Method and system for rapidly measuring laser irradiation precision in external field

Abstract

The invention discloses a laser irradiation precision external field rapid measurement method and system, and belongs to the technical field of laser testing. The system comprises a hovering aircraft and a system frame carried on the hovering aircraft, and a light spot monitoring module, a target module and a power module are installed on the system frame. The light spot monitoring module is arranged opposite to the target module and is used for acquiring laser light spot image data on the target module and storing the laser light spot image data; the power supply module supplies power to system equipment. According to the external field rapid measurement method for the laser irradiation precision, a mode of combining laser spot energy monitoring and the unmanned rotorcraft is adopted, the laser irradiation precision is rapidly and efficiently measured in an external field environment, the requirement for a test site environment is low, only an intervisible airspace is needed, and rapid testing is easy.

Description

Technical Field

[0001] The invention belongs to the technical field of laser testing, and in particular relates to a method and system for rapid outfield measurement of laser irradiation accuracy. Background Art

[0002] In the fields of laser communication, laser ranging, laser lighting, etc., it is often necessary to direct a laser beam to a specific position in a certain area, which limits the accuracy of the laser beam's optical axis pointing to meet certain usage requirements. For the laser optical axis pointing accuracy test, it can be divided into two types: indoor laboratory test and outdoor test. The indoor laboratory test generally adopts an equivalent method, and only tests whether the laser performance indicators reach the design value, while the outdoor test generally simulates the actual use environment and comprehensively detects the actual laser irradiation accuracy under the influence of environmental factors. However, when conducting laser irradiation accuracy tests in the field, we usually face practical problems such as insufficient site distance, trees or terrain obstructions on the line of sight, and inability to find a suitable location for equipment installation. It takes a lot of time to find a suitable test site, which affects efficiency and progress. In addition, if the irradiation accuracy test is performed on a moving target, it is also necessary to build a motion platform that can set up the test equipment and a site with a corresponding motion track, which makes the test condition preparation process more complicated and difficult to achieve rapid measurement of laser irradiation accuracy. Summary of the invention

[0003] Technical issues to be solved:

[0004] In order to avoid the shortcomings of the prior art, the present invention provides a method and system for rapid outdoor measurement of laser irradiation accuracy, which adopts a combination of laser spot energy monitoring and a rotary-wing UAV to achieve rapid and efficient measurement of laser irradiation accuracy in an outdoor environment. The method has few requirements on the test site environment, only requires line of sight in the airspace, and is easy to test quickly.

[0005] The technical solution of the present invention is: a method for rapid outfield measurement of laser irradiation accuracy, the specific steps are as follows:

[0006] The spot monitoring module and the target module are integrated on the hovering aircraft; the target module includes a laser target plate with a central cross line and simulated target sources symmetrically arranged on both sides thereof;

[0007] After aligning the field of view center of the spot monitoring module with the crosshair center of the laser target plate, start the automatic image recording and storage function of the spot monitoring module;

[0008] Set the laser device to be tested as the take-off point of the hovering aircraft, control the hovering aircraft to fly to the specified position, face the laser target plate to the take-off direction, obtain the height and horizontal distance relative to the take-off point, and calculate the actual slant distance of the hovering aircraft relative to the take-off point;

[0009] The laser device to be tested uses the center positions of two simulated target sources as the target for light emission, and the laser spot image data is read by the spot monitoring module;

[0010] The spot energy centroid is calculated for the laser spot image to obtain the total deviation of the laser spot centroid on the k-th frame image relative to the crosshair center of the target plate;

[0011] Based on the total deviation of the mass center of the laser spot of the k-th frame image relative to the center of the crosshairs of the target plate, the total deviation angle of laser irradiation is calculated, which is the laser irradiation accuracy at the moment of the frame;

[0012] Repeat the above steps until the laser irradiation accuracy of all frame images is completed.

[0013] A further technical solution of the present invention is that the designated position is a position corresponding to the slant distance required by the irradiation distance index of the laser device to be measured.

[0014] A further technical solution of the present invention is: the actual slant distance L of the hovering aircraft relative to the take-off point is calculated as follows:

[0015]

[0016] Wherein, H is the vertical height of the hovering aircraft relative to the take-off point, and S is the horizontal distance of the hovering aircraft relative to the take-off point.

