Plane flow field vortex center calibration method, motion trail tracking method and system

Abstract

The invention provides a plane flow field vortex center calibration method and a motion trail tracking method and system. Determining the sizes of a maximum filter and a minimum filter and parameters of a DBSCAN clustering algorithm according to the characteristics of the planar vortex flow field; calculating a local maximum value by adopting the maximum value filter, and calculating a local minimum value by adopting the minimum value filter; sorting is carried out according to the local maximum value and the local minimum value, and a preliminary mark point of the vortex center is calculated; according to the DBSCAN clustering algorithm parameters, clustering and merging are carried out on the preliminary mark points; and setting the initial mark point with the maximum intensity value in each cluster as a vortex center position. According to the method, the complexity of a planar vortex flow field is fully considered, the vortex sizes are greatly different in different scenes, the size of a filter and DBSCAN clustering algorithm parameters are adaptively adjusted and set, and the precise calibration of the vortex center position in different scenes is realized on the basis of a preliminary mark point calculated by the filter in combination with a clustering algorithm.

Description

Technical Field

[0001] The present invention relates to the field of image processing technology, and in particular to a planar flow field vortex center calibration method, a motion trajectory tracking method and a system. Background Art

[0002] The application background of the position calibration, cross-frame matching, and motion trajectory tracking of vortex centers in plane flow fields is to track the disturbance generation, development, evolution, and dissipation and extinction process of aircraft wake vortices in the atmosphere. Aircraft wake vortices are byproducts of aircraft lift generation and are characterized by being strong, stable, and large in spatial scale. During the cruise and approach phases of an aircraft, due to the long retention time of aircraft wake vortices, when the following aircraft enters the wake area of ​​the leading aircraft, the rolling torque induced by the strong vortex structure can cause the fuselage of the following aircraft to vibrate, sink, and change its flight state, thereby leading to flight accidents. Due to the interference generated by components such as control surfaces, flaps, spoilers, and landing gear, the two-dimensional cross-section of the aircraft wake area is a complex plane vortex flow field, which includes vortex generation caused by disturbances, interactions between vortices, and the gradual weakening and eventual extinction of the formed vortices due to the viscosity of the air. In observing and tracking the generation, evolution and disappearance of aircraft wake vortices in the atmosphere, position calibration, cross-frame matching and motion trajectory tracking of the vortex center are essential. Summary of the Invention

[0003] Due to the complexity of the plane vortex flow field itself, the vortex size will vary greatly in different scenarios, affecting the calibration accuracy of the vortex center. In addition, the vortex motion is subject to the overall flow characteristics (such as the Reynolds number and external drive), and is also affected by the surrounding vortices in the flow field. Therefore, the vortex motion trajectory has obvious randomness, making it difficult to track the motion trajectory.

[0004] The present invention has been developed in light of the above-mentioned existing situation. 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 thereof, so as to improve the calibration accuracy of the vortex center in a planar vortex flow field and accurately track the vortex motion trajectory. To achieve the above-mentioned purpose, the embodiments of the present invention provide the following technical solutions: The present invention provides a method for calibrating the vortex center of a plane flow field, the method comprising: Determine the maximum filter and minimum filter sizes and DBSCAN clustering algorithm parameters according to the characteristics of the plane vortex flow field; The maximum value filter is used to calculate the local maximum value of the vortex value of the plane vortex flow field, and the minimum value filter is used to calculate the local minimum value of the vortex value of the plane vortex flow field; Sorting the local maximum and the local minimum to determine a preliminary marking point of the vortex center of the plane vortex flow field; Clustering and merging the preliminary markers according to the DBSCAN clustering algorithm parameters; The preliminary marking point with the largest intensity value in each cluster is set as the vortex center position.

[0005] In this case, the complexity of the plane vortex flow field itself is fully taken into account. 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 based on the filter are combined with the clustering algorithm to achieve accurate calibration of the vortex center position in different scenarios.

