Method for eliminating the influence of slit diffraction on wavefront detection and spliced ​​telescope system

Abstract

The invention relates to the technical field of space telescopes, and specifically provides a method for eliminating the influence of slit diffraction on wavefront detection and a spliced ​​telescope system. The exit pupil surface phases of in-focus images and out-of-focus images are solved by a GS algorithm, and the solution accuracy of the system exit pupil surface phase is optimized under the premise that the defocus amount is known, and the optimized system exit pupil surface phase is used as an optimal estimated value; then, a target function for solving the system exit pupil surface phase is constructed by a PD algorithm, and the target function is solved by an L-BFGS algorithm, and the optimal estimated value obtained by the GS algorithm is used as an initial value of the target function to calculate the system exit pupil surface phase; and a high-precision exit pupil surface phase solution is achieved by cross-iteration of the GS algorithm and the PD algorithm, and the influence of the slit diffraction on the wavefront detection accuracy of the spliced ​​space telescope is effectively suppressed.

Description

Technical Field

[0001] The invention relates to the technical field of space telescopes, and specifically provides a method for eliminating the influence of slit diffraction on wavefront detection and a spliced ​​telescope system. Background Art

[0002] The development of a large-aperture space telescope will drive and lead the development of a number of related cutting-edge industries. It will not only enhance the original innovation capabilities of countries in the frontier fields of science, but also meet the economic development needs of countries. It is of great significance to further enhance the international status and international influence of countries.

[0003] There are two main types of existing large-aperture space telescopes: "integrated" space telescopes and "spliced" space telescopes. Due to the limitations of the whole machine's launch and other restrictions, the effective aperture of the "integrated" space telescope with a single mirror is difficult to further increase, and it is impossible to achieve ultra-large aperture applications. The "spliced" structure can effectively break through the aperture limit and is an important research direction for large-aperture space telescopes. The great success of the "James Webb Space Telescope" (JWST) has effectively demonstrated the superiority of the "spliced" space telescope.

[0004] In order to make the image quality of a spliced ​​space telescope and an integral space telescope of the same aperture have the same quality, active optical technology is needed to adjust the position of each spliced ​​sub-mirror and secondary mirror and other optical elements to make the system image quality close to the diffraction limit. Active optical technology includes three parts: wavefront detection, adjustment amount calculation and correction implementation. Among them, high-precision wavefront detection is the prerequisite for ensuring the image quality of the telescope.

[0005] However, due to the inherent slit diffraction of the spliced ​​space telescope, the image of the image spot is not only the far-field Fraunhofer diffraction of the pupil function, but also superimposed with the slit diffraction, forming a complex "starburst". This "starburst" effect will cause the grayscale value of some pixels in the image spot image to change, thereby affecting the solution of the wavefront phase. In the existing wavefront detection technology, it is mainly based on the Fraunhofer far-field diffraction principle, and the grayscale value of each pixel is used to solve the wavefront phase, but the influence of slit diffraction on the wavefront phase solution is not considered in this process. In addition, due to the superposition of slit diffraction and far-field Fraunhofer diffraction of pupil function, it is impossible to effectively distinguish the influence of slit diffraction and far-field Fraunhofer diffraction of pupil function on the grayscale value of a single pixel, which further reduces the accuracy of the system wavefront sensing.

[0006] Therefore, there is an urgent need for a method that can suppress the influence of slit diffraction on the wavefront detection accuracy of the spliced ​​space telescope. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a method for eliminating the influence of slit diffraction on wavefront detection, by cross-applying the GS (Gerchberg-Saxton) algorithm and the PD (Phase Diversity) algorithm to perform exit pupil phase recovery, and using an image processing method to improve the on-orbit wavefront detection accuracy of a spliced ​​space telescope, which can effectively suppress the influence of slit diffraction on the wavefront detection accuracy of the spliced ​​space telescope.

