A method for detecting wavefront error of a primary-secondary mirror optical system

Abstract

The present invention discloses a wavefront error detection method for a primary-secondary mirror optical system, belonging to the technical field of optical detection. Specifically, it includes: establishing a performance prediction model to calculate the ideal wavefront phase distribution; collecting a point spread function image through a detector, and using an iterative phase retrieval algorithm to retrieve the actual wavefront phase distribution; performing dynamic adaptive calibration to monitor and update the wavefront phase in real time, comparing the dynamically calibrated wavefront phase with the ideal wavefront phase, using an adaptive wavefront error compensation algorithm to calculate the error and predict the change trend. At the same time, an adaptive optics method is used to correct the wavefront error in real time; the above steps are repeated until the preset wavefront error threshold is met. The present invention improves the performance stability and accuracy of the primary-secondary mirror optical system and is applicable to the error correction of high-precision optical systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and specifically relates to a method for detecting wavefront error of a primary-secondary mirror optical system. Background Art

[0002] In an optical system, the primary-secondary mirror optical system is widely used in fields such as astronomical telescopes and high-resolution imaging systems. Wavefront error is one of the key indicators for measuring the imaging quality of an optical system. Accurately detecting the wavefront error of the primary-secondary mirror optical system is crucial for improving the performance of the optical system. Traditional wavefront error detection methods have problems such as low detection accuracy, complex detection processes, and high environmental requirements, making it difficult to meet the detection needs of modern high-precision optical systems.

[0003] For example, Chinese Patent with the authorization announcement number CN108225187B discloses a method for detecting aspherical lens errors based on wavefront sensing, including: obtaining the correspondence between the wavefront Zernike terms of the lens and the lens processing errors; based on the correspondence, using the actual wavefront of the aspherical lens to be measured to trace and detect the processing errors of the aspherical lens; wherein, the process of obtaining the correspondence specifically includes: taking several aspherical lens materials for analysis, respectively performing wavefront detection and simulation, and calculating the deviation between the actual and theoretical wavefronts of each aspherical lens material; according to the principle of approximate error distribution, performing systematic clustering and correlation analysis on multiple Zernike terms with unknown coefficients measured by wavefront simulation to determine the typical Zernike terms that can represent different processing errors. The method of this technical solution is a non-contact detection, which is convenient and fast, and the detection process is not affected by the subjective factors of the operator, and is relatively accurate; in particular, it can be used for real-time online error detection on the production line.

[0004] The above existing technologies have the following problems: mainly applicable to the production and quality control of aspherical lenses, resulting in limited application scope; tracing and detecting errors through the correspondence between wavefront Zernike terms and lens processing errors, although non-contact and fast, is not sensitive enough to certain specific types of processing errors and is difficult to accurately distinguish different types of error sources; lacking a dynamic feedback and adaptive adjustment mechanism. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention proposes a method for detecting wavefront errors in a primary-secondary mirror optical system, establishing a performance prediction model, and calculating the ideal wavefront phase distribution; collecting the point spread function image through a detector, and using the iterative phase retrieval algorithm to retrieve the actual wavefront phase distribution; performing dynamic adaptive calibration, monitoring and updating the wavefront phase in real time, comparing the dynamically calibrated wavefront phase with the ideal wavefront phase, using the adaptive wavefront error compensation algorithm to calculate the error and predict the change trend, and at the same time, using the adaptive optics method to correct the wavefront error in real time; repeating the above steps until the preset wavefront error threshold is met. The present invention improves the performance stability and accuracy of the primary-secondary mirror optical system and is applicable to the error correction of high-precision optical systems.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for detecting wavefront errors in a primary-secondary mirror optical system, comprising:

[0008] Step S1: Establish a performance prediction model for the primary-secondary mirror optical system;

[0009] Step S2: Based on the established performance prediction model of the primary-secondary mirror optical system, under the ideal condition of assuming that the optical system has no errors, calculate the ideal wavefront phase distribution at the focal plane after the target light source passes through the optical system;

[0010] Step S3: Place a detector at the focal plane of the optical system, collect the point spread function image of the target light source after passing through the optical system, and use the iterative phase retrieval algorithm to retrieve the actual wavefront phase distribution of the optical system according to the intensity information of the point spread function image;

[0011] Step S4: Based on the retrieved wavefront phase distribution, perform dynamic adaptive calibration. At the same time, monitor the change of the wavefront phase in real time and feedback it to the performance prediction model of the primary-secondary mirror optical system for updating, to obtain the updated performance prediction model of the primary-secondary mirror optical system and the dynamically calibrated wavefront phase distribution;

[0012] Step S5: Compare the dynamically calibrated wavefront phase distribution with the ideal wavefront phase distribution point by point, calculate the wavefront error, and predict the change trend of the wavefront error in combination with the updated performance prediction model of the primary-secondary mirror optical system;

[0013] Step S6: According to the prediction of the wavefront error and the change trend of the wavefront error, correct the wavefront error of the optical system in real time;

[0014] Step S7: Repeat Step S2 to Step S6 until the preset wavefront error threshold is met.

[0015] Specifically, the specific steps of Step S2 include:

[0016] S2.1: Determine the wavelength of the target light source and the amplitude distribution , where represents the amplitude distribution of the target light source on the initial plane , where and represent the abscissa and ordinate values of the initial plane respectively;

[0017] S2.2: According to the established performance prediction model of the primary and secondary mirror optical system, use the ray tracing method of geometric optics to calculate the propagation path of the rays emitted from the target light source to the surfaces of the primary and secondary mirrors;

[0018] S2.3: Continue to trace the rays, calculate the propagation path of the rays from the reflection of the primary and secondary mirrors to the focal plane and the propagation path of the rays after reflection to the focal plane, and obtain the intersection coordinates of the rays on the focal plane , where and represent the abscissa and ordinate values of the intersection of the rays on the focal plane respectively;

[0019] S2.4: For each traced ray, calculate the total optical path from the target light source, through the reflection of the primary and secondary mirrors, and finally to any point on the focal plane , and , N represents the number of rays emitted by the target light source;

[0020] S2.5: Select the optical path of a reference ray as the benchmark, and obtain the optical path difference of the i-th ray relative to the reference ray through difference calculation;

[0021] S2.6: According to the optical path difference , use the relationship between phase and optical path to calculate the phase at each point on the focal plane, where x and y represent the abscissa and ordinate values respectively;

[0022] S2.7: Organize the calculated phase values at each point on the focal plane into a two-dimensional array to obtain the ideal wavefront phase distribution of the target light source at the focal plane , and use drawing software to display the ideal wavefront phase distribution in the form of an image.

