Far field spot measurement system and method of measurement thereof

Abstract

The present application relates to the technical field of field spot measurement, and particularly relates to a far field spot measurement system and a measurement method thereof, the measurement system comprising: a transmitting end adjusting device and a receiving end adjusting device; the transmitting end adjusting device and the receiving end adjusting device are respectively arranged on two sides of a target to be measured; the first adjusting device is used for adjusting the position and height of a collimator lens barrel, so that the laser beam emitted by the laser is collimated by the collimator lens barrel and then is aligned with the target to be measured; the receiving end adjusting device is used for receiving the laser beam at the far field; a long-focus lens is connected with a second adjusting device, and the second adjusting device is used for adjusting the position and height of the long-focus lens, so that the long-focus lens receives and focuses the laser beam. The present application has the advantages that four-dimensional adjustment is realized through displacement turntables and adjusting feet, the change of the laser spot is monitored and analyzed in real time, the state of the laser is adjusted in real time, and the best spot image is collected by the high-speed camera.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of far-field light spot measurement, and in particular to a far-field light spot measurement system and a measurement method thereof. BACKGROUND

[0002] The far-field light spot measurement system is a technology for accurately measuring the intensity and spatial distribution of laser light spot under far-field conditions, which is crucial for analyzing the atmospheric transmission effect of high-power laser and evaluating the performance of laser systems. With the wide application of laser technology in the fields of laser communication, laser radar, laser ranging, etc., higher requirements are put forward for the measurement of laser performance parameters. The far-field light spot measurement system usually includes a diffuse reflection target plate, an optical lens, a CCD camera, a computer, image acquisition software and light spot analysis software, etc.

[0003] Although the existing far-field light spot measurement system plays an important role in the application of laser technology, it still has some shortcomings and limitations. First, the system error is relatively large. Since the main optical axis of the CCD camera lens and the normal line of the diffuse reflection target plate may not coincide, there is an included angle, which will cause system error. This error can be reduced by using a correction coefficient, but additional processing steps are still required. In addition, the non-uniformity of the response of a single pixel of the CCD detector to laser light will affect the measurement accuracy of the light spot centroid. In addition, during the light spot image acquisition and processing process, the system may be affected by noise, especially when the light spot image has uneven illumination or sudden noise, the traditional segmentation algorithm may not be able to accurately segment the light spot. SUMMARY

[0004] Therefore, the present application aims to provide a far-field light spot measurement system and a measurement method thereof, which can ensure that the main optical axis coincides with the normal line of the diffuse reflection by using the first adjusting device and the second adjusting device, and at the same time, a high-performance high-speed camera is equipped to perform correction.

[0005] To achieve the above object, the technical scheme of the present application is implemented as follows: a far-field light spot measurement system, comprising: a transmitting end adjusting device, a receiving end adjusting device and a computer; the transmitting end adjusting device and the receiving end adjusting device are respectively arranged on two sides of a target to be measured; the transmitting end adjusting device comprises a laser, a collimator lens barrel and a first adjusting device; the laser and the collimator lens barrel are arranged on the first adjusting device; the laser is connected with the collimator lens barrel through an optical fiber; the first adjusting device is configured to adjust the position of the collimator lens barrel in four degrees of freedom, so as to ensure that the laser beam emitted by the laser is adjusted and expanded in diameter by the collimator lens barrel and then irradiates onto the target to be measured; the receiving end adjusting device comprises a long-focus lens, a second adjusting device and a high-speed camera; the long-focus lens and the high-speed camera are arranged on the second adjusting device; the long-focus lens is located at a preset position in front of the high-speed camera and is used for receiving the laser beam at the far field; the second adjusting device is configured to adjust the position of the long-focus lens in four degrees of freedom, so as to ensure that the long-focus lens receives and focuses the laser beam to form a light spot image, and the high-speed camera collects the light spot image; the computer is used for calculating and analyzing the light spot image collected by the high-speed camera to obtain light spot data.

[0006] Further, the first adjusting device comprises a first displacement turntable, a first connecting plate, a first connecting seat, a second connecting seat and a laser fixing seat, the first connecting plate is arranged on the first displacement turntable, the first connecting seat, the second connecting seat and the laser fixing seat are arranged on the first connecting plate, and the laser is arranged on the laser fixing seat; the first connecting seat is used for fixing the front end of the collimator lens barrel, and the second connecting seat is used for fixing the tail end of the collimator lens barrel; the first displacement turntable adjusts the position of the first connecting plate, and then adjusts the position of the collimator lens barrel.

