A method and device for monitoring bank slope deformation, and a storage medium

Abstract

This invention discloses a method, device, and storage medium for monitoring bank slope deformation, comprising: acquiring two images of the same area, a primary and a secondary image, using a SAR system during a single orbital run; performing image registration of the two images using a corner reflector; obtaining the interferometric deformation phase of the area with changing corner reflections from images at different time phases based on the image registration result; and simultaneously obtaining ground deformation information based on the interferometric deformation phase. Using the technical solution of this invention, deformation information along the banks of a reservoir can be obtained flexibly, conveniently, and quickly.

Description

Technical Field

[0001] This invention belongs to the field of environmental monitoring technology, and in particular relates to a method and system for monitoring bank slope deformation, and a storage medium. Background Technology

[0002] With economic and technological growth, numerous water conservancy facilities have been constructed for power generation, irrigation, and flood prevention. The construction of dams, which collect flowing water to form artificial lakes, can lead to changes in the land properties around reservoirs due to natural factors such as earthquakes and rainfall. This can potentially cause geological disasters like landslides and mudslides, endangering people's lives and livelihoods. Therefore, long-term, high-precision deformation monitoring of reservoir banks and other areas is crucial for early warning and prevention, enabling timely intervention and minimizing unnecessary losses.

[0003] For monitoring slope deformation, spaceborne SAR satellites are currently used for measurement. These satellites offer high precision, high efficiency, all-weather capability, and multi-functionality. They are simple to operate and can be automated to acquire deformation information, and can provide global or regional deformation monitoring networks, playing a significant role in geological disaster monitoring. However, GNSS technology acquires point-based surface information, which cannot reflect the overall displacement of the observed target. This technology is costly when acquiring large-scale, high-density deformation information, and its accuracy and reliability are limited along reservoir banks. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for monitoring bank slope deformation, and a storage medium, which can flexibly, conveniently and quickly acquire information on bank deformation along reservoirs.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for monitoring bank slope deformation includes the following steps:

[0007] Step S1: Use a SAR system to acquire two images of the same area, a primary and a secondary image, during a single orbital run;

[0008] Step S2: The SAR system uses a corner reflector to perform image registration on the primary and secondary images;

[0009] Step S3: The SAR system obtains the interferometric deformation phase of the region with changing angular reflection through images of different time phases based on the image registration results; at the same time, it obtains ground deformation information based on the interferometric deformation phase.

[0010] As a preferred method, the SAR system uses a multi-track movement mode to acquire two images of the same area, a primary and a secondary image.

[0011] Preferably, the registration in step S2 adopts the coherence coefficient method, and the registration result reaches the sub-pixel level through a hierarchical registration strategy.

[0012] Preferably, the SAR system is a vehicle-mounted InSAR system, which calculates ground deformation information by using a non-zero spatial baseline deformation monitoring model to measure the interferometric deformation phase.

[0013] Preferably, the SAR system is a shipborne InSAR system, which calculates ground deformation information by using the slant range difference of the shipborne dual-antenna InSAR mode to obtain the interferometric deformation phase.

[0014] The present invention also provides a shoreline slope deformation monitoring device, comprising:

[0015] The acquisition module is used to acquire two images of the same area, a primary and a secondary image, during a single orbital run using a SAR system.

[0016] The registration module is used by the SAR system to perform image registration on the primary and secondary images using corner reflectors;

[0017] The calculation module is used by the SAR system to obtain the interferometric deformation phase of the region with changing angular reflection from images at different time phases based on the image registration results; and to obtain ground deformation information based on the interferometric deformation phase.

[0018] Preferably, the acquisition module uses a SAR system to acquire two images of the same area, a primary and a secondary image, via a multi-track movement method.

[0019] As a preferred option, the registration module adopts the coherence coefficient method and uses a hierarchical registration strategy to achieve registration results at the sub-pixel level.

[0020] Preferably, the SAR system is a vehicle-mounted InSAR system, which calculates the interferometric deformation phase using a non-zero spatial baseline deformation monitoring model to obtain ground deformation information; or the SAR system is a ship-mounted InSAR system, which calculates the interferometric deformation phase using the slant range difference of the ship-mounted dual-antenna InSAR mode to obtain ground deformation information.

