Image seeker tracking performance test method based on simulated moving target

Abstract

The invention discloses an image seeker tracking performance test method based on a simulated moving target, which comprises the following steps of: generating a simulated target and a moving track through a target simulation computer, projecting the simulated target and the moving track to a curtain, and tracking the simulated target on the curtain by an image seeker to realize the tracking speed precision and the maximum tracking speed test; then the size of the target under the tracking distance is obtained through calculation, the target simulation computer generates a simulation target and a motion trail and projects the simulation target and the motion trail to the curtain, the image seeker tracks the simulation target on the curtain through the reflective collimator, and tracking distance testing is achieved. A dynamic simulation target is provided for image seeker tracking, meanwhile, external field environment factors such as target definition, light intensity and target shielding are introduced, and the method has the advantages that the testing method is simple, the testing environment is easy to build, and online tracking debugging and synchronous testing are facilitated.

Description

Technical Field

[0001] This invention relates to the field of seeker technology, and more specifically to a method for testing the tracking performance of an image seeker based on simulated moving targets. Background Technology

[0002] The most critical function of an image seeker during use is dynamic target tracking. Therefore, it is necessary to test the tracking performance of the image seeker beforehand. Tracking performance test indicators include maximum tracking distance, tracking speed accuracy, and maximum tracking speed. Tracking performance testing can be conducted in both indoor and outdoor environments. Outdoor testing uses vehicles or vehicles carrying crosshairs to simulate actual targets in a natural environment, and then the seeker tracks the moving vehicle for testing. If outdoor testing is to be conducted directly after the image seeker is debugged, a suitable test site and test target must first be selected. Generally, the image seeker should be able to see the test target at a tracking distance greater than the required specification. Secondly, significant manpower and resources are needed for overall coordination and on-site support before and after the test. It is also necessary to ensure that the outdoor environment (such as weather conditions and target occlusion) meets the test requirements. Furthermore, if the test results are unsatisfactory or problems arise, the image tracking algorithm needs to be debugged, optimized, and verified, which takes a considerable amount of time. Therefore, it is generally preferred to conduct necessary tests in a laboratory.

[0003] Current laboratory testing methods generally employ professional target simulators to generate simulated targets, while motion equipment such as five-axis turntables drives the target simulator to perform regular movements. However, target simulators simulate distant targets through specialized optical systems, which are expensive to manufacture and maintain. Once a malfunction occurs, the repair cycle is also very long. At the same time, the motion equipment used requires a large space for a long time, and there are certain dangers to personnel and products during use. Therefore, it is not convenient for R&D personnel to debug products on-site. Furthermore, different image guides require custom-made tooling to be installed on the turntable, which increases both cost and cycle time. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, and from the perspective of the need for image seeker tracking performance testing, this invention proposes an image seeker tracking performance testing method based on simulated moving targets.

[0005] This invention adopts the following technical solution: a method for testing the tracking performance of an image seeker based on a simulated moving target, which uses a testing system consisting of a screen, a projector, an image seeker, a control computer, a target simulation computer, and a reflective collimator. The specific testing method is as follows:

[0006] 1) A target simulation computer generates an image on the screen as a simulated target, and the target image is generated at each moment with the projector frame rate as the time point, thus forming the motion trajectory of the target image.

[0007] 2) Test the tracking speed performance of the image seeker, including tracking speed accuracy and maximum tracking speed tests. During the test, the image seeker is placed on the test bench using a fixture bracket, and the projector is also placed on the test bench. The projector is connected to the target simulation computer via a video cable. The screen is arranged in front of the image seeker and the projector to display the simulated target and its motion. The control computer is connected to the image seeker via a fixture cable to simulate the flight control sending commands to the image seeker, receiving data in real time, displaying video images, and the seeker's status.

[0008] 3) Test the tracking distance performance of the image seeker. During the test, the collimator is placed on the optical platform, and the image seeker is placed on the test table with the collimator level and facing it via a fixture bracket. The projector is also placed on the test table, and the screen is arranged in front of the image seeker and the projector to display the simulated target and its motion. The projector is connected to the target simulation computer via a video cable. The target simulation computer generates the simulated target and its motion trajectory, and the projector projects the simulated target onto the screen in front of it. The control computer is connected to the image seeker via a fixture cable. The control computer simulates the flight controller sending commands to the image seeker, receiving data, and displaying the image seeker's status in real time. During the test, if the image seeker can stably track the target, it means that the seeker meets the tracking distance requirement; otherwise, it does not meet the tracking distance requirement.

