Moving target measurement optical system and measurement method

Abstract

The invention belongs to an optical system, and provides a moving target measurement optical system and a measurement method, aiming at the technical problems that when the track of an aerial target is measured at present, only intersection measurement can be carried out, and distance measurement cannot be carried out by a single theodolite, so that measurement is inconvenient and calculation is complex. Comprising a main optical system, a laser ranging receiving correction lens group, a visible light collimating lens group, a visible light imaging lens group and a medium-wave infrared projection lens group. A laser ranging receiving light path, visible light measurement and infrared measurement common aperture structural form is adopted, single-station simultaneous angle measurement, ranging and temperature distribution measurement are achieved, and then single-station moving target track measurement is completed. Visible light imaging, medium-wave infrared capture measurement and laser ranging receiving share a primary mirror and a secondary mirror of the Cassegrain mirror group, high-resolution imaging, high-precision angle measurement and laser ranging are realized without parallax and optical axis sharing, and the requirements of long-focus high-definition imaging, long-distance high-precision angle measurement and long-distance ranging can be met at the same time.

Description

Technical Field

[0001] The present application relates to an optical system, and more particularly to a moving target measurement optical system and a measurement method. Background Art

[0002] The photoelectric theodolite is a large optical measuring device for automatic tracking and measurement of moving targets. It is suitable for trajectory measurement of moving targets with long aerial trajectories and can obtain reliable and accurate position and velocity parameters.

[0003] At present, when photoelectric theodolites perform high-precision measurements on moving targets, two or more photoelectric theodolites are distributed at a certain distance and at a certain angle to the target, and then their measurement data are combined to jointly solve the position information (angle and distance) of the target in the air to achieve the purpose of tracking measurement. This is also the principle of intersection measurement of photoelectric theodolites. A single theodolite can only measure the elevation and pitch angles of a target, so a single theodolite cannot measure the trajectory of an aerial target. Summary of the invention

[0004] The present application aims to provide an optical system and a method for measuring a moving target, in order to solve the technical problem that, when measuring the trajectory of an aerial target, only intersection measurement can be performed, and a single theodolite cannot perform distance measurement, resulting in inconvenient measurement and complex calculation.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions: In a first aspect, the present application proposes a moving target measurement optical system, including a main optical system, a laser ranging receiving and correction lens group, a visible light collimating lens group, a visible light imaging lens group and a medium-wave infrared projection lens group; The primary optical system comprises a Cassegrain mirror group and a spectral beam splitter; light incident parallel to the optical axis is incident from the primary mirror of the Cassegrain mirror group; the spectral beam splitter is located in front of the primary image of the secondary mirror of the Cassegrain mirror group, so as to reflect the visible light path and transmit the laser light path; After the laser light path is incident on the laser ranging receiving and correction lens group, it converges to the detector target surface and is used to calculate the distance from the moving target to the measuring optical system; After the visible light path is incident on the visible light collimating lens group, the visible light path is turned to be parallel to the optical axis, and the visible light path is located in the second layer above the optical axis; The visible light path on the second layer is incident on the visible light imaging lens group and then converges to the camera target surface, which is used to identify and track the moving target, determine the angle between the moving target and the visual axis of the measuring optical system, and determine the position of the target in two-dimensional space in combination with the distance from the moving target to the measuring optical system; The mid-wave infrared light path transmitted through the secondary mirror of the Cassegrain mirror set is parallel to the optical axis after being turned and is located in the second layer above the optical axis; The medium-wave infrared light path located on the second layer is incident on the medium-wave infrared projection lens group and then imaged on the target surface of the thermal imager, which is used to capture and track the target and determine the temperature distribution of the moving target.

[0006] Furthermore, the main optical system further comprises a first folding axis reflector and a second folding axis reflector; The medium-wave infrared light path transmitted through the secondary mirror of the Cassegrain mirror assembly is parallel to the optical axis after being deflected by the first folding axis reflector and the second folding axis reflector in sequence.

