Laser target calibration and target scoring calculation method

Abstract

The invention discloses a laser target calibration and target scoring calculation method, and belongs to the technical field of calibration measurement. According to the method, representative and uniformly distributed standard points are selected through the coordinate calibration step, and the data of the standard points are filled by using linear interpolation and cubic spline interpolation algorithms, so that a coordinate mapping relation between a distorted target plate picture and a normal target plate picture is successfully constructed; the problem of image barrel distortion caused by a fisheye lens is effectively solved, subsequent target scoring calculation can be carried out based on accurate coordinate information, in the target scoring calculation link, according to the established coordinate mapping relation, the corresponding coordinates of the hit point on the distorted target plate picture in the normal target plate picture can be accurately calculated, and the target scoring accuracy is improved. The Euclidean distance between the coordinate and the target center coordinate is calculated, the number of shooting rings is obtained by combining the width of a single ring, and the accuracy and stability of calibration and target scoring calculation are further ensured through a discrete point processing method obtained through detailed analysis of the imaging law of the fisheye lens.

Description

Technical Field

[0001] The invention belongs to the technical field of calibration and measurement, and in particular relates to a laser target calibration and target reporting calculation method. Background Art

[0002] In the process of continuous development and evolution of shooting technology, accurate target calibration and target reporting calculation have always been one of the core concerns. Early target reporting methods mostly relied on manual observation and measurement. This traditional model is extremely inefficient and prone to errors due to interference from human subjective factors. It is difficult to adapt to the strict requirements of modern large-scale, high-intensity shooting training and high-standard competitions for accuracy and efficiency.

[0003] With the advancement of science and technology, laser target systems have gradually emerged and become an important technical means in the field of shooting. Laser targets detect the location of the impact point by emitting laser beams and receiving reflected signals, which has the advantages of being fast and highly automated. However, its imaging process, especially when using fisheye lenses to obtain target images, has encountered an extremely difficult problem. The fisheye lens has an ultra-wide viewing angle of nearly 180 degrees, which enables it to capture a complete target image in a small target box space, but at the same time, it inevitably produces severe barrel distortion.

[0004] This barrel distortion causes the target image to deform significantly, and the originally regular target shape and target ring layout are severely distorted. The straight lines on the target become curves in the image, and the circular target ring no longer remains a perfect circle, but bulges outward in a barrel shape. This phenomenon directly leads to the disorder of the coordinate system in the image. When performing laser target calibration and target reporting calculations, there is a large deviation between the coordinates of the hit point obtained based on the distorted image and the actual position on the actual target. If these distorted coordinate data are used directly for target reporting calculations, the determination result of the number of shooting rings will seriously deviate from the actual situation and cannot accurately reflect the actual shooting level of the shooter. Summary of the invention

[0005] In view of the above situation, in order to overcome the defects of the prior art, the present invention develops a more accurate and efficient calibration and target calculation method specifically for the characteristics of the fisheye lens to fill this technical gap.

[0006] In order to achieve the above object, the following technical solution is adopted: The present invention provides a laser target calibration and target reporting calculation method, comprising the following steps:

[0007] S1. Image acquisition: Use a fisheye lens with an ultra-wide viewing angle of nearly 180 degrees to shoot the target plate in a narrow target box space to obtain a complete distorted target plate image;

[0008] S2. Coordinate calibration: Select representative and evenly distributed standard points, manually determine the coordinates of the standard points on the distorted target image, use linear interpolation and cubic spline interpolation algorithms to fill in the standard point data, and build a coordinate mapping relationship between the points on the distorted target image and the normal target image;

[0009] S3. Target reporting calculation: After the shooting occurs, first determine the coordinates of the hitting point on the distorted target board image, and then calculate the corresponding coordinates of the hitting point coordinates in the normal target board image based on the previously established coordinate mapping relationship. After obtaining the hitting point coordinates in the normal target board image, calculate the Euclidean distance between this coordinate and the bull's eye coordinate, divide the calculated distance from the bull's eye by the width of a single ring, and the result is the number of shooting rings.

