Wavefront correction method and device, computer storage medium and computer program product

Abstract

The embodiment of the invention provides a wavefront correction method and device, a computer storage medium and a computer program product. The method comprises the steps that a light spot image corresponding to a detection light beam is acquired; determining parameters of a target polynomial corresponding to the light spot image; generating a deflection angle instruction of a micromirror in a digital micromirror array according to the parameters of the target polynomial, sending the deflection angle instruction to the digital micromirror array to enable the digital micromirror array to adjust the posture of the micromirror according to the deflection angle instruction, and performing wavefront correction on a communication beam through the adjusted posture of the micromirror; the detection light beam and the communication light beam are obtained by performing two-path segmentation on an incident distorted light beam.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a wavefront correction method, device, computer storage medium, and computer program product. Background Technology

[0002] Laser communication is widely used for high-speed data transmission between space and ground due to its advantages such as high bandwidth and low power consumption. However, due to factors such as atmospheric disturbance and thermal deformation of the system itself, wavefront distortion occurs during light propagation, affecting communication quality and stability. Therefore, real-time correction of the wavefront of the communication beam has become an important technical direction for improving the performance of space-to-ground laser communication.

[0003] In related technologies, adaptive optics (AO) systems are often used for wavefront correction. However, AO systems suffer from correction delays, making it difficult to meet real-time communication requirements. Summary of the Invention

[0004] This application provides a wavefront correction method, apparatus, computer storage medium, and computer program product.

[0005] The technical solution of this application embodiment is implemented as follows: This application provides a wavefront correction method, the method comprising: Acquire the spot image corresponding to the probe beam; Determine the parameters of the target polynomial corresponding to the light spot image; The deflection angle command of the micromirrors in the digital micromirror array is generated according to the parameters of the target polynomial. The deflection angle command is sent to the digital micromirror array, so that the digital micromirror array adjusts the micromirror attitude according to the deflection angle command, and performs wavefront correction on the communication beam through the adjusted micromirror attitude. The detection beam and the communication beam are obtained by splitting the incident distorted beam into two paths.

[0006] This application provides a wavefront correction device, including: a beam splitter, a photoelectric conversion device, a processor, and a digital micromirror array, wherein: The beam splitter is used to split the incident distorted beam into two paths to obtain a detection beam and a communication beam. The photoelectric conversion device is used to acquire a light spot image corresponding to the detection beam and transmit the light spot image to the processor; The processor is configured to acquire a light spot image transmitted by the photoelectric conversion device, determine the parameters of a target polynomial corresponding to the light spot image, generate a deflection angle command for the micromirrors in the digital micromirror array based on the parameters of the target polynomial, and send the deflection angle command to the digital micromirror array. The digital micromirror array is used to adjust the micromirror attitude according to the deflection angle command, and to perform wavefront correction on the communication beam using the adjusted micromirror attitude.

[0007] This application provides a computer storage medium storing a computer program; when the computer program is executed, it can implement the wavefront correction method provided by one or more of the aforementioned technical solutions.

[0008] This application provides a computer program product, including a computer program that, when executed by a processor, implements the wavefront correction method provided by one or more of the aforementioned technical solutions.

[0009] The wavefront correction method provided in this application splits the incident distorted beam into two paths, resulting in a probe beam and a communication beam. The probe beam is primarily used for wavefront distortion detection, while the communication beam is mainly used for communication. This allows for parallel processing of distortion detection and communication tasks, effectively reducing processing latency. Furthermore, this application achieves wavefront correction by driving the deflection of micromirrors in a digital micromirror array. The micromirrors in the digital micromirror array are electrostatically driven, resulting in a faster response speed compared to traditional mechanical deformable mirrors, further reducing processing latency. Moreover, since the communication link and the probe link are separate links, the interference problem between wavefront distortion detection and communication caused by using a single link in related technologies can be avoided, improving the stability and anti-interference capability of the communication link. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure of a wavefront correction device provided in an embodiment of this application; Figure 2 This is a schematic diagram of another wavefront correction device provided in an embodiment of this application; Figure 3 A schematic flowchart of a wavefront correction method provided in an embodiment of this application; Figure 4 This is a flowchart illustrating another wavefront correction method provided in an embodiment of this application. Detailed Implementation

[0011] The technical solutions in this application will now be clearly and completely described with reference to the accompanying drawings.

[0012] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments provided herein are merely illustrative of the present application and are not intended to limit the present application. Furthermore, the embodiments provided below are some embodiments for implementing the present application, and not all embodiments for implementing the present application. Unless otherwise specified, the technical solutions described in the present application can be implemented in any combination. It should be noted that, in the embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a method or system that includes a list of elements includes not only the elements expressly described, but also other elements not expressly listed, or elements inherent to implementing the method or system. Without further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other related elements (e.g., steps in the method or units in the system, such as a portion of a processor, a portion of a program, or software, etc.) in the method or system that includes that element.

