voltage; The DC current of the adjustable voltage is determined to be the excitation current.

6. A real-time monitoring system for estuary saltwater tide based on electrical resistance tomography, characterized in that: include: Excitation module, acquisition module, calculation module and reconstruction module; The excitation module is used to output an excitation current to the electrode array of the area to be monitored to excite the electric field of the electrode array; The acquisition module is used to collect the supply current and observe the voltage difference of the electrode array after the electric field of the electrode array is stabilized; The calculation module is used to calculate the apparent resistivity of the electrode array based on the supply current and the observed voltage difference of the electrode array; The reconstruction module is used to perform image reconstruction using a linear back-projection algorithm based on the apparent resistivity of the electrode array to obtain a resistivity distribution map to monitor the two-dimensional cross-sectional characteristics of the estuary saltwater tide in real time; The supply current and observed voltage difference of the acquisition electrode array are specifically: A fixed electrode device is used to fix a plurality of electrodes in the area to be monitored to form an electrode array; A first power supply electrode, a second power supply electrode, a first receiving electrode, and a second receiving electrode are arranged on the same straight line perpendicular to the direction of water flow in the area to be monitored, and the distance between the first power supply electrode and the second power supply electrode is controlled to be one electrode distance, the distance between the first receiving electrode and the second receiving electrode is controlled to be one electrode distance, and the distance between the second power supply electrode and the first receiving electrode is controlled to be a plurality of electrode distances; wherein the value of one electrode distance is set in advance; changing the electrode positions corresponding to the first power supply electrode, the second power supply electrode, the first receiving electrode, and the second receiving electrode according to a preset running electrode method, and collecting the supply current between the first power supply electrode and the second power supply electrode and the observed voltage difference between the first receiving electrode and the second receiving electrode after each electrode position change; Determine that the collected supply current between all first power supply electrodes and second power supply electrodes is the supply current of the electrode array, and the collected observation voltage difference between all first receiving electrodes and second receiving electrodes is the observation voltage difference of the electrode array; The fixed electrode device is used to fix the electrodes in the electrode array and control the direction of the electrodes in the electrode array to be the same as the direction of water flow in the area to be monitored, specifically: The fixed electrode device includes an electrode connector, a cable and a fixing nail; The electrode connector is used to connect the electrode and the cable; The fixing nail is composed of a nail head, a nail body and a nail tail; Wherein, a streamlined groove is provided in the middle of the nail head, and the streamlined groove is used to place the electrode; The same streamlined protrusion structure is provided on both sides of the nail head, and a buckle structure and a buckle component are provided on the top middle part of the streamlined protrusion structure, and the buckle structure and the buckle component are used to fix the interconnected electrodes and cables on the fixing nail; By controlling the streamline direction of the streamlined protruding structure of the nail head to be consistent with the direction of water flow, the direction of the electrodes in the electrode array is controlled to be consistent with the direction of water flow in the area to be monitored.

7. The real-time monitoring device for estuary saltwater tide based on electrical resistance tomography according to claim 6, characterized in that: The reconstruction module includes: a transmission unit, an acquisition unit and a reconstruction unit; The transmission unit is used to transmit the apparent resistivity to a computer by means of DSP technology and radio technology; The acquisition unit is used to filter the apparent resistivity using a back-projection weighted matrix to obtain data to be reconstructed; The reconstruction unit is used to perform image reconstruction using a linear back-projection algorithm based on the data to be reconstructed.

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