[0009] Furthermore, the simulated target image generated by the target simulation computer in step 1) is achieved through the following method: In tracking tests, the motion is typically uniformly accelerated. Based on the uniform acceleration parameters, projection parameters, seeker parameters, and target parameters, the target simulation computer allocates the motion angles for each stage of acceleration and uniform motion, generating the pixel coordinates of the target image at each frame time. This allows us to determine the simulated uniformly accelerated motion of the target within the line-of-sight angle range of the image seeker. The calculation method is as follows:

[0010] (1)

[0011] In the formula:

[0012] d is the distance from the center of the image guide head to the screen; / The lengths of each pixel in the yaw and pitch directions are calculated from the actual screen dimensions l and h and the display resolution (W, H), using the following formula:

[0013] (2)

[0014] / These represent the motion angles at a given moment in the yaw / pitch directions, and their calculation formulas are as follows:

[0015] (3)

[0016] in For projection frame rate, x and These are the velocity values ​​during uniformly accelerated motion.

[0017] Further, the method for testing the tracking speed performance of the image seeker described in step 2) is as follows: First, the image seeker is powered on, the target simulation computer is run to select the target and its motion mode, and the target is projected onto the screen; then, the control computer sends a tracking command to the image seeker to control the image seeker to stably track the target; after the target motion ends, the image seeker tracking is stopped, and the data recorded by the control computer is analyzed and processed using MATLAB. The speed value of the image seeker during the uniform motion phase is taken, and the difference between it and the uniform speed set by the simulated target is taken. The root mean square error value is the tracking speed accuracy, and the calculation formula is:

[0018] (4).

[0019] Further, the method for testing the tracking distance performance of the image seeker described in step 3) is as follows: First, calculate the simulated target size. Based on the target distance, target size, and focal length, calculate the image size of the tracked target. The calculation formula is:

[0020] (5)

[0021] in:

[0022] The target tracking distance; To track target size; This is the focal length value for visible light; The size of the target in the visible light image;

[0023] Then, the target simulation computer selects the target and its motion mode, projects the target onto a screen, powers on the image seeker, and displays a visible light video image in the control computer via a collimator. The control computer then controls the movement of the image seeker to center the simulated target in the image. The control computer acquires the coordinates of the simulated target in the visible light video image and calculates the difference between the x and y coordinates to obtain the size of the simulated target. ,according to and The size of the simulated target is adjusted in the target simulation software to ensure that the simulated target size is correct. As close as possible to and no more than Then, the control computer sends tracking commands to the image seeker to control the image seeker to stably track the target. If the visible light image is not clear enough, the back clipping of the visible light camera of the image seeker is adjusted first to make the video image through the collimator clear. After the target movement ends, the image seeker stops tracking.

[0024] Compared with existing technologies, this invention provides a dynamically simulated target for image seeker tracking, while introducing external environmental factors such as target sharpness, light intensity, and target occlusion. It features a simple testing method, easy-to-build testing environment, and facilitates simultaneous online tracking, debugging, and testing. Its beneficial effects are as follows:

[0025] 1) It has few restrictions on the test site and environment, does not require a large space, and the test system is easy, quick and flexible to set up and operates without danger;

[0026] 2) The professional simulator was eliminated, and target simulation software was designed. The simulation of target generation and motion was achieved by using software and projection, thus saving the cost and maintenance cycle of precision instruments and equipment.

[0027] 3) No additional testing fixtures are required, reducing test preparation time;

[0028] 4) The image seeker tracking algorithm is easy to debug and verify online, and can be debugged and tested simultaneously;

[0029] 5) The test can be simulated with some external environmental conditions, such as considering the impact of target image clarity and light intensity on target tracking, and simulating target occlusion, etc.