[0007] Furthermore, the laser ranging receiving correction lens group includes a plane correction plate, a positive focal length curved image plane lens and a first positive focal length biconvex lens arranged in sequence along the laser light path; the laser light path compensates for the astigmatism introduced by the spectral beam splitter through the plane correction plate, and converges through the positive focal length curved image plane lens and the positive focal length biconvex lens in sequence.

[0008] Further, the visible light collimating lens group includes a second positive power biconvex lens, a first meniscus lens, a negative power biconcave lens, a negative power cemented lens, a second meniscus lens and a third folding axis reflector, which are sequentially arranged along the visible light path; The first meniscus lens is a meniscus lens with positive optical power that bends toward a parallel optical path, and the second meniscus lens is a meniscus lens that bends toward a primary image plane.

[0009] Further, the visible light imaging lens group includes a third meniscus lens, a fourth meniscus lens, a third positive focal length biconvex lens, a negative focal length biconcave lens, a fifth meniscus lens and a sixth meniscus lens, which are sequentially arranged along the visible light path located on the second layer; The third meniscus lens is a positive focal meniscus lens bent toward the image side, the fourth meniscus lens is a negative focal meniscus lens bent toward the image side, the fifth meniscus lens is a positive focal meniscus lens bent toward the image side, and the sixth meniscus lens is a positive focal meniscus lens bent toward the image side.

[0010] Furthermore, the medium-wave infrared projection lens assembly includes a first silicon lens, a negative optical focal length biconcave germanium lens, a positive optical focal length zinc sulfide lens bent toward the image plane, and a second silicon lens with positive optical focal length bent toward the image plane, which are sequentially arranged along the medium-wave infrared optical path located on the second layer.

[0011] Further, the primary mirror of the Cassegrain mirror assembly is a concave parabolic mirror, the secondary mirror of the Cassegrain mirror assembly is a convex hyperbolic spectral beam splitting secondary mirror, and the surface type of at least one of the first positive power biconvex lens, the fourth meniscus lens, and the negative power biconcave lens is aspherical; The calculation method of the vector height of paraboloids, hyperboloids and aspherical surfaces includes:

[0012] in, Indicates the height of the arrow. represents the curvature, r represents the radius of the ring, represents the coefficient of the quadratic term, represents the 4th-order aspheric coefficient, represents the sixth-order aspheric coefficient, represents the 8th-order aspheric coefficient, Indicates the 10th-order aspheric coefficient.

[0013] Furthermore, the focal length of the visible light imaging system where the camera target surface is located is 4500 mm, and the F number is 10; The focal length of the medium-wave infrared measurement system where the thermal imager target surface is located is 900 mm, and the F number is 2; The receiving focal length of the laser rangefinder where the detector target surface is located is 550mm.

[0014] In a second aspect, the present application proposes a moving target measurement method, based on the above-mentioned moving target measurement optical system, comprising: The laser beam and visible light are respectively irradiated onto the moving target, and the reflected laser beam and visible light are incident on the primary mirror of the Cassegrain mirror group; And the medium-wave infrared radiation emitted by the moving target is incident on the main mirror of the Cassegrain mirror group.

[0015] Furthermore, it also includes: Calculate the distance from the moving target to the measuring optical system based on the laser signal in the laser light path converged by the detector target surface; Obtain a visible light image based on the visible light path converged by the camera target surface, identify and track the moving target, determine the angle between the moving target and the visual axis of the measuring optical system, and determine the position of the target in two-dimensional space in combination with the distance from the moving target to the measuring optical system; The medium-wave infrared image is obtained according to the medium-wave infrared light path converged by the target surface of the thermal imager to capture and track the target and determine the temperature distribution of the moving target.

[0016] Compared with the prior art, this application has the following beneficial effects: The present application proposes an optical system for measuring moving targets, including a main optical system, a laser ranging receiving correction lens group, a visible light collimating lens group, a visible light imaging lens group and a medium-wave infrared projection lens group, and adopts a structure of a common aperture for laser ranging receiving optical path, visible light measurement and infrared measurement to achieve single-station simultaneous angle measurement, distance measurement and temperature distribution measurement, and thus complete the single-station moving target trajectory measurement. Visible light imaging, medium-wave infrared capture measurement and laser ranging reception share the main mirror and secondary mirror of the Cassegrain lens group to achieve high-resolution imaging, high-precision angle measurement, and laser ranging without parallax common optical axis, which can simultaneously meet the needs of long-focus high-definition imaging, long-distance high-precision angle measurement and long-distance distance measurement. The entire system has a compact structure, good imaging quality, high energy concentration, simple structure and high stability.