[0021] The present invention also includes a storage medium storing machine-executable instructions, which, when invoked and executed by a processor, cause the processor to implement the aforementioned method for monitoring bank slope deformation.

[0022] The shore slope deformation monitoring of this invention adopts the InSAR observation method based on a vehicle-to-ship mobile platform. Unlike the acquisition of spaceborne SAR data, the antenna depression angle is smaller when the vehicle-to-ship SAR image is used. At the reservoir side slope, there will be no overlapping phenomenon in the spaceborne SAR image data due to the large slope. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the method for monitoring bank slope deformation according to the present invention.

[0024] Figure 2 This is a schematic diagram of the "one-to-two" transmission and reception mode of the present invention;

[0025] Figure 3 This illustrates the geometric relationship between the transmit / receive antenna and the target point in this invention.

[0026] Figure 4 This describes the antenna position relationship between the actual and "ideal" scenarios in this invention.

[0027] Figure 5 This is a schematic diagram of the geometric imaging of the improved two-dimensional RD equation model of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Example 1:

[0030] like Figure 1 As shown, the present invention provides a method for monitoring bank slope deformation, comprising the following steps:

[0031] Step S1: Use a SAR system to acquire two images of the same area, a primary and a secondary image, during a single orbital run;

[0032] Step S2: The SAR system uses a corner reflector to perform image registration on the primary and secondary images;

[0033] Step S3: The SAR system obtains the interferometric deformation phase of the region with changing angular reflection through images of different time phases based on the image registration results; at the same time, it obtains ground deformation information based on the interferometric deformation phase.

[0034] As one implementation method of this embodiment, the SAR system uses a multi-track movement method to acquire two images of the same area, a primary and a secondary image.

[0035] As one implementation method of this embodiment, the registration in step S2 adopts the coherence coefficient method. Through the hierarchical registration strategy, the registration result reaches the sub-pixel level.

[0036] As one implementation method of this embodiment, the SAR system is a vehicle-mounted InSAR system. The vehicle-mounted InSAR system calculates the ground deformation information by means of an interferometric deformation phase using a non-zero spatial baseline deformation monitoring model. Specifically:

[0037] The imaging geometry of a SAR system is as follows: A small SAR system with a fixed baseline uses dual antennas to simultaneously transmit signal waves to a corner reflector. The echo information from both antennas is then received using only a single receiving antenna. After autofocusing, a SAR image of the corresponding test area is generated. Two echo signals are obtained from this image, one before and one after the corner reflector's height deformation. The orbital information at the time of image acquisition and the exterior orientation elements of the SAR sensor are acquired using a POS system. The phase of the interferometric value obtained after differential interferometry consists of two parts: the phase change caused by the corner reflector's deformation and the phase change caused by the fixed baseline offset. To obtain the final corner reflector deformation, the phase error caused by the fixed baseline offset must be eliminated, thus establishing a model of non-zero spatial baseline deformation.

[0038] According to the theory of electromagnetic wave propagation, when a SAR sensor images a corner reflector, the backscattered microwave echo information is affected by multiple factors. The complex signal u of a pixel in a SAR image can be expressed as:

[0039]

[0040] in, Here, λ is the phase value of the complex signal, u is the amplitude, r is the distance from the corner reflector to the SAR sensor, and λ is the wavelength. This is the contribution value of the target's scattering phase. Assuming that the scattering phase is the same on SAR images from different imaging orbits, the SAR interferogram can be obtained by multiplying the conjugates of two SAR images to obtain the interferometric phase. This can be considered as the Earth's flat phase. Terrain phase Deformation phase noise phase The total contribution value is then:

[0041]

[0042] in, and These are the phase values ​​of the complex signal from the two SAR images, where r1 and r2 represent the ground target ranges of the SAR sensor during the two acquisitions. Deformation phase. It is obtained from D-InSAR, topographic phase. This noise is caused by terrain and is related to the fixed baseline b, the offset B of the fixed baseline, and the relative height H0 between the SAR observation target and the reference plane. In this study, we can consider the noise to be randomly generated. Furthermore, since the vehicle-mounted small SAR acquires the corner reflector, the flat-ground phase can be eliminated after differential analysis. Therefore, we will not consider the influence of the flat-ground phase below. Solve the problem.