[0010] Furthermore, the problem of severe barrel distortion of the target plate image obtained by the fisheye lens is solved by the following method:

[0011] S201, adjust the structure so that the optical center of the camera is aligned with the center of the concentric circles of the target plate, and obtain the distortion map, where point O is the center of the concentric circles, L(O, P 1 , P 2 , P 3 , P 4 , P 5 ) represents the intersection point P of a radius and each circle 1 , P 2 , P 3 , P 4 and P 5 , OP 1 >P 1 P 2 >P 2 P 3 >P 3 P 4 >P 4 P 5 , that is, as the distance between the line segment representing the width of a single ring and the center of the circle increases, the length of the line segment representing the width of a single ring shows a monotonically decreasing trend. In the original image corresponding to the distortion image, OP 1 =P 1 P 2 =P 2 P 3 =P 3 P 4 =P 4 P 5 , that is, all single ring widths are equal;

[0012] S202, take D 0 =0,D 1 =OP 1 ,D 2 =OP 2,D 3 =OP 3 ,D 4 =OP 4 ,D 5 =OP 5 D 0 Denotes the origin of coordinates, D 1 To D 5 These five values ​​represent P 1 To P 5 The distance from these five points to the center of the circle is 1, and the width of the single ring is D 0 To D 5 The X coordinate values ​​of these 6 points are D 0 To D 5 The value of the Y coordinate is D on the original image. 0 To D 5 As the distance between the point on the original image and the center of the circle increases, the increase in the distance between the corresponding point on the distortion image and the center of the circle decreases;

[0013] S203, using the known discrete points in the discrete point graph, a continuous curve S(x) is obtained, wherein the parameter x of the curve is the distance between the point on the distortion graph and the center of the circle, and the value is the distance between the corresponding point on the original image and the center of the circle.

[0014] Furthermore, the distance between the corresponding point on the original image and the center of the circle satisfies the following conditions:

[0015] (1) All discrete points need to fall on S(x);

[0016] (2) In the integer interval, the change of S(x) satisfies the imaging law of the fisheye lens;

[0017] (3) The curve before and after the discrete point should remain smooth.

[0018] Furthermore, the mathematical analysis and specific calculation process related to the cubic spline interpolation are as follows:

[0019] S401, suppose there is a set of data points (x 0 ,y 0 ), (x 1 ,y 1 ),...,(x n ,y n ), we hope to find a function S(x) for interpolation so that S(x i )=y i , cubic spline interpolation satisfies these interpolation conditions by constructing a cubic polynomial on each segment, and further requires that the derivative and second-order derivative of the curve at each data point are also equal, so as to achieve smoothness;

[0020] S402, for each segment [x i, x i+1 ], construct a cubic polynomial:

[0021] S i (x) = a i +b i (xx i )+c i (xx i ) 2 +d i (xx i ) 3 ,

[0022] where a i 、b i 、c i and d i is the coefficient to be determined,

[0023] In order to ensure the smoothness of the overall curve, cubic spline interpolation sets the following conditions for the polynomial coefficients of each segment:

[0024] Interpolation condition: At each data point x i At the point, the curve value satisfies S(x i )=y i ,

[0025] First-order derivative continuity: At each adjacent data point, the first-order derivative of the curve is equal, that is, S i ′(x i+1 )=S i+1 ′(x i+1 );

[0026] Second-order derivative continuity: At each adjacent data point, the second-order derivative of the curve is also equal, that is, S i ″(x i+1 )=S i+1 ″(x i+1 );

[0027] Boundary conditions: Use natural boundary conditions, that is, the second-order derivative of the curve at the endpoint is zero;

[0028] S403, establish a system of equations to solve all the segmented polynomial coefficients, from the interpolation condition S i (x i )=y i and S i (x i+1 )=y i+1 You can get:

[0029] a i =y i ,

[0030] Calculate the distance between each adjacent data point: h i =x i+1 -x i ,

[0031] S404. Through the continuity condition of the second-order derivative, establish the second-order derivative c i The tridiagonal equations of i =x i+1 -x i , represents the distance between adjacent nodes,

[0032] Auxiliary amount α i , used to represent the spline curve at point x i and x i+1 The difference in slope at :

[0033]

[0034] According to the continuity condition of the second-order derivative, we get a i This can be expressed as a tridiagonal matrix equation:

[0035] For i=1,...,n-2, the equation is:

[0036] h i-1 c i-1 +2(h i-1 +h i )c i +h i c i+1 =α i ,

[0037] This equation describes an n-2 order tridiagonal linear system, which can be expressed in the following matrix form:

[0038]

[0039] In this matrix, the main diagonal elements are 2(h i-1 +h i ),

[0040] The lower and upper diagonal elements are h i-1 and h i .