[0007] Further, the first adjusting device further comprises a first adjusting base plate and a first adjusting foot, the first displacement turntable and the first adjusting foot are arranged on the first adjusting base plate, and the first adjusting foot is used for adjusting the height of the first adjusting base plate, and then adjusting the height of the collimator lens barrel.

[0008] Further, the first connecting seat comprises a first support seat and a first compression ring; the first support seat comprises a first arc surface and a first connecting part, and the first compression ring comprises a second arc surface and a second connecting part; when the first connecting part and the second connecting part are connected, the first arc surface and the second arc surface form a first accommodating cavity, and the front end of the collimator lens barrel is located in the first accommodating cavity.

[0009] Further, the first connecting seat further comprises a first spring and a first gasket, and the first spring is located between the first connecting part and the second connecting part; the first gasket is arranged on the second arc surface.

[0010] Furthermore, the second adjustment device includes a second displacement turntable, a second connecting plate, a third connecting seat, and a fourth connecting seat; the second connecting plate is disposed on the second displacement turntable, and the third and fourth connecting seats are disposed on the second connecting plate; the third connecting seat is used to fix the tail end of the telephoto lens, and the fourth connecting seat is used to fix the front end of the telephoto lens; the second displacement turntable adjusts the position of the second connecting plate, thereby adjusting the position of the telephoto lens.

[0011] Furthermore, the second adjustment device also includes a second adjustment base plate and a second adjustment foot. The second displacement turntable and the second adjustment foot are both set on the second adjustment base plate. The second adjustment foot is used to adjust the height of the second adjustment base plate, thereby adjusting the height of the telephoto lens.

[0012] Furthermore, the third connecting seat includes a third support seat and a third pressure ring; the third support seat includes a third arc surface and a third connecting part, and the third pressure ring includes a fourth arc surface and a fourth connecting part; when the third connecting part is connected to the fourth connecting part, the third arc surface and the fourth arc surface form a third receiving cavity, and the tail end of the telephoto lens is located in the third receiving cavity.

[0013] Furthermore, the first connecting seat also includes a second spring and two second washers, with the second spring located between the third connecting part and the fourth connecting part; the two second washers are respectively disposed on the third arc surface and the fourth arc surface.

[0014] A far-field spot measurement method, implemented using the aforementioned far-field spot measurement system, includes the following steps:

[0015] S1: First, connect the laser and collimating lens tube to the first adjustment device, then connect the laser to the collimating lens tube through an optical fiber to form a transmitter adjustment device; at the same time, connect the telephoto lens and the high-speed camera to the second adjustment device, with the telephoto lens located at a preset position in front of the high-speed camera to form a receiver adjustment device.

[0016] S2: Set the transmitter adjustment device and the receiver adjustment device on both sides of the target to be measured.

[0017] S3: The laser is activated to emit a laser beam, which is transmitted through an optical fiber to the collimating lens tube. The collimating lens tube adjusts the laser beam and expands its diameter before illuminating the target to be measured.

[0018] S4: Adjust the pupils and optical axes of the collimating lens and telephoto lens respectively to ensure that the laser beam being measured is fully received by the telephoto lens, so that the far-field spot is located at the center of the high-speed camera target surface.

[0019] S5: The computer performs calculations and analysis on the spot images captured by the high-speed camera to obtain spot data.

[0020] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0021] 1) Four-dimensional adjustment is achieved through a displacement turntable and adjustable feet, real-time monitoring and analysis of changes in the laser spot are performed, and the working state of the laser is adjusted in an instant to ensure that the high-speed camera captures the best spot image.

[0022] 2) By setting up a first gasket and a second gasket made of polytetrafluoroethylene, as well as a first spring and a second spring, it is possible to press the straight lens barrel and the telephoto lens together without damaging the outer surface of the straight lens barrel and the telephoto lens.

[0023] 3) The far-field spot measurement system has sufficient rigidity and strength to ensure that the changes in the line of sight and the mirror surface are within the allowable range.

[0024] 4) This invention also has wide applicability, is compatible with a variety of laser types, covers a wide range from single pulse to several hundred hertz and below medium and high energy, and has good versatility and flexibility. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the structure of the far-field spot measurement system provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the transmitter adjustment device provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the first connecting seat provided according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the receiving end adjustment device provided according to an embodiment of the present invention;

[0030] Figure 5 This is a structural schematic diagram of the third connector provided according to an embodiment of the present invention.

