Time / space domain combined light curtain projectile identification method for testing intensity of high-speed rotating tube gun

Abstract

The invention relates to the technical field of photoelectric testing of ballistic parameters outside a target range, in particular to a time / space domain combined light curtain projectile identification method for testing the intensity of a high-speed rotating tube gun. The method comprises the following steps of: 1, forming a time / space domain combined light curtain by adopting a six-light curtain array and two linear array cameras; collecting curtain passing signals when the multiple projectiles pass through the time domain light curtain, extracting curtain passing time values, and obtaining projectile images in the two linear array cameras when the multiple projectiles pass through the spatial domain light curtain and time information when the multiple projectiles pass through the spatial domain light curtain; and acquiring the number of projectile shadows at the same moment in the projectile image, and calculating the target landing coordinates of the projectile by adopting different methods according to the number of shadows at the same moment. According to the invention, the spatial position of the projectile can be accurately given, the time measurement error is avoided, and the coordinate measurement precision is higher; the time value output by the time domain light curtain is more direct and accurate than the time value output by the time domain light curtain; the airspace light curtain can distinguish the curtain passing states of the multiple projectiles, and the problem of time value matching when the overlapped projectiles pass through the airspace light curtain is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric testing of ballistic parameters outside a shooting range, and in particular to a time / space domain combined light curtain projectile identification method for density testing of a high-speed rotary cannon. Background Art

[0002] High-speed rotary cannon is an important short-range defense weapon and equipment, and the projectile shooting density parameter is a key parameter for evaluating the performance of this type of weapon. The main methods for testing projectile shooting density include acoustic method, light curtain array method, dual-line array camera intersection method, etc. These methods can measure the target coordinates of single or multiple projectiles that pass through the light curtain one after another, but they are ineffective for high-speed rotary cannons that fire projectiles continuously or simultaneously. High-speed rotary cannons fire a large number of projectiles at the same time in a short period of time, and with a certain spatial dispersion, resulting in mutual occlusion and overlap between projectiles, making it impossible for existing testing methods to effectively test the target coordinates of each projectile.

[0003] The acoustic method uses an acoustic sensor array to measure the arrival time difference of the supersonic projectile shock wave to complete the target coordinate measurement of the supersonic projectile. However, due to the limitations of the acoustic detector, it is only suitable for close-range measurement of supersonic targets. It is also affected by many meteorological conditions, has poor anti-interference ability, and has low measurement accuracy.

[0004] The light curtain array method measures the projectile's target coordinates, flight speed, direction and other ballistic parameters based on the time information of the projectile passing through multiple light curtains arranged in a geometric relationship. For example, in the document with patent number "CN202110432263.X", the "Multi-detection light curtain array spatiotemporal constraint multi-projectile parameter matching method" proposed uses the correlation of the projectile signal waveform output by the parallel detection light curtain to solve the signal waveform attribution problem of the same projectile, thereby identifying the actual curtain-passing moment sequence of each projectile and calculating the projectile flight parameters. However, this method relies on the projectile signal waveform and cannot identify multiple projectiles that pass through the light curtain at the same time. This is because: when multiple projectiles pass through the detection light curtain at the same time, there is only one projectile signal waveform. At the same time, the sequence numbers of the moment values ​​in other light curtains are not completely consistent with the projectile sequence, and even multiple projectiles pass through the same detection light curtain at the same time, resulting in multiple combinations of the moment sequences of multiple projectiles passing through the light curtain array, including false moment sequences, and the light curtain array itself cannot identify the actual moment sequence of each projectile from these moment sequences, so that the flight parameters of multiple projectiles passing through the light curtain array cannot be effectively tested.

[0005] The dual-line array camera intersection method obtains the passing image of the flying projectile passing through the intersection detection surface of the two line array cameras, calculates the central pixel number of the projectile shadow, and solves the target coordinates of the projectile. According to the binocular intersection measurement principle, in the multi-projectile passing image collected by each camera in the dual-line array camera intersection method, the central pixel of each projectile shadow that hits the target at the same time is not one-to-one corresponding. N projectiles passing through the screen at the same time can calculate N2 target coordinates, of which N are true coordinates, (N 2 -N) are false coordinates, so the dual-line camera intersection method cannot identify and distinguish between real or false target coordinates, nor can it identify multiple projectiles passing through the light curtain at the same time.