[0041] Furthermore, a special algorithm for tridiagonal matrices is used to chase the matrix equations to solve c i The steps of the catch-up method are as follows:

[0042] S501, forward elimination: successively transform the matrix into upper triangular form, and gradually eliminate the lower triangular elements;

[0043] S502, back-substitution: Start back-substitution from the last row and find c in sequence n-2 , c n-3 , ..., c 1 The value of

[0044] By obtaining c i value, you can continue to solve other coefficients b i and d i :

[0045]

[0046] S503, determine all coefficients a, b, c, d, given any interpolation point xi, find the interval it belongs to and calculate the corresponding function value.

[0047] Furthermore, the discrete point D is solved by the following method 1 To D 5 The value problem of :

[0048] S601, introduced 8 groups of calibration points, each group has 5 points, starting from point 0, in the clockwise direction, draw a radius every 45 degrees, denoted as L i , each radius has 5 intersection points with the concentric circles, these 5 points are L i Group calibration points, L i The polar coordinate angle corresponding to the point on is θ i , where i = 1, 2, 3, 4, 5, 6, 7, 8, so 8 lines are drawn and 8 groups of 40 calibration points are obtained;

[0049] S602: Calculate the distance between each set of calibration points and the center O, for example, L 3 (P 31 , P 32 , P 33 , P 34 , P 35 ) This set of calibration points, where D 31 , D 32 , D 33 , D 34 , D 35 These five values ​​represent the distances from the five points to the center of the circle, θ 3 For L 3 Polar coordinate angles, this set of calibration points is called L 3 (P 31 , P 32 , P 33 , P 34 , P 35 ,θ 3 );

[0050] S603. For the red point to be estimated, the polar coordinate angle θ corresponding to Q can be calculated, so as to determine between which two lines Q falls.

[0051] Furthermore, the following linear interpolation algorithm is used to obtain the true distance between the target point Q and the center of the circle:

[0052]

[0053] D i =D 3i (1-ratio)+D 4i ratio,i=1,2,3,4,5,

[0054] Among them, ratio represents the ratio of θ to θ 4 The distance θ 4 With θ 3 The ratio of the distance, that is, the interpolation result is affected by L 3 and L 4 The proportion of the impact, the final D i The five values ​​in represent the distance from the intersection of the radius of Q and the five rings to the center of the circle. i The actual distance between the target point Q and the center of the circle can be obtained by performing cubic spline interpolation on the values ​​in .

[0055] Furthermore, the theoretical number of rings hitting the center of the circle is 11.0. The farther away from the center of the circle, the smaller the number of rings reported. The calculation formula for the number of rings reported is:

[0056]

[0057] The beneficial effects of the present invention are as follows: the present invention selects representative and evenly distributed standard points through a coordinate calibration step, and uses linear interpolation and cubic spline interpolation algorithms to fill in the standard point data, successfully constructs a coordinate mapping relationship between a distorted target plate image and a normal target plate image, effectively solves the image barrel distortion problem caused by a fisheye lens, and enables subsequent target reporting calculations to be performed based on accurate coordinate information. Secondly, in the target reporting calculation link, according to the established coordinate mapping relationship, the corresponding coordinates of the hit point on the distorted target plate image in the normal target plate image can be accurately calculated, and then the Euclidean distance between the coordinates and the bull's eye coordinates is calculated, and the number of shooting rings is obtained in combination with the single ring width. The whole process is scientific and reasonable, and the calculation is accurate. The discrete point processing method obtained by detailed analysis of the imaging law of the fisheye lens, the rigorous mathematical analysis and calculation process related to the cubic spline interpolation, and the special pursuit method for solving the coefficients, further ensure the accuracy and stability of the calibration and target reporting calculations, and can provide a reliable basis for performance judgment for shooting training, competitions, etc., which is helpful to improve the accuracy and practicality of the application of laser target technology in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a comparison between the barrel distorted image and the normal image obtained by the fisheye lens;

[0059] Figure 2 Schematic diagram of the imaging principle of the fisheye lens;

[0060] Figure 3 Imaging effect diagram for adjusting the structure so that the optical center of the camera is aligned with the center of the concentric circle of the target plate;

[0061] Figure 4 is an image without distortion;

[0062] Figure 5 It is the relationship diagram between the intersection point of the ring and the distance between the center of the circle on the original image and the distorted image;

[0063] Figure 6 is the image of the continuous curve S(x);

[0064] Figure 7 Schematic diagram for introducing calibration points.

