Multi-aperture imaging-based space remote sensing target positioning optical system and calibration method

Abstract

The application relates to a multi-aperture imaging space remote sensing target positioning optical system and a calibration method, and relates to the field of remote sensing and aerospace imaging optical instruments. The application solves the contradiction between the requirements of a large field of view and high resolution imaging of a traditional single-aperture optical imaging system, and realizes accurate positioning of a target to meet the intelligent requirements of a multi-aperture optical imaging system. The multi-aperture imaging space remote sensing target positioning sub-aperture imaging optical system comprises an electromagnetic vibration mirror, a beam-reducing telescope group, a fast reflection mirror and a rear focusing mirror group. The beam-reducing telescope group and the rear focusing mirror group are connected through the fast reflection mirror, and the light beam is connected with an imaging branch through the electromagnetic vibration mirror. After the imaging light beam passes through the telescope system, the imaging light beam is reflected by the fast reflection mirror and focused on a detector to form an image. The application is also suitable for a mobile platform for fast positioning and high-precision capturing of a dynamic target in the field of industrial precision machining and space remote sensing.

Description

Optical System and Calibration Method for Space Remote Sensing Target Positioning Based on Multi-Aperture Imaging Technical Field

[0001] This invention relates to the field of remote sensing and space imaging optical instruments, specifically to a space remote sensing target positioning optical system and calibration method based on multi-aperture imaging. Background Technology

[0002] With the rapid development of the optoelectronic field, optoelectronic imaging systems with both large field of view and high spatial resolution have a wide range of application needs. Meanwhile, the shift in international space security strategies and the continuous development of satellite close-in technology have made accurately identifying various abnormal behaviors of high-value space targets to achieve target threat assessment and intent judgment a research hotspot. Traditional single-aperture imaging systems face a trade-off between large field of view and high resolution performance, making it impossible to simultaneously achieve both. To balance the hardware cost of the optical system and imaging quality, the method of using small-aperture detection combined with imaging to achieve equivalent large-aperture imaging quality has become a new research hotspot.

[0003] Multi-aperture camera stitching is one of the main research directions in large field-of-view billion-pixel imaging in recent years. This imaging method is independently detected by a single-channel camera, which is not limited by the number of detector pixels. The imaging cycle is greatly shortened. The final image is also stitched together from images acquired by multi-channel imaging cameras. Furthermore, the positions of the multi-channel imaging cameras are relatively fixed, which is very advantageous for mechanical installation, image calibration, and image reconstruction.

[0004] Traditional large-aperture single-aperture systems, such as astronomical telescopes and satellite remote sensing cameras, face the problem that "the larger the aperture, the more exponentially the size, weight, and cost increase." For example, an optical lens with a diameter of 3 meters can weigh more than 10 tons, with a manufacturing cost exceeding $100 million, and it cannot be adapted to lightweight platforms such as small satellites and drones. However, the weight of a single small-aperture unit can be only 1 / 100th of that of a large-aperture unit with the same performance, and the array arrangement can make full use of space, such as by attaching it to the side wall of a satellite or the wing of a drone, without reserving a huge space for a single ultra-large lens.

[0005] Imaging systems are prone to unit failures in harsh environments such as space radiation. Traditional single-aperture systems, lacking backups, will directly lead to mission failure if the lens or detector is damaged. However, the redundancy design of multi-aperture imaging gives it strong resilience against failures. For example, existing "keyhole" reconnaissance satellites use multi-aperture imaging systems. Even if 20% of the lens units are damaged by space debris, the remaining units can be adjusted to maintain 80% of the imaging performance, ensuring that the reconnaissance mission is not interrupted. Summary of the Invention

[0006] This invention overcomes the contradiction between the large field of view and high-resolution imaging requirements of traditional single-aperture optical imaging systems, and achieves the intelligent requirements of multi-aperture optical imaging systems by enabling precise target positioning.

[0007] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0008] This invention proposes a space remote sensing target positioning optical system based on multi-aperture imaging. The optical system adopts a multi-aperture imaging design and stitches together the sub-apertures to obtain a multi-aperture imaging system. Specifically, it includes: a beam-shrinking telescope group and a fast-reflecting mirror. The beam-shrinking telescope group includes a single-aperture optical system composed of a front telescope group, an electromagnetic galvanometer, and a rear focusing mirror group.

[0009] The imaging beam for locating the target passes through an electromagnetic galvanometer, a front telescope group, a fast-reflecting mirror, and a rear focusing mirror group, and is finally focused onto the detector for imaging. The front telescope group is used to reduce the beam size, so that the beam energy is concentrated on the detector, the target point, or a designated location, achieving clear imaging, precise energy focusing, or beam pointing. The fast-reflecting mirror adjusts the angle of the reflecting mirror surface in real time through high-precision drive and feedback control, thereby rapidly changing the beam propagation direction to meet the needs of dynamic target tracking, beam stabilization, or optical path correction. The rear focusing mirror group is used to control the convergence degree of the beam, so that the beam energy is concentrated on the detector.