[0031] The reference numerals in the accompanying drawings include: 1. Transmitter adjustment device; 11. Laser; 12. Collimating lens tube; 13. First adjustment device; 131. First adjustment base plate; 132. First adjustment foot; 133. First displacement turntable; 134. First connecting plate; 135. First connecting seat; 1351. First support seat; 1352. First pressure ring; 1353. First spring; 1354. First gasket; 1355. First arc surface; 1356. First connecting part; 1357. Second arc surface; 1358. Second connecting part; 136. Second connecting seat; 137. Laser 1. Receiver mounting base; 2. Receiver adjustment device; 21. Telephoto lens; 22. High-speed camera; 23. Second adjustment device; 231. Second adjustment base plate; 232. Second adjustment foot; 233. Second displacement turntable; 234. Second connecting plate; 235. Third connecting seat; 2351. Third support seat; 2352. Third pressure ring; 2353. Second spring; 2354. Second washer; 2355. Third arc surface; 2356. Third connecting part; 2357. Fourth arc surface; 2358. Fourth connecting part; 236. Fourth connecting seat; 3. Target to be measured. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] like Figure 1 As shown, an embodiment of the present invention provides a far-field spot measurement system, comprising: a transmitter adjustment device 1, a receiver adjustment device 2, and a computer; the transmitter adjustment device 1 and the receiver adjustment device 2 are respectively disposed on both sides of the target 3 to be measured. In this invention, the plane where the first connecting plate 134 is located is defined as the first XY plane. The plane where the second connecting plate 234 is located is defined as the second XY plane.

[0038] like Figure 2 As shown, the transmitting end adjustment device 1 includes a laser 11, a collimating lens tube 12, and a first adjustment device 13. The laser 11 is connected to the collimating lens tube 12 via an optical fiber. The collimating lens tube 12 is connected to the first adjustment device 13. The first adjustment device 13 is used to adjust the position of the collimating lens tube 12 on the first XY plane and the height of the collimating lens tube 12 on the first Z axis, ensuring that the laser beam emitted by the laser 11, after being adjusted and enlarged in diameter by the collimating lens tube 12, illuminates the target 3 to be measured. The first Z axis is perpendicular to the XY plane. The laser 11, the collimating lens tube 12, and the first adjustment device 13 together constitute the transmitting end.

[0039] In this embodiment, the laser 11 is a 532nm (±0.1 nm) solid-state laser manufactured by Changchun New Industries Optoelectronic Technology Co., Ltd.

[0040] The collimating lens tube 12 receives the laser beam emitted by the laser 11 and expands the diameter of the laser beam to the required aperture according to actual usage. The collimating lens tube 12 is a focalless system. The collimating lens tube 12 consists of two lenses: a negative power lens and a positive power lens. The collimating lens tube 12, composed of two lenses, is smaller and lighter. The rear surface of the first lens of the collimating lens tube 12 is aspherical, efficiently shaping the Gaussian light into a flat-top light, resulting in a uniform intensity distribution of the expanded laser beam. This not only improves the uniformity of the light spot but also significantly shortens the length of the collimating lens tube. In this embodiment, the operating wavelength of the collimating lens tube 12 is 532nm.

[0041] The first adjustment device 13 includes a first adjustment base plate 131, a first adjustment foot 132, a first displacement turntable 133, a first connecting plate 134, a first connecting seat 135, a second connecting seat 136, and a laser fixing seat 137.

[0042] The first adjustment base plate 131 is a rectangular plate made of aluminum alloy. The back of the first adjustment base plate 131 is treated with lightweight material. A first boss is provided on the upper surface of the first adjustment base plate 131 for mounting the first displacement turntable 133. The position of the first displacement turntable 133 is set according to the center of gravity of the transmitter adjustment device 1, and the center of gravity of the first displacement turntable 133 coincides with the center of gravity of the transmitter adjustment device 1.

[0043] The end of the first adjusting base plate 131 closest to the target to be tested is defined as the front end, and the end furthest from the target to be tested is defined as the rear end.