[0017] The present application also proposes a moving target measurement method, which has all the advantages of the above-mentioned moving target measurement optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of an embodiment of the optical system for measuring a moving target of the present application; Figure 2 This is an MTF curve diagram of the visible light imaging optical system with a spatial frequency of 50lp / mm in the embodiment of the present application; Figure 3 This is a point diagram of the visible light imaging optical system in the embodiment of the present application; Figure 4 This is an MTF curve diagram of the medium-wave infrared measurement optical system with a spatial frequency of 33lp / mm in the embodiment of the present application; Figure 5 It is a point diagram of the medium-wave infrared measurement optical system in the embodiment of the present application; Figure 6 This is a graph of the enclosing circle energy of the laser ranging receiving optical system in the embodiment of the present application.

[0020] Wherein: 1-primary mirror, 2-secondary mirror, 3-spectral spectrometer, 4-first folding axis reflector, 5-second folding axis reflector, 6-plane correction plate, 7-positive focal length curved image lens, 8-first positive focal length biconvex lens, 9-second positive focal length biconvex lens, 10-first meniscus lens, 11-first negative focal length biconcave lens, 12-negative focal length cemented mirror, 13-second meniscus lens, 14-third folding axis reflector, 15-third meniscus lens, 16-fourth meniscus lens, 17-third positive focal length biconvex lens, 18-second negative focal length biconcave lens, 19-fifth meniscus lens, 20-sixth meniscus lens, 21-first silicon lens, 22-biconcave germanium lens, 23-zinc sulfide lens, 24-second silicon lens. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0023] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0024] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0025] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] As a high-precision optical measurement device, the photoelectric theodolite plays an important role in the fields of aviation, aerospace, astronomical observation, etc. Due to the limitations of its measurement principle, a single theodolite can only measure the elevation and pitch angles of the target, but cannot directly measure the actual distance from the moving target to the theodolite. Therefore, if you only rely on the data of a single theodolite, you cannot accurately depict the motion trajectory of the aerial target, because the lack of distance information will lead to inaccurate position calculation. In order to solve this problem, the intersection measurement technology of the photoelectric theodolite came into being. The intersection measurement principle of the photoelectric theodolite is based on the collaborative work of multiple theodolites. By observing the same moving target from multiple angles and directions, the precise position information of the target in the air can be comprehensively solved.

[0028] However, the existing intersection measurement method has the following defects: (1) High computational complexity. Intersection measurement usually requires the simultaneous establishment of multiple equations to solve the position information of the moving target, which involves complex mathematical calculations and data processing. As the number of measurement points increases and the measurement accuracy improves, the amount of calculation will increase significantly.

[0029] (2) High error accumulation. The error of each measuring device may affect the final result. Since the measurement data of multiple devices need to be integrated, these errors may accumulate with each other, resulting in a decrease in the accuracy of the final result.

[0030] (3) There are many restrictions on station layout. The accuracy and reliability of intersection measurement will be affected by the location of the measurement equipment. If the location of the station is unreasonable, it may lead to an increase in measurement errors or even make it impossible to perform effective intersection measurement.

[0031] (4) High data synchronization requirements. In intersection measurement, it is necessary to ensure that the data of multiple measurement devices are synchronized in time. If there is a problem with data synchronization, it may lead to increased errors in the measurement results, or even make it impossible to perform effective intersection measurement.

[0032] Based on the above-mentioned problems existing in single theodolite measurement and intersection measurement, the present application proposes an optical system and a measurement method for moving target measurement, which will be described in detail below in conjunction with embodiments and drawings.

[0033] As an embodiment of the moving target measurement optical system of the present application, it can include a main optical system, a laser ranging receiving and correction lens group, a visible light collimating lens group, a visible light imaging lens group and a medium-wave infrared projection lens group.

