Tester non-horizontal state high-speed camera exterior orientation element calibration method

Abstract

The invention provides a testing machine non-horizontal state high-speed camera exterior orientation element calibration method. The method comprises the following steps: 1, obtaining a space three-dimensional coordinate of a to-be-measured point; 2, constructing a reference plane by using the fuselage left side front-back pitching control points and the fuselage right side front-back pitching control points; 3, solving an intersection line P1P2 of the reference plane and the plane XOY of the measurement coordinate system; 4, converting the space three-dimensional coordinate of the point to be measured into a first temporary coordinate system; 5, converting the space three-dimensional coordinate of the point to be measured from the first temporary coordinate system to a second temporary coordinate system; 6, converting the space three-dimensional coordinate of the point to be measured under the second temporary coordinate system to be under the initial coordinate system of the testing machine; 7, converting the space three-dimensional coordinate of the point to be measured under the initial coordinate system of the testing machine to a third temporary coordinate system; and 8, performing coordinate conversion on the spatial three-dimensional coordinates of the to-be-measured point in the third temporary coordinate system to obtain the spatial three-dimensional coordinates of the to-be-measured point in the final airframe horizontal coordinate system.

Description

Calibration method for exterior orientation elements of high-speed camera in non-horizontal state of testing machine Technical Field

[0001] This invention relates to the field of flight test optical image testing, specifically to a method for calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a test aircraft. Background Technology

[0002] During flight testing, after a high-speed camera is installed on the test aircraft, its exterior orientation elements need to be calibrated. The analysis and calculation of the calibration data must be based on the aircraft's horizontal coordinate system. Achieving a level test aircraft frame requires coordination among multiple departments, including modification personnel and maintenance personnel, which is relatively time-consuming and labor-intensive. Therefore, it is necessary to study a method for calibrating the exterior orientation elements of the high-speed camera when the test aircraft is not in a level position. Summary of the Invention

[0003] This invention provides a method for calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine, which can solve the problem of time-consuming and labor-intensive calibration of optical image testing systems in a non-horizontal state of a testing machine.

[0004] Technical solution: A method for calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine, comprising: Step 1: In the measurement coordinate system, obtain the spatial three-dimensional coordinates of the point to be measured. The measurement coordinate system is the coordinate system defined by the measuring equipment. The origin is the mechanical center of the measuring equipment. The XOY plane is the horizontal plane passing through the origin. The Y-axis is defined by the measuring equipment after aiming at a certain direction. The Z-axis is perpendicular to the horizontal plane and is positive upwards. The X-axis and Z-axis form a right-hand system with the Y-axis.

[0005] Step 2: Using the left-side forward pitch control point (x1, y1, z1), the left-side rear pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), and the right-side rear pitch control point (x4, y4, z4), construct a reference plane with the equation Ax + By + Cz = 1. Step 3: Solve for the intersection line P1P2 between the reference plane and the XOY plane of the measurement coordinate system. Step 4: Construct a first temporary coordinate system O1-X1Y1Z1, with the Y-axis at P1P2 and the origin at P1. The plane X1O1Y1 coincides with the XOY plane of the measurement coordinate system, and the Z-axis is parallel to and oriented in the same direction as the Z-axis of the measurement coordinate system. The X and Z axes form a right-handed system with the Y-axis. Transform the three-dimensional spatial coordinates of the point to be measured to the first temporary coordinate system O1. -X1Y1Z1 below; Step 5: Construct a second temporary coordinate system, transforming the three-dimensional spatial coordinates of the point to be measured from the first temporary coordinate system to the second temporary coordinate system; The origin and Y-axis of the second temporary coordinate system coincide with the first temporary coordinate system O1-X1Y1Z1, and the X2O2Y2 plane of the second temporary coordinate system is the reference plane Ax+By+Cz=1; Step 6: Translate and rotate the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2 to the initial coordinate system O′-X′Y′Z′ of the testing machine; The initial coordinate system O′-X′Y′Z′ of the testing machine is defined as follows: The origin O′ is the rear longitudinal axis point M of the testing machine; The reference plane Ax+By+Cz=1 is formed by the four fuselage pitch control points, and this plane is translated vertically to pass through the origin O′ to form the plane X′O′Y′; The Y-axis is the projection of the vector of the line connecting the rear longitudinal axis point M and the front longitudinal axis point N of the machine body onto the X′O′Y′ plane. The X-axis is perpendicular to the Y-axis on the X′O′Y′ plane and points to the right side of the testing machine. The Z-axis is in a right-handed relationship with the X-axis and Y-axis.

