Methods and systems for vortex center calibration, motion trajectory tracking in planar flow fields

Abstract

This invention provides a method, a motion trajectory tracking method, and a system for calibrating the center of a vortex in a planar flow field. It determines the sizes of a maximum and minimum value filter, as well as the DBSCAN clustering algorithm parameters, based on the characteristics of the planar vortex flow field. Local maxima are calculated using the maximum value filter, and local minima are calculated using the minimum value filter. The local maxima and minima are sorted to calculate preliminary marker points for the vortex center. These preliminary marker points are then clustered and merged according to the DBSCAN clustering algorithm parameters. The preliminary marker point with the highest intensity value in each cluster is designated as the vortex center location. This invention fully considers the complexity of the planar vortex flow field itself, as vortex sizes can vary significantly in different scenarios. By adaptively adjusting and setting the filter sizes and DBSCAN clustering algorithm parameters, and combining the preliminary marker points calculated by the filters with the clustering algorithm, accurate calibration of the vortex center location is achieved in different scenarios.

Description

Technical Field

[0001] This invention relates to the field of image processing technology, and in particular to a method for calibrating the center of a vortex in a planar flow field, a method for tracking motion trajectories, and a system thereof. Background Technology

[0002] The application background of planar flow field vortex center location calibration, cross-frame matching, and motion trajectory tracking is to track the generation, development, evolution, dissipation, and dissipation of aircraft wake vortices in the atmosphere. Aircraft wake vortices are a byproduct of lift generation and are characterized by their intensity, stability, and large spatial scale. During cruise and approach phases, due to the long residence time of aircraft wake vortices, when a following aircraft enters the wake region of a preceding aircraft, the strong vortex structure-induced rolling torque can cause the following aircraft to experience shaking, sinking, and changes in flight status, potentially leading to flight accidents. Due to interference from components such as control surfaces, flaps, spoilers, and landing gear, the two-dimensional cross-section of the aircraft wake region is a complex planar vortex flow field, encompassing vortex generation caused by disturbances, interactions between vortices, and the gradual weakening and eventual dissipation of already formed vortices due to air viscosity effects. In observing and tracking the formation, evolution, and dissipation of aircraft wake vortices in the atmosphere, vortex center location calibration, cross-frame matching, and motion trajectory tracking are essential. Summary of the Invention

[0003] Due to the inherent complexity of planar vortex flow fields, the size of vortexes can vary significantly in different scenarios, affecting the accuracy of vortex center calibration. Furthermore, vortex motion is constrained by overall flow characteristics (such as Reynolds number and external drive) and is also influenced by surrounding vortices in the flow field. Therefore, vortex motion trajectories exhibit significant randomness, making trajectory tracking difficult.

[0004] This invention was made in view of the aforementioned existing conditions, and its purpose is to provide a method for calibrating the center of a vortex in a planar flow field, a method for tracking its motion trajectory, and a system, so as to improve the calibration accuracy of the vortex center in a planar vortex flow field and achieve accurate tracking of the vortex motion trajectory. To achieve the above objective, the embodiments of this invention provide the following technical solutions:

[0005] This invention provides a method for calibrating the vortex center in a planar flow field, the method comprising:

[0006] Determine the sizes of the maximum and minimum value filters and the parameters of the DBSCAN clustering algorithm based on the characteristics of the planar vortex flow field.

[0007] The maximum value filter is used to calculate the local maxima of the vorticity value of the planar vortex flow field, and the minimum value filter is used to calculate the local minima of the vorticity value of the planar vortex flow field.

[0008] Based on the sorting of the local maxima and local minima, preliminary marker points for the vortex centers of the planar vortex flow field are determined.

[0009] The initial labeled points are clustered and merged according to the DBSCAN clustering algorithm parameters;

[0010] The initial marker point with the highest intensity value in each cluster is set as the vortex center position.

[0011] In this case, the complexity of the planar vortex flow field itself is fully considered. The vortex size will vary greatly in different scenarios. By adaptively adjusting and setting the filter size and DBSCAN clustering algorithm parameters, the preliminary marker points calculated by the filter are combined with the clustering algorithm to achieve accurate calibration of the vortex center position in different scenarios.

[0012] The maximum value filter and the minimum value filter both include an M×M pixel matrix, where M represents that the filter covers M pixels in each direction, and M depends on the average size of the vortex in the planar vortex flow field.