[0034] The main optical system includes a Cassegrain mirror group and a spectral beam splitter 3; the light incident parallel to the optical axis is incident from the primary mirror 1 of the Cassegrain mirror group; the spectral beam splitter 3 is located in front of the primary image of the secondary mirror 2 of the Cassegrain mirror group, so that the visible light path is reflected and the laser light path is transmitted. It should be noted that the working principle of the Cassegrain mirror group is that the light incident parallel to the optical axis is first reflected by the concave parabolic primary mirror 1 and converged to a focus, which is also a focus of the convex hyperbolic secondary mirror 2. Then, the secondary mirror 2 reflects these light rays to another focus, which is the Cassegrain focus, where the observer or imaging device can receive the light. The spectral beam splitter 3 is located in front of the primary image of the secondary mirror 2 of the Cassegrain mirror group, and its function is to selectively reflect the visible light path and transmit the laser light path. In this way, visible light and laser can be processed separately in the same optical system.

[0035] After the laser light path is incident on the laser ranging receiving and correcting lens group, it converges to the detector target surface, which is used to calculate the distance from the moving target to the measuring optical system. The laser ranging receiving and correcting lens group can correct and focus the laser light path, and finally converge it to the detector target surface. The detector calculates the distance from the moving target to the measuring optical system based on the received laser signal.

[0036] After the visible light path is incident on the visible light collimator lens group, the visible light path is turned to be parallel to the optical axis, and the visible light path is located in the second layer above the optical axis. After the visible light path located in the second layer is incident on the visible light imaging lens group, it converges to the camera target surface, which is used to identify and track the moving target, determine the visual axis angle between the moving target and the measuring optical system, and determine the position of the target in two-dimensional space in combination with the distance from the moving target to the measuring optical system. The visible light collimator lens group turns the visible light path to be parallel to the optical axis, and makes the visible light path located in the second layer above the optical axis. This design can separate the visible light path from the laser light path and the medium-wave infrared light path in space to avoid mutual interference. The visible light imaging lens group focuses the visible light path and finally converges it to the camera target surface. The camera can analyze the image content in real time, identify and track the moving target. By analyzing the position and size of the target in the image, the camera can determine the visual axis angle between the moving target and the measuring optical system. Combined with the distance from the moving target to the measuring optical system measured by the laser rangefinder receiving correction lens group, the camera can calculate the position of the target in two-dimensional space. .

[0037] The medium-wave infrared light path transmitted by the secondary mirror 2 of the Cassegrain lens group is parallel to the optical axis after turning, and is located in the second layer above the optical axis; the medium-wave infrared light path located in the second layer is incident on the medium-wave infrared projection lens group, and is imaged on the target surface of the thermal imager, which is used to capture and track targets and determine the temperature distribution of moving targets. The medium-wave infrared projection lens group images the medium-wave infrared light path and finally images it on the target surface of the thermal imager. Using the image processing algorithm, the thermal imager can analyze the image content in real time, identify and track moving targets. Different colors in the infrared thermal image represent different temperatures of the object being measured. By analyzing the color distribution of the target in the image, the thermal imager can determine the temperature distribution of the moving target.

[0038] The working principle of the above-mentioned moving target measurement optical system is: (1) Distance measurement: The laser transmitter emits a laser beam and irradiates the moving target. The reflected laser beam passes through the Cassegrain mirror group and the spectral beam splitter 3, and then enters the laser ranging receiving and correction mirror group. The laser ranging receiving and correction mirror group focuses the laser beam onto the detector target surface, and the detector calculates the distance from the moving target to the measuring optical system based on the received laser signal.

[0039] (2) Two-dimensional spatial position recognition and tracking: The visible light emitted by the visible light source (such as sunlight or artificial light source) irradiates the moving target, and the reflected visible light passes through the Cassegrain lens group and the spectral beam splitter 3, and then enters the visible light collimating lens group and the visible light imaging lens group. The visible light imaging lens group focuses the visible light onto the camera target surface. The camera recognizes and tracks the moving target based on the received visible light image, and the distance from the moving target to the measuring optical system measured by the laser ranging receiving and correcting lens group can be combined to calculate the position of the target in two-dimensional space.

