Method and device for calibrating optical sensitivity of flutter imaging model of space camera

Abstract

The invention provides a space camera flutter imaging model optical sensitivity calibration method and device, and the method comprises the steps: recognizing the plane linear movement distance of a first optical part with the maximum surface type change degree and the rotation angles of three axes based on the design of a space camera; the influence of the movement and rotation of the optical element on the imaging quality is evaluated by determining an optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle, and the behaviors of the optical element under different conditions are obtained, so that the stability of a space camera system is improved by taking corresponding measures. The determined target image motion value is input into the optical sensitivity equation to obtain correction coefficients of the plane linear movement distance and the rotation angles of the three axes, and the correction coefficients are used for calibrating the optical sensitivity and correcting imaging errors caused by flutter of the space camera, so that the imaging quality of the space camera is improved, and the imaging accuracy of the space camera is improved. And the stability of the space camera in a complex environment can be enhanced.

Description

Technical Field

[0001] The present application relates to the field of space remote sensing imaging simulation technology, and in particular to a method and device for calibrating the optical sensitivity of a space camera flutter imaging model. Background Art

[0002] High-frequency perturbations of the platform's moving components can cause minute relative motion and deformation of optical components such as the primary, secondary, and tertiary mirrors, as well as the focal plane. This effect manifests primarily as line-of-sight (LOS) wobble, impacting key performance indicators such as the pointing accuracy, stability, and resolution of high-precision spacecraft payloads. This, in turn, can affect the imaging performance of high-precision satellites, resulting in image radiometric and geometric quality issues. Because the electromechanical components of the perturbation source cannot be disassembled, it is difficult to arrange measurement points for modal identification. Furthermore, the modal characteristics of the perturbation source change after satellite installation, making ground-based perturbation force (torque) test results infeasible.

[0003] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the first purpose of this application is to propose a calibration method for the optical sensitivity of a space camera flutter imaging model. The optical sensitivity equation and the target image shift value of the sequence image are used to determine the correction coefficients of the plane linear movement distance and the rotation angle of the three axes, thereby completing the calibration of the optical sensitivity of the space camera flutter imaging model.

[0006] The second objective of this application is to provide a device for calibrating the optical sensitivity of a space camera flutter imaging model.

[0007] The third objective of this application is to provide an electronic device.

[0008] The fourth object of this application is to provide a computer-readable storage medium.

[0009] A fifth object of this application is to provide a computer program product.

[0010] To achieve the above objectives, the first embodiment of the present application proposes a method for calibrating the optical sensitivity of a space camera flutter imaging model, comprising:

[0011] Obtaining a planar linear movement distance and three-axis rotation angles of a first optical component in three-dimensional space within a time domain sampling interval, wherein the first optical component is related to an optical component with the largest degree of surface shape change in the space camera;

[0012] Determine an optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle;

[0013] determining a target image shift value of a sequence of images according to a sequence of images of the space camera in the time domain sampling interval;

[0014] The target image shift value is input into the optical sensitivity equation to obtain correction coefficients of the plane linear movement distance and the rotation angles of the three axes, wherein the correction coefficients are used to calibrate the optical sensitivity of the space camera flutter imaging model.

[0015] To achieve the above-mentioned objectives, a second embodiment of the present application provides a device for calibrating the optical sensitivity of a space camera flutter imaging model, comprising:

[0016] A first acquisition module, configured to acquire a planar linear movement distance and three-axis rotation angles of a first optical component in three-dimensional space within a time domain sampling interval, wherein the first optical component is related to an optical component with the greatest degree of surface shape change in the space camera;

[0017] a second acquisition module, the second acquisition module being used to determine an optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle;

[0018] a third acquisition module, configured to determine a target image shift value of a sequence of images according to a sequence of images of the space camera in the time domain sampling interval;

[0019] A calibration module is configured to input the target image shift value into the optical sensitivity equation to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes, and calibrate the optical sensitivity of the space camera flutter imaging model based on the correction coefficients.

[0020] To achieve the above-mentioned objectives, the third embodiment of the present application proposes an electronic device, comprising: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement the optical sensitivity calibration method of the space camera vibration imaging model proposed in the first embodiment of the present application.

[0021] To achieve the above-mentioned purpose, the fourth aspect embodiment of the present application proposes a non-temporary computer-readable storage medium, which, when the instructions in the storage medium are executed by the processor of an electronic device, enables the electronic device to execute the method proposed in the first aspect embodiment of the present application.