[0010] Furthermore, a preferred embodiment is provided, wherein the front telescope group is axially arranged from right to left with a first single lens, a second single lens, a third single lens, a fourth single lens, a first cemented lens, and a first filter;

[0011] The first single lens has positive optical power and is implemented using a biconvex spherical structure;

[0012] The second single lens has positive optical power, with its concave surface facing the incident direction of the light beam and its convex surface facing the exit direction of the light beam, in order to adapt to the curvature of the exit light field of the biconvex positive lens;

[0013] The third single lens has negative optical power. The convex surface of the third single lens faces the direction of beam incident and the concave surface faces the direction of beam exit. The negative optical power of the third single lens, together with the first and second single lenses, forms a positive-positive-negative optical power combination.

[0014] The fourth single lens has positive optical power and consists of at least two optical glass lenses with different refractive indices bonded together with an optical adhesive.

[0015] The first cemented lens has negative optical power. The optical power parameters of the first cemented lens are asymmetrically matched with those of the third single lens. By finely adjusting the wavefront curvature of the beam, the divergence angle of the output beam is controlled within 0.1 mrad, and the parallelism error does not exceed 5 μrad.

[0016] The first filter uses an optical flat substrate and has a specific wavelength anti-reflection and filtering composite film layer deposited on its surface. The transmission wavelength range of the composite film layer matches the working wavelength of the space remote sensing target imaging and is used to filter out stray light outside the working wavelength. The second single lens, the third single lens, and the first cemented lens are all meniscus structures.

[0017] Furthermore, a preferred embodiment is provided in which the electromagnetic galvanometer controls the oscillation of the mirror surface around the X-axis or Y-axis via electromagnetic drive, which is used to correct the beam propagation direction of the sub-aperture in real time, dynamically fine-tune the beam pointing of the sub-aperture, and ensure that the optical axis of each sub-aperture is consistent with the reference; the electromagnetic galvanometer and the fast reflector are both mounted on their respective bases, and the tilt angle of their reflecting or transmitting surfaces is 45° with the horizontal plane.

[0018] Furthermore, a preferred embodiment is provided, wherein the optical path in the front telescope group is as follows:

[0019] The imaging beam reflected from the target under test is first incident on the electromagnetic galvanometer of the system. After being calibrated by the electromagnetic galvanometer, the beam enters the asymmetrically designed front telescope group. The first and second single lenses with positive optical power work together to initially converge the incident beam, using the refractive properties of the positive lenses to bring the diverging beam closer to the optical axis. The third single lens with negative optical power is then introduced, and the multi-lens cemented structure of the fourth single lens improves the uniformity of the beam energy. The first cemented lens further fine-tunes the divergence angle of the beam to ensure that the output beam is a small-aperture parallel beam, matching the light transmission requirements of the subsequent fast-reflecting mirror and the rear focusing lens group. Finally, a flat plate filter removes stray light from the beam.

[0020] Furthermore, a preferred embodiment is provided, wherein the specific optical path in the rear focusing lens group is as follows:

[0021] The rear focusing lens group includes a fifth single lens, a sixth single lens, a seventh single lens, and an eighth single lens, which are arranged radially from bottom to top.

[0022] After being stabilized by the fast-reflecting mirror, the beam finally enters the rear focusing lens group; the fifth single lens uses positive optical power to initially converge the beam, turning parallel light into convergent light; the sixth single lens corrects the aberrations generated during the convergence process and optimizes the beam wavefront curvature; the seventh single lens is used to reduce the beam spot size; the eighth single lens is used to precisely control the focal position, focusing the beam energy onto the photosensitive surface of the detector in the optical system. At this time, the detector receives the focused imaging beam, converts it into an electrical signal and transmits it to the data processing module. Combined with the multi-aperture stitching method, a high-resolution, large-field-of-view image of the target is formed, completing the positioning and imaging of the space remote sensing target.

[0023] Furthermore, a preferred embodiment is provided, wherein the fifth single lens adopts a double-spherical convex structure, and the radius of curvature of the double-spherical convex surface is designed according to the aperture of the output beam of the front telescope group and the preset focusing magnification, which is used to convert the incident small-aperture parallel beam into a low-convexity converging beam; the sixth single lens adopts a double-spherical concave structure, and the radius of curvature of the concave surface is asymmetrically matched with the radius of curvature of the fifth single lens, which is used to correct aberrations; the radius of curvature of the convex surface of the seventh single lens is smaller than that of the fifth single lens, and the optical power is higher than that of the fifth single lens, which is used to enhance the beam convergence; the eighth single lens has its concave surface facing the beam incident direction and its convex surface facing the beam exit direction, and the curvature of the eighth single lens is adapted to the wavefront curvature of the output beam of the seventh single lens, which is used to control the focal position and the shape of the beam spot.

[0024] Furthermore, a preferred embodiment is provided in which all lenses are made of materials not limited to optical glass.

[0025] Furthermore, in a preferred embodiment, the pixel size of the detector is equal to 9.76. .