[0006] In summary, the existing technologies are unable to identify multiple projectiles that pass through the light curtain at the same time, and are unable to effectively test the target coordinates of each projectile. Summary of the invention

[0007] The purpose of the present invention is to provide a time / space domain combined light curtain projectile recognition method to solve the problems in the prior art that multiple projectiles passing through the light curtain at the same time cannot be identified, the target coordinates of each projectile cannot be effectively tested, and thus it is difficult to accurately test the shooting density of a high-speed rotary gun.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a time / space domain combined light curtain projectile identification method, comprising the following steps:

[0009] Step 1: Use a six-light curtain array and two linear array cameras to form a time / space domain combined light curtain: the detection light curtain formed by the six-light curtain array is called a time domain light curtain, and the detection light curtain formed by the intersection of the two linear array cameras is called a space domain light curtain. The time domain light curtain and the space domain light curtain are placed along the trajectory line;

[0010] Step 2: Collect the curtain passing signals of multiple projectiles passing through the time domain light curtain and extract the curtain passing time value, obtain the projectile images in the two line array cameras when the multiple projectiles pass through the space domain light curtain and the time information of the multiple projectiles passing through the space domain light curtain;

[0011] Step 3: Obtain the number of projectile shadows at the same time in the projectile image, and calculate the target coordinates of the projectile using different methods according to the number of shadows at the same time:

[0012] When the number of shadows on the image at the same time is less than or equal to 1, multiple projectiles successively pass through the airspace light curtain, and the target coordinates of the projectiles are calculated using a dual-line array camera intersection measurement method;

[0013] When the number of shadows on the image at the same time is greater than 1, multiple projectiles pass through the spatial light curtain at the same time. The moment information of the multiple projectiles passing through the spatial light curtain and the moment information of the temporal light curtain are used to calculate the target coordinates of each projectile and identify the multiple projectiles.

[0014] Furthermore, in the above step 3, the steps of using the dual-line array camera intersection to measure the projectile target coordinates are as follows:

[0015] Step (1): Obtain the structural parameters of the dual-line array camera, such as the camera horizontal angle, pixel spacing, and lens focal length;

[0016] Step (2): Read the projectile images in the two linear array cameras when the multiple projectiles pass through the airspace light curtain, and extract the central pixel number of each projectile in the image;

[0017] Step (3): Substituting the structural parameters of the linear array camera and the central pixel number of the projectile image into the double linear array camera intersection target coordinate measurement formula to calculate the target coordinate of each projectile;

[0018] Furthermore, in the above step 3, the steps of identifying multiple projectiles are as follows:

[0019] Step (1): obtaining the structural parameters of the time domain light curtain, including the angles of six detection light curtains and the distances between the intersection points of the light curtains;

[0020] Step (2): obtaining the time value of multiple projectiles passing through the time domain light curtain and the time value obtained from the projectile image in the space domain light curtain;

[0021] Step (3): according to the time value when the projectile passes through the six detection light curtains and one spatial light curtain of the time domain light curtain, combined with the plane equations of the seven light curtains, establish the projectile trajectory straight line equation;

[0022] Step (4): Arrange and combine the time values ​​of the projectile passing through the six detection light curtains and one spatial light curtain in the time domain light curtain to obtain all possible passing time sequences of multiple projectiles passing through the seven light curtains;

[0023] Step (5): Substituting the transition moment sequence into the trajectory straight line equation, and calculating the trajectory straight line corresponding to each moment sequence;

[0024] Step (6): According to the positional relationship of the two spatial straight lines being parallel or overlapping, the sequence of the passing moments of the projectiles is matched, the false target coordinates in the spatial light curtain are eliminated, and multiple projectiles are identified.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention utilizes the image information of the projectile passing through the airspace light curtain provided by the airspace light curtain, which can accurately give the spatial position of the projectile, avoid timing errors, and achieve higher coordinate measurement accuracy.

[0027] 2. The present invention utilizes the information of the time when the projectile passes through the airspace light curtain to eliminate the false time sequence of the projectile passing through the time domain light curtain, thereby identifying multiple projectiles. Compared with the existing method of using a multi-light curtain array to identify multiple projectiles, the time value provided by the airspace light curtain in the present invention is obtained through the image of the projectile passing through the curtain, which is more direct and accurate than the time value output by the time domain light curtain.

[0028] 3. The airspace light curtain can distinguish the passing status of multiple projectiles. When multiple projectiles pass through the airspace light curtain at the same time, the airspace light curtain provides only one time value. In other states of multiple projectiles, the number of time values ​​provided by the airspace light curtain is equal to the number of projectiles, avoiding the problem of matching the time values ​​of overlapping projectiles passing through the airspace light curtain. When multiple projectiles pass through the airspace light curtain one after another, the airspace light curtain can directly measure the target coordinates of each projectile; when multiple projectiles pass through the airspace light curtain at the same time, the time value output by the airspace light curtain is combined with the time value output by the time domain light curtain, and according to the spatial position relationship of the projectile trajectory straight line, the false target coordinates in the airspace light curtain are eliminated, thereby identifying multiple projectiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the time / space domain combined light curtain projectile recognition process of the present invention;

[0030] Figure 2 A schematic diagram of the structure of a time / space domain combined light curtain provided in an embodiment of the present invention;

[0031] Figure 3 Schematic diagram b of the time / space domain combined light curtain structure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The design scheme of the embodiment of the present invention will be described in detail below in conjunction with the accompanying drawings of the present invention.

