Multi-parameter test and three-dimensional reconstruction method and system for fragment field

Abstract

The invention discloses a fragment field multi-parameter test and three-dimensional reconstruction method and system. The method comprises the following steps: S1, arranging a flash target array and a high-speed camera; s2, the warhead is triggered to conduct static explosion, in the whole process from the beginning of the explosion to the end of the explosion, the high-speed camera continuously shoots perforation optical sequence images of the fragments penetrating through the corresponding flash targets, and shot image data are stored; s3, according to the perforation optical sequence images of the fragments penetrating through the corresponding flash targets, fragment parameters and space coordinates of all the perforations are obtained; and S4, performing fragment field three-dimensional scene reconstruction according to the fragment parameters and the space coordinates of the perforations. By adopting the technical scheme of the invention, the technical problems of limited test range, incomplete acquisition of multiple parameters of fragments, low test precision and incapability of realizing three-dimensional replay of the fragment field in the existing fragment field test method in the static explosion test of the explosion-killing warhead are solved.

Description

Technical Field

[0001] This invention belongs to the field of weapon testing and measurement technology, specifically relating to a method and system for multi-parameter testing and three-dimensional reconstruction of fragmentation fields. Background Technology

[0002] As weapon components whose core destructive element is high-speed fragmentation, high-explosive fragmentation warheads directly determine the combat capability of weapon systems and occupy a crucial position in defense equipment development and weapon performance evaluation. Currently, research on high-explosive fragmentation warheads focuses on the quantitative assessment of their destructive effectiveness, with parameters such as the number, momentum, size, scattering angle, and distribution density of fragments being core indicators for measuring their destructive capability. Simultaneously, dynamic three-dimensional reconstruction of the fragmentation field during the explosion can visually present the fragmentation patterns and spatial distribution characteristics, providing important evidence for in-depth analysis of the warhead's damage mechanism. Therefore, efficient and accurate fragmentation field parameter acquisition and three-dimensional reconstruction technologies have become an important research direction in the field of weapon testing. Currently, the main technologies for measuring fragment parameters both domestically and internationally include the target plate method, the laser light curtain method, and the high-speed photography method. The technical characteristics and limitations of each method are as follows: Target plate method: This is a contact measurement technique that involves placing a target plate along the fragment's flight path, collecting fragments that pass through the plate, and then analyzing parameters such as fragment distribution and velocity. This method requires manual retrieval of the target plate and fragment processing, making data acquisition and retrieval time-consuming and labor-intensive. Furthermore, fragments are prone to deformation or damage during collisions with the target plate, leading to significant measurement errors in fragment size and morphology, thus compromising data accuracy. Laser light curtain method: This method uses multiple laser light curtains to form a detection area. The fragment velocity and velocity attenuation coefficient are indirectly calculated by the time difference between fragments passing through different light curtains. However, this method requires extremely high precision in light curtain placement and is easily affected by environmental factors such as explosion shock waves and smoke, resulting in low data acquisition rates. Additionally, it only acquires fragment velocity information and cannot measure the relationship between the fragment's flight trajectory, three-dimensional coordinates, and impact time, resulting in a single dimension of parameter acquisition. High-speed photography methods are divided into two categories: direct photography and indirect photography. Direct photography uses a high-speed camera to directly record the explosion process and fragment movement, enabling non-contact measurement with high accuracy. It can obtain fragment velocity and coordinate parameters, but the equipment is expensive, the data processing algorithm is complex, and a single test can only cover a limited area, making it impossible to achieve comprehensive measurement of large-scale fragments. Indirect photography methods (including impact and perforation methods) use the warhead detonation flash as the start signal and the fragment emission on the target surface as the stop signal. It can only obtain fragment velocity information and cannot obtain key parameters such as the three-dimensional coordinates and distribution density of the fragments, making it difficult to meet the needs of comprehensive fragment field assessment.