[0008] The method for eliminating the influence of slit diffraction on wavefront detection provided by the present invention comprises:

[0009] S1: Collect in-focus image spot images and out-of-focus image spot images;

[0010] S2: Solve the exit pupil phases of the in-focus image spot image and the out-focus image spot image respectively through the GS algorithm, and design the optimal estimate of the system exit pupil phase based on the defocus amount of the out-focus image spot image;

[0011] S3: Construct the objective function of the system exit pupil phase solution based on the PD algorithm, and use the best estimated value of the system exit pupil phase as the initial value to calculate the system exit pupil phase;

[0012] S4: Iterate the calculation of S2 and S3. A single iteration is:

[0013] The system exit pupil surface phase calculated by S3 is used as the initial random phase of the GS algorithm, and S2 is re-executed to calculate a new optimal estimated value of the system exit pupil surface phase; the new optimal estimated value of the system exit pupil surface phase is used as a new initial value for the PD algorithm, and S3 is re-executed;

[0014] When the iteration termination condition is met, the final system exit pupil phase is obtained.

[0015] Preferably, in S1, it further includes: filtering the in-focus image plane spot image and the out-focus image plane spot image by using a Gaussian filter mask to correct the pixel grayscale value.

[0016] Preferably, the intensity two-dimensional matrix of the in-focus image spot image after filtering is obtained. The intensity two-dimensional matrix of the defocused image plane spot image after filtering ,Will and Substitute them into the phase recovery model based on the GS algorithm to solve the two-dimensional phase matrix of the exit pupil surface of the in-focus image spot image The two-dimensional phase matrix of the exit pupil phase of the defocused image spot image .

[0017] Preferably, the best estimate of the system exit pupil phase is The calculation formula is:

[0018] ;

[0019] in, is the defocus amount of the defocused image point image.

[0020] Preferably, before constructing the objective function of the system exit pupil phase solution, it also includes: setting a pixel screening template according to the light intensity distribution law of the slit diffraction stripes of the space telescope, the pixel value at the slit diffraction stripe position is 0, and the pixel value at other positions is 1.

[0021] Preferably, the intensity two-dimensional matrix of the in-focus image spot image after filtering is The intensity two-dimensional matrix of the defocused image plane spot image after filtering The intensity two-dimensional matrix of the pixel screening template is obtained by respectively comparing it with the intensity two-dimensional matrix of the pixel screening template to obtain the intensity two-dimensional matrix of the in-focus image plane spot image after the pixel screening template is filtered. The intensity two-dimensional matrix of the defocused image spot image after being filtered by the pixel filtering template .

[0022] Preferably, the objective function of the system exit pupil phase solution is for:

[0023] ;

[0024] in, is the objective function The solution of is the exit pupil phase of the system to be solved, It represents the intensity two-dimensional matrix of any image point image after being filtered by the pixel filtering template, that is, and , represents the inverse Fourier transform, represents the system pupil, is an imaginary unit, represents the initial random phase, Represents the total number of selected image plane spot images, which is 2.

[0025] Preferably, the iteration termination condition is:

[0026] ;

[0027] in, represents the number of iterations, Indicates The system exit pupil phase calculated by the iteration is Indicates -1 Iteration calculated system exit pupil phase, is a constant set according to the wavefront detection accuracy.

[0028] A spliced ​​telescope system performs wavefront detection by eliminating the influence of slit diffraction on the wavefront detection accuracy of the telescope.

[0029] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0030] The present invention accurately obtains the system exit pupil phase of a spliced ​​space telescope by cross-application of the GS algorithm and the PD algorithm, and suppresses the inherent slit diffraction of the spliced ​​space telescope in the frequency domain through a Gaussian filter mask, thereby reducing the interference of the slit diffraction on the grayscale value of the effective pixel; the GS algorithm can quickly calculate the system exit pupil phase through two Fourier transforms, the pixel-level PD algorithm can eliminate the pixels affected by the slit diffraction, and use the remaining pixels to construct the system exit pupil phase solution objective function, and through the cross-iteration and complementary advantages of the GS algorithm and the pixel-level PD algorithm, the calculated system exit pupil phase accuracy can be greatly improved, and the influence of the inherent slit diffraction of the spliced ​​space telescope on the system wavefront sensing accuracy can be suppressed to the greatest extent, thereby effectively improving the wavefront detection accuracy of the spliced ​​space telescope.