[0006] Step 7: Transform the three-dimensional spatial coordinates of the point to be measured under the initial coordinate system O′-X′Y′Z′ of the testing machine to the third temporary coordinate system; the origin and Y-axis of the third temporary coordinate system are the same as those of the initial coordinate system O′-X′Y′Z′ of the testing machine, the X-axis is the vector connecting the left roll control point and the right roll control point of the fuselage, pointing from left to right, and the Z-axis forms a right-handed system with the X-axis and Y-axis.

[0007] Step 8: Transform the three-dimensional spatial coordinates of the point to be measured in the third temporary coordinate system to obtain the three-dimensional spatial coordinates of the point to be measured in the final horizontal coordinate system of the aircraft. The horizontal coordinate system of the aircraft is the coordinate system defined after the test frame is horizontal, with the origin at the rear longitudinal axis point M of the test machine; the Y-axis is the projection of the vector of the line connecting the rear longitudinal axis point M and the front longitudinal axis point N of the aircraft onto the horizontal plane, with the heading direction of the test machine as positive; the X-axis points to the right side of the test machine, and the Z-axis forms a right-handed system with the X-axis and Y-axis.

[0008] Furthermore, the points to be measured include: the left-side forward pitch control point (x1, y1, z1), the left-side backward pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), the right-side backward pitch control point (x4, y4, z4), the left-side roll control point (x5, y5, z5), and the right-side roll control point (x6, y6, z6); the front longitudinal axis point N and the rear longitudinal axis point M of the testing machine; and N marker points required for calibrating the exterior orientation elements of the high-speed camera, wherein N is greater than or equal to 3.

[0009] Furthermore, step 2 includes: substituting the left-side forward pitch control point (x1, y1, z1), the left-side rearward pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), and the right-side rearward pitch control point (x4, y4, z4) into the formula. Solve for the plane normal vectors (A, B, C) of the reference plane, where i is 1 to 4.

[0010] Furthermore, step 3 includes: Step 31: The coordinates of the intersection point P1 of the plane Ax+By+Cz=1 and the OX axis are ( Step 32: The coordinates of the intersection point P2 of plane Ax+By+Cz=1 and the OY axis are (0, 0, 0); Step 33: Determine the intersection line P1P2 based on the intersection point P1 and the intersection point P2.

[0011] Furthermore, step 4 includes: Step 41: Based on intersection point P1 and intersection point P2, using the formula... Step 42: Calculate the first rotation angle θ1; Using the first coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured in the measurement coordinate system to the first temporary coordinate system O1-X1Y1Z1, where the first coordinate translation and rotation formula is: .

[0012] Furthermore, step 5 includes: Step 51: If A*B*C>0, use the calculation formula Calculate the second rotation angle If A*B*C<0, use the calculation formula. Calculate the second rotation angle Step 52: Using the second coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured in the first temporary coordinate system O1-X1Y1Z1 to the second temporary coordinate system O2-X2Y2Z2. The second coordinate translation and rotation formula is as follows: .

[0013] Furthermore, step 6 includes: Step 61: the coordinates of the longitudinal axis point M of the testing machine under the second temporary coordinate system O2-X2Y2Z2. Coordinates of the front vertical axis point N According to the formula Calculate the third rotation angle Step 62: Using the third coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2 to the initial coordinate system O′-X′Y′Z′ of the testing machine, where: the third coordinate translation and rotation formula is... .

[0014] Furthermore, step 7 includes: based on the left roll control point (x5, y5, z5) and the right roll control point (x6, y6, z6), according to the formula... Calculate the fourth rotation angle The three-dimensional spatial coordinates of the point to be measured under the initial coordinate system O′-X′Y′Z′ of the testing machine are determined according to the formula. Transform to the third temporary coordinate system; further, step 8 includes: based on the coordinates of the left side forward pitch point of the fuselage in the third temporary coordinate system. Coordinates of the left rearward pitch point of the fuselage and the fixed height difference corresponding to the horizontal level of the frame. According to the formula Calculate the fifth rotation angle The three-dimensional spatial coordinates of the point to be measured in the third temporary coordinate system are determined according to the formula. Then, coordinate transformation is performed to obtain the three-dimensional spatial coordinates of the point to be measured in the final horizontal coordinate system of the machine body.

