A SAR ocean internal wave amplitude inversion method and system with motion information constraints

Abstract

The present invention discloses a SAR ocean internal wave amplitude inversion method and system constrained by motion information, which belongs to the field of synthetic aperture radar signal processing and the field of ocean remote sensing application technology. The method comprises obtaining and preprocessing time series SAR images with clear wave characteristics in the study area; extracting the internal wave phase velocity from the preprocessed time series SAR images; selecting a SAR image profile that passes through the internal wave and is perpendicular to the wave crest line, and calculating the internal wave peak-to-peak distance; determining the possible interval of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance; and finding the best fit between the SAR image profile and the theoretical profile to determine the internal wave amplitude and the upper layer depth. The present invention improves the robustness of the internal wave amplitude inversion and provides support for the engineering application of SAR ocean internal wave amplitude inversion.

Description

Technical Field

[0001] The present invention belongs to the field of synthetic aperture radar (SAR) signal processing and ocean remote sensing application, and specifically relates to a motion information constrained SAR ocean internal wave amplitude inversion method and system. Background Art

[0002] Internal waves are large-amplitude vertical fluctuations generated in the ocean, which pose a serious threat to submarine navigation and oil drilling platforms. The generation mechanism of internal waves is very complex, and their temporal and spatial distribution is random. Therefore, internal wave detection and parameter inversion have become cutting-edge research topics in the ocean field.

[0003] Synthetic Aperture Radar (SAR) has the advantages of all-day, all-weather, long-distance, large-scale, and high-resolution, providing a rich source of data for internal wave detection and becoming an important remote sensing means for ocean internal wave observation. The basic horizontal parameters of internal waves (such as propagation direction, crest length, wavelength, phase velocity, etc.) can be directly determined from single or time-series SAR images, while the internal wave amplitude, as a vertical parameter, is the key to understanding the evolution, energy, and mixing processes of internal waves.

[0004] At present, the inversion of ocean internal wave amplitude based on SAR images is mainly divided into two categories: one is to invert the internal wave amplitude based on the relationship between the peak-to-peak distance extracted from the SAR image and the half-width of the internal wave characteristics, that is, first extract the peak-to-peak distance between the positive peak and the negative peak of the internal wave profile on the SAR image, and then combine the water depth, stratification, density and internal wave equation to invert the internal wave amplitude, phase velocity and other parameter information. The other is to extract the internal wave phase velocity based on the time series SAR image, and then invert the internal wave amplitude through the best fit between the theoretical model curve and the observation curve.

[0005] However, the accuracy of SAR ocean internal wave amplitude inversion is seriously affected by hydrological data such as upper depth. Due to the lack of on-site hydrological measurement data that matches the SAR image in time and space, most existing methods rely on historical hydrological data to invert the internal wave amplitude. However, the accuracy of historical hydrological data is not ideal, which brings errors to the internal wave amplitude inversion. In addition, the SAR image ocean internal wave amplitude inversion method has poor robustness. The peak-to-peak distance and half-width of the internal wave characteristics of the SAR image are easily disturbed by noise and other ocean phenomena. In the second type of method that highly relies on the internal wave phase velocity to invert the internal wave amplitude, the internal wave phase velocity has a great influence on the internal wave amplitude, which easily leads to unstable amplitude inversion results, poor anti-interference ability, and unreliable amplitude inversion results.

[0006] Therefore, in order to improve the accuracy and robustness of SAR ocean internal wave amplitude inversion, the existing methods need to be improved. Summary of the invention

[0007] To solve the above technical problems, the present invention provides a motion information constrained SAR ocean internal wave amplitude inversion method and system, which combines the internal wave motion information with the peak-to-peak distance of the internal wave SAR image to carry out internal wave amplitude inversion, thereby solving the problems of high error and poor robustness of SAR internal wave amplitude inversion in the prior art.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A SAR ocean internal wave amplitude inversion method with motion information constraint comprises the following steps:

[0010] Step 1: Obtain and preprocess time series SAR images with clear wave characteristics in the study area;

[0011] Step 2, extracting the internal wave phase velocity from the preprocessed time series SAR image;

[0012] Step 3, select the SAR image section that passes through the internal wave and is perpendicular to the wave crest line, and calculate the internal wave peak-to-peak distance;

[0013] Step 4: Determine the possible range of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance;

[0014] Step 5: Find the best fit between the SAR image profile and the theoretical profile to determine the internal wave amplitude and upper layer depth.

