Optical system wave aberration acquisition method based on generalized pupil function

Abstract

The invention discloses an optical system wave aberration acquisition method based on a generalized pupil function, and belongs to the technical field of imaging quality detection of optical systems. The problems that in the prior art, due to the fact that exit pupil deformation adaptability is insufficient, off-axis view field wave aberration calculation deviation is large, and it is difficult to be suitable for on-axis and off-axis view field wave aberration calculation at the same time are solved. The method comprises the following steps: acquiring an incident wavelength and a field angle of a to-be-detected optical system; obtaining entrance pupil and exit pupil parameters, and determining an entrance pupil position, an entrance pupil diameter and a corresponding exit pupil position by using a paraxial ray tracing algorithm; determining the working F number TFNO in the meridian direction and the F number SFNO in the sagittal direction under the wavelength and the field angle; obtaining a normalized pupil plane according to the TFNO and the SFNO; further generating an incident light array; tracing the incident ray array to an image surface according to an actual ray tracing algorithm; determining a virtual reference spherical surface parameter; and optical system wave aberration is obtained. The method can be applied to the technical field of optical system design.

Description

Technical Field

[0001] This invention belongs to the field of imaging quality detection technology for optical systems and is applied to the field of optical system design technology. Background Technology

[0002] In the imaging quality analysis of optical systems, wavefront aberration is an important indicator for evaluating the system's imaging performance. Accurate methods for obtaining wavefront aberration are of great significance for the design optimization, tolerance analysis, and imaging performance prediction of optical systems.

[0003] In existing technologies, wavefront aberration of optical systems is solved using methods based on ray tracing and the standard pupil function. Chinese patent document CN116296279A describes a method for solving wavefront aberration of optical systems using ray tracing. This method obtains the system's wavefront aberration by uniformly sampling light rays within the entrance pupil plane and calculating the optical path difference between the actual wavefront formed by the sampled rays and the reference wavefront. This method can solve the problem of wavefront aberration calculation for optical systems in on-axis fields of view and, under limited conditions (i.e., a small field of view angle, where the resulting exit pupil distortion is negligible), can be extended to the analysis of part of the off-axis field of view.

[0004] The aforementioned existing technology has the following technical problems: 1. Insufficient adaptability to exit pupil distortion: In off-axis fields of view, the exit pupil of an optical system no longer maintains a standard circle, but often appears as an ellipse. Traditional methods assume a circular pupil for sampling, resulting in a significant deviation between the calculated wavelet aberrations and the actual wavelet aberration distribution.

[0005] 2. Insufficient uniformity in calculation: Existing technologies lack a unified mathematical framework, and the calculation process is complex. Currently, there is no generalized analysis method for wave aberrations of optical systems that is applicable to both on-axis and off-axis fields of view. Summary of the Invention

[0006] The present invention aims to solve the problems in the prior art, such as large deviations in the calculation of off-axis field wave aberrations due to insufficient adaptability of exit pupil deformation, and the lack of a unified mathematical framework, which makes it difficult to apply to the calculation of both on-axis and off-axis field wave aberrations.

[0007] The technical solution adopted by this invention to solve the technical problem is as follows: Step 1: Obtain the incident wavelength λ and field of view of the optical system to be tested. ω x , ω y ); Step two: obtaining the entrance pupil and exit pupil parameters, according to the structure parameters of the optical system and the position of the aperture stop, the paraxial ray tracing algorithm is used to determine the entrance pupil position ENPP and the entrance pupil diameter ENPD; further determine the corresponding exit pupil position EXPP, the exit pupil position EXPP refers to the exit pupil relative to the image plane z to the displacement; Step three: determining the meridional working F number TFNO and sagittal F number SFNO at the wavelength λ and field angle (θ, φ) ω x , ω y ; Step four: according to the TFNO and SFNO, solving the normalized transmission aperture, and further obtaining the normalized pupil plane; Step five: uniformly sampling in the normalized pupil plane to obtain sampling points, and generating an incident ray array according to the ENPD, ENPP and field angle (θ, φ) ω x , ω y ; Step six: according to the actual ray tracing algorithm, tracing the incident ray array to the image plane; Step seven: determining the virtual reference spherical surface parameters; Step eight: obtaining the wave aberration of the optical system.