[0003] Existing fragment parameter measurement technologies generally suffer from problems such as incomplete parameter acquisition, low measurement accuracy, weak environmental interference resistance, and inability to achieve dynamic three-dimensional reconstruction. There is an urgent need for a technology that can accurately acquire multiple fragment parameters, cover a wide range, and achieve dynamic three-dimensional reconstruction of the fragment field to meet the high-efficiency evaluation requirements of warhead static explosion tests. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method and system for multi-parameter testing and three-dimensional reconstruction of fragmentation fields.

[0005] To achieve the above objectives, the present invention provides the following solution: A method for multi-parameter testing and 3D reconstruction of fragment fields, comprising: Step S1: Deploy the flash target array and high-speed camera; Step S2: Trigger the warhead to perform a static explosion. Throughout the entire process from the start to the end of the explosion, the high-speed camera continuously captures a series of images of the fragments passing through the corresponding flash target and stores the captured image data. Step S3: Based on the perforated optical sequence images of the fragment passing through the corresponding flash target, obtain the fragment parameters and the spatial coordinates of each perforation; Step S4: Reconstruct the three-dimensional scene of the fragment field based on the fragment parameters and the spatial coordinates of each perforation.

[0006] As a preferred option, in the static explosion test area of ​​the explosive warhead, with the explosion center as the center, several flash targets are set up in a fan-shaped or gradient arrangement at a preset distance from the explosion center to form a three-dimensional flash target array.

[0007] Preferably, a high-speed camera is set on the back of each flash target, and the shooting angle and focal length of the high-speed camera are adjusted so that the shooting field of the high-speed camera covers the corresponding flash target.

[0008] Preferably, in step S3, the perforations formed by the fragment passing through the flash target are identified from the perforated optical sequence image of the fragment passing through the corresponding flash target, the coordinate position of each perforation in the image coordinate system is determined, and the image coordinates of the perforations are converted into actual spatial coordinates according to the preset relative positional relationship between the flash target and the high-speed camera.

[0009] Preferably, in step S3, the flight speed of the fragment is calculated based on the spatial coordinates of the same perforation on different flash targets and the time difference of the perforation captured by the high-speed camera, combined with the actual spatial distance between the flash targets; the size and shape of the fragment are estimated by identifying the shape and size of the perforation and combining it with the thickness parameters of the flash targets; the number of perforations on all flash targets is counted, and the total number and distribution density of fragments in the fragment field are estimated by combining it with the coverage of the test system.

[0010] Preferably, in step S4, a kinematic model of the fragment is established based on the fragment's flight speed, flight direction, and the spatial coordinates of each perforation, simulating the flight trajectory of each fragment from the epicenter to passing through each flash target. Based on the actual spatial parameters of the test area, the three-dimensional coordinates of the epicenter, the position and size data of the flash target array, the installation coordinates and internal and external parameters of the high-speed camera are used as basic inputs and mapped to the same three-dimensional coordinate system through a coordinate unification algorithm. Then, the flight trajectory and size and shape parameters of the fragment are incorporated to generate a corresponding scale epicenter marker model, flash target solid model, camera simplified model, and fragment geometric model, which are integrated to form a three-dimensional scene consistent with the actual test scene.