[0015] In another aspect, the present invention provides a SAR ocean internal wave amplitude inversion system with motion information constraint, comprising:

[0016] SAR image preprocessing module: used to obtain and preprocess time series SAR images with clear wave features in the study area;

[0017] Internal wave phase velocity extraction module, used to extract internal wave phase velocity from preprocessed time series SAR images;

[0018] The internal wave peak-to-peak distance calculation module is used to select the SAR image section passing through the internal wave and perpendicular to the wave crest line to calculate the internal wave peak-to-peak distance;

[0019] An internal wave amplitude interval setting module is used to determine the possible interval of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance;

[0020] The internal wave amplitude determination module is used to determine the internal wave amplitude and upper layer depth by finding the best fit between the SAR image profile and the theoretical profile.

[0021] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned motion information constrained SAR ocean internal wave amplitude inversion method.

[0022] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned SAR ocean internal wave amplitude inversion method constrained by motion information.

[0023] The beneficial effects of the present invention are:

[0024] The present invention starts from SAR ocean internal wave amplitude inversion, makes full use of the internal wave characteristics in SAR images and the correlation information in time series SAR images, and obtains the internal wave phase velocity. The introduction of the internal wave phase velocity reduces the internal wave amplitude inversion error caused by inaccurate hydrological data, improves the accuracy and robustness of the internal wave amplitude inversion, and provides support for the engineering application of SAR ocean internal wave amplitude inversion; at the same time, the introduction of the internal wave phase velocity also solves the double solution problem of the internal wave amplitude under the observed single peak-to-peak distance; the final upper layer depth is determined by the best fitting of the SAR image profile and the theoretical profile, and the influence of the hydrological data on the internal wave amplitude inversion result is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a motion information constrained SAR ocean internal wave amplitude inversion method of the present invention;

[0026] Figure 2 This is a schematic diagram of the implementation of a motion information constrained SAR ocean internal wave amplitude inversion method of the present invention;

[0027] Figure 3 A schematic diagram of capturing an internal wave region of interest according to an embodiment of the present invention, wherein (a) is the first SAR image in the time series SAR images, and (b) is the second SAR image in the time series SAR images;

[0028] Figure 4 A schematic diagram of the internal wave phase velocity distribution calculated by an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of radar backscatter coefficient distribution according to an embodiment of the present invention;

[0030] Figure 6 (a) shows the variation curve of internal wave amplitude with peak-to-peak distance;

[0031] Figure 6 (b) shows the curve of the internal wave amplitude changing with the internal wave phase velocity;

[0032] Figure 7 Schematic diagram of SAR image profile and theoretical profile. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0034] like Figure 1 As shown, the present invention provides a SAR ocean internal wave amplitude inversion method with motion information constraint, which improves the prior art mainly in the following aspects:

[0035] The present invention is based on time series SAR images and automatically extracts the internal wave phase velocity by tracking the movement of internal wave features in the time series SAR images. When the internal wave movement direction is inconsistent with the internal wave normal direction due to interference from other ocean phenomena, the velocity component in the internal wave normal direction is taken as the internal wave phase velocity.

[0036] The present invention obtains the expression of the internal wave amplitude with respect to the internal wave peak-to-peak distance based on the theory of high-order KdV equation, plots the variation curve of the internal wave amplitude with the peak-to-peak distance, and solves the double solution problem of the internal wave amplitude under the observed single peak-to-peak distance by introducing the internal wave phase velocity.