[0030] 6) By combining software with projection and a collimator, the tracking distance of the image seeker can be determined in the indoor test, laying the foundation for outdoor verification;

[0031] 7) The testing method is simple and applicable, and can be used with equipment such as photoelectric pods that have image tracking capabilities. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an image seeker tracking speed testing system.

[0033] Figure 2 This is a schematic diagram of an image seeker tracking distance testing system.

[0034] In the diagram: 1. Screen, 2. Projector, 3. Test stand, 4. Image guide head, 5. Tooling bracket, 6. Control computer, 7. Tooling cable, 8. Video cable, 9. Target simulation computer, 10. Optical platform, 11. Reflective collimator. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] This invention, based on the current requirements for image seeker tracking performance testing, proposes a method for testing the tracking performance of an image seeker using simulated moving targets. This method includes testing tracking performance indicators such as tracking speed accuracy, maximum tracking speed, and tracking distance. The testing method utilizes a screen 1, a projector 2, an image seeker 4, a control computer 6, a target simulation computer 9, and a reflective collimator 11. The specific operation method is as follows:

[0037] 1) The target simulation computer 9 uses a graphical interface software to program an image such as a circular dot or a cross shape to be generated on the screen 1 as a simulated target. The target image is generated at each moment with the projector frame rate as the time point, thus forming the motion trajectory of the target image.

[0038] In tracking tests, the motion is typically uniformly accelerated. The target simulation computer 9, based on uniform acceleration parameters, projection parameters, seeker parameters, and target parameters, allocates motion angles for each stage of acceleration and uniform motion, generating the pixel coordinates of the target image at each frame time. Thus, the uniform acceleration motion of the simulated target within the line-of-sight angle range of the image seeker 4 is determined, and the calculation method is as follows:

[0039] (1)

[0040] In the formula:

[0041] d is the distance from the center of the image guide head 4 to the screen 1; / The lengths of each pixel in the yaw and pitch directions are calculated from the actual dimensions l and h of screen 1 and the display resolution (W, H), and the calculation formula is as follows:

[0042] (2)

[0043] / Let be the angle of motion at a certain moment in the yaw / pitch direction, respectively. The calculation formula is as follows:

[0044] (3)

[0045] in: For projection frame rate; x and These are the velocity values ​​during uniformly accelerated motion.

[0046] 2) Test the tracking speed performance of image seeker 4, see [link / reference]. Figure 1 This is a schematic diagram of the image seeker 4 tracking speed test system. The test method for its tracking speed accuracy and maximum tracking speed includes the following steps:

[0047] Step 1: The image guide head 4 is placed on the test bench 3 through the tooling bracket 5, and the projector 2 is also placed on the test bench 3. It is necessary to ensure that when the servo mechanism of the image guide head 4 moves to the extreme positions on both sides, the projector 2 will not block the visible light video image.

[0048] Step 2: Place the screen 1 at a distance in front of the image guide head 4 and the projector 2 to display the simulated target and its movement, and ensure that this distance covers the maximum angular range that the image guide head 4 can observe;

[0049] Step 3: Connect the tooling cable 7 between the image guide head 4 and the control computer 6, and connect the video cable 8 between the projector 2 and the target simulation computer 9;

[0050] Step 4: Run the target simulation computer 9 to generate a simulated target, which is usually a circular target. At this time, the simulated target is projected onto the screen 1 through the projector 2.

[0051] Step 5: Determine the screen size and other parameters for projection, and set these parameters in the target simulation computer 9;

[0052] Step 6: Power on the image seeker 4, run the control computer 6, simulate the flight controller to send commands to the image seeker 4 to track the target, and display the video image and status of the image seeker 4 in real time and record information;

[0053] Step 7: The target simulation computer 9 sets the target to undergo uniform acceleration motion, and its velocity V during the uniform phase should be kept within the visible light field of view;

[0054] Step 8: After the target movement ends, stop the computer 6 from recording and exit the image seeker 4 from tracking mode;

[0055] Step 9: Analyze and process the data recorded by the control computer 6 using MATLAB. Take the velocity value of the image guide head 4 during the uniform motion phase, and calculate the difference between it and the uniform velocity value set for the simulated target. The root mean square error value is the tracking speed accuracy. The calculation formula is as follows:

[0056] (4);

[0057] Step 10: Repeat steps (6)-(7) to continuously increase the speed value during the constant speed phase until the image seeker 4 is about to lose its ability to stably track the simulated target, which is the maximum tracking speed of the image seeker 4.