[0015] In summary, this application provides a method for calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine. By measuring the horizontal control points of the testing machine and performing subsequent calculations, it achieves the same effect as measuring the marker points when the testing machine is set up horizontally, thus solving the problem of high-speed camera calibration in a non-horizontal state of the testing machine. Attached Figure Description

[0016] Figure 1 is a flowchart of coordinate system transformation for a method of calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine provided in this application.

[0017] Figure 2 is a schematic diagram of coordinate system transformation for a method of calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine provided in this application.

[0018] Figure 3 is a schematic diagram of the reconstruction of the horizontal coordinate system of the test machine in a method for calibrating the external orientation elements of a high-speed camera in a non-horizontal state according to the present application. Detailed Implementation

[0019] As shown in Figure 1, this application provides a method for calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine. The specific implementation steps are as follows: Step 1: Obtain the spatial three-dimensional coordinates of the point to be measured in the measurement coordinate system.

[0020] The measurement coordinate system is defined by the measuring equipment. The origin is the mechanical center of the measuring equipment. The XOY plane is a horizontal plane passing through the origin. The Y-axis is defined by the measuring equipment after aiming at a certain direction. The Z-axis is perpendicular to the horizontal plane and is positive. The X-axis and Z-axis form a right-handed system with the Y-axis.

[0021] The measurement points include: ① the left front pitch control point (x1, y1, z1), the left rear pitch control point (x2, y2, z2), the right front pitch control point (x3, y3, z3), the right rear pitch control point (x4, y4, z4), the left roll control point (x5, y5, z5), and the right roll control point (x6, y6, z6); ② the front longitudinal axis point N and the rear longitudinal axis point M of the testing machine; ③ N marker points required for calibration of the exterior orientation elements of the high-speed camera, where N is greater than or equal to 3.

[0022] Step 2: Using the left-side forward pitch control point (x1, y1, z1), the left-side rearward pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), and the right-side rearward pitch control point (x4, y4, z4), construct a reference plane with the equation Ax + By + Cz = 1.

[0023] Specifically, step 2 includes: substituting the left-side forward pitch control point (x1, y1, z1), the left-side rearward pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), and the right-side rearward pitch control point (x4, y4, z4) into the formula. Step 3: Solve for the plane normal vectors (A, B, C) of the reference plane, where i is 1~4; Step 4: Solve for the intersection line P1P2 of the reference plane and the XOY plane of the measurement coordinate system.

[0024] Specifically, as shown in Figure 2, step 3 includes: Step 31: The coordinates of the intersection point P1 of the plane Ax+By+Cz=1 and the OX axis are ( Step 32: The coordinates of the intersection point P2 of plane Ax+By+Cz=1 and the OY axis are (0, 0, 0); Step 33: Determine the intersection line P1P2 based on the intersection point P1 and the intersection point P2.

[0025] Step 4: Construct a first temporary coordinate system O1-X1Y1Z1 and obtain the three-dimensional spatial coordinates of the point to be measured under the first temporary coordinate system O1-X1Y1Z1; the Y-axis of the first temporary coordinate system O1-X1Y1Z1 is P1P2, the origin is P1, the plane X1O1Y1 coincides with the plane of the measurement coordinate system XOY, the Z-axis is parallel to the Z-axis of the measurement coordinate system and has the same direction, and the X-axis and Z-axis form a right-handed system with the Y-axis.

[0026] Specifically, step 4 includes: Step 41: Based on intersection point P1 and intersection point P2, use the formula Calculate the first rotation angle Step 42: Using the first coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured in the measurement coordinate system to the first temporary coordinate system O1-X1Y1Z1. The first coordinate translation and rotation formula is: .

[0027] Step 5: Construct a second temporary coordinate system and obtain the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2; the origin and Y-axis of the second temporary coordinate system coincide with the first temporary coordinate system O1-X1Y1Z1, and the X2O2Y2 plane of the second temporary coordinate system is the reference plane Ax+By+Cz=1.

[0028] Specifically, as shown in Figure 2, step 5 includes: Step 51: If A*B*C>0, use the calculation formula Calculate the second rotation angle If A*B*C<0, use the calculation formula. Calculate the second rotation angle Step 52: Using the second coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured in the first temporary coordinate system O1-X1Y1Z1 to the second temporary coordinate system O2-X2Y2Z2. The second coordinate translation and rotation formula is as follows: .