[0008] Preferably, the method for determining the meridional working F number TFNO and sagittal F number SFNO in step three comprises: Step S3.1: according to the actual ray tracing algorithm, obtaining three direction vectors in the meridional plane of the optical system to be detected at the wavelength λ and field angle (θ, φ) ω x , ω y : the unit direction vector of the upper edge ray propagating to the image plane , the unit direction vector of the lower edge ray propagating to the image plane , the unit direction vector of the chief ray propagating to the image plane ; Step S3.2: using the three direction vectors obtained in step S3.1, obtaining two included angles in the meridional plane: the included angle of the upper edge ray relative to the chief ray θ T,UP , the included angle of the lower edge ray relative to the chief ray θ T,DOWN ; Step S3.3: according to (1) , the meridional working F number TFNO is obtained, whereinn the like-side refractive index; Step S3.4: According to the method described in steps S3.1 to S3.3, the left and right edge rays in the sagittal plane are traced, the included angles of the left and right edge rays with respect to the chief ray are calculated, and the sagittal direction F number SFNO is obtained according to the two included angles.

[0009] Preferably, the process of obtaining the normalized transmission aperture in step four is as follows: Step S4.1: According to the TFNO and SFNO, the normalized aperture boundary equation under the wavelength λ and the field of view angle (θ, φ) is determined: ω x , ω y ) is determined: (2) In the formula, P x , P y is the coordinate in the normalized pupil plane of the optical system, and its domain is in the interval [-1, 1]; the aperture boundary is determined according to the above equation; Step S4.2: A normalized pupil coordinate plane is created, and the region within the aperture boundary determined in step S4.1 is the transmission aperture region, which is the effective pupil range of the optical system under the on-axis or off-axis field of view, and the pupil refers to the entrance pupil and the exit pupil.

[0010] Preferably, the method of generating an incident ray array in step five includes: Step S5.1: Uniformly sampling in the normalized pupil plane according to a set resolution to obtain a series of sampling points; Step S5.2: According to the series of sampling points and the entrance pupil diameter ENPD and the entrance pupil position ENPP, the starting point of each incident ray in the global coordinate system is determined, and according to the field of view angle (θ, φ), the unit direction vector of each incident ray is obtained, and all incident rays constitute an incident ray array. ω x , ω y ) is obtained. (3)

[0011] Preferably, the process of tracing the incident ray array to the image plane according to the actual ray tracing algorithm in step six includes: Step S6.1: Input the incident ray array generated in step five into the optical system model; Step S6.2: Calculate the propagation path of each ray in the incident ray array through the optical system by the actual ray tracing algorithm.​ Step S6.3: According to the obtained all propagation paths, the intersection position of each light ray on the image plane, the unit direction vector and its actual optical path information are obtained, and the actual optical path of all light rays constitutes a matrix OPTH MT ; Step S6.4: According to steps S6.1 to S6.3, the intersection position of the main light ray on the image plane, the unit direction vector and its actual optical path information are solved by using the actual ray tracing algorithm, and the actual optical path of the main light ray is OPTH CR .

[0012] Preferably, the determination of the virtual reference spherical surface parameter in step seven is obtained by referring to the spherical surface equation: (4) Solving obtains; in the equation, x CR , y CR , z CR ) is the coordinate of the main light ray in the image plane under the global coordinate system; R is the radius of the virtual reference spherical surface, and is: (5) In the equation is the z projection component of the unit direction vector of the main light ray at the image plane.

[0013] Preferably, the specific method for obtaining the wave aberration of the optical system in step eight is as follows: Step S8.1: Establishing a ray equation; According to the actual ray tracing result, the straight line equation of any light ray in the incident light ray array under the global coordinate system is: (6) represents the optical path, and x real , y real , z real ) is the image plane coordinate of each array light ray in the incident light ray array under the global coordinate system, and k x,real , k y,real , k z,real ) is the unit direction vector of the array light ray in the image plane x , y , zProjections in three directions; Step S8.2: obtaining the optical path of each array light from the image surface to the reference sphere according to the straight line equation and the reference sphere equation t For the case that the exit pupil center does not coincide with the image surface, the inner product between the direction vector of the array light and the radius vector of the Gaussian image point to the exit pupil center is calculated, if the inner product result is positive, the solution of t>0 is taken, otherwise the solution of t<0 is taken; the matrix composed of the optical paths of all array lights from the image surface to the reference sphere is recorded as T Step S8.3: solving the optical path of the chief ray from the image surface to the reference sphere According to the chief ray tracing result, the chief ray optical path of the chief ray from the image surface to the reference sphere is solved t CR Step S8.4: solving the two-dimensional distribution of the wave aberration in the paraxial exit pupil plane (7) The two-dimensional distribution of the wave aberration in the paraxial exit pupil plane is obtained.