[0017] A further technical solution of the present invention is: the total deviation of the centroid of the laser spot on the k-th frame image relative to the center of the crosshairs of the target plate is calculated as follows:

[0018]

[0019]

[0020]

[0021] Among them, x k ,y k are the horizontal deviation and vertical deviation of the center of mass of the laser spot on the kth frame image relative to the center of the crosshairs of the target plate, respectively. i,j is the light intensity measurement value of the pixel in row i and column j, x i,j ,y i,j are the horizontal coordinate value and vertical coordinate value of the pixel in row i and column j, respectively. k is the total deviation.

[0022] A further technical solution of the present invention is that when calculating the total deviation, the energy of each pixel position of the image recorded by the light spot monitoring camera when no light is emitted needs to be deducted as the background to avoid interference from ambient stray light.

[0023] A further technical solution of the present invention is: the total deviation angle θ of the laser irradiation is k The calculation formula is:

[0024] A laser irradiation precision outfield rapid measurement system comprises a hovering aircraft and a system frame mounted thereon, wherein a spot monitoring module, a target module and a power module are installed on the system frame; the spot monitoring module is arranged opposite to the target module and is used to obtain and store the laser spot image data on the target module; the power module supplies power to the system equipment;

[0025] The relationship between the installation distance d between the light spot monitoring module and the target module, the effective field angle θ of the light spot monitoring module, and the target surface length D of the laser target plate is: d≥D·sinθ.

[0026] A further technical solution of the present invention is: the hovering aircraft is a rotary-wing UAV, which is connected to the system frame through a UAV air suspension mechanism.

[0027] A further technical solution of the present invention is: the light spot monitoring module includes a light spot monitoring camera, which is fixed on the system frame through a camera mounting bracket; the light spot monitoring camera is configured as an imaging detection camera with an automatic image recording and storage function, the imaging detection band matches the laser band to be tested, and the imaging detection field of view covers the target module; the camera mounting bracket has a two-dimensional direction adjustment structure of azimuth and pitch.

[0028] A method for measuring a moving target using a laser irradiation accuracy outfield rapid measurement system, the specific steps are as follows:

[0029] The spot monitoring module and the target module are integrated on the hovering aircraft; the target module includes a laser target plate with a central cross line and simulated target sources symmetrically arranged on both sides thereof;

[0030] After aligning the field of view center of the spot monitoring module with the crosshair center of the laser target plate, start the automatic image recording and storage function of the spot monitoring module;

[0031] Set the laser device to be tested as the take-off point of the hovering aircraft, control the hovering aircraft to fly according to the set trajectory, and make the laser target plate face the take-off direction, obtain the real-time height and horizontal distance of the flight relative to the take-off point, and calculate the actual slant distance of the hovering aircraft relative to the take-off point at different times;

[0032] The laser device to be tested uses the center positions of two simulated target sources as the target for light emission, and the laser spot image data is read by the spot monitoring module;

[0033] The spot energy centroid is calculated for the laser spot image to obtain the total deviation of the laser spot centroid on the k-th frame image relative to the crosshair center of the target plate;

[0034] Based on the total deviation of the mass center of the laser spot of the k-th frame image relative to the center of the crosshairs of the target plate, the total deviation angle of laser irradiation is calculated, which is the laser irradiation accuracy at the moment of the frame;

[0035] Repeat the above steps until the laser irradiation accuracy of all frame images is completed.

[0036] Beneficial Effects

[0037] The beneficial effects of the present invention are as follows: the present invention adopts a method combining laser spot energy monitoring with a rotary wing UAV, and only requires line of sight in the airspace to achieve rapid and efficient measurement of laser irradiation accuracy in an outdoor environment, avoiding practical problems such as insufficient distance to the outdoor site, trees or terrain blocking the line of sight, and finding no suitable equipment installation site. At the same time, by monitoring and calculating the deviation of the target laser spot centroid, the measurement error can be less than 0.1 pixel (the simulation calculation example based on the real data of the outdoor field is as follows Figure 2 , the errors in the horizontal and vertical directions are 0.07 pixels and 0.04 pixels respectively). BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention.

[0039] Figure 2 (a) Target energy distribution on each pixel of the detector, (b) Calculated number of pixels of the center of mass of the spot energy relative to the reference center.