[0006] The maximum filter and the minimum 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 vortices in the plane vortex flow field.

[0007] This avoids the situation where the same vortex is marked multiple times when the filter size is small, and avoids the situation where some vortex centers are ignored when the filter size is large.

[0008] Among them, the maximum filter and the minimum filter traverse each pixel point of the planar vortex flow field, find the local maximum value of the vorticity value in the pixel matrix through the maximum filter, and assign the local maximum value to the central element of the pixel matrix (that is, the pixel point corresponding to the pixel matrix) to obtain the first vortex field, and find the local minimum value of the vorticity value in the pixel matrix through the minimum filter, and assign the local minimum value to the central element of the pixel matrix (that is, the pixel point corresponding to the pixel matrix) to obtain the second vortex field; compare the original vortex field with the first vortex field and the second vortex field. If the vorticity value of a pixel of the original vortex field is the same as the vorticity value of the first vortex field, then the vorticity value of the pixel is the local maximum value; if the vorticity value of a pixel of the original vortex field is the same as the vorticity value of the second vortex field, then the vorticity value of the pixel is the local minimum value.

[0009] The DBSCAN clustering algorithm parameters include the neighborhood radius (γ) and the minimum number of points (minPts) required to form a high-density area, and γ is between the average equivalent radius and the average equivalent diameter of the vortex in the plane vortex flow field.

[0010] Among them, the clustering and merging of the preliminary marking points according to the DBSCAN clustering algorithm parameters specifically includes: the DBSCAN clustering algorithm starts calculation from any one of the preliminary marking points that has not been visited; if the number of other preliminary marking points in the γ-neighborhood of the preliminary marking point is ≥minPts, a new cluster is created, and the preliminary marking point is identified as a core point; if the number of other preliminary marking points in the γ-neighborhood of the preliminary marking point is < minPts, the preliminary marking point is identified as a noise point; all the preliminary marking points are traversed; if the preliminary marking point is not the noise point, the positions and intensity values ​​of all the preliminary marking points in the cluster are extracted.

[0011] In this case, the DBSCAN clustering algorithm is used to cluster and merge the repeated marking points at the vortex center, thereby improving the calibration accuracy of the vortex center position.

[0012] The present invention also provides a method for tracking the motion trajectory of a vortex center in a plane flow field, wherein the position of the vortex center is calibrated according to the vortex center calibration method in a plane flow field, and the method further comprises: Calculating the distance between the center position of each vortex in the current frame flow field and the center positions of all vortexes in the previous frame flow field to form a distance matrix; Setting an initial maximum tracking distance threshold according to the planar vortex flow field characteristics; adjusting the maximum tracking distance threshold according to an average moving distance of the vortex center position of the current frame flow field relative to the vortex center position of the previous frame flow field; According to the distance matrix, the numerical sign and intensity value of the vortex 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 a motion trajectory that matches the vortex center.

[0013] In this case, by comparing the distance and vortex numerical sign and intensity value of the vortex center in the adjacent frame flow field, and dynamically adjusting the maximum tracking distance threshold according to the average movement distance of the vortex in the current frame flow field, the accurate matching and motion trajectory tracking of the vortex center in the adjacent frame flow field can be achieved.

[0014] The plane vortex flow field characteristics include the time interval between the current frame flow field and the previous frame flow field and the average moving speed of the plane flow field vortex center.

[0015] The method of performing cross-frame matching on the vortex center positions of the current frame flow field and the previous frame flow field based on the distance matrix, the numerical sign and intensity value of the vortex, 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 one with the shortest distance from the vortex center position of the current frame flow field in the distance matrix; if the minimum distance is less than the maximum tracking distance threshold, and the vortex numerical signs of the vortex centers of the previous frame flow field and the current frame flow field are the same and the vortex intensity values ​​are comparable (positive and negative deviations of 20%), then add the vortex center position of the current frame flow field to the motion trajectory.

