A high-precision restoration method for large-field-of-view spliced ​​space telescope images

Abstract

The invention relates to the technical field of space telescope image processing, and specifically provides a method for high-precision restoration of large-field-of-view spliced ​​space telescope images, constructs the distribution relationship of wavefront aberrations of different frequencies with the field of view according to the optical parameters of the telescope, and based on the relationship between the intensity two-dimensional matrix of the PSF image of the image plane of any field of view and the wave aberration of the corresponding field of view in Fourier optical theory, measures the image plane PSF image of a specific field of view through a wavefront sensor arranged on the telescope, calculates the wave aberration of the specific field of view based on the measured image plane PSF image, and derives the PSF of any field of view through the distribution law of wavefront aberrations of different frequencies with the field of view and the relationship between the intensity two-dimensional matrix of the PSF image of the image plane and the wave aberration, and uses the PSF of any field of view derived from the measured PSF to realize high-precision restoration of the spliced ​​space telescope image through the image block restoration method. The invention uses the measured PSF for image restoration, solves the drawback of using the estimated PSF in the traditional non-blind deconvolution, and improves the restoration accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of space telescope image processing, and in particular provides a high-precision restoration method for a large-field-of-view spliced ​​space telescope image. Background Art

[0002] With the development of space technology, the performance of space telescopes has gradually become another high ground for countries to compete. Light-gathering ability and resolution are important indicators of telescope performance, and both are limited by the effective aperture of the primary mirror. The effective aperture of "integrated" space telescopes (such as Hubble) with a single mirror is difficult to further increase due to limitations such as reflector manufacturing, system integration, and whole-machine transportation and launch. The use of a "spliced" structure can effectively break through the above limitations and is one of the effective ways to develop large-aperture space telescopes.

[0003] Compared with the "integrated" space telescope, the "spliced" space telescope faces huge challenges in image quality correction. On the one hand, the mechanical positioning accuracy of the spliced ​​sub-mirror module on orbit is in the order of millimeters. In order to ensure that the "spliced" telescope has the same observation performance as the "integrated" telescope, the accuracy of the calculation of the misalignment of the spliced ​​sub-mirrors on orbit needs to reach the order of nanometers, and the cost of nanometer-level calculation and control on orbit is relatively high. On the other hand, the use of a spliced ​​primary mirror significantly increases the sensitivity of the system's image quality to spatial disturbances, posing a severe challenge to image quality maintenance. Environmental disturbance factors such as thermal and mechanical factors in orbit continue to exist, making it difficult to rely solely on mechanical structures to maintain nanometer-level precision between sub-mirrors for a long time.

[0004] The space image restoration technology using non-blind / blind deconvolution can effectively reduce the accuracy requirements of the "stitched" space telescope for on-orbit image quality correction and image quality maintenance based on hardware conditions through image post-processing. However, the space image restoration methods using non-blind / blind deconvolution are all centered on the high-precision estimation of the true PSF, but the estimated PSF has a pathological nature, and it is difficult to further improve the PSF estimation accuracy at the algorithm level, that is, the image restoration accuracy is difficult to further improve. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a high-precision restoration method for a large-field-of-view spliced ​​space telescope image. By obtaining the wave aberration of a specific field of view, based on the distribution law of different types of wave aberration coefficients with the field of view, the wave aberration of any field of view is deduced from the wave aberration of the specific field of view, and then the PSF of any field of view is obtained. The known PSF is used to replace the PSF obtained by estimation during non-blind deconvolution, thereby improving the on-orbit image restoration accuracy of the spliced ​​space telescope.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0007] The invention provides a high-precision restoration method for a large-field-of-view spliced ​​space telescope image, comprising:

[0008] S1: Construct the relationship between wave aberration and field of view distribution of different frequencies of the spliced ​​space telescope;

[0009] S2: Construct the relationship between the intensity two-dimensional matrix of the PSF image on the image plane of any field of view and the corresponding field of view wave aberration;

[0010] S3: collecting the image plane PSF image through a wavefront sensor device set at a specific field of view, and calculating the wave aberration of the specific field of view;

[0011] S4: The wave aberration of any field of view is obtained by calculating the wave aberration of a specific field of view, and the image plane PSF image intensity two-dimensional matrix of any field of view is constructed by the wave aberration of any field of view to achieve high-precision restoration of the spliced ​​space telescope image.