[0026] A calibration method for a space remote sensing target positioning optical system based on multi-aperture imaging includes the following steps:

[0027] Step 1: Start the main control terminal of the optical system and trigger the power management unit through the embedded control module to supply power to the electromagnetic galvanometer, front telescope group, fast reflector, rear focusing lens group and detector;

[0028] Step 2: A test beam is emitted by simulating a target light source and guided to the electromagnetic galvanometer. The mirror angle of the electromagnetic galvanometer is finely adjusted to ensure that the beam propagates along the system's reference optical axis and enters the front telescope group. The initial focusing effect of the first single lens on the test beam is monitored to ensure that the beam converges towards the optical axis. The second single lens is used to correct the initial spherical aberration introduced by the first single lens, so that the phase difference between the beam edge and the center is controlled within the allowable range. The axial chromatic aberration generated by the first and second single lenses is compensated by negative optical power. At the same time, the beam divergence angle is monitored to calibrate the output beam into strictly parallel light, retaining only the beam that matches the working wavelength, so that the beam purity is ≥90%.

[0029] Step 3: Generate a dynamic target trajectory through the main control terminal, trigger the fast-reflection mirror response mechanism, and monitor its angle adjustment speed when the target moves towards the edge of the field of view. This is to ensure that the beam can be pulled back to the effective receiving range of the rear focusing lens group within milliseconds. Simulate small vibrations of the carrier and record the real-time feedback adjustment data of the fast-reflection mirror to verify whether it can accurately compensate for the optical path offset caused by vibration, ensuring that the beam propagation path is stable and that there is no situation of deviating from the subsequent optical link. When the fast-reflection mirror adjusts its angle, the dynamic response of the electromagnetic galvanometer is monitored simultaneously to ensure that the two work together to correct the beam direction of the sub-aperture and unify the optical axis reference of each sub-aperture.

[0030] Step 4: Introduce the parallel beam stabilized by the fast-reflection mirror into the rear focusing lens group;

[0031] Step 5: Start the multi-aperture system and make synchronous fine adjustments to the electromagnetic mirrors of each sub-aperture to ensure that the optical axes of all sub-apertures are aligned with the system's reference optical axis. The data processing module calls the stitching algorithm to integrate the imaging data of each sub-aperture to form a high-resolution, wide-field-of-view image of the target. At the same time, the target coordinates are calculated to complete the spatial remote sensing target positioning.

[0032] Step 6: The embedded processing module continuously monitors optical path parameters, component status, and imaging data;

[0033] Step 7: After the task is completed or a termination command is received, the electromagnetic galvanometer and fast-reflecting mirror are zeroed, the front telescope group and the rear focusing lens group are reset to their initial optical power parameters, and the focus of the rear focusing lens group is removed from the detector's photosensitive surface; detector preheating is turned off, temperature control of each module is stopped, and only the main control terminal and storage module are powered; the parameters in Step 6 are stored in the solid-state storage module in a dual-redundancy manner; the main control terminal automatically generates a task report, which includes imaging resolution, positioning accuracy, beam parameters, and component operating status statistics, and is exported as a PDF or uploaded to the task management platform via an encrypted interface.

[0034] Furthermore, a preferred embodiment is provided, wherein the method for introducing the parallel beam stabilized by the fast-reflection mirror into the rear focusing lens group for calibration in step four includes the following steps:

[0035] S4.1, Preliminary Convergence of the Fifth Single Lens: Using positive optical power, the parallel beam is converted into a low-convergence convergent beam. Based on the output beam aperture of the front telescope group, the curvature radius of the convex surface of the fifth single lens is adjusted to ensure that the beam has no obvious edge scattering.

[0036] S4.2 Sixth Single Lens Aberration Correction: The spherical aberration and axial chromatic aberration introduced by the fifth single lens are offset by negative optical power, and the wavefront curvature of the beam is detected to ensure that there is no obvious distortion;

[0037] S4.3, Seventh Single Lens Enhanced Convergence: Utilizing a higher optical power than the fifth single lens, the beam spot size is compressed to within 1.2 times the detector pixel size;

[0038] S4.4, Precise Focusing of the Eighth Single Lens: Adjust the curvature of the meniscus structure of the eighth single lens to match the wavefront curvature of the output beam of the seventh single lens, ensuring that the beam focus falls strictly on the center area of ​​the detector's photosensitive surface. At the same time, detect the energy concentration of the light spot, correct residual field distortion, and ensure consistent imaging resolution across the entire field of view of the detector.

[0039] Input the focused test beam into the detector, monitor its efficiency in converting optical signals into electrical signals, verify the stability of the electrical signal transmission to the data processing module, and ensure that there is no signal loss or distortion.

[0040] The advantages of this invention are:

[0041] The spatial remote sensing target positioning optical system and calibration method based on multi-aperture imaging described in this invention utilizes a five-channel system that can simultaneously capture target position information from different parallel viewpoints. An algorithm performs consistency verification on the five channels of data, eliminating abnormal data that may arise from optical distortion or environmental interference in a single channel system, retaining only highly overlapping and valid information, significantly reducing random errors and achieving sub-pixel-level precise positioning. This invention achieves synergy between "wide field-of-view search and local high-precision positioning" through reasonable field-of-view allocation. It first rapidly scans a large area using multiple channels to lock onto the target, then focuses on any of the high-precision channels to complete the positioning, avoiding the contradiction between single-aperture field of view and accuracy.

[0042] The multi-aperture optical system with sub-pixel precision constructed in this invention enables high-precision positioning and high-resolution imaging of space remote sensing targets. At the same time, it verifies the multi-aperture sub-pixel architecture of "five single apertures in synergistic configuration", providing an innovative technical solution for the field of space remote sensing. It also meets the requirements of low cost, easy assembly and adjustment, compact structure, good optical axis consistency and high-precision control capability of optoelectronic system architecture.