[0022] To achieve the above-mentioned purpose, the fifth aspect embodiment of the present application proposes a computer program product, including a computer program, which implements the method proposed in the first aspect embodiment of the present application when executed by a processor in a communication device.

[0023] The present application provides a method and device for calibrating the optical sensitivity of a space camera's flutter imaging model. Based on the design of the space camera, the optical component with the largest surface shape change is identified as the first optical component, and the plane linear movement distance and the rotation angle of the three axes of the first optical component are measured within the time domain sampling interval, which helps to evaluate the dynamic performance of the optical component and its stability when subjected to external interference (such as vibration, temperature change, etc.); by determining the optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle, the impact of the movement and rotation of the optical component on the imaging quality can be effectively evaluated, and the behavior of the optical component under different conditions can be more accurately understood, so that corresponding measures can be taken to improve the stability of the space camera system; by inputting the determined target image shift value into the optical sensitivity equation, correction coefficients for the plane linear movement distance and the rotation angle of the three axes are obtained. These correction coefficients are used to calibrate the optical sensitivity and correct the imaging error caused by the flutter of the space camera, thereby improving the imaging quality of the space camera and helping to enhance the stability of the space camera in complex environments.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0026] Figure 1 A schematic flow chart of a method for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application;

[0027] Figure 2 A schematic flow chart of another method for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application;

[0028] Figure 3 A schematic flow chart of another method for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of the structure of a device for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application;

[0030] Figure 5 The figure is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0031] Exemplary embodiments are described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numbers in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible implementations consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0032] The terms used in the embodiments of this application are for the purpose of describing specific embodiments only and are not intended to limit the embodiments of this application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0033] It should be understood that although the terms first, second, third, etc. may be used to describe various information in the embodiments of the present application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the embodiments of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein may be interpreted as "at the time of" or "when" or "in response to a determination."

[0034] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0035] When operating in space, space cameras are subject to high-frequency disturbances generated by the platform's moving components (such as drive mechanisms and reaction wheels). These disturbances can cause minute relative motions and deformations in the camera's optical components, including the primary, secondary, and tertiary mirrors and focal plane, manifesting as line of sight (LOS) wobble. This wobble significantly impacts key performance indicators of high-precision spacecraft, such as payload pointing accuracy, stability, and resolution. Specifically, LOS wobble prevents the camera from accurately pointing at its target, impacting the accuracy of observation missions; persistent, minute wobble disrupts the camera's stability and reduces image quality; and LOS wobble blurs the image, reducing the camera's resolution and thus affecting the recognition and analysis of the observed object.

[0036] Furthermore, these effects can degrade the imaging performance of high-precision satellites, causing image radiometric and geometric quality issues such as blurring, distortion, and reduced contrast. Because the electromechanical components of the disturbance source are typically non-detachable, it is difficult to arrange measurement points for modal identification. Furthermore, the modal characteristics of the disturbance source change after installation, and ground-based disturbance force (torque) test results cannot be directly applied to the space environment, increasing the difficulty of accurately modeling and simulating the disturbance source.

[0037] To address the above challenges, the current approach is to simulate and analyze micro-vibration characteristics mainly through the identification and modeling of the dynamic characteristics of the disturbance source. This includes analyzing the coupling effect between the excitation source and the satellite structure and the optics of the space camera through frequency response, in order to understand the specific impact of the disturbance on the camera performance. However, due to the complex structure of the spacecraft, the initial finite element model has large errors. Therefore, the model needs to be corrected to improve the simulation accuracy. The objects of correction usually include design parameters such as size, density, elastic modulus, and shear modulus. The purpose of the correction is to make the eigenvalues and eigenvectors obtained from the finite element model close to the true experimental values, such as the static displacement, dynamic response, and frequency response function, which are consistent with the experimental results. For the optical-mechanical integration analysis of space cameras, the most important model correction indicator is the simulation accuracy of the line of sight image shift, which can then achieve an estimation of the image quality.

[0038] The following describes a method and apparatus for calibrating the optical sensitivity of a space camera flutter imaging model according to an embodiment of the present application with reference to the accompanying drawings.

[0039] Figure 1 A schematic flow chart of a method for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application.

[0040] like Figure 1 As shown, the calibration method includes but is not limited to the following steps:

[0041] S101, obtaining a planar linear movement distance and three-axis rotation angles of a first optical component in a three-dimensional space within a time domain sampling interval, wherein the first optical component is related to an optical component with the greatest degree of surface shape change in a space camera.

