Air explosion point three-dimensional coordinate detection device and measurement method

Abstract

The application discloses an air burst point three-dimensional coordinate detection device and a measuring method, which comprises a burst point image processing system and at least two high-speed cameras; at least one high-speed camera is arranged on each side of the terminal trajectory in the safe area, so that the pre-burst range of the shell is in the intersection detection field area of the high-speed cameras on both sides of the trajectory; a test marker is placed at the theoretical burst point, and the coordinates are measured; a sky screen target trigger device is placed in the safe area below the front pre-trajectory at a distance of 300-500 meters from the center of the high-speed cameras on both sides of the trajectory; the burst point image processing system and a Beidou time system device are arranged in the safe area outside the burst point; the high-speed cameras are connected with the sky screen target trigger device, the burst point image processing system and the Beidou time system device; and the Beidou time system device is connected with the burst point image processing system. The application solves the problem of the instantaneous three-dimensional coordinate measurement of the air burst point influenced by the frame frequency limitation of the high-speed camera, and improves the precision of the burst point coordinate measurement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of image processing technology and target detection, and particularly relates to an air burst point three-dimensional coordinate detection device and a measurement method. BACKGROUND

[0002] In a target range test, the measurement of the space coordinates of a burst point is one of the most important test items of a conventional target range, and is of great significance to the damage effectiveness evaluation of a weapon system. There are three common methods for the measurement of the space coordinates of a burst point: an optical-electric measurement method, an acoustic sensor measurement method and an image measurement method. The optical-electric measurement method mainly uses an optical-electric theodolite to measure the coordinates of a burst point, and has the advantages of early start, wide application and high automation. The current burst point theodolite is the main near-ground burst point measurement equipment of a target range. However, the burst point theodolite also has defects in practical application. For example, the focal length is fixed, the lens and the camera are packaged integrally and cannot be replaced, the application range is limited for different test requirements, and the traditional burst point theodolite has a low frame frequency, so that the first frame of explosion image captured is large, and the extraction accuracy of the pixel coordinates of the burst point is affected. The acoustic sensor measurement method obtains the explosion shock wave information radiated around when explosion occurs, combines a sky screen and a burst point flame detector, and measures the flight direction of a shell and the three-dimensional coordinates of a burst point by using a multi-sensor information fusion theory. The array arrangement is flexible, the detection range is wide, the distance is far, the method is not affected by the visibility and the observation field of view shielding, and the method can be used all day and all weather. However, the explosion sound wave is greatly affected by the terrain and the environment of the shell falling area, the sound wave signal is easily confused and stuck together, and the positioning error is large. The image measurement method uses a high-speed camera to track and shoot a measurement target, and has the advantages of convenient station arrangement and flexible replacement of multiple lenses. In recent years, the method has been applied more in target range tests. Because the explosion flame of a shell rapidly expands and produces smoke at the moment of explosion, the flame maintains for only a few milliseconds, and therefore the explosion has high speed and is instantaneous. The first frame of flame image information at the moment of explosion cannot be captured due to the limitation of the frame frequency of the high-speed camera. SUMMARY

[0003] The present application solves the problem of providing an air burst point three-dimensional coordinate detection device and a measurement method, and solves the problem of the measurement of instantaneous three-dimensional coordinates of an air burst point affected by the limitation of the frame frequency of a high-speed camera, and improves the accuracy of the measurement of the coordinates of a burst point.

[0004] The present application is realized by the following technical scheme:

[0005] An air burst point instantaneous three-dimensional coordinate measurement method using an air burst point instantaneous three-dimensional coordinate detection device, comprising the following steps:

[0006] Step 1): An air burst point image processing system detects and identifies the shell image information of a shell before explosion at a frame before explosion and the first frame of shell flame image information appearing after explosion, and corresponding each frame of time T n-1 , Tn1 , the frame blending interpolation algorithm in the image interpolation algorithm is adopted, and combined with the fireball expansion model of the shell explosion, each pixel point of the inserted frame image is calculated to generate the intermediate frame image Gd0(u e ,v e ,t0), that is, the first moment of the fire image information when the shell is detonated;

[0007] Step 2): analyze the intermediate frame image Gd0(u e ,v e ,t0) generated in step 1), there are two cases: 1) after the shell and the first moment of the fire image frame of the shell detonation are mixed, there is no superposition or partial superposition, then the burst point coordinates of the intermediate frame image are the middle points of the shell coordinates and the center coordinates of the first moment of the fire image when the shell is detonated; 2) after the shell and the first moment of the fire image frame of the shell detonation are mixed, the shell target is completely overlapped with the fire image, then the burst point coordinates of the intermediate frame image are the center coordinates of the first moment of the fire image when the shell is detonated;

[0008] According to the analysis result, the first moment of the fire image information of the shell detonation obtained in step 1) is calculated by the center of gravity coordinate extraction algorithm based on the rectangle to obtain the burst point coordinates (u e ,v e ,t0) of the intermediate frame image Gd0(u p0 ,v p0 ); and the frame moment of the corresponding interpolation image is calculated;

[0009] Step 3): according to the test flag image, the camera internal and external calibration parameters are solved, the system calibration data is obtained; by establishing the image pixel coordinate system, the image coordinate system, the camera coordinate system and the world coordinate system, combining the conversion relationship between each coordinate system, the space burst point coordinate model is solved, and the burst point coordinates (u e ,v e ,t0) of the intermediate frame image Gd0(u p0 ,v p0 ) obtained in step 2) are substituted into the space burst point coordinate model, and the space three-dimensional coordinates of the burst point and the explosion moment are solved.

[0010] Before step 1), the following steps are further included:

[0011] Step 4): a sky screen target trigger device, a test flag, a burst point image processing system, a Beidou time system device and at least two high-speed cameras installed on both sides of the terminal trajectory are arranged in the terminal trajectory safety area; and each device is installed to form an air burst point instantaneous three-dimensional coordinate detection device;

[0012] Step 5) When the target shell passes through the detection area of the sky screen target trigger device, the sky screen target trigger device outputs a trigger signal, and simultaneously starts the high-speed cameras on both sides of the trajectory to collect real-time continuous high-frame frequency video images of the target shell, and caches the collected images to obtain target shell sequence image information, and sends the obtained target shell sequence image information to the burst point image processing system;

[0013] Step 6) The burst point image processing system receives the target shell sequence image information sent by the high-speed camera, and extracts the image information of the burst point area by using a video frame extraction method, and then detects and identifies the shell image information before the shell explodes and the shell fire image information when the first frame of fire appears after the shell explodes by using a background reduction and morphological filtering method, and corresponds to each frame of time T n-1 、T n1 .