[0065] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0067] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0068] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0069] The following is combined with Figure 1-7 , an embodiment provided by the present invention is explained.

[0070] Example

[0071] The target box uses a fisheye lens to take pictures of the target plate, and the target plate image obtained will produce a relatively serious barrel distortion. Barrel distortion refers to the outward expansion of the picture, especially the straight lines in the edge area will appear as outward curved lines, and the entire picture will spread outward from the center, giving people a "bulging" visual effect, such as Figure 1 shown.

[0072] This phenomenon is related to the imaging principle of the fisheye lens. The fisheye camera will compress the incident light at the edge, resulting in serious distortion of the image, such as Figure 2 As shown in the figure, on the fisheye image plane, the closer to the point corresponding to the optical axis on the fisheye image plane (this point is called the optical center), the smaller the degree of distortion. In the imaging results of a qualified fisheye camera, it can be considered that the degree of distortion of all points with the same distance from the optical center is the same, and the farther away from the optical center, the more serious the distortion.

[0073] Therefore, the present invention provides a laser target calibration and target reporting calculation method, comprising the following steps:

[0074] S1. Image acquisition: Use a fisheye lens with an ultra-wide viewing angle of nearly 180 degrees to shoot the target plate in a narrow target box space to obtain a complete distorted target plate image;

[0075] S2. Coordinate calibration: Select representative and evenly distributed standard points, manually determine the coordinates of the standard points on the distorted target image, use linear interpolation and cubic spline interpolation algorithms to fill in the standard point data, and build a coordinate mapping relationship between the points on the distorted target image and the normal target image;

[0076] S3. Target reporting calculation: After the shooting occurs, first determine the coordinates of the hitting point on the distorted target board image, and then calculate the corresponding coordinates of the hitting point coordinates in the normal target board image based on the previously established coordinate mapping relationship. After obtaining the hitting point coordinates in the normal target board image, calculate the Euclidean distance between this coordinate and the bull's eye coordinate, divide the calculated distance from the bull's eye by the width of a single ring, and the result is the number of shooting rings.

[0077] Specifically, the following methods are used to solve the problem that the target plate image obtained by the fisheye lens will produce severe barrel distortion:

[0078] S201, adjust the structure so that the optical center of the camera is aligned with the center of the concentric circle of the target plate, and obtain the distortion map. The imaging effect is as follows Figure 3 As shown, point O is the center of the concentric circles, L(O, P 1 , P 2 , P 3 , P 4 , P 5 ) represents the intersection point P of a radius and each circle 1 , P2 , P 3 , P 4 and P 5 , OP 1 >P 1 P 2 >P 2 P 3 >P 3 P 4 >P 4 P 5 , that is, as the distance between the line segment representing the width of a single ring and the center of the circle increases, the length of the line segment representing the width of a single ring shows a monotonically decreasing trend, which is consistent with the distortion diagram Figure 3 The corresponding undistorted image is Figure 4 , called the original image, in the original image OP 1 =P 1 P 2 =P 2 P 3 =P 3 P 4 =P 4 P 5 , that is, all single ring widths are equal;

[0079] S202, take D 0 =0,D 1 =OP 1 ,D 2 =OP 2 ,D 3 =OP 3 ,D 4 =OP 4 ,D 5 =OP 5 , D 0 Denotes the origin of coordinates, D 1 To D 5 These five values ​​represent P 1 To P 5 The distance from these five points to the center of the circle is 1, and the width of the single ring is D 0 To D 5 The X coordinate values ​​of these 6 points are D 0 To D 5 The value of the Y coordinate is D on the original image. 0 To D 5 value, Figure 5 The relationship between the distance between the intersection point of the circle and the center of the circle on the original image and the distorted image is shown in Figure 1. That is, as the distance between the point on the original image and the center of the circle increases, the increase in the distance between the corresponding point on the distorted image and the center of the circle decreases;

[0080] S203, through Figure 5 For the known discrete points in the discrete point graph, find Figure 6 The continuous curve S(x) shown in , the parameter x of the curve is the distance between the point on the distortion image and the center of the circle, and the value is the distance between the corresponding point on the original image and the center of the circle.

[0081] The distance between the corresponding point on the original image and the center of the circle satisfies the following conditions:

[0082] (1) All discrete points need to fall on S(x);

[0083] (2) In the integer interval, the change of S(x) satisfies the imaging law of the fisheye lens;

[0084] (3) The curve before and after the discrete point should remain smooth.