[0042] In one feasible implementation, a three-dimensional model of the space camera system can be determined based on the design documentation or actual assembly of the space camera. Finite element analysis or thermal analysis is then performed on the three-dimensional model to simulate the temperature changes in the space camera's operating environment and analyze the effects of temperature changes on the optical component materials, including thermal expansion and contraction, thermal stress, and so on. The changes in the optical component mirror shape caused by these thermal effects are then calculated. Considering the mechanical effects on the optical components of the space camera during operation, such as gravity, vibration, and impact, structural analysis or finite element analysis can be used to simulate the effects of these mechanical effects on the optical components. The changes in the mirror shape caused by the mechanical effects are then calculated. The calculation results of the thermal and mechanical effects are combined to obtain a comprehensive surface shape change.

[0043] In one feasible embodiment, based on the obtained comprehensive surface profile change, the first optical element with the greatest surface profile change in the space camera is determined. During a time-domain sampling interval, the position change of the first optical element in three-dimensional space can be continuously measured using a laser rangefinder or a high-precision displacement sensor, and the position data of each sampling point, including the coordinates in the X, Y, and Z directions, can be recorded. The linear movement distance of the first optical element within the plane can then be calculated by calculating the position difference between adjacent sampling points. The rotation angle of the first optical element about the X, Y, and Z axes can be measured using a gyroscope, a photoelectric encoder, or an angle sensor, and the rotation angle data for each sampling point can be continuously recorded during the time-domain sampling interval.

[0044] In one feasible implementation, vector operations or geometric methods can be used to verify the linear movement distance, and data fitting or interpolation methods can be used to verify the rotation angles of the three axes to ensure the accuracy of the results. The linear movement distance and rotation angle data are then comprehensively analyzed to understand the motion patterns and characteristics of the first optical element within the time domain sampling interval. Based on the analysis results, the performance and stability of the space camera can be evaluated and optimized.

[0045] S102, determining an optical sensitivity equation corresponding to a plane linear movement distance and a rotation angle.

[0046] In a feasible embodiment, optical sensitivity generally refers to the degree of response of an optical system to changes in light signals, which may be affected by a variety of factors, including the movement and rotation of optical components. The optical sensitivity equation depends on the specific optical system (in this embodiment, the optical system refers to a space camera system), the light source, the detector, and the movement and rotation mode of the space camera. In a space camera system, the five parameters of the position and posture of the optical component can be described by the degrees of freedom of the optical component. The five parameters may include: a first linear movement distance along the X-axis, a second linear movement distance along the Y-axis, a first rotation angle around the X-axis, a second rotation angle around the Y-axis, and a third rotation angle around the Z-axis, wherein the first linear movement distance and the second linear movement distance are summarized as plane linear movement distances in three-dimensional space; the first rotation angle, the second rotation angle, and the third rotation angle are summarized as rotation angles of three axes.

[0047] In a feasible embodiment, the five degrees of freedom of the first optical element and the corresponding optical axis image shift value at each sampling point are recorded within the time domain sampling interval. The collected data is preprocessed, including data cleaning, data normalization or data standard conversion. According to the characteristics of the data, a suitable regression model can be selected. In this embodiment, since five independent variables (five degrees of freedom) and one dependent variable (optical axis image shift) are involved, a multivariate regression model can be used. The preprocessed data is input into the selected regression model for training. During the training process, the regression model will try to find the best fit relationship between the independent variables and the dependent variables. After the training is completed, the optical sensitivity equation is extracted from the regression model, which describes the mathematical relationship between the five degrees of freedom and the optical image shift.

[0048] In a feasible implementation, the optical sensitivity equation can also be verified using data that has not participated in the training to ensure its accuracy and generalization ability, and then the optical sensitivity equation can be adjusted and optimized as necessary based on the verification results.

[0049] S103 , determining a target image shift value of a sequence of images according to a sequence of images of the space camera in a time domain sampling interval.

[0050] In one feasible embodiment, a spatial camera can be used to capture a series of images within a temporal sampling interval to form a sequence of images. The captured sequence of images is then preprocessed, including denoising and contrast enhancement, to improve image quality. The dynamic image motion signal of the spatial camera is then extracted from the preprocessed sequence of images. This process includes operations such as image registration and feature point matching. Based on the extracted dynamic image motion signal, the image motion at each sampling point or sampling interval is calculated. This can be achieved by comparing the positional changes of feature points in adjacent images. The image motion values of all sampling points or sampling intervals are then combined to determine a target image motion value for the sequence of images. This process includes: determining the direction and magnitude of the image motion from the captured sequence of images; converting the image motion values from two-dimensional coordinates to easily analyzable coordinates such as polar coordinates or rectangular coordinates; calculating the target image motion value using statistical methods (such as mean, median, mode, etc.), or obtaining the target image motion value by weighting the image motion values; and verifying the target image motion value using optical flow or temporal difference methods. If a significant difference is found, correction or recalculation is required.