[0014] The step 4) is specifically:

[0015] At least one high-speed camera is erected on both sides of the trajectory at the station position of the safety area of the terminal trajectory by using a tripod, and rock protection is performed, so that the shell pre-explosion range is in the intersection detection field area of the high-speed cameras on both sides of the trajectory, the sky screen target trigger device is arranged at a safety area below the pre-trajectory at a distance of 300-500 meters from the center of the high-speed cameras on both sides of the trajectory, at least two groups of test markers are placed at the theoretical burst point, and the coordinates of the test markers are measured, the burst point image processing system and the Beidou time system device are arranged in a safety area outside the burst point, and rock protection is performed; the high-speed cameras are connected with the sky screen target trigger device, the burst point image processing system and the Beidou time system device, and the Beidou time system device is connected with the burst point image processing system;

[0016] Step 5) is specifically: when the target shell passes through the light curtain formed by the sky screen optical lens of the sky screen target trigger device, a part of light is blocked by the target shell, so that the light flux on the photosensitive surface of the photoelectric sensor on the sky screen optical lens changes, the changed light flux is processed by an analog circuit to extract, amplify, noise filter and level conversion circuit, and finally a fixed pulse width TTL level signal is output simultaneously to the high-speed cameras on both sides of the trajectory, the high-speed cameras on both sides of the trajectory are started to collect real-time continuous high-frame frequency video images of the target shell, and the collected images are cached to obtain target shell sequence image information, and the obtained target shell sequence image information is sent to the burst point image processing system;

[0017] Step 6) is specifically:

[0018] extracting the start and end time of the target shell video information before and after the target shell explosion from the target shell sequence image information obtained in step 5), and using video frame processing to derive each frame of JPEG image I(u e ,v e ,t) with time mark; obtaining the image before the shell enters the field of view as the background image M bg (u e ,v e ,t0); using the background difference algorithm to process the target shell sequence image information with time mark to extract the shell image information M n-1 (u e ,v e ,t n-1 ) before explosion and the first frame of shell fire image information M n1 (u e ,v e ,t n1 ) after explosion, wherein the background difference algorithm is:

[0019] M n-1 (u e ,v e ,t n-1 )=I(u e ,v e ,t n-1 )-M bg (u e ,v e ,t0)

[0020] M n1 (u e ,v e ,t n1 )=I(u e ,v e ,t n1 )-M bg (u e ,v e ,t0)

[0021] Then, a gray image is set in the multi-gray target shell sequence image information after background subtraction, and the gray image is M(u e ,v e ,t). A gray value T is found in the gray image M(u e ,v e ,t) as a threshold, the image is divided into two parts, then the initial multi-gray target shell sequence image information is binarized, the threshold T is determined by the maximum inter-class variance method, and all pixels of the image are mutually exclusive and divided into object pixel set G O and background pixel set G B , assuming that the two pixel sets have wO (t), w B (t) pixels, and the average gray level of each is μ O (t) and μ B (t), and the variance of the gray level distribution of each is σ O 2 (t) and σ B 2 (t), then the maximum inter-class variance method will find the threshold T * , that is:

[0022]

[0023] The pixel value greater than or equal to T is set to 1, and the pixel value less than the threshold is set to 0. The binary process can be expressed in mathematical expression as:

[0024]

[0025] Then the morphological filtering method is used to process the bomb image information Gd n-1 (u e ,v e ,t n-1 ) before explosion of the previous frame and the bomb fire image information Gd n1 (u e ,v e ,t n1 ) after explosion of the first frame of fire, and the open operation filtering processing of erosion first and then dilation is performed, small particle noise is removed, the boundary of the bomb target and the fire target is smoothed, the shape and area are not changed, the bomb target and the fire target are accurately extracted, and the bomb image information Gd n-1 (u e ,v e ,t n-1 ) before explosion of the previous frame and the bomb fire image information Gd n1 (u e ,v e ,t n1 ) after explosion of the first frame of fire are obtained.

[0026] The step 1) is specifically:

[0027] The bomb image Gd n-1 (u e ,v e ,t n-1 ) before explosion of the previous frame and the bomb fire image Gd n1 (u e ,v et n1 ) into the interpolation algorithm, and combined with the expanding model of the fireball of the shell explosion, it is assumed that the weight of the frame before initiation is L-a / L, and the weight of the first frame of fire image after initiation is a / L, and the two reference frames are added after being multiplied by their respective weights to obtain the intermediate frame image Gd0(u e ,v e ,t0); wherein the algorithm is as follows:

[0028]

[0029] wherein, L is the distance between two original frames, and a is the relative distance between the frame before initiation and the inserted frame;

[0030] The insertion frame time is:

[0031] T n0 =T n-1 +α

[0032] Step 2) is specifically:

[0033] The two position relations of the intermediate frame image obtained in step 1) are determined:

[0034] (1) The superposition or partial superposition of the shell and the fire image, then the burst point coordinates of the intermediate frame image are the middle points of the shell coordinates and the center pixel coordinates of the fire image; (2) The target of the shell is completely coincided with the fire image, then the burst point coordinates of the intermediate frame image are the center pixel coordinates of the fire image;

[0035] According to the determination result, the barycentric coordinate extraction algorithm based on the matrix is used to calculate the burst point coordinates of the intermediate frame image, assuming that the quality of each pixel in the firelight region of the burst point fire image is 1, that is, the quality of each pixel is equal to its pixel value, (u e ,v e ) is the coordinates of the image pixels, and S is the area of the pixel region, then the p+q order moment of the target can be expressed as:

[0036]

[0037] In the formula, M is the moment of the image under different p and q values, f(u e ,v e ) is the quality of a pixel; The zeroth moment and the first moment are calculated respectively, and there are three cases as follows:

[0038] When p=0, q=0, the zeroth moment M(0,0) is:

[0039]

[0040] When p=1, q=0, the first moment M(0,1) is:

[0041]

[0042] When p = 0, q = 1, the value of the first moment M(1, 0) is:

[0043]

[0044] The center of gravity of the target image can be calculated using the zeroth moment and the first moment, and the coordinates of the explosion point of the intermediate frame image are represented by (u p0 ,v p0 ), so the algorithm for solving the coordinates of the explosion point is:

[0045]

[0046] where M(1, 0) represents the sum of the horizontal coordinates of all pixels of the bullet hole, M(0, 1) represents the sum of the column coordinates of all pixels of the bullet hole, and M(0, 0) represents the number of pixels contained in the bullet hole;

[0047] Step 3) is specifically: solving the spatial explosion point coordinate model and bringing the explosion point coordinates into it to solve the spatial three-dimensional coordinates of the explosion point:

[0048] Assuming that the three-dimensional coordinates of the spatial explosion point P in the world coordinate system are (X P ,Y P ,Z P ), and the image coordinates after imaging are (u P ,v P ), the linear model of the high-speed camera can be represented as:

[0049]

[0050] The camera distortion model is as follows:

[0051]

[0052] where, Considering the second-order radial distortion, the distortion coefficients are a1 and a2; λ is the scale factor, (u w ,v w ) are the distortion-free image coordinates, (R, T) are the external parameters of the camera, R and T are the rotation matrix and translation vector from the world coordinate system to the camera coordinate system, respectively, and A is the internal parameter matrix of the camera, which can be represented as:

[0053]

[0054] In the formula, (u0, v0) are the principal point coordinates of the image coordinate system, f x , f yScale factors of u-axis and v-axis, and non-perpendicular factors of u-axis and v-axis; 5 parameters of camera internal parameter matrix to be referenced in high-speed camera calibration x , f y , a, u0 and v0, and distortion coefficients a1 and a2

[0055] Before the test, two standard test poles are rotated in multiple directions in the range of the shell pre-detonation point, and multiple standard test pole images in different directions are shot by a high-speed binocular camera; 5 parameters of camera calibration and camera distortion coefficients are calculated according to the imaging relationship of feature points on the standard test pole on the binocular camera composed of two high-speed cameras;

