Image quality analysis method and device based on frustum geometric constraints and negative feedback control

Abstract

The present invention provides an image quality analysis method and device based on frustum geometric constraints and negative feedback control. The method comprises: step S1: obtaining vertical chromatic aberration, axial chromatic aberration, and wave chromatic aberration of a multi-conjugate catadioptric zoom system; step S2: solving the wave aberration of the multi-conjugate catadioptric zoom system after wavelength modulation; step S3: determining the position of the characteristic aberration node based on the wave aberration and calculating the RMS spot diameter near the central field of view; step S4: using frustum geometric constraints, in a manner that corrects vertical chromatic aberration and axial chromatic aberration, taking the material Abbe number as a variable, performing negative feedback control on the position of the characteristic aberration node to suppress the influence of chromatic aberration, and comprehensively analyzing the imaging quality of the multi-conjugate catadioptric zoom system. The present invention is suitable for comprehensive image quality analysis of multi-conjugate catadioptric zoom systems, and has broad application prospects, particularly in catadioptric zoom optical systems that achieve high-performance zoom functions and wide-spectrum imaging through deformable devices.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic imaging technology, and in particular to an image quality analysis method and device based on frustum geometric constraints and negative feedback control. Background Art

[0002] In recent years, off-axis optical systems containing refractive elements have been widely studied. These systems, which combine refractive and reflective optical elements, are considered catadioptric optical systems. Compared with purely off-axis reflective systems, chromatic aberrations occur, further increasing the complexity of aberrations. To achieve an unobstructed system structure, the reflective elements need to be configured with appropriate decentration or tilt parameters. However, this introduces off-axis aberrations, causing the characteristic aberration nodes to shift away from the center of the field of view. This phenomenon can be analyzed using nodal aberration theory. However, nodal aberration theory only applies to a single wavelength and is not applicable to catadioptric systems over a wide spectral range where chromatic aberrations exist. The chromatic aberration effects produced by refractive elements cause the characteristic aberration nodes to shift differently at different wavelengths. When correcting for off-axis aberrations, if the characteristic aberration nodes cannot converge within a specific range across the entire wavelength band, the system's imaging quality will be significantly degraded.

[0003] Catadioptric zoom systems need to achieve high-quality imaging across the entire focal range and wavelength range. Analyzing and controlling the characteristic aberration nodes of multi-conjugate systems is crucial. Therefore, an image quality analysis method for evaluating catadioptric optical systems is crucial to guide the control of the characteristic aberration nodes of multi-conjugate catadioptric zoom systems. Summary of the Invention

[0004] In view of this, the present invention provides an image quality analysis method and apparatus based on frustum geometric constraints and negative feedback control to solve at least one of the above-mentioned problems.

[0005] In order to achieve the above object, the present invention adopts the following scheme:

[0006] According to a first aspect of the present invention, there is provided an image quality analysis method based on frustum geometric constraints and negative feedback control, the method comprising:

[0007] Step S1: Obtaining vertical chromatic aberration, axial chromatic aberration, and wave chromatic aberration of a multi-conjugate catadioptric zoom system;

[0008] Step S2: solving the wavefront aberration of the multi-conjugation catadioptric zoom system after wavelength modulation under the condition of multi-conjugation of focal length and wavelength;

[0009] Step S3: determining the characteristic aberration node position of the multi-conjugate catadioptric zoom system according to the wavefront aberration and calculating the RMS spot diameter within the set range of the central field of view;

[0010] Step S4: Using the frustum geometric constraint, the vertical axis chromatic aberration and the axial chromatic aberration correction method, and the material Abbe number as a variable, the position of the characteristic aberration node is negatively feedback controlled to suppress the influence of chromatic aberration, and the imaging quality of the multi-conjugate catadioptric zoom system within the full focal length and full band is comprehensively analyzed.

[0011] As an embodiment of the present invention, the above step S2 further includes:

[0012] Step S21: sampling focal length intervals in the multi-conjugate catadioptric zoom system, setting a spectral range, and selecting spectral lines;

[0013] Step S22: solving the wavefront aberration of the catadioptric zoom system after wavelength modulation under the condition of multiple conjugation of focal length and wavelength;

[0014] Step S23: Repeat the above steps S21-S22 at all sampling focal lengths in the full focal range to obtain the output wavefront aberration values ​​of the multi-conjugate catadioptric zoom system at multiple conjugate positions within the full focal range and full wavelength range.

[0015] As an embodiment of the present invention, the above step S22 further includes:

[0016] Step S221: Using wavefront aberration as a basis for evaluating and correcting errors in light propagating through the optical system, the complex wavefront at the lens exit is decomposed into wavefront aberrations of different types of bases;

[0017] Step S222: calculating the coefficient value of the wavefront aberration of the multi-conjugate catadioptric zoom system at the focal length for different sampling wavelengths;

[0018] Step S223: Calculating the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal length positions is completed using the deformable device.

[0019] As an embodiment of the present invention, the above step S3 further includes:

[0020] Step S31: sampling the field of view within the full field of view, calculating the vector aberration of various aberration items under all sampled fields of view, and obtaining an aberration full field of view map;

[0021] Step S32: determining whether the system has a characteristic aberration node according to the aberration full field of view map, and calculating the position of the characteristic aberration node;

[0022] Step S33: Calculate the RMS spot diameter within the set range of the central field of view.

[0023] As an embodiment of the present invention, the above step S4 further includes:

[0024] Step S41: establishing frustum geometric constraints;

[0025] Step S42: determining whether the characteristic aberration node position within the full focal length and full wavelength range is included in the geometric constraints, and performing negative feedback control on the characteristic aberration node position by using the vertical axis chromatic aberration and the axial axis chromatic aberration correction method and the material Abbe number as a variable;

[0026] Step S43: Calculate the variance value from the characteristic aberration node position to its centroid within the full band range at all sampling focal lengths, and the RMS spot diameter root mean square value of each sampling field within the frustum geometric constraint range as system image quality evaluation indicators.

[0027] According to a second aspect of the present invention, there is provided an image quality analysis device based on frustum geometric constraints and negative feedback control, the device comprising:

[0028] A chromatic aberration acquisition unit, used for acquiring vertical axis chromatic aberration, axial chromatic aberration and wave chromatic aberration of the multi-conjugate catadioptric zoom system;

[0029] a wavefront aberration solving unit, configured to solve the wavefront aberration of the multi-conjugated catadioptric zoom system after wavelength modulation under the condition of multi-conjugated focal length and wavelength;

[0030] a position and spot determination unit, configured to determine the characteristic aberration node position of the multi-conjugate catadioptric zoom system according to the wave aberration and calculate the RMS spot diameter within a set range of the central field of view;

[0031] A control and analysis unit is used to use the frustum geometric constraint, the vertical axis chromatic aberration and the axial chromatic aberration correction method, and the material Abbe number as a variable to negatively feedback control the position of the characteristic aberration node to suppress the influence of chromatic aberration, and comprehensively analyze the imaging quality of the multi-conjugate catadioptric zoom system within the full focal length and full band range.

[0032] As an embodiment of the present invention, the wave aberration solving unit includes:

[0033] a sampling setting module, for sampling focal length intervals in the multi-conjugate catadioptric zoom system, and setting spectral ranges and selecting spectral lines;

[0034] A solution module for solving the wavefront aberration of a catadioptric zoom system under the conditions of multiple conjugation of focal length and wavelength after wavelength modulation;

[0035] The sampling setting module and the solving module are executed in sequence until the output wave aberration value of the multi-conjugate catadioptric zoom system at the multi-conjugate position within the full focal length and full wavelength range is obtained.