[0044] A first adjustment foot 132 is installed near each of the two corners of the front end of the first adjustment base plate 131, and a first adjustment foot 132 is installed at the middle position of the rear end of the first adjustment base plate 131. The first adjustment foot 132 is used to adjust the height of the first adjustment base plate 131, thereby adjusting the height of the collimating lens tube 12 in the first Z-axis direction.

[0045] The end of the collimating lens tube 12 closest to the target 3 is defined as the front end, and the end connected to the laser 11 is defined as the tail end.

[0046] A first connecting plate 134 is mounted on a first displacement turntable 133. A first connecting seat 135, a second connecting seat 136, and a laser mounting seat 137 are mounted on the first connecting plate 134. The first connecting seat 135 is used to fix the front end of the collimating lens tube 12, and the second connecting seat 136 is used to fix the rear end of the collimating lens tube 12. The laser mounting seat 137 is located between the first connecting seat 135 and the second connecting seat 136, and the laser 11 is mounted on the laser mounting seat 137.

[0047] The first displacement turntable 133 is configured to realize three translational degrees of freedom along the X, Y, and Z axes and one rotational degree of freedom along the Z axis in three-dimensional space.

[0048] The direction along which the first displacement stage 133 propagates the laser beam (i.e., the direction along the length of the first connecting seat 135) is defined as the first X-axis. The direction in which the first displacement stage 133 moves perpendicular to the direction of laser beam propagation but within the plane of the first connecting seat 135 (i.e., the direction of the width of the first connecting seat 135) is defined as the first Y-axis. The direction perpendicular to the plane defined by the first X-axis and the first Y-axis (i.e., the direction perpendicular to the plane where the first connecting seat 135 is located) is defined as the first Z-axis.

[0049] The first displacement turntable 133 adjusts the position of the collimating lens tube 12 in the first XY plane by adjusting the position of the first connecting plate 134 along the first X-axis and the first Y-axis and the rotation angle around the first Z-axis.

[0050] In this embodiment, the first displacement turntable 133 and the second displacement turntable 233 described below are purchased from Beijing Zhuoli Hanguang Instrument Co., Ltd., specifically model LSP125 or LD90, which will not be described in detail here.

[0051] like Figure 3 As shown, the first connecting seat 135 includes a first support seat 1351, a first pressure ring 1352, a first spring 1353, and a first gasket 1354. The first support seat 1351 includes a first arcuate surface 1355 and a first connecting portion 1356, and the first pressure ring 1352 includes a second arcuate surface 1357 and a second connecting portion 1358. When the first connecting portion 1356 is connected to the second connecting portion 1358, the first arcuate surface 1355 and the second arcuate surface 1357 form a first circular receiving cavity, which is adapted to the front end of the collimating lens tube 12, and the front end of the collimating lens tube 12 is located within the first circular receiving cavity.

[0052] A first gasket 1354 is disposed on a second arc surface 1357, and a first spring 1353 is located between a first connecting portion 1356 and a second connecting portion 1358. The first connecting portion 1356 and the second connecting portion 1358 are connected by bolts. The first gasket 1354 is made of polytetrafluoroethylene. By disposing of the first gasket 1354 on the second arc surface 1357 and the first spring 1353 between the first connecting portion 1356 and the second connecting portion 1358, it is possible to press the aligned straight lens barrel 12 tightly without damaging the outer surface of the aligned straight lens barrel 12, and quick assembly and disassembly can be achieved.

[0053] The second connecting seat 136 has a similar structure to the first connecting seat 135, including a second support seat and a second pressure ring. When the second support seat and the second pressure ring are connected, they form a second circular receiving cavity. The second circular receiving cavity is adapted to the tail end of the collimating lens tube 12, and the tail end of the collimating lens tube 12 is located in the second circular receiving cavity.

[0054] In this embodiment, the first adjustment device 13 further includes a dust cover, which is disposed on the first connecting plate 134. The dust cover has a round hole on the side near the front end of the collimating lens tube 12 for the laser beam to pass through.

[0055] The direction along which the second displacement stage 233 propagates the laser beam (i.e., the direction along the length of the third connecting seat 235) is defined as the second X-axis. The direction in which the second displacement stage 233 moves perpendicular to the direction of laser beam propagation but within the plane of the third connecting seat 235 (i.e., the direction of the width of the third connecting seat 235) is defined as the second Y-axis. The direction perpendicular to the plane defined by the second X-axis and the second Y-axis (i.e., the direction perpendicular to the plane where the third connecting seat 235 is located) is defined as the second Z-axis.