[0014] The beneficial effects of the present application compared with the prior art are: Through the technical scheme provided by the present application, the wave aberration of the full field of view range can be accurately calculated in a unified mathematical framework, which improves the calculation integrity and efficiency, and enhances the adaptability to the exit pupil deformation, thereby providing a more reliable theory and calculation tool for the design and optimization of the optical system.

[0015] (1) The optical system wave aberration acquisition method based on the generalized pupil function provided by the present application is realized by ray tracing (i.e. tracking the path of the light ray), calculating the wave aberration in the generalized pupil function under the condition of a specific wavelength and a specific field of view of the optical system.

[0016] (2) In the method provided by the present application, the principle of combining ray tracing and coordinate scaling is adopted, which solves the problem of insufficient adaptability of the exit pupil deformation.

[0017] The normalized coordinate definition, unified sampling, unified tracing and unified output of the method provided by the present application simultaneously satisfy the wave aberration calculation in the exit pupil plane under the on-axis field of view and the off-axis field of view in a unified mathematical framework.

[0018] The wave aberration obtained by the method provided by the present application can be directly used to accurately calculate the performance indicators such as PSF and MTF of the optical system in the research and development process of the optical system, and then the optical system is optimized and designed based on these performance indicators.

[0019] ​​​(3) The calculation method provided by the application solves the problem of insufficient uniformity of calculation, and provides a generalized analysis method for wavefront aberration calculation of an exit pupil plane of an optical system. Compared with the existing calculation method, the calculation accuracy and universality of the method are significantly improved, and the method is more reliable for performance analysis of the optical system in the optical design process.

[0020] The method has the advantages of wide application range and strong robustness, and can be applied to wavefront aberration analysis of various optical systems. According to the analysis result, the design scheme of the optical system can be quickly optimized without testing experiments, thereby reducing the research and design cost of optical design. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a flowchart of the optical system wavefront aberration acquisition method based on the generalized pupil function.

[0022] Figure 2 is a ray path schematic diagram according to the structure parameters of a certain type of seeker optical system in step eight wavefront aberration calculation in the eighth embodiment.

[0023] Figure 3 is the two-dimensional distribution result schematic diagram of the exit pupil plane wavefront aberration solved by the method in the eighth embodiment. Figure 2 is the two-dimensional distribution result schematic diagram of the exit pupil plane wavefront aberration solved by the method in the eighth embodiment.

[0024] Figure 4 is the two-dimensional distribution result schematic diagram of the exit pupil plane wavefront aberration solved by the method in the eighth embodiment. EMBODIMENT

[0025] Embodiment I, see Figure 1 The embodiment is described.

[0026] The optical system wavefront aberration acquisition method based on the generalized pupil function includes the following steps: Step one: obtaining the wavelength λ and the field angle (θ, φ) of the optical system to be detected ω x , ω y ); Step two: obtaining the entrance pupil and exit pupil parameters, according to the structure parameters of the optical system and the position of the aperture diaphragm, using the paraxial ray tracing algorithm to determine the entrance pupil position ENPP and the entrance pupil diameter ENPD; further determine the corresponding exit pupil position EXPP, the exit pupil position EXPP refers to the z displacement of the exit pupil relative to the image plane; Step three: determining the wavefront aberration of the optical system at the wavelength λ and the field angle (θ, φ)ω x , ω y ) and sagittal F-number SFNO; Step four: according to the TFNO and SFNO, solving the normalized transmission aperture, and then obtaining the normalized pupil plane; Step five: uniformly sampling in the normalized pupil plane to obtain sampling points, and generating an incident ray array according to the ENPD, ENPP and field of view ( ω x , ω y ) ; Step six: according to the actual ray tracing algorithm, tracing the incident ray array to the image plane; Step seven: determining the virtual reference spherical surface parameters; Step eight: obtaining the optical system wave aberration.