[0040] (3) Determination of temperature distribution: The medium-wave infrared radiation emitted by the moving target is transmitted by the Cassegrain lens group and then incident on the medium-wave infrared projection lens group. The projection lens group images the medium-wave infrared radiation onto the target surface of the thermal imager. The thermal imager analyzes the image content in real time based on the received medium-wave infrared image, identifies and tracks the moving target, and determines the temperature distribution of the moving target.

[0041] Therefore, the moving target measurement optical system of the present application realizes the comprehensive measurement and analysis of moving targets by a single machine by integrating multiple technical means such as laser ranging, visible light imaging and medium-wave infrared imaging. It has the advantages of high precision, high reliability and real-time performance, and has broad application prospects in scientific research, industry and other fields.

[0042] like Figure 1 As shown, another embodiment of the moving target measurement optical system of the present application may include a main optical system, a laser ranging receiving and correction lens group, a visible light collimating lens group, a visible light imaging lens group, and a medium-wave infrared projection lens group. An optical system with a common aperture for laser ranging, visible light, and infrared measurement is realized.

[0043] The main optical system is composed of a primary mirror 1 of a concave parabolic Cassegrain mirror group, a secondary mirror 2 of a convex hyperbolic spectral Cassegrain mirror group, a spectral beam splitter 3, a first folding axis reflector 4 and a second folding axis reflector 5. For the laser ranging receiving optical path and the visible light measurement optical path, the secondary mirror 2 is a reflector, and for the infrared measurement optical path, the secondary mirror 2 is a lens.

[0044] The laser distance measurement receiving correction lens group is composed of a plane correction plate 6, a positive focal power bending image plane lens 7 and a first positive focal power biconvex lens 8. In this embodiment, the positive focal power bending image plane lens 7 is a H-ZF52 lens, and the first positive focal power biconvex lens 8 is a H-ZF52 lens. The visible light collimating lens group is composed of a second positive power biconvex lens 9, a first meniscus lens 10, a first negative power biconcave lens 11, a negative power cemented lens 12, a second meniscus lens 13 and a third folding axis reflector 14. In this embodiment, the second positive power biconvex lens 9 adopts an H-ZF88 lens, the first meniscus lens 10 adopts a meniscus H-LAF1 lens with positive power bent toward a parallel light path, the first negative power biconcave lens 11 adopts an H-ZF88 lens, the negative power cemented lens 12 adopts an H-LAF1 lens or an H-ZF13 lens, and the second meniscus lens 13 adopts a meniscus H-ZF88 lens bent toward a primary image plane.

[0045] The visible light imaging lens group is composed of a third meniscus lens 15, a fourth meniscus lens 16, a third positive focal power biconvex lens 17, a second negative focal power biconcave lens 18, a fifth meniscus lens 19 and a sixth meniscus lens 20. In this embodiment, the third meniscus lens 15 adopts a positive focal power HZF6 meniscus lens bent toward the image side, the fourth meniscus lens 16 adopts a negative focal power HLAF4 meniscus lens bent toward the image side, the third positive focal power biconvex lens 17 adopts a HQK3 lens, the second negative focal power biconcave lens 18 adopts a HLAF4 lens, the fifth meniscus lens 19 adopts a positive focal power HQK3 meniscus lens bent toward the image side, and the sixth meniscus lens 20 adopts a positive focal power HZF6 meniscus lens bent toward the image side.

[0046] The medium-wave infrared projection lens group is composed of a first silicon lens 21, a negative optical power biconcave germanium lens 22, a positive optical power zinc sulfide lens 23 bent toward the image plane, and a second silicon lens 24 bent toward the image plane. In this embodiment, the first silicon lens 21 is a positive optical power silicon lens bent toward the image plane.

