Image processing-based isolation section shock train dynamic tracking and positioning method and system

Abstract

The present invention discloses a method and system for dynamic tracking and positioning of an isolation section shock train based on image processing, belonging to the technical field of dynamic monitoring of shock trains. The method comprises: obtaining the airflow direction and airflow density of the shock train of the ramjet isolation section, and constructing a density gradient square function; extracting a shock train flow field image of the density gradient square function at preset time intervals, preprocessing and edge detecting the shock train flow field image, and obtaining a shock wave pixel position image; calculating the shock wave reflection point flow direction position and the shock wave foot flow direction position of the shock train based on the shock wave pixel position image; and performing coordinate conversion on the shock wave reflection point flow direction position and the shock wave foot flow direction position based on the geometric length of the ramjet isolation section to obtain a two-dimensional spatial tracking and positioning result of the shock train. The present invention reduces irrelevant background interference in the shock train flow field by constructing a density gradient square function, improves the quality of the shock train flow field image, and realizes rapid and accurate positioning of the shock train.

Description

Technical Field

[0001] The present invention belongs to the technical field of dynamic monitoring of shock trains in the isolation section of a ramjet engine, and in particular relates to a method and system for dynamic tracking and positioning of shock trains in the isolation section based on image processing. Background Art

[0002] The isolation section is located between the ramjet engine's inlet and combustion chamber. It compresses the airflow through a shock train structure to match the combustion chamber inlet conditions, effectively preventing the combustion backpressure from interfering with the inlet operation. It is one of the key components of the ramjet engine. A shock train is a special flow phenomenon that occurs in supersonic reverse-pressure duct flow, formed by the interference of shock waves and the boundary layer. The position of the shock train's leading edge is particularly important for the stable operation of the ramjet engine. In particular, when the shock train length is too long, the first shock wave at the leading edge of the shock train will enter the inlet, causing the inlet to fail to start and deteriorating the ramjet engine's performance. Furthermore, shock trains are often unstable, typically exhibiting low-frequency self-oscillations and forced oscillations caused by unstable combustion backpressure. Oscillating shock trains can lead to serious problems such as engine performance fluctuations, wall structure resonance damage, thermal protection, and noise.

[0003] In ramjet research, precise monitoring and display technology is a crucial tool for both scientific research on shock trains and applications in isolation section engineering. Currently, preliminary detection of the shock train leading edge is primarily based on single-sided wall pressure information. This approach, however, offers limited structural analysis of the shock train, providing only a single-sided shock foot position, making it difficult to quantitatively analyze shock train structures. Furthermore, existing technologies are severely limited in their ability to monitor dynamic shock trains, making it difficult to accurately determine the real-time positions of key shock wave units within the shock train. This significantly limits research into shock train structural characteristics, oscillation suppression, and feedback control.

[0004] Therefore, improving the dynamic tracking and positioning capability of the isolation section shock wave train is particularly important for achieving efficient and stable operation of the ramjet engine. Summary of the Invention

[0005] In view of this, the present invention proposes a method and system for dynamic tracking and positioning of an isolated shock wave train based on image processing, which is used to solve the problem that the existing technology is difficult to accurately track the position of important shock wave units in the shock wave train.

[0006] In a first aspect, the present invention discloses a method for dynamic tracking and positioning of an isolation segment shock train based on image processing, the method comprising:

[0007] Obtain the airflow direction and density of the shock wave train in the ramjet isolation section, and construct a density gradient square function based on the airflow direction and density;

[0008] Extracting the shock wave train flow field image of the density gradient square function at preset time intervals, preprocessing and edge detection of the shock wave train flow field image, and obtaining the shock wave pixel position image;

[0009] Calculate the shock wave reflection point flow direction position and shock wave foot flow direction position of the shock wave train based on the shock wave pixel position image;

[0010] According to the geometric length of the ramjet isolation section, the coordinates of the shock wave reflection point and the shock wave foot in the shock wave train flow field image are converted to obtain the dynamic tracking and positioning results of the shock wave train.