[0027] The optical system wave aberration solving method described in the embodiment is realized by a ray tracing method, that is, the wave aberration in the generalized pupil function of the optical system under a specific wavelength and a specific field of view is calculated by tracing the ray path. In the embodiment, according to the optical system structure parameters and the position of the aperture diaphragm, the paraxial ray tracing algorithm is used to determine the entrance pupil position ENPP and the entrance pupil diameter ENPD; the corresponding exit pupil position EXPP is further determined, so as to introduce the reference spherical surface in the subsequent wave aberration calculation.

[0028] Embodiment two, the embodiment is a preferred solution of step three of the optical system wave aberration obtaining method described in embodiment one. The method for determining the meridional working F-number TFNO and the sagittal F-number SFNO described in step three of the embodiment includes: Step S3.1: according to the actual ray tracing algorithm, obtaining three direction vectors in the meridional plane of the optical system to be detected under the wavelength λ and the field of view ( ω x , ω y ), including the unit direction vector of the upper edge ray propagating to the image plane , the unit direction vector of the lower edge ray propagating to the image plane , and the unit direction vector of the chief ray propagating to the image plane ; Step S3.2: using the three direction vectors obtained in step S3.1, obtaining two included angles in the meridional plane: the included angle θ T,UP of the upper edge ray relative to the chief ray θ T,DOWN ; Step S3.3: obtaining the meridional working F-number TFNO, wherein (1) obtaining the sagittal working F-number SFNO, wherein n is the image-side refractive index; Step S3.4: tracing the left and right marginal rays in the sagittal plane according to the method described in steps S3.1 to S3.3, calculating the included angles of the left and right marginal rays with respect to the chief ray respectively, and obtaining the sagittal F-number SFNO according to the two included angles.

[0029] In the present embodiment, the meridional plane refers to a plane formed by the chief ray of an off-axis object point and the principal axis of the optical system.

[0030] In the present embodiment, the left and right marginal rays mentioned in the process of obtaining SFNO in step S3.4 are defined with respect to the chief ray in the sagittal plane.

[0031] Embodiment three, the present embodiment is a preferred solution of step four in the method for obtaining wavefront aberration of the optical system described in embodiment one, and the process for obtaining the normalized transmission aperture in step four is as follows: Step S4.1: determining the normalized aperture boundary equation under the wavelength λ and the field of view angle (θx, θy) according to the TFNO and SFNO: ω x , ω y wherein (2) wherein P x , P y is the coordinate in the normalized pupil plane of the optical system, and the definition domain is in the interval [-1, 1]; and the aperture boundary is determined according to the above equation; Step S4.2: creating a normalized pupil coordinate plane, and taking the area within the aperture boundary determined in step S4.1 as the transmission aperture area, wherein the transmission aperture area is the effective pupil range of the optical system under the on-axis or off-axis field of view, and the pupil refers to the entrance pupil and the exit pupil.

[0032] In the present embodiment, the on-axis field of view satisfies the mathematical relationship TFNO=SFNO, and the normalized circular pupil corresponding to the on-axis field of view still satisfies the above normalized aperture boundary equation, which is a general mathematical expression equation of the generalized pupil aperture.

[0033] In the present embodiment, the transmission aperture area in step S4.2 is used to describe the effective pupil range of the optical system under the field of view, and the pupil refers to the entrance pupil and the exit pupil.

[0034] In the embodiment, the normalized pupil coordinate plane is a mathematical two-dimensional coordinate system. The plane is used to uniformly describe the geometry and size of the entrance pupil and exit pupil of the optical system.

[0035] Embodiment four, the embodiment is the preferred solution of step five of the optical system wave aberration acquisition method described in embodiment one, the method of generating the incident light array in step five includes: Step S5.1: uniformly sampling in the normalized pupil plane according to the set resolution to obtain a series of sampling points; Step S5.2: determining the starting point of each incident light in the global coordinate system according to the series of sampling points and the entrance pupil diameter ENPD and the entrance pupil position ENPP, and determining the starting point of each incident light in the global coordinate system according to the field of view angle (θ, φ) and the unit direction vector of each incident light, and all the incident lights constitute the incident light array. ω x , ω y ), according to the unit direction vector of each incident light, and all the incident lights constitute the incident light array. (3) Obtain the unit direction vector of each incident light, and all the incident lights constitute the incident light array.