[0040] Explanation of the reference numerals: 1. Light spot monitoring camera, 2. Camera mounting bracket, 3. Laser target plate, 4. Simulated target source, 5. Target mounting bracket, 6. Power supply, 7. Power supply mounting bracket, 8. System frame, 9. Rotary-wing UAV, 10. UAV aerial lifting mechanism. DETAILED DESCRIPTION

[0041] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0042] When testing the laser irradiation accuracy in the field, there are usually practical problems such as insufficient site distance, trees or terrain blocking the line of sight, and no suitable equipment installation location. The present invention provides a method for rapid field measurement of laser irradiation accuracy. The specific steps are as follows:

[0043] Step 1: Integrate a spot monitoring module and a target module on a hovering aircraft; the target module includes a laser target plate with a central crosshair and simulated target sources symmetrically arranged on both sides thereof;

[0044] Step 2: After aligning the field of view center of the spot monitoring module with the crosshair center of the laser target plate, start the automatic image recording and storage function of the spot monitoring module;

[0045] Step 3: Set the laser device to be tested as the take-off point of the hovering aircraft, control the hovering aircraft to fly to the specified position, face the laser target plate to the take-off direction, obtain the height and horizontal distance relative to the take-off point, and calculate the actual slant distance of the hovering aircraft relative to the take-off point;

[0046] Step 4: The laser device to be tested emits light at the center positions of two simulated target sources, and the laser spot image data is read by the spot monitoring module;

[0047] Step 5: Calculate the energy centroid of the laser spot image to obtain the total deviation of the laser spot centroid on the k-th frame image relative to the crosshair center of the target plate;

[0048] Step 6: Based on the total deviation of the laser spot mass center of the k-th frame image relative to the crosshair center of the target plate, calculate the total deviation angle of laser irradiation, which is the laser irradiation accuracy at the frame moment;

[0049] Step 7: Repeat the above steps until the laser irradiation accuracy of all frame images is completed.

[0050] The present invention combines laser spot energy monitoring with a rotary-wing UAV to achieve rapid and efficient measurement of laser irradiation accuracy in an outdoor environment. It also has the advantages of having fewer requirements on the test site environment, requiring only line of sight to the airspace, and being easy and quick to test.

[0051] The above technical solution is further described below with reference to the accompanying drawings and examples:

[0052] Reference Figure 1 As shown, the present embodiment is a laser irradiation accuracy outdoor rapid measurement system, including a spot monitoring module, a target module, a power module, a system frame 8, a rotor UAV 9 and a UAV air-hanging mechanism 10 which are fixedly connected to each other. The spot monitoring module, the target module and the power module are respectively fixedly mounted on the system frame, and the system frame is connected to the UAV air-hanging mechanism through its own adjustment ears, and the UAV air-hanging mechanism is connected to the rotor UAV.

[0053] Specifically, the spot monitoring module includes a spot monitoring camera 1 and a camera mounting frame 2, and the spot monitoring camera 1 is fixedly mounted on the camera mounting frame 2, and the camera mounting frame 2 is fixedly mounted on the system frame 8. The spot monitoring camera 1 is configured as an imaging detection camera with an automatic image recording and storage function, and the imaging detection band matches the laser band to be tested, and the imaging detection field of view covers the target module. The camera mounting frame 2 has a two-dimensional direction adjustment structure of azimuth and pitch.

[0054] Specifically, the target module includes a laser target plate 3, a simulated target source 4, and a target mounting frame 5, and the laser target plate 3 and the simulated target source 4 are respectively fixedly mounted on the target mounting frame 5, and the target mounting frame is fixedly mounted on the system frame 8.

[0055] Specifically, the laser target plate 3 is configured as a diffuse reflection target engraved with a crosshair, and is fixedly mounted at the center of the target mounting frame 5 , and the effective size of the target surface is larger than the size of the laser spot to be measured.

[0056] Specifically, the simulated target source 4 is configured as two halogen lamps powered by batteries carried by the lamps, which are fixedly mounted on both sides of the target mounting frame 5 and are symmetrical with respect to the crosshair center of the laser target plate 3 .

[0057] Specifically, the relationship between the installation distance d between the spot monitoring camera and the laser target plate, the effective field angle θ of the spot monitoring camera, and the target surface length D of the laser target plate is:

[0058] d ≥ D sinθ

[0059] Specifically, the power module includes a power supply 6 and a power supply mounting frame 7 , and the power supply 6 is fixedly mounted on the power supply mounting frame 7 , and the power supply mounting frame 7 is fixedly mounted on the system frame 8 .

[0060] Specifically, the power supply 6 is configured as a DC regulated power supply, which is interconnected with the spot monitoring camera 1 and the simulated target source 4 for power supply, and the power supply power and interface are matched with the two.

[0061] Specifically, the rotor UAV 9 is configured as a commercial low-altitude transport rotor UAV, the UAV air-lifting mechanism 10 is configured as a commercial external device matching the UAV model, and the payloads of the rotor UAV 9 and the UAV air-lifting mechanism 10 both match the total weight of the measurement system.