[0013] For example, the wavefront correction method provided in the embodiments of this application includes a series of steps, but the wavefront correction method provided in the embodiments of this application is not limited to the steps described. Similarly, the wavefront correction device provided in the embodiments of this application includes a series of modules, but the wavefront correction device provided in the embodiments of this application is not limited to the modules explicitly described, and may also include devices that need to be set up to obtain relevant information or to process based on the information.

[0014] In the following description, the terms first / second are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that first / second may be interchanged in a particular order or sequence where permissible, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0016] Currently, in satellite-to-ground laser communication, wavefront distortion caused by atmospheric turbulence severely degrades beam quality. The core of traditional adaptive optics (AO) systems is to monitor and correct the wavefront (the propagation path of light) of the optical system in real time to counteract external disturbances (such as atmospheric turbulence, mechanical vibration, thermal deformation, etc.). This system typically includes components such as a wavefront sensor, a controller, and a deformable mirror. The wavefront sensor measures the distortion of the light wave, and the controller analyzes the distortion mode to drive the deformable mirror or adjustable optical elements to restore the wavefront to an ideal state. However, AO systems suffer from problems such as complex devices, large size and power consumption, and correction delays, making it difficult to meet the requirements of lightweight satellite payloads and real-time communication. The separate architecture of wavefront detection and correction in this system is the core reason for the delay, and the collaboration of multiple components increases the system failure rate. In addition, a single detection link is susceptible to communication signal noise interference, resulting in insufficient wavefront detection accuracy, which further limits the correction effect.

[0017] To address the aforementioned technical problems, the following embodiments are proposed.

[0018] In some embodiments of this application, the wavefront correction method can be implemented according to a processor in the wavefront correction device. The processor can be at least one of the following: Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), CPU, controller, microcontroller, and microprocessor.

[0019] For example, see Figure 1 In addition to the processor 102, the wavefront correction device 10 also includes a beam splitter 100, a photoelectric conversion device 101, and a digital micromirror array 103.

[0020] For example, the beam splitter 100 can be a beam splitter or a beam splitter mirror, used to split the incident distorted beam into two paths to obtain a probe beam and a communication beam. It should be noted that the embodiments of this application do not specifically limit the division ratio of the communication beam and the probe beam, as long as the proportion of the communication beam is greater than that of the probe beam. For example, a 95:5 ratio can be used, that is, the communication beam accounts for 95% and the probe beam accounts for 5%, which will be used as an example in the following description. Other ratios can also be used, such as a 90:10 ratio or an 80:20 ratio.

[0021] In this embodiment of the application, a beam splitter can be used to achieve physical isolation between the two optical paths, wherein the optical path corresponding to the probe beam is the probe optical path, and the optical path corresponding to the communication beam is the communication optical path.

[0022] For example, see Figure 2 The detection optical path can integrate a photoelectric conversion device, which is used to acquire the spot image corresponding to the detection beam and transmit the spot image to the processor. For example, the photoelectric conversion device can be a high-speed complementary metal-oxide-semiconductor (CMOS) sensor, which will be used as an example in the following explanation. Other types of photoelectric conversion devices can also be used, such as charge-coupled device (CCD) sensors, etc., without specific limitations here. The communication optical path directly connects to the digital micromirror array and the communication receiver, and has both signal demodulation and wavefront correction functions.

[0023] It can be seen that, Figure 2 The design shown is an integrated optoelectronic and computational design, eliminating optical path interference introduced by a single link while ensuring parallel processing of communication signal transmission and wavefront detection, thus reducing processing latency. In practical applications, the optoelectronic conversion device, processor, and digital micromirror array can be integrated into the same processing unit, resulting in a more lightweight layout. This overcomes the limitations of traditional AO systems, providing a lightweight, low-latency wavefront correction solution for space-to-ground laser communication, thereby improving link stability and communication quality.

[0024] In this embodiment, the processor is used to acquire the light spot image transmitted by the photoelectric conversion device, determine the parameters of the target polynomial corresponding to the light spot image, generate the deflection angle command of the micromirrors in the digital micromirror array according to the parameters of the target polynomial, and send the deflection angle command to the digital micromirror array; the digital micromirror array is used to adjust the micromirror attitude according to the deflection angle command, and perform wavefront correction on the communication beam through the adjusted micromirror attitude.

[0025] It should be noted that the processor is the computational core of the entire system, undertaking the entire processing tasks of wavefront reconstruction, correction calculation, and dynamic optimization. Its innovation lies in the dynamic order selection mechanism, which can automatically adjust the fitting order of the Zernike polynomial according to the real-time turbulence intensity; correspondingly, a low-order polynomial is used to reduce computational complexity under weak turbulence conditions, while a high-order polynomial can be used under strong turbulence conditions to ensure correction accuracy; at the same time, optimization is performed in real time based on the performance feedback of the communication receiver.

[0026] Digital micromirror arrays (DMIs) are used to achieve non-mechanical wavefront compensation. Their technological breakthroughs are mainly reflected in three aspects: micromirror deflection accuracy reaches 0.1° with a response time of less than 20μs; they support pixel-level control, enabling the formation of high-resolution phase modulation surfaces; and they have a built-in redundant fault-tolerant design, automatically activating adjacent micromirrors for collaborative compensation when a single micromirror fails. Compared to traditional deformable mirrors, the solid-state deflection characteristics of DMIs compress mechanical delays from milliseconds to microseconds, meeting the stringent real-time requirements of space-to-ground laser communication.