[0013] This avoids the same vortex being marked multiple times when the filter size is small, and avoids some vortex centers being ignored when the filter size is large.

[0014] The maximum value filter and the minimum value filter traverse each pixel of the planar vortex flow field. The maximum value filter finds a local maximum of the vortex value in the pixel matrix and assigns the local maximum to the center element of the pixel matrix (i.e., the pixel corresponding to the pixel matrix) to obtain a first vortex field. The minimum value filter finds a local minimum of the vortex value in the pixel matrix and assigns the local minimum to the center element of the pixel matrix (i.e., the pixel corresponding to the pixel matrix) to obtain a second vortex field. The original vortex field is compared with the first vortex field and the second vortex field. If the vortex value of a pixel in the original vortex field is the same as the vortex value of the first vortex field, then the vortex value of that pixel is a local maximum. If the vortex value of a pixel in the original vortex field is the same as the vortex value of the second vortex field, then the vortex value of that pixel is a local minimum.

[0015] The DBSCAN clustering algorithm parameters include the neighborhood radius (γ) and the minimum number of points (minPts) required to form a high-density region. γ is between the average equivalent radius and the average equivalent diameter of the vortex in the planar vortex flow field.

[0016] Specifically, the step of clustering and merging the preliminary markers according to the DBSCAN clustering algorithm parameters includes: the DBSCAN clustering algorithm starts calculation from any unvisited preliminary marker; if the number of other preliminary markers in the γ-neighborhood of the preliminary marker is ≥ minPts, then a new cluster is created, and the preliminary marker is identified as a core point; if the number of other preliminary markers in the γ-neighborhood of the preliminary marker is < minPts, then the preliminary marker is identified as a noise point; all preliminary markers are traversed; if the preliminary marker is not a noise point, then the positions and intensity values ​​of all preliminary markers in the cluster are extracted.

[0017] In this case, the DBSCAN clustering algorithm was used to cluster and merge the repeated marker points at the vortex center, which improved the accuracy of the vortex center location calibration.

[0018] This invention also provides a method for tracking the trajectory of a vortex center in a planar flow field, wherein the position of the vortex center is calibrated according to the planar flow field vortex center calibration method, and the method further includes...

[0019] Calculate the distance between each vortex center position in the current frame flow field and all vortex center positions in the previous frame flow field, and form a distance matrix;

[0020] The initial maximum tracking distance threshold is set based on the planar vortex flow field characteristics;

[0021] The maximum tracking distance threshold is adjusted based on the average movement distance of the vortex center position of the current frame flow field relative to the vortex center position of the previous frame flow field.

[0022] Based on the distance matrix, the vortex numerical sign and intensity value, and the maximum tracking distance threshold, cross-frame matching is performed on the vortex center positions of the current frame flow field and the previous frame flow field to obtain the motion trajectory matching the vortex center.

[0023] In this case, by comparing the distance and vortex magnitude sign with the intensity value of the vortex centers in the flow field of adjacent frames, and dynamically adjusting the maximum tracking distance threshold according to the average movement distance of the vortex in the current frame, the accurate matching and trajectory tracking of the vortex centers in the flow field of adjacent frames can be achieved.

[0024] The planar vortex flow field characteristics include the time interval between the current frame flow field and the previous frame flow field, and the average moving velocity of the vortex center in the planar flow field.

[0025] Specifically, the step of performing cross-frame matching of the vortex center positions in the current frame flow field and the previous frame flow field based on the distance matrix, the vortex numerical sign and intensity value, and the maximum tracking distance threshold to obtain the motion trajectory of the vortex center includes:

[0026] Among all the vortex center positions in the previous frame flow field, find the one in the distance matrix that has the smallest distance to the vortex center position in the current frame flow field; if the smallest distance is less than the maximum tracking distance threshold, and the vortex magnitude values ​​of the vortex centers in the previous frame flow field and the current frame flow field have the same sign and the vortex magnitude intensity values ​​are comparable (with a positive or negative deviation of 20%), then add the vortex center position of the current frame flow field to the motion trajectory.

[0027] Specifically, the step of performing cross-frame matching of the vortex center positions in the current frame flow field and the previous frame flow field based on the distance matrix, vortex numerical signs and intensity values, and the maximum tracking distance threshold, to obtain the motion trajectory matching the vortex center, includes:

[0028] If no matching motion trajectory is found, a new motion trajectory is created.