[0056] An image pixel coordinate system, an image coordinate system, a camera coordinate system and a world coordinate system are established; the calculation steps of conversion between the coordinate systems are as follows:

[0057] 1) Conversion relationship between the pixel coordinate system and the image coordinate system

[0058] The image pixel coordinate system takes the upper left corner of the image as the coordinate origin, takes the row and column as the u-axis and v-axis directions of the coordinate system respectively, and is a two-dimensional coordinate system in a plane, which is in units of pixels and has the image size as the image resolution; the pixel coordinates are the positions of the pixels in the image; however, the pixel cannot reflect the physical size of the object in the image, so the image coordinate system is established; the origin of the coordinate system is established at the intersection between the pixel coordinate system and the optical axis of the camera and the imaging plane of the camera photoelectric sensor, the x-axis is parallel to the u-axis of the pixel coordinate system, and the y-axis is parallel to the v-axis of the pixel coordinate system; the pixel coordinates of the image center are (u0, v0), the physical sizes of each pixel on the CCD camera target surface in the x-axis and y-axis directions are dx and dy respectively, and the relationship between the pixel coordinates (u, v) and the image coordinates (x, y) is:

[0059] x = udx - u0dx

[0060] y = vdy - v0dy

[0061] The relationship is written in the form of homogeneous coordinates as follows:

[0062]

[0063] wherein (u0, v0) are the coordinates of the image center, 1 / dx and 1 / dy are the sampling frequencies in the x and y directions respectively, i.e. the number of pixels per unit length;

[0064] 2) Conversion relationship between the camera coordinate system and the image coordinate system

[0065] The camera coordinate system is established on the camera, and the coordinate system takes the optical system projection center O cAs the coordinate origin, the Z axis is the optical axis of the camera, and the X and Y axes form a right-handed coordinate system; the relationship between the object point P(X c ,Y c ,Z c ) in the camera coordinate system and the image point p(x, y) in the image coordinate system is:

[0066] x = fX c / Z c

[0067] y = fY c / Z c

[0068] Write it as a homogeneous coordinate form:

[0069]

[0070] 3) Camera coordinate system and world coordinate system and transformation relationship

[0071] The measurement coordinate system of the control point is the object space coordinate system; the mapping of the point in the world coordinate system to the camera coordinate system is represented by an orthogonal rotation matrix R and a translation matrix T, and the formula is:

[0072]

[0073] Write it as a homogeneous coordinate form:

[0074]

[0075] Wherein, the orthogonal rotation matrix R is the cosine combination of the direction of the camera coordinate system relative to the coordinate axis of the world coordinate system, and the translation matrix T = [t1 t2 t3] T is the coordinate of the camera coordinate system origin in the world coordinate system;

[0076] Combined with the conversion relationship between various coordinate systems, the transformation relationship from the pixel coordinate system to the world coordinate system is as follows:

[0077]

[0078] Wherein, the value of Z c is 1, wherein s is the coordinate axis inclination parameter, which is 0 in the ideal case, A is the camera internal parameter matrix, R is the rotation matrix T is the translation matrix; further solving the above formula, the conversion relationship between the system pixel coordinates and the world coordinate system is:

[0079]

[0080] Let then the above formula can be simplified to the following space explosion point coordinate model:

[0081] [X Y Z 1] T =C -1 [u v 1] T (2.13)

[0082] In the formula, (X, Y, Z) is the solved spatial burst point coordinates, with units of meters; (u, v) is the pixel coordinates, with units of pixels;

[0083] Wherein, the step 2) obtained by the burst point coordinates (u p0 ,v p0 ) into the above formula space burst point coordinates model, get the burst moment burst point space three-dimensional coordinates (X, Y, Z).

[0084] An air burst point instantaneous three-dimensional coordinate detection device, comprising a sky screen trigger device, a test marker, a burst point image processing system, a Beidou timing device and at least two high-speed cameras; at least one high-speed camera is erected on both sides of the trajectory by a tripod at the station position of the safety area of the terminal trajectory, and rock protection is made, so that the pre-burst range of the shell is in the intersection detection field area of the high-speed cameras on both sides of the terminal trajectory, the sky screen trigger device is arranged below the pre-trajectory in the safety area 300-500 meters in front of the center position of the high-speed cameras on both sides of the terminal trajectory, a test marker is placed at the theoretical burst point, and the coordinates of the test marker are measured, the burst point image processing system and the Beidou timing device are arranged in the safety area outside the burst point, and rock protection is made; the high-speed cameras are connected with the sky screen trigger device, the burst point image processing system and the Beidou timing device respectively, and the Beidou timing device is connected with the burst point image processing system.

[0085] The test marker is at least two groups of test markers.

[0086] The high-speed camera is used for synchronously shooting the sequence image information of the target cannonball in the terminal trajectory from multiple angles and close distances; the screen target trigger device is used for providing uniform trigger signals to the high-speed cameras on both sides of the trajectory, so as to ensure that the high-speed cameras are provided with accurate synchronous starting shooting signals when the cannonball flies through the screen target trigger device, so that the high-speed cameras accurately shoot the image information of the period before and after the explosion of the cannonball, and the storage capacity of the image information of the high-speed camera is reduced; the test marker is used for providing known coordinate points for the high-speed cameras on both sides of the trajectory before the test starts, and calibrating the internal and external parameters of the high-speed camera and calculating the space coordinates after the test; the burst point image processing system is used for obtaining the cannonball image information before the explosion of the cannonball and the cannonball fire image information of the first frame of the fire light after the explosion of the cannonball by using the image frame division, and obtaining the fire light image information of the first time of the explosion of the cannonball by using the image frame interpolation algorithm combined with the explosion fireball inflation model, and calculating the space three-dimensional coordinates of the burst point at the first time of the explosion of the cannonball and the explosion time information by using the fire light image information of the first time of the explosion of the cannonball.

[0087] Compared with the prior art, the present application has the following beneficial technical effects:

[0088] The air burst point three-dimensional coordinate detection device and the measurement method based on the image frame interpolation method provided by the present application are based on the binocular high-speed camera detection mechanism, fully utilize the relationship between the sequence images of the camera shooting burst point formation process, generate more accurate first frame fire light image of the burst point explosion time by using the image frame interpolation method, form continuous frame images, and solve the problem that the camera frame frequency is limited and the initial time fire light image information of the explosion fireball cannot be captured, so that the air burst point coordinate calculation accuracy is improved.

[0089] The air burst point three-dimensional coordinate detection device and the measurement method based on the image frame interpolation method provided by the present application solve the technical problems in the prior art that the explosion fire light diffusion speed is very fast, the high-speed camera frame frequency is limited, the initial time image information of the explosion fireball cannot be captured, and the first frame image of the explosion fireball after the explosion is a large fireball, even an irregular fireball, which leads to a large deviation in the calculation of the instantaneous coordinates of the explosion fireball. The present application can generate coherent intermediate images, predict the fire light image information of the first time of the explosion of the explosive, calculate the space three-dimensional coordinates of the burst point by using the gravity extraction algorithm based on the matrix, solve the technical problem that the high-speed camera frame frequency is limited and affects the measurement of the instantaneous three-dimensional coordinates of the air burst point, and improve the measurement accuracy of the burst point coordinates. BRIEF DESCRIPTION OF DRAWINGS

[0090] Figure 1 It is the detection system station layout of the present application;

[0091] Figure 2 is the principle of the burst image interpolation of the present application;

[0092] Figure 3 is the flow chart of the algorithm of the present application;

[0093] Figure 4 is the image time relationship diagram of the interpolation algorithm of the present application;

[0094] Figure 5 is the conversion relationship diagram of the camera coordinate system and the world coordinate system of the present application. DETAILED DESCRIPTION

[0095] The present application will be further described in detail below in combination with specific examples, which are an explanation of the present application rather than a limitation.