[0027] To make it easier to understand, the following is... Figure 1 , Figure 2 Based on this, the wavefront correction method provided in the embodiments of this application will be described by way of example.

[0028] Figure 3 This is a flowchart illustrating a wavefront correction method provided in an embodiment of this application, as shown below. Figure 3 As shown, the process may include: Step 300: Obtain the spot image corresponding to the probe beam.

[0029] In practice, the probe beam is obtained by splitting the incident distorted beam into two paths using a beam splitter. The probe beam is used for subsequent wavefront detection and wavefront phase reconstruction. Here, the beam splitter can be a prism, beam splitter, etc., without specific limitations.

[0030] For example, by splitting the incident distorted beam using a beam splitter, in addition to obtaining a probe beam, a communication beam can also be obtained; that is, the probe beam and the communication beam are obtained by splitting the incident distorted beam into two paths; for example, 95% of the communication beam and 5% of the probe beam can be obtained; wherein, the communication beam is used for subsequent correction.

[0031] In this embodiment of the application, after the incident distorted beam is split into a probe beam by a beam splitter, a photoelectric conversion device integrated in the probe beam path for collecting the intensity distribution of the light spot can be used, such as a high-speed CMOS sensor, to collect the light spot image corresponding to the probe beam in real time and transmit the collected light spot image to the processor. At this time, the processor can obtain the light spot image corresponding to the probe beam.

[0032] A laser beam spot image is an image of the intensity distribution of a laser beam on a detection surface, acquired by a photoelectric conversion device. The spot image reflects the wavefront distortion caused by atmospheric disturbances or other factors. For example, when the laser beam spot on the detection surface is offset or deformed, it indicates the presence of aberrations such as tilt or defocus; when the laser beam spot on the detection surface is blurred and the edges are diffused, it may indicate the presence of higher-order aberrations.

[0033] To improve the detection accuracy of the spot image, this application embodiment also introduces a solar stray light suppression unit. That is, in addition to the beam splitter, the beam splitter may also include a solar stray light suppression unit. The solar stray light suppression unit includes a narrowband filter (the center wavelength can be 1550nm±0.5nm, which is not specifically limited here) and a polarization beam splitter component to filter out most of the background stray light, thereby improving the signal-to-noise ratio and ensuring the quality of the spot image.

[0034] It should be noted that when the photoelectric conversion device is a high-speed CMOS sensor, there are no specific limitations on the resolution and frame rate of the high-speed CMOS sensor. To ensure high-speed imaging effect, the resolution can be greater than or equal to 1280×1024 and the frame rate can be greater than or equal to 10kHz. For example, a high-speed CMOS sensor with a resolution of 1280×1024 and a frame rate of 10kHz can be used.

[0035] Understandably, in satellite-to-ground communication systems, atmospheric turbulence can cause phase distortion of the laser light incident on the ground receiver. To correct these distortions in a timely manner, a beam splitter can be used to split the incident light, separating a portion of it into a probe beam. After the probe beam is separated, a high-speed CMOS sensor captures it in real time, forming a spot image. This spot image is then transmitted to a processor for subsequent wavefront phase reconstruction.

[0036] As can be seen from the embodiments of this application, by acquiring the spot image in real time, the wavefront information can be updated rapidly, so that the system can meet the requirements for low-latency correction in the star-to-ground laser communication scenario.

[0037] Step 301: Determine the parameters of the target polynomial corresponding to the spot image.

[0038] In this embodiment of the application, after the processor acquires the spot image corresponding to the probe beam, it can determine the parameters of the target polynomial corresponding to the spot image.

[0039] For example, the target polynomial is a mathematical description of the wavefront distortion represented by the spot image; the target polynomial can be a Zernike polynomial, a polynomial modified based on the Zernike polynomial, or other mathematical expressions that can represent wavefront distortion, without specific limitations here; the Zernike polynomial will be used as an example for explanation later; it should be noted that when the target polynomial is a Zernike polynomial, the polynomial can represent different aberration types such as Piston, Tilt, Defocus, Astigmatism, and Coma.

[0040] The target polynomial can include parameters and a fitting order, both of which are used to describe the wavefront distortion corresponding to the spot image. When the target polynomial is a Zernike polynomial, the parameters can be Zernike coefficients, i.e., weight values ​​in the Zernike polynomial expansion, with each Zernike coefficient corresponding to a specific aberration type. The fitting order reflects the complexity of the aberration pattern; the higher the order, the more refined the corresponding aberration pattern. The determination process of the target polynomial will be illustrated in the following sections.

[0041] Step 302: Generate the deflection angle command of the micromirrors in the digital micromirror array according to the parameters of the target polynomial, send the deflection angle command to the digital micromirror array, so that the micromirrors in the digital micromirror array adjust their attitude according to the deflection angle command, and perform wavefront correction on the communication beam through the adjusted micromirror attitude.