[0016] Among them, the cross-frame matching of the vortex center position of the current frame flow field and the previous frame flow field is performed based on the distance matrix, the vortex numerical sign and intensity value and the maximum tracking distance threshold, and the motion trajectory matching the vortex center is obtained, specifically including: If no matching motion trajectory is found, a new motion trajectory is created.

[0017] The present invention also provides a motion trajectory tracking system, comprising a vortex center motion trajectory tracking module, for determining the motion trajectory according to the planar flow field vortex center motion trajectory tracking method.

[0018] According to the planar flow field vortex center calibration method, motion trajectory tracking method and system provided by the present invention, the complexity of the planar vortex flow field itself is fully taken into account. The vortex size will vary greatly in different scenarios. By adaptively adjusting and setting the filter size and DBSCAN clustering algorithm parameters, the preliminary marking points calculated based on 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, by comparing the distance and vortex numerical sign and intensity of the vortex centers of adjacent frame flow fields, and dynamically adjusting the maximum tracking distance threshold according to the average motion distance of the vortex in the current frame flow field, accurate matching of the vortex centers of adjacent frame flow fields and motion trajectory tracking are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram showing a flow chart of a method for calibrating a vortex center in a planar flow field according to an embodiment of the present invention is shown; Figure 2 A schematic diagram showing the principle of maximum and minimum filters in a planar flow field vortex center calibration method according to an embodiment of the present invention is shown; Figure 3 A diagram showing the preliminary calibration effect of the plane flow field vortex center position of the plane flow field vortex center calibration method according to an embodiment of the present invention is shown; Figure 4 A schematic diagram and an effect diagram of cluster merging for calibrating the center position of a vortex in a plane flow field according to a method for calibrating the center of a vortex in a plane flow field according to an embodiment of the present invention are shown; Figure 5A schematic diagram showing the cross-frame matching and motion trajectory tracking principle of a planar flow field vortex center in a planar flow field vortex center motion trajectory tracking method according to an embodiment of the present invention is shown; Figure 6 A diagram showing the motion trajectory of a vortex center in a plane flow field according to a method for tracking the motion trajectory of a vortex center in a plane flow field according to an embodiment of the present invention is shown; 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 DESCRIPTION

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, identical components will be assigned identical reference numerals, and duplicate descriptions will be omitted. Furthermore, the accompanying drawings are merely schematic, and the proportions of the dimensions of the components and the shapes of the components may differ from the actual dimensions.

[0021] like Figure 1 As shown, the present invention provides a method 100 for calibrating the vortex center of a planar flow field, the method comprising: 101. Determine the maximum filter and minimum filter sizes and DBSCAN clustering algorithm parameters based on the plane vortex flow field characteristics; 102. Calculate the local maximum of the vorticity value of the plane vortex flow field by using the maximum filter, and calculate the local minimum of the vorticity value of the plane vortex flow field by using the minimum filter; 103. Sorting the local maximum and the local minimum to determine a preliminary marking point of the vortex center of the plane vortex flow field; 104. Clustering and merging the preliminary markers according to the DBSCAN clustering algorithm parameters; 105. Set the preliminary marking point with the largest intensity value in each cluster as the vortex center position.

[0022] In this case, the complexity of the plane vortex flow field itself is fully taken into account. 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 based on the filter are combined with the clustering algorithm to achieve accurate calibration of the vortex center position in different scenarios.

[0023] In this embodiment, both the maximum and minimum filters include an M×M pixel matrix, where M represents the number of pixels covered in each direction by the filter, and M is determined by the average size of vortices in the planar flow field. This prevents the same vortex from being marked multiple times when the filter size is small, and prevents some vortex centers from being overlooked when the filter size is large.