[0096] Example 1:

[0097] Referring to Figure 1 A burst point instantaneous three-dimensional coordinate detection device, comprising a sky screen trigger device, a test marker, a burst point image processing system, a Beidou timing device and at least two high-speed cameras; at least one high-speed camera is erected on both sides of the terminal trajectory at the station position of the safe area, and is protected by rock mass, so that the pre-burst range of the cannonball is in the intersection detection field area of the high-speed cameras on both sides of the terminal trajectory, the sky screen trigger device is arranged below the pre-trajectory in the safe area 300-500 meters in front of the center position of the high-speed cameras on both sides of the terminal trajectory, at least two groups of test markers are placed at the theoretical burst point, and the coordinates of the test markers are measured, the burst point image processing system and the Beidou timing device are arranged in the safe area outside the burst point, and are protected by rock mass; the high-speed cameras are connected with the sky screen trigger device, the burst point image processing system and the Beidou timing device respectively, and the Beidou timing device is connected with the burst point image processing system. It should be noted that the high-speed cameras are two, one is arranged on each side to form binocular test and improve the accuracy of burst point coordinate measurement.

[0098] The high-speed camera is used for synchronously shooting the sequence image information of the target cannonball in the terminal trajectory from multiple angles and close distances; the screen target trigger device is used for providing a unified trigger signal to the high-speed cameras on both sides of the trajectory, so as to ensure that the high-speed cameras are provided with accurate synchronous starting shooting signals when the cannonball flies through the screen target trigger device, so that the high-speed cameras accurately shoot the image information in the key period before and after the explosion of the cannonball, and the storage capacity of the image information of the high-speed camera is reduced; the test marker is used for providing the high-speed cameras on both sides of the trajectory with known coordinate points before the test starts, and calibrating the internal and external parameters of the high-speed camera and calculating the space coordinates after the test; the burst point image processing system is used for acquiring the cannonball image information before the first frame of the cannonball before explosion and the cannonball fire image information in the first frame of the fire after explosion of the cannonball by using the image frame method, and acquiring the first moment of the fire image information of the cannonball explosion by using the image frame interpolation algorithm combined with the cannonball explosion fireball inflation model, and calculating the burst point space three-dimensional coordinates and the explosion moment information of the cannonball at the first moment of the explosion by using the first moment of the fire image information of the cannonball explosion.

[0099] Referring to Figures 1 to 5 A method for measuring the instantaneous three-dimensional coordinates of an air burst point by using an air burst point instantaneous three-dimensional coordinate detection device, comprising the following steps:

[0100] Step 1): arranging a screen target trigger device, a test marker, a burst point image processing system, a Beidou time unit device and at least two high-speed cameras installed on both sides of the terminal trajectory safety area; and installing the devices to form an air burst point instantaneous three-dimensional coordinate detection device;

[0101] Step 2): when the target cannonball passes through the detection area of the screen target trigger device, the screen target trigger device outputs a trigger signal, and simultaneously starts the high-speed cameras on both sides of the trajectory to collect real-time continuous high-frame frequency video images of the target cannonball, and buffers the collected images to obtain sequence image information of the target cannonball, and sends the obtained sequence image information of the target cannonball to the burst point image processing system;

[0102] Step 3): the burst point image processing system receives the sequence image information of the target cannonball sent by the high-speed camera, and uses a video frame method to extract the image information of the burst point area from the obtained sequence image information of the target cannonball, and then uses a background reduction and morphological filtering method to detect and identify the cannonball image information before the first frame of the cannonball before explosion and the cannonball fire image information in the first frame of the fire after explosion, and calculates the corresponding time T n-1 , T n1 .

[0103] Step 4): The burst point image processing system will detect the image information of the shell before the shell explodes and the image information of the shell fireball after the first frame of explosion, and for each frame time T n-1 , n1 , the frame blending interpolation algorithm in the image interpolation algorithm is adopted, and the shell explosion fireball inflation model is combined to calculate the inserted frame image pixel points, and the intermediate frame image Gd0(u e ,v e ,t0) is generated, that is, the first time of the shell detonation fire image information;

[0104] Step 5): First, analyze the intermediate frame image generated in step 1), there are two cases: 1) After the shell and the first time of the shell detonation fire image frame are mixed, there is no superposition or partial superposition, then the burst point coordinates of the intermediate frame image are the middle points of the shell coordinates and the first time of the shell detonation fire image center coordinates; 2) After the shell and the first time of the shell detonation fire image frame are mixed, the shell target is completely overlapped with the fire image, then the burst point coordinates of the intermediate frame image are the first time of the shell detonation fire image center coordinates;

[0105] Then, according to the analysis result, the first time of the shell detonation fire image information obtained in step 1) is calculated by using the center of gravity coordinate extraction algorithm based on the rectangle to calculate the burst point coordinates(u e ,v e ) of the intermediate frame image Gd0(u p0 ,v p0 ); and the frame time corresponding to the interpolation image is calculated;

[0106] Step 6): According to the test pole image, the camera internal and external calibration parameters are solved, the system calibration data is obtained; by establishing the image pixel coordinate system, the image coordinate system, the camera coordinate system and the world coordinate system, combining the conversion relationship between each coordinate system, solving the space burst point coordinate model, and substituting the burst point coordinates(u e ,v e ) of the intermediate frame image Gd0(u p0 ,v p0 ) obtained in step 2) into the space burst point coordinate model, the space three-dimensional coordinates of the burst point and the explosion time are solved.

[0107] Embodiment 2: An air burst point instantaneous three-dimensional coordinate measurement method using an air burst point instantaneous three-dimensional coordinate detection device, comprising the following steps: the method is specifically:

[0108] The step 1) is specifically: erecting at least one high-speed camera on both sides of the trajectory with tripods at the station position of the safety area of the terminal trajectory, and making rock protection, so that the pre-explosion range of the shell is in the intersection detection field area of the high-speed cameras on both sides of the terminal trajectory, placing the sky screen target trigger device in the safety area under the pre-trajectory 300-500 meters in front of the center position of the high-speed cameras on both sides of the terminal trajectory, placing at least two sets of test markers at the theoretical explosion point, and measuring the coordinates of the test markers, and placing the explosion point image processing system and the Beidou time system device in the safety area outside the explosion point, and making rock protection; the high-speed cameras are connected with the sky screen target trigger device, the explosion point image processing system and the Beidou time system device, and the Beidou time system device is connected with the explosion point image processing system;

[0109] The step 2) is specifically: when the target shell passes through the light curtain formed by the optical lens of the sky screen target trigger device, the light flux on the photosensitive surface of the photoelectric sensor on the optical lens changes due to the shielding of the target shell, the changed light flux is extracted, amplified, noise filtered and processed by a level conversion circuit through an analog circuit, and finally a TTL level signal with a fixed pulse width is output to the high-speed cameras on both sides of the trajectory, the high-speed cameras on both sides of the trajectory are started to collect real-time continuous high-frame frequency video images of the target shell, the collected images are cached to obtain target shell sequence image information, and the obtained target shell sequence image information is sent to the explosion point image processing system;