[0023] Specifically, the specific steps of the S2.2 include:

[0024] S2.21: Extract the primary mirror and secondary mirror parameters from the performance prediction model of the primary and secondary mirror optical system. The primary mirror and secondary mirror parameters include the radius of curvature, aperture, distance between the primary mirror and the secondary mirror, and vertex position coordinates of the primary mirror and the secondary mirror;

[0025] S2.22: Based on the property that light travels in a straight line in a homogeneous medium, establish the light propagation equation , where represents the position vector of the light ray, d represents the distance the light ray propagates from the initial point, represents the initial position vector of the light ray, represents the direction vector of the light ray, represents the position coordinates of the target light source, represents the vertical coordinate value of the target light source, represents the initial emission direction of the light ray;

[0026] S2.23: Take the spherical standard equation as the primary mirror equation, substitute the light propagation equation into the primary mirror equation, solve the quadratic equation system, and obtain the intersection coordinates of the light ray and the primary mirror , where , and respectively represent the abscissa, ordinate, and vertical coordinate values of the intersection point of the light ray and the primary mirror;

[0027] S2.24: At the intersection coordinates of the light ray and the primary mirror, obtain the normal vector of the primary mirror surface by taking the gradient of the primary mirror equation;

[0028] S2.25: According to the law of reflection, calculate the direction vector of the reflected light ray on the primary mirror surface from the direction vector of the incident light ray and the normal vector of the primary mirror surface;

[0029] S2.26: Take the intersection coordinates of the light ray and the primary mirror as the new starting point, and the direction vector of the reflected light ray on the primary mirror surface as the new direction, and update the light propagation equation to , where represents the distance the light ray propagates from the reflection point on the primary mirror, represents the intersection coordinates of the light ray and the primary mirror, that is, .

[0030] Specifically, the specific steps of S2.2 further include:

[0031] S2.27: Take the spherical standard equation as the secondary mirror equation, substitute the updated light propagation equation into the secondary mirror equation, solve the quadratic equation system, obtain the intersection coordinates of the light ray and the secondary mirror, and calculate the direction vector of the reflected light ray on the secondary mirror surface according to S2.24 - S2.25, where , and respectively represent the abscissa, ordinate and vertical coordinate values of the intersection point of the light ray and the secondary mirror;

[0032] S2.28: According to and , determine whether the light ray is on the mirror surface;

[0033] If , then the intersection point of the light ray and the primary mirror is within the aperture of the primary mirror;

[0034] If , then the intersection point of the light ray and the primary mirror is within the aperture of the secondary mirror;

[0035] S2.29: If the intersection point of the light ray and the primary mirror is within the aperture of the primary mirror and the intersection point of the light ray and the primary mirror is within the aperture of the secondary mirror, it means that the light ray is on the mirror surface;

[0036] If the light ray is on the mirror surface, record the propagation path of the light ray from the target light source, through reflection by the primary mirror, and then to the secondary mirror, including the position coordinates of the target light source, the intersection coordinates of the light ray and the primary mirror, the intersection coordinates of the light ray and the secondary mirror, and the corresponding reflected light direction vector.

[0037] Specifically, the specific steps of S2.3 include:

[0038] S2.31: Obtain the vertex position coordinates of the primary and secondary mirrors, and calculate the distance from the focal plane to the vertex of the primary mirror according to the vertex position coordinates of the primary and secondary mirrors and the distance formula from a point to a plane;

[0039] S2.32: Based on the distance from the focal plane to the vertex of the primary mirror, establish the focal plane equation ;

[0040] S2.33: Substitute the focal plane equation into the expression of the updated light ray propagation equation to obtain ;

[0041] S2.34: Substitute the calculated d value into the updated light ray propagation equation to obtain the intersection coordinates of the light ray on the focal plane.

[0042] Specifically, the specific steps of S2.4 include:

[0043] S2.41: During the light ray tracing process, based on the obtained position coordinates of the target light source, the intersection coordinates , the intersection coordinates of the light ray and the secondary mirror and the intersection coordinates of the light ray on the focal plane , using the distance formula between two points in space, calculate the geometric path from the target light source to the primary mirror , the geometric path from the primary mirror to the secondary mirror , and the geometric path from the secondary mirror to the focal plane ;

[0044] S2.42: By , , performing summation, obtain the total optical path of the i-th traced light ray .

[0045] Specifically, the specific steps of step S3 include:

[0046] S3.1: Place the detector at the focal plane of the optical system for image acquisition, and perform averaging on the acquired image to obtain the point spread function image of the target light source passing through the optical system ;

[0047] S3.2: Set the initial wavefront phase distribution , and combine the intensity information of the acquired point spread function image to construct the initial complex amplitude distribution ;

[0048] S3.3: Propagate the initial complex amplitude distribution through the forward propagation model of the optical system to an intermediate plane to obtain the complex amplitude distribution of the intermediate plane , where represents the coordinates of the intermediate plane;

[0049] S3.4: On the intermediate plane, correct the complex amplitude distribution according to the physical constraint conditions of the optical system, and propagate the corrected complex amplitude distribution of the intermediate plane back to the focal plane through the backward propagation model to obtain the new complex amplitude distribution of the focal plane .

[0050] Specifically, the specific steps of step S3 further include:

[0051] S3.5: Keep the phase information of the new complex amplitude distribution of the focal plane , and combine the intensity information of the acquired point spread function image to construct the updated complex amplitude distribution of the focal plane ;

[0052] S3.6: Calculate the difference MSE between the complex amplitude distributions obtained from two adjacent iterations using the mean square error formula;

[0053] S3.7: Set an error threshold ;

[0054] If , then take the updated complex amplitude distribution as the initial value for the next iteration, and return to S3.3 to continue the iteration;

[0055] If , then consider the iteration to have converged and terminate the iteration process;

[0056] S3.8: After the iteration terminates, the phase part of the finally obtained complex amplitude distribution is the actual wavefront phase distribution of the restored optical system.