[0042] Among them, the digital micromirror array is an optical modulator containing a large number of independently controllable micromirrors. Each micromirror can quickly adjust its angle relative to the incident light through a driving circuit, achieving dynamic compensation of the light wavefront.

[0043] In this embodiment of the application, after the processor obtains the parameters of the target polynomial corresponding to the spot image according to the above steps, it can use the Least Mean Square (LMS) algorithm or other related algorithms to calculate the parameters of the target polynomial and obtain the deflection angle command of the micromirrors in the digital micromirror array.

[0044] For example, after obtaining the deflection angle command of the micromirrors in the digital micromirror array, the deflection angle command can be sent to the digital micromirror array, so that the digital micromirror array adjusts the micromirror attitude according to the deflection angle command, and performs wavefront correction on the communication beam through the adjusted micromirror attitude.

[0045] Understandably, by adjusting the orientation of each micromirror to correct the wavefront of the communication beam, the distorted wavefront can be restored to an ideal plane wave.

[0046] For example, the deflection accuracy of each micromirror in the digital micromirror array reaches 0.1°, and the response time is less than 20μs; it supports... Continuous phase modulation to adapt to different turbulence distortion amplitudes (maximum corrected wavefront error less than...) , The digital micromirror array (DMI) supports pixel-level control, enabling the formation of high-resolution phase modulation surfaces. Furthermore, it supports pixel-level phase modulation to adapt to varying distortion amplitudes caused by turbulence. The DMI also incorporates a redundant fault-tolerant design; when a single micromirror fails, adjacent micromirrors automatically compensate to prevent the amplification of local distortion and improve system fault tolerance. Compared to traditional deformable mirrors, the solid-state deflection characteristics of the DMI compress mechanical delay from milliseconds to microseconds, meeting the stringent real-time requirements of space-to-ground laser communication.

[0047] As can be seen, in this embodiment, by splitting the incident distorted beam into two paths, a probe beam and a communication beam can be obtained. Thus, the probe beam is mainly used for wavefront distortion detection, while the communication beam is mainly used for communication. This allows for parallel processing of distortion detection and communication tasks, effectively reducing processing latency. Furthermore, this embodiment achieves wavefront correction by driving the micromirrors in the digital micromirror array to deflect. The micromirrors in the digital micromirror array are electrostatically driven, resulting in a faster response speed compared to traditional mechanical deformable mirrors, further reducing processing latency. Moreover, since the communication link and the probe link are separate links, the interference problem between wavefront distortion detection and communication caused by using a single link in related technologies can be avoided, improving the stability and anti-interference capability of the communication link.

[0048] In some embodiments, generating the deflection angle command of the micromirrors in the digital micromirror array based on the parameters of the target polynomial may include: determining a compensation value for the wavefront distortion of the probe beam based on the parameters of the target polynomial; and generating the deflection angle command of the micromirrors in the digital micromirror array based on the compensation value. For ease of understanding, the LMS algorithm is used as an example below to illustrate the process of generating the deflection angle command.

[0049] For example, after obtaining the target polynomial, the compensation value for the wavefront distortion of the probe beam can be determined based on the parameters of the target polynomial, such as the Zernike coefficients of the Zernike polynomial. Correspondingly, the Zernike coefficients can be adjusted. The difference between the error and the target coefficient (which is usually zero, representing no phase difference) is used to obtain the compensation value for wavefront distortion, i.e., the error. This compensation value is the input of the LMS algorithm. By iteratively adjusting the filter weights inside the LMS algorithm, the above compensation value is minimized to ensure that the corrected wavefront is exactly the opposite of the wavefront distortion, i.e., the corrected wavefront is close to the ideal plane wave. After obtaining the adjusted weights, the deflection angle corresponding to the weights can be obtained by looking up tables or formulas, and then the deflection angle command of the micromirrors in the digital micromirror array can be generated based on the deflection angle.

[0050] As can be seen, in this embodiment of the application, the LMS algorithm can be used to perform reverse compensation calculation on the reconstructed wavefront distortion. The deflection angle of each micromirror in the digital micromirror array is adjusted by the processor generating the deflection angle command, thereby realizing real-time compensation of the wavefront phase.

[0051] In practical implementation, the real-time performance of the LMS algorithm can also be optimized in the following ways, such as optimizing the floating-point algorithm (64-bit) for wavefront phase calculation into a fixed-point algorithm (16-bit), and controlling the accuracy loss to not exceed 0.1% through error compensation algorithms, etc., without making specific limitations here.

[0052] The process of determining the parameters of the target polynomial corresponding to the spot image is illustrated below.

[0053] In some embodiments, determining the parameters of the target polynomial corresponding to the spot image may include: determining the wavefront slope of the spot image; and determining the parameters of the target polynomial based on the wavefront slope.

