A method for establishing the mapping relationship between space straight line vector and projection plane posture

Abstract

The present invention provides a method for establishing a mapping relationship between a space straight line vector and a projection plane posture, which belongs to the field of conventional shooting range optical posture measurement and is used to standardize the vector relationship of a straight line vector from space to a plane projection. The present invention uses two approaches to posture solution, namely vector rotation and intersection reconstruction, to achieve the mapping of a space straight line vector to a projection image plane and the verification of the method results; the method proposed by the present invention is used to achieve the posture mapping based on the straight line vector space to the plane for the first time; the technical method in the present invention can be used as the basic basis for posture processing of targets with straight line features, and is widely used in the field of military camera measurement posture testing.

Description

Technical Field

[0001] The invention relates to the field of conventional weapon testing, and in particular to the field of shooting range optical posture measurement. Background Art

[0002] Linear vectors are very advantageous in optical attitude measurement. At present, optical attitude processing methods are mainly based on three features, namely, based on multiple (more than 3) corner points of the same name, based on target models, and based on linear vector features. For the target measurement target in the shooting range, there are very few corner points of the same name that can be extracted from multiple perspectives without occlusion and visible during the dynamic flight of the target, so the method based on multi-point measurement is not very applicable; when the measured shape cannot be accurately obtained, the model matching method loses the calculation premise. In addition, the model matching method has a large amount of calculation, is time-consuming, and has low efficiency; the method based on the intersection of linear vectors not only does not require the same name matching, but is also more flexible in feature extraction, and only requires the substation vectors to be parallel.

[0003] There are basic collinear equations when calculating trajectory in video measurement. However, there is no mature relationship model for mapping spatial linear vectors to projection plane posture based on the intersection of linear vectors. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a method for establishing the mapping relationship between a spatial straight line vector and a projection plane posture. The mapping of a spatial straight line vector to a projection image plane and the verification of the method results are realized by utilizing two approaches to posture solution (vector rotation and intersection reconstruction), which can improve the intuitiveness and convenience of posture calculation by intersection of straight line vectors.

[0005] The technical solution adopted by the present invention to solve the technical problem comprises the following steps:

[0006] (1) Normalized vector L0(abc) of the space line vector in the target coordinate system under the initial zero attitude condition T , through the yaw angle Ψ, pitch angle After the roll angle γ is rotated, the vector L(lmn) of the space straight line vector in the reference coordinate system at the calculation time is obtained. T ;

[0007] (2) The vector L(lmn) T From the reference coordinate system, the camera optical axis is pointed to (A, E) and then transformed to the camera coordinate system, and L is obtained. C (X C Y C Z C ) T ;

[0008] (3) L C (X C YC Z C ) T Convert to image plane coordinate system l p (yz) T ,

[0009] (4) Obtain the angle α of the spatial straight line vector on the projection image plane,

[0010] The rotation matrix in step (1) is

[0011] In the step (2), L C =R(-E)R(-A)L, where

[0012] The step (4) obtains the two substation projection image plane angles α1 and α2, and uses the central axis intersection method to realize the spatial straight line vector reconstruction. The reconstruction result is L′(l′m′n′) T , compare the consistency of L′ and L, that is, verify the correctness of the mapping relationship between the space straight line vector and the projection plane posture.

[0013] The beneficial effects of the present invention are: for the first time, the mapping relationship from the space straight line vector to the projection image plane posture is established, and the space straight line vector is reconstructed through the substation mapping results to achieve the purpose of closed-loop verification of the correctness of the mapping results. The present invention provides an important 3D-2D posture mapping relationship for optical posture processing based on straight line vectors, and unifies the processing path for posture processing based on straight line vectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The present invention includes but is not limited to the following embodiments.

[0016] The technical problem to be solved by the present invention is to establish the posture mapping relationship from the spatial straight line vector to the projection plane, that is, to determine the angle α of the spatial straight line vector on the projection image plane, and to use the mapping results of two substations to reconstruct the spatial straight line vector through the conventional central axis intersection method to verify the correctness of the mapping result, thereby providing an important theoretical basis for the intersection method based on the straight line vector.

[0017] Obtaining the mapping relationship between the space straight line vector and the plane posture includes the following steps:

[0018] Step 1: Normalized vector L0(abc) of the space straight line vector in the target coordinate system under the initial zero attitude condition T , through the yaw angle Ψ, pitch angle Roll angle γ rotation (rotation matrix is After that, obtain the vector L(lmn) of the space straight line vector in the reference coordinate system at the calculation time T ;

[0019]

[0020] in:

[0021]

[0022]

[0023]

[0024] All the coordinate systems involved are based on the coordinate systems involved in the conventional posture processing algorithm. The target coordinate system takes the target center axis as the X T Axis, head is positive; the reference coordinate system takes north as X axis; the camera coordinate system takes the optical axis as X axis C Axis, parallel to the image plane and upward is Y C Axis; the image plane coordinate system y and Z axes are parallel to the camera coordinate system Y C Axis, Z C Axis. The initial zero pose means that the target coordinate system is parallel to the reference coordinate system.

[0025] Step 2: Transform the vector L(lmn) T From the reference coordinate system, the camera optical axis is pointed to (A, E) and then transformed to the camera coordinate system, and L is obtained. C (X C Y C Z C ) T ;

[0026] L C =R(-E)R(-A)L

[0027] in:

[0028]

[0029]

[0030] Step 3: Transform the space straight line vector from the camera coordinate system L C (X C Y C Z C ) T Convert to image plane coordinate system lp (yz) T ;

[0031]

[0032] Step 4: Obtain the angle α of the spatial straight line vector on the projection image plane (the angle from the image plane z-axis to the normal line of the image plane straight line vector).