[0057] Specifically, the specific steps of step S4 include:

[0058] S4.1: Obtain the actual wavefront phase distribution of the restored optical system and the primary and secondary mirror optical system performance prediction model;

[0059] S4.2: Determine the set of parameters that need to be dynamically adaptively calibrated according to the application requirements and performance indicators of the optical system;

[0060] S4.3: Based on optical theory, establish a mathematical model between the calibration parameters and the change in wavefront phase;

[0061] S4.4: Use the optical adjustment device to adjust the primary and secondary mirrors according to the preset calibration strategy, while real-time monitoring the change in wavefront phase and recording the initial data;

[0062] S4.5: Collect wavefront phase data at time intervals , compare the real-time monitored change in wavefront phase with the expected change in wavefront phase to obtain the wavefront phase difference , and calculate the feedback amount that needs to be fed back to the primary and secondary mirror optical system performance prediction model according to the wavefront phase difference through the PID control algorithm;

[0063] S4.6: Update the parameters of the primary and secondary mirror optical system performance prediction model according to the feedback amount, and use the updated parameters to recalculate and generate an updated primary and secondary mirror optical system performance prediction model, while recording the wavefront phase distribution after dynamic calibration .

[0064] Specifically, the specific steps of step S5 include:

[0065] S5.1: Obtain the wavefront phase distribution after dynamic calibration and the updated performance prediction model of the primary and secondary mirror optical systems, and set the ideal wavefront phase distribution ;

[0066] S5.2: For each coordinate point on the focal plane , compare the wavefront phase distribution after dynamic calibration with the ideal wavefront phase distribution through difference calculation to obtain the wavefront error , and perform mean analysis on the calculated wavefront error ;

[0067] S5.3: Combining the updated performance prediction model of the primary and secondary mirror optical systems, use the wavefront error information as input parameters, and utilize the optical propagation and transformation relationships in the updated performance prediction model of the primary and secondary mirror optical systems to predict the changing trend of the wavefront error under different time variations.

[0068] Compared with the prior art, the beneficial effects of the present invention are:

[0069] 1. The present invention proposes a wavefront error detection method for a primary and secondary mirror optical system. Through steps such as establishing a performance prediction model, restoring the actual wavefront phase distribution, and dynamic adaptive calibration, the method can monitor and accurately calculate the wavefront error of the primary and secondary mirror optical systems in real time, effectively improving the accuracy and stability of the optical system. Through this method, errors in the optical system can be detected and corrected in a timely manner to ensure that the optical system is always in the best working state.

[0070] 2. The present invention proposes a wavefront error detection method for a primary and secondary mirror optical system. The method also combines the prediction of the changing trend of the wavefront error to achieve continuous optimization of the performance of the optical system. By continuously iteratively updating the performance prediction model and the wavefront phase distribution, the method can gradually approach the ideal wavefront phase distribution until the preset wavefront error threshold is met, not only improving the performance of the optical system, but also reducing the maintenance cost and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 is a schematic diagram of a wavefront error detection method for a primary and secondary mirror optical system of the present invention;

[0072] Figure 2 is a principle flow chart of a wavefront error detection method for a primary and secondary mirror optical system of the present invention;

[0073] Figure 3This is a flowchart for implementing the propagation path of light rays reaching the primary and secondary mirror surfaces in a wavefront error detection method for a primary-secondary mirror optical system according to the present invention. Specific embodiments

[0074] Example 1

[0075] Please refer to Figure 1 and Figure 2 An example provided by the present invention: A wavefront error detection method for a primary-secondary mirror optical system includes the following steps:

[0076] Step S1: Establish a performance prediction model for the primary-secondary mirror optical system;

[0077] Furthermore, the specific process of establishing a performance prediction model for the primary-secondary mirror optical system includes:

[0078] (1) Determine the performance parameters and shape and size requirements of the primary-secondary mirror optical system according to the usage conditions;

[0079] (2) Draw up a schematic diagram of the optical system and determine the basic optical characteristics, such as magnification, focal length, linear field of view, and numerical aperture. This stage is usually carried out according to the theory of ideal optical systems;

[0080] (3) According to the primary aberration theory, solve the initial structure that meets the imaging quality requirements. Among them, the selection of the initial structure is the basis of lens design;

[0081] (4) Perform optical path calculations on the computer and use an aberration automatic correction program to correct aberrations;

[0082] (5) Draw aberration curves according to the calculation results, analyze the aberrations, find out the reasons, and perform repeated calculations and balancing until the imaging quality requirements are met;

[0083] (6) Based on the above design results, use the optical design software CODEV for model design to establish a performance prediction model for the primary-secondary mirror optical system. This model should be able to predict key performance parameters such as the imaging quality and wavefront phase distribution of the system;

[0084] (7) Conduct simulation analysis to verify the rationality and accuracy of the model, and evaluate the performance of the system according to the simulation results.

[0085] Step S2: Based on the established performance prediction model for the primary-secondary mirror optical system, under the ideal condition of assuming that the optical system has no errors, calculate the ideal wavefront phase distribution at the focal plane after the target light source passes through the optical system;

[0086] Step S3: Place a detector at the focal plane of the optical system, collect the point spread function image of the target light source passing through the optical system, and use the iterative phase retrieval algorithm to retrieve the actual wavefront phase distribution of the optical system based on the intensity information of the point spread function image;

[0087] Step S4: Based on the retrieved wavefront phase distribution, perform dynamic adaptive calibration. Meanwhile, monitor the change of the wavefront phase in real time and feedback it to the primary and secondary mirror optical system performance prediction model for update, obtaining the updated primary and secondary mirror optical system performance prediction model and the dynamically calibrated wavefront phase distribution;

[0088] Step S5: Compare the dynamically calibrated wavefront phase distribution with the ideal wavefront phase distribution point by point, calculate the wavefront error, and combine the updated primary and secondary mirror optical system performance prediction model to predict the changing trend of the wavefront error;

[0089] Step S6: According to the wavefront error and the prediction of the wavefront error changing trend, correct the wavefront error of the optical system in real time;

[0090] Furthermore, the specific steps of Step S6 include:

[0091] (1) Extract the wavefront error distribution data from the previous calculation results , which describes the difference between the actual wavefront phase and the ideal wavefront phase at each point on the focal plane;

[0092] (2) According to the prediction result of the wavefront error changing trend, judge the direction of the wavefront error changing with time, environmental factors or system internal parameters, clarify whether the error is increasing, decreasing or remaining stable, and the rate of change;

[0093] (3) Select adaptive optical elements according to the characteristics and changing trend of the wavefront error; The adaptive optical elements include:

[0094] Deformable mirror: Suitable for correcting high-order aberrations, and can compensate for complex wavefront error distributions by changing the mirror surface shape;