[0054] In this embodiment, after acquiring the spot image, the processor can directly determine the wavefront slope of the spot image, or it can preprocess the spot image first and then determine the wavefront slope of the preprocessed spot image. The purpose of preprocessing is to improve image quality to ensure the accuracy of subsequent processes. For example, preprocessing can be noise reduction processing of the spot image to remove sensor noise and background light interference, or it can be other preprocessing operations, which are not specifically limited here.

[0055] For example, after determining the wavefront slope of the light spot image, the parameters of the target polynomial can be determined based on the wavefront slope.

[0056] In this embodiment of the application, by determining the wavefront slope of the light spot image, the deformation characteristics of the light spot image can be accurately captured, thereby providing a reliable data basis for subsequent wavefront compensation.

[0057] In some optional embodiments, determining the wavefront slope of the spot image may include: segmenting the spot image to obtain multiple sub-apertures; determining the spot centroid offset of each sub-aperture; and determining the wavefront slope based on the spot centroid offsets of the multiple sub-apertures.

[0058] For example, after obtaining the spot image or the preprocessed spot image, the processor can first segment it to obtain multiple sub-apertures; where each sub-aperture represents the propagation path information of the probe beam within a certain local range; this segmentation method can improve the accuracy of subsequent wavefront calculations and reduce computational complexity.

[0059] Here, there is no specific limit to the number of sub-apertures. For example, the spot image can be divided into a 32×32 sub-aperture array to cover the entire spot area.

[0060] For example, after obtaining multiple sub-apertures, the centroid offset of the light spot in each sub-aperture can be determined; whereby the centroid offset refers to the degree of displacement of the light spot center relative to the ideal position within each sub-aperture. The centroid offset reflects the local wavefront tilt and is the basis for calculating the wavefront slope. Here, the method for determining the centroid offset is not specifically limited.

[0061] For example, after obtaining the centroid offset of the light spot for each sub-aperture, the centroid offset of the light spot for multiple sub-apertures can be estimated using methods such as gradient method or finite difference method to obtain wavefront slope; then, the parameters of the target polynomial corresponding to the light spot image can be determined based on the wavefront slope.

[0062] In this embodiment, by segmenting the spot image into multiple sub-apertures and calculating the centroid offset of each sub-aperture separately, wavefront distortion information can be extracted more precisely. This method of segmenting the spot image into multiple sub-apertures and calculating the centroid offset of each sub-aperture separately improves the accuracy of wavefront slope calculation and ensures better fitting of the subsequent Zernike polynomial.

[0063] In some embodiments, determining the parameters of the target polynomial based on the wavefront slope may include: using a phase reconstruction algorithm to reconstruct the wavefront phase of the wavefront slope to obtain the wavefront phase distribution; and performing polynomial fitting on the wavefront phase distribution to obtain the parameters of the target polynomial.

[0064] For example, after obtaining the wavefront slope, the processor can use a phase reconstruction algorithm to reconstruct the wavefront phase from the wavefront slope to obtain the wavefront phase distribution.

[0065] In practical applications, phase reconstruction algorithms can be built into processors to achieve high-speed, real-time calculation of wavefront distortion. Here, a phase reconstruction algorithm is a method for converting wavefront slope information into a complete wavefront phase distribution. Phase reconstruction algorithms are typically based on the gradient integral principle; by integrating the wavefront slope, the wavefront phase distribution of the entire beam can be reconstructed.

[0066] The wavefront phase distribution describes the phase difference at various points during the propagation of the light wave, reflecting whether the beam is in an ideal plane wave state. The wavefront phase distribution is the fundamental data for subsequent polynomial fitting, reflecting wavefront distortion caused by factors such as atmospheric turbulence and mechanical vibration.

[0067] In this embodiment of the application, after obtaining the wavefront phase distribution, polynomial fitting can be performed on the wavefront phase distribution to obtain the parameters of the target polynomial.

[0068] Polynomial fitting is a method that decomposes complex wavefront distortion into a series of orthogonal basis functions. For example, Zernike polynomials can characterize various types of aberrations, such as translation, tilt, defocus, and coma.

[0069] In practical applications, by performing polynomial fitting on the wavefront phase distribution, the weight coefficients of each basis function can be obtained, which are the parameters of the target polynomial; these parameters can be used to quantify the characteristics of wavefront distortion.

[0070] For example, when the target polynomial is a Zernike polynomial, the parameters, i.e., the Zernike coefficients, are a set of values ​​used to represent the contribution of a Zernike polynomial of a specific order to the wavefront. The smaller the parameters, the closer the wavefront is to the ideal state; conversely, the larger the parameters, the more severe the wavefront distortion.

[0071] For example, see formula (1), by analyzing the wavefront phase distribution By performing polynomial fitting, the parameters of the target polynomial can be obtained. .

[0072] (1) in, This refers to the j-th order parameter, which characterizes the distortion amplitude; This refers to basis functions. Represents the normalized radial coordinates. Indicates azimuth; This indicates the fitting order.

[0073] In this embodiment of the application, by using a phase reconstruction algorithm to reconstruct the wavefront slope and performing polynomial fitting on the wavefront phase distribution, the characteristics of wavefront distortion can be accurately described, thereby effectively supporting subsequent dynamic correction operations.