[0062] The present embodiment provides a method for rapid outfield measurement of laser irradiation accuracy, comprising the following steps:

[0063] Step 1: Start the power supply 6, power on the spot monitoring camera 1 and the simulated target source 4, adjust the angle of the camera mounting bracket 2, make the field center of the spot monitoring camera 1 face the crosshair center of the laser target plate 3, and start the automatic image recording and storage function of the spot monitoring camera 1;

[0064] Step 2: Take the position of the laser device to be tested as the take-off point, control the rotor UAV 9 to take off, fly to a suitable distance and then hover, adjust the attitude so that the laser target plate 3 faces the direction of the take-off point, record the vertical height H and horizontal distance S of the UAV relative to the take-off point at this moment through the operation interface of the rotor UAV 9, and calculate the slant distance L of the rotor UAV 9 relative to the take-off point:

[0065]

[0066] Step 3: The laser device to be tested emits light at the center of the two lamps of the simulated target source 4;

[0067] Step 4: After the laser stops emitting light, the rotor drone 9 is controlled to return home, and the laser spot image data recorded by the spot monitoring camera 1 is read;

[0068] Step 5: Calculate the energy centroid of the laser spot image. The calculation method is to perform a weighted average calculation of the energy of the pixel position coordinates, and then subtract the target plate crosshair center position coordinates to obtain the deviation of the spot centroid relative to the crosshair center:

[0069]

[0070]

[0071]

[0072] Among them, x k ,y k are the horizontal deviation and vertical deviation of the center of mass of the laser spot on the kth frame image relative to the center of the crosshairs of the target plate, respectively. i,j is the light intensity measurement value of the pixel in row i and column j, x i,j ,y i,j are the horizontal coordinate value and vertical coordinate value of the pixel in row i and column j, respectively. k is the total deviation.

[0073] Step 6: Divide the total deviation of the frame by the slant distance L to calculate the total deviation angle θ of the laser irradiation. k , which is the laser irradiation accuracy at that frame moment.

[0074]

[0075] Step 7: Repeat steps 5-6 to calculate the laser irradiation accuracy of all frame images. The change of laser irradiation accuracy over time can be obtained, and further statistical calculations can be performed as needed.

[0076] This embodiment provides a method for fast field measurement of laser irradiation accuracy for measuring a moving target, and the specific steps are as follows:

[0077] Step 1: Integrate a spot monitoring module and a target module on a hovering aircraft; the target module includes a laser target plate with a central crosshair and simulated target sources symmetrically arranged on both sides thereof;

[0078] Step 2: After aligning the field of view center of the spot monitoring module with the crosshair center of the laser target plate, start the automatic image recording and storage function of the spot monitoring module;

[0079] Step 3: Set the laser device to be tested as the take-off point of the hovering aircraft, control the hovering aircraft to fly according to the set trajectory, and make the laser target plate face the take-off direction, obtain the real-time height and horizontal distance of the flight relative to the take-off point, and calculate the actual slant distance of the hovering aircraft relative to the take-off point at different times;

[0080] Step 4: The laser device to be tested emits light at the center positions of two simulated target sources, and the laser spot image data is read by the spot monitoring module;

[0081] Step 5: Calculate the energy centroid of the laser spot image to obtain the total deviation of the laser spot centroid on the k-th frame image relative to the crosshair center of the target plate;

[0082] Step 6: Based on the total deviation of the laser spot mass center of the k-th frame image relative to the crosshair center of the target plate, calculate the total deviation angle of laser irradiation, which is the laser irradiation accuracy at the frame moment;

[0083] Step 7: Repeat the above steps until the laser irradiation accuracy of all frame images is completed.

[0084] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for rapid field measurement of laser irradiation accuracy, characterized in that The specific steps are as follows: The spot monitoring module and the target module are integrated on the hovering aircraft; the target module includes a laser target plate with a central cross line and simulated target sources symmetrically arranged on both sides thereof; After aligning the field of view center of the spot monitoring module with the crosshair center of the laser target plate, start the automatic image recording and storage function of the spot monitoring module; Set the laser device to be tested as the take-off point of the hovering aircraft, control the hovering aircraft to fly to the specified position, face the laser target plate to the take-off direction, obtain the height and horizontal distance relative to the take-off point, and calculate the actual slant distance of the hovering aircraft relative to the take-off point; The laser device to be tested uses the center positions of two simulated target sources as the target for light emission, and the laser spot image data is read by the spot monitoring module; The spot energy centroid is calculated for the laser spot image to obtain the total deviation of the laser spot centroid on the k-th frame image relative to the crosshair center of the target plate; Based on the total deviation of the mass center of the laser spot of the k-th frame image relative to the center of the crosshairs of the target plate, the total deviation angle of laser irradiation is calculated, which is the laser irradiation accuracy at the moment of the frame; Repeat the above steps until the laser irradiation accuracy of all frame images is completed.