[0037] The present invention uses time series SAR images to extract internal wave phase velocity, and draws the curve of internal wave amplitude changing with internal wave phase velocity based on the high-order KdV equation theory, and determines the unique solution of internal wave amplitude by using the peak-to-peak distance obtained by the SAR image profile. The introduction of the internal wave peak-to-peak distance reduces the sensitivity of the internal wave amplitude to the phase velocity, and ensures the stability when using the phase velocity to invert the internal wave amplitude.

[0038] Since hydrological parameters such as the upper layer depth will affect the inversion results of the internal wave amplitude, the present invention determines the variation range of the upper layer depth with the estimated upper layer depth as the center, and determines the variation range of the internal wave amplitude with the unique solution of the internal wave amplitude determined by combining the internal wave peak-to-peak distance and the phase velocity as the center, and finds the optimal parameter combination of the internal wave amplitude and the upper layer depth by traversing the possible intervals.

[0039] Specifically, the method comprises the following steps:

[0040] Step 1: Obtain and preprocess time series SAR images with clear wave characteristics in the study area;

[0041] Step 2, extracting the internal wave phase velocity from the preprocessed time series SAR image;

[0042] Step 3, select the SAR image section that passes through the internal wave and is perpendicular to the wave crest line, and calculate the internal wave peak-to-peak distance;

[0043] Step 4: Determine the possible range of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance;

[0044] Step 5: Find the best fit between the SAR image profile and the theoretical profile to determine the internal wave amplitude and upper layer depth.

[0045] In some embodiments, at least two time-series SAR images are acquired as a first SAR image and a second SAR image, wherein the time-series SAR images contain the same group of internal wave features, and the time interval of the time-series SAR images is less than the decorrelation time of the internal wave features, and the time-series SAR images are preprocessed, such as filtering and registration. Since the internal wave features in SAR images are easily disturbed by ocean phenomena such as sea waves, before extracting the internal wave phase velocity by tracking the internal wave features in the time-series images, frequency domain filtering is required to eliminate the influence of the wave texture on the internal wave features. The preprocessed time-series SAR images are used for subsequent internal wave amplitude inversion, and the implementation flowchart is as follows: Figure 2 shown.

[0046] At present, the ocean internal wave amplitude inversion method based on SAR images is mainly based on the KdV equation theory. Studies have shown that the higher-order KdV equation can more accurately describe the nonlinear propagation process of internal waves than the KdV equation. The internal wave phase velocity is an important parameter in the higher-order KdV equation theory and can be obtained from time-series SAR images. The same internal wave region of interest is intercepted in the preprocessed time-series SAR images, and the internal wave phase velocity is calculated by tracking the movement of the internal wave features in the time-series SAR images using the maximum cross-correlation method. It is mainly divided into the following steps:

[0047] The first SAR image in the time series SAR image is divided into several template windows, and any template window in the internal wave area is selected. , different template windows There is some overlap between them. Template Window In the time series SAR images, the search area of ​​the second SAR image is selected for matching and the correlation coefficient is calculated. , the calculation formula is as follows:

[0048] (1)

[0049] in, represents the covariance, represents the variance, Represents the template window The corresponding search subwindow in the search area of ​​the second SAR image is, For the template window The center pixel coordinates of and Respectively represent the displacement of the center of the search subwindow relative to the center of the search area in the range and azimuth directions;

[0050] Get the template window The center pixel coordinates of The maximum value in the correlation coefficient matrix corresponding to the template window of the central pixel , according to the maximum value The internal wave velocity vector is estimated by the position offset relative to the center point:

[0051] (2)

[0052] in, is the time interval of the time series SAR images, and are the pixel spacing of the SAR image in the range and azimuth directions, is the calculated internal wave phase velocity, and They are the template windows for obtaining the maximum correlation coefficient. The number of pixels moved rightward and downward in the search area;

[0053] The next template window of the internal wave area is selected to repeat the internal wave phase velocity estimation operation until all template windows of the internal wave area of ​​interest in the first SAR image are traversed, that is, the ocean internal wave phase velocity of the time series SAR image is obtained. Among them, when the direction of internal wave motion is inconsistent with the direction of the internal wave normal due to interference from other ocean phenomena, the velocity component in the direction of the internal wave normal is taken as the internal wave phase velocity.