[0012] Preferably, in S1, according to the wavefront aberration characteristics of each spliced ​​sub-mirror of the spliced ​​space telescope, the subsystem-level wavefront aberration composed of all the spliced ​​sub-mirrors is expressed as follows using FringeZernike polynomials:

[0013] ;

[0014] in, Indicates that in a given field of view vector and pupil vector Subsystem-level wave aberrations under For the The pupil function of the spliced ​​sub-mirrors, For the The spliced ​​sub-mirrors, Fringe Zernike coefficients of the order terms, is the number of spliced ​​sub-mirrors, is the order of the Fringe Zernike polynomial, is the optical system structural parameter matrix, For the The pupil off-axis vector of the spliced ​​sub-mirrors, is the first Fringe Zernike polynomial The first spliced ​​sub-mirror order item;

[0015] The full-aperture wave aberration of all non-spliced ​​sub-mirrors is expressed using the Fringe Zernike polynomial as:

[0016] ;

[0017] in, Indicates that in a given field of view vector and pupil vector The full-aperture wave aberration of the non-spliced ​​sub-mirror under represents the Fringe Zernike coefficient of the non-spliced ​​sub-mirror;

[0018] The system wave aberration of the spliced ​​space telescope is calculated by the subsystem-level wave aberration and the full-aperture wave aberration of the non-spliced ​​sub-mirror:

[0019] ;

[0020] in, Indicates that in a given field of view vector and pupil vector The system wave aberration under .

[0021] Preferably, in S2, the relationship between the intensity two-dimensional matrix of the PSF image on the image plane of any field of view and the corresponding field of view wave aberration is:

[0022] ;

[0023] in, is the intensity two-dimensional matrix of the image plane PSF image, i is the imaginary unit, is the wavelength of incident light, is the image plane coordinate vector, represents the inverse Fourier transform, is the normalized pupil 2D matrix, is the noise term.

[0024] Preferably, the wavefront sensing device is a wavefront sensor.

[0025] Preferably, the in-focus PSF image and the out-of-focus PSF image are respectively collected by a wavefront sensor device, and the wave aberration of a specific field of view is calculated based on the phase difference principle.

[0026] Preferably, in S4, high-precision image restoration is performed by an image block restoration method, and the large-field-of-view image collected by the spliced ​​space telescope in orbit is divided into multiple sub-areas. The wave aberration of a specific field of view is used to deduce the wave aberration of the field of view corresponding to each sub-area, and the wave aberration of the field of view corresponding to each sub-area is used to construct a two-dimensional matrix of image plane PSF image intensity of the field of view corresponding to each sub-area, thereby realizing high-precision restoration of the spliced ​​space telescope image.

[0027] Compared with the prior art, the invention can achieve the following beneficial effects:

[0028] The present invention calculates the wave aberration of a specific field of view through the image plane PSF image measured by the wavefront sensor, and derives the wave aberration of any field of view based on the distribution law system of wave aberrations of different frequencies and the field of view from the measured wave aberration of the specific field of view, thereby obtaining the PSF of any field of view, and then improving the restoration accuracy of the large field of view image through the image block restoration method. The present invention solves the drawback that the PSF required for non-blind deconvolution of the spliced ​​space telescope image is all estimated, and the PSF obtained by the wavefront sensor is used to achieve large field of view image restoration, thereby improving the observation performance of the telescope. In the prior art, the PSF in the space telescope image restoration process is estimated by an algorithm, and it is difficult to overcome the pathological nature of the estimated PSF. The PSF obtained by the present invention through actual measurement and derivation is closer to the actual situation, and can effectively improve the restoration accuracy. It is of great significance to reduce the demand for image quality correction and image quality maintenance accuracy of the spliced ​​space telescope on-orbit relying on hardware conditions, improve the image restoration accuracy of the spliced ​​space telescope on-orbit, and improve the observation performance of the spliced ​​space telescope.