[0051] S104 , inputting the target image shift value into an optical sensitivity equation to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes, wherein the correction coefficients are used to calibrate the optical sensitivity of the space camera flutter imaging model.

[0052] In one feasible implementation, the target image shift value includes a pixel-level planar linear motion distance and a rotation angle. The pixel-level target image shift value is then converted into a physical quantity comprising a three-dimensional planar linear motion distance parameter and a rotation angle parameter. The target image shift value (already converted into a physical quantity) is then input into an optical sensitivity equation, which is then solved using mathematical methods (such as matrix operations, numerical solutions, and multiple regression analysis) to obtain correction coefficients for the planar linear motion distance and the three-axis rotation angles.

[0053] In one feasible implementation, applying a correction factor can compensate for the effect of camera motion on image quality, thereby improving imaging quality. The correction factor can be used to optimize the camera flutter imaging model, more accurately describing the camera's motion characteristics and imaging performance.

[0054] In a feasible implementation, during the design phase of a space camera, the correction coefficient can be used as a guiding parameter to help optimize the mechanical structure and optical system of the space camera to reduce the impact of vibration on imaging quality.

[0055] In summary, the calibration method for the optical sensitivity of the space camera flutter imaging model provided in the embodiment of the present application, based on the design of the space camera, identifies the optical component with the largest surface shape change as the first optical component, and measures the plane linear movement distance and the rotation angle of the three axes of the first optical component within the time domain sampling interval, which helps to evaluate the dynamic performance of the optical component and the stability performance when subjected to external interference (such as vibration, temperature change, etc.); by determining the optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle, the impact of the movement and rotation of the optical component on the imaging quality can be effectively evaluated, and the behavior of the optical component under different conditions can be more accurately understood, so as to take corresponding measures to improve the stability of the space camera system; by inputting the determined target image shift value into the optical sensitivity equation, the correction coefficients of the plane linear movement distance and the rotation angle of the three axes are obtained. These correction coefficients are used to calibrate the optical sensitivity and correct the imaging error caused by the flutter of the space camera, thereby improving the imaging quality of the space camera and helping to enhance the stability of the space camera in complex environments.

[0056] Figure 2 A flowchart of another method for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application.

[0057] like Figure 2 As shown, the calibration method includes but is not limited to the following steps:

[0058] S201, obtaining a structural finite element model of a space camera.

[0059] In some embodiments, the space camera is a complex integrated optomechanical, electrical and thermal system, whose key components include: objective lens, that is, optical system and mechanism, such as lens, reflector, filter, etc.; detection, reception and circuit system, used for photoelectric conversion, signal amplification, processing, etc., composed of photoelectric detectors and circuits; thermal control device, used to control the temperature of the space camera, including thermal control coating, radiator, etc.; control and information processor, responsible for image data acquisition, storage, processing, etc.

[0060] In some embodiments, before obtaining the structural finite element model of the space camera, an accurate three-dimensional model is first required as a basis to depict the various components of the camera and their interconnections. Since finite element analysis consumes a large amount of computing resources, when converting the three-dimensional model into a structural finite element model, it is usually necessary to simplify some parts that do not affect the structural performance, such as fillets, small holes, and small plug-ins on the circuit board. The simplified model needs to be meshed. The size and shape of the mesh will directly affect the accuracy and computational efficiency of the analysis results. Generally, for parts with more regular structures, solid units based on regular hexahedrons can be used for modeling; for complex or irregular parts, a more flexible meshing method is required. In the finite element model, the correct materials and properties, such as density, elastic modulus, etc., can be assigned to each component. These parameters will directly affect the accuracy of the analysis results.

[0061] In some embodiments, the correct boundary conditions and loads can be applied to the structural finite element model to simulate the forces acting on the space camera during actual operation. For example, certain degrees of freedom of the box bottom plate can be fully constrained, and inertial loads can be applied along specific directions.

[0062] S202: Determine the planar linear movement distance and the rotation angles of the three axes of the first optical component in three-dimensional space according to the structural finite element model.