[0029] The present invention also provides a motion trajectory tracking system, including a vortex center motion trajectory tracking module, used to determine the motion trajectory according to the planar flow field vortex center motion trajectory tracking method.

[0030] The planar flow field vortex center calibration method, motion trajectory tracking method, and system provided by this invention fully consider the complexity of the planar vortex flow field itself. The vortex size will vary greatly in different scenarios. By adaptively adjusting and setting the filter size and DBSCAN clustering algorithm parameters, the initial marker points calculated by the filter are combined with the clustering algorithm to achieve accurate calibration of the vortex center position in different scenarios. Based on the accurate vortex center position calibration, the distance and vortex value sign and intensity of the vortex centers in adjacent frames are compared, and the maximum tracking distance threshold is dynamically adjusted according to the average motion distance of the vortex in the current frame flow field, thereby achieving accurate matching and motion trajectory tracking of the vortex centers in adjacent frames flow fields. Attached Figure Description

[0031] Figure 1 A schematic flowchart of the planar flow field vortex center calibration method according to an embodiment of the present invention is shown;

[0032] Figure 2 A schematic diagram of the maximum and minimum value filter principle of the planar flow field vortex center calibration method involved in the embodiments of the present invention is shown.

[0033] Figure 3The diagram shows the preliminary calibration effect of the planar flow field vortex center position of the planar flow field vortex center calibration method according to the embodiments of the present invention;

[0034] Figure 4 The diagram shows the clustering and merging principle and effect of the planar flow field vortex center calibration method according to the embodiments of the present invention.

[0035] Figure 5 The diagram illustrates the principle of cross-frame matching and motion trajectory tracking of the planar flow field vortex center in the planar flow field vortex center motion trajectory tracking method according to the embodiments of the present invention.

[0036] Figure 6 The diagram shows the effect of the planar flow field vortex center motion trajectory tracking method according to the embodiment of the present invention.

[0037] Figure 7 A framework diagram of a planar flow field vortex center calibration method according to an embodiment of the present invention is shown. Detailed Implementation

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same parts, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the parts or the shapes of the parts may differ from the actual figures.

[0039] like Figure 1 As shown, the present invention provides a method 100 for calibrating the center of a vortex in a planar flow field, the method comprising:

[0040] 101. Determine the sizes of the maximum and minimum value filters and the parameters of the DBSCAN clustering algorithm based on the characteristics of the planar vortex flow field;

[0041] 102. The maximum value filter is used to calculate the local maxima of the vorticity value of the planar vortex flow field, and the minimum value filter is used to calculate the local minima of the vorticity value of the planar vortex flow field.

[0042] 103. Based on the sorting of the local maxima and local minima, determine the preliminary marker points of the vortex centers of the planar vortex flow field;

[0043] 104. Cluster and merge the initial marked points according to the DBSCAN clustering algorithm parameters;

[0044] 105. The initial marker point with the largest intensity value in each cluster is set as the vortex center position.

[0045] In this case, the complexity of the planar vortex flow field itself is fully considered. The vortex size will vary greatly in different scenarios. By adaptively adjusting and setting the filter size and DBSCAN clustering algorithm parameters, the preliminary marker points calculated by the filter are combined with the clustering algorithm to achieve accurate calibration of the vortex center position in different scenarios.

[0046] In this embodiment, both the maximum and minimum value filters comprise an M×M pixel matrix, where M represents the number of pixels the filter covers in each direction. M depends on the average size of the vortices in the planar flow field. This avoids the same vortex being marked multiple times when the filter size is small, and avoids some vortex centers being ignored when the filter size is large.

[0047] In some examples, the filter size is comparable to the minimum vortex size in the planar flow field. In this embodiment, the maximum and minimum filters traverse every pixel of the planar flow field. The maximum filter finds a local maximum of the vortex value in the pixel matrix and assigns the local maximum to the center element of the pixel matrix (i.e., the pixel corresponding to the pixel matrix) to obtain a first vortex field. The minimum filter finds a local minimum of the vortex value in the pixel matrix and assigns the local minimum to the center element of the pixel matrix (i.e., the pixel corresponding to the pixel matrix) to obtain a second vortex field. The original vortex field is compared with the first and second vortex fields. If the vortex value of a pixel in the original vortex field is the same as the vortex value of the first vortex field, then the vortex value of that pixel is a local maximum. If the vortex value of a pixel in the original vortex field is the same as the vortex value of the second vortex field, then the vortex value of that pixel is a local minimum.