[0110] The step 3) is specifically:

[0111] extracting the start and end time of the target shell video information before and after the shell explosion from the target shell sequence image information obtained in step 2), and deriving each frame of JPEG image I(u e ,v e ,t) with time mark by video frame processing; obtaining a frame of image before the shell enters the field of view as a background image M bg ((u e ,v e ,t0); performing background subtraction processing on the target shell sequence image information with time mark to extract a frame of shell image information M n-1 (u e ,v e ,t n-1 ) before explosion and a frame of shell fire image information M n1 (u e ,v e ,t n1 ) after explosion, wherein the background subtraction algorithm is:

[0112] M n-1 (u e ,ve t n-1 ) = I(u e ,v e ,t n-1 )-M bg (u e ,v e ,t0)

[0113] M n1 (u e ,v e ,t n1 ) = I(u e ,v e ,t n1 )-M bg (u e ,v e ,t0)

[0114] Then, a gray scale image is set in the multi-gray scale target shell sequence image information after the background reduction processing, and the gray scale image is M(u e ,v e ,t). A gray scale value T is found in the gray scale image M(u e ,v e ,t) as a threshold value, the image is divided into two parts, then the initial multi-gray scale target shell sequence image information is binarized, the threshold value T is determined by using the maximum inter-class variance method, and all pixels of the image are mutually exclusive and divided into an object pixel set G O and a background pixel set G B . It is assumed that the two pixel sets have w O (t) and w B (t) pixels respectively, and the average gray scales of the two pixel sets are μ O (t) and μ B (t) respectively, and the gray scale distribution variances of the two pixel sets are σ O 2 (t) and σ B 2 (t) respectively. The maximum inter-class variance method will find the threshold value T * that makes the inter-class variance minimum, that is:

[0115]

[0116] The pixel point value greater than or equal to T is set to 1, and the pixel value less than the threshold value is set to 0. The binarization process can be expressed by a mathematical expression as follows:

[0117]

[0118] Then, a morphological filtering method is used to process the shell image information Gd' of the frame before explosionn-1 (u e ,v e ,t n-1 ) and the shell flash image information when the first frame after the explosion shows flashes Gd' n1 (u e ,v e ,t n1 The process involves an opening operation filter that first erodes and then dilates to remove small particle noise and smooth the boundaries of the projectile and flash targets without altering their shape or area. This accurately extracts the projectile and flash targets, yielding the projectile image information (Gd) of the frame before detonation. n-1 (u e ,v e ,t n-1 ) and the shell flash image information when the first frame after the explosion shows flashes Gd n1 (u e ,v e ,t n1 ).

[0119] Step 4) specifically refers to:

[0120] The explosion image processing system uses morphologically filtered images of the shell before detonation (Gd) to represent the shell before detonation. n-1 (u e ,v e ,t n-1 ) and the shell flash image when the first frame after the explosion appears Gd n1 (u e ,v e ,t n1 Substituting these values ​​into the frame interpolation algorithm, and combining them with the fireball expansion model of a shell explosion, assuming the weight of the frame before detonation is L-α / L, and the weight of the first frame's fire image after detonation is α / L, the intermediate frame image Gd0(u) is obtained by multiplying the two reference frames by their respective weights and then adding them together. e ,v e ,t0); where the algorithm is as follows:

[0121]

[0122] Where L is the distance between the two original frames, and α is the relative distance between the frame before detonation and the inserted frame;

[0123] The insertion frame time is:

[0124] T n0 =T n-1 +α

[0125] Step 5) Specifically, it involves solving for the coordinates of the explosion point.

[0126] Two position relations of the intermediate frame image obtained in step 4) are judged:

[0127] (1) the superposition or partial superposition of the shell and the fire image, the blast point coordinate of the intermediate frame image is the middle point of the shell coordinate and the center pixel coordinate of the fire image; (2) the complete coincidence of the shell target and the fire image, the blast point coordinate of the intermediate frame image is the center pixel coordinate of the fire image;

[0128] According to the judgment result, the blast point coordinate of the intermediate frame image is calculated by using the center of mass coordinate extraction algorithm based on the matrix, the quality of each pixel in the fire region of the blast point fire image is 1, that is, the quality of each pixel is equal to its pixel value, (u e ,v e ) is the coordinate of the image pixel, and S is the area of the pixel region, then the p+q order moment of the target can be expressed as:

[0129]

[0130] In the formula, M is the moment of the image under different p and q values, f(u e ,v e ) is the quality of a pixel; the zero order moment and the first order moment are calculated respectively, and there are three cases as follows:

[0131] When p=0 and q=0, the zero order moment M(0,0) is:

[0132]

[0133] When p=1 and q=0, the first order moment M(0,1) is:

[0134]

[0135] When p=0 and q=1, the value of the first order moment M(1,0) is:

[0136]

[0137] The center of mass of the target image can be calculated by using the zero order moment and the first order moment, and (u p0 ,v p0 ) represents the blast point coordinate of the intermediate frame image, and the solution algorithm of the blast point coordinate is:

[0138]

[0139] In the formula, M(1,0) represents the sum of the horizontal coordinates of all pixels of the bullet hole, M(0,1) represents the sum of the column coordinates of all pixels of the bullet hole, and M(0,0) represents the number of pixels contained in the bullet hole.

[0140] Step 6) is specifically: solving the spatial burst point coordinate model and bringing the burst point coordinates into the model to solve the spatial three-dimensional coordinates of the burst point:

[0141] Suppose the three-dimensional coordinates of the spatial burst point P in the world coordinate system are (X P ,Y P ,Z P ) and the image coordinates after imaging are (u P ,v P );The linear model of the high-speed camera can be expressed as:

[0142]

[0143] The camera distortion model is as follows:

[0144]

[0145] Wherein, Considering the second-order radial distortion, the distortion coefficients are a1 and a2;λ is the scale factor, (u w ,v w ) is the distortion-free image coordinate, (R, T) is the external parameter of the camera, R and T are the rotation matrix and translation vector of the world coordinate system to the camera coordinate system respectively, and A is the internal parameter matrix of the camera, which can be expressed as:

[0146]

[0147] In the formula, (u0, v0) is the principal point coordinate of the image coordinate system, f x , f y are the scale factors of the u-axis and the v-axis respectively, and α is the non-perpendicular factor of the u-axis and the v-axis;The calibration of the high-speed camera needs to refer to the 5 parameters f x , f y , α, u0 and v0 of the internal parameter matrix of the camera, and the distortion coefficients a1 and a2;

[0148] Before testing, two standard test poles are rotated in multiple directions within the range of the projectile pre-burst point, and multiple standard test pole images in different directions are taken by the high-speed binocular camera;According to the imaging relationship of the feature points on the standard test pole on the binocular camera composed of two high-speed cameras, the 5 parameters of the camera calibration and the camera distortion coefficients are calculated;

[0149] Establish the image pixel coordinate system, the image coordinate system, the camera coordinate system and the world coordinate system;The calculation steps of the conversion between the coordinate systems are as follows:

[0150] 1) Pixel coordinate system and image coordinate system and transformation relationship

[0151] The image pixel coordinate system takes the upper left corner of the image as the coordinate origin, takes the row and column as the u-axis and v-axis directions of its coordinate system respectively, and is a two-dimensional coordinate system in a plane with pixels as the unit. The image size is the image resolution, and the pixel coordinate is the position of the pixel in the image. However, the pixel cannot reflect the physical size of the object in the image, so the image coordinate system is established. The origin of the coordinate system coincides with the intersection between the optical axis of the camera and the imaging plane of the camera photoelectric sensor, the x-axis is parallel to the u-axis of the pixel coordinate system, and the y-axis is parallel to the v-axis of the pixel coordinate system. Assuming that the pixel coordinate of the image center is (u0, v0), the physical size of each pixel on the CCD camera target surface in the x-axis and y-axis directions is dx and dy respectively, the relationship between the pixel coordinate (u, v) and the image coordinate (x, y) is:

[0152] x = udx - u0dx

[0153] y = vdy - v0dy

[0154] Write it in the form of homogeneous coordinates:

[0155]

[0156] Where (u0, v0) is the coordinate of the image center, and 1 / dx, 1 / dy are the sampling frequencies in the x and y directions, i.e. the number of pixels per unit length.

[0157] 2) Camera coordinate system and image coordinate system and transformation relationship

[0158] The camera coordinate system is established on the camera. The coordinate system takes the projection center O c of the optical system as the coordinate origin, takes the Z-axis as the optical axis of the camera, and forms a right-handed coordinate system with the X-axis and Y-axis; the relationship between the object point P (X c ,Y c ,Z c ) in the camera coordinate system and the image point p (x, y) in the image coordinate system is:

[0159] x = fX c / Z c

[0160] y = fY c / Z c

[0161] Write it in the form of homogeneous coordinates:

[0162]

[0163] 3) Camera coordinate system and world coordinate system and transformation relationship

[0164] The measurement coordinate system of the selected control points is the object space coordinate system; the mapping of a point in the world coordinate system to the camera coordinate system is represented by an orthogonal rotation matrix R and a translation matrix T, and the formula is:

[0165]

[0166] The homogeneous coordinate form is written as:

[0167]

[0168] wherein the orthogonal rotation matrix R is the cosine combination of the direction of the camera coordinate system relative to the coordinate axis of the world coordinate system, and the translation matrix T = [t1 t2 t3] T is the coordinate of the camera coordinate system origin in the world coordinate system;

[0169] Combined with the conversion relationship between various coordinate systems, the conversion relationship between the pixel coordinate system and the world coordinate system is as follows:

[0170]

[0171] wherein the value of Z c is 1, wherein s is the coordinate axis inclination parameter, the value is 0 in the ideal case, A is the camera internal parameter matrix, R is the rotation matrix, and T is the translation matrix; the above formula is further solved, and the conversion relationship between the system pixel coordinates and the world coordinate system is:

[0172]

[0173] Let the above formula can be simplified to the following space explosion point coordinate model:

[0174] [X Y Z 1] T =C -1 [u v 1] T (2.13)

[0175] In the formula, (X, Y, Z) is the solved space explosion point coordinate, and the unit is meter; (u, v) is the pixel coordinate, and the unit is pixel;

[0176] wherein the explosion point coordinate (u p0 ,v p0 ) obtained in step 5) is substituted into the above space explosion point coordinate model to obtain the space three-dimensional coordinates (X, Y, Z) of the explosion point at the explosion moment.

[0177] The application provides an air explosion point three-dimensional coordinate detection device and a measurement method based on an image interpolation method.

[0178] The application provides an air explosion point three-dimensional coordinate detection device and a measurement method based on an image interpolation method, solves the problem that the explosion light diffusion speed is very fast, the image information of the initial explosion moment of the explosion fireball cannot be captured due to the limitation of the frame frequency of the high-speed camera, and the image of the explosion fireball in the first frame after explosion is a large fireball, even an irregular fireball, and the like, and the technical problem that the calculation of the instantaneous coordinate of the fireball explosion has a large deviation. The application can generate a coherent intermediate image, predict the light image information of the first moment of the explosion of the explosive, calculate the three-dimensional coordinate of the explosion point space by using a gravity extraction algorithm based on a matrix, solve the technical problem that the measurement of the instantaneous three-dimensional coordinate of the air explosion point is affected by the limitation of the frame frequency of the high-speed camera, and improve the measurement precision of the explosion point coordinate.