[0047] As an example, in this embodiment, the interval between the primary mirror 1 and the secondary mirror 2 in the primary optical system is 833.3 mm, the interval between the reflection surface of the secondary mirror 2 and the spectrum beam splitter 3 is 600 mm, the interval between the transmission surface of the secondary mirror 2 and the first folding axis reflector 4 is 100 mm, and the interval between the first folding axis reflector 4 and the second folding axis reflector 5 is 540 mm. The interval between the rear surface of the spectrum beam splitter 3 and the laser ranging receiving correction mirror group is 190 mm, the interval between the front surface of the spectrum beam splitter 3 and the visible light collimating mirror group is 240 mm, the interval between the second folding axis reflector 5 and the medium-wave infrared projection mirror group is 50 mm, and the interval between the visible light collimating mirror group and the visible light imaging mirror group is 90 mm.

[0048] For the convenience of description, the parameters of each optical device in this embodiment are described in a table:

[0049]

[0050]

[0051]

[0052]

[0053] For the optical devices in Tables 1 to 5 above, whose surface types are paraboloid, hyperboloid and aspheric, the following equation can be used to calculate the sag:

[0054] In the formula, Indicates the height of the arrow. represents the curvature, r represents the radius of the ring, represents the coefficient of the quadratic term, represents the fourth-order aspheric coefficient, represents the sixth-order aspheric coefficient, represents the 8th-order aspheric coefficient, Indicates the 10th-order aspheric coefficient.

[0055] Based on the above parameters, the aperture of the moving target measurement optical system is Φ450mm. The focal length of the visible light imaging system where the camera target is located is 4500mm, and the F number is 10, which is suitable for cameras with a resolution of 1920×1080 and a pixel size of 10μm×10μm. The focal length of the medium-wave infrared measurement system where the thermal imager target is located is 900mm, and the F number is 2, which is suitable for cooled infrared thermal imagers with a resolution of 640×512 and a pixel size of 15μm×15μm. The receiving focal length of the laser rangefinder where the detector target is located is 550mm, and the field of view is 0.64mrad×0.64mrad.

[0056] The working principle of the above embodiment is: A concave parabola primary mirror 1 converges the light incident parallel to the optical axis at its focus, and the primary mirror 1 is the entrance pupil of the system. For the visible light and laser ranging receiving optical path, the secondary mirror 2 is a reflector, and one focus of the secondary mirror 2 coincides with the focus of the primary mirror 1, and the light is converged at the other focus of the hyperboloid, that is, the primary image plane. A spectral beam splitter 3 is set in front of the primary image plane to reflect the visible light path and transmit the laser light path. The laser light path transmitted by the secondary mirror 2 is compensated by a plane correction plate 6 for the astigmatism introduced by the spectral beam splitter 3 in the convergent light path, and then the positive focal bending lens 7 and the first positive focal biconvex lens 8 converge the light onto the detector target surface. The visible light path reflected by the spectral beam splitter 3 converges to the primary image plane and continues to propagate, the light beam diverges, and is collimated into a parallel light beam by the visible light collimator group, and the aperture stop is conjugated to the parallel light path by the primary mirror 1. The parallel light is folded to the second layer above the main optical system with the optical axis parallel to the optical axis of the primary and secondary mirrors 2 by the third folding reflector 14. The folded parallel light beams are converged to the camera target surface by the visible light imaging lens group. For the medium-wave infrared optical path, the secondary mirror 2 is a lens, which diverges the converged light of the primary mirror 1 and increases the focal length of the primary mirror 1 and the secondary mirror 2, so as to fold the medium-wave infrared optical path above the main optical system, and then fold the infrared optical path to the second layer above the main optical system by the first folding reflector 4 and the second folding reflector 5. After folding, the optical axis is parallel to the optical axis of the primary mirror 1 and the secondary mirror 2. In the medium-wave infrared projection lens group, a 4-piece structure is adopted to converge the divergent light after the infrared primary image of the primary mirror 1 and the secondary mirror 2 again, and the image is formed on the target surface of the thermal imager, and the entrance pupil is projected to the cold screen position to achieve the matching of the aperture and the cold screen.

[0057] Based on the above-mentioned moving target measurement optical system, the present application also proposes a moving target measurement method, which may include: The laser beam and the visible light are respectively irradiated onto the moving target, and the reflected laser beam and the visible light are incident on the primary mirror 1 of the Cassegrain mirror group; And the medium-wave infrared radiation emitted by the moving target is incident on the main mirror 1 of the Cassegrain mirror group.