[0048] like Figure 2 As shown, as an example, in this embodiment, the filter size is 5×5, and the elements of the pixel matrix represent the vorticity values ​​of the flow field regions covered by the filter. The vorticity value (13) of the center element of the pixel matrix 201 corresponding to the maximum value filter will be assigned the maximum value (39) in the neighborhood, and the vorticity value (-13) of the middle pixel of the pixel matrix 202 corresponding to the minimum value filter will be assigned the minimum value (-39) in the neighborhood.

[0049] Figure 3 The top 40 points of vorticity intensity in a planar vortex flow field are shown when using a filter of size 10×10 (301) and a filter of size 50×50 (302). Figure 3The pixel resolution of the mid-plane vortex flow field is 1024×1024. When the filter size is 10×10, multiple vortices in the planar flow field are repeatedly marked (the positions marked by the dashed circles in the figure). When the filter size is 50×50, a similar situation is avoided.

[0050] Understandably, DBSCAN is a density-based clustering algorithm that divides high-density regions into clusters and marks low-density regions as noise points.

[0051] In this embodiment, the DBSCAN clustering algorithm parameters include the neighborhood radius (γ) and the minimum number of points (minPts) required to form a high-density region, where γ is between the average equivalent radius and the average equivalent diameter of the vortex in the planar vortex flow field.

[0052] like Figure 4 As shown in (401), in this embodiment, the clustering and merging of the preliminary marked points according to the DBSCAN clustering algorithm parameters specifically includes:

[0053] The DBSCAN clustering algorithm starts its calculation from any unvisited initial marker point. If the number of other initial marker points within the γ-neighborhood of the initial marker point is greater than or equal to minPts, a new cluster is created, and the initial marker point is designated as the core point, while the other initial marker points within the γ-neighborhood are set as boundary points. If the number of other initial marker points within the γ-neighborhood of the initial marker point is less than minPts, the initial marker point is designated as a noise point. All initial marker points are traversed. If the initial marker point is not a noise point, the positions and intensity values ​​of all initial marker points in the cluster are extracted. For each cluster, the vortex center with the highest intensity is found and used as the new vortex center. By using the DBSCAN clustering algorithm to cluster and merge duplicate marker points at vortex centers, the accuracy of vortex center location calibration is improved.

[0054] like Figure 4 As shown in (402), when the neighborhood radius γ is set to 50 pixels and the minimum number of points minPts required to form a high-density region is set to 1, Figure 3 (301) shows that the repeatedly labeled vortex centers are clustered and merged into a single label. It is understandable that the two parameters of the DBSCAN clustering algorithm have a significant impact on the cluster merging effect, reducing the number of duplicate labeled points and improving the labeling accuracy.

[0055] This invention also provides a method for tracking the trajectory of a vortex center in a planar flow field. The method calibrates the position of the vortex center according to the planar flow field vortex center calibration method described above, and further includes...

[0056] Calculate the distances between the positions of all vortex centers in the current frame flow field and the positions of all vortex centers in the previous frame flow field, and form a distance matrix;

[0057] An initial maximum tracking distance threshold is set based on the planar flow field characteristics;

[0058] The maximum tracking distance threshold is adjusted based on the average movement distance of the vortex center position of the current frame flow field relative to the vortex center position of the previous frame flow field.

[0059] Based on the distance matrix, the vortex numerical sign and intensity, and the maximum tracking distance threshold, cross-frame matching is performed on the vortex center positions of the current frame flow field and the previous frame flow field to obtain the motion trajectory matching the vortex center.

[0060] In this case, by comparing the distance and vortex magnitude sign with the intensity value of the vortex centers in adjacent frames, and dynamically adjusting the maximum tracking distance threshold based on the average movement distance of the vortex in the current frame, accurate matching and trajectory tracking of the vortex centers in the flow field of adjacent frames can be achieved.

[0061] In this embodiment, the planar vortex flow field characteristics include the time interval between the current frame flow field and the previous frame flow field, and the average moving velocity of the vortex center in the planar flow field.