[0063] In some embodiments, the three-dimensional displacement of each optical component in the space camera based on the time domain sampling interval can be obtained according to the structural finite element model. As an example, the dynamic loads that may be applied to the space camera, such as vibration, temperature change, impact force, etc., can be defined according to the actual working environment of the space camera; the sampling frequency is determined according to the time domain sampling interval to ensure that all important dynamic responses can be captured. Appropriate boundary conditions are applied to the structural finite element model. These boundary conditions can limit the degrees of freedom of the optical component (including the first linear movement distance along the X-axis, the second linear movement distance along the Y-axis, the first rotation angle around the X-axis, the second rotation angle around the Y-axis, and the third rotation angle around the Z-axis) to simulate the constraints under actual conditions. The dynamic response analysis of each optical component in the space camera is then run using finite element analysis. After the analysis is completed, the three-dimensional displacement of each optical component in the time domain sampling interval is extracted.

[0064] In some embodiments, surface transformation data corresponding to the optical component can be determined based on each three-dimensional displacement. For example, finite element analysis or interferometry analysis can be performed on each three-dimensional data to obtain the surface transformation data corresponding to the optical component. The surface transformation data can be characterized based on the root mean square value and peak-to-peak value of the surface deformation of the optical component.

[0065] In some embodiments, the first optical element with the largest degree of surface shape change is obtained from all surface shape transformation data, and the plane linear movement distance and the rotation angles of the three axes of the first optical element in three-dimensional space are determined, wherein the plane linear movement distance includes a first linear movement distance along the X-axis direction and a second linear movement distance along the Y-axis direction; the rotation angle includes a first rotation angle around the X-axis, a second rotation angle around the Y-axis, and a third rotation angle around the Z-axis.

[0066] For further details on the plane linear movement distance and the rotation angles of the three axes in step S202, please refer to the relevant contents in the above embodiment, which will not be repeated here.

[0067] S203, determining an optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle.

[0068] In some embodiments, wavefront aberration data for each optical component in the space camera can be obtained based on the corresponding surface transformation data of the optical component. Each wavefront aberration data is then fitted using a least squares algorithm to obtain the corresponding Zernike polynomial coefficients. Ray tracing is performed on the structural data of the space camera and the Zernike polynomial coefficients to obtain the initial image shift value of the optical axis on the focal plane. A time domain transformation curve of the plane linear movement distance and rotation angle within the time domain sampling interval is obtained. Multiple regression analysis is then performed on the initial image shift value and the time domain transformation curve to obtain the optical sensitivity equation.

[0069] In some embodiments, the optical sensitivity equation is determined using the following formula:

[0070] aBDX+bBDY+cBTX+dBTY+eBTZ+f=ΔMT

[0071] Among them, BDX is the first linear movement distance along the X-axis; BDY is the second linear movement distance along the Y-axis; BTX is the first rotation angle around the X-axis; BTY is the second rotation angle around the Y-axis; BTZ is the third rotation angle around the Z-axis; a, b, c, d, and e are the five degrees of freedom coefficients of the first optical element; f is the linear correction parameter (an adjustment parameter introduced on the basis of maintaining the basic linear characteristics of the system or model to improve performance, increase accuracy or adapt to specific conditions, used to fine-tune the linear response of the system to meet specific application requirements); ΔMT is the image shift value (the image shift value includes the initial image shift value and the target image shift value).

[0072] For further details on step S203, please refer to the relevant contents in the above embodiment, which will not be repeated here.

[0073] S204 , determining a target image shift value of a sequence of images according to a sequence of images of the space camera in a time domain sampling interval.

[0074] In some embodiments, a sequence of images based on a temporal sampling interval is acquired by a space camera. For example, a space camera mounted on a flutter table can be used to image a target based on a temporal sampling interval (the temporal sampling interval includes multiple sampling intervals Δt, where the sampling interval Δt is set as an imaging integration time) to acquire the sequence of images.

[0075] In some embodiments, a reference frame and at least one search frame are determined from a set of sequential images, and a reference region corresponding to the reference frame and a search region corresponding to the search frame are determined. As an example, the reference frame uses the image center as a reference point, and extracts an M×M region from the image as the reference region, where M is less than half the short side of the image, and a lower limit of M is determined based on accuracy requirements and computing power requirements. The search frame uses the image center as a reference point, and extracts an (M+S)×(M+S) region from the image as the search region, where S is less than half the short side of the image.

[0076] In some embodiments, the first row projection vector and the first column projection vector corresponding to the reference area, as well as the second row projection vector and the second column projection vector corresponding to the search area are obtained. As an example, the first row projection vector and the first column projection vector corresponding to the reference area can be determined using the following formula:

[0077]

[0078] Among them, r REF is the row position of the reference area; c REF is the column position of the reference area; I ref (r REF ,c REF ) is the reference area (r REF ,c REF ) pixel grayscale value; M is the side length of the reference area; V REF (r REF ) is the reference area r REF Projection of the row; H REF (c REF ) is the reference area c REF Projection of column; V REF is the first row projection vector; H REF is the first column projection vector.