[0095] Tilt mirror: Mainly used to correct the overall tilt and low-order aberrations of the wavefront, and can quickly adjust the propagation direction of light;

[0096] Adjustable liquid lens: Can change its own curvature, perform continuous and local correction on the wavefront, and is often used to compensate for small aberrations and focusing errors;

[0097] (4) Use the least squares method to calculate the control parameters of the adaptive optical elements. Among them, the least squares method is the existing technical content in this field and is not the creative solution of this application, so it will not be elaborated here;

[0098] (5) Establish the mapping relationship between the wavefront error and the control parameters of the adaptive optical element. For example, for a deformable mirror, the relationship between the displacement of each actuator and the wavefront error can be obtained through optical simulation or experimental measurement;

[0099] (6) Solve the control parameters of the adaptive optical element according to the least squares method and the established mapping relationship. For example, use the least squares method to solve the driving voltage or displacement of each actuator of the deformable mirror;

[0100] (7) Convert the calculated control parameters into actual driving signals, such as voltage and current;

[0101] (8) Apply the driving signal to the adaptive optical element through the driver to cause corresponding physical changes, thereby correcting the wavefront error; the physical changes are such as mirror surface deformation and lens tilt;

[0102] (9) Use the wavefront sensor to monitor the corrected wavefront error in real time, and feedback the monitored new wavefront error data to the control algorithm, recalculate the control parameters and adjust the adaptive optical element to form a closed-loop control system, continuously optimize the correction effect until the wavefront error meets the preset threshold requirement.

[0103] Step S7: Repeat steps S2 to S6 until the preset wavefront error threshold is met.

[0104] Exemplarily, assume there is a primary and secondary mirror optical system for astronomical observation, with a primary mirror aperture of 2 meters, a secondary mirror aperture of 0.5 meters, and a focal length of 20 meters. According to the geometric parameters of the primary and secondary mirrors, such as the radius of curvature, aperture, and spacing, and the optical parameters, such as reflectivity, refractive index, etc., a mathematical model of the optical system is established; under the ideal condition of assuming no errors in the optical system, using the optical system performance prediction model, calculate the ideal wavefront phase distribution of a target light source, such as a star, at the focal plane after passing through the optical system; place a high-sensitivity CCD detector at the focal plane of the optical system to collect the point spread function image of the target light source after passing through the optical system. Due to the errors in the optical system, the PSF image will be distorted. Use the iterative phase retrieval algorithm to recover the actual wavefront phase distribution of the optical system based on the intensity information of the PSF image; based on the recovered wavefront phase distribution, perform dynamic adaptive calibration. For example, by real-time monitoring of environmental temperature changes and mirror deformation, adjust the model parameters. At the same time, feedback the monitored wavefront phase changes to the primary and secondary mirror optical system performance prediction model to update the model parameters, and obtain a more accurate performance prediction model and the wavefront phase distribution after dynamic calibration; compare the wavefront phase distribution after dynamic calibration with the ideal wavefront phase distribution point by point, use the adaptive wavefront error compensation algorithm to calculate the wavefront error. For example, calculate the root mean square error, and combine it with the updated primary and secondary mirror optical system performance prediction model to predict the trend of wavefront error changes with temperature. For example, predict that when the temperature increases by 5°C, the wavefront error will increase by 20%; according to the output results of the adaptive wavefront error compensation algorithm and the prediction of wavefront error changes, use adaptive optics methods to correct the wavefront error of the optical system in real time. For example, use a deformable mirror to adjust the mirror shape, or compensate for the wavefront error by adjusting the position and attitude of the secondary mirror; repeat steps S2 to S6, continuously monitor and correct the wavefront error until the wavefront error meets the preset threshold, such as the RMS value is less than λ / 20, where λ is the wavelength. For example, after multiple iterations, the wavefront error is reduced from the initial λ / 5 to λ / 25, meeting the requirements of astronomical observation.

[0105] Embodiment 2

[0106] The specific steps of step S2 in this embodiment include:

[0107] S2.1: Determine the wavelength and amplitude distribution of the target light source, where represents the amplitude distribution of the target light source on the initial plane , where and represent the abscissa and ordinate values of the initial plane respectively;

[0108] S2.2: According to the established performance prediction model of the primary and secondary mirror optical system, use the ray tracing method of geometric optics to calculate the propagation path of the rays emitted from the target light source to the surfaces of the primary and secondary mirrors;

[0109] S2.3: Continue to trace the rays, calculate the propagation path of the rays from the reflection of the primary and secondary mirrors to the focal plane and the propagation path of the rays after reflection to the focal plane, and obtain the intersection coordinates of the rays on the focal plane , where and respectively represent the abscissa and ordinate values of the intersection of the rays on the focal plane;

[0110] Among them, in the optical system, the focal plane is a specific two-dimensional plane. When considering the phase distribution on the focal plane, its essence is the two-dimensional distribution situation in this plane. Therefore, the z coordinate is a fixed value. For different points on the focal plane, the phase difference is mainly reflected in the changes in x and y, rather than z. Therefore, the intersection coordinates of the rays on the focal plane are expressed as .

[0111] S2.4: For each traced ray, calculate its total optical path from the target light source, through the reflection of the primary and secondary mirrors, and finally to any point on the focal plane , and , N represents the number of rays emitted by the target light source;

[0112] S2.5: Select the optical path of a reference ray as the benchmark, and obtain the optical path difference of the i-th ray relative to the reference ray through difference calculation;

[0113] S2.6: According to the optical path difference , use the relationship between phase and optical path to calculate the phase of each point on the focal plane, where x and y represent the abscissa and ordinate values respectively;

[0114] S2.7: Organize the phase values of each point on the calculated focal plane into a two-dimensional array to obtain the ideal wavefront phase distribution of the target light source at the focal plane , and use drawing software to display the ideal wavefront phase distribution in the form of an image.