[0033] Reference Figure 1 The present invention provides a time / space domain combined light curtain projectile recognition method, comprising the following steps:

[0034] Step 1: Use a six-light curtain array and two linear array cameras to form a time / space domain combined light curtain: the detection light curtain formed by the six-light curtain array is called the time domain light curtain, and the detection light curtain formed by the intersection of the two linear array cameras is called the space domain light curtain;

[0035] Reference Figure 2 and Figure 3 The specific steps for building the time / space domain combined light curtain are as follows:

[0036] Step (a): construct detection light curtains G1, G2, G3, G4, G5 and G6. G1, G2 and G3 form the first group of detection light curtains, and G4, G5 and G6 form the second group of detection light curtains. The structures of the two groups of detection light curtains are exactly the same. Each detection light curtain can provide information on the moment when the projectile passes through the light curtain, which is called a time domain light curtain. The angle between G1 and G3 and the vertical plane of the predetermined trajectory is α, and the angle between G2 and the vertical plane of the predetermined trajectory is β. The three detection light curtains G1, G2 and G3 intersect at one point, and the distance between the intersection with G4, G5 and G6 is S, which is called the target distance;

[0037] Build two line array cameras, which are placed facing each other at an angle of α0. The line array cameras can provide the time information and image information of the flying projectile passing through the curtain. The detection plane formed by the intersection of the two line array cameras is called the airspace light curtain. The airspace light curtain is perpendicular to the trajectory line. The vertical distance between the center of the light curtain and the intersection of the time domain light curtain is S0. The airspace light curtain and the time domain light curtain together constitute a time / space domain combined light curtain;

[0038] Step (ii): placing the time-domain light curtain and the space-domain light curtain along the trajectory line, with the direction along the trajectory line as the x-axis, the vertical trajectory line upward as the y-axis, the direction of the line connecting the two linear array cameras as the z-axis, and the center of the space-domain light curtain as the origin, establishing a spatial rectangular coordinate system according to the right-hand rule, and the coordinate systems of the time-domain light curtain and the space-domain light curtain coincide with each other;

[0039] Step 2: Collect the curtain passing signals of multiple projectiles passing through the time domain light curtain and extract the curtain passing time value, obtain the projectile images in the two line array cameras when the multiple projectiles pass through the space domain light curtain and the time information of the multiple projectiles passing through the space domain light curtain;

[0040] Step 3: Obtain the number of projectile shadows at the same time in the projectile image, and calculate the target coordinates of the projectile using different methods according to the number of shadows at the same time:

[0041] (i) When the number of shadows on the image at the same time is less than or equal to 1, multiple projectiles successively pass through the airspace light curtain, and the target coordinates of the projectiles are calculated using a dual-line array camera intersection measurement method. The specific steps are as follows:

[0042] Step (1): Obtain the structural parameters of the dual-line array camera, such as the camera horizontal angle, pixel spacing, and lens focal length;

[0043] Step (2): Read the projectile images in the two linear array cameras when the multiple projectiles pass through the airspace light curtain, and extract the central pixel number of each projectile in the image;

[0044] Step (3): Substituting the structural parameters of the linear array camera and the central pixel number of the projectile image into the double linear array camera intersection target coordinate measurement formula to calculate the target coordinate of each projectile;

[0045] The coordinate measurement formula of the dual-line array camera intersection target is as shown in formula (1):

[0046]

[0047] Among them, α0 is the horizontal angle between the two linear array cameras, f1 and f2 are the focal lengths of the two linear array camera lenses, c1 and c2 are the pixel intervals of the photosensitive devices of the two linear array cameras, (x, y) is the target coordinate of any projectile in the airspace light curtain, (x 01 ,y 01 ) and (x02 ,y 02 ) are the coordinates of the principal points of the two linear array camera lenses, z 01 and z 02 are the pixel numbers of the lens principal point in the two line array camera images, z1 and z2 are the center pixel numbers of the projectile shadow in the two line array camera images;

[0048] (ii) When the number of shadows on the image at the same time is greater than 1, multiple projectiles simultaneously pass through the airspace light curtain. The time information of the multiple projectiles passing through the airspace light curtain and the time information of the time domain light curtain are used to calculate the target coordinates of each projectile and identify the multiple projectiles. The specific steps are as follows:

[0049] Step (1): obtaining the structural parameters of the time domain light curtain, including the angles of the six time domain light curtains and the distances between the intersection points of the light curtains;