[0011] On the basis of the above technical solution, preferably, the formula of the density gradient square function is:

[0012]

[0013] Where Y is the square of the density gradient, x is the direction of airflow, y is the direction perpendicular to the airflow, and ρ is the airflow density.

[0014] Based on the above technical solution, preferably, extracting the shock wave train flow field image of the density gradient square function at a preset time interval, preprocessing and edge detection of the shock wave train flow field image, and obtaining the shock wave pixel position image specifically includes:

[0015] Adjusting the display range of the density gradient square function to a first display range, wherein the shock wave train flow field image includes the positions of the first shock wave and the second shock wave;

[0016] Extracting shock wave train flow field images of density gradient square function at preset time intervals;

[0017] The shock wave train flow field image is converted into a grayscale image, and the edge of the grayscale image is extracted using an edge detection algorithm to obtain the shock wave pixel position image.

[0018] On the basis of the above technical solution, preferably, the step of calculating the flow direction position of the shock wave reflection point and the flow direction position of the shock wave foot of the shock wave train according to the shock wave pixel position image specifically includes:

[0019] Extract the minimum column index of pixels corresponding to each row of the shock wave pixel position image to form a first pixel set Φ1;

[0020] Extract the maximum value in the first pixel set Φ1, and use the pixel position corresponding to the maximum value as the flow direction position P of the reflection point of the first shock wave of the shock wave train. X1 ;

[0021] The reflection point P of the first shock wave X1The corresponding row coordinate is the row dividing point, and the minimum column index on both sides of the row dividing point is calculated as the shock foot flow direction position of the first shock wave in the shock wave train.

[0022] On the basis of the above technical solution, preferably, the reflection point P of the first shock wave X1 The corresponding row coordinates are the row dividing points. The minimum values ​​of the column indices on both sides of the row dividing points are calculated as the shock foot flow direction position of the first shock wave in the shock wave train. Specifically,

[0023] Extract the elements whose row number is less than the row dividing point in the first pixel set Φ1, calculate the minimum value of the column index among the elements whose row number is less than the row dividing point, and use the minimum value of the column index as the first shock wave foot flow direction position P of the first shock wave of the shock wave train X2 ;

[0024] Extract the elements whose row number is greater than or equal to the row dividing point in the first pixel set Φ1, calculate the minimum value of the column index among the elements whose row number is greater than or equal to the row dividing point, and use the minimum value of the column index as the flow direction position P of the second shock foot of the first shock wave of the shock wave train. X3 .

[0025] On the basis of the above technical solution, preferably, the method further comprises:

[0026] Increase the display range of the density gradient square function to the second display range so that only the right half of the first shock wave and the normal shock wave of the second shock wave are displayed on the shock wave train flow field image;

[0027] Performing edge detection on the grayscale image of the shock wave train flow field image in the second display range to obtain a new shock wave pixel position image;

[0028] Extract the maximum column index of pixels corresponding to each row of the new shock wave pixel position image to form a second pixel set Φ2;

[0029] Eliminate the elements of the first shock wave from the second pixel set Φ2 to obtain the third pixel set Φ3;

[0030] Extract the minimum value in the third pixel set Φ3, and use the pixel position corresponding to the minimum value as the flow direction position P of the reflection point of the second shock wave of the shock wave train. X4 ;

[0031] The flow direction position P of the reflection point of the second shock wave X4 The corresponding row coordinate is the row dividing point, and the maximum column index on both sides of the row dividing point is calculated as the shock foot flow direction position P of the second shock wave in the shock wave train. X5 、P X6 .

[0032] On the basis of the above technical solution, preferably, the step of removing the elements of the first shock wave from the second pixel set Φ2 to obtain the third pixel set Φ3 specifically includes:

[0033] Calculate the maximum value P in the second pixel set Φ2 max and the minimum value P min ;

[0034] Remove the elements in the second pixel set Φ2 whose values ​​are less than w×P max +(1-w)×P min The remaining elements are grouped into a third pixel set Φ3, where w∈[0,1] is a preset weight.