[0058] 3) Test the tracking distance performance of the image seeker. Figure 2 This is a schematic diagram of an image seeker tracking distance testing system. The tracking distance testing method includes the following steps:

[0059] Step 1: Place the reflective collimator 11 on the optical platform 10;

[0060] Step 2: The image guide head 4 is placed on the test table 3 through the tooling bracket 5, keeping it basically level with the reflective collimator 11 and facing the collimator 11.

[0061] Step 3: Place the projector on the test platform 3, and place the screen 1 a distance in front of the projector 2 to display the simulated target and its movement.

[0062] Step 4: Connect the tooling cable 7 between the image guide head 4 and the control computer 6, and connect the video cable 8 between the projector 2 and the target simulation computer 9;

[0063] Step 5: Run the target simulation computer 9 to generate a simulated target, which is usually a circular target. At this time, the simulated target is projected onto the screen 1 through the projector 2.

[0064] Step 6: Power on the image guide head 4 and run the control computer 6. The control computer 6 displays the visible light video image of the image guide head 4 through the collimator 11.

[0065] Step 7: Calculate the visible light image size of the tracked target based on the target distance, target size, and visible light focal length, using the following formula:

[0066] (5)

[0067] Right now:

[0068] (6)

[0069] in:

[0070] The target tracking distance; To track target size; This is the focal length value for visible light; The size of the visible light image;

[0071] Step 8: Calculate the image tracking pixels according to formula (3) and the visible light pixel size, and verify the tracking conditions as follows:

[0072] (7)

[0073] in:

[0074] Pixel size; Pixels in the horizontal direction; For pixels in the vertical direction; if and If all values ​​are greater than or equal to 6, it means that the Johnson criterion is met, i.e., the tracking requirement is met; if not, it means that the target cannot be tracked.

[0075] Step 9: The computer 6 acquires the coordinates of the simulated target in the video image, and then calculates the difference between the x and y coordinates, which is the size of the simulated target. ;

[0076] Step 10: Simulate target size and visible light imaging size For comparison, the nine simulated targets were corrected using a target simulation computer to ensure that the simulated target size was maintained. As close as possible to and no more than value;

[0077] Step 11: The control computer 6 sends instructions to the image guide head 4 to track the target, and then simply moves the position of the image guide head 4. Only when the image guide head 4 can stably track the target can the next step be carried out. If the target image is not clear enough, causing the image guide head 4 to be unable to stably track the target, the back focal length of the visible light camera of the image guide head 4 needs to be adjusted to ensure that the video image through the collimator 11 must be clear.

[0078] Step 12: The target simulation computer 9 sets the target to undergo uniform acceleration motion, sets a uniform speed, and ensures that the uniform speed phase is within the visible light field. During the test, a light source can be introduced to simulate the intensity of the external light field.

[0079] Step 13: After the target movement ends, stop the computer 6 from recording and exit the image seeker 4 tracking state. If the image seeker 4 can stably track the target, it means that the tracking distance meets the performance requirements; otherwise, it does not meet the tracking distance requirements.

[0080] The embodiments described above are merely a part of the present invention, and not all of them. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing the tracking performance of an image-guided head based on simulated moving targets, characterized in that, The test system consists of a screen (1), a projector (2), an image guide head (4), a control computer (6), a target simulation computer (9), and a reflective collimator (11). The specific test method is as follows:

1. An image is generated on the screen (1) by the target simulation computer (9) as a simulated target, and the target image is generated at each moment with the projector frame rate as the time point, thus forming the motion trajectory of the target image; 2. Testing the tracking speed performance of the image seeker, including tracking speed accuracy and maximum tracking speed testing. During the test, the image seeker (4) is placed on the test bench (3) via a fixture bracket (5), and the projector (2) is also placed on the test bench (3). The projector (2) is connected to the target simulation computer (9) via a video cable (8). The screen (1) is placed in front of the image seeker (4) and the projector (2) to display the simulated target and the target's movement. The control computer (6) is connected to the image seeker (4) via a fixture cable (7) to simulate the flight control sending commands to the image seeker, receiving data in real time, displaying video images and the seeker's status.