[0031] In addition, there is currently a gap in research on suppressing the influence of slit diffraction on wavefront detection accuracy. There is a lack of methods in this field that can effectively eliminate the influence of slit diffraction inherent in spliced ​​space telescopes. The present invention fills this research gap and has positive significance for improving the accuracy of wavefront detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flow chart of a method for eliminating the influence of slit diffraction on wavefront detection provided in an embodiment of the present invention;

[0033] Figure 2 is a schematic diagram of a Gaussian filter mask provided according to an embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of a phase recovery model based on a GS algorithm provided according to an embodiment of the present invention;

[0035] Figure 4 is a layout diagram of a spliced ​​sub-mirror provided according to an embodiment of the present invention;

[0036] Figure 5 is a schematic diagram of an image plane spot image provided by an embodiment of the present invention;

[0037] Figure 6 is a schematic diagram of an image plane spot image after being screened by a pixel screening template provided by an embodiment of the present invention;

[0038] Figure 7It is an iterative flow chart of cross-application of the GS algorithm and the PD algorithm provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the invention clearer, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention and do not constitute a limitation to the invention. Similar components in different embodiments use associated similar component numbers. In the following embodiments, many detailed descriptions are to enable the invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other components, materials, and methods. In some cases, some operations related to the invention are not shown or described in the specification, in order to avoid the core part of the invention being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0041] In the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0042] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0043] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0044] Since the spliced ​​space telescope has inherent slit diffraction, and the mechanism of the influence of slit diffraction on the grayscale value of the image collected by the detector is complex and has many influencing factors, it is difficult to correct the grayscale value of the affected pixels through modeling and other methods to affect the impact of slit diffraction on the wavefront detection of the telescope system. In order to solve the above problem, in one embodiment of the present invention, a method for eliminating the influence of slit diffraction on the wavefront detection accuracy of the space telescope is provided, which combines the phase recovery principle based on the GS (Gerchberg-Saxton) algorithm with the phase recovery principle based on the phase difference (Phase Diversity, PD) algorithm to suppress the influence of slit diffraction on the wavefront detection accuracy of the spliced ​​space telescope and improve the on-orbit wavefront detection accuracy. Please refer to Figure 1 , the specific processing process is:

[0045] S1: Focusing is performed through a focusing mirror equipped with a spliced ​​space telescope, and multiple image plane spot images, namely, image plane PSF images, are acquired in a time-sharing manner through an image acquisition device. The acquired images need to include at least one in-focus image plane spot image (hereinafter referred to as the in-focus PSF image) and one out-of-focus image plane spot image (hereinafter referred to as the out-of-focus PSF image), wherein the defocus amount of the out-of-focus PSF image is a known amount.

[0046] The in-focus PSF image and the out-of-focus PSF image are quantitatively represented. Specifically, the intensity two-dimensional matrix of the in-focus PSF image is expressed as The intensity two-dimensional matrix of the defocused PSF image is represented by It means that the peak values ​​of the spot images of both are located at the center of the corresponding two-dimensional matrix, and the defocus amount (i.e., defocus aberration) of the defocus PSF image is , which is a known design value.

[0047] According to Fourier optical theory, there is the following relationship between the intensity two-dimensional matrix of the image plane PSF image and the two-dimensional matrix distribution of the exit pupil plane phase:

[0048] ;

[0049] in, Represents the intensity two-dimensional matrix of the image plane PSF image, is the image plane coordinate vector, represents the two-dimensional matrix distribution of the exit pupil phase, that is, the quantized two-dimensional matrix of the exit pupil phase, is the normalized pupil vector, represents the inverse Fourier transform, represents the system pupil, which is specifically determined by Axis and The two-dimensional matrix formed by the axis, if the matrix element is within the normalized pupil, the corresponding value is 1; if the matrix element is outside the normalized pupil, the corresponding value is 0. is an imaginary unit, is an exponential function with the natural constant e as base, The "starburst" is caused by slit diffraction and is a noise term.