[0054] The peak-to-peak distance of internal waves refers to the distance between the bright and dark stripes of internal waves in SAR images, and is an important parameter for SAR internal wave amplitude inversion. In any SAR image, a SAR image section that passes through the internal wave and is perpendicular to the internal wave crest line is selected to obtain the horizontal distribution curve of the radar backscatter signal in the internal wave area. The peak-to-peak distance of internal waves in the SAR image is obtained by measuring the horizontal spacing between the positive and negative peak positions of the internal wave.

[0055] In order to determine the possible range of internal wave amplitude by combining the internal wave phase velocity and peak-to-peak distance, it is necessary to obtain the hydrological data of the study area, such as water depth, upper layer depth, density, etc., and substitute them into the high-order KdV equation to obtain the variation curve of internal wave amplitude with peak-to-peak distance and phase velocity. It is mainly divided into the following steps:

[0056] Obtain temperature and salinity profile data of the study area, substitute them into the thermodynamic equation of seawater, calculate density and buoyancy frequency; under the assumption of a two-layer fluid model, estimate the depth of the upper layer of seawater according to the maximum buoyancy frequency method , get the upper layer density according to the density profile , lower layer density , obtain the water depth of the study area through nautical chart data ; Calculate the internal wave linear phase velocity and parameters of the higher-order KdV equation , and The solitary wave solutions of the high-order KdV equation can be expressed in many forms, one of which is:

[0057] (3)

[0058] In the formula, is the vertical displacement of the two-layer fluid interface relative to the equilibrium position caused by a single soliton, Represents the horizontal coordinate, where the calculation expressions of the intermediate parameters are as follows:

[0059] (4)

[0060] (5)

[0061] (6)

[0062] in, represents the internal wave amplitude. Formula (4) can be used to plot the relationship between the internal wave amplitude and the internal wave phase velocity.

[0063] Since the internal wave amplitude is sensitive to the change of phase velocity, in order to obtain the accurate internal wave amplitude, it is also necessary to draw the curve of the change of internal wave amplitude with the internal wave peak-to-peak distance. The expression of the internal wave backscattering coefficient of the SAR image derived based on the high-order KdV equation is as follows:

[0064] (7)

[0065] Among them, the intermediate parameters , Indicates time, represents the angle of incidence, represents the radar wave number, represents the Bragg wave number on the sea surface, represents the polarization of the incident wave, represents the polarization of backscatter, The incident angle is The radar backscatter coefficient at time , represents the modulo operation, represents the first mode structure function, represents the Bragg wave angular frequency, represents a constant, represents the viewing angle of the radar beam relative to the wave direction, , represents the intermediate parameter, Indicates the vertical coordinate;

[0066] The peak position of the internal wave-induced radar backscatter coefficient deviating from its equilibrium value satisfies:

[0067] (8)

[0068] By solving formula (8), we can get the inner wave peak distance The expression is:

[0069] (9)

[0070] In the formula, and They represent the positions of the positive peak and negative peak of the internal wave respectively. Formula (9) is used to plot the relationship between the internal wave amplitude and the peak-to-peak distance.

[0071] According to the peak-to-peak distance of the internal wave obtained from the SAR image profile , determine two solutions of the internal wave amplitude from the curve of the change of the internal wave amplitude with the peak-to-peak distance, determine the unique solution of the internal wave amplitude according to the relationship curve of the internal wave amplitude with the internal wave phase velocity, and take the unique solution of the internal wave amplitude determined above as the center, and select the preset ranges on the left and right sides of the center as the possible interval of the internal wave amplitude.

[0072] The internal wave amplitude is traversed within the possible range of the internal wave amplitude, and the upper layer depth is traversed within the upper layer depth variation range determined with the estimated upper layer depth as the center. The final internal wave amplitude and upper layer depth are determined by finding the best fit between the observed SAR image profile and the theoretical profile.

[0073] Preferably, the filtering process of the time series SAR images can be implemented by using methods such as wavelet transform in addition to using frequency domain filtering to eliminate the influence of sea waves on internal wave characteristics.