[0050] Step (2): obtaining the time value of multiple projectiles passing through the time domain light curtain and the time value obtained from the projectile image in the space domain light curtain;

[0051] Step (3): according to the time value when the projectile passes through the six detection light curtains and one spatial light curtain of the time domain light curtain, combined with the plane equations of the seven light curtains, establish the projectile trajectory straight line equation;

[0052] Step (4): Arrange and combine the time values ​​of the projectile passing through the six detection light curtains and one spatial light curtain in the time domain light curtain to obtain all possible passing time sequences of multiple projectiles passing through the seven light curtains;

[0053] Step (5): Substituting the transition moment sequence into the trajectory straight line equation, and calculating the trajectory straight line corresponding to each moment sequence;

[0054] Step (6): According to the positional relationship of the two spatial straight lines being parallel or overlapping, the passing time sequence of the projectiles is matched, the false target coordinates in the spatial light curtain are eliminated, and multiple projectiles are identified;

[0055] The matrix expression of the trajectory equation of the projectile is shown in formula (2):

[0056]

[0057] Among them, a i , b i , c i , d i is the coefficient of the plane equation of the time domain light curtain, which can be calculated from the structural parameters of the time domain light curtain, i=1,2,…,6 represents the serial number of the detection light curtain; T i Indicates the time value when the projectile passes through the six light curtains, T1~T6 is called a time sequence; x1, y1, z1, v x,v y ,v z These six parameters are the parameters of the projectile trajectory.

[0058] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A time / space domain combined light curtain projectile identification method for high-speed rotary gun density test, characterized in that: The following steps are involved: Step 1: Use a six-light curtain array and two linear array cameras to form a time / space domain combined light curtain: the detection light curtain formed by the six-light curtain array is called a time domain light curtain, and the detection light curtain formed by the intersection of the two linear array cameras is called a space domain light curtain. The time domain light curtain and the space domain light curtain are placed along the trajectory line; Step 2: Collect the curtain passing signals of multiple projectiles passing through the time domain light curtain and extract the curtain passing time value, obtain the projectile images in the two line array cameras when the multiple projectiles pass through the space domain light curtain and the time information of the multiple projectiles passing through the space domain light curtain; Step 3: Obtain the number of projectile shadows at the same time in the projectile image, and calculate the target coordinates of the projectile using different methods according to the number of shadows at the same time: When the number of shadows on the image at the same time is less than or equal to 1, multiple projectiles successively pass through the airspace light curtain, and the target coordinates of the projectiles are calculated using a dual-line array camera intersection measurement method; When the number of shadows on the image at the same time is greater than 1, multiple projectiles pass through the spatial light curtain at the same time. The moment information of the multiple projectiles passing through the spatial light curtain and the moment information of the temporal light curtain are used to calculate the target coordinates of each projectile and identify the multiple projectiles.

2. The time / space domain combined light curtain projectile identification method for high-speed rotary gun density test according to claim 1 is characterized in that: In step 3, the steps of using the dual-line array camera intersection to measure the projectile target coordinates are as follows: Step (1): Obtain the structural parameters of the dual-line array camera, such as the camera horizontal angle, pixel spacing, and lens focal length; Step (2): Read the projectile images in the two linear array cameras when the multiple projectiles pass through the airspace light curtain, and extract the central pixel number of each projectile in the image; Step (3): Substitute the structural parameters of the linear array camera and the central pixel number of the projectile image into the double linear array camera intersection target coordinate measurement formula to calculate the target coordinate of each projectile.

3. The time / space domain combined light curtain projectile identification method for high-speed rotary gun density test according to claim 1 is characterized in that: In step 3, the steps of identifying multiple projectiles are as follows: Step (1): obtaining the structural parameters of the time domain light curtain, including the angles of six detection light curtains and the distances between the intersection points of the light curtains; Step (2): obtaining the time value of multiple projectiles passing through the time domain light curtain and the time value obtained from the projectile image in the space domain light curtain; Step (3): according to the time value when the projectile passes through the six detection light curtains and one spatial light curtain of the time domain light curtain, combined with the plane equations of the seven light curtains, establish the projectile trajectory straight line equation; Step (4): Arrange and combine the time values ​​of the projectile passing through the six detection light curtains and one spatial light curtain in the time domain light curtain to obtain all possible passing time sequences of multiple projectiles passing through the seven light curtains; Step (5): Substituting the transition moment sequence into the trajectory straight line equation, and calculating the trajectory straight line corresponding to each moment sequence; Step (6): According to the positional relationship of the two spatial straight lines being parallel or overlapping, the sequence of the passing moments of the projectiles is matched, the false target coordinates in the spatial light curtain are eliminated, and multiple projectiles are identified.

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