[0062] In this embodiment, the step of performing cross-frame matching of the vortex center positions of the current frame flow field and the previous frame flow field based on the distance matrix, vortex numerical sign and intensity value, and the maximum tracking distance threshold to obtain the motion trajectory of the vortex center specifically includes:

[0063] Among all the vortex center positions of the flow field in the previous frame, find the one with the smallest distance to the vortex center position of the current frame flow field in the distance matrix;

[0064] If the minimum distance is less than the maximum tracking distance threshold, and the vortex values ​​of the previous frame flow field and the current frame flow field have the same sign and comparable vortex intensity values, specifically, the positive or negative deviation of the vortex intensity values ​​of the previous frame flow field and the current frame flow field does not exceed 20%, then the vortex center position of the current frame flow field is added to the motion trajectory.

[0065] In some examples, the step of performing cross-frame matching of the vortex center positions of the current frame flow field and the previous frame flow field based on the distance matrix, vortex numerical sign and intensity value and the maximum tracking distance threshold, to obtain a motion trajectory matching the vortex center, specifically includes: if no matching motion trajectory is found, then a new motion trajectory is created.

[0066] In some examples, such as Figure 5 As shown, the vortex center positions of the previous frame flow field (501) and the current frame flow field (502) have shifted. By traversing all calibrated vortex center positions of the previous frame flow field, the distance between the vortex center positions of the previous frame flow field and all vortex center positions of the current frame flow field is calculated to form a distance matrix. In this embodiment, each vortex center position of the previous frame flow field (501) is traversed to find the vortex center position of the current frame flow field (502) that is closest to it in the distance matrix. If this distance is less than the maximum tracking distance threshold (δ), and the vortex magnitude values ​​of the two vortex centers have the same sign and the vortex magnitude intensity values ​​are comparable (positive or negative deviation of 20%), then they are considered to be matched, and the vortex center position of the current frame flow field (502) is added to the corresponding motion trajectory.

[0067] In this embodiment, the maximum tracking distance threshold should be between the initial maximum tracking distance threshold and twice the average movement distance, while not exceeding three times the initial maximum tracking distance threshold.

[0068] Figure 6 The trajectories of the vortex centers with the top 20 vortex intensities are displayed. Specific parameter settings are as follows: the resolution of the planar vortex flow field is 1024×1024, the maximum and minimum value filter size is 50×50, the neighborhood radius γ of the DBSCAN clustering algorithm is 50 pixels, the minimum number of points (minPts) required to form a high-density region is 1, and the initial maximum tracking distance threshold (δ) is 50 pixels. In this embodiment, 40 frames of planar vortex flow field were selected for processing, and only the trajectories of vortex centers with more than 10 frames are displayed. In practical applications, usually only vortices with high vortex intensities are considered, as these vortices have a longer lifespan in the flow field. This embodiment accurately derives the vortex trajectories in the planar flow field, demonstrating the excellent performance of the planar flow field vortex center trajectory tracking method provided by this invention.

[0069] like Figure 7 As shown, the present invention also provides a motion trajectory tracking system 700.

[0070] In some examples, the system includes a data preprocessing module 701 for preprocessing the raw planar vortex flow field data, including steps such as super-resolution reconstruction of the low-resolution vortex flow field, data cleaning, and standardization, to enhance data quality and eliminate noise and outliers.

[0071] In some examples, the system further includes a vortex center location calibration module 702, which calibrates the vortex center location according to the planar flow field vortex center calibration method described above.

[0072] In some examples, the system further includes a vortex center motion trajectory tracking module 703, used to determine the motion trajectory according to the planar flow field vortex center motion trajectory tracking method.

[0073] The embodiments described above do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the above embodiments should be included within the scope of protection of this technical solution.

Claims

1. A method for calibrating the center of a vortex in a planar flow field, characterized in that, The sizes of the maximum and minimum filters, as well as the parameters of the DBSCAN clustering algorithm, are determined based on the characteristics of the planar vortex flow field. The maximum value filter is used to calculate the local maxima of the vorticity value of the planar vortex flow field, and the minimum value filter is used to calculate the local minima of the vorticity value of the planar vortex flow field. Based on the sorting of the local maxima and local minima, preliminary marker points for the vortex centers of the planar vortex flow field are determined; The initial labeled points are clustered and merged according to the DBSCAN clustering algorithm parameters; The initial marker point with the highest intensity value in each cluster is set as the vortex center position.

2. The planar flow field vortex center calibration method as described in claim 1, characterized in that, Both the maximum value filter and the minimum value filter include an M×M pixel matrix, where M represents that the filter covers M pixels in each direction, and M depends on the average size of the vortex in the planar vortex flow field.