[0115] Please refer to Figure 3 , the specific steps of the said S2.2 include:

[0116] S2.21: Extract the primary mirror and secondary mirror parameters from the performance prediction model of the primary and secondary mirror optical system. The primary mirror and secondary mirror parameters include the radius of curvature, aperture, distance between the primary mirror and the secondary mirror, and vertex position coordinates of the primary mirror and the secondary mirror;

[0117] S2.22: Establish the light propagation equation , where represents the position vector of the light ray, d represents the distance that the light ray propagates from the initial point, represents the initial position vector of the light ray, represents the direction vector of the light ray, represents the position coordinates of the target light source, represents the vertical coordinate value of the target light source, represents the initial emission direction of the light ray, and satisfies 、 and the sum of the squares of equals 1;

[0118] S2.23: Take the spherical standard equation as the primary mirror equation, substitute the light propagation equation into the primary mirror equation, solve the quadratic equation system, and obtain the intersection coordinates of the light ray and the primary mirror , where 、 and respectively represent the abscissa, ordinate, and vertical coordinate values of the intersection point of the light ray and the primary mirror. In the present invention, the spherical standard equation and the solution formula of the quadratic equation system are the prior art contents in the field and are not the creative solutions of this application, so they will not be elaborated here;

[0119] Among them, the formula of the spherical standard equation is: , where represents the center coordinates of the primary mirror, represents the radius of curvature of the primary mirror.

[0120] S2.24: At the intersection coordinates of the light ray and the primary mirror, obtain the normal vector of the primary mirror surface by taking the gradient of the primary mirror equation;

[0121] S2.25: According to the law of reflection, calculate the direction vector of the incident light ray and the normal vector of the primary mirror surface to obtain the direction vector of the reflected light ray on the primary mirror surface. Among them, the law of reflection is the prior art content in the field and is not the creative solution of this application, so it will not be elaborated here;

[0122] S2.26: Take the intersection coordinates of the light ray and the primary mirror as the new starting point, and the direction vector of the reflected light ray on the primary mirror surface as the new direction, and update the light propagation equation to , where represents the distance that the light ray propagates from the reflection point of the primary mirror, Indicates the intersection coordinates of the light ray and the primary mirror, that is ;

[0123] S2.27: Take the spherical standard equation as the secondary mirror equation, substitute the updated light ray propagation equation into the secondary mirror equation, solve the quadratic equation system, and obtain the intersection coordinates of the light ray and the secondary mirror , and calculate the direction vector of the reflected light ray on the surface of the secondary mirror according to S2.24 - S2.25 , where , and respectively represent the abscissa, ordinate and vertical coordinate values of the intersection point of the light ray and the secondary mirror, and the spherical standard equation adopts the spherical standard equation in S2.23;

[0124] S2.28: According to and , judge whether the light ray is on the mirror surface;

[0125] If , then the intersection point of the light ray and the primary mirror is within the aperture of the primary mirror;

[0126] If , then the intersection point of the light ray and the primary mirror is within the aperture of the secondary mirror;

[0127] Similarly, because the z coordinate is a fixed value when judging whether the light ray is on the mirror surface, it is not considered.

[0128] S2.29: If the intersection point of the light ray and the primary mirror is within the aperture of the primary mirror, and the intersection point of the light ray and the primary mirror is within the aperture of the secondary mirror, it means that the light ray is on the mirror surface;

[0129] If the light ray is on the mirror surface, record the propagation path of the light ray from the target light source, through reflection by the primary mirror, and then to the secondary mirror, including the position coordinates of the target light source, the intersection coordinates of the light ray and the primary mirror, the intersection coordinates of the light ray and the secondary mirror, and the corresponding direction vector of the reflected light ray.

[0130] The specific steps of the above S2.3 include:

[0131] S2.31: Obtain the vertex position coordinates of the primary and secondary mirrors, and calculate the distance from the focal plane to the vertex of the primary mirror according to the vertex position coordinates of the primary and secondary mirrors and the point-to-plane distance formula , where the point-to-plane distance formula is the prior art content in the field and is not the creative solution of this application, so it will not be elaborated here;

[0132] S2.32: Based on the distance from the focal plane to the vertex of the primary mirror, establish the focal plane equation ;

[0133] S2.33: Substitute the focal plane equation into the expression of the updated ray propagation equation to obtain ;

[0134] S2.34: Substitute the calculated value of d into the updated ray propagation equation to obtain the intersection coordinates of the ray on the focal plane .

[0135] The specific steps of S2.4 include:

[0136] S2.41: During the ray tracing process, based on the obtained position coordinates of the target light source , the intersection coordinates of the ray with the primary mirror , the intersection coordinates of the ray with the secondary mirror and the intersection coordinates of the ray on the focal plane , use the distance formula between two points in space to calculate the geometric path from the target light source to the primary mirror , the geometric path from the primary mirror to the secondary mirror , and the geometric path from the secondary mirror to the focal plane ;

[0137] Among them, the geometric path from the target light source to the primary mirror , the geometric path from the primary mirror to the secondary mirror , and the geometric path from the secondary mirror to the focal plane ;

[0138] S2.42: By summing up , , , obtain the total optical path of the i-th traced ray.

[0139] The specific steps of step S3 include:

[0140] S3.1: Place the detector at the focal plane of the optical system for image acquisition, and perform averaging on the acquired images to obtain the point spread function image of the target light source passing through the optical system ;

[0141] Furthermore, the specific steps of S3.1 include:

[0142] (1) First, build a suitable optical system according to the experimental requirements, ensure that each optical element is accurately installed and the optical path is stable, and calibrate the optical system using an optical measuring instrument for a standard light source. For example, adjust the focal length of the lens and align the optical axis to ensure that the light can be accurately focused on the focal plane;

[0143] (2) Place the detector at the focal plane position of the optical system through a mechanical adjustment device, and use an optical alignment tool to ensure that the photosensitive surface of the detector coincides exactly with the focal plane. At the same time, set the parameters of the detector, including exposure time, gain, and resolution; the detector is a CMOS camera; the exposure time should be reasonably adjusted according to the intensity of the target light source to avoid the image being too bright or too dark;

[0144] (3) Turn on the target light source so that the light emitted by it is focused on the detector after passing through the optical system. Among them, the detector converts the optical signal into an electrical signal or a digital signal to complete the acquisition of the image;

[0145] (4) Transmit the acquired image to the computer and process it using image processing software. Mainly perform numerical averaging calculation on the corresponding pixel points in each image to obtain the averaged image. For example, for the A images acquired, the pixel value at the coordinate, the result after averaging is the sum of the pixel values of all images at this coordinate divided by A;

[0146] (5) The image after averaging is the point spread function image of the target light source after passing through the optical system. The point spread function image reflects the diffusion effect of the optical system on a point light source, manifested as the light intensity distribution of the light source on the focal plane.