[0036] The global coordinate system in the embodiment is a coordinate system for the optical system, and the origin of the coordinate system is located at the vertex of the first optical surface of the optical system; the Z-axis coincides with the optical axis of the optical system, and the positive direction is the propagation direction of the light; the X-axis and the Y-axis constitute a plane perpendicular to the optical axis, and the plane is a right-handed coordinate system.

[0037] Embodiment five, the embodiment is the preferred solution of step six of the optical system wave aberration acquisition method described in embodiment one, and the process of tracing the incident light array to the image plane according to the actual ray tracing algorithm in step six includes: Step S6.1: inputting the incident light array generated in step five into the optical system model; Step S6.2: calculating the propagation path of each light in the incident light array through the optical system by the actual ray tracing algorithm; Step S6.3: obtaining the intersection position, unit direction vector and actual optical path information of each light on the image plane according to all the propagation paths, and the actual optical paths of all the lights constitute a matrix OPTH MT ; Step S6.4: according to steps S6.1 to S6.3, solving the intersection position, unit direction vector and actual optical path information of the chief ray on the image plane by using the actual ray tracing algorithm, and the actual optical path of the chief ray is OPTH CR .

[0038] Embodiment six, the embodiment is the preferred scheme of step seven in the optical system wave aberration acquisition method of embodiment one, step seven determines the virtual reference spherical surface parameter by the reference spherical surface equation: (4) solving obtains; in the equation, x CR , y CR , z CR ) is the coordinate of the chief ray in the image plane in the global coordinate system; R is the radius of the virtual reference spherical surface, and is: , (5) in the equation is the z projection component of the unit direction vector of the chief ray at the image plane.

[0039] Embodiment seven, the embodiment is the preferred scheme of step eight in the optical system wave aberration acquisition method of embodiment one, and the specific method for obtaining the optical system wave aberration in step eight is as follows: Step S8.1: establishing a ray equation; According to the actual ray tracing result, the straight line equation of any ray in the incident light ray array in the global coordinate system is: (6) represents the optical path, ( x real , y real , z real ) is the image plane coordinate of each array ray in the incident light ray array in the global coordinate system, ( k x,real , k y,real , k z,real ) is the projection of the unit direction vector of the array ray in the image plane in x , y , z three directions; Step S8.2: according to the straight line equation and the reference spherical surface equation, the optical path of each array ray from the image plane to the reference spherical surface t is obtained; For the case that the exit pupil does not coincide with the image plane, the inner product between the direction vector of the array light and the radius vector from the Gaussian image point to the center of the exit pupil is calculated. If the inner product result is positive, the solution of t>0 is taken, otherwise the solution of t<0 is taken. The matrix composed of the optical path from the image plane to the reference sphere of all array lights is denoted as T ; Step S8.3: solving the optical path of the chief ray from the image plane to the reference sphere; According to the chief ray tracing result, the chief ray optical path of the chief ray from the image plane to the reference sphere is solved t CR ; Step S8.4: solving the two-dimensional distribution of the wavefront aberration in the paraxial exit pupil plane: (7) The two-dimensional distribution of the wavefront aberration in the paraxial exit pupil plane is obtained.

[0040] In the field, the essence of the wavefront aberration of an optical system is the optical path difference between the actual wavefront and the ideal reference wavefront, which is a principle known in the field, but in practical application, there are certain difficulties in obtaining the physical quantity, especially in the off-axis field of view, due to the influence of exit pupil deformation and aberration complexity, which has led to the fact that accurate calculation in a unified mathematical framework has not been realized so far. The present embodiment realizes accurate calculation of the wavefront aberration in the on-axis and off-axis field of view in a unified mathematical framework. In the present embodiment, the optical path of any light in the light array from the image plane to the reference sphere t is obtained by solving the straight line equation and the reference sphere equation, and the solving method obtained after being solved together is a quadratic equation: , Among them: .(8) The wavefront aberration in the paraxial exit pupil plane described in formula 7 is the sum of the absolute optical path and the correction optical path, wherein the absolute optical path is the difference between the optical path of the chief ray from the object point to the image plane and the optical path of the tracing light from the object point to the image plane, and the correction optical path is the difference between the optical path of the chief ray from the image plane to the reference sphere and the optical path of the tracing light from the image plane to the reference sphere.