[0050] For the "starburst" caused by slit diffraction, the embodiment of the present invention proposes to filter the in-focus PSF image and the out-of-focus PSF image through a Gaussian filter mask, correct the pixel grayscale value in the image, suppress the influence of slit diffraction on the pixel grayscale value, reduce noise and other non-ideal effects, and make the performance of the system closer to the ideal state. Please refer to Figure 2 The Gaussian filter mask shown in the figure shows that after Gaussian filtering, the two-dimensional matrix distribution of the image plane PSF image intensity is mainly affected by the phase distribution of the exit pupil surface, while the "starburst" noise caused by the slit diffraction is significantly reduced. The Gaussian filter mask can suppress the slit diffraction in the frequency domain, reduce the interference of the slit diffraction on the grayscale value of the effective pixels of the image plane image, and improve the accuracy of the subsequent calculation of the exit pupil surface phase by the GS algorithm. Therefore, the relationship between the two-dimensional matrix of the intensity of the image plane PSF image and the two-dimensional matrix distribution of the exit pupil surface phase can be expressed as:

[0051] ;

[0052] is the residual noise after filtering, which is much smaller than , so it can be directly ignored in actual calculations.

[0053] By using Figure 2 After filtering with the Gaussian filter mask shown, the two-dimensional intensity matrices of the in-focus PSF image and the out-of-focus PSF image are and .

[0054] S2: After filtering, first obtain the initial exit pupil phase value of the system based on the GS algorithm. Specifically, use Figure 3 The phase recovery model of the GS algorithm shown solves the two-dimensional matrix of the exit pupil phase of the in-focus PSF image and the out-of-focus PSF image and The phase recovery model based on the GS algorithm is an existing model, which is only directly referenced in the embodiments of the present invention. and Bring them into the existing GS algorithm model respectively. The general processing process of the GS algorithm is to select an initial random phase , combined with the system pupil (The relationship between the exit pupil surface phase two-dimensional matrix distribution and The same, the two are just different in the way of expression), the Fourier transform function of the pupil function in the image space is obtained by Fourier transform , is the amplitude of the image space after Fourier transformation, is the phase of the image space after Fourier transform, and then the above result is subjected to inverse Fourier transform (IFT):

[0055] ;

[0056] The phase of the initial phase distribution is replaced by the phase update after inverse Fourier transformation, and the amplitude information is retained; and the above process is iterated repeatedly until the algorithm converges, and the exit pupil surface phase two-dimensional matrix of the in-focus PSF image and the out-of-focus PSF image is output respectively. and .

[0057] Combined with the known defocus PSF image defocus amount , optimize and improve the accuracy of the system exit pupil phase solution, and use the high-precision system exit pupil phase after optimization calculation as the best estimate of the system exit pupil phase , and its calculation formula is:

[0058] .

[0059] S3: Solve the system exit pupil phase based on the pixel-level PD algorithm. The slit diffraction effect of the spliced ​​space telescope affects the grayscale value of some image pixels. Although the grayscale value is difficult to estimate, the specific pixel position can be determined based on the slit diffraction theory. Specifically, the slit size during on-orbit image acquisition can be obtained based on the distribution form and geometric size of the sub-mirrors of the spliced ​​space telescope. The slit diffraction light intensity distribution is calculated based on the slit diffraction theory and optical imaging theory, and then the distribution law of the slit diffraction fringes on the image plane is obtained. According to the distribution law of the slit diffraction fringes, the following is set. Figure 4 As shown in the pixel filtering template, the number of pixels of the pixel filtering template is consistent with the number of pixels of the collected image plane PSF image, that is, the same as the number of pixels of the in-focus PSF image and the out-of-focus PSF image, wherein the pixel value at the corresponding diffraction fringe position on the pixel filtering template is set to 0, and the pixel value at other positions is set to 1, and the pixel filtering template is also quantized by a two-dimensional matrix.