[0147] S3.2: Set the initial wavefront phase distribution , combined with the intensity information of the acquired point spread function image, construct the initial complex amplitude distribution , where, e represents the exponent, and j represents the imaginary part;

[0148] S3.3: Propagate the initial complex amplitude distribution through the forward propagation model of the optical system to an intermediate plane to obtain the complex amplitude distribution of the intermediate plane, where, represents the coordinates of the intermediate plane, F represents the Fourier transform, represents the inverse Fourier transform, represents the transfer function of Fresnel propagation;

[0149] S3.4: On the intermediate plane, correct the complex amplitude distribution according to the physical constraint conditions of the optical system, and propagate the corrected complex amplitude distribution of the intermediate plane back to the focal plane through the backward propagation model to obtain a new complex amplitude distribution of the focal plane;

[0150] S3.5: Keep the phase information of the new complex amplitude distribution and combine with the intensity information of the collected point spread function image to construct the updated complex amplitude distribution on the focal plane ;

[0151] S3.6: Calculate the difference MSE between the complex amplitude distributions obtained from two adjacent iterations using the mean square error formula. The mean square error formula is the prior art content in this field and not the creative solution of this application, so it will not be elaborated here;

[0152] S3.7: Set an error threshold ;

[0153] If , then use the updated complex amplitude distribution as the initial value for the next iteration, and return to S3.3 to continue the iteration;

[0154] If , then consider the iteration to converge and terminate the iteration process;

[0155] S3.8: After the iteration terminates, the phase part of the finally obtained complex amplitude distribution is the actual wavefront phase distribution of the restored optical system, where , where represents the phase information extraction function of the complex amplitude.

[0156] The specific steps of step S4 include:

[0157] S4.1: Obtain the actual wavefront phase distribution of the restored optical system and the main and secondary mirror optical system performance prediction model;

[0158] S4.2: Determine the parameter set that needs to be dynamically adaptively calibrated according to the application requirements and performance indicators of the optical system;

[0159] Further, the specific steps of S4.2 include:

[0160] (1) Clarify the usage scenario of the optical system. For example, is it used in the fields of astronomical observation, laser communication, or microscope imaging? Different application scenarios have very different performance requirements for the optical system. For example, astronomical observation may have higher requirements for resolution and light collection ability, while laser communication may pay more attention to beam pointing accuracy and energy concentration;

[0161] (2) Communicate with the experts of the user to determine the specific application requirements, such as quantitative indicators such as imaging clarity, target detection distance, and measurement accuracy;

[0162] (3) Translate the overall application requirements into specific optical performance indicators. For example, the imaging clarity of an imaging system can be measured by resolution, usually expressed as angular resolution or line resolution; the target detection distance may be related to indicators such as the optical flux and signal-to-noise ratio of the optical system.

[0163] (4) For each performance indicator, determine its acceptable range or specific numerical requirements. For example, an astronomical telescope requires an angular resolution of within 0.1 arcseconds.

[0164] (5) Study the working principle and structure of the optical system to determine which optical parameters will affect each performance indicator. For example, for a telescope system, parameters such as the curvature radius, aperture, and spacing of the primary mirror and secondary mirror will affect the focal length, aberration, etc. of the system, and thus affect the resolution and imaging quality; the refractive index, dispersion coefficient, etc. of the optical material will also act on the imaging.

[0165] (6) Establish qualitative and quantitative relationships between performance indicators and optical parameters by referring to optical design manuals. For example, according to the principles of geometric optics and physical optics, the resolution is related to the aperture and wavelength of the optical system and can be described by formulas such as the Rayleigh criterion.

[0166] (7) Based on the relationship between performance indicators and optical parameters, screen out the parameters that play a key role in meeting the application requirements and performance indicators. These parameters are the objects that need to be dynamically adaptively calibrated. For example, if the system has high requirements for resolution, then the surface shape parameters, relative position parameters, etc. of the primary mirror and secondary mirror may need to be dynamically adaptively calibrated.

[0167] (8) Considering the actual operability and cost factors, further optimize the initially determined parameter set, exclude those parameters that are difficult to measure or have too high adjustment costs, and finally determine a reasonable parameter set that can achieve dynamic adaptive calibration.

[0168] S4.3: Based on optical theory, establish a mathematical model between calibration parameters and wavefront phase changes.

[0169] Further, the specific steps of S4.3 include:

[0170] (1) Analyze in detail the structure of the studied optical system, clarify whether it is a refractive, reflective, or catadioptric type, etc., and determine the optical elements involved in wavefront phase changes, such as lenses and mirrors.

[0171] (2) Obtain the parameters that need to be dynamically adaptively calibrated, such as the curvature radius, thickness, and refractive index of the lens, and the surface shape parameters, tilt angle, and displacement of the mirror.

[0172] (3) According to the characteristics and working wavelength range of the optical system, select an optical theory to describe the wavefront propagation and phase change. For example, for large-sized optical elements and macroscopic optical paths in the category of geometric optics, ray tracing method and Fermat's principle can be adopted; for systems involving wave optics phenomena such as diffraction and interference, wave optics theories need to be used, such as Huygens - Fresnel principle and Kirchhoff diffraction formula. Among them, the optical theory is the existing technical content in this field and is not the creative solution of this application, so it will not be elaborated here;

[0173] (4) Based on the selected optical theory, analyze the propagation path and change situation of the wavefront in the optical system. For example, in the ray tracing method, calculate the incident angle, refraction angle, and reflection angle of the ray on the surface of each optical element, and determine the propagation direction and position change of the ray; in wave optics, consider the diffraction and interference effects of the wavefront when passing through apertures, obstacles, or passing through optical elements, and analyze the phase and amplitude changes of the wavefront;

[0174] (5) Based on the wavefront propagation analysis, establish a quantitative relationship between the calibration parameters and the wavefront phase change. Taking a lens as an example, according to the imaging formula of the lens and the phase delay principle, establish a mathematical expression between the parameters such as the curvature radius and thickness of the lens and the wavefront phase delay; for a mirror, according to the reflection law and the surface shape equation of the mirror surface, establish the relationship between the surface shape parameters, tilt angle, etc. of the mirror and the wavefront phase change. Among them, the imaging formula of the lens, the phase delay principle, the reflection law, and the surface shape equation of the mirror surface are all the existing technical content in this field and are not the creative solution of this application, so it will not be elaborated here;

[0175] (6) Verify the established mathematical model through experimental measurement or known standard data, and compare the model calculation result with the actually measured wavefront phase change to analyze the error source;

[0176] (7) According to the verification result, optimize and adjust the mathematical model, such as considering more optical effects, correcting the parameter value range, etc., to improve the accuracy and reliability of the model.