[0029] Step 6: Translate and rotate the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2 to the initial coordinate system O′-X′Y′Z′ of the testing machine.

[0030] As shown in Figure 3, the initial coordinate system O′-X′Y′Z′ of the testing machine is defined as follows: the origin O′ is the rear longitudinal axis point M of the testing machine; a reference plane is formed by the four fuselage pitch control points, and this plane is translated vertically to pass through the origin O′ to form the plane X′O′Y′; the Y-axis is the projection of the vector of the line connecting the rear longitudinal axis point M and the front longitudinal axis point N on the X′O′Y′ plane; the X-axis is perpendicular to the Y-axis on the X′O′Y′ plane and points to the right side of the testing machine; the Z-axis is a right-handed system with the X-axis and Y-axis.

[0031] Specifically, step 6 includes: Step 61: The coordinates of the longitudinal axis point M of the testing machine under the second temporary coordinate system O2-X2Y2Z2 Coordinates of the front vertical axis point N According to the formula Calculate the third rotation angle .

[0032] Step 62: Using the third coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2 to the initial coordinate system O′-X′Y′Z′ of the testing machine, where: the third coordinate translation and rotation formula is... .

[0033] Step 7: Transform the three-dimensional spatial coordinates of the point to be measured under the initial coordinate system O′-X′Y′Z′ of the testing machine to the third temporary coordinate system; specifically, this includes: based on the left roll control point (x5, y5, z5) and the right roll control point (x6, y6, z6) of the fuselage, according to the formula... Calculate the fourth rotation angle The three-dimensional spatial coordinates of the point to be measured under the initial coordinate system O′-X′Y′Z′ of the testing machine are determined according to the formula. Transform to the third temporary coordinate system.

[0034] The third temporary coordinate system is defined as follows: the origin and the Y-axis are the same as the initial coordinate system O′-X′Y′Z′ of the test machine; the X-axis is the vector connecting the left roll control point and the right roll control point of the fuselage, pointing from left to right; and the Z-axis forms a right-handed system with the X-axis and Y-axis.

[0035] Step 8: Perform coordinate transformation on the three-dimensional spatial coordinates of the point to be measured in the third temporary coordinate system to obtain the three-dimensional spatial coordinates of the point to be measured in the final horizontal coordinate system of the body.

[0036] Specifically, this includes: based on the coordinates of the left forward pitch point of the fuselage in the third temporary coordinate system. Coordinates of the left rearward pitch point of the fuselage and the fixed height difference corresponding to the horizontal level of the frame. According to the formula Calculate the fifth rotation angle The three-dimensional spatial coordinates of the point to be measured in the third temporary coordinate system are determined according to the formula. Then, coordinate transformation is performed to obtain the three-dimensional spatial coordinates of the point to be measured in the final horizontal coordinate system of the machine body.

[0037] Among them, the horizontal coordinate system of the aircraft body is the coordinate system defined after the test frame is horizontal, with the origin at the rear longitudinal axis point M of the test machine; the Y-axis is the projection of the vector of the line connecting the rear longitudinal axis point M and the front longitudinal axis point N of the aircraft body on the horizontal plane, with the heading direction of the test machine as positive; the X-axis points to the right side of the test machine, and the Z-axis forms a right-hand system with the X-axis and Y-axis.

[0038] It should be noted that, This is a known value, representing the height difference between the forward pitch control point and the rear pitch control point. If the forward pitch control point is higher in the horizontal state, this value is positive; if the forward pitch control point is lower in the horizontal state, this value is negative.