[0079] Furthermore, the second row projection vector and the second column projection vector corresponding to the search area can be expressed as:

[0080]

[0081] Among them, V ser is the second row projection vector; H ser is the second column projection vector.

[0082] In some embodiments, the target image motion value is determined based on the first row projection vector, the first column projection vector, each second row projection vector, and each second column projection vector. As an example, a row correlation coefficient between the first row projection vector and each second row projection vector, and a column correlation coefficient between the first column projection vector and each second column projection vector can be obtained, where the row correlation coefficient and the column correlation coefficient can be expressed as:

[0083]

[0084] Among them, SAD(Δx) is the row correlation coefficient; SAD(Δy) is the column correlation coefficient.

[0085] In some embodiments, the candidate row correlation coefficient with the largest value and the candidate column correlation coefficient with the largest value are screened from the row correlation coefficients and the column correlation coefficients; the row offset vector Δx corresponding to the candidate row correlation coefficient and the column offset vector Δy corresponding to the candidate column correlation coefficient are obtained, and the row offset vector Δx and the column offset vector Δy are used as the target image shift values (Δx, Δy) of the sequence image.

[0086] For further details on step S204, please refer to the relevant contents in the above embodiment, which will not be repeated here.

[0087] S205 , inputting the target image shift value into an optical sensitivity equation to obtain correction coefficients of the plane linear shift distance and the rotation angles of the three axes, wherein the correction coefficients are used to calibrate the optical sensitivity of the space camera flutter imaging model.

[0088] In some embodiments, the target image shift values (Δx, Δy) are input into the optical sensitivity equation for multiple regression analysis to obtain correction coefficients for the planar linear shift distance and the three-axis rotation angles. These correction coefficients are the correction values of a, b, c, d, and e. These correction coefficients are then used to calibrate the optical sensitivity of the space camera flutter imaging model.

[0089] For further details on step S205, please refer to the relevant contents in the above embodiment, which will not be repeated here.

[0090] In summary, the calibration method for the optical sensitivity of the space camera flutter imaging model provided in the embodiment of the present application, based on the design of the space camera, identifies the optical component with the largest surface shape change as the first optical component, and measures the plane linear movement distance and the rotation angle of the three axes of the first optical component within the time domain sampling interval, which helps to evaluate the dynamic performance of the optical component and the stability performance when subjected to external interference (such as vibration, temperature change, etc.); by determining the optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle, the impact of the movement and rotation of the optical component on the imaging quality can be effectively evaluated, and the behavior of the optical component under different conditions can be more accurately understood, so as to take corresponding measures to improve the stability of the space camera system; by inputting the determined target image shift value into the optical sensitivity equation, the correction coefficients of the plane linear movement distance and the rotation angle of the three axes are obtained. These correction coefficients are used to calibrate the optical sensitivity and correct the imaging error caused by the flutter of the space camera, thereby improving the imaging quality of the space camera and helping to enhance the stability of the space camera in complex environments.

[0091] Figure 3 A flowchart of another method for calibrating the optical sensitivity of a space camera flutter imaging model provided in an embodiment of the present application.

[0092] like Figure 3 As shown, the calibration method includes but is not limited to the following steps:

[0093] S301, obtaining a structural finite element model of a space camera.

[0094] S302 : Obtaining the three-dimensional displacement of each optical component in the space camera based on a time domain sampling interval according to the structural finite element model.

[0095] S303: Determine surface transformation data corresponding to the optical component according to each three-dimensional displacement.

[0096] S304: Obtain corresponding Zernike polynomial coefficients according to the surface transformation data corresponding to the optical component.

[0097] S305 , obtaining the first optical component with the largest surface shape change from all surface shape transformation data, and determining the plane linear movement distance and the rotation angles of the three axes of the first optical component in the three-dimensional space.

[0098] S306 , performing ray tracing on the structural data of the space camera and the coefficients of each Zernike polynomial to obtain an initial image shift value of the optical axis on the focal plane.

[0099] S307 , obtaining a time domain transformation curve of the plane linear movement distance and the rotation angle within the time domain sampling interval.

[0100] S308 , performing multiple regression analysis on the initial image shift value and the time domain transformation curve to obtain an optical sensitivity equation.