[0011] This invention also provides a fragmentation field multi-parameter testing and three-dimensional reconstruction system, comprising: The first processing module is used to deploy the flash target array and the high-speed camera; The second processing module is used to trigger the warhead to detonate statically. Throughout the entire process from the start to the end of the explosion, the high-speed camera continuously captures the perforated optical sequence images of the fragments passing through the corresponding flash target and stores the captured image data. The third processing module is used to obtain the fragment parameters and the spatial coordinates of each perforation based on the perforation optical sequence image of the fragment passing through the corresponding flash target; The fourth processing module is used to reconstruct the three-dimensional scene of the fragment field based on the fragment parameters and the spatial coordinates of each perforation.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: By processing a sequence of images of a target plate perforated by fragments during the explosion of a fragmentation warhead, fragmentation field parameters are obtained, and dynamic three-dimensional reconstruction of the fragmentation field is performed. Its technical advantages are as follows: 1. Parameters are accurate in multiple aspects. Traditional methods suffer from single parameters and large errors (e.g., the target plate method has an error exceeding 15%). This invention combines multi-target three-dimensional arrangement (capture rate > 90%) with image correction (error < 1 mm) to simultaneously acquire multiple parameters such as fragment coordinates, velocity, size, and kinetic energy. 2. High testing efficiency Traditional processing requires 1-2 days and repeated testing. This invention's wireless transmission and automation algorithm completes testing and data processing within 2 hours, improving efficiency by more than 10 times. 3. Strong anti-interference capability Laser methods suffer from low data rates (60%-70%) and camera damage rates (>30%). This invention uses an underground-buried camera for non-contact imaging, resulting in a low equipment damage rate and a data acquisition rate >95%. 4. Dynamic visualization advantages Traditional methods only output parameter tables, leading to subjective evaluation. This invention uses 3D modeling to generate dynamic trajectories, improving evaluation efficiency by several times and accuracy by 60%. Attached Figure Description To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a flowchart of the fragment field multi-parameter testing and three-dimensional reconstruction method according to an embodiment of the present invention; Figure 2 A schematic diagram (top view) of the flash target array fan-shaped arrangement and data acquisition system structure. Figure 3 A schematic diagram (top view) of the gradient arrangement of the flash target array and the data acquisition system. Figure 4 A schematic diagram (front view) of a cross-sectional structure for a single flash target and a high-speed camera in combination. Figure 5 The diagram shows the three-dimensional dynamic replay effect of the fragment field generated by the PyQt5 host computer; where (a) is the host computer software and (b) is the three-dimensional dynamic replay effect of the fragments. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] Example 1 like Figure 1 As shown, this invention provides a method for multi-parameter testing and three-dimensional reconstruction of fragment fields, including: Step 1. Test System Setup Flash target array arrangement: In the static explosion test area of ​​the high-explosive warhead, several flash targets are arranged in a fan-shaped or gradient pattern at a predetermined distance from the explosion center, forming a three-dimensional flash target array. In the fan-shaped arrangement, the planes containing the flash targets are distributed in a fan shape around the explosion center, and the angle between adjacent flash targets is set according to the required test accuracy. Figure 2This is a schematic diagram of the fan-shaped arrangement of the flash target array and the data acquisition system. A top-down view visually illustrates the relationship between the flash center, target positions, and cameras in the fan-shaped distribution. In a gradient arrangement, each flash target is positioned in layers or segments at preset intervals along a direction perpendicular to the flash center axis or along a specific spatial trajectory, ensuring that the flash target array can fully cover the spatial range where fragments may fly. Figure 3 This is a schematic diagram of the gradient arrangement of the flash target array and the data acquisition system, showing the layered / segmented three-dimensional coverage structure through a top view. High-speed camera setup: One high-speed camera is positioned on the back of each flash target (i.e., the side opposite the epicenter). The shooting angle and focal length of the high-speed camera are adjusted to ensure that the camera's field of view completely covers the corresponding flash target, ensuring clear capture of the perforation image formed when the fragment passes through the flash target. The frame rate of the high-speed camera is set according to the estimated flight velocity of the fragment to ensure the capture of the complete optical sequence of images of the fragment passing through the flash target. Figure 4 This is a cross-sectional diagram of a single flash target and a high-speed camera arranged together. The cross-sectional diagram shows the relative positions of the back of the flash target and the camera, as well as the coverage of the field of view.

[0017] Step 2. Implementation of the testing process All high-speed cameras are activated by a synchronous trigger, and the high-speed cameras are set to continuous shooting mode, recording the start time of shooting; the warhead is triggered to perform a static explosion, and throughout the entire process from the start to the end of the explosion, the high-speed cameras continuously capture images of the perforated optical sequence of fragments passing through the corresponding flash target, and store the captured image data.

[0018] Step 3. Multi-parameter calculation of fragments Image data preprocessing: Preprocessing of the perforated optical sequence images captured by the high-speed camera, including image denoising (using algorithms such as Gaussian filtering and median filtering to remove image noise), image enhancement (highlighting the perforated area through operations such as contrast adjustment and edge enhancement), and image correction (eliminating the influence of camera lens distortion and shooting angle deviation on the image).