[0085] The mathematical analysis and specific calculation process related to the cubic spline interpolation are as follows:

[0086] S401, suppose there is a set of data points (x 0 ,y 0 ), (x 1 ,y 1 ),...,(x n ,y n ), we hope to find a function S(x) for interpolation so that S(x i )=y i , cubic spline interpolation satisfies these interpolation conditions by constructing a cubic polynomial on each segment, and further requires that the derivative and second-order derivative of the curve at each data point are also equal, so as to achieve smoothness;

[0087] S402, for each segment [x i , x i+1 ], construct a cubic polynomial:

[0088] S i (x) = a i +b i (xx i )+c i (xx i ) 2 +d i (xx i ) 3 ,

[0089] where a i 、b i 、c i and d i is the coefficient to be determined,

[0090] In order to ensure the smoothness of the overall curve, cubic spline interpolation sets the following conditions for the polynomial coefficients of each segment:

[0091] Interpolation condition: At each data point x i At the point, the curve value satisfies S(x i )=y i ,

[0092] First-order derivative continuity: At each adjacent data point, the first-order derivative of the curve is equal, that is, S i ′(x i+1 )=S i+1 ′(x i+1 );

[0093] Second-order derivative continuity: At each adjacent data point, the second-order derivative of the curve is also equal, that is, S i ″(x i+1 )=S i+1 ″(x i+1 );

[0094] Boundary conditions: Use natural boundary conditions, that is, the second-order derivative of the curve at the endpoint is zero;

[0095] S403, establish a system of equations to solve all the segmented polynomial coefficients, from the interpolation condition S i (x i )=y i and S i (x i+1 )=y i+1 You can get:

[0096] a i =y i ,

[0097] Calculate the distance between each adjacent data point: h i =x i+1 -x i ,

[0098] S404. Through the continuity condition of the second-order derivative, establish the second-order derivative c i The tridiagonal equations of i =x i+1 -x i , represents the distance between adjacent nodes,

[0099] Auxiliary amount α i , used to represent the spline curve at point x i and x i+1 The difference in slope at :

[0100]

[0101] According to the continuity condition of the second-order derivative, we get a i This can be expressed as a tridiagonal matrix equation:

[0102] For i=1,...,n-2, the equation is:

[0103] h i-1 c i-1 +2(h i-1 +h i )c i +h i c i+1 =α i ,

[0104] This equation describes an n-2 order tridiagonal linear system, which can be expressed in the following matrix form:

[0105]

[0106] In this matrix, the main diagonal elements are 2(h i-1 +h i ),

[0107] The lower and upper diagonal elements are h i-1 and h i .

[0108] The tridiagonal matrix is ​​used to solve the matrix equation for c i The steps of the catch-up method are as follows:

[0109] S501, forward elimination: successively transform the matrix into upper triangular form, and gradually eliminate the lower triangular elements;

[0110] S502, back-substitution: Start back-substitution from the last row and find c in sequence n-2 , c n-3 , ..., c 1 The value of

[0111] By obtaining c i value, you can continue to solve other coefficients b i and d i :

[0112]

[0113] S503, determine all coefficients a, b, c, d, given any interpolation point xi, find the interval it belongs to and calculate the corresponding function value.

[0114] The discrete point D is solved by the following method 1 To D 5 The value problem of :

[0115] S601, introduced 8 groups of calibration points, each group has 5 points, such as Figure 7As shown by the small white dot in the figure, starting from point 0, draw a radius every 45 degrees in the clockwise direction, denoted as L i , each radius has 5 intersection points with the concentric circles, these 5 points are L i Group calibration points, L i The polar coordinate angle corresponding to the point on is θ i , where i = 1, 2, 3, 4, 5, 6, 7, 8. This way, 8 lines are drawn and 8 groups of 40 calibration points are obtained;

[0116] S602: Calculate the distance between each set of calibration points and the center O, for example, L 3 (P 31 , P 32 , P 33 , P 34 , P 35 ) This set of calibration points, where D 31 , D 32 , D 33 , D 34 , D 35 These five values ​​represent the distances from the five points to the center of the circle, θ 3 For L 3 Polar coordinate angles, this set of calibration points is called L 3 (P 31 , P 32 , P 33 , P 34 , P 35 ,θ 3 );

[0117] S603. For the red point to be estimated, the polar coordinate angle θ corresponding to Q can be calculated, so as to determine between which two lines Q falls.