[0060] According to the intensity two-dimensional matrix of the original unfiltered in-focus PSF image and out-of-focus PSF image and , the intensity two-dimensional matrices of the in-focus PSF image and the out-of-focus PSF image are retrieved through the pixel screening template and expressed as and The specific implementation method is: the matrix corresponding to the pixel screening template is respectively and After multiplying the two matrices, the grayscale values ​​of the pixels in the focus PSF image and the defocus PSF image change as follows: the grayscale values ​​of the pixels with diffraction fringe intensity distribution are set to 0, and the grayscale values ​​of the remaining pixels remain unchanged, that is, non-diffraction pixels. For the specific processing effect of the above process, please refer to Figures 5 and 6 changes.

[0061] Based on the pixel-level PD algorithm, the system exit pupil phase is solved. First, the in-focus PSF image and the out-of-focus PSF image are used to establish the objective function according to Fourier optics theory. The solution of the objective function is the system exit pupil phase to be determined. Specifically, it can be expressed as:

[0062] ;

[0063] in, is the objective function The solution of is the exit pupil phase of the system to be solved, It represents the intensity two-dimensional matrix of any image point image after being filtered by the pixel filtering template, that is, and , represents the inverse Fourier transform, Represents the total number of selected image plane spot images, which is 2.

[0064] Objective Function The process of solving is essentially a numerical optimization process. Therefore, in the embodiment of the present invention, the L-BFGS algorithm is used for optimization, wherein the optimal estimated value of the system exit pupil phase is As the initial value of the objective function optimization algorithm, that is, the starting point of the L-BFGS algorithm optimization, the system exit pupil phase calculated by the PD algorithm is recorded as .

[0065] S4: To meet the wavefront detection accuracy requirements, it is necessary to cross-apply the GS algorithm described in S2 and the PD algorithm described in S3 to calculate the final system exit pupil phase through a loop iteration. For details, please refer to Figure 7 , the system exit pupil phase calculated by S3 As the initial random phase of the GS algorithm, re-execute S2 and solve the new optimal estimate of the system exit pupil phase again through the adjusted GS algorithm model ; Using the new system exit pupil phase best estimate Replace the initial value of the previous PD algorithm , and then start from a new starting point Re-execute S3 to calculate the new system exit pupil phase , continue the iteration calculation according to the above single iteration until the iteration result meets the iteration termination condition, then stop the iteration and calculate the final system exit pupil phase .

[0066] According to the wavefront detection accuracy, the iteration termination condition is set as:

[0067] ;

[0068] in, represents the number of iterations, Indicates The system exit pupil phase calculated by the iteration is Indicates -1 Iteration calculated system exit pupil phase, This is a constant set according to the wavefront detection accuracy and can be changed according to the accuracy requirements.

[0069] Assume If the iteration satisfies the above iteration termination conditions, then The system exit pupil phase calculated by the iteration This is the final system exit pupil phase .

[0070] The embodiment of the present invention can effectively eliminate the influence of slit diffraction on the wavefront detection accuracy of the spliced ​​space telescope through cross-iteration of the GS algorithm and the PD algorithm. The GS algorithm can quickly solve the system exit pupil phase through two Fourier transforms. The solution process depends on the grayscale values ​​of all pixels in the image plane PSF image. The phase solution speed is fast, but it cannot effectively eliminate abnormal pixels affected by the slit diffraction. The PD algorithm can effectively eliminate abnormal data points and construct an objective function, but the use of the PD algorithm alone can easily cause the objective function to fall into a local extreme value when searching for the optimal solution, and it is impossible to correctly calculate the system exit pupil phase. Therefore, the present invention cross-iterates the GS algorithm and the pixel-level PD algorithm to complement each other's advantages, which is conducive to finding the global optimal solution for the objective function of the pixel-level PD algorithm and improves the accuracy of the exit pupil phase solution.

[0071] As a preferred implementation, the above-mentioned method for eliminating the influence of slit diffraction on the wavefront detection accuracy of a space telescope can be applied to a spliced ​​space telescope system to improve the accuracy of wavefront detection. In other words, a spliced ​​space telescope system is designed, which uses the method disclosed in the present invention to eliminate the influence of slit diffraction on the wavefront detection accuracy of a space telescope to perform wavefront detection.