[0056] like Figure 4 As shown, the receiver adjustment device 2 includes a telephoto lens 21, a high-speed camera 22, and a second adjustment device 23. The telephoto lens 21 is located at a preset position directly in front of the high-speed camera 22 and is used to receive the laser beam from the far field. The telephoto lens 21 is connected to the second adjustment device 23, which is used to adjust the position of the telephoto lens 21 in the second XY plane and the height of the telephoto lens 21 in the second Z-axis direction to ensure that the telephoto lens 21 receives and focuses the laser beam. The high-speed camera 22 acquires the image of the light spot formed by the laser beam illuminating the target 3 under test. The telephoto lens 21, the high-speed camera 22, and the second adjustment device 23 together constitute the receiver.

[0057] The telephoto lens 21 operates at a wavelength of 532nm and includes a lens group consisting of two lenses, a reflecting mirror, a secondary mirror, and a primary mirror.

[0058] The high-speed camera 22 is connected to the second connecting plate 234 via an adjusting base. The adjusting base allows for displacement in three directions. The structure of the adjusting base is not described in detail here; it is sufficient that it enables the high-speed camera 22 to be adjusted in three directions. The high-speed camera is an externally purchased component, model MEMRECAM ACS-1 M40.

[0059] The second adjustment device 23 includes a second adjustment base plate 231, a second adjustment foot 232, a second displacement turntable 233, a second connecting plate 234, a third connecting seat 235, and a fourth connecting seat 236.

[0060] The second adjustment base plate 231 is a rectangular plate made of aluminum alloy. The back of the second adjustment base plate 231 adopts a lightweight design. A second boss is provided on the upper surface of the second adjustment base plate 231 for mounting the second displacement turntable 233. The position of the second displacement turntable 233 is set according to the center of gravity of the transmitting end adjustment device 1, and the center of gravity of the second displacement turntable 233 coincides with the center of gravity of the receiving end adjustment device 2. A second adjustment foot 232 is installed near each of the two corners of the second adjustment base plate 231 on the side closer to the target 3, and a second adjustment foot 232 is installed at the middle position on the side of the second adjustment base plate 231 away from the target 3. The second adjustment feet 232 are used to adjust the height of the second adjustment base plate 231, thereby adjusting the height of the telephoto lens 21 in the second Z-axis direction.

[0061] In this embodiment, the end of the telephoto lens 21 closer to the high-speed camera 22 is defined as the tail end, and the end of the telephoto lens 21 farther away from the high-speed camera 22 is defined as the front end.

[0062] The second connecting plate 234 is mounted on the second displacement turntable 233, and the third connecting seat 235 and the fourth connecting seat 236 are mounted on the second connecting plate 234. The third connecting seat 235 is used to fix the tail end of the telephoto lens 21, and the fourth connecting seat 236 is used to fix the front end of the telephoto lens 21. The second displacement turntable 233 adjusts the position of the second connecting plate 234 along the second X-axis and the second Y-axis, as well as the rotation angle around the second Z-axis, thereby adjusting the position of the telephoto lens 21 in the second XY plane.

[0063] like Figure 5 As shown, the third connecting seat 235 includes a third support seat 2351, a third pressure ring 2352, a second spring 2353, and two second washers 2354.

[0064] The third support 2351 includes a third arc surface 2355 and a third connecting portion 2356, and the third pressure ring 2352 includes a fourth arc surface 2357 and a fourth connecting portion 2358. When the third connecting portion 2356 is connected to the fourth connecting portion 2358, the third arc surface 2355 and the fourth arc surface 2357 form a third circular receiving cavity, which is adapted to the tail end of the telephoto lens 21, and the tail end of the telephoto lens 21 is located inside the third circular receiving cavity.

[0065] Two second washers 2354 are respectively disposed on the third arc surface 2355 and the fourth arc surface 2357. The second spring 2353 is located between the third connecting part 2356 and the fourth connecting part 2358, which are connected by bolts. Both second washers 2354 are made of polytetrafluoroethylene. By disposing of the second washers 2354 on the third arc surface 2355 and the fourth arc surface 2357, and by disposing of the second spring 2353 between the third connecting part 2356 and the fourth connecting part 2358, the telephoto lens 21 can be pressed firmly without damaging its outer surface, and quick assembly and disassembly can be achieved.