3. The planar flow field vortex center calibration method as described in claim 2, characterized in that, The maximum value filter and the minimum value filter traverse each pixel of the planar vortex flow field. The maximum value filter finds a local maximum of the vortex value in the pixel matrix and assigns the local maximum to the corresponding pixel to obtain a first vortex field, where the corresponding pixel is the center element of the pixel matrix. The minimum value filter finds a local minimum of the vortex value in the pixel matrix and assigns the local minimum to the center element of the pixel matrix to obtain a second vortex field. If the vortex value of a pixel in the original vortex field is the same as the vortex value of the first vortex field, then the vortex value of that pixel is the local maximum. If the vortex value of a pixel in the original vortex field is the same as the vortex value of the second vortex field, then the vortex value of that pixel is the local minimum.

4. The method for calibrating the vortex center in a planar flow field as described in claim 1, characterized in that, The DBSCAN clustering algorithm parameters include the neighborhood radius γ and the minimum number of points minPts required to form a high-density region. γ is between the average equivalent radius and the average equivalent diameter of the vortex in the planar vortex flow field.

5. The method for calibrating the vortex center in a planar flow field as described in claim 4, characterized in that, The specific steps of clustering and merging the preliminary marker points according to the DBSCAN clustering algorithm parameters include: the DBSCAN clustering algorithm starts calculation from any unvisited preliminary marker point; if the number of other preliminary marker points within the neighborhood radius of the preliminary marker point is ≥ minPts, then a new cluster is created, and the preliminary marker point is identified as a core point; if the number of other preliminary marker points within the neighborhood radius of the preliminary marker point is < minPts, then the preliminary marker point is identified as a noise point; all preliminary marker points are traversed; if the preliminary marker point is not a noise point, then the positions and intensity values ​​of all preliminary marker points in the cluster are extracted.

6. A method for tracking the trajectory of the center of a vortex in a planar flow field, characterized in that, The method for calibrating the vortex center position in a planar flow field according to any one of claims 1-5 further includes, Calculate the distances between the positions of all vortex centers in the current frame flow field and the positions of all vortex centers in the previous frame flow field, and form a distance matrix; The initial maximum tracking distance threshold is set based on the planar vortex flow field characteristics; The maximum tracking distance threshold is adjusted based on the average movement distance of the vortex center position of the current frame flow field relative to the vortex center position of the previous frame flow field. Based on the distance matrix, vorticity numerical symbol, vorticity intensity value, and the maximum tracking distance threshold, cross-frame matching is performed on the vortex center positions of the current frame flow field and the previous frame flow field to obtain the motion trajectory matching the vortex center.

7. The method for tracking the motion trajectory of the vortex center in a planar flow field as described in claim 6, characterized in that, The planar flow field characteristics include the time interval between the current frame flow field and the previous frame flow field, and the average moving velocity of the vortex center in the planar flow field.

8. The method for tracking the motion trajectory of the vortex center in a planar flow field as described in claim 6, characterized in that, The step of performing cross-frame matching of the vortex center positions in the current frame flow field and the previous frame flow field based on the distance matrix, vortex numerical sign, vortex intensity value, and the maximum tracking distance threshold to obtain the motion trajectory of the vortex center specifically includes: Among all the vortex center positions in the previous frame flow field, find the minimum distance in the distance matrix that is the smallest distance to the vortex center position in the current frame flow field; If the minimum distance is less than the maximum tracking distance threshold, and the vortex values ​​of the previous frame flow field and the current frame flow field have the same sign and the vortex intensity values ​​are equivalent, then the vortex center position of the current frame flow field is added to the motion trajectory.

9. The method for tracking the motion trajectory of the vortex center in a planar flow field as described in claim 6, characterized in that, The step of performing cross-frame matching of the vortex center positions of the current frame flow field and the previous frame flow field based on the distance matrix, vortex numerical sign, vortex intensity value, and the maximum tracking distance threshold, to obtain the motion trajectory matching the vortex center, specifically includes: If no matching motion trajectory is found, a new motion trajectory is created.

10. A motion trajectory tracking system, characterized in that, It includes a vortex center motion trajectory tracking module, used to determine the motion trajectory according to the planar flow field vortex center motion trajectory tracking method according to any one of claims 6-9.

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