[0043] This invention is also applicable to scenarios that require rapid capture and precise positioning of moving targets. Attached Figure Description

[0044] Figure 1 is a schematic diagram of the structure of the space remote sensing target positioning optical system based on multi-aperture imaging as described in Embodiment 1.

[0045] Figure 2 is a schematic diagram of the front telescope group in the space remote sensing target positioning optical system based on multi-aperture imaging as described in Embodiment 1.

[0046] Figure 3 shows the MTF curves of the multi-aperture optical system described in Embodiment 1 at a Nyquist frequency of 52 lp / mm for each field of view.

[0047] Figure 4 is a distortion diagram of the space remote sensing target positioning optical system based on multi-aperture imaging as described in Embodiment 1.

[0048] Among them, (a) and (b) represent distortion in the Y direction, and (c) and (d) represent distortion in the X direction.

[0049] Figure 5 is an RMS dot plot of the space remote sensing target positioning optical system based on multi-aperture imaging as described in Embodiment 1.

[0050] Figure 6 is an MTF curve of the 20° multi-aperture optical system described in Embodiment 1.

[0051] Figure 7 is the MTF curve of the -40° multi-aperture optical system described in Embodiment 1.

[0052] Figure 8 is an MTF curve of the 60° multi-aperture optical system described in Embodiment 1.

[0053] Figure 9 is a dot diagram of the 20° multi-aperture optical system described in Embodiment 1.

[0054] Figure 10 is a dot diagram of the -40° multi-aperture optical system described in Embodiment 1.

[0055] Figure 11 is a dot diagram of the 60° multi-aperture optical system described in Embodiment 1.

[0056] Figure 12 is a flowchart of the operation of the space remote sensing target positioning optical system based on multi-aperture imaging according to Embodiment 2.

[0057] Figure 13 is a schematic diagram of the optical system for positioning space remote sensing targets based on multi-aperture imaging as described in Embodiment 1.

[0058] Among them, electromagnetic galvanometer 1, first single lens 2, second single lens 3, third single lens 4, fourth single lens 5, first cemented lens 6, first filter 7, fast reflector 8, fifth single lens 9, sixth single lens 10, seventh single lens 11, and eighth single lens 12. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0060] Implementation Method 1: Referring to Figures 1 to 11 and Figure 13, this implementation method proposes a space remote sensing target positioning optical system based on multi-aperture imaging. The optical system includes an electromagnetic galvanometer 1, a first single lens 2, a second single lens 3, a third single lens 4, a fourth single lens 5, a first cemented lens 6, a first filter 7, a fast-reflecting mirror 8, a fifth single lens 9, a sixth single lens 10, a seventh single lens 11, and an eighth single lens 12 arranged sequentially along the optical axis from the object side to the image side.

[0061] In this embodiment, the space remote sensing target positioning sub-aperture optical system adopts an asymmetric design. The imaging beam reflected from the target first enters the electromagnetic galvanometer 1, and after being calibrated by it, it enters the front telescope group. The beam is initially converged by the first single lens 2 and the second single lens 3, then aberration is corrected by the third single lens 4, energy uniformity is improved by the fourth single lens 5, the first cemented lens 6 is calibrated to be small-aperture parallel light, and stray light is filtered out by the first filter 7. The beam-converged beam enters the fast-reflecting mirror 8, whose angle is adjusted in real time to stabilize the optical path. Subsequently, the beam enters the rear focusing lens group, is initially converged by the fifth single lens 9, aberration is corrected by the sixth single lens 10, convergence is enhanced by the seventh single lens 11, and precise focusing is achieved by the eighth single lens 12. Finally, it is imaged on a detector with a pixel size of 9.76 μm, and the target positioning is completed by combining it with a stitching algorithm.

[0062] The electromagnetic galvanometer 1 controls the minute oscillation of its surface around the X-axis or Y-axis via electromagnetic drive, real-time correcting the beam propagation direction of the sub-apertures, dynamically fine-tuning the beam pointing of the sub-apertures, calibrating optical axis offsets caused by processing errors and environmental disturbances, and ensuring a unified reference for the optical axes of each sub-aperture. It can quickly respond to and track dynamic targets, coordinate multi-aperture relay tracking, and prevent target misses. It can also compensate for tilt aberrations caused by carrier vibrations, optimize imaging clarity, and adjust the beam propagation path to ensure synchronized signal timing for each sub-aperture, helping the system achieve large field of view, high resolution, and high stability imaging. Both the electromagnetic galvanometer 1 and the fast-reflecting mirror 8 are mounted on their respective bases, and the tilt angle of their reflecting or transmitting surfaces is 45° to the horizontal plane.