[0177] S4.4: Use the optical adjustment device to adjust the primary and secondary mirrors according to the preset calibration strategy, while real-time monitoring the change of the wavefront phase and recording the initial data;

[0178] S4.5: Collect the wavefront phase data at time intervals and compare the real-time monitored wavefront phase change amount with the expected wavefront phase change to obtain the wavefront phase difference , according to the wavefront phase difference, calculate the feedback amount that needs to be fed back to the performance prediction model of the primary and secondary mirror optical systems through the PID control algorithm, where, represents the real-time monitored wavefront phase distribution, It represents the expected wavefront phase distribution, and the PID control algorithm is the prior art content in the field and not the creative solution of this application, so it will not be elaborated here;

[0179] S4.6: According to the feedback quantity, update the parameters of the primary and secondary mirror optical system performance prediction model, and use the updated parameters to recalculate and generate the updated primary and secondary mirror optical system performance prediction model, and record the wavefront phase distribution after dynamic calibration 。

[0180] The specific steps of step S5 include:

[0181] S5.1: Obtain the wavefront phase distribution after dynamic calibration and the updated primary and secondary mirror optical system performance prediction model, and set the ideal wavefront phase distribution ;

[0182] S5.2: For each coordinate point on the focal plane , compare the wavefront phase distribution after dynamic calibration with the ideal wavefront phase distribution , obtain the wavefront error through difference calculation, and perform mean analysis on the calculated wavefront error ;

[0183] S5.3: Combining the updated primary and secondary mirror optical system performance prediction model, use the wavefront error information as input parameters, and use the optical propagation and transformation relationship in the updated primary and secondary mirror optical system performance prediction model to predict the change trend of the wavefront error under different time changes.

[0184] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make changes, modifications, substitutions, and variations to the above embodiments without departing from the purpose and scope of the present invention. These all fall within the protection scope of the present invention.

Claims

1. A method for detecting wavefront error of a primary-secondary mirror optical system, characterized in that Including: Step S1: Establish a performance prediction model for the primary and secondary mirror optical system; Step S2: Based on the established performance prediction model for the primary and secondary mirror optical system, calculate the ideal wavefront phase distribution at the focal plane after the target light source passes through the optical system under the ideal condition of assuming no error in the optical system; Step S3: Place a detector at the focal plane of the optical system, collect the point spread function image of the target light source passing through the optical system, and use the iterative phase retrieval algorithm to retrieve the actual wavefront phase distribution of the optical system according to the intensity information of the point spread function image; Step S4: On the basis of the retrieved wavefront phase distribution, perform dynamic adaptive calibration. At the same time, monitor the change of the wavefront phase in real time and feedback it to the performance prediction model of the primary and secondary mirror optical system for updating, obtaining the updated performance prediction model of the primary and secondary mirror optical system and the dynamically calibrated wavefront phase distribution; Step S5: Compare the dynamically calibrated wavefront phase distribution with the ideal wavefront phase distribution point by point, calculate the wavefront error, and combine the updated performance prediction model of the primary and secondary mirror optical system to predict the change trend of the wavefront error; Step S6: According to the prediction of the wavefront error and the change trend of the wavefront error, correct the wavefront error of the optical system in real time; Step S7: Repeat Step S2 to Step S6 until the preset wavefront error threshold is met; The specific steps of Step S4 include: S4.1: Obtain the actual wavefront phase distribution of the restored optical system and the performance prediction models of the primary and secondary mirror optical systems, where x and y represent the abscissa and ordinate values respectively; S4.2: Determine the parameter set that needs to be dynamically adaptively calibrated according to the application requirements and performance indicators of the optical system; S4.3: Based on optical theory, establish a mathematical model between the calibration parameters and the change of the wavefront phase; S4.4: Use the optical adjustment device to adjust the primary and secondary mirrors according to the preset calibration strategy, while monitoring the change of the wavefront phase in real time and recording the initial data; S4.5: At time intervals collect wavefront phase data, compare the real-time monitored wavefront phase change amount with the expected wavefront phase change to obtain a wavefront phase difference , and based on the wavefront phase difference, calculate the feedback amount to be fed back to the primary and secondary mirror optical system performance prediction model through the PID control algorithm; S4.6: Update the parameters of the primary and secondary mirror optical system performance prediction model according to the feedback amount, and recalculate and generate an updated primary and secondary mirror optical system performance prediction model using the updated parameters. Meanwhile, record the wavefront phase distribution after dynamic calibration .

2. The wavefront error detection method for the primary and secondary mirror optical system according to claim 1, wherein, The specific steps of Step S2 include: S2.1: Determine the wavelength of the target light source and the amplitude distribution , where represents the amplitude distribution of the target light source on the initial plane , where and represent the abscissa and ordinate values of the initial plane, respectively; S2.2: According to the established performance prediction model for the primary and secondary mirror optical system, use the ray tracing method of geometric optics to calculate the propagation path of the light rays emitted from the target light source to the surface of the primary and secondary mirrors; S2.3: Continue to trace the light ray, calculate the propagation path of the light ray from the primary and secondary mirrors to the focal plane after reflection and the propagation path of the light ray to the focal plane after reflection, and obtain the intersection coordinates of the light ray on the focal plane , where and respectively represent the abscissa and ordinate values of the intersection point of the light ray on the focal plane; S2.4: For each ray being traced, calculate the total optical path from the target light source, after being reflected by the primary and secondary mirrors, and finally reaching any point on the focal plane. , and , where N represents the number of rays emitted by the target light source; S2.5: Select the optical path of a reference ray As a reference, through difference calculation, obtain the optical path difference of the i-th ray relative to the reference ray ; S2.6: According to the optical path difference , calculate the phase of each point on the focal plane by using the relationship between the phase and the optical path ; S2.7: Organize the phase values of each point on the focal plane obtained by calculation into a two-dimensional array to obtain the ideal wavefront phase distribution of the target light source at the focal plane. And use drawing software to display the ideal wavefront phase distribution in the form of an image.