[0074] In some embodiments, performing polynomial fitting on the wavefront phase distribution to obtain the parameters of the target polynomial may include: analyzing and processing the spot image to obtain the turbulence intensity; determining the fitting order corresponding to the spot image based on the turbulence intensity; and performing polynomial fitting on the wavefront phase distribution based on the fitting order to obtain the parameters of the target polynomial.

[0075] Turbulence intensity refers to a quantitative index of wavefront distortion calculated from the spot image, used to measure the level of phase distortion caused by atmospheric turbulence or other interference factors during beam propagation.

[0076] For example, by analyzing and processing the spot image, information reflecting wavefront distortion can be obtained, such as wavefront slope, spot size, and spot intensity. Based on this information, the turbulence intensity can be estimated.

[0077] For example, turbulence intensity can be determined by the atmospheric refractive index structure constant. Characterization, hereinafter referred to as constant Constants can be pre-built. A mapping library between fitting order and constants, which includes constants. The multiple value intervals and the fitting order corresponding to each value interval.

[0078] It should be noted that different fitting orders correspond to different aberration types and basis functions. There are differences; Table 1 shows the aberration types corresponding to fitting orders ranging from 1 to 8. .

[0079]

[0080] Table 1 In one embodiment, the multiple value ranges may include the following three different value ranges: weak turbulence value range , turbulence value range and the range of values ​​for strong turbulence .

[0081] It should be noted that the fitting order corresponding to different value ranges can be set according to the actual situation, and the embodiments of this application do not impose specific limitations on this; for example, the value range of weak turbulence The corresponding fitting order can be 6; in this case, the target polynomial can be a 6th-order polynomial, covering low-order distortions such as translation, tilt, and defocus, with the lowest computational cost; the medium turbulence value range The corresponding fitting order can be 15; in this case, the target polynomial can be a 15th-order polynomial, covering distortions such as increased coma and spherical aberration, thus balancing accuracy and efficiency; the strong turbulence value range The corresponding fitting order can be 36. At this time, the target polynomial can be a 36th order polynomial, which has a high correction accuracy, up to 90%. At the same time, it can be computed in parallel through FPGA cores (pipeline processing of wavefront reconstruction and instruction generation), with the highest computational load.

[0082] It can be seen that the fitting order of the target polynomial can be dynamically determined according to the turbulence intensity. For example, a 6th-order polynomial is used under weak turbulence conditions, while a 36th-order polynomial can be used under strong turbulence conditions to ensure the correction accuracy.

[0083] For example, as can be seen from the above, after obtaining the fitting order, the processor can determine the corresponding basis function according to the mapping relationship shown in Table 1 above. Then, based on the fitting order and the corresponding basis function, the wavefront phase distribution is fitted with a polynomial to obtain the parameters of the target polynomial.

[0084] As can be seen, in this embodiment of the application, by dynamically selecting the fitting order of the target polynomial according to the turbulence intensity, the problem of resource waste or insufficient accuracy caused by a fixed order can be avoided; by dynamically adjusting the order of the target polynomial to perform polynomial fitting on the wavefront phase distribution, the computational efficiency can be optimized while ensuring the wavefront correction accuracy, and the wavefront correction under different turbulence intensities can be flexibly adapted.

[0085] In some embodiments, the above method may further include: acquiring a first performance parameter corresponding to the communication beam or a second performance parameter corresponding to the detection beam; adjusting the fitting order corresponding to the spot image according to the first performance parameter or the second performance parameter; and performing polynomial fitting on the wavefront phase distribution based on the adjusted fitting order.

[0086] Here, the first performance parameter is a measurement index for the communication beam, which may include one or more of the bit error rate and signal-to-noise ratio. The second performance parameter is a measurement index for the probe beam, which may include the beam sharpness, etc.

[0087] For example, after wavefront correction, the communication beam is focused onto the communication receiver by the main lens, and the processor can collect the first performance parameter or the second performance parameter in real time or at regular intervals; then, based on the collected first performance parameter or the second performance parameter, the fitting order corresponding to the spot image is adjusted.

[0088] As discussed above, the fitting order determines the complexity and accuracy of the target polynomial. A higher fitting order allows the target polynomial to capture more complex distortion patterns, but also consumes more computational resources; a lower order results in higher computational efficiency, but may sacrifice some correction accuracy.

[0089] In this embodiment, the processor can automatically select the most suitable fitting order based on the collected first or second performance parameters to achieve the best balance between computational efficiency and correction accuracy. For example, under weak turbulence conditions, the system can select a lower order (such as the 6th order) to reduce the computational burden; while under strong turbulence conditions, it can be increased to a higher order (such as the 15th or even the 36th order) to improve the correction accuracy.

[0090] It should be noted that the LMS algorithm can be automatically optimized based on the first or second performance parameters collected to ensure the correction effect.