[0019] Perforation identification and localization: Image recognition algorithms (such as threshold segmentation algorithm, edge detection algorithm, and small target detection algorithm combined with deep learning) are used to identify the perforations formed by fragments passing through the flash target from the preprocessed image, determine the coordinate position of each perforation in the image coordinate system, and convert the image coordinates of the perforations into actual spatial coordinates according to the preset relative positional relationship between the flash target and the high-speed camera.

[0020] Fragment parameter calculation: Based on the spatial coordinates of the same fragment perforation on different flash targets and the time difference of the perforation captured by the high-speed camera, combined with the actual spatial distance between flash targets, the flight velocity of the fragment (including velocity magnitude and velocity direction) is calculated using kinematic formulas; by identifying the shape and size of the perforation, combined with parameters such as the thickness of the flash targets, the size and shape of the fragment are estimated; the number of perforations on all flash targets is counted, and combined with the coverage of the test system, the total number and distribution density of fragments in the fragment field are estimated. Step 4. 3D Replay of the Fragmented Scene Fragment trajectory reconstruction: Based on the calculated fragment flight velocity, flight direction and spatial coordinates of each perforation, a kinematic model of the fragment is established to simulate the flight trajectory of each fragment from the explosion center to passing through each flash target.

[0021] 3D scene construction: Based on the actual spatial parameters of the test area, the 3D coordinates of the explosion center, the position and size data of the flash target array, the installation coordinates and internal and external parameters of the high-speed camera are used as basic inputs and mapped to the same 3D coordinate system through a coordinate unification algorithm. Then, the motion trajectory data and size and shape parameters of the fragments are integrated to generate a corresponding scaled explosion center marker model, flash target entity model, camera simplified model and fragment geometric model, and integrate them to form a 3D scene consistent with the actual test scene.

[0022] Dynamic replay generation: Based on the trajectory and time sequence of the fragments, the entire motion process of the fragments from the start of the explosion to the end of the flight is simulated in a 3D model, generating a 3D dynamic replay animation of the fragment field, realizing the visualization of the spatial distribution of the fragment field.

[0023] As one embodiment of the present invention, the test system parameters are set in step 1 as follows: Flash target parameters: Use metal foil (such as aluminum foil or copper foil) with a thickness of 0.5-2mm as the flash target material. The size of the flash target is set according to the test area space and the field of view of the high-speed camera. For example, use a rectangular target surface of 1.2m×3m. Spray a high-contrast coating (such as black coating) on ​​the surface of the flash target to facilitate subsequent identification of the perforated area. Arrangement parameters: Set the minimum distance between the explosion center and the flash target array to 5-10m, and adjust according to the estimated fragment flight distance of the warhead; when arranged in a fan shape, set the included angle between adjacent flash targets to 10-30°, and set a total of 6-12 flash targets to form a fan-shaped coverage of 360° or a specific angle range; when arranged in a gradient, set 3-5 layers of flash targets at intervals of 2-5m along the direction perpendicular to the explosion center axis, with 4-6 flash targets in each layer to ensure three-dimensional coverage. High-speed camera parameters: Select a high-speed camera with a resolution of no less than 1280×1024 pixels and a frame rate of no less than 8000fps. Select a fixed-focus lens with a focal length of 50-100mm. Adjust the distance between the camera and the flash target to 3-5m to ensure complete imaging of the target surface and that the pixel accuracy of the punched image is no less than 0.1mm / pixel. In one embodiment of the present invention, in step 2, a flash target array and a high-speed camera system with the above parameters are set up at the test site. The distance between the explosion center and each flash target is calibrated using a laser rangefinder, and the verticality of the flash targets and the shooting angle of the high-speed cameras are adjusted using a level to ensure the accuracy of the system layout. All high-speed cameras are started, and the camera shooting frame rate is set to 8000fps with a resolution of 1280×1024 pixels. The camera start shooting time (t0) is recorded. The warhead is detonated using a detonator. Depending on the warhead yield, the high-speed camera recording is triggered by either breaking or passing through the target. After the warhead explodes, fragments fly in all directions, passing through each flash target and forming holes. The high-speed camera continues to shoot until 5-10 seconds after the explosion ends, then stops shooting and stores all image data.