[0118] Use the following linear interpolation algorithm to get the actual distance between the target point Q and the center of the circle:

[0119]

[0120] D i =D 3i (1-ratio)+D 4i ratio,i=1,2,3,4,5,

[0121] Among them, ratio represents the ratio of θ to θ 4 The distance θ 4 With θ 3 The ratio of the distance, that is, the interpolation result is affected by L 3 and L 4 The proportion of the impact, the final D iThe five values ​​in represent the distance from the intersection of the radius of Q and the five rings to the center of the circle. i The actual distance between the target point Q and the center of the circle can be obtained by performing cubic spline interpolation on the values ​​in .

[0122] The theoretical number of rings for hitting the center of the circle is 11.0. The farther away from the center of the circle, the smaller the number of rings reported. The calculation formula for the number of rings reported is:

[0123]

[0124] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0125] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A laser target calibration and target reporting calculation method, characterized in that: The following steps are involved: S1. Image acquisition: Use a fisheye lens with an ultra-wide viewing angle of nearly 180 degrees to shoot the target plate in a narrow target box space to obtain a complete distorted target plate image; S2. Coordinate calibration: Select representative and evenly distributed standard points, manually determine the coordinates of the standard points on the distorted target image, use linear interpolation and cubic spline interpolation algorithms to fill in the standard point data, and build a coordinate mapping relationship between the points on the distorted target image and the normal target image; S3, target reporting calculation: after the shooting occurs, first determine the coordinates of the hit point on the distorted target board image, then calculate the corresponding coordinates of the hit point coordinates in the normal target board image based on the previously established coordinate mapping relationship, after obtaining the hit point coordinates in the normal target board image, calculate the Euclidean distance between this coordinate and the bull's eye coordinate, divide the calculated distance from the bull's eye by the width of a single ring, and the result is the number of shooting rings; The following methods are used to solve the problem of severe barrel distortion of the target plate image obtained by the fisheye lens: s201. Adjust the structure so that the optical center of the camera is aligned with the center of the concentric circles of the target plate to obtain a distortion map. Point O is the center of the concentric circles. L(O, P1, P2, P3, P4, P5) represents the intersection of a radius with each circle P1, P2, P3, P4 and P5. OP1>P1P2>P2P3>P3P4>P4P5, that is, as the distance between the line segment representing the width of a single ring and the center of the circle increases, the length of the line segment representing the width of a single ring shows a monotonically decreasing trend. In the original image corresponding to the distortion map, OP1=P1P2=P2P3=P3P4=P4P5, that is, the widths of all single rings are equal. S202, set D0=0, D1=OP1, D2=OP2, D3=OP3, D4=OP4, D5=OP5, D0 represents the origin of the coordinates, the five values ​​of D1 to D5 represent the distances from the five points P1 to P5 to the center of the circle respectively, the width of the single ring is set to 1, the x-coordinate values ​​of the six points D0 to D5 are the values ​​of D0 to D5 on the distortion map, and the y-coordinate values ​​are the values ​​of D0 to D5 on the original image. As the distance between the point on the original image and the center of the circle increases, the increase in the distance between the corresponding point on the distortion map and the center of the circle decreases continuously; S203, using the known discrete points in the discrete point graph, a continuous curve S(x) is obtained, wherein the parameter x of the curve is the distance between the point on the distortion graph and the center of the circle, and the value is the distance between the corresponding point on the original image and the center of the circle.

2. The laser target calibration and target reporting calculation method according to claim 1, characterized in that: The distance between the corresponding point on the original image and the center of the circle satisfies the following conditions: (1) All discrete points need to fall on S(x); (2) In the integer interval, the change of S(x) satisfies the imaging law of the fisheye lens; (3) The curve before and after the discrete point should remain smooth.