[0029] In addition, there are also existing methods for image restoration based on measured PSFs, but this method requires collecting PSFs of different fields of view on the main focal plane of the spliced ​​space telescope and using the measured multiple PSFs for image restoration. However, the restoration accuracy of this method depends on the number of PSFs of different fields of view collected. The more PSFs of different fields of view collected, the higher the restoration accuracy. The PSF collection process of this method is very cumbersome and the workload is extremely large. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0031] Figure 1 is a flow chart of a method for high-precision image restoration provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of image sub-region division provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0036] 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.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0038] See also Figure 1 In one embodiment of the present invention, a high-precision restoration method for a large-field-of-view spliced ​​space telescope image is provided, which mainly solves the problem of obtaining the PSF required for non-blind deconvolution of the spliced ​​space telescope image. Traditional methods estimate the PSF through an algorithm and use the estimated PSF to restore the spliced ​​space telescope image. However, the estimated PSF has a pathological property, and it is difficult to improve the PSF estimation accuracy at the algorithm level, so the accuracy of image restoration using the estimated PSF is low. Therefore, the present invention derives the PSF of any field of view through the measured PSF collected from a specific field of view. The derived PSF is closer to the real PSF, and the accuracy of image restoration using it is higher. Specifically, the processing process is as follows:

[0039] S1: First, the relationship between wave aberration and field of view distribution of different frequencies of the spliced ​​space telescope is constructed. Each spliced ​​sub-mirror of the spliced ​​space telescope and the subsequent optical group corresponding to each sub-mirror can be regarded as an independent off-axis system. Therefore, according to the number of spliced ​​sub-mirrors, optical parameters and wave aberration characteristics of the spliced ​​space telescope, the subsystem-level wave aberration composed of all spliced ​​sub-mirrors is expressed as:

[0040] ;

[0041] in, Indicates that in a given field of view vector and pupil vector Subsystem-level wave aberrations under , , , and is a natural number, representing the different order terms in the polynomial expansion, For the The wave aberration coefficient corresponding to the spliced ​​sub-mirrors is: For the The pupil vector of the spliced ​​sub-mirrors, For the The pupil off-axis vector of the spliced ​​sub-mirrors, is the number of spliced ​​sub-mirrors.

[0042] Furthermore, the subsystem-level wave aberration is characterized by the Fringe Zernike polynomials as:

[0043] ;

[0044] in, For the The pupil function of the spliced ​​sub-mirrors, For the The spliced ​​sub-mirrors, Fringe Zernike coefficients of the order terms, is the order of the Fringe Zernike polynomial, is the optical system structural parameter matrix, is the Fringe Zernike polynomial.

[0045] The Fringe Zernike polynomials can be used to effectively characterize the wavefront aberration of the exit pupil of a large-field-of-view spliced ​​space telescope system, directly reflect the relationship between the system structural parameters and the system wavefront aberration, and help to subsequently construct a quantitative analytical relationship between the wavefront aberration coefficients of different frequencies in the full frequency band and the field of view.

[0046] Similarly, for the non-spliced ​​sub-mirrors in the spliced ​​space telescope, such as the secondary mirror, they are also divided and represented in the form of spliced ​​sub-mirrors, and the full-aperture wave aberration of all non-spliced ​​sub-mirrors is expressed using the Fringe Zernike polynomial as follows:

[0047] ;

[0048] in, Indicates that in a given field of view vector and pupil vector The full-aperture wave aberration of the non-spliced ​​sub-mirror under Represents the Fringe Zernike coefficient of the non-spliced ​​sub-mirror.

[0049] Furthermore, the system wave aberration of the spliced ​​space telescope is obtained by integrating the subsystem-level wave aberration and the full-aperture wave aberration of the non-spliced ​​sub-mirrors:

[0050] ;

[0051] in, Indicates that in a given field of view vector and pupil vector The system wave aberration under .