2. According to claim 1, a method for rapid outfield measurement of laser irradiation accuracy is characterized by: The designated position is the position corresponding to the slant distance required by the irradiation distance index of the laser device to be measured.

3. The method for rapid outfield measurement of laser irradiation accuracy according to claim 1, characterized in that: The actual slant distance L of the hovering aircraft relative to the take-off point is calculated as follows: Wherein, H is the vertical height of the hovering aircraft relative to the take-off point, and S is the horizontal distance of the hovering aircraft relative to the take-off point.

4. The method for rapid outfield measurement of laser irradiation accuracy according to claim 1, characterized in that: The total deviation of the laser spot mass center on the k-th frame image relative to the target plate crosshair center is calculated as follows: Among them, x k ,y k are the horizontal deviation and vertical deviation of the center of mass of the laser spot on the kth frame image relative to the center of the crosshairs of the target plate, respectively. i,j is the light intensity measurement value of the pixel in row i and column j, x i,j ,y i,j are the horizontal coordinate value and vertical coordinate value of the pixel in row i and column j, respectively. k is the total deviation.

5. The method for rapid outfield measurement of laser irradiation accuracy according to claim 1, characterized in that: When calculating the total deviation, the energy of each pixel position of the image recorded by the light spot monitoring camera when no light is emitted needs to be deducted as the background to avoid interference from ambient stray light.

6. The method for rapid outfield measurement of laser irradiation accuracy according to claim 1, characterized in that: The total deviation angle θ of the laser irradiation k The calculation formula is:

7. A laser irradiation accuracy outfield rapid measurement system, used to implement the laser irradiation accuracy outfield rapid measurement method according to any one of claims 1 to 6; characterized in that: It includes a hovering aircraft and a system frame mounted thereon, wherein a spot monitoring module, a target module, and a power module are installed on the system frame; the spot monitoring module is arranged opposite to the target module, and is used to obtain and store the laser spot image data on the target module; the power module supplies power to the system equipment; The relationship between the installation distance d between the light spot monitoring module and the target module, the effective field angle θ of the light spot monitoring module, and the target surface length D of the laser target plate is: d≥D·sinθ.

8. The laser irradiation accuracy outfield rapid measurement system according to claim 7, characterized in that: The hovering aircraft is a rotary-wing UAV, which is connected to the system frame via a UAV aerial suspension mechanism.

9. The laser irradiation accuracy outfield rapid measurement system according to claim 7, characterized in that: The light spot monitoring module includes a light spot monitoring camera, which is fixed on the system frame through a camera mounting frame; the light spot monitoring camera is configured as an imaging detection camera with an automatic image recording and storage function, the imaging detection band matches the laser band to be tested, and the imaging detection field of view covers the target module; the camera mounting frame has a two-dimensional direction adjustment structure of azimuth and pitch.

10. A method for measuring a moving target using the laser irradiation accuracy external field rapid measurement system as claimed in claim 9, characterized in that The specific steps are as follows: The spot monitoring module and the target module are integrated on the hovering aircraft; the target module includes a laser target plate with a central cross line and simulated target sources symmetrically arranged on both sides thereof; After aligning the field of view center of the spot monitoring module with the crosshair center of the laser target plate, start the automatic image recording and storage function of the spot monitoring module; Set the laser device to be tested as the take-off point of the hovering aircraft, control the hovering aircraft to fly according to the set trajectory, and make the laser target plate face the take-off direction, obtain the real-time height and horizontal distance of the flight relative to the take-off point, and calculate the actual slant distance of the hovering aircraft relative to the take-off point at different times; The laser device to be tested uses the center positions of two simulated target sources as the target for light emission, and the laser spot image data is read by the spot monitoring module; The spot energy centroid is calculated for the laser spot image to obtain the total deviation of the laser spot centroid on the k-th frame image relative to the crosshair center of the target plate; Based on the total deviation of the mass center of the laser spot of the k-th frame image relative to the center of the crosshairs of the target plate, the total deviation angle of laser irradiation is calculated, which is the laser irradiation accuracy at the moment of the frame; Repeat the above steps until the laser irradiation accuracy of all frame images is completed.

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