[0024] In some examples, the filter size is comparable to the minimum vortex size in the planar flow field. In this embodiment, the maximum filter and the minimum filter traverse each pixel of the planar flow field. The maximum filter finds the local maximum of the vorticity value in the pixel matrix and assigns the local maximum to the central element of the pixel matrix (i.e., the pixel corresponding to the pixel matrix) to obtain a first vorticity field. The minimum filter finds the local minimum of the vorticity value in the pixel matrix and assigns the local minimum to the central element of the pixel matrix (i.e., the pixel corresponding to the pixel matrix) to obtain a second vorticity field. The original vorticity field is compared with the first vorticity field and the second vorticity field. If the vorticity value of a pixel in the original vorticity field is the same as the vorticity value of the first vorticity field, the vorticity value of the pixel is a local maximum. If the vorticity value of a pixel in the original vorticity field is the same as the vorticity value of the second vorticity field, the vorticity value of the pixel is a local minimum.

[0025] 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 area covered by the filter. The vorticity value (13) of the center element of the pixel matrix 201 corresponding to the maximum 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 filter will be assigned the minimum value (-39) in the neighborhood.

[0026] Figure 3 The top 40 marker points of vorticity intensity in the plane vortex flow field when using a filter (301) with a size of 10×10 and a filter (302) with a size of 50×50 are shown. Figure 3 The pixel resolution of the mid-plane vortex flow field is 1024×1024. When the filter size is 10×10, multiple vortices in the plane flow field are repeatedly marked (the positions marked by the dotted circles in the figure). When the filter size is 50×50, a similar situation is avoided.

[0027] It can be understood that DBSCAN is a density-based clustering algorithm that divides high-density areas into clusters and marks low-density areas as noise points.

[0028] 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 area, and γ is between the average equivalent radius and the average equivalent diameter of the vortex in the plane vortex flow field.

[0029] like Figure 4As shown in (401), in this embodiment, clustering and merging the preliminary markers according to the DBSCAN clustering algorithm parameters specifically includes: The DBSCAN clustering algorithm starts with any of the unvisited preliminary marking points. If the number of other preliminary marking points in the γ-neighborhood of the preliminary marking point is ≥ minPts, a new cluster is created, and the preliminary marking point is identified as a core point. The other preliminary marking points in the γ-neighborhood are set as boundary points. If the number of other preliminary marking points in the γ-neighborhood of the preliminary marking point is < minPts, the preliminary marking point is identified as a noise point. All the preliminary marking points are traversed. If the preliminary marking point is not a noise point, the positions and intensity values ​​of all the preliminary marking points in the cluster are extracted. For each cluster, the vortex center with the largest intensity is found and used as the new vortex center. The repeated marking points at the vortex center are clustered and merged by the DBSCAN clustering algorithm, which improves the calibration accuracy of the vortex center position.

[0030] 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 area is set to 1, Figure 3 The vortex center clusters that were repeatedly marked as shown in (301) are merged into a single calibration. It can be understood that the two parameters of the DBSCAN clustering algorithm have a significant impact on the cluster merging effect, reducing the number of repeated marking points and improving the calibration accuracy.

[0031] The embodiment of the present invention also provides a method for tracking the motion trajectory of a vortex center in a plane flow field. The vortex center position is calibrated according to the above-mentioned vortex center calibration method in a plane flow field, and the method further includes: Calculating the distances between the center positions of all vortices in the current frame flow field and the center positions of the vortices in the previous frame flow field to form a distance matrix; Setting an initial maximum tracking distance threshold according to the plane flow field characteristics; adjusting the maximum tracking distance threshold according to an average moving distance of the vortex center position of the current frame flow field relative to the vortex center position of the previous frame flow field; According to the distance matrix, the numerical sign and intensity of the vortex 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 a motion trajectory that matches the vortex center.

[0032] In this case, by comparing the distance and vortex numerical signs and intensity values ​​of the vortex centers in adjacent frames and dynamically adjusting the maximum tracking distance threshold according to the average motion distance of the vortex in the current frame flow field, accurate matching and motion trajectory tracking of the vortex centers in adjacent frames of flow field can be achieved.