[0063] In this embodiment, the target imaging beam from the front telescope group is reflected by the electromagnetic mirror 1 and reaches the first single lens 2, which initially converges the parallel target beam, focusing the beam towards the system's optical axis. The second single lens 3, with positive optical power, enhances the beam convergence and corrects spherical aberration, reducing the propagation phase difference between the beam edge and center. The third single lens 4, with negative optical power, specifically compensates for chromatic aberration generated by the preceding lens combination, while suppressing abnormal increases in the beam divergence angle. The fourth single lens 5, with positive optical power, further eliminates residual chromatic aberration and higher-order spherical aberration, while utilizing the synergistic refraction of multiple lenses to make the energy distribution of the beam cross-section more uniform. The first cemented lens 6, with negative optical power, meets the reflection efficiency requirements of the subsequent fast-reflecting mirror for incident parallel light. The first filter 7 selectively filters out stray light outside the working wavelength, reducing interference from stray light on the signal-to-noise ratio of the subsequent detector imaging.

[0064] In this embodiment, the beam stabilized by the fast-reflecting mirror ultimately enters the rear focusing lens group, which consists of a fifth single lens 9, a sixth single lens 10, a seventh single lens 11, and an eighth single lens 12, arranged radially from bottom to top. The fifth single lens 9 initially converges the beam using positive optical power, converting parallel light into convergent light. Subsequently, the sixth single lens 10 corrects aberrations (such as field curvature and distortion) generated during the convergence process, optimizing the beam wavefront curvature. Next, the seventh single lens 11 further enhances the convergence effect, reducing the beam spot size. Finally, the eighth single lens 12 precisely controls the focal point position, accurately focusing the beam energy onto the photosensitive surface of the system's detector (such as a CCD or CMOS). At this point, the detector receives the focused imaging beam, converts it into an electrical signal, and transmits it to the data processing module. Combined with a multi-aperture stitching algorithm, a high-resolution, large-field-of-view image of the target is finally formed, completing the localization and imaging of the space remote sensing target.

[0065] In this embodiment, the first single lens 2 in the front telescope group is made of H-FK61B material with a refractive index of 1.497 and an Abbe number of 81.5; the second lens 3 is made of H-ZK20 material with a refractive index of 1.607 and an Abbe number of 59.5; the third single lens 4 is made of H-ZF50 material with a refractive index of 1.740 and an Abbe number of 27.76; the fourth single lens 5 is made of H-ZF88 material near the object side with a refractive index of 1.945 and an Abbe number of 17.94, and is made of H-TF3L material near the image side with a refractive index of 1.613 and an Abbe number of 29.5; the first cemented lens 6 is made of H-ZLAF76 material with a refractive index of 1.816 and an Abbe number of 46.6; and the filter material is C79-80 material with a refractive index of 1.516 and an Abbe number of 64.2.

[0066] In this embodiment, the fifth single lens 9 in the rear focusing lens group is made of H-ZK50GT material with a refractive index of 1.607 and an Abbe number of 56.0; the sixth single lens 10 is made of H-ZLAF71 material with a refractive index of 1.806 and an Abbe number of 40.9; the seventh single lens 11 is made of H-ZK6 material with a refractive index of 1.568 and an Abbe number of 63.0; and the eighth single lens 12 is made of H-LAF3B material with a refractive index of 1.755 and an Abbe number of 47.8.

[0067] In this embodiment, all lenses use optical glass as the material, which is common, readily available, and easy to process. The optical system for positioning spatial remote sensing targets based on multi-aperture imaging can be replaced with optical resin or optical crystal material according to specific needs.

[0068] Figure 2 shows a schematic diagram of the front telescope assembly structure of the present invention. The imaging beam reflected from the target (such as a satellite or ground observation point) first enters the electromagnetic galvanometer 1 of the system. After being calibrated by the electromagnetic galvanometer, the beam enters the asymmetrically designed front telescope group, which consists of a first single lens 2, a second single lens 3, a third single lens 4, a fourth single lens 5, a first cemented lens 6, and a first filter 7, arranged sequentially from right to left along the optical axis. The first single lens 2, with positive optical power, works in conjunction with the second single lens 3 to initially converge the incident beam, using the refractive properties of the positive lenses to bring the diverging beam closer to the optical axis. Subsequently, the third single lens 4, with negative optical power, intervenes to correct aberrations such as spherical aberration and chromatic aberration introduced by the first two lenses, avoiding beam wavefront distortion. Next, the fourth single lens 5 further enhances the beam-converging effect, improving the uniformity of beam energy through the multi-lens cemented structure. Afterward, the first cemented lens 6 fine-tunes the beam divergence angle to ensure that the output beam is a small-aperture parallel beam, matching the light transmission requirements of the subsequent fast-reflecting mirror and rear mirror group. Finally, the first filter 7 filters out stray light from the beam, improving beam purity. The entire process achieves the transformation from "large-aperture incident beam to small-aperture parallel beam" while concentrating the beam energy.

[0069] Figure 3 shows the MTF curves of a space remote sensing target positioning optical system based on multi-aperture imaging at a Nyquist frequency of 52 lp / mm for each field of view. Figures 6 to 8 show the MTF curves of the space remote sensing target positioning multi-aperture optical system at various temperatures. MTF (Modulation Transfer Function) reflects the imaging quality of the optical system. Specifically, the larger the area enclosed by the x-axis below the MTF curve, the smoother the transition of the MTF curve, and thus the better the imaging quality of the optical system. As can be seen from the figures, the MTF of this space remote sensing target positioning multi-aperture optical system coincides with the diffraction limit at its limiting frequency, indicating that the system has excellent imaging performance.