[0179] The basic principle and main features of the application and the advantages of the application are shown and described. It should be understood by those skilled in the art that the application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principle of the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the claimed application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A method for instantaneous three-dimensional coordinate measurement of an aerial explosion point, characterized in that, Includes the following steps: Step 1): The explosion point image processing system will detect and identify the shell image information in the frame before the shell explodes but before it detonates, and the shell flash image information in the first frame after the explosion when a flash appears, along with the corresponding time T for each frame. n-1 T n1 The image interpolation algorithm employs a frame hybrid interpolation algorithm, combined with a shell explosion fireball expansion model, to calculate the pixel values ​​of the interpolated frame image and generate the intermediate frame image Gd0(u). e ,v e ,t0), that is, the flash image information at the first moment when the shell detonates; Step 2): For the intermediate frame image Gd0(u) generated in Step 1), e ,v e Analyzing the data, we find two scenarios: 1) When the shell and the first flash image frame at the moment of shell detonation are mixed, there is no overlap or only partial overlap. In this case, the explosion point coordinates of the intermediate frame image are the midpoint between the shell coordinates and the center coordinates of the first flash image at the moment of shell detonation; 2) When the shell and the first flash image frame at the moment of shell detonation are mixed, the shell target completely overlaps with the flash image. In this case, the explosion point coordinates of the intermediate frame image are the center coordinates of the first flash image at the moment of shell detonation. Based on the analysis results, the flash image information at the first moment of shell detonation obtained in step 1) is used to calculate the intermediate frame image Gd0(u) using a moment-based centroid coordinate extraction algorithm. e ,v e The coordinates of the explosion point (u,t0) p0 ,v p0 ); and calculate the frame time of the corresponding interpolated image; Step 3): Calculate the camera's internal and external calibration parameters based on the test benchmark image to obtain system calibration data; by establishing image pixel coordinate system, image coordinate system, camera coordinate system, and world coordinate system, and combining the transformation relationships between these coordinate systems, solve the spatial detonation point coordinate model, and then convert the intermediate frame image Gd0(u) obtained in Step 2) into the model. e ,v e The coordinates of the explosion point (u,t0) p0 ,v p0 Substitute these values ​​into the spatial explosion point coordinate model to solve for the spatial three-dimensional coordinates of the explosion point and the explosion time. Specifically, step 1) is as follows: The explosion image processing system uses morphologically filtered images of the shell before detonation (Gd) to represent the shell before detonation. n-1 (u e ,v e ,t n-1 ) and the shell flash image when the first frame after the explosion appears Gd n1 (u e ,v e ,t n1 Substituting these values ​​into the frame interpolation algorithm, and combining them with the fireball expansion model of a shell explosion, assuming the weight of the frame before detonation is L-α / L, and the weight of the first frame's fire image after detonation is α / L, the intermediate frame image Gd0(u) is obtained by multiplying the two reference frames by their respective weights and then adding them together. e ,v e ,t0); where the algorithm is as follows: Where L is the distance between the two original frames, and α is the relative distance between the frame before detonation and the inserted frame; The insertion frame time is: T n0 =T n-1 +α Step 2) specifically involves: Determine the two positional relationships of the intermediate frame image obtained in step 1): (1) If the shell and the flash image are superimposed or partially superimposed, the explosion point coordinates of the intermediate frame image are the midpoint between the shell coordinates and the center pixel coordinates of the flash image; (2) If the shell target completely overlaps with the flash image, the explosion point coordinates of the intermediate frame image are the center pixel coordinates of the flash image. Based on the judgment results, a moment-based centroid coordinate extraction algorithm is used to calculate the explosion point coordinates of the intermediate frame image. Let the mass of each pixel within the firelight region of the explosion point firelight image be 1, meaning the mass of each pixel is equal to its pixel value. e ,v e Let P be the coordinates of a pixel in the image, and S be the area of ​​the pixel region. Then, the p+q moment of the target can be expressed as: In the formula, M represents the moments of the image at different p and q values, and f(u) e ,v e Let be the quality of a pixel; calculate its zeroth and first moments, with three cases as follows: When p = 0 and q = 0, the zeroth moment M(0,0) can be obtained as: When p = 1 and q = 0, the first moment M(0,1) is: When p = 0 and q = 1, the value of the first moment M(1,0) is: The centroid of the target image can be calculated using the zeroth and first moments, using (u p0 ,v p0 Let ) represent the coordinates of the exploded points in the intermediate frame image. The algorithm for solving the exploded point coordinates is as follows: Where M(1,0) represents the sum of the x-coordinates of all pixels in the bullet hole, M(0,1) represents the sum of the column coordinates of all pixels in the bullet hole, and M(0,0) represents the number of pixels contained in the bullet hole. Step 3) specifically involves: solving the spatial explosion point coordinate model and substituting the explosion point coordinates into it to solve for the three-dimensional spatial coordinates of the explosion point. Assume the three-dimensional coordinates of the spatial explosion point P in the world coordinate system are (X... P ,Y P Z P The coordinates of the image after imaging are (u P ,v P The linear model of a high-speed camera can be expressed as: The camera distortion model is as follows: in, Consider second-order radial distortion with distortion coefficients a1 and a2; λ is a scaling factor, (u w ,v w Let (R, T) be the distortion-free image coordinates, (R, T) be the camera's extrinsic parameters, where R and T are the rotation matrix and translation vector from the world coordinate system to the camera coordinate system, respectively, and A be the camera's intrinsic parameter matrix, which can be represented as: In the formula, (u0, v0) are the coordinates of the principal point in the image coordinate system, and f x f y These are the scale factors for the u-axis and v-axis, respectively, and α is the non-perpendicularity factor for the u-axis and v-axis; high-speed camera calibration should refer to the five parameters f in the camera's internal parameter matrix. x f y α, u0 and v0, and distortion coefficients a1 and a2; Before the test, two standard test rods were rotated in multiple directions within the range of the shell's pre-explosion point. A high-speed binocular camera was used to capture multiple images of the standard test rods moving in different directions at the shell's pre-explosion point. Based on the imaging relationship of the feature points on the standard test rods on the binocular camera composed of two high-speed cameras, the five parameters of the camera calibration and the camera distortion coefficient were calculated. Establish the image pixel coordinate system, image coordinate system, camera coordinate system, and world coordinate system; the transformation steps between these coordinate systems are as follows: 1) Pixel coordinate system and image coordinate system and their transformation relationship The image pixel coordinate system uses the top-left corner of the image as its origin, and the rows and columns as its u-axis and v-axis directions, respectively. This coordinate system is a two-dimensional planar coordinate system with pixels as the unit and the image size as the image resolution. The pixel coordinates are the positions of the pixels in the image. However, pixels cannot reflect the physical size of objects in the image, so an image coordinate system is established. The origin of this coordinate system is located within the pixel coordinate system, coinciding with the intersection of the camera optical axis and the camera's photoelectric sensor imaging plane. Its x-axis is parallel to the u-axis of the pixel coordinate system, and its y-axis is parallel to the v-axis of the pixel coordinate system. Let the pixel coordinates of the image center be (u0, v0), and the physical dimensions of each pixel on the CCD camera target surface in the x-axis and y-axis directions be dx and dy, respectively. Then the relationship between the pixel coordinates (u, v) and the image coordinates (x, y) is as follows: x = udx - u0dx y = vdy - v0dy It can be written in homogeneous coordinate form as follows: Where (u0,v0) are the coordinates of the image center, and 1 / dx and 1 / dy are the sampling frequencies in the x and y directions, respectively, which are the number of pixels per unit length. 2) Camera coordinate system and image coordinate system and their transformation relationship The camera coordinate system is established on the camera, with the optical system projection center O as the reference point. c Using the Z-axis as the origin and the Z-axis as the camera's optical axis, a right-handed coordinate system is formed with the X-axis and Y-axis; the object point P(X) in the camera coordinate system... c ,Y c Z c The relationship between image points p(x,y) in the image coordinate system is as follows: x=fX c / Z c y=fY c / Z c It can be written in homogeneous coordinate form as follows: 3) Camera coordinate system and world coordinate system and their transformation relationship The measurement coordinate system of the control points is selected as the object space coordinate system; the mapping from the point in the world coordinate system to the camera coordinate system is represented by an orthogonal rotation matrix R and a translation matrix T, and its formula is: In homogeneous coordinate form, it can be represented as: Wherein, the orthogonal rotation matrix R is the cosine combination of the directions of the camera coordinate system relative to the world coordinate system coordinate axes, and the translation matrix T = [t1 t2 t3] T These are the coordinates of the camera coordinate system origin in the world coordinate system; Combining the transformation relationships between various coordinate systems, the transformation relationship from the pixel coordinate system to the world coordinate system is obtained as follows: Among them, Z c The value is set to 1, where s is the coordinate axis tilt parameter, which is ideally 0, A is the camera intrinsic parameter matrix, R is the rotation matrix, and T is the translation matrix; further simplifying the above equation, the transformation relationship between system pixel coordinates and world coordinates can be obtained as follows: make The above formula can then be simplified to the following spatial detonation point coordinate model: [X Y Z 1] T =C -1 [u v 1] T (2.13) In the formula, (X,Y,Z) are the coordinates of the spatial explosion point obtained by solving, in meters; (u,v) are the pixel coordinates, in pixels. Among them, the coordinates of the explosion point (u) obtained in step 2) p0 ,v p0 Substituting these values ​​into the spatial detonation point coordinate model above, we obtain the three-dimensional spatial coordinates (X, Y, Z) of the detonation point at the moment of explosion.