[0066] The fourth connector 236 has a similar structure to the third connector 235, including a fourth support and a fourth pressure ring. When the fourth support and the fourth pressure ring are connected, they form a fourth circular receiving cavity. The fourth circular receiving cavity is adapted to the front end of the telephoto lens 21, and the front end of the telephoto lens 21 is located in the fourth circular receiving cavity.

[0067] At the transmitting end, laser 11 emits a laser beam, which is transmitted through an optical fiber to collimating lens 12. Collimating lens 12 adjusts and enlarges the diameter of the laser beam before it illuminates the target 3. At the receiving end, telephoto lens 21 receives the laser beam from the target 3 and focuses it onto the target surface of high-speed camera 22, forming a light spot. High-speed camera 22 acquires and records the light spot image information. A computer performs calculations and analysis on the light spot image acquired by high-speed camera 22 to obtain light spot data.

[0068] To ensure the far-field spot measurement system possesses sufficient rigidity and strength, and exhibits good dimensional stability under harsh temperature conditions to guarantee that changes in the line of sight and mirror surface remain within acceptable limits, a comprehensive engineering analysis of its optomechanical structure was conducted. This analysis examined the rigidity feasibility of the far-field spot measurement system, including its static and dynamic stiffness, as well as its resistance to mechanical vibration interference during transmission and space operation. The engineering analysis employed NX modeling and NX / Nastran solving, demonstrating that the far-field spot measurement system is structurally stable and reliable.

[0069] A far-field spot measurement method, implemented using the aforementioned far-field spot measurement system, includes the following steps:

[0070] S1: First, connect the laser 11 and the collimating lens tube 12 to the first adjustment device 13 respectively. Then, connect the laser 11 to the collimating lens tube 12 through an optical fiber to form the transmitter adjustment device 1. At the same time, connect the telephoto lens 21 and the high-speed camera 22 to the second adjustment device 23 respectively. The telephoto lens 21 is located at a preset position directly in front of the high-speed camera 22 to form the receiver adjustment device 2.

[0071] S2: The transmitter adjustment device 1 and the receiver adjustment device 2 are respectively set on both sides of the target to be measured 3.

[0072] S3: Start the laser 11. The laser 11 emits a laser beam, which is transmitted to the collimating lens tube 12 through the optical fiber. The collimating lens tube 12 adjusts the laser beam and expands its diameter before illuminating the target 3 to be tested.

[0073] S4: Adjust the pupil and optical axis of the collimating lens tube 12 and the telephoto lens 21 respectively to ensure that the laser beam under test is fully received by the telephoto lens 21, so that the far-field spot is located at the center of the target surface of the high-speed camera 22.

[0074] The pupils and optical axes of the collimating lens 12 and the telephoto lens 21 are adjusted by the first displacement turntable 133 and the second displacement turntable 233, respectively.

[0075] S5: The computer performs calculations and analysis on the spot images acquired by the high-speed camera 22 to obtain spot data.