[0035] On the basis of the above technical solution, preferably, the formula for converting the coordinates of the shock wave reflection point flow direction position and the shock wave foot flow direction position in the shock wave train flow field image according to the geometric length of the ramjet isolation section is:

[0036]

[0037] Where i = 1, 2, 3, 4, 5, 6, L is the geometric length of the ramjet isolation section, P0 and P1 are the starting and ending positions of the column pixels of the shock wave flow field image, respectively, and P Xi is the reflection point of the shock wave or the flow direction position of the shock wave foot in the shock wave train flow field image, X i This is the tracking and positioning result of the shock wave train in two-dimensional space.

[0038] In a second aspect, the present invention discloses a system for dynamically tracking and positioning isolated shock trains based on image processing, the system comprising:

[0039] Data acquisition module: used to obtain the airflow direction and airflow density of the shock wave train in the ramjet isolation section, construct a density gradient square function based on the airflow direction and airflow density; extract the shock wave train flow field image of the density gradient square function at preset time intervals, pre-process and perform edge detection on the shock wave train flow field image to obtain the shock wave pixel position image;

[0040] Position calculation module: used to calculate the flow direction position of the shock wave reflection point and the flow direction position of the shock wave foot of the shock wave train based on the shock wave pixel position image;

[0041] Coordinate conversion module: It is used to convert the coordinates of the shock wave reflection point flow direction position and the shock wave foot flow direction position in the shock wave train flow field image according to the geometric length of the ramjet engine isolation section, and obtain the dynamic tracking and positioning results of the shock wave train.

[0042] A third aspect of the present invention discloses an electronic device, comprising: at least one processor, at least one memory, a communication interface, and a bus;

[0043] The processor, memory, and communication interface communicate with each other via the bus.

[0044] The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to implement the method according to the first aspect of the present invention.

[0045] The present invention has the following beneficial effects compared to the prior art:

[0046] 1) The present invention creates a density gradient square function based on the airflow direction and airflow density of the shock wave train in the isolation section of the ramjet engine, presenting the shock wave train flow field as a picture containing only shock waves and a monochrome background. The shock wave pixel position image obtained based on the density gradient function can eliminate all features other than the shock wave, and at the same time eliminate the influence of the wall boundary layer and reduce interference, making the shock wave train flow field clearer and easier to observe, improving the quality of the shock wave train flow field image, and providing more accurate and reliable data for dynamic tracking and positioning of the shock train.

[0047] 2) The present invention adopts an edge detection algorithm to mark the shock wave pixel position, extracts the minimum column index of the pixel corresponding to each row of the shock wave pixel position image to form a first pixel set, reflects the overall shape of the left half of the first shock wave with a smaller amount of data, reduces the difficulty of shock wave feature extraction, and obtains the flow position of the reflection point of the first shock wave of the shock wave train by extracting the maximum value in the first pixel set. The row coordinate corresponding to the reflection point of the first shock wave is used as the row dividing point, and the minimum column index values ​​on the upper and lower sides of the row dividing point are calculated as the flow position of the shock wave foot of the first shock wave of the shock wave train, thereby realizing rapid and accurate positioning of the shock wave train.

[0048] 3) The present invention can enhance the resolution of shock wave features by increasing the display range of the density gradient square function to filter out low-intensity shock waves and highlight the characteristics of high-intensity shock waves. On this basis, it further filters out the interference of the first shock wave, optimizes the shock wave feature extraction and reduces the influence of irrelevant information, and finally realizes the capture of the main position of the second curve positive shock wave in the shock wave train, thereby effectively tracking and locating the two-dimensional spatial positions of the first two shock waves in the shock wave train, thereby improving the accuracy of positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1This is a flow chart of the method for dynamic tracking and positioning of isolated shock trains based on image processing of the present invention;

[0051] Figure 2 Schematic diagram of shock wave flow field cloud diagram in the first display range Y (0-300000) of the present invention;

[0052] Figure 3 Schematic diagram of shock wave pixel position image in the first display range Y (0-300000) of the present invention;

[0053] Figure 4 Schematic diagram of shock wave pixel position image in the second display range Y (0-500000) of the present invention;

[0054] Figure 5 This is a schematic diagram of the positioning result of the main position of the second shock wave in the shock wave train according to the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0056] See also Figure 1 The present invention discloses a method for dynamic tracking and positioning of an isolation segment shock wave train based on image processing, the method comprising:

[0057] S1. Obtain the airflow direction and airflow density of the shock wave train in the ramjet isolation section, and construct a density gradient square function based on the airflow direction and airflow density.