[0024] As one embodiment of the present invention, step 3 includes: 1. Image preprocessing: The captured images are processed using a median filtering algorithm to remove noise (filter window size is 3×3), the image contrast is adjusted by histogram equalization, and the image distortion is corrected using a lens distortion correction algorithm (based on camera intrinsic calibration data).

[0025] 2. Punchhole Recognition and Localization: An adaptive threshold segmentation algorithm is used. First, the grayscale image is read, and the grayscale value I of each pixel is obtained. gray Take an N×N local window centered at pixel (u, v), calculate the Gaussian weighted mean of gray levels T(u, v) within the window, set an offset C, and press I. bin (u, v) = 0 (perforation: I) gray ≤T(u,v)-C),I bin (u, v) = 255 (Background: I) gray >T(u,v)-C) to obtain a binary image, after optimization by erosion and dilation morphological operations, the single-pixel edge contours of the perforation {(u1,v1),...,(u n ,v n Then calculate the zeroth moment of the profile. First moment and , obtain the center coordinates of the image coordinate system , Finally, combining the camera's intrinsic parameters (including focal length f and principal point coordinates (u0, v0)) and the vertical distance d between the camera and the target surface, the perspective projection formula is used. , , The actual spatial coordinates (x, y, z) of the perforation center are calculated.

[0026] 3. Fragment Parameter Calculation: Assuming the time it takes for a fragment to be photographed at the epicenter (spatial coordinates (x1, y1, z1)) is t1, and the time it takes for it to be photographed through the blast target (spatial coordinates (x2, y2, z2)) is t2, then the magnitude of the fragment's flight velocity... The velocity direction is determined by the vector (x2-x1, y2-y1, z2-z1); it is determined by the conversion ratio k between the image pixel size and the actual physical size. The maximum pixel diameter D of the perforation measured in the image. img,max Minimum pixel diameter D img,min Convert to actual size: D max =D img,max ×k、D min =D img,min ×k, take the arithmetic mean of the two. Estimate fragment size; count the total number of effective perforations N on all flash targets, filter connected regions with an area greater than a set threshold to eliminate noise, calculate the actual physical area S0 of a single flash target = target length × target width, combine the number of target surfaces M in the flash target array to obtain the total coverage area S = S0 × M, and finally calculate the fragment distribution density by ρ = N / S.

[0027] As one embodiment of the present invention, in step 4, a self-developed 3D modeling software based on PyQt5 is used to import a 3D model of the test site (including the ground, the explosion center location marker, and the flash target array model). The spatial coordinates, flight velocity, and size of each fragment are input into the model. The flight trajectory of the fragments is simulated based on Newton's laws of motion. The animation timeline is set to be synchronized with the actual explosion time, generating a 3D dynamic replay video of the fragment field from the start of the explosion to the stabilization of the fragment flight. The spatial distribution of the fragment field at different angles can be viewed by dragging and zooming with the mouse. Figure 5 This is a schematic diagram of the 3D dynamic replay effect of the fragmentation field generated by the PyQt5 host computer. The diagram shows the actual effect of the 3D replay, and marks elements such as the explosion center, fragments, and target to verify the visualization effect of the text description.

[0028] This invention integrates fragment motion trajectory reconstruction algorithm, 3D scene construction, and dynamic replay rendering into one system, realizing fully automated processing from fragment parameter input, trajectory calculation, scene modeling to dynamic replay, supporting data interaction and visualization operation, and improving the efficiency and convenience of fragment field 3D replay.

[0029] Example 2 This invention also provides a fragmentation field multi-parameter testing and three-dimensional reconstruction system, comprising: The first processing module is used to deploy the flash target array and the high-speed camera; The second processing module is used to trigger the warhead to detonate statically. Throughout the entire process from the start to the end of the explosion, the high-speed camera continuously captures the perforated optical sequence images of the fragments passing through the corresponding flash target and stores the captured image data. The third processing module is used to obtain the fragment parameters and the spatial coordinates of each perforation based on the perforation optical sequence image of the fragment passing through the corresponding flash target; The fourth processing module is used to reconstruct the three-dimensional scene of the fragment field based on the fragment parameters and the spatial coordinates of each perforation.