[0072] In short, the above description is only a preferred embodiment of this specification and is not intended to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included in the protection scope of this specification.

[0073] The systems, devices, modules or units described in one or more of the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer.

[0074] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0075] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A method for eliminating the influence of slit diffraction on wavefront detection, characterized in that: include: S1: Collect in-focus image spot images and out-of-focus image spot images; S2: Solve the exit pupil phases of the in-focus image spot image and the defocused image spot image respectively by using the GS algorithm, and design the optimal estimate of the system exit pupil phase in combination with the known defocus amount of the defocused image spot image. The optimal estimate of the system exit pupil phase The calculation formula is: ； in, is the defocus amount of the defocused image plane spot image, is the two-dimensional phase matrix of the exit pupil surface of the in-focus image spot image, is a two-dimensional phase matrix of the exit pupil plane phase of the defocused image plane spot image; S3: Construct the objective function of the system exit pupil phase solution based on the PD algorithm. for: ； in, is the objective function The solution of is the exit pupil phase of the system to be solved, It represents the intensity two-dimensional matrix of any image point image after being filtered by the pixel filtering template. represents the inverse Fourier transform, represents the system pupil, is an imaginary unit, represents the initial random phase, Indicates the total number of selected image plane spot images, which is 2; and using the best estimated value of the system exit pupil phase as an initial value for optimization, calculating the system exit pupil phase; S4: Iterate the calculation of S2 and S3. A single iteration is: The system exit pupil surface phase calculated by S3 is used as the initial random phase of the GS algorithm, and S2 is re-executed to calculate a new optimal estimated value of the system exit pupil surface phase; the new optimal estimated value of the system exit pupil surface phase is used as a new optimal initial value of the PD algorithm, and S3 is re-executed; After the iteration termination condition is met, the final system exit pupil phase is obtained; The iteration termination condition is: ； in, represents the number of iterations, Indicates The system exit pupil phase calculated by the iteration is: Indicates -1 Iteration calculated system exit pupil phase, is a constant set according to the wavefront detection accuracy.

2. The method for eliminating the influence of slit diffraction on wavefront detection as claimed in claim 1, characterized in that: In the S1, it also includes: filtering the in-focus image plane spot image and the out-of-focus image plane spot image through a Gaussian filter mask to correct the pixel grayscale value.

3. The method for eliminating the influence of slit diffraction on wavefront detection as claimed in claim 2, characterized in that: Get the intensity two-dimensional matrix of the in-focus image point image after filtering and the intensity two-dimensional matrix of the defocused image spot image after filtering ,Will and Substitute them into the phase recovery model based on the GS algorithm to solve the phase two-dimensional matrix of the exit pupil surface of the in-focus image plane spot image and the phase two-dimensional matrix of the exit pupil phase of the defocused image plane spot image .

4. The method for eliminating the influence of slit diffraction on wavefront detection as claimed in claim 3, characterized in that: Before constructing the objective function of the system exit pupil phase solution, it also includes: setting a pixel screening template according to the light intensity distribution law of the slit diffraction stripes of the space telescope, the pixel value at the slit diffraction stripe position is 0, and the pixel value at other positions is 1.

5. The method for eliminating the influence of slit diffraction on wavefront detection as claimed in claim 4, characterized in that: The intensity two-dimensional matrix of the in-focus image spot image after filtering is and the intensity two-dimensional matrix of the defocused image spot image after filtering The intensity two-dimensional matrix of the pixel screening template is multiplied respectively to obtain the intensity two-dimensional matrix of the in-focus image plane spot image after the pixel screening template is screened. The intensity two-dimensional matrix of the defocused image spot image after the pixel screening template is screened .

6. A spliced ​​telescope system, characterized in that: Wavefront detection is performed using the method for eliminating the influence of slit diffraction on wavefront detection as described in any one of claims 1 to 5.

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