[0058] The formula of the density gradient square function constructed by the present invention is:

[0059]

[0060] Where Y is the square of the density gradient, x is the direction of airflow, y is the direction perpendicular to the airflow, and ρ is the airflow density.

[0061] Density gradient is an important feature of airflow in a flow field. The present invention obtains the shock wave train flow field image by constructing a density gradient square function. The purpose of not squaring the density gradient in the y direction is to eliminate the influence of the wall boundary layer. This density gradient scoring function can eliminate all features except the shock wave and present the shock wave train flow field as a picture containing only the shock wave and a monochrome background.

[0062] S2. Extracting the shock wave train flow field image of the density gradient square function at preset time intervals, preprocessing and edge detection are performed on the shock wave train flow field image to obtain a shock wave pixel position image.

[0063] Adjust the display range of the density gradient square function to the first display range. In the first display range, the shock wave train flow field image includes the positions of the first shock wave and the second shock wave, and extract the shock wave train flow field image of the density gradient square function at a preset time interval. Figure 2 The figure shows a schematic diagram of the shock train flow field cloud diagram in the first display range Y (0 to 300000). Schematic diagrams X1 to X6 represent the specific positions of the first two shock waves in the shock train, indicating: the reflection position X1 of the first X / λ shock wave in the shock train; the upper shock foot position X2 of the first X / λ shock wave; the lower shock foot position X3 of the first X / λ shock wave; the position X4 of the second normal shock wave; the upper shock foot position X5 of the second normal shock wave; and the lower shock foot position X6 of the second normal shock wave.

[0064] The shock wave train flow field image is converted into a grayscale image. An edge detection algorithm is used to extract the edges of the grayscale image and mark the shock wave pixel positions to obtain a shock wave pixel position image. Specifically, shock wave detection and position marking can be achieved based on the local gradient amplitude of each pixel and a given threshold.

[0065] The present invention constructs a density gradient square function to obtain a shock wave pixel position image, eliminating all features other than the shock wave. This presents the shock wave train flow field as an image containing only the shock wave and a monochrome background, reducing interference. Simultaneously, through edge detection, all shock wave positions are represented as a data set consisting of a small number of pixel coordinates. This simplifies the entire shock wave train flow field data and significantly reduces the amount of data to be processed. S3. Calculate the shock wave reflection point flow direction position and shock wave foot flow direction position of the shock wave train based on the shock wave pixel position image.

[0066] The present invention can realize the positioning of the first two shock waves of the shock wave train. Step S3 specifically includes the following sub-steps:

[0067] S31, first shock wave positioning.

[0068] like Figure 3 The figure shows a schematic diagram of shock wave pixel position image in the first display range Y (0-300000). The present invention processes each row of pixels, first tracking the cross reflection point in the middle of the shock wave, and then capturing the upper and lower shock wave feet based on this.

[0069] S311, extract the minimum column index of the pixels corresponding to each row of the shock wave pixel position image to form a first pixel set Φ1. The first pixel set Φ1 can reflect the overall shape of the left half of the first shock wave with a relatively small amount of data, such as Figure 2 The first shock wave is shown in the middle.

[0070] S312, extract the maximum value in the first pixel set Φ1, and use the pixel position corresponding to the maximum value as the flow direction position P of the reflection point of the first shock wave of the shock wave train X1 .

[0071] That is, the maximum flow position pixel P in the first pixel set Φ1 X1 That is, the flow direction position of the middle cross reflection point of the first X / λ shock wave in the shock wave train, combined with the corresponding pixel row coordinate P Y1 The pixel coordinates of the point can be obtained.

[0072] S313, the reflection point P of the first shock wave X1 The corresponding row coordinate is the row dividing point, and the minimum column index on both sides of the row dividing point is calculated as the shock foot flow direction position of the first shock wave in the shock wave train.