[0076] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A far field spot measurement system characterized by, The application relates to a laser beam diameter adjustment device, which comprises a transmitting end adjusting device, a receiving end adjusting device and a computer; the transmitting end adjusting device and the receiving end adjusting device are arranged on the two sides of a target to be measured respectively; the transmitting end adjusting device comprises a laser, a collimating lens barrel and a first adjusting device; the laser and the collimating lens barrel are arranged on the first adjusting device; the laser is connected with the collimating lens barrel through an optical fiber; the first adjusting device is configured to adjust the position of the collimating lens barrel in four degrees of freedom, so that the laser beam emitted by the laser is adjusted and expanded in diameter through the collimating lens barrel and then irradiated onto the target to be measured; the receiving end adjusting device comprises a long-focus lens, a second adjusting device and a high-speed camera; the long-focus lens and the high-speed camera are arranged on the second adjusting device; the long-focus lens is located at a preset position in front of the high-speed camera and is used for receiving the laser beam at a far field; the second adjusting device is configured to adjust the position of the long-focus lens in four degrees of freedom, so that the long-focus lens receives and focuses the laser beam to form a light spot image, and the high-speed camera collects the light spot image; the first adjusting device comprises a first displacement turntable, a first connecting plate, a first connecting seat, a second connecting seat and a laser fixing seat; the first connecting plate is arranged on the first displacement turntable; the first connecting seat, the second connecting seat and the laser fixing seat are arranged on the first connecting plate; the laser is arranged on the laser fixing seat; the first connecting seat is used for fixing the front end of the collimating lens barrel; the second connecting seat is used for fixing the tail end of the collimating lens barrel; the first displacement turntable adjusts the position of the first connecting plate and then adjusts the position of the collimating lens barrel; the first displacement turntable is configured to realize the movement of three translation degrees of freedom along X, Y and Z axes and one rotation degree of freedom around the Z axis in a three-dimensional space; the second adjusting device comprises a second displacement turntable, a second connecting plate, a third connecting seat and a fourth connecting seat; the second connecting plate is arranged on the second displacement turntable; the third connecting seat and the fourth connecting seat are arranged on the second connecting plate; the third connecting seat is used for fixing the tail end of the long-focus lens; the fourth connecting seat is used for fixing the front end of the long-focus lens; the second displacement turntable adjusts the position of the second connecting plate and then adjusts the position of the long-focus lens; the second displacement turntable adjusts the position of the second connecting plate along a second X axis direction and a second Y axis direction and a rotation angle around a second Z axis, and then adjusts the position of the long-focus lens in a second XY plane; the computer is used for calculating and analyzing the light spot image collected by the high-speed camera and obtaining light spot data. The first adjusting device further comprises a first adjusting base plate and a first adjusting foot; the first displacement turntable and the first adjusting foot are arranged on the first adjusting base plate; the first adjusting foot is used for adjusting the height of the first adjusting base plate and then adjusting the height of the collimating lens barrel. ​ ​ ​ ​ ​ ​ ​ ​ 2. The far field spot measurement system of claim 1, wherein, ​ 3. The far field spot measurement system of claim 1, wherein, The first connecting seat comprises a first support seat and a first compression ring; the first support seat comprises a first arc surface and a first connecting part, and the first compression ring comprises a second arc surface and a second connecting part; when the first connecting part is connected with the second connecting part, the first arc surface and the second arc surface form a first accommodating cavity, and the front end of the collimator barrel is located in the first accommodating cavity.

4. The far field spot measurement system of claim 3, wherein, The first connecting seat further comprises a first spring and a first gasket; the first spring is located between the first connecting part and the second connecting part; and the first gasket is arranged on the second arc surface.

5. The far field spot measurement system of claim 1, wherein, The second adjusting device further comprises a second adjusting base plate and a second adjusting foot; the second displacement turntable and the second adjusting foot are arranged on the second adjusting base plate; and the second adjusting foot is used for adjusting the height of the second adjusting base plate, so as to adjust the height of the long-focus lens.

6. The far field spot measurement system of claim 1, wherein, The third connecting seat comprises a third support seat and a third compression ring; the third support seat comprises a third arc surface and a third connecting part, and the third compression ring comprises a fourth arc surface and a fourth connecting part; when the third connecting part is connected with the fourth connecting part, the third arc surface and the fourth arc surface form a third accommodating cavity, and the tail end of the long-focus lens is located in the third accommodating cavity.

7. The far field spot measurement system of claim 6, wherein, The first connecting seat further comprises a second spring and two second gaskets; the second spring is located between the third connecting part and the fourth connecting part; and the two second gaskets are arranged on the third arc surface and the fourth arc surface respectively.

8. A method of far field spot measurement, implemented by using the far field spot measurement system according to any one of claims 1-7, characterized in that, The method comprises the following steps: S1: first, connect the laser and the collimator barrel with the first adjusting device respectively, then connect the laser with the collimator barrel through an optical fiber, to form a transmitting end adjusting device; at the same time, connect the long-focus lens and the high-speed camera with the second adjusting device respectively, and the long-focus lens is located at a preset position in front of the high-speed camera, to form a receiving end adjusting device; S2: arrange the transmitting end adjusting device and the receiving end adjusting device on two sides of a target to be measured respectively; S3: start the laser, the laser emits a laser beam, the laser beam is transmitted to the collimator barrel through the optical fiber, the collimator barrel adjusts and enlarges the diameter of the laser beam, and then irradiates the target to be measured; S4: adjust the pupils and optical axes of the collimator barrel and the long-focus lens respectively, to ensure that the measured laser beam is completely received by the long-focus lens, and the far-field spot is located at the center of the target surface of the high-speed camera; S5: the computer performs calculation and analysis on the spot image collected by the high-speed camera, to obtain spot data.

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