Claims

1. A method for calibrating the exterior orientation elements of a high-speed camera in a non-horizontal state of a testing machine, characterized in that, The process includes: Step 1: Obtaining the three-dimensional spatial coordinates of the point to be measured in the measurement coordinate system; Step 2: Constructing a reference plane using the left-side forward pitch control point (x1, y1, z1), the left-side rearward pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), and the right-side rearward pitch control point (x4, y4, z4), with the plane equation Ax + By + Cz = 1; Step 3: Solving for the intersection line P1P2 between the reference plane and the XOY plane of the measurement coordinate system; Step 4: Constructing a first temporary coordinate system O1-X1Y1Z1, and transforming the three-dimensional spatial coordinates of the point to be measured to the first temporary coordinate system O1-X1Y1Z1. Step 5: Construct a second temporary coordinate system and transform the three-dimensional spatial coordinates of the point to be measured from the first temporary coordinate system to the second temporary coordinate system; Step 6: Translate and rotate the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2 to the initial coordinate system O′-X′Y′Z′ of the testing machine; Step 7: Transform the three-dimensional spatial coordinates of the point to be measured under the initial coordinate system O′-X′Y′Z′ of the testing machine to the third temporary coordinate system; Step 8: Perform coordinate transformation on the three-dimensional spatial coordinates of the point to be measured under the third temporary coordinate system to obtain the final three-dimensional spatial coordinates of the point to be measured under the horizontal coordinate system of the machine body.

2. The method according to claim 1, characterized in that, The points to be measured include: the left front pitch control point (x1, y1, z1), the left rear pitch control point (x2, y2, z2), the right front pitch control point (x3, y3, z3), the right rear pitch control point (x4, y4, z4), the left roll control point (x5, y5, z5), and the right roll control point (x6, y6, z6); the front longitudinal axis point N and the rear longitudinal axis point M of the testing machine; and N marker points required for calibrating the exterior orientation elements of the high-speed camera, wherein N is greater than or equal to 3.

3. The method according to claim 1, characterized in that, Step 2 includes: substituting the left-side forward pitch control point (x1, y1, z1), the left-side rearward pitch control point (x2, y2, z2), the right-side forward pitch control point (x3, y3, z3), and the right-side rearward pitch control point (x4, y4, z4) into the formula. Solve for the plane normal vectors (A, B, C) of the reference plane, where i is 1 to 4.

4. The method according to claim 1, characterized in that, Step 3 includes: Step 31: The coordinates of the intersection point P1 of the plane Ax+By+Cz=1 and the OX axis are ( Step 32: The coordinates of the intersection point P2 of plane Ax+By+Cz=1 and the OY axis are (0, 0, 0); Step 33: Determine the intersection line P1P2 based on the intersection point P1 and the intersection point P2.

5. The method according to claim 1, characterized in that, Step 4 includes: Step 41: Based on intersection point P1 and intersection point P2, use the formula Step 42: Calculate the first rotation angle θ1; Using the first coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured in the measurement coordinate system to the first temporary coordinate system O1-X1Y1Z1, where the first coordinate translation and rotation formula is: 。 6. The method according to claim 1, characterized in that, Step 5 includes: Step 51: If A*B*C>0, use the calculation formula Calculate the second rotation angle If A*B*C<0, use the calculation formula. Calculate the second rotation angle Step 52: Using the second coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured in the first temporary coordinate system O1-X1Y1Z1 to the second temporary coordinate system O2-X2Y2Z2. The second coordinate translation and rotation formula is as follows: 。 7. The method according to claim 1, characterized in that, Step 6 includes: Step 61: The coordinates of the longitudinal axis point M of the testing machine under the second temporary coordinate system O2-X2Y2Z2 Coordinates of the front vertical axis point N According to the formula Calculate the third rotation angle Step 62: Using the third coordinate translation and rotation formula, transform the three-dimensional spatial coordinates of the point to be measured under the second temporary coordinate system O2-X2Y2Z2 to the initial coordinate system O′-X′Y′Z′ of the testing machine. The third coordinate translation and rotation formula is as follows: 。 8. The method according to claim 1, characterized in that, Step 7 includes: based on the left roll control point (x5, y5, z5) and the right roll control point (x6, y6, z6), according to the formula... Calculate the fourth rotation angle The three-dimensional spatial coordinates of the point to be measured under the initial coordinate system O′-X′Y′Z′ of the testing machine are determined according to the formula. Transform to the third temporary coordinate system.

9. The method according to claim 1, characterized in that, Step 8 includes: using the coordinates of the left side of the fuselage forward pitch point in the third temporary coordinate system. Coordinates of the left rearward pitch point of the fuselage and the fixed height difference corresponding to the horizontal level of the frame. According to the formula Calculate the fifth rotation angle The three-dimensional spatial coordinates of the point to be measured in the third temporary coordinate system are determined according to the formula. Then, coordinate transformation is performed to obtain the three-dimensional spatial coordinates of the point to be measured in the final horizontal coordinate system of the machine body.

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