[0073] Specifically, when calculating the shock foot flow direction position of the first shock wave, extract the elements with a row number less than the row dividing point in the first pixel set Φ1, calculate the minimum value of the column index among the elements with a row number less than the row dividing point, and use the minimum value of the column index as the first shock foot flow direction position P of the first shock wave of the shock wave train. X2 Extract the elements whose row number is greater than or equal to the row dividing point in the first pixel set Φ1, calculate the minimum value of the column index among the elements whose row number is greater than or equal to the row dividing point, and use the minimum value of the column index as the second shock foot flow direction position P of the first shock wave of the shock wave train X3 .

[0074] S21, positioning of the second shock wave.

[0075] On the basis of the first display range Y (0-300000), the display range of the density gradient square function is increased to the second display range Y (0-500000), thereby filtering out low-intensity shock waves, highlighting the characteristics of high-intensity shock waves, and enhancing the resolution of shock wave characteristics, so that only the right half of the first shock wave and the positive shock wave of the second shock wave are displayed on the shock wave train flow field image.

[0076] S211 , performing edge detection on the grayscale image of the shock wave train flow field image in the second display range to obtain a new shock wave pixel position image.

[0077] like Figure 4 FIG. 1 is a schematic diagram of a shock wave pixel position image in a second display range Y (0 to 500,000).

[0078] S212 , extracting the maximum column index of pixels corresponding to each row of the new shock wave pixel position image to form a second pixel set Φ2.

[0079] S213 , removing the elements of the first shock wave from the second pixel set Φ2 to obtain a third pixel set Φ3 .

[0080] Specifically, Figure 4 As shown, calculate the maximum value P in the second pixel set Φ2 max and the minimum value P min ; Remove the element value in the second pixel set Φ2 that is less than w×P max +(1-w)×P min The remaining elements are combined into a third pixel set Φ3, where w∈[0,1] is a preset weight, which can be 0.6 in this embodiment.

[0081] By removing the elements of the first shock wave, the interference of the first shock wave can be eliminated, thereby optimizing the shock wave feature extraction and reducing the influence of irrelevant information.

[0082] S214, extract the minimum value in the third pixel set Φ3, and use the pixel position corresponding to the minimum value as the flow direction position P of the reflection point of the second shock wave of the shock wave train X4 .

[0083] S215, the flow direction position P of the reflection point of the second shock wave X4 The corresponding row coordinate is the row dividing point, and the maximum column index on both sides of the row dividing point is calculated as the shock foot flow direction position P of the second shock wave in the shock wave train. X5 、P X6 .

[0084] That is, the row coordinate P of the reflection point Y4 The row dividing point, the column index of the maximum marked pixel on the upper and lower sides is the flow position P of the second shock wave foot X5 、P X6 , combined with the pixel row coordinates of the corresponding point, the pixel coordinates can be obtained, such as Figure 5 As shown, the main position of the positive shock wave of the second curve in the shock wave train is captured.

[0085] S4. Based on the geometric length of the ramjet isolation section, coordinate conversion is performed on the flow direction position of the shock wave reflection point and the flow direction position of the shock wave foot in the shock wave train flow field image to obtain the two-dimensional spatial tracking and positioning result of the shock wave train.

[0086] According to the pixel value range (P0~P1) of the flow field image of the complete isolation section shock wave train and the geometric length L of the isolation section, the tracked pixel value column index is converted into coordinates, and the flow direction position of the first two shock waves of the shock wave train at any moment can be obtained. The corresponding row coordinate is the longitudinal position, thereby effectively tracking and locating the two-dimensional spatial position of the first two shock waves of the shock wave train.

[0087] The formula for coordinate conversion is:

[0088]

[0089] Where i = 1, 2, 3, 4, 5, 6, L is the geometric length of the ramjet isolation section, P0 and P1 are the starting and ending positions of the column pixels of the shock wave flow field image, respectively, and P Xi is the reflection point of the shock wave or the flow direction position of the shock wave foot in the shock wave train flow field image, X i This is the tracking and positioning result of the shock wave train in two-dimensional space.