3. The laser target calibration and target reporting calculation method according to claim 2 is characterized in that: The mathematical analysis and specific calculation process related to the cubic spline interpolation are as follows: S401. Assume that there is a set of data points (x0, y0), (x1, y1), ..., (x n ,y n ), we hope to find a function S(x) for interpolation so that S(x i )=y i , cubic spline interpolation satisfies these interpolation conditions by constructing a cubic polynomial on each segment, and further requires that the derivative and second-order derivative of the curve at each data point are also equal, so as to achieve smoothness; S402, for each segment [x i , x i+1 ], construct a cubic polynomial: S i (x)=a i +b i (x-x i )+c i (x-x i ) 2 +d i (x-x i ) 3 , where a i 、b i 、c i and d i is the coefficient to be determined, In order to ensure the smoothness of the overall curve, cubic spline interpolation sets the following conditions for the polynomial coefficients of each segment: Interpolation condition: At each data point x i At the point, the curve value satisfies S(x i )=y i , First-order derivative continuity: At each adjacent data point, the first-order derivative of the curve is equal, that is, S i ′(x i+1 )=S i+1 ′(x i+1 ); Second-order derivative continuity: At each adjacent data point, the second-order derivative of the curve is also equal, that is, S i ″(x i+1 )=S i+1 ″(x i+1 ); Boundary conditions: Use natural boundary conditions, that is, the second-order derivative of the curve at the endpoint is zero; S403, establish a system of equations to solve all the segmented polynomial coefficients, from the interpolation condition S i (x i )=y i and S i (x i+1 )=y i+1 You can get: to i =and i , Calculate the distance between each adjacent data point: h i =x i+1 -x i , S404. Through the continuity condition of the second-order derivative, establish the second-order derivative c i The tridiagonal equations of i =x i+1 -x i , represents the distance between adjacent nodes, Auxiliary amount α i , used to represent the spline curve at point x i and x i+1 The difference in slope at : According to the continuity condition of the second-order derivative, we get a i This can be expressed as a tridiagonal matrix equation: For i=1,...,n-2, the equation is: h i-1 C i-1 +2(h i-1 +h i )c i +h i c i+1 =α i , This equation describes an n-2 order tridiagonal linear system, which can be expressed in the following matrix form: In this matrix, the main diagonal elements are 2(h i-1 +h i , The lower and upper diagonal elements are h i-1 and h i .

4. The laser target calibration and target reporting calculation method according to claim 3 is characterized in that: The tridiagonal matrix is ​​used to solve the matrix equation for c i The steps of the catch-up method are as follows: S501, forward elimination: successively transform the matrix into upper triangular form, and gradually eliminate the lower triangular elements; S502, back-substitution: Start back-substitution from the last row and find c in sequence n-2 , c n-3 , ..., the value of c1, By obtaining c i value, you can continue to solve other coefficients b i and d i : S503, determine all coefficients a, b, c, d, given any interpolation point xi, find the interval it belongs to and calculate the corresponding function value.

5. The laser target calibration and target reporting calculation method according to claim 4 is characterized in that: The problem of determining the values ​​of discrete points D1 to D5 is solved by the following method: S601, introduced 8 groups of calibration points, each group has 5 points, starting from point 0, in the clockwise direction, draw a radius every 45 degrees, denoted as L i , each radius has 5 intersection points with the concentric circles, these 5 points are L i Group calibration points, L i The polar coordinate angle corresponding to the point on is θ i , where i = 1, 2, 3, 4, 5, 6, 7, 8, so 8 lines are drawn and 8 groups of 40 calibration points are obtained; S602, calculate the distance between each set of calibration points and the center O, for example, L3(P 31 , P 32 , P 33 , P 34 , P 35 ) This set of calibration points, where D 31 , D 32 , D 33 , D 34 , D 35 These five values ​​represent the distances from the five points to the center of the circle. θ3 is the polar coordinate angle of L3. This set of calibration points is called L3(P 31 , P 32 , P 33 , P 34 , P 35 ,θ3); S603. For the red point to be estimated, the polar coordinate angle θ corresponding to Q can be calculated, so as to determine between which two lines Q falls.

6. The laser target calibration and target reporting calculation method according to claim 5 is characterized in that: Use the following linear interpolation algorithm to get the actual distance between the target point Q and the center of the circle: D i =D 3i ·(1-ratio)+D 4i ·ratio,i=1,2,3,4,5, Among them, ratio represents the ratio of the distance between θ and θ4 to the distance between θ4 and θ3, that is, the ratio of the interpolation result affected by L3 and L4. The final D i The five values ​​in represent the distance from the intersection of the radius of Q and the five rings to the center of the circle. i The actual distance between the target point Q and the center of the circle can be obtained by performing cubic spline interpolation on the values ​​in .

7. The laser target calibration and target reporting calculation method according to claim 6 is characterized in that: The theoretical number of rings for hitting the center of the circle is 11.

0. The farther away from the center of the circle, the smaller the number of rings reported. The calculation formula for the number of rings reported is:

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