[0091] As can be seen from the embodiments of this application, by collecting performance parameters and adjusting the fitting order, a closed-loop feedback mechanism can be formed, and a complete closed-loop control mechanism of detection-calculation-correction-feedback can be constructed, which further improves the correction accuracy and system robustness.

[0092] In some embodiments, adjusting the fitting order of the spot image according to a first performance parameter or a second performance parameter may include: adjusting the fitting order of the spot image according to a comparison result of the first performance parameter and a first threshold; or, adjusting the fitting order of the spot image according to a comparison result of the second performance parameter and a second threshold. The first performance parameter may include one or more of bit error rate and signal-to-noise ratio, and the second performance parameter may include spot sharpness.

[0093] Here, the first threshold can be a benchmark value pre-set for the first performance parameter, and the embodiments of this application do not specifically limit its value; for example, the first performance parameter includes the bit error rate, and the first threshold is 10. -4 In the case where the bit error rate is greater than 10 -4 When the error rate is less than or equal to 10, it indicates a deterioration in communication quality. In this case, it is necessary to improve the wavefront correction accuracy. For example, the fitting order of the target polynomial can be increased, the LMS algorithm can be optimized, or both can be performed simultaneously. -4 When the first performance parameter is the signal-to-noise ratio, it indicates good communication quality. In this case, the fitting order of the objective polynomial can be reduced to save computational resources. When the first performance parameter includes the signal-to-noise ratio, the corresponding process is similar, and will not be repeated here to avoid repetition.

[0094] Here, the second threshold can be a benchmark value pre-set for the second performance parameter. The embodiments of this application do not specifically limit its value. For example, its value can be 0.6, 0.7, etc. For example, when the second performance parameter includes spot sharpness and the second threshold is 0.6, when the spot sharpness is less than 0.6, it indicates that the communication quality has deteriorated. At this time, it is necessary to improve the wavefront correction accuracy. For example, the fitting order of the target polynomial can be increased, or the LMS algorithm can be optimized, or both can be performed simultaneously. When the spot sharpness is greater than or equal to 0.6, it indicates that the communication quality is good. At this time, the fitting order of the target polynomial can be reduced to save computing resources.

[0095] For example, the LMS algorithm parameters can be optimized based on the first or second performance parameters to form a closed-loop feedback system, ensuring that the device is always in the optimal working state.

[0096] In this embodiment, by dynamically adjusting the order of the target polynomial through performance parameters, the system can flexibly cope with wavefront distortion under different atmospheric disturbance conditions, thereby improving the anti-interference and adaptive capabilities of the satellite-to-ground laser communication link.

[0097] This application embodiment integrates wavefront detection and dynamic correction of digital micromirror arrays, eliminating the complex structure of independent sensors, controllers, and deformable mirrors in traditional AO systems. This allows wavefront detection and correction to be processed in parallel within the same data processing module, significantly reducing system size and power consumption, achieving lightweight and low latency, and effectively improving the stability and anti-interference capability of the space-to-ground laser communication link.

[0098] Figure 4 A flowchart illustrating another wavefront correction method provided in this application embodiment is shown below. Figure 4 As shown, the process may include: Step 400: Acquisition of light spot image.

[0099] For example, the spot image corresponding to the probe beam can be acquired in real time for wavefront reconstruction by a photoelectric conversion device (high-speed CMOS sensor with resolution ≥1280×1024 and frame rate ≥10kHz) integrated into the probe optical path.

[0100] Step 401: Sub-aperture segmentation.

[0101] For example, after obtaining the spot image, the photoelectric conversion device sends it to the processor, which then performs sub-aperture segmentation. For instance, the spot image can be segmented into M×N sub-apertures (such as a 32×32 array).

[0102] Step 402: Calculate the centroid offset of the light spot.

[0103] For example, after obtaining the segmented sub-apertures, the processor continues to determine the centroid offset of the spot for each sub-aperture.

[0104] Step 403: Determine the wavefront slope.

[0105] For example, after obtaining the centroid offset of the light spot for each sub-aperture, the wavefront slope is determined based on the centroid offsets of the light spots for multiple sub-apertures.

[0106] Step 404: Parameter determination.

[0107] For example, the parameters of the target polynomial corresponding to the spot image are determined based on the wavefront slope.

[0108] Step 405: Deflection angle command generated.

[0109] For example, the processor uses the LMS algorithm to generate deflection angle instructions for each micromirror in the digital micromirror array based on the target polynomial.

[0110] Step 406: Closed-loop feedback optimization.

[0111] For example, the processor can acquire the first performance parameter corresponding to the communication beam or the second performance parameter corresponding to the detection beam in real time or at regular intervals; then, based on the acquired first performance parameter or second performance parameter, it can dynamically adjust the fitting order corresponding to the spot image, or optimize the LMS algorithm, or both simultaneously, to achieve closed-loop feedback optimization.

[0112] It should be noted that, in this embodiment, the functional modules of the wavefront correction device can be integrated into one processing unit, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional module.