[0074] Preferably, when obtaining the internal wave phase velocity from the time series SAR image, in addition to using the maximum cross-correlation method, methods such as the optical flow method can also be used.

[0075] The following is a further detailed description of a SAR ocean internal wave amplitude inversion method and system with motion information constraint proposed by the present invention through specific embodiments:

[0076] like Figure 2 As shown in Figure 1, first, this embodiment selects the Bay of Biscay as the research area. The tide in this area interacts with the shelf topography. Internal waves are generated at the break of the continental shelf and propagate on the continental shelf. The tidal current in this area has a stable semi-diurnal period, so the internal waves in this area are also called semi-diurnal internal tides. Download the time series SAR images of this area, perform registration and filtering, and intercept the internal wave area of ​​interest as shown in Figure 1. Figure 3 (a) and Figure 3As shown in (b), the SAR image has multiple groups of internal waves propagating toward the shore.

[0077] Using the preprocessed time series SAR images, the internal wave phase velocity is calculated by tracking the movement of the internal wave features in the time series SAR images according to formula (1) and formula (2). The internal wave phase velocity is obtained as follows: Figure 4 shown.

[0078] Select the SAR image section that passes through the internal wave and is perpendicular to the internal wave crest line (such as Figure 3 The radar backscatter coefficient distribution of this profile is shown as the white straight line in (a). Figure 5 As shown in the figure, the positions of the positive peak and negative peak of the internal wave and their corresponding backscattering coefficients are marked. By multiplying the position difference between the positive peak and the negative peak by the SAR image pixel interval, it can be obtained that the peak-to-peak distance of the internal wave is about 391m.

[0079] Then, the possible range of internal wave amplitude is determined by the internal wave phase velocity and peak-to-peak distance. First, the hydrological data of the World Ocean Atlas of the National Oceanic and Atmospheric Administration of the United States was downloaded, and the temperature and salinity data were input into the seawater thermodynamic equation to obtain the density and buoyancy frequency profiles. The upper and lower layer densities were calculated according to the density profile to be 1026.57 kg / m3 and 1027.38 kg / m3, respectively. The upper layer depth was estimated to be about 40m according to the buoyancy frequency profile. The nautical chart data of the Bay of Biscay was downloaded, and the water depth was about 153m. Substituting the above hydrological data into formula (9), the curves of the internal wave amplitude changing with the peak-to-peak distance under the KdV equation and the high-order KdV equation were plotted, as shown in Figure 6 (a), and two solutions of the internal wave amplitude when the internal wave peak-to-peak distance is 391m were found, which are -8m and -20m, respectively. Substituting the hydrological data into formula (4), the curves of the internal wave amplitude changing with the internal wave phase velocity under the KdV equation and the high-order KdV equation were plotted, as shown in Figure 6 (b). Find the solution of the internal wave amplitude when the internal wave phase velocity is about 0.54 m / s. As can be seen from Figure 6 (b), the internal wave amplitude is about -23 m, which is closer to the second solution of the internal wave amplitude (-20 m). Therefore, the possible interval of the internal wave amplitude is set to [-18 m, -25 m].

[0080] In the possible range of internal wave amplitude [-18m, -25m] and the range of upper layer depth variation [35m, 45m], the best fit between the SAR image profile and the theoretical profile is found by traversing the internal wave amplitude and the upper layer depth. When the internal wave amplitude is -20.5m and the upper layer depth is 44.5m, the mean square error between the SAR image profile and the theoretical profile is the smallest, which is about , the SAR image profile at this time is similar to the theoretical profile Figure 7 As shown, the internal wave amplitude inversion result at this time is taken as the final internal wave amplitude, and the SAR ocean internal wave amplitude inversion is completed.