[0058] When performing specific measurements and calculations, you can: Calculate the distance from the moving target to the measuring optical system based on the laser signal in the laser light path converged by the detector target surface; Obtain a visible light image based on the visible light path converged by the camera target surface, identify and track the moving target, determine the angle between the moving target and the visual axis of the measuring optical system, and determine the position of the target in two-dimensional space in combination with the distance from the moving target to the measuring optical system; The medium-wave infrared image is obtained according to the medium-wave infrared light path converged by the target surface of the thermal imager to capture and track the target and determine the temperature distribution of the moving target.

[0059] Further verify the technical effect of this application. Figure 2 As shown in the figure, it is the MTF curve of the visible light imaging optical system with a spatial frequency of 50lp / mm. Figure 3 As shown in the figure, it is the point diagram of the visible light imaging optical system. Figure 4 As shown in the figure, it is the MTF curve of the medium-wave infrared measurement optical system with a spatial frequency of 33lp / mm. Figure 5 The figure shows the spot diagram of the medium-wave infrared measurement optical system. Figures 2 to 5 It can be seen that the MTF of the visible light imaging optical system is better than 0.35 when the spatial frequency is 50lp / mm, and the diameter of the spot diagram is less than 0.01mm, which is smaller than one pixel; the MTF (Modulation Transfer Function) of the medium-wave infrared measurement optical system is better than 0.31 when the spatial frequency is 33lp / mm, and the diameter of the spot diagram is less than 0.008mm, which is smaller than one pixel. Both the visible light imaging and medium-wave infrared measurement optical systems have good imaging quality and meet the requirements for target observation. Figure 6 The following is the energy curve of the enclosing circle of the laser ranging receiving optical system. Figure 6 It can be seen that 80% of the energy of the enclosed circle of the laser ranging receiving optical system is concentrated within a radius of 6μm, which has a good degree of energy concentration and meets the requirements for receiving target ranging echoes.

[0060] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A moving target measurement optical system, characterized in that: It includes a main optical system, a laser ranging receiving and correction lens group, a visible light collimating lens group, a visible light imaging lens group and a medium-wave infrared projection lens group; The primary optical system comprises a Cassegrain mirror group and a spectral beam splitter (3); light incident parallel to the optical axis is incident from the primary mirror (1) of the Cassegrain mirror group; the spectral beam splitter (3) is located in front of the primary image surface of the secondary mirror (2) of the Cassegrain mirror group, so as to reflect the visible light path and transmit the laser light path; After the laser light path is incident on the laser ranging receiving and correction lens group, it converges to the detector target surface and is used to calculate the distance from the moving target to the measuring optical system; After the visible light path is incident on the visible light collimating lens group, the visible light path is turned to be parallel to the optical axis, and the visible light path is located in the second layer above the optical axis; The visible light path on the second layer is incident on the visible light imaging lens group and then converges to the camera target surface, which is used to identify and track the moving target, determine the angle between the moving target and the visual axis of the measuring optical system, and determine the position of the target in two-dimensional space in combination with the distance from the moving target to the measuring optical system; The medium-wave infrared light path transmitted through the secondary mirror (2) of the Cassegrain mirror assembly is parallel to the optical axis after being turned and is located in the second layer above the optical axis; The medium-wave infrared light path located on the second layer is incident on the medium-wave infrared projection lens group and then imaged on the target surface of the thermal imager, which is used to capture and track the target and determine the temperature distribution of the moving target.

2. The moving target measurement optical system according to claim 1, characterized in that: The main optical system further comprises a first folding axis reflector (4) and a second folding axis reflector (5); The medium-wave infrared light path transmitted through the secondary mirror (2) of the Cassegrain mirror group is turned in turn through the first folding axis reflector (4) and the second folding axis reflector (5) and then becomes parallel to the optical axis.