[0052] Based on the above-mentioned systematic wave aberration, a quantitative analytical relationship between the wave aberration coefficients of different frequencies and the field of view in the full frequency band of the spliced ​​space telescope can be constructed, that is, the distribution relationship of wavefront aberrations of different frequencies with the field of view is described. Furthermore, the wave aberration of any field of view can be derived from the wave aberration of a specific field of view.

[0053] S2: The relationship between the intensity two-dimensional matrix of the PSF image on the image plane of any field of view and the corresponding field of view wave aberration is derived to construct a PSF model of a spliced ​​space telescope with any field of view and a wide spectrum. Specifically, based on the Fourier optical theory, a quantitative relationship between the intensity two-dimensional matrix of the PSF image on the image plane of the wide spectrum at any field of view position and the corresponding field of view wave aberration is constructed. The specific relationship is:

[0054] ;

[0055] in, is the intensity two-dimensional matrix of the image plane PSF image, is the image plane coordinate vector, represents the inverse Fourier transform, is the normalized pupil two-dimensional matrix, which is specifically given 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 exponential function with the natural constant e as base, is the contribution of the slit diffraction effect to the two-dimensional matrix data of the PSF image on the image plane, which is a noise term, and i is an imaginary unit.

[0056] As a preferred embodiment, based on the above formula, a quantitative relationship between the two-dimensional matrix distribution of the image PSF image intensity at any field of view position and the wave aberration is constructed. At the same time, considering the wavelength factor, the above formula is further expressed as:

[0057] ;

[0058] in, is the wavelength of incident light, It is still the two-dimensional matrix of the intensity of the image plane PSF image, indicating the introduction of the wavelength factor. It is still the normalized pupil two-dimensional matrix, which means the wavelength factor is introduced. is the noise term. To overcome the influence of the slit diffraction effect, it is usually necessary to suppress the inherent slit diffraction of the spliced ​​space telescope through filtering, so can represent the noise term after filtering, but the slit diffraction effect cannot be completely eliminated after filtering. Therefore, There is still a contribution value of slit diffraction to the two-dimensional moment data distribution of image intensity. The specific filtering process and whether filtering is performed do not belong to the protection content of the present invention and will not be described in detail again.

[0059] As a preferred embodiment, based on the above formula, the quantitative parameters of the detector on the spliced ​​space telescope can be further considered, and the above formula can be further corrected to:

[0060] ;

[0061] in, represents the detector parameters, It is the noise term after superimposing the contribution value of detector noise to the two-dimensional matrix data distribution of the image plane PSF image intensity, which is related to the wavelength, field of view and detector parameters.

[0062] In summary, the on-orbit PSF model of arbitrary field-of-view wide spectrum has been completed, that is, the relationship between the intensity two-dimensional matrix of the PSF image on the image plane of arbitrary field of view and the corresponding field-of-view wave aberration has been constructed. Therefore, the wave aberration of the field of view can be used to describe the PSF image intensity on the image plane of the corresponding field of view.

[0063] S3: A large-field-of-view spliced ​​space telescope usually has a wavefront sensor set at a specific field-of-view position. The spliced ​​space telescope is pointed at a specific celestial body area in orbit, and the wavefront sensor can collect and obtain the image plane PSF image of the specific field of view, that is, the star spot image of the specific field of view. In order to obtain the wave aberration of the specific field of view, in an embodiment of the present invention, the wave aberration of the specific field of view is calculated based on the phase difference principle. Therefore, it is necessary to collect two PSF images, namely, the in-focus PSF image and the out-of-focus PSF image, respectively through the wavefront sensor on the spliced ​​space telescope, and solve the wave aberration of the specific field of view through the phase difference of the two PSF images. Specifically, the objective function for solving the wave aberration of the specific field of view is constructed based on the phase difference of the two PSF images:

[0064] ;

[0065] in, is the objective function The solution of the specific field of view wave aberration to be solved , Represents different PSF images of the image plane collected by the wavefront sensor, namely the in-focus PSF image and the out-of-focus PSF image.