[0070] Figure 4 shows the field curvature and distortion diagrams of the space remote sensing target positioning optical system based on multi-aperture imaging. We can see that the system's distortion in the Y direction is 0.0424%; the distortion in the X direction is 0.0630%; and the maximum distortion is -0.0925%. Furthermore, when the system's distortion is less than 4%, the image deformation is imperceptible. As can be seen from the figure, the system's distortion is less than 0.5%, and there is no easily noticeable distortion in the image.

[0071] Figure 5 shows the RMS dot plot of the multi-aperture optical system. The dot plot reflects the geometric structure of the optical system's imaging. In image quality evaluation, the density of the dot plot can intuitively reflect the quality of the image. The smaller the RMS radius in the dot plot, the smaller the aberrations, and the better the image quality of the system. It can be seen that the light spots in each field of view on the image side are close to or smaller than the Airy disk diameter, and the blur spot radius in each field of view is less than 5 μm, indicating good image quality that meets the image quality requirements.

[0072] Figures 9 to 11 show the RMS dot plots of the multi-aperture optical system at various temperatures. The dot plot reflects the geometric structure of the optical system's imaging. In image quality evaluation, the density of the dot plot can intuitively reflect the quality of the image. The smaller the RMS radius in the dot plot, the smaller the aberrations, and the better the system's imaging quality. It can be seen that at 20℃, the light spots in each field of view of the multi-aperture system are close to or smaller than the Airy disk diameter, and the blur radius in each field of view is less than 5μm; at -40℃, the light spots in each field of view of the multi-aperture system are close to or smaller than the Airy disk diameter, and the blur radius in each field of view is less than 6μm; at 60℃, the light spots in each field of view of the multi-aperture system are close to or smaller than the Airy disk diameter, and the blur radius in each field of view is less than 6μm, indicating good imaging quality that meets the image quality requirements.

[0073] Implementation Method 2: As shown in Figure 12, this implementation method proposes a calibration method for a space remote sensing target positioning optical system based on multi-aperture imaging. The method includes the following steps:

[0074] Step 1: Start the optical system main control terminal. The embedded control module triggers the power management unit to supply power to the electromagnetic galvanometer 1, the front telescope group, the rear focusing lens group, and the detector, ensuring that the voltage of each module is stable within the operating threshold range. Then, the system initialization phase begins, loading and configuring all operating parameters. Power isolation points for non-core circuits are shut down to eliminate interference and provide a clean and stable power supply for subsequent imaging modules, ensuring the system safely and reliably transitions from low-power or standby mode to operational status.

[0075] Step Two: After hardware initialization, the system pre-configures and finely calibrates key optical and electrical parameters according to preset imaging requirements. This process includes fine-tuning the amplitude of the electromagnetic drive device to control the optical components; simultaneously, it combines and adjusts the light power of the illumination unit to optimize the illumination conditions of the target. This creates a repeatable, controllable, and consistent external environment for subsequent high-quality image acquisition.

[0076] Step 3: The system generates multiple (e.g., five) high-precision, strictly synchronized trigger signals through the embedded control module, controlling cameras deployed at different angles respectively. These signals ensure that all cameras expose at the same time, thereby capturing multi-view images of the target at the same instant. The main control terminal triggers the fast-reflection mirror 8 response mechanism, monitoring its angle adjustment speed as the target moves towards the edge of the field of view, ensuring that the beam can be "pulled back" to the rear focusing lens group within milliseconds. When the fast-reflection mirror 8 adjusts its angle, the dynamic response of the electromagnetic galvanometer 1 is monitored simultaneously, ensuring that the two work together to correct the beam direction of the sub-apertures, avoiding optical axis reference offset caused by unit component adjustment, and unifying the optical axis reference of each sub-aperture.

[0077] Step 4: By generating dynamic target trajectories (simulating satellite movement and ground observation point displacement), the effective receiving range of the fifth single lens 9, the sixth single lens 10, the seventh single lens 11, and the eighth single lens 12; simulating minute vibrations of the carrier (such as a satellite platform), recording the real-time feedback adjustment data of the fast-reflecting mirror 8, verifying whether it can accurately compensate for the optical path offset caused by vibration, ensuring the stability of the beam propagation path, and preventing the beam from deviating from the subsequent optical link;

[0078] Step 5: Start the multi-aperture system and fine-tune the electromagnetic mirrors 1 of each sub-aperture synchronously to calibrate the optical axis offset caused by processing errors and environmental disturbances, ensuring that the optical axes of all sub-apertures are aligned with the system's reference optical axis and avoiding beam pointing deviations between sub-apertures; the data processing module calls the stitching algorithm to integrate the imaging data of each sub-aperture, eliminate imaging overlap errors between sub-apertures, form a high-resolution, large field-of-view image of the target, and calculate the target coordinates to complete the spatial remote sensing target positioning.

[0079] Step Six: Under the unified scheduling of the central control software, the five-channel image data and the calculated 3D coordinate data obtained in the previous steps are fused. Through image registration and fusion algorithms, a high dynamic range panoramic image or 3D point cloud model containing multi-view information is generated. Simultaneously, the digital zoom function can be invoked to enhance and display details of the regions of interest in the fusion result, providing users with more comprehensive and intuitive visual feedback.