3. The moving target measurement optical system according to claim 2, characterized in that: The laser distance measurement receiving correction lens group comprises a plane correction plate (6), a positive focal length bending image plane lens (7) and a first positive focal length biconvex lens (8) which are sequentially arranged along the laser light path; the laser light path passes through the plane correction plate (6) to compensate for the astigmatism introduced by the spectral beam splitter (3), and is converged sequentially through the positive focal length bending image plane lens (7) and the positive focal length biconvex lens.

4. The moving target measurement optical system according to claim 3, characterized in that: The visible light collimating lens group comprises a second positive power biconvex lens (9), a first meniscus lens (10), a first negative power biconcave lens (11), a negative power cemented lens (12), a second meniscus lens (13) and a third folding axis reflector (14) which are sequentially arranged along the visible light path; The first meniscus lens (10) is a meniscus lens with positive optical power that bends toward a parallel optical path, and the second meniscus lens (13) is a meniscus lens that bends toward a primary image plane.

5. The moving target measurement optical system according to claim 4, characterized in that: The visible light imaging lens group comprises a third meniscus lens (15), a fourth meniscus lens (16), a third positive focal power biconvex lens (17), a second negative focal power biconcave lens (18), a fifth meniscus lens (19) and a sixth meniscus lens (20) which are sequentially arranged along the visible light path located on the second layer; The third meniscus lens (15) is a positive focal meniscus lens bent toward the image side, the fourth meniscus lens (16) is a negative focal meniscus lens bent toward the image side, the fifth meniscus lens (19) is a positive focal meniscus lens bent toward the image side, and the sixth meniscus lens (20) is a positive focal meniscus lens bent toward the image side.

6. The moving target measurement optical system according to claim 5, characterized in that: The medium-wave infrared projection lens group comprises a first silicon lens (21), a negative optical power biconcave germanium lens (22), a positive optical power zinc sulfide lens (23) bent toward the image plane, and a second silicon lens (24) with positive optical power bent toward the image plane, which are sequentially arranged along a medium-wave infrared optical path located on a second layer.

7. The moving target measurement optical system according to claim 6, characterized in that: The primary mirror (1) of the Cassegrain mirror assembly is a concave parabolic mirror, the secondary mirror (2) of the Cassegrain mirror assembly is a convex hyperbolic spectral splitter secondary mirror (2), and the surface type of at least one of the first positive focal power biconvex lens (8), the fourth meniscus lens (16) and the second negative focal power biconcave lens (18) is aspherical; The calculation method of the vector height of paraboloids, hyperboloids and aspherical surfaces includes: in, Indicates the height of the arrow. represents the curvature, r represents the radius of the ring, represents the coefficient of the quadratic term, represents the 4th-order aspheric coefficient, represents the sixth-order aspheric coefficient, represents the 8th-order aspheric coefficient, Indicates the 10th-order aspheric coefficient.

8. The moving target measurement optical system according to claim 7, characterized in that: The focal length of the visible light imaging system where the camera target surface is located is 4500 mm, and the F number is 10; The focal length of the medium-wave infrared measurement system where the thermal imager target surface is located is 900 mm, and the F number is 2; The receiving focal length of the laser rangefinder where the detector target surface is located is 550mm.

9. A moving target measurement method, based on the moving target measurement optical system according to any one of claims 1 to 8, characterized in that: include: The laser beam and the visible light are respectively irradiated onto the moving target, and the reflected laser beam and the visible light are incident on the primary mirror (1) of the Cassegrain mirror group; The medium-wave infrared radiation emitted by the moving target is incident on the primary mirror (1) of the Cassegrain mirror group.

10. The moving target measurement method according to claim 9, characterized in that: Also includes: Calculate the distance from the moving target to the measuring optical system based on the laser signal in the laser light path converged by the detector target surface; Obtain a visible light image based on the visible light path converged by the camera target surface, identify and track the moving target, determine the angle between the moving target and the visual axis of the measuring optical system, and determine the position of the target in two-dimensional space in combination with the distance from the moving target to the measuring optical system; The medium-wave infrared image is obtained according to the medium-wave infrared light path converged by the target surface of the thermal imager to capture and track the target and determine the temperature distribution of the moving target.

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