[0090] Assume that the maximum pixel column index range in the flow direction is 0 to 1000, the pixel row index range in the vertical direction is 0 to 200, the isolation segment length is 0.3 meters, the vertical width is 0.03 meters, the shock wave flow direction position corresponding to the 500 pixel column index is 0.15 meters, and the shock wave longitudinal position corresponding to the 100 pixel column index is 0.015 meters.

[0091] Based on the above method embodiments, the present invention further proposes an isolation segment shock train dynamic tracking and positioning system based on image processing, the system comprising:

[0092] Data acquisition module: used to obtain the airflow direction and airflow density of the shock wave train in the ramjet isolation section, construct a density gradient square function based on the airflow direction and airflow density; extract the shock wave train flow field image of the density gradient square function at preset time intervals, pre-process and perform edge detection on the shock wave train flow field image to obtain the shock wave pixel position image;

[0093] Position calculation module: used to calculate the flow direction position of the shock wave reflection point and the flow direction position of the shock wave foot of the shock wave train based on the shock wave pixel position image;

[0094] Coordinate conversion module: It is used to convert the coordinates of the shock wave reflection point flow direction position and the shock wave foot flow direction position in the shock wave train flow field image according to the geometric length of the ramjet engine isolation section, and obtain the dynamic tracking and positioning results of the shock wave train.

[0095] The above system embodiments and method embodiments correspond one to one. For a brief description of the system embodiments, please refer to the method embodiments.

[0096] The present invention also discloses an electronic device, comprising: at least one processor, at least one memory, a communication interface and a bus; wherein the processor, memory and communication interface communicate with each other through the bus; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to implement the aforementioned method of the present invention.

[0097] The present invention also discloses a computer-readable storage medium storing computer instructions that cause the computer to implement all or part of the steps of the method described in the embodiments of the present invention. The storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0098] The system embodiment described above is merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be distributed across multiple network units. A person skilled in the art may, without inventive effort, select some or all of the modules as needed to achieve the objectives of this embodiment.

[0099] The above description is only a preferred 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 method for dynamic tracking and positioning of isolated shock wave train based on image processing, characterized in that: The method comprises: Obtain the airflow direction and density of the shock wave train in the ramjet isolation section, and construct a density gradient square function based on the airflow direction and density; Extracting the shock wave train flow field image of the density gradient square function at preset time intervals, preprocessing and edge detection of the shock wave train flow field image, and obtaining the shock wave pixel position image; The steps of extracting the shock wave train flow field image of the density gradient square function at a preset time interval, performing preprocessing and edge detection on the shock wave train flow field image, and obtaining the shock wave pixel position image specifically include: Adjusting the display range of the density gradient square function to a first display range, wherein the shock wave train flow field image includes the positions of the first shock wave and the second shock wave; Extracting shock wave train flow field images of density gradient square function at preset time intervals; The shock wave train flow field image is converted into a grayscale image, and the edge of the grayscale image is extracted using an edge detection algorithm to obtain a shock wave pixel position image; Calculate the shock wave reflection point flow direction position and shock wave foot flow direction position of the shock wave train based on the shock wave pixel position image; Calculating the shock wave reflection point flow direction position and the shock wave foot flow direction position of the shock wave train according to the shock wave pixel position image specifically includes: Extract the minimum column index of the pixels corresponding to each row of the shock wave pixel position image to form the first pixel set Φ 1; Extract the first pixel set Φ 1, and the pixel position corresponding to the maximum value is taken as the flow direction position of the reflection point of the first shock wave of the shock wave train. P X1 ; The reflection point of the first shock wave P X1 The corresponding row coordinate is the row dividing point, and the minimum column index on both sides of the row dividing point is calculated as the shock foot flow direction position of the first shock wave of the shock wave train; The method further comprises: Increase the display range of the density gradient square function to the second display range so that only the right half of the first shock wave and the normal shock wave of the second shock wave are displayed on the shock wave train flow field image; Performing edge detection on the grayscale image of the shock wave train flow field image in the second display range to obtain a new shock wave pixel position image; Extract the maximum column index of each row of the new shock wave pixel position image to form the second pixel set Φ 2; From the second pixel set Φ 2. Eliminate the elements of the first shock wave and obtain the third pixel set Φ 3; Extract the third pixel set Φ 3, and the pixel position corresponding to the minimum value is used as the flow direction position of the reflection point of the second shock wave in the shock wave train. P X4 ; The flow direction position of the reflection point of the second shock wave P X4 The corresponding row coordinate is the row dividing point, and the maximum column index on both sides of the row dividing point is calculated as the shock foot flow direction position of the second shock wave in the shock wave train. P X5 、 P X6 ; According to the geometric length of the ramjet isolation section, the coordinates of the shock wave reflection point and the shock wave foot in the shock wave train flow field image are converted to obtain the dynamic tracking and positioning results of the shock wave train.