[0066] The process of solving the wave aberration of a specific field of view through the above objective function is essentially a process of numerical optimization. The high-precision solution of the wave aberration of a specific field of view can be achieved through the pixel-level L-BFGS algorithm.

[0067] S4: Construct a large field of view image restoration model. Specifically, the wave aberration of a specific field of view obtained in S3 is converted into Substituting the relationship between wave aberration and field of view distribution of different frequencies of the spliced ​​space telescope, the wave aberration of any field of view can be calculated from the quantitative analytical relationship between the wave aberration coefficient of different frequencies in the full field of view and the field of view. The arbitrary field of view is recorded as , the wave aberration of any field of view is recorded as Then, the intensity two-dimensional matrix of the PSF image on the image plane of any field of view is reconstructed according to the relationship between the intensity two-dimensional matrix of the PSF image on the image plane of any field of view and the corresponding wave aberration of the field of view, and the intensity two-dimensional matrix of the PSF image on the image plane of any field of view is obtained. for:

[0068] ;

[0069] in, For the The quantitative analytical relationship between the wave aberration coefficient distribution in the whole field of view and the field of view reflects the wave aberration of each spliced ​​sub-mirror corresponding to the field of view. For a specific field of view The contribution of the detector noise to the two-dimensional matrix data distribution of the PSF image intensity on the image plane and the contribution of the slit diffraction to the two-dimensional moment data distribution of the image intensity are superimposed.

[0070] The image plane PSF image intensity two-dimensional matrix of any field of view In the frequency domain it can be expressed as:

[0071] ;

[0072] in, is the frequency domain representation of the two-dimensional matrix of the image plane PSF image intensity, is the frequency domain representation of the ideal PSF of the spliced ​​space telescope optical system, that is, the frequency domain representation of the two-dimensional matrix of the image plane PSF image intensity without noise interference. is the frequency domain representation of the noise term, which mainly includes slit diffraction and detector noise.

[0073] After obtaining the two-dimensional matrix of the PSF image intensity of the image plane of any field of view, the image restoration can be performed according to the existing non-blind / blind deconvolution spatial image restoration method. Specifically, the image quality degradation process of the spliced ​​space telescope is expressed as:

[0074] ;

[0075] in, For the degraded image, is the “real” image, which means the original image or the target image, which is the image that the telescope should ideally observe before any degradation process occurs. is random noise, is the spatial representation of the system degradation function, is the convolution symbol.

[0076] The degradation process is expressed in the frequency domain as:

[0077] ;

[0078] in, is the frequency domain representation of the degraded image, is the imaging system transfer function, which is related to the PSF of the spliced ​​space telescope optical system. When the error is not considered, That is same, is the frequency domain representation of the actual acquired image, is the frequency domain representation of random noise.

[0079] The embodiment of the present invention uses the wavefront sensor to collect the wave aberration of a specific field of view, and derives the image plane PSF image intensity two-dimensional matrix of any field of view that is closer to the real PSF of the system through measured data, which solves the dependence on the estimated PSF when restoring the image through image deconvolution. In order to further improve the restoration accuracy of the image collected by the spliced ​​space telescope, the large field of view image collected by the spliced ​​space telescope in orbit can be restored by the image block restoration method. Please refer to Figure 2 , first divide the large field of view image into sub-regions, each sub-region can be restored separately, and the field of view coordinates of the center point of each sub-region are expressed as , the number of sub-regions divided depends on the restoration accuracy. The number of divisions directly affects the restoration accuracy. More sub-regions means higher local adaptability and can bring higher restoration accuracy. When further subdividing the sub-regions no longer significantly improves the accuracy of the restored image, the current number of sub-region divisions can be considered as the optimal sub-region division value. Therefore, the frequency sub-region image restoration model constructed by the image block restoration method is:

[0080] ;

[0081] Furthermore, the wave aberration of a specific field of view is used to deduce the wave aberration of the field of view corresponding to each sub-region, and the wave aberration of the field of view corresponding to each sub-region is used to construct a two-dimensional matrix of image plane PSF image intensity of each sub-region corresponding to the field of view, so as to restore the image of each sub-region. After the restoration of all sub-region images is completed, a high-precision restored image of the large field of view image collected by the spliced ​​space telescope in orbit can be obtained.