[0033]

[0034] The present invention verifies the correctness of the result of the spatial straight line vector to the projection plane posture mapping. The verification method is as follows: after the spatial straight line vector to the projection plane posture mapping is realized by the above method, the projection image plane angles α1 and α2 of the two substations are obtained, and the spatial straight line vector is reconstructed by the conventional central axis intersection method. The reconstruction result is L′(l′m′n′) T By comparing the consistency of L′ and L, the correctness of the mapping relationship from the space straight line vector to the projection plane posture can be verified.

[0035] Take the target center axis vector L0(1 0 0) T Take the example to illustrate the substation site, target trajectory and attitude angle The settings (roll does not affect the center axis) are shown in Table 1;

[0036] Table 1. Substation sites, target trajectories and attitude angles set up

[0037]

[0038] The mapping of the medial axis vector to the projection image plane vector includes the following steps:

[0039] Step 1: Normalized vector L0(1 0 0) of the space line vector in the target coordinate system under the initial zero attitude condition T , through the yaw angle Ψ, pitch angle Rotation (the rotation matrix is ), then obtain the vector L(lmn) of the space straight line vector in the reference coordinate system at the calculation time T ;

[0040]

[0041] have to:

[0042]

[0043] Step 2: Transform the vector L(lmn) T From the reference coordinate system through the camera optical axis (A 1,2 ,E 1,2) is converted to the camera coordinate system of substations (1, 2), and L C1,2 (X C1,2 Y C1,2 Z C1,2 ) T , where the substation (A 1,2 ,E 1,2 ) angle is obtained from the target trajectory relative to the station position;

[0044] L C =R(-E)R(-A)L

[0045] have to:

[0046]

[0047] Step 3: Transform the space straight line vector from the camera coordinate system L C (X C Y C Z C ) T Convert to image plane coordinate system l p (yz) T ;

[0048]

[0049] have to:

[0050]

[0051] Step 4: Obtain the angles α1 and α2 of the space straight line vector on the projection image plane. The mapping results are shown in Table 2.

[0052]

[0053] Table 2 Results of axis vector mapping to substations 1 and 2

[0054]

[0055] The method for verifying the correctness of the spatial straight line vector to projection plane posture mapping result in this embodiment is as follows: after realizing the spatial straight line vector to projection plane posture mapping, the projection image plane angles α1 and α2 of the two substations are obtained, and the spatial straight line vector is reconstructed by the conventional central axis intersection method. The reconstruction result is L′(l′m′n′) T By comparing the consistency of L′ and L, the correctness of the mapping relationship between the space straight line vector and the projection plane posture can be verified. The comparison of L′ and L results is shown in Table 3.

[0056] Table 3 Comparison of results of L′ and L

[0057]

[0058] Where L′(l′m′n′) T The specific calculation process is:

[0059] ① The analytical expression of the image center axis in the substation image plane is:

[0060] Z·cos(α)+Y·sin(α)-P=0

[0061] The angle of the normal line of the x-axis centerline is angle α, with a range of [0, 2π). The distance from the origin to the straight line is P, with a range of [0, L), where L is the length from the origin to the vertex of the rectangle in the imaging area.

[0062] ②The plane equation in the camera coordinate system is:

[0063]

[0064] ③The equation of the plane rotated by the optical axis pointing to the elevation angle E and the azimuth angle A is:

[0065] d·X+e·Y+f·Z=0

[0066] in,

[0067]

[0068] Note: Since the actual tests are all performed at medium and long distances, the P / f value can be ignored, so the item where P / f is located can be omitted in the calculation process.

[0069] ④ Two equations are obtained at two stations

[0070]

[0071] ⑤ Solve the characteristic straight line L′(l′m′n′) by simultaneous solution T

[0072]

[0073] It can be seen from Table 3 that the L′ and L components completely correspond, indicating that the spatial straight line vector mapping result is correct.

Claims

1. A method for establishing a mapping relationship between a space straight line vector and a projection plane posture, characterized in that: The following steps are involved: (1) Normalized vector L0(abc) of the space line vector in the target coordinate system under the initial zero attitude condition T , through the yaw angle Ψ, pitch angle After the roll angle γ is rotated, the vector L(lmn) of the space straight line vector in the reference coordinate system at the calculation time is obtained. T ; (2) The vector L(lm n) T From the reference coordinate system, the camera optical axis is pointed to (A, E) and then transformed to the camera coordinate system, and L is obtained. C (X C Y C Z C ) T ; In the step (2), L C =R(-E)R(-A)L, where (3) L C (X C Y C Z C ) T Convert to image plane coordinate system l p (yz)T, (4) Obtain the angle α of the spatial straight line vector on the projection image plane, The step (4) obtains the two substation projection image plane angles α1 and α2, and uses the central axis intersection method to realize the spatial straight line vector reconstruction. The reconstruction result is L′(l′m′n′) T , compare the consistency of L′ and L, that is, verify the correctness of the mapping relationship between the space straight line vector and the projection plane posture.

2. The method for establishing a mapping relationship between a space straight line vector and a projection plane posture according to claim 1, characterized in that: The rotation matrix in step (1) is

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