[0043] Since the fixed baseline b is much smaller than the observation distance R, and the fixed baseline is perpendicular to the plane where the observation point is located, then:

[0044] Δr=r1-r2≈bcosθ (3)

[0045] Differentiating the above equation yields:

[0046]

[0047] Substituting equation (4) into equation (2), we get:

[0048]

[0049] Differentiating both sides of the equation H = r1cosθ, we get:

[0050]

[0051] Substituting equation (6) into equation (5), we get:

[0052]

[0053]

[0054] Where b is the spatial baseline of the InSAR pair, H is the height image on the reference surface of the target when using the main SAR, θ is the angle between the antenna direction and the observation direction, and D is the displacement along the line of sight of the ground target from the SAR image acquisition period.

[0055] In equation (8), D is the value to be obtained by differential interferometry, and the two interference phases before and after deformation are obtained by dual-antenna interference.

[0056]

[0057] Where r1 and r3 are the distances between the antenna containing the main image and the imaging target when the two interferometric images are generated, respectively. The deformed D can be obtained from the above expression.

[0058]

[0059] In this formula, it is generally considered that the value of D0 is 0, that is, there is no deformation in the first dual-antenna observation data, so there is

[0060]

[0061] This formula (11) is the exact expression of the deformation amount in the slant range direction of the ground target point obtained after image differential interferometry. However, considering the problems of measurement accuracy and complex calculation of r1 and r3 in practical applications, and the fixed baseline offset B can be accurately obtained to the millimeter level according to the image POS data, so in this study, r1 / r3 is converted to the fixed baseline offset B for calculation, and then a fast calculation model is derived.

[0062] According to the sine theorem in the triangle formed by B, r1, and r2, there is:

[0063]

[0064] Then formula (11) can be transformed into

[0065]

[0066] Among them, θ is the viewing angle of the SAR master image to the target object. According to the triangular relationship, it can be known that:

[0067]

[0068] Among them, H is the relative elevation of the antenna where the master image is located during SAR imaging and the corner reflector, and d is the distance between the projection point of the antenna corresponding to the trajectory closer to the corner reflector on the plane where the corner reflector is located and the corner reflector.

[0069]

[0070] Since the fixed baseline offset B of the two trajectories << d, there is a Taylor expansion formula

[0071]

[0072] B is a small quantity relative to H 2 Then, by discarding the second-order high-order terms from the Taylor expansion formula, there is

[0073]

[0074] Substitute formula (17) into formula (15)

[0075]

[0076] Equation (11) is the precise mathematical model established in this paper, and Equation (18) is the rapid calculation mathematical model for deformation monitoring. The obtained D is the deformation of the ground target in the radar imaging line of sight. After angle transformation, the final ground deformation information in height can be obtained.

[0077]

[0078] As one implementation method of this embodiment, the SAR system is a shipborne InSAR system. The shipborne InSAR system calculates the ground deformation information by using the slant range difference of the shipborne dual-antenna InSAR mode to obtain the interferometric deformation phase. Specifically:

[0079] like Figure 2 As shown, the shipborne dual-antenna InSAR system is in "one transmit, two receive" mode, that is, the main antenna and the auxiliary antenna each consist of two ports. The auxiliary antenna transmits microwave signals through port 1, and the auxiliary antenna's port 2 and the main antenna's port 4 receive the echo signals scattered by ground objects, respectively.

[0080] Therefore, according to the principle of interferometric imaging, we have:

[0081]

[0082]

[0083] Furthermore, since the slant ranges obtained in the actual imaging process are M1_R and S1_R, their relationship with R1, R2, and R4 is as follows:

[0084]

[0085]

[0086] Substituting the above equation into (20) and (21), we get:

[0087]

[0088] The slope distance is calculated as follows under the "ideal" case:

[0089] The distances from the main antenna and the auxiliary antenna to the ground target are not equal. For the main antenna, its transmission and reception distances can be considered equal, and the one-way slant range r0 can be directly obtained from the SAR system's power-on time. However, the transmission and reception distances in the data received by the auxiliary antenna cannot be considered the same (otherwise, the distance between the main and auxiliary antennas would be 0). Figure 3In this diagram, S1 is the position of the transmitting antenna, S2 is the position of the receiving antenna, and T is the position of the ground target. Based on the system's startup time, only the average slant range can be obtained, i.e., r1 + r2 = 2r0, where r0 is the slant range acquired by the system, r1 is the transmitting slant range, and r2 is the receiving slant range. Assuming the working surface is flat, derive the theoretical values ​​of the transmitting slant range r1 and the receiving slant range r2. Let the vertical distance from the main antenna S1 to the ground be h1, the vertical distance from the auxiliary antenna S2 to the ground be h2, the baseline length of S1 and S2 be B, the baseline tilt angle be α, and the target point be T. Let the horizontal distance |OT| between the main antenna S1 and T be x1, and the horizontal distance |XT| between the auxiliary antenna S2 and T be x2. That is...

[0090]

[0091]

[0092] x1-x2=B cosα (26)

[0093] Substituting equations (24)-(26) into r1+r2=2r0 and eliminating x1, we obtain equation (27):

[0094]

[0095] Taking the second power of both sides of equation (27) simultaneously, we get equation (28):

[0096]

[0097] make Squaring both sides of equation (28) yields equation (29):

[0098]

[0099] Solving the quadratic equation with x2 as the parameter, we can obtain:

[0100]

[0101] Substituting (30) into (24), (25) and (26) will yield the values ​​of the compensated transmit slant range r1 and receive slant range r2.

[0102] The actual slope distance is calculated as follows: Figure 4 As shown:

[0103] In the actual data received by the main antenna, the transmission distance and the receiving distance can be approximated as equal. This is because the propagation speed of electromagnetic waves is approximately 3 × 10⁻⁶. 8Given that the speed is m / s and the distance between the shipborne antenna and the target point is at most 500m, the position of the main antenna in the preceding and following time phases can be approximated as unchanged. In other words, the position of the main antenna can be obtained by measurement, and the true slant range r can be directly calculated.

[0104] For the auxiliary antenna, since the POS system generally uses the antenna phase center of the main antenna as the reference point, the antenna attitude angle has a significant impact on the calculation of the actual transmit and receive slant range when calculating the data received by the auxiliary antenna, and must be taken into account in the calculation.

[0105] Based on the height h'1 of S′1, the horizontal distance x'1 from S′1 to the feature point T, the height h'2 of S′2, and the horizontal distance x'2 from S′2 to the feature point T, the true slope distance r'1 of S′1 and the true slope distance r'2 of S′2 are calculated.

[0106] The slant range difference of the main antenna is given by equation (31):

[0107] ΔR m =2(r-r0) (31)

[0108] The slant range difference of the auxiliary antenna is given by equation (32):

[0109] ΔR s =r′1-r1+r′2-r2 (32)

[0110] To more intuitively describe the relative relationship between the entire imaging system and the ground point, a two-dimensional rectangular coordinate system is established with the center of the main antenna S3 and the auxiliary antenna S4 in the dual antenna system during the second phase formation as the origin and the direction of the vector S4S3 as the y-axis, as shown below. Figure 5 As shown:

[0111] To simplify the calculation, we assume that S3, S4, P1, and P2 are on the same plane. Furthermore, to reduce the impact of non-coplanarity errors, S1 and S2 are not included in the calculation. Let d be the distance between S3 and S4, i.e., the antenna length.

[0112] First, calculate the coordinates of point P2. Since P2 lies on a circle with P3 as the origin and R3 as the radius,

[0113] (P2X-0) 2 +(P2Y-d / 2) 2 =R 31 2 (33)

[0114] Furthermore, P2 can be obtained by interference from dual antennas S3 and S4, according to the principle of interferometric imaging:

[0115]

[0116]

[0117] Combining (33), (34), and (35), and taking y < 0 and x > 0, we can obtain the coordinate expression of P2 as:

[0118]

[0119]

[0120] For point P1, substituting the coordinates (i, j) of P1 on the image into the antenna parameters of the second time phase allows us to calculate the distance R between P1 and S3 and S4. 31 R 41 Therefore, P1 is centered on S3, R 31 A circle with radius S4, and R centered at S4 41 At the intersection of circles with radius .