[0101] S309: Acquire a sequence image set of the space camera based on a time domain sampling interval.

[0102] S310: Determine target image shift values of the sequence images from a set of sequence images.

[0103] S311 , inputting the target image shift value into an optical sensitivity equation to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes, wherein the correction coefficients are used to calibrate the optical sensitivity of the space camera flutter imaging model.

[0104] For further details about steps S301 to S311, please refer to the relevant contents in the above embodiment, which will not be repeated here.

[0105] In summary, the calibration method for the optical sensitivity of the space camera flutter imaging model provided in the embodiment of the present application, based on the design of the space camera, identifies the optical component with the largest surface shape change as the first optical component, and measures the plane linear movement distance and the rotation angle of the three axes of the first optical component within the time domain sampling interval, which helps to evaluate the dynamic performance of the optical component and the stability performance when subjected to external interference (such as vibration, temperature change, etc.); by determining the optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle, the impact of the movement and rotation of the optical component on the imaging quality can be effectively evaluated, and the behavior of the optical component under different conditions can be more accurately understood, so as to take corresponding measures to improve the stability of the space camera system; by inputting the determined target image shift value into the optical sensitivity equation, the correction coefficients of the plane linear movement distance and the rotation angle of the three axes are obtained. These correction coefficients are used to calibrate the optical sensitivity and correct the imaging error caused by the flutter of the space camera, thereby improving the imaging quality of the space camera and helping to enhance the stability of the space camera in complex environments.

[0106] Figure 4 This is a schematic diagram of the structure of a device for calibrating the optical sensitivity of a space camera flutter imaging model provided by an embodiment of the present application. Figure 4 As shown, the optical sensitivity calibration device 400 of the space camera flutter imaging model includes:

[0107] A first acquisition module 401 is used to acquire a planar linear movement distance and three-axis rotation angles of a first optical component in three-dimensional space within a time domain sampling interval, wherein the first optical component is related to an optical component with the largest surface shape change in the space camera;

[0108] A second acquisition module 402 is used to determine an optical sensitivity equation corresponding to a plane linear movement distance and a rotation angle;

[0109] The third acquisition module 403 is used to determine the target image displacement value of the sequence image according to the sequence image set of the space camera in the time domain sampling interval;

[0110] The calibration module 404 is used to input the target image shift value into the optical sensitivity equation to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes, and calibrate the optical sensitivity of the space camera flutter imaging model based on the correction coefficients.

[0111] Figure 5 The figure is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. Figure 5 The electronic device shown is merely an example and should not limit the functions and scope of use of the embodiments of the present application.

[0112] like Figure 5 As shown, the electronic device 500 includes a processor 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a memory 506 into a random access memory (RAM) 503. Various programs and data required for the operation of the electronic device 500 are also stored in the RAM 503. The processor 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0113] The following components are connected to the I / O interface 505: a memory 506 including a hard disk, etc.; and a communication part 507 including a network interface card such as a LAN (Local Area Network) card, a modem, etc., which performs communication processing via a network such as the Internet; a drive 508 is also connected to the I / O interface 505 as needed.

[0114] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program carried on a computer-readable medium, which contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network via the communication section 507. When the computer program is executed by the processor 501, the above-mentioned functions defined in the method of the present application are performed.

[0115] In an exemplary embodiment, a storage medium including instructions is further provided, such as a memory including instructions, and the instructions can be executed by the processor 501 of the electronic device 500 to perform the above method. Alternatively, the storage medium can be a non-transitory computer-readable storage medium, such as a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0116] In this application, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. Furthermore, in this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wire, optical cable, RF, etc., or any suitable combination thereof.

[0117] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0118] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for calibrating the optical sensitivity of a space camera flutter imaging model, characterized in that: include: Obtaining a planar linear movement distance and three-axis rotation angles of a first optical component in three-dimensional space within a time domain sampling interval, wherein the first optical component is related to an optical component with the largest degree of surface shape change in the space camera; Determine an optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle; determining a target image shift value of a sequence of images according to a sequence of images of the space camera in the time domain sampling interval; The target image shift value is input into the optical sensitivity equation to obtain correction coefficients of the plane linear movement distance and the rotation angles of the three axes, wherein the correction coefficients are used to calibrate the optical sensitivity of the space camera flutter imaging model.