3. Testing the tracking distance performance of the image seeker: During the test, the collimator (11) is placed on the optical platform (10), and the image seeker (4) is placed on the test bench (3) with the collimator (11) level and facing the collimator (11) via the tooling bracket (5); the projector (2) is also placed on the test bench (3), and the screen (1) is placed in front of the image seeker (4) and the projector (2) to display the simulated target and the target's movement mode; the projector (2) is connected to the target simulation computer (9) via a video cable (8). The target simulation computer (9) generates a simulated target and its trajectory, and the projector (2) projects the simulated target onto the screen (1) in front of it. The control computer (6) is connected to the image seeker (4) via a tooling cable (7). The control computer (6) is used to simulate the flight controller sending instructions to the image seeker (4), receiving data, and displaying the status of the image seeker (4) in real time. During the test, if the image seeker can stably track the target, it means that the seeker meets the tracking distance requirement; otherwise, it does not meet the tracking distance requirement.

2. The method for testing the tracking performance of an image-guided head based on simulated moving targets according to claim 1, characterized in that, The simulated target image generated by the target simulation computer (9) in step one is achieved through the following method: In the tracking test, the motion is usually uniformly accelerated. Based on the uniform acceleration parameters, projection parameters, seeker and target parameters, the target simulation computer (9) allocates the motion angles for each stage of acceleration and uniform speed, and generates the pixel coordinate positions of the target image at each frame time. Thus, the uniform acceleration motion of the target within the line-of-sight angle range of the image seeker (4) is determined, and the calculation method is as follows: In the formula: d is the distance from the center of the image guide head (4) to the screen (1); / The lengths of each pixel in the yaw and pitch directions are calculated from the actual screen dimensions l and h and the display resolution (W, H), respectively. The calculation formula is as follows: / These represent the motion angles at a given moment in the yaw / pitch directions, and their calculation formulas are as follows: in For projection frame rate, x and These are the velocity values ​​during uniformly accelerated motion.

3. The method for testing the tracking performance of an image-guided head based on a simulated moving target according to claim 2, characterized in that, The tracking speed performance test method of the image guide head (4) in step two is as follows: First, the image guide head (4) is powered on, the target simulation computer (9) is run to select the target and the motion mode, and the target is projected onto the screen (1); then the control computer (6) is run to send a tracking command to the image guide head (4) to control the image guide head (4) to stably track the target; after the target motion ends, the image guide head (4) exits the tracking, and the data recorded by the control computer (6) is analyzed and processed by MATLAB. The speed value of the image guide head (4) in the uniform motion stage is taken, and the difference between it and the uniform speed set by the simulated target is taken. The root mean square error value is the tracking speed accuracy. The calculation formula is: 。 4. The method for testing the tracking performance of an image-guided head based on a simulated moving target according to claim 3, characterized in that, The tracking distance performance test method of the image seeker (4) in step three is as follows: First, calculate the size of the simulated target. Based on the target distance, target size, and focal length, calculate the image size of the tracked target. The calculation formula is: in: The target tracking distance; To track target size; This is the focal length value for visible light; The size of the target in the visible light image; Then, the target simulation computer (9) selects the target and its motion mode and projects the target onto the screen (1). The image guide head (4) is powered on and displays a visible light video image in the control computer (6) through the collimator (11). The control computer (6) controls the movement of the image guide head (4) so ​​that the simulated target is in the center of the image. The control computer (6) obtains the coordinate values ​​of the simulated target in the visible light video image and then calculates the difference between the x and y coordinates to obtain the size of the simulated target. ,according to and The size of the simulated target is adjusted in the target simulation software to ensure that the simulated target size is correct. As close as possible to and no more than Then the control computer (6) sends a tracking command to the image guide (4) to control the image guide (4) to stably track the target. If the clarity of the visible light image is insufficient, the back clip of the visible light camera of the image guide (4) is adjusted first to make the video image through the collimator (11) clear. After the target moves, the image guide (4) stops tracking.

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