[0121] (P1X-0) 2 +(P1Y+d / 2) 2 =R 42 2

[0122] (P2X-0) 2 +(P2Y-d / 2) 2 =R 32 2 (37)

[0123] Let the solution where y < 0 and x > 0 be the value of P1:

[0124]

[0125]

[0126] Therefore, the ground deformation information D is:

[0127] D = (P1X - P2X) 2 +(P1Y-P2Y) 2 (39)

[0128] Example 2:

[0129] The present invention also provides a shoreline slope deformation monitoring device, comprising:

[0130] The acquisition module is used to acquire two images of the same area, a primary and a secondary image, during a single orbital run using a SAR system.

[0131] The registration module is used by the SAR system to perform image registration on the primary and secondary images using corner reflectors;

[0132] The calculation module is used by the SAR system to obtain the interferometric deformation phase of the region with changing angular reflection from images at different time phases based on the image registration results; and to obtain ground deformation information based on the interferometric deformation phase.

[0133] As one implementation method of this embodiment, the acquisition module acquires two images of the same area using a multi-track movement method through the SAR system.

[0134] As one implementation method of this embodiment, the registration module adopts the coherence coefficient method and uses a hierarchical registration strategy to achieve the registration result at the sub-pixel level.

[0135] In one embodiment of this invention, the SAR system is a vehicle-mounted InSAR system, which calculates the interferometric deformation phase using a non-zero spatial baseline deformation monitoring model to obtain ground deformation information; or the SAR system is a shipborne InSAR system, which calculates the interferometric deformation phase using the slant range difference of a shipborne dual-antenna InSAR mode to obtain ground deformation information.

[0136] Example 3:

[0137] The present invention also includes a storage medium storing machine-executable instructions, which, when invoked and executed by a processor, cause the processor to implement the aforementioned method for monitoring bank slope deformation.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for monitoring bank slope deformation, characterized in that, Includes the following steps: Step S1: Use a SAR system to acquire two images of the same area, a primary and a secondary image, during a single orbital run; Step S2: The SAR system uses a corner reflector to perform image registration on the primary and secondary images; Step S3: The SAR system obtains the interferometric deformation phase of the region with changing angular reflection from images of different time phases based on the image registration results; at the same time, it obtains ground deformation information based on the interferometric deformation phase. The SAR system uses a multi-track movement method to acquire two images, a primary and a secondary image, of the same area; The registration in step S2 adopts the coherence coefficient method. Through the hierarchical registration strategy, the registration result reaches the sub-pixel level. The SAR system is a vehicle-mounted InSAR system, which calculates the interferometric deformation phase using a non-zero spatial baseline deformation monitoring model to obtain ground deformation information; or the SAR system is a ship-mounted InSAR system, which calculates the interferometric deformation phase using the slant range difference of the ship-mounted dual-antenna InSAR mode to obtain ground deformation information.

2. A bank slope deformation monitoring device, characterized in that, include: The acquisition module is used to acquire two images of the same area, a primary and a secondary image, during a single orbital run using a SAR system. The registration module is used by the SAR system to perform image registration on the primary and secondary images using corner reflectors; The calculation module is used by the SAR system to obtain the interferometric deformation phase of the region with changing angular reflection from images at different time phases based on the image registration results; and to obtain ground deformation information based on the interferometric deformation phase. The acquisition module uses a multi-track movement method with the SAR system to acquire two images of the same area, one primary and one secondary. The registration module uses the coherence coefficient method and employs a hierarchical registration strategy to achieve sub-pixel level registration results. The SAR system is a vehicle-mounted InSAR system, which calculates the interferometric deformation phase using a non-zero spatial baseline deformation monitoring model to obtain ground deformation information; or the SAR system is a ship-mounted InSAR system, which calculates the interferometric deformation phase using the slant range difference of the ship-mounted dual-antenna InSAR mode to obtain ground deformation information.

3. A storage medium, characterized in that, The storage medium stores machine-executable instructions, which, when invoked and executed by a processor, cause the processor to implement the bank slope deformation monitoring method of claim 1.

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