2. The method for dynamic tracking and positioning of isolated shock wave train based on image processing according to claim 1, characterized in that: The formula of the density gradient square function is: ； Where Y is the square of the density gradient, x is the airflow direction, y is perpendicular to the direction of air flow, ρ is the air flow density.

3. The method for dynamic tracking and positioning of isolated shock wave train based on image processing according to claim 1, characterized in that: The reflection point of the first shock wave P X1 The corresponding row coordinates are the row dividing points. The minimum values ​​of the column indices on both sides of the row dividing points are calculated as the shock foot flow direction position of the first shock wave in the shock wave train. Specifically, In the first pixel set Φ 1 Extract the elements whose row number is less than the row dividing point, calculate the minimum value of the column index among the elements whose row number is less than the row dividing point, and use the minimum value of the column index as the flow direction position of the first shock wave of the first shock wave train P X2 ; In the first pixel set Φ 1 Extract the elements whose row number is greater than or equal to the row dividing point, calculate the minimum value of the column index among the elements whose row number is greater than or equal to the row dividing point, and use the minimum value of the column index as the flow direction position of the second shock wave foot of the first shock wave of the shock wave train P X3 .

4. The method for dynamic tracking and positioning of isolated shock wave train based on image processing according to claim 1, characterized in that: The second pixel set Φ 2. Eliminate the elements of the first shock wave and obtain the third pixel set Φ 3 Specifically include: Calculate the second pixel set Φ 2 The maximum value in P max and minimum value P min ; Remove the second pixel set Φ 2 The inner element value is less than w× P max +(1-w)× P min The remaining elements form the third pixel set Φ 3, where w∈[0,1] is the preset weight.

5. The method for dynamic tracking and positioning of isolated shock wave train based on image processing according to claim 4, characterized in that: The formula for converting the coordinates of the shock wave reflection point flow direction position and the shock wave foot flow direction position in the shock wave train flow field image according to the geometric length of the ramjet isolation section is: ； in, i =1,2,3,4,5,6, L is the geometric length of the ramjet isolation section, P 0. P 1 are the starting position and the ending position of the column pixels of the shock wave flow field image, is the reflection point of the shock wave or the flow direction position of the shock wave foot in the shock wave train flow field image, This is the tracking and positioning result of the shock wave train in two-dimensional space.

6. A system for dynamic tracking and positioning of an isolated shock train based on image processing, using the method for dynamic tracking and positioning of an isolated shock train based on image processing according to any one of claims 1 to 5, characterized in that: The system comprises: Data acquisition module: used to obtain the airflow direction and airflow density of the shock wave train in the ramjet isolation section, construct a density gradient square function based on the airflow direction and airflow density; extract the shock wave train flow field image of the density gradient square function at preset time intervals, pre-process and perform edge detection on the shock wave train flow field image to obtain the shock wave pixel position image; Position calculation module: used to calculate the flow direction position of the shock wave reflection point and the flow direction position of the shock wave foot of the shock wave train based on the shock wave pixel position image; Coordinate conversion module: It is used to convert the coordinates of the shock wave reflection point flow direction position and the shock wave foot flow direction position in the shock wave train flow field image according to the geometric length of the ramjet engine isolation section, and obtain the dynamic tracking and positioning results of the shock wave train.

7. An electronic device, characterized in that: include: at least one processor, at least one memory, a communication interface, and a bus; The processor, memory, and communication interface communicate with each other via the bus. The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to implement the method according to any one of claims 1 to 5.

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