[0041] Embodiment eight, the present embodiment illustrates that the optical system wavefront aberration acquisition method described in the present application is realizable: The present embodiment is according to the structure parameters of a certain type of seeker optical system, and gives its layout diagram, as shown in Figure 2 .

[0042] The specific off-axis field of view parameters set in the embodiment are ωx = 0°, ωy = 26°, and a specific wavelength λ = 633 nm. The wavefront aberration distribution in the exit pupil plane is obtained by using the wavefront aberration acquisition method of the optical system according to the present application, as shown in FIG. 6. Figure 3

[0043] Figure 3 In the figure, the horizontal and vertical coordinates are normalized pupil coordinates, and the value range thereof is [-1, 1], which represents the two-dimensional coordinates of the normalized pupil aperture range. In the coordinate system, the geometric boundaries of the pupil (including the entrance pupil and the exit pupil) are normalized into a unit circle, which facilitates comparative analysis between different systems. The numerical value corresponding to the color bar represents the wavefront aberration value (in wavelength unit) at each position point in the exit pupil plane. As can be seen from Figure 3 , due to the large angle of the off-axis field of view relative to the optical axis, the exit pupil is obviously deformed from an ideal circle into an ellipse.

[0044] The specific on-axis field of view parameters set in the embodiment are ωx = 0°, ωy = 0°, and a specific wavelength λ = 633 nm. The wavefront aberration distribution in the exit pupil plane is obtained by using the wavefront aberration acquisition method of the optical system according to the present application, as shown in FIG. 8. Figure 4

[0045] Figure 4 The definitions of the horizontal and vertical coordinates and the meaning of the color bar are consistent with those in Figure 3 . As can be seen from Figure 4 , since the on-axis field of view satisfies the mathematical relationship TFNO = SFNO, the exit pupil presents a perfect circle.

[0046] The above only describes the preferred embodiments of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.​​

Claims

1. A method for obtaining wavefront aberration of an optical system based on generalized pupil function, characterized in that, The method comprises the following steps: Step one: obtain the incident wavelength λ and the field of view angle (θ) of the optical system to be detected ω x , ω y ) Step two: obtain the entrance pupil and exit pupil parameters, according to the structure parameters of the optical system and the position of the aperture stop, determine the entrance pupil position ENPP and the entrance pupil diameter ENPD by using the paraxial ray tracing algorithm; further determine the corresponding exit pupil position EXPP, the exit pupil position EXPP refers to the exit pupil relative to the image plane z displacement; Step three: determine the meridional working F-number TFNO and sagittal F-number SFNO at the wavelength λ and field angle (θ, φ) ω x , ω y ) Step four: according to the TFNO and SFNO, a normalized transmission aperture is solved, and then a normalized pupil plane is obtained; Step five: uniformly sampling in the normalized pupil plane to obtain sampling points, and generating an incident ray array according to the ENPD, ENPP and field of view angle (θx, θy) ω x , ω y ) Step six: according to an actual ray tracing algorithm, the incident light array is traced to an image plane; Step seven: virtual reference spherical surface parameters are determined; Step eight: optical system wave aberration is obtained.

2. The optical system wave aberration acquisition method according to claim 1, wherein The method for determining the meridional direction working F number TFNO and the sagittal direction F number SFNO in step three comprises: Step S3.1: obtaining three direction vectors in the meridional plane of the optical system to be detected according to an actual ray tracing algorithm, under the wavelength λ and the field angle (θ, φ) ω x , ω y ) of the optical system to be detected, the unit direction vector of the upper edge ray propagating to the image plane , the unit direction vector of the lower edge ray propagating to the image plane , and the unit direction vector of the chief ray propagating to the image plane ; Step S3.2: Obtain two angles in the tangential plane using the three direction vectors obtained in step S3.1 : the angle of the upper edge ray relative to the chief ray θ T,UP , and the angle of the lower edge ray relative to the chief ray θ T,DOWN ; Step S3.3: according to (1) Obtaining the meridional working F-number TFNO, where n n is the image-side refractive index; Step S3.4: according to the method in steps S3.1 to S3.3, the left and right edge rays in the sagittal plane are traced, the included angles of the left and right edge rays with respect to the chief ray are calculated, and the sagittal direction F number SFNO is obtained according to the two included angles.