3. The wavefront error detection method for a primary-secondary mirror optical system according to claim 2, characterized in that, The specific steps of S2.2 include: S2.21: Extract the primary mirror and secondary mirror parameters from the performance prediction model of the primary and secondary mirror optical system. The primary mirror and secondary mirror parameters include the radius of curvature, aperture, distance between the primary mirror and the secondary mirror, and vertex position coordinates of the primary mirror and the secondary mirror; S2.22: Based on the property that light travels in a straight line in a uniform medium, establish the light propagation equation , where represents the position vector of the light ray, d represents the distance that the light ray propagates from the initial point, represents the initial position vector of the light ray, represents the direction vector of the light ray, represents the position coordinates of the target light source, represents the vertical coordinate value of the target light source, represents the initial emission direction of the light ray; S2.23: Take the standard equation of the spherical surface as the primary mirror equation, substitute the light propagation equation into the primary mirror equation, solve the quadratic equation system, and obtain the intersection coordinates of the light and the primary mirror , where , and respectively represent the abscissa, ordinate, and vertical coordinate values of the intersection point of the light and the primary mirror; S2.24: At the intersection coordinates of the light ray and the primary mirror the normal vector of the primary mirror surface is obtained by taking the gradient of the primary mirror equation ; S2.25: According to the law of reflection, the direction vector of the reflected light on the primary mirror surface is calculated from the direction vector of the incident light and the normal vector of the primary mirror surface to obtain the direction vector of the reflected light on the primary mirror surface ; S2.26: Take the intersection coordinates of the light ray and the primary mirror as the new starting point, and the direction vector of the reflected light ray on the surface of the primary mirror as the new direction, and update the light ray propagation equation to , where represents the distance that the light ray propagates from the reflection point of the primary mirror, represents the intersection coordinates of the light ray and the primary mirror, that is .

4. The wavefront error detection method for a primary-secondary mirror optical system according to claim 3, characterized in that, The specific steps of S2.2 also include: S2.27: Take the standard equation of the spherical surface as the equation of the secondary mirror, substitute the updated light propagation equation into the equation of the secondary mirror, solve the quadratic equation system, and obtain the intersection coordinates of the light and the secondary mirror , and calculate the direction vector of the reflected light on the surface of the secondary mirror according to S2.24 - S2.25 , where , and respectively represent the abscissa, ordinate and vertical coordinate values of the intersection point of the light and the secondary mirror; S2.28: According to and , determine whether the light is on the mirror surface; If , the intersection point of the light ray and the primary mirror is within the aperture of the primary mirror range; If , the intersection point of the light ray and the primary mirror is within the aperture of the secondary mirror ; S2.29: If the intersection point of the light ray and the primary mirror is within the aperture of the primary mirror range, and the intersection point of the light ray and the primary mirror is within the aperture of the secondary mirror range, it means that the light ray is on the mirror surface; If the light ray is on the mirror surface, record the propagation path of the light ray from the target light source, reflected by the primary mirror, and then to the secondary mirror, including the target light source position coordinates, the intersection coordinates of the light ray and the primary mirror, the intersection coordinates of the light ray and the secondary mirror, and the corresponding reflected light ray direction vector.

5. The wavefront error detection method for a primary-secondary mirror optical system according to claim 4, characterized in that The specific steps of S2.3 include: S2.31: Obtain the vertex position coordinates of the primary and secondary mirrors, and calculate the distance from the focal plane to the vertex of the primary mirror according to the vertex position coordinates of the primary and secondary mirrors and the distance formula from a point to a plane ; S2.32: Establish the focal plane equation based on the distance from the focal plane to the vertex of the primary mirror ; S2.33: Substitute the focal plane equation into the expression of the updated light propagation equation to obtain ; S2.34: Substitute the calculated value of d into the updated light propagation equation to obtain the intersection coordinates of the light on the focal plane .

6. The wavefront error detection method for a primary-secondary mirror optical system according to claim 5, wherein The specific steps of S2.4 include: S2.41: During the ray tracing process, based on the obtained position coordinates of the target light source , the intersection coordinates of the ray and the primary mirror , the intersection coordinates of the ray and the secondary mirror and the intersection coordinates of the ray on the focal plane , use the distance formula between two points in space to calculate the geometric path from the target light source to the primary mirror , the geometric path from the primary mirror to the secondary mirror , the geometric path from the secondary mirror to the focal plane ; S2.42: By summing up , , , the total optical path of the i-th traced ray is obtained.

7. The wavefront error detection method for the primary and secondary mirror optical system according to claim 6, wherein The specific steps of Step S3 include: S3.1: Place the detector at the focal plane of the optical system for image acquisition, and perform averaging processing on the acquired images to obtain the point spread function image of the target light source after passing through the optical system ; S3.2: Set the initial wavefront phase distribution , and construct the initial complex amplitude distribution by combining the intensity information of the collected point spread function image ; S3.3: Propagate the initial complex amplitude distribution to an intermediate plane through the forward propagation model of the optical system to obtain the complex amplitude distribution of the intermediate plane , where represents the coordinates of the intermediate plane; S3.4: On the intermediate plane, correct the complex amplitude distribution according to the physical constraints of the optical system and propagate the corrected complex amplitude distribution on the intermediate plane back to the focal plane through the backpropagation model to obtain a new complex amplitude distribution on the focal plane .

8. A wavefront error detection method for a primary-secondary mirror optical system according to claim 7, characterized in that The specific steps of Step S3 also include: S3.5: Maintain the phase information of the new focal plane complex amplitude distribution and combine it with the intensity information of the acquired point spread function image to construct an updated focal plane complex amplitude distribution ; ; S3.6: Use the mean square error formula to calculate the difference MSE between the complex amplitude distributions obtained from two adjacent iterations; S3.7: Set an error threshold ; If , then use the updated complex amplitude distribution as the initial value for the next iteration, and return to S3.3 to continue the iteration; If , it is considered that the iteration converges and the iteration process is terminated; S3.8: After the iteration terminates, the phase part of the finally obtained complex amplitude distribution is the actual wavefront phase distribution of the restored optical system.

9. The wavefront error detection method for a primary-secondary mirror optical system according to claim 8, characterized in that, The specific steps of Step S5 include: S5.1: Obtain the wavefront phase distribution after dynamic calibration and the updated performance prediction model of the primary and secondary mirror optical systems, and set the ideal wavefront phase distribution ; S5.2: For each coordinate point on the focal plane , compare the wavefront phase distribution after dynamic calibration with the ideal wavefront phase distribution , obtain the wavefront error through difference calculation , and perform mean analysis on the calculated wavefront error . S5.3: Combine the updated performance prediction model of the primary and secondary mirror optical systems, and use the wavefront error information as input parameters. Utilize the optical propagation and transformation relationships in the updated performance prediction model of the primary and secondary mirror optical systems to predict the changing trend of the wavefront error under different time variations.

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