[0033] In this embodiment, the plane vortex flow field characteristics include the time interval between the current frame flow field and the previous frame flow field and the average moving speed of the plane flow field vortex center.

[0034] In this embodiment, the vortex center position of the current frame flow field and the previous frame flow field is matched across frames 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, specifically including: Among all the vortex center positions of the previous frame flow field, find the one with the smallest distance from the vortex center position of the current frame flow field in the distance matrix; If the minimum distance is less than the maximum tracking distance threshold, and the vorticity values ​​of the previous flow frame and the current flow frame have the same sign and are comparable in vorticity intensity (specifically, the positive or negative deviation between the vorticity intensity values ​​of the previous flow frame and the current flow frame does not exceed 20%), then the vortex center position of the current flow frame is added to the motion trajectory.

[0035] In some examples, the cross-frame matching of the vortex center positions of the current frame flow field and the previous frame flow field is performed based on the distance matrix, the numerical sign and intensity value of the vortex, and the maximum tracking distance threshold to obtain a motion trajectory that matches the vortex center, specifically including: if no matching motion trajectory is found, creating a new motion trajectory.

[0036] 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) are offset. By traversing all the calibrated vortex center positions of the previous frame flow field, the distance between the vortex center position of the previous frame flow field and all the 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 values ​​of the two vortex centers have the same sign and the vortex intensity values ​​are comparable (positive and negative deviations of 20%), 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.

[0037] In this embodiment, the maximum tracking distance threshold should be between the initial maximum tracking distance threshold and 2 times the average moving distance, and should not exceed 3 times the initial maximum tracking distance threshold.

[0038] Figure 6 The motion trajectories of the vortex centers with the top 20 vortex value intensities are displayed. Specific parameter settings are: the resolution of the plane vortex flow field is 1024×1024, the maximum and minimum filter sizes are 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 area is 1, and the initial maximum tracking distance threshold (δ) is 50 pixels. In this embodiment, 40 frames of plane vortex flow fields are selected for processing, and only the motion trajectories of the vortex center trajectories containing more than 10 frames are displayed. In actual application, usually only vortices with larger vortex value intensities are concerned, and such vortices also have a longer life cycle in the flow field. This embodiment accurately obtains the motion trajectory of the vortex in the plane flow field, indicating that the plane flow field vortex center motion trajectory tracking method provided by the present invention performs excellently.

[0039] like Figure 7 As shown, the present invention also provides a motion trajectory tracking system 700.

[0040] In some examples, the system includes a data preprocessing module 701 for preprocessing the original plane vortex flow field data, including super-resolution reconstruction of the low-resolution vortex flow field, data cleaning and standardization, etc., to enhance data quality and eliminate noise and outliers.

[0041] In some examples, the system further includes a vortex center position calibration module 702 for calibrating the vortex center position according to the planar flow field vortex center calibration method described above.

[0042] In some examples, the system further includes a vortex center motion trajectory tracking module 703 for determining the motion trajectory according to the planar flow field vortex center motion trajectory tracking method.

[0043] The above-described embodiments do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the above-described embodiments shall be included in the scope of protection of this technical solution.

Claims

1. A method for calibrating the vortex center of a plane flow field, characterized in that: Determine the maximum filter and minimum filter sizes, as well as the DBSCAN clustering algorithm parameters, based on the characteristics of the plane vortex flow field; The maximum value filter is used to calculate the local maximum value of the vortex value of the plane vortex flow field, and the minimum value filter is used to calculate the local minimum value of the vortex value of the plane vortex flow field; Sorting the local maximum and the local minimum to determine a preliminary marking point of the vortex center of the plane vortex flow field; Clustering and merging the preliminary markers according to the DBSCAN clustering algorithm parameters; The preliminary marking point with the largest intensity value in each cluster is set as the vortex center position.