2. The method according to claim 1, characterized in that The obtaining of the planar linear movement distance of the first optical element in the three-dimensional space and the rotation angles of the three axes within the time domain sampling interval includes: Obtain the structural finite element model of the space camera; Obtaining, according to the structural finite element model, a three-dimensional displacement of each optical component in the space camera based on the time domain sampling interval; Determining surface transformation data corresponding to the optical component according to each of the three-dimensional displacements; Obtaining the first optical component with the largest degree of surface shape change from all the surface shape transformation data, and determining the plane linear movement distance and the rotation angles of the three axes of the first optical component in three-dimensional space; Among them, the plane linear movement distance includes a first linear movement distance along the X-axis direction and a second linear movement distance along the Y-axis direction; the rotation angle includes a first rotation angle around the X-axis, a second rotation angle around the Y-axis and a third rotation angle around the Z-axis.

3. The method according to claim 2, characterized in that Determining the surface transformation data corresponding to the optical component according to each of the three-dimensional displacements includes: Finite element analysis is performed on each of the three-dimensional displacements to obtain surface transformation data corresponding to the optical component, wherein the surface transformation data is based on the root mean square value and peak-to-peak value characterization of the surface deformation of the optical component.

4. The method according to claim 1, wherein The optical sensitivity equation for determining the plane linear movement distance and the rotation angle includes: Obtaining wavefront difference data of each optical component in the space camera according to the surface transformation data corresponding to the optical component; Fitting each of the wavefront difference data according to a least squares algorithm to obtain corresponding Zernike polynomial coefficients; Performing ray tracing on the structural data of the space camera and the coefficients of each of the Zernike polynomials to obtain an initial image shift value of the optical axis on the focal plane; Obtaining a time domain transformation curve of the plane linear movement distance and the rotation angle within a time domain sampling interval; Multiple regression analysis is performed on the initial image shift value and the time domain transformation curve to obtain the optical sensitivity equation.

5. The method according to claim 1, characterized in that The determining of the target image motion value of the sequence image according to the sequence image set of the space camera in the time domain sampling interval includes: Acquire a sequence image set of the space camera based on the time domain sampling interval; Determining a reference frame and at least one search frame from the sequence of images, and determining a reference area corresponding to the reference frame and a search area corresponding to the search frame; Obtaining a first row projection vector and a first column projection vector corresponding to the reference area, and a second row projection vector and a second column projection vector corresponding to the search area; The target image motion value is determined according to the first row projection vector, the first column projection vector, each second row projection vector, and each second column projection vector.

6. The method according to claim 5, characterized in that The first row projection vector and the first column projection vector corresponding to the reference area are determined using the following formula: Among them, r REF is the row position of the reference area; c REF is the column position of the reference area; ref (r REF ,c REF ) is the reference region (r REF ,c REF ) pixel grayscale value; M is the side length of the reference area; V REF (r REF ) is the reference area r REF Projection of the row; H REF (c REF ) is the reference area c REF Projection of column; V REF is the first row projection vector; H REF is the first column projection vector.

7. The method according to claim 5, characterized in that The determining the target image motion value according to the first row projection vector, the first column projection vector, each second row projection vector, and each second column projection vector includes: Obtaining a row correlation coefficient between the first row projection vector and each of the second row projection vectors, and a column correlation coefficient between the first column projection vector and each of the second column projection vectors; Selecting the candidate row correlation coefficient with the largest value and the candidate column correlation coefficient with the largest value from the row correlation coefficients and the column correlation coefficients; A row offset vector corresponding to the candidate row correlation coefficient and a column offset vector corresponding to the candidate column correlation coefficient are obtained, and the row offset vector and the column offset vector are used as target image shift values of the sequence image.

8. The method according to any one of claims 1 to 7, characterized in that Inputting the target image shift value into the optical sensitivity equation to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes includes: The target image shift value is input into the optical sensitivity equation for multiple regression analysis to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes.

9. A device for calibrating the optical sensitivity of a space camera flutter imaging model, characterized in that: include: A first acquisition module, configured to acquire a planar linear movement distance and three-axis rotation angles of a first optical component in three-dimensional space within a time domain sampling interval, wherein the first optical component is related to an optical component with the greatest degree of surface shape change in the space camera; a second acquisition module, the second acquisition module being used to determine an optical sensitivity equation corresponding to the plane linear movement distance and the rotation angle; a third acquisition module, configured to determine a target image shift value of a sequence of images according to a sequence of images of the space camera in the time domain sampling interval; A calibration module is configured to input the target image shift value into the optical sensitivity equation to obtain correction coefficients for the plane linear shift distance and the rotation angles of the three axes, and calibrate the optical sensitivity of the space camera flutter imaging model based on the correction coefficients.

10. An electronic device, characterized in that: include: processor; a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the method according to any one of claims 1 to 8.

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