[0082] 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.

[0083] The systems, devices, modules or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0084] 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.

[0085] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0086] 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 high-precision restoration method for large-field-of-view spliced ​​space telescope images, characterized in that: include: S1: Construct the relationship between wave aberration and field of view distribution of different frequencies of the spliced ​​space telescope; according to the wave aberration characteristics of each spliced ​​sub-mirror of the spliced ​​space telescope, the subsystem-level wave aberration composed of all spliced ​​sub-mirrors is expressed by Fringe Zernike polynomials as follows: ； in, Indicates that in a given field of view vector and pupil vector Subsystem-level wave aberrations under For the The pupil function of the spliced ​​sub-mirrors, For the The spliced ​​sub-mirrors, FringeZernike coefficients of the order terms, is the number of spliced ​​sub-mirrors, is the order of the Fringe Zernike polynomial, is the optical system structural parameter matrix, For the The pupil off-axis vector of the spliced ​​sub-mirrors, is the FringeZernike polynomial; The full-aperture wave aberration of all non-spliced ​​sub-mirrors is expressed using the Fringe Zernike polynomial as: ； in, Indicates that in a given field of view vector and pupil vector The full-aperture wave aberration of the non-spliced ​​sub-mirrors under represents the FringeZernike coefficient of the non-spliced ​​sub-mirror; The system wave aberration of the spliced ​​space telescope is calculated by the subsystem-level wave aberration and the full-aperture wave aberration of the non-spliced ​​sub-mirror: ； in, Indicates that in a given field of view vector and pupil vector System wave aberration under ; S2: Construct the relationship between the intensity two-dimensional matrix of the PSF image on the image plane of any field of view and the corresponding field of view wave aberration; the relationship between the intensity two-dimensional matrix of the PSF image on the image plane of any field of view and the corresponding field of view wave aberration is: ； in, is the intensity two-dimensional matrix of the image plane PSF image, i is the imaginary unit, is the wavelength of incident light, is the image plane coordinate vector, represents the inverse Fourier transform, is the normalized pupil 2D matrix, is the noise term; S3: collecting an image plane PSF image by a wavefront sensor device arranged at a specific field of view, and calculating the wavefront aberration of the specific field of view; S4: Substitute the wave aberration of the specific field of view obtained in S3 into the relationship between the wave aberration of different frequencies and the field of view distribution of the spliced ​​space telescope, calculate the wave aberration of any field of view through the wave aberration of the specific field of view, and construct a two-dimensional matrix of the image plane PSF image intensity of any field of view from the wave aberration of any field of view, so as to achieve high-precision restoration of the spliced ​​space telescope image.

2. The high-precision restoration method for large-field-of-view spliced ​​space telescope images according to claim 1, characterized in that: The wavefront sensing device is a wavefront sensor.

3. The high-precision restoration method for large-field-of-view spliced ​​space telescope images according to claim 2, characterized in that: The in-focus PSF image and the out-of-focus PSF image are respectively collected by the wavefront sensor device, and the wave aberration of the specific field of view is calculated based on the phase difference principle.

4. The high-precision restoration method for large-field-of-view spliced ​​space telescope images according to claim 1, characterized in that: In S4, high-precision image restoration is performed by an image block restoration method, and the large-field-of-view image collected by the spliced ​​space telescope on orbit is divided into multiple sub-areas. The wave aberration of the specific field of view is used to deduce the wave aberration of the field of view corresponding to each sub-area, and the wave aberration of the field of view corresponding to each sub-area is used to construct a two-dimensional matrix of image plane PSF image intensity of the field of view corresponding to each sub-area, thereby realizing high-precision restoration of the spliced ​​space telescope image.

Images