[0081] On the other hand, the present invention provides a SAR ocean internal wave amplitude inversion system with motion information constraint, wherein each module included in the system can execute each step of the aforementioned method, specifically including:

[0082] SAR image preprocessing module: used to obtain and preprocess time series SAR images with clear wave features in the study area;

[0083] Internal wave phase velocity extraction module, used to extract internal wave phase velocity from preprocessed time series SAR images;

[0084] The internal wave peak-to-peak distance calculation module is used to select the SAR image section passing through the internal wave and perpendicular to the wave crest line to calculate the internal wave peak-to-peak distance;

[0085] An internal wave amplitude interval setting module is used to determine the possible interval of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance;

[0086] The internal wave amplitude determination module is used to determine the internal wave amplitude and upper layer depth by finding the best fit between the SAR image profile and the theoretical profile.

[0087] In a third aspect, the present invention provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned motion information constrained SAR ocean internal wave amplitude inversion method.

[0088] In a fourth aspect, the present invention provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, enables the processor to implement the aforementioned motion information constrained SAR ocean internal wave amplitude inversion method.

[0089] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A motion information constrained SAR ocean internal wave amplitude inversion method, characterized in that: The steps include: Step 1: Obtain and preprocess time series SAR images with clear wave characteristics in the study area; Step 2, extracting the internal wave phase velocity from the preprocessed time series SAR image; Step 3, select the SAR image section that passes through the internal wave and is perpendicular to the wave crest line, and calculate the internal wave peak-to-peak distance; Step 4: Determine the possible range of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance; Step 5, find the best fit between the SAR image profile and the theoretical profile to determine the internal wave amplitude and upper layer depth; Wherein, in step 2, the same internal wave region of interest is intercepted in the preprocessed time series SAR image, and the internal wave phase velocity is calculated by tracking the movement of the internal wave features in the time series SAR image using the maximum cross-correlation method, including: The first SAR image in the time series SAR image is divided into several template windows, and any template window in the internal wave area is selected. , Template Window In the time series SAR images, the search area of ​​the second SAR image is selected for matching and the correlation coefficient is calculated. , the calculation formula is as follows: （1） in, represents the calculation of covariance, represents the calculation of variance, Represents the template window The corresponding search subwindow in the search area of ​​the second SAR image is, For the template window The center pixel coordinates of and Respectively represent the displacement of the center of the search subwindow relative to the center of the search area in the range and azimuth directions; Get the template window The center pixel coordinates of The maximum value in the correlation coefficient matrix corresponding to the template window of the central pixel , according to the maximum value The internal wave phase velocity is estimated from the position offset relative to the center point: （2） in, is the time interval of the time series SAR images, and are the pixel spacing of the SAR image in the range and azimuth directions, is the calculated internal wave phase velocity, and They are the template windows for obtaining the maximum correlation coefficient. The number of pixels moved rightward and downward in the search area; The next template window of the internal wave area is selected to repeat the internal wave phase velocity estimation operation until all template windows of the internal wave area of ​​interest in the first SAR image are traversed, that is, the ocean internal wave phase velocity of the time series SAR image is obtained. Among them, when the direction of internal wave motion is inconsistent with the direction of the internal wave normal due to interference from other ocean phenomena, the velocity component in the direction of the internal wave normal is taken as the internal wave phase velocity.

2. The method for SAR ocean internal wave amplitude inversion with motion information constraint according to claim 1, characterized in that: In the step 1, the number of time series SAR images acquired is at least two, the time series SAR images contain the same group of internal wave features, and the time interval of the time series SAR images is less than the decorrelation time of the internal wave features.

3. The method for SAR ocean internal wave amplitude inversion with motion information constraint according to claim 2, characterized in that: In the step 1, preprocessing the time series SAR images includes registering the time series SAR images. When the time series SAR images are disturbed by sea waves, frequency domain filtering is performed to eliminate the influence of sea wave texture on internal wave characteristics.

4. The method for SAR ocean internal wave amplitude inversion with motion information constraint according to claim 3 is characterized in that: In step 3, a SAR image section passing through the internal wave and perpendicular to the internal wave crest line is selected in any SAR image to obtain a horizontal distribution curve of the radar backscattering coefficient in the internal wave area, and the internal wave peak-to-peak distance in the SAR image is obtained by measuring the horizontal spacing between the positive peak and the negative peak of the internal wave.