[0113] If the integrated unit is implemented as a software functional module and is not sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment, in essence, or the part that contributes to related technologies, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the method of this embodiment. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0114] Specifically, the computer program instructions corresponding to a wavefront correction method in this embodiment can be stored on storage media such as optical discs, hard disks, and USB flash drives. When the computer program instructions corresponding to a wavefront correction method in the storage media are read or executed by a wavefront correction device, any one of the wavefront correction methods in the aforementioned embodiments is implemented.

[0115] In some embodiments, this application also provides a computer storage medium storing a computer program that, when executed by a processor, implements any of the wavefront correction methods described in the foregoing embodiments.

[0116] In some embodiments, this application also provides a computer program product, including a computer program that, when executed by a processor, implements any of the wavefront correction methods described in the foregoing embodiments.

[0117] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0118] The methods disclosed in the various method embodiments provided in this application can be arbitrarily combined to obtain new method embodiments without conflict.

[0119] The features disclosed in the various product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0120] The features disclosed in the various method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0121] Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, computer storage media, or computer program products. Therefore, this application can take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage) containing computer-usable program code.

[0122] This application is described with reference to flowchart illustrations or block diagrams of methods, apparatus, computer storage media, and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustration or block diagram, and combinations of blocks in the flowchart illustration or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart. Figure 1 One or more processes or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0123] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes or boxes Figure 1The steps of the function specified in one or more boxes.

[0124] The above are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application.

Claims

1. A wavefront correction method, characterized in that, The method includes: Acquire the spot image corresponding to the probe beam; Determine the parameters of the target polynomial corresponding to the light spot image; The deflection angle command of the micromirrors in the digital micromirror array is generated according to the parameters of the target polynomial. The deflection angle command is sent to the digital micromirror array, so that the digital micromirror array adjusts the micromirror attitude according to the deflection angle command, and performs wavefront correction on the communication beam through the adjusted micromirror attitude. The detection beam and the communication beam are obtained by splitting the incident distorted beam into two paths.

2. The method according to claim 1, characterized in that, The parameters for determining the target polynomial corresponding to the light spot image include: Determine the wavefront slope of the light spot image; The parameters of the target polynomial are determined based on the wavefront slope.

3. The method according to claim 2, characterized in that, Determining the parameters of the target polynomial based on the wavefront slope includes: The wavefront slope is reconstructed using a phase reconstruction algorithm to obtain the wavefront phase distribution. The parameters of the target polynomial are obtained by performing polynomial fitting on the wavefront phase distribution.

4. The method according to claim 2 or 3, characterized in that, Determining the wavefront slope of the light spot image includes: The light spot image is segmented to obtain multiple sub-apertures; Determine the centroid offset of the light spot for each sub-aperture; The wavefront slope is determined based on the centroid offset of the multiple sub-apertures.

5. The method according to claim 3, characterized in that, The process of performing polynomial fitting on the wavefront phase distribution to obtain the parameters of the target polynomial includes: The turbulence intensity is obtained by analyzing and processing the light spot image; Based on the turbulence intensity, determine the fitting order corresponding to the spot image; Based on the fitting order, a polynomial fitting is performed on the wavefront phase distribution to obtain the parameters of the target polynomial.

6. The method according to claim 5, characterized in that, The method further includes: Collect the first performance parameter corresponding to the communication beam or the second performance parameter corresponding to the detection beam; Adjust the fitting order of the spot image according to the first performance parameter or the second performance parameter; The wavefront phase distribution is fitted using a polynomial based on the adjusted fitting order.

7. The method according to claim 6, characterized in that, The step of adjusting the fitting order corresponding to the spot image according to the first performance parameter or the second performance parameter includes: Based on the comparison result of the first performance parameter and the first threshold, adjust the fitting order corresponding to the spot image; or, Based on the comparison result of the second performance parameter and the second threshold, the fitting order corresponding to the spot image is adjusted; the first performance parameter includes one or more of the bit error rate and signal-to-noise ratio, and the second performance parameter includes spot sharpness.

8. The method according to claim 1, characterized in that, Generate deflection angle commands for the micromirrors in the digital micromirror array based on the parameters of the target polynomial, including: The compensation value for the wavefront distortion of the probe beam is determined based on the parameters of the target polynomial; The deflection angle command of the micromirrors in the digital micromirror array is generated based on the compensation value.

9. A wavefront correction device, characterized in that, include: Spectrometers, photoelectric conversion devices, processors, and digital micromirror arrays, among which: The beam splitter is used to split the incident distorted beam into two paths to obtain a detection beam and a communication beam. The photoelectric conversion device is used to acquire a light spot image corresponding to the detection beam and transmit the light spot image to the processor; The processor is configured to acquire a light spot image transmitted by the photoelectric conversion device, determine the parameters of a target polynomial corresponding to the light spot image, generate a deflection angle command for the micromirrors in the digital micromirror array based on the parameters of the target polynomial, and send the deflection angle command to the digital micromirror array. The digital micromirror array is used to adjust the micromirror attitude according to the deflection angle command, and to perform wavefront correction on the communication beam using the adjusted micromirror attitude.

10. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method described in any one of claims 1 to 8.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method described in any one of claims 1 to 8.

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