[0080] Step Seven: After completing a single imaging and data processing cycle, the system stores all valid data generated throughout the process, including the original image, preprocessed image, 3D coordinates, fused image, and system logs, in a designated database for archiving. Subsequently, the imaging task is marked as complete, system resources are released, and the system awaits the next imaging command. This ensures the standardization and traceability of data management, forming a complete closed loop for a single task.

[0081] Those skilled in the art will understand that the above description is merely a preferred embodiment of the present invention, and the features described in the various embodiments and / or technical solutions of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. This is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0082] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended technical solutions are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the present invention. Clearly, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Thus, if these modifications and variations of the present invention fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A calibration method implemented by a space remote sensing target positioning optical system based on multi-aperture imaging, characterized in that, The optical system adopts a multi-aperture imaging design and splices the sub-apertures to obtain a multi-aperture imaging system, specifically including: a beam-shrinking telescope group and a fast-reflecting mirror (8). The beam-shrinking telescope group includes a single-aperture optical system composed of a front telescope group, an electromagnetic galvanometer (1), and a rear focusing mirror group. The imaging beam of the positioning target passes through the electromagnetic galvanometer (1), the front telescope group, the fast-reflecting mirror (8), and the rear focusing mirror group, and is finally focused to obtain the detector image. The front telescope group is used to reduce the beam size, so that the beam energy is concentrated on the detector, the target point, or a designated position to achieve clear imaging, precise energy focusing, or beam pointing. The fast-reflecting mirror (8) is used to adjust the angle of the reflector surface in real time through high-precision drive and feedback control, thereby rapidly changing the position of the reflector. The propagation direction of the beam satisfies dynamic target tracking, beam stabilization, or optical path correction; the rear focusing lens group is used to control the convergence degree of the beam so that the beam energy is concentrated on the detector; the calibration method includes the following steps: Step 1: Start the optical system main control terminal, trigger the power management unit through the embedded control module to supply power to the electromagnetic galvanometer (1), the front telescope group, the fast reflector (8), the rear focusing lens group, and the detector; Step 2: Emit a test beam through a simulated target light source, guide the beam to the electromagnetic galvanometer (1), control the electromagnetic galvanometer (1) to fine-tune the mirror angle to ensure that the beam propagates along the system reference optical axis and enters the front telescope group; monitor the initial convergence effect of the first single lens (2) on the test beam to ensure that the beam is aligned with the optical axis. The beam is focused, and the initial spherical aberration introduced by the first single lens (2) is corrected by the second single lens (3), so that the phase difference between the propagation of the beam edge and the center is controlled within the allowable range; the axial chromatic aberration generated by the first single lens (2) and the second single lens (3) is compensated by negative optical power, and the beam divergence angle is monitored at the same time to calibrate the output beam into strictly parallel light, retaining only the beam that matches the working wavelength, so that the beam purity is ≥90%; Step 3: The dynamic target trajectory is generated by the main control terminal, triggering the fast-reflecting mirror (8) response mechanism, and monitoring its angle adjustment speed when the target moves to the edge of the field of view, so as to ensure that the beam can be pulled back to the effective receiving range of the rear focusing lens group within milliseconds; the small vibration of the carrier is simulated, and the real-time feedback adjustment data of the fast-reflecting mirror (8) is recorded. Verify whether it can accurately compensate for the optical path offset caused by vibration, ensure the stability of the beam propagation path, and prevent the beam from deviating from the subsequent optical link; when the fast-reflecting mirror (8) adjusts the angle, monitor the dynamic response of the electromagnetic galvanometer (1) simultaneously to ensure that the two work together to correct the beam direction of the sub-aperture and unify the optical axis reference of each sub-aperture; step four: introduce the parallel beam stabilized by the fast-reflecting mirror (8) into the rear focusing lens group; step five: start the multi-sub-aperture system, and make synchronous fine adjustments through the electromagnetic galvanometer (1) of each sub-aperture to ensure that the optical axis of all sub-apertures is unified to the system reference optical axis; the data processing module calls the stitching algorithm to integrate the imaging data of each sub-aperture to form a high-resolution, large field-of-view image of the target, and calculates the target coordinates to complete the spatial remote sensing target positioning;Step 6: The embedded processing module continuously monitors the optical path parameters, component status, and imaging data; Step 7: After the task is completed or a termination command is received, the electromagnetic galvanometer (1) and the fast-reflecting mirror are zeroed, the front telescope group and the rear focusing lens group are reset to their initial optical power parameters, and the focus of the rear focusing lens group is removed from the detector's photosensitive surface; the detector preheating is turned off, the temperature control of each module is stopped, and only the main control terminal and the storage module are powered; the parameters in Step 6 are stored in the solid-state storage module in a dual-redundancy manner; the main control terminal automatically generates a task report, which includes imaging resolution, positioning accuracy, beam parameters, and component operating status statistics, and is exported as a PDF or uploaded to the task management platform through an encrypted interface.