5. The method for SAR ocean internal wave amplitude inversion with motion information constraint according to claim 4, characterized in that: In step 4, based on the high-order KdV equation theory, a curve of the internal wave amplitude versus the internal wave phase velocity and the internal wave peak-to-peak distance is drawn, including: Obtain temperature and salinity profile data of the study area, substitute them into the thermodynamic equation of seawater, calculate density and buoyancy frequency; under the assumption of a two-layer fluid model, estimate the depth of the upper layer of seawater according to the maximum buoyancy frequency method , get the upper layer density according to the density profile , lower layer density , obtain the water depth of the study area through nautical chart data ; Calculate the internal wave linear phase velocity and parameters of the higher-order KdV equation , and , substitute into the relationship between internal wave phase velocity and internal wave amplitude: （4） in, represents the internal wave amplitude. The relationship curve between the internal wave amplitude and the internal wave phase velocity is plotted using the above formula (4). The expression of the internal wave backscattering coefficient of the SAR image derived based on the high-order KdV equation is as follows: （7） Among them, the intermediate parameters , intermediate parameter , Represents the horizontal coordinate, Indicates time, represents the angle of incidence, represents the radar wave number, represents the Bragg wave number on the sea surface, represents the polarization of the incident wave, represents the polarization of backscatter, The incident angle is The radar backscatter coefficient at time , represents the modulo operation, represents the first mode structure function, represents the Bragg wave angular frequency, represents a constant, represents the viewing angle of the radar beam relative to the wave direction, , represents the intermediate parameter, Indicates the vertical coordinate; The peak position of the internal wave-induced radar backscatter coefficient deviating from its equilibrium value satisfies: （8） By solving the above formula (8), we can get the inner wave peak distance The expression is: （9） In the formula, and They represent the positions of the positive peak and negative peak of the internal wave respectively. The above formula (9) is used to plot the variation curve of the internal wave amplitude with the peak-to-peak distance.

6. The method for SAR ocean internal wave amplitude inversion with motion information constraint according to claim 5, characterized in that: In step 4, the peak-to-peak distance of the inner wave obtained from the SAR image profile is , determine two solutions of the internal wave amplitude from the curve of the change of the internal wave amplitude with the peak-to-peak distance, determine the unique solution of the internal wave amplitude according to the relationship curve of the internal wave amplitude with the internal wave phase velocity, take the currently determined unique solution of the internal wave amplitude as the center, and select the preset ranges on the left and right sides of the center as the possible interval of the internal wave amplitude; The internal wave amplitude is traversed within the possible range of the internal wave amplitude, and the upper layer depth is traversed within the upper layer depth variation range determined with the estimated upper layer depth as the center. The final internal wave amplitude and upper layer depth are determined by finding the best fit between the observed SAR image profile and the theoretical profile.

7. A SAR ocean internal wave amplitude inversion system with motion information constraint, applied to the method according to any one of claims 1 to 6, characterized in that: include: SAR image preprocessing module: used to obtain and preprocess time series SAR images with clear wave features in the study area; Internal wave phase velocity extraction module, used to extract internal wave phase velocity from preprocessed time series SAR images; The internal wave peak-to-peak distance calculation module is used to select the SAR image section passing through the internal wave and perpendicular to the wave crest line to calculate the internal wave peak-to-peak distance; An internal wave amplitude interval setting module is used to determine the possible interval of the internal wave amplitude by combining the internal wave phase velocity and the peak-to-peak distance; The internal wave amplitude determination module is used to determine the internal wave amplitude and upper layer depth by finding the best fit between the SAR image profile and the theoretical profile.

8. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; Wherein, when one or more programs are executed by the one or more processors, the one or more processors implement the motion information constrained SAR ocean internal wave amplitude inversion method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that: Executable instructions are stored thereon, and when the instructions are executed by a processor, the processor can implement a motion information constrained SAR ocean internal wave amplitude inversion method as described in any one of claims 1-6.

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