2. The method for calibrating the vortex center of a plane flow field according to claim 1, wherein: The maximum value filter and the minimum value filter both include an M×M pixel matrix, where M indicates that the filter covers M pixels in each direction, and M depends on the average size of vortices in the planar vortex flow field.

3. The method for calibrating the vortex center of a plane flow field according to claim 2, wherein: The maximum filter and the minimum filter traverse each pixel point of the planar vortex flow field, find the local maximum value of the vortex value in the pixel matrix through the maximum filter, and assign the local maximum value to the pixel point corresponding to the pixel matrix to obtain a first vortex field, and the corresponding pixel point is the central element of the pixel matrix; the local minimum value of the vortex value in the pixel matrix is ​​found through the minimum filter, and the local minimum value is assigned to the central element of the pixel matrix to obtain a second vortex field; if the vortex value of a pixel of the original vortex field is the same as the vortex value of the first vortex field, then the vortex value of the pixel is the local maximum value; if the vortex value of a pixel of the original vortex field is the same as the vortex value of the second vortex field, then the vortex value of the pixel is the local minimum value.

4. The method for calibrating the vortex center of a plane flow field according to claim 1, wherein: The DBSCAN clustering algorithm parameters include the neighborhood radius γ and the minimum number of points minPts required to form a high-density area, where γ is between the average equivalent radius and the average equivalent diameter of the vortex in the plane vortex flow field.

5. The method for calibrating the vortex center of a plane flow field according to claim 4, wherein: The clustering and merging of the preliminary marking points according to the DBSCAN clustering algorithm parameters specifically includes: the DBSCAN clustering algorithm starts calculation from any one of the preliminary marking points that has not been visited; if the number of other preliminary marking points within the neighborhood radius of the preliminary marking point is ≥ minPts, a new cluster is created and the preliminary marking point is identified as a core point; if the number of other preliminary marking points within the neighborhood radius of the preliminary marking point is < minPts, the preliminary marking point is identified as a noise point; all the preliminary marking points are traversed; if the preliminary marking point is not a noise point, the positions and intensity values ​​of all the preliminary marking points in the cluster are extracted.

6. A method for tracking the motion trajectory of a vortex center in a plane flow field, characterized in that: The vortex center position is calibrated according to the planar flow field vortex center calibration method according to any one of claims 1 to 5, the method further comprising: Calculating the distances between the center positions of all vortices in the current frame flow field and the center positions of the vortices in the previous frame flow field to form a distance matrix; Setting an initial maximum tracking distance threshold according to the planar vortex flow field characteristics; adjusting the maximum tracking distance threshold according to an average moving distance of the vortex center position of the current frame flow field relative to the vortex center position of the previous frame flow field; According to the distance matrix, the numerical sign of the vortex, the vortex 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 a motion trajectory that matches the vortex center.

7. The method for tracking the motion trajectory of the vortex center in a plane flow field according to claim 6, characterized in that: The plane flow field characteristics include the time interval between the current frame flow field and the previous frame flow field and the average moving speed of the vortex center in the plane flow field.

8. The method for tracking the motion trajectory of the vortex center in a plane flow field according to claim 6, wherein: The method of performing cross-frame matching on the vortex center positions of the current frame flow field and the previous frame flow field according to the distance matrix, the vortex numerical sign, the 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 of the previous frame flow field, finding the minimum distance from the vortex center position of the current frame flow field in the distance matrix; If the minimum distance is less than the maximum tracking distance threshold, and the vortex numerical signs of the previous frame flow field and the current frame flow field are the same and the vortex intensity values ​​are comparable, 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 plane flow field according to claim 6, wherein: The method of performing cross-frame matching on the vortex center positions of the current frame flow field and the previous frame flow field according to the distance matrix, the vortex numerical sign, the vortex intensity value and the maximum tracking distance threshold, and obtaining a 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, which is 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 to 9.

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