3. The optical system wave aberration acquisition method according to claim 1, wherein The process for obtaining the normalized transmission aperture in step four is as follows: Step S4.1: determining a normalized aperture boundary equation at the wavelength λ and field angle (θ, φ) based on the TFNO and SFNO: ω x , ω y ) (2) In the formula P x , P y is the normalized pupil plane coordinate of the optical system, whose domain is in the interval [-1, 1]; the aperture boundary is determined according to the above equation; Step S4.2: a normalized pupil coordinate plane is created, and the region within the aperture boundary determined in step S4.1 is a transmission aperture region, which is an effective pupil range of the optical system under an on-axis or off-axis field of view, and the pupil refers to an entrance pupil and an exit pupil.

4. The optical system wave aberration acquisition method according to claim 1, wherein The method for generating the incident light array in step five comprises: Step S5.1: in the normalized pupil plane, a series of sampling points are obtained by uniform sampling at a set resolution; Step S5.2: determining the starting point of each incident light ray in the global coordinate system according to the series of sampling points and the entrance pupil diameter ENPD, the entrance pupil position ENPP, according to the field of view angle (θ, φ) of the optical system, and the entrance pupil position ENPP. ω x , ω y ), in accordance with (3) A unit direction vector of each incident light is obtained, and all the incident lights form an incident light array.

5. The optical system wave aberration acquisition method of claim 1, wherein, The process for tracing the incident light array to the image plane according to the actual ray tracing algorithm in step six comprises: Step S6.1: the incident light array generated in step five is input into an optical system model; Step S6.2: the propagation path of each light in the incident light array through the optical system is calculated by an actual ray tracing algorithm; Step S6.3: According to the obtained all propagation paths, the intersection position of each light ray on the image plane, the unit direction vector and its actual optical path information are obtained, and the actual optical path of all light rays constitutes a matrix OPTH MT ; Step S6.4: According to steps S6.1 to S6.3, the intersection position of the chief ray on the image plane, the unit directional vector and its actual optical path information of the chief ray are solved by using the actual ray tracing algorithm, and the actual optical path of the chief ray is OPTH CR .

6. The optical system wave aberration acquisition method of claim 1, wherein, The virtual reference spherical surface parameters in step seven are obtained by solving a reference spherical surface equation: (4) Step eight: the specific method for obtaining the optical system wave aberration is as follows: In the equation, x CR , y CR , z CR are the coordinates of the chief ray in the global coordinate system in the image plane; R the radius of the virtual reference sphere is given by: (5) In the equation is the unit directional vector of the chief ray at the image plane z to the projection component.

7. The optical system wave aberration acquisition method of claim 1, wherein, Step S8.1: a ray equation is established; According to the actual ray tracing result, the straight line equation of any light in the incident light array in a global coordinate system is as follows: Step S8.3: the optical path of the chief ray from the image plane to the reference spherical surface is solved; (6) denotes the optical path, x real , y real , z real is the image plane in global coordinate system of each array ray in the incident light ray array, k x,real , k y,real , k z,real is the projection of the unit direction vector of the array ray in the image plane in x , y , z three directions; Step S8.2: obtaining the optical path of each array light ray from the image plane to the reference sphere according to the straight line equation and the reference sphere equation t ; For the case that the exit pupil center does not coincide with the image plane, the inner product between the direction vector of the array light and the radius vector from the Gaussian image point to the exit pupil center is calculated. If the inner product result is positive, the solution of t>0 is taken, otherwise the solution of t<0 is taken. The matrix composed of the optical paths of all array lights from the image plane to the reference sphere is denoted as T . Step S8.4: a two-dimensional distribution of wave aberration in a paraxial exit pupil plane is solved: According to the main light ray tracing result, the main light ray optical path from the image surface to the reference sphere is solved t CR ; A two-dimensional distribution of wave aberration in the paraxial exit pupil plane is obtained. (7) ​

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