2. The method for instantaneous three-dimensional coordinate measurement of the aerial explosion point according to claim 1, characterized in that, The following steps are included before step 1): Step 4): Deploy the sky target triggering device, test benchmark, explosion point image processing system, Beidou timing device, and at least two high-speed cameras installed on both sides of the final ballistic trajectory in the safe area of ​​the final trajectory; and install all the devices to form an instantaneous three-dimensional coordinate detection device for the air explosion point. Step 5): When the target shell passes through the detection area of ​​the sky target triggering device, the sky target triggering device outputs a trigger signal and simultaneously activates the high-speed cameras on both sides of the trajectory to acquire real-time continuous high frame rate video images of the target shell, and caches the acquired images to obtain the target shell sequence image information, and sends the obtained target shell sequence image information to the explosion point image processing system. Step 6): The explosion point image processing system receives the target shell sequence image information sent by the high-speed camera, and extracts the image information of the explosion point area using the video frame segmentation method. Then, it uses background subtraction and morphological filtering methods to detect and identify the shell image information in the frame before the shell explodes (before detonation) and the shell flash image information in the first frame after the explosion (when the flash appears), as well as the corresponding time T for each frame. n-1 T n1 .

3. The method for instantaneous three-dimensional coordinate measurement of the aerial explosion point according to claim 2, characterized in that, Step 4) specifically refers to: At the designated safe location on the final trajectory, at least one high-speed camera is mounted on each side of the trajectory using a tripod, with rock protection in place. The pre-explosion range of the shell is within the intersecting detection field of view of the high-speed cameras on both sides of the final trajectory. The sky-canopy target triggering device is placed in a safe area below the pre-trajectory, 300-500 meters away from the center of the high-speed cameras on both sides of the trajectory. At least two sets of test markers are placed at the theoretical detonation point, and the coordinates of the test markers are measured. The detonation point image processing system and the BeiDou timing device are placed in a safe area outside the detonation point, with rock protection in place. The high-speed cameras are connected to the sky-canopy target triggering device, the detonation point image processing system, and the BeiDou timing device, respectively. The BeiDou timing device is connected to the detonation point image processing system. Step 5) Specifically, when the target projectile passes through the light curtain formed by the optical lens of the celestial target triggering device in the detection area, the light flux reaching the photosensitive surface of the photoelectric sensor on the celestial target optical lens changes because the target projectile blocks part of the light. The changed light flux is extracted, amplified, noise filtered, and processed by the analog circuit through the level conversion circuit. Finally, a fixed pulse width TTL level signal is output and sent to the high-speed cameras on both sides of the trajectory. The high-speed cameras on both sides of the trajectory are activated to perform real-time continuous high frame rate video image acquisition of the target projectile. The acquired images are buffered to obtain the target projectile sequence image information, and the obtained target projectile sequence image information is sent to the explosion point image processing system. Step 6) specifically refers to: Extract the start and end times of the target projectile video information before and after detonation from the target projectile sequence image information obtained in step 5), and use video frame segmentation processing to export each frame of JPEG image I(u) with time stamps. e ,v e ,t); Obtain the image of the frame before the shell enters the field of view as the background image M. bg (u e ,v e ,t0); Background subtraction algorithm is used to subtract background from the target shell sequence image information with time stamps in order to extract the shell image information M of the frame before the explosion. n-1 (u e ,v e ,t n-1 ) and the first frame of the shell flash image information after the explosion M n1 (u e ,v e ,t n1 ), where the background difference algorithm is: M n-1 (u e ,v e ,t n-1 )=I(u e ,v e ,t n-1 )-M bg (u e ,v e ,t0) M n1 (u e ,v e ,t n1 )=I(u e ,v e ,t n1 )-M bg (u e ,v e ,t0) Then, in the target projectile sequence image information after background subtraction processing, a grayscale image is set, and the grayscale image is set as M(u e ,v e ,t), in the grayscale image M(u e ,v e Find a gray value T in the given set (t) as a threshold to segment the image into two parts. Then, binarize the initial multi-gray-level target shell sequence image information, determine the threshold T using the maximum inter-class variance method, and mutually exclusively divide all pixels of the image into object pixel sets G. O and background pixel set G B Assume that each of the two pixel sets has w O (t), w B (t) pixels, each with an average gray level of μ O (t) and μ B (t), and their respective gray-level distribution variances are σ. O 2 (t) and σ B 2 (t), then the maximum between-class variance method will find the threshold T that minimizes the between-class variance. * ,Right now: Pixel values ​​greater than or equal to T are set to 1, and pixel values ​​less than the threshold are set to 0; this binary process can be expressed mathematically as follows: Then, morphological filtering was used to analyze the binarized shell image information Gd' from the frame before the explosion, before detonation. n-1 (u e ,v e ,t n-1 ) and the shell flash image information when the first frame after the explosion shows flashes Gd' n1 (u e ,v e ,t n1 The process involves an opening operation filter that first erodes and then expands to remove small particle noise, smooth the boundaries between the projectile and flash targets without altering their shape or area, and accurately extract the projectile and flash targets, thus obtaining the projectile image information (Gd) of the undetonated frame before the explosion. n-1 (u e ,v e ,t n-1 ) and the shell flash image information when the first frame after the explosion shows flashes Gd n1 (u e ,v e ,t n1 ).

4. An aerial detonation point instantaneous three-dimensional coordinate detection device based on the aerial detonation point instantaneous three-dimensional coordinate measurement method according to any one of claims 1 to 3, characterized in that, The system includes a sky-canopy target triggering device, a test marker, an explosion point image processing system, a BeiDou time synchronization device, and at least two high-speed cameras. At the designated safe location on the final trajectory, at least one high-speed camera is mounted on each side of the trajectory using tripods, with rock protection in place. This ensures the pre-explosion range of the shell is within the intersecting detection field of view of the high-speed cameras on both sides of the final trajectory. The sky-canopy target triggering device is positioned 300-500 meters in front of the center of the high-speed cameras on both sides of the final trajectory, in a safe area below the pre-trajectory. A test marker is placed at the theoretical explosion point, and its coordinates are measured. The explosion point image processing system and the BeiDou time synchronization device are positioned in a safe area outside the explosion point, with rock protection in place. The high-speed cameras are connected to the sky-canopy target triggering device, the explosion point image processing system, and the BeiDou time synchronization device, with the BeiDou time synchronization device connected to the explosion point image processing system.

5. The instantaneous three-dimensional coordinate detection device for aerial explosion points according to claim 4, characterized in that, The test benchmarks are at least two sets of test benchmarks.

6. The instantaneous three-dimensional coordinate detection device for aerial explosion points according to claim 4, characterized in that, The high-speed camera is used to capture sequential image information of the target shell in the final trajectory from multiple angles and at close range simultaneously; the sky target triggering device is used to provide a unified triggering signal to the high-speed cameras on both sides of the trajectory to ensure that the shell provides an accurate synchronous start shooting signal to the high-speed camera when it flies past the sky target triggering device, so that the high-speed camera can accurately capture image information before and after the shell explodes, thereby reducing the storage capacity of the high-speed camera image information. The test benchmark is used to provide known coordinate points for the high-speed cameras on both sides of the trajectory before the test begins, and to calibrate the intrinsic and extrinsic parameters of the high-speed cameras and calculate their spatial coordinates after the test. The explosion point image processing system is used to obtain the shell image information of the target shell sequence image information captured by the high-speed camera by image frame segmentation, which is the shell image information before the shell explodes and the shell flash image information of the first frame after the shell explodes. The system also uses image frame interpolation algorithm combined with the shell explosion fireball expansion model to obtain the flash image information of the first moment when the shell detonates. Using the flash image information of the first moment when the shell detonates, the spatial three-dimensional coordinates of the explosion point and the explosion time information of the first moment when the shell explodes are calculated.

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