[0030] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for multi-parameter testing and three-dimensional reconstruction of fragment fields, characterized in that, include: Step S1: Deploy the flash target array and high-speed camera; Step S2: Trigger the warhead to perform a static explosion. Throughout the entire process from the start to the end of the explosion, the high-speed camera continuously captures a series of images of the fragments passing through the corresponding flash target and stores the captured image data. Step S3: Based on the perforated optical sequence images of the fragment passing through the corresponding flash target, obtain the fragment parameters and the spatial coordinates of each perforation; Step S4: Reconstruct the three-dimensional scene of the fragment field based on the fragment parameters and the spatial coordinates of each perforation.

2. The fragment field multi-parameter testing and three-dimensional reconstruction method as described in claim 1, characterized in that, In the static explosion test area of ​​the high-explosive warhead, several flash targets are set up at a predetermined distance from the explosion center in a fan-shaped or gradient arrangement to form a three-dimensional flash target array.

3. The fragment field multi-parameter testing and three-dimensional reconstruction method as described in claim 2, characterized in that, A high-speed camera is set up on the back of each flash target. The shooting angle and focal length of the high-speed camera are adjusted so that the shooting field of the high-speed camera covers the corresponding flash target.

4. The fragment field multi-parameter testing and three-dimensional reconstruction method as described in claim 3, characterized in that, In step S3, the perforations formed by the fragment passing through the corresponding flash target are identified from the perforated optical sequence image of the fragment passing through the flash target. The coordinate position of each perforation in the image coordinate system is determined, and the image coordinates of the perforations are converted into actual spatial coordinates according to the preset relative positional relationship between the flash target and the high-speed camera.

5. The fragment field multi-parameter testing and three-dimensional reconstruction method as described in claim 4, characterized in that, In step S3, the flight speed of the fragment is calculated based on the spatial coordinates of the same perforation on different flash targets and the time difference of the perforation captured by the high-speed camera, combined with the actual spatial distance between the flash targets; the size and shape of the fragment are estimated by identifying the shape and size of the perforation and combining it with the thickness parameters of the flash targets; the number of perforations on all flash targets is counted, and the total number and distribution density of fragments in the fragment field are estimated by combining it with the coverage of the test system.

6. The fragment field multi-parameter testing and three-dimensional reconstruction method as described in claim 5, characterized in that, In step S4, a kinematic model of the fragment is established based on the fragment's flight speed, flight direction, and spatial coordinates of each perforation, simulating the flight trajectory of each fragment from the epicenter to passing through each flash target. Based on the actual spatial parameters of the test area, the three-dimensional coordinates of the epicenter, the position and size data of the flash target array, the installation coordinates and internal and external parameters of the high-speed camera are used as basic inputs and mapped to the same three-dimensional coordinate system through a coordinate unification algorithm. Then, the flight trajectory and size and shape parameters of the fragment are incorporated to generate a corresponding scale epicenter marker model, flash target solid model, camera simplified model, and fragment geometric model, which are integrated to form a three-dimensional scene consistent with the actual test scene.

7. A fragmentation field multi-parameter testing and three-dimensional reconstruction system, characterized in that, include: The first processing module is used to deploy the flash target array and the high-speed camera; The second processing module is used to trigger the warhead to detonate statically. Throughout the entire process from the start to the end of the explosion, the high-speed camera continuously captures the perforated optical sequence images of the fragments passing through the corresponding flash target and stores the captured image data. The third processing module is used to obtain the fragment parameters and the spatial coordinates of each perforation based on the perforation optical sequence image of the fragment passing through the corresponding flash target; The fourth processing module is used to reconstruct the three-dimensional scene of the fragment field based on the fragment parameters and the spatial coordinates of each perforation.

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