2. The calibration method implemented by the space remote sensing target positioning optical system based on multi-aperture imaging according to claim 1, characterized in that, The front telescope group is axially arranged from right to left with a first single lens (2), a second single lens (3), a third single lens (4), a fourth lens (5), a ninth single lens (6), and a first filter (7); the first single lens (2) has positive optical power and is implemented using a double convex spherical structure; the second single lens (3) has positive optical power, with its concave surface facing the beam incident direction and its convex surface facing the beam exit direction, to adapt to the curvature of the exit light field of the first single lens (2); the third single lens (4) has negative optical power, with its convex surface facing the beam incident direction and its concave surface facing the beam exit direction, and the negative optical power of the third single lens (4) forms a positive-positive-negative optical power combination with the first single lens (2) and the second single lens (3); the fourth single lens (5) is a double convex spherical structure; the fifth single lens (6) is a double convex spherical structure; the sixth single lens (7) is a double convex spherical structure; the seventh single lens (8) is a double convex spherical structure; the ninth single lens (9) is a double convex spherical structure; the ninth single lens (10) is a double convex spherical structure; the ninth single lens (11) is a double convex spherical structure; the ninth single lens (12 ... The lens (5) has positive optical power. The fourth single lens (5) consists of at least two optical glass lenses with different refractive indices bonded together by an optical adhesive. The ninth single lens (6) has negative optical power. The optical power parameters of the ninth single lens (6) are asymmetrically matched with those of the third single lens (4). By finely adjusting the wavefront curvature of the beam, the divergence angle of the output beam is controlled within 0.1 mrad, and the parallelism error does not exceed 5 μrad. The first filter (7) uses an optical flat substrate and is coated with a specific wavelength anti-reflection and filtering composite film. The transmission wavelength range of the composite film is matched with the working wavelength of the space remote sensing target imaging, and is used to filter out stray light outside the working wavelength. The second single lens (3), the third single lens (4), and the ninth single lens (6) are all meniscus structures.

3. The calibration method implemented by the space remote sensing target positioning optical system based on multi-aperture imaging according to claim 1, characterized in that, The electromagnetic galvanometer (1) controls the oscillation of the mirror surface around the X-axis or Y-axis by electromagnetic drive, which is used to correct the beam propagation direction of the sub-aperture in real time, dynamically fine-tune the beam direction of the sub-aperture, and ensure that the optical axis of each sub-aperture is consistent with the reference. The electromagnetic galvanometer (1) and the fast reflector (8) are both mounted on their respective bases, and the tilt angle of their reflecting or transmitting surfaces is 45° with the horizontal plane.

4. The calibration method implemented by the space remote sensing target positioning optical system based on multi-aperture imaging according to claim 1, characterized in that, The specific optical path in the rear focusing lens group is as follows: The rear focusing lens group includes a fifth single lens (9), a sixth single lens (10), a seventh single lens (11), and an eighth single lens (12). The fifth single lens (9), the sixth single lens (10), the seventh single lens (11), and the eighth single lens (12) are arranged radially from bottom to top. The beam stabilized by the fast-reflecting mirror (8) finally enters the rear focusing lens group. The fifth single lens (9) uses positive optical power to initially converge the beam, so that the parallel light is converted into convergent light. The sixth single lens (10) is used to correct the aberrations generated during the convergence process and optimize the wavefront curvature of the beam. The seventh single lens (11) is used to reduce the spot size of the beam. The eighth single lens (12) is used to precisely control the focal position and converge the beam energy onto the photosensitive surface of the detector of the optical system. At this time, the detector receives the focused imaging beam, converts it into an electrical signal and transmits it to the data processing module. Combined with the multi-aperture stitching method, a high-resolution, large-field-of-view image of the target is formed, and the positioning and imaging of the space remote sensing target are completed.

5. The calibration method implemented by the space remote sensing target positioning optical system based on multi-aperture imaging according to claim 1, characterized in that, The detector has a pixel size of 9.

76. 。 6. The calibration method implemented by the space remote sensing target positioning optical system based on multi-aperture imaging according to claim 1, characterized in that, The method for calibrating the parallel beam stabilized by the fast-reflecting mirror (8) in step four includes the following steps: S4.1, Preliminary convergence of the fifth single lens (9): Using positive optical power, the parallel beam is converted into a low-convergence convergent beam. According to the output beam aperture of the front telescope group, the convex curvature radius of the fifth single lens (9) is adjusted to ensure that the beam has no obvious edge scattering; S4.2, Aberration correction of the sixth single lens (10): The spherical aberration and axial chromatic aberration introduced by the fifth single lens (9) are offset by negative optical power. The wavefront curvature of the beam is detected to ensure that there is no obvious distortion; S4.3, Enhanced convergence of the seventh single lens (11): Using higher than The optical power of the fifth single lens (9) compresses the beam spot size to within 1.2 times the detector pixel size; S4.4, the eighth single lens (12) focuses precisely: adjust the curvature of the meniscus structure of the eighth single lens (12) to match the wavefront curvature of the output beam of the seventh single lens (11) to ensure that the beam focus falls strictly in the center area of ​​the detector's photosensitive surface, while detecting the energy concentration of the spot, correcting residual field distortion, and ensuring consistent imaging resolution of the detector across the entire field of view; input the focused test beam into the detector, monitor its efficiency in converting optical signals into electrical signals, verify the stability of the electrical signal transmission to the data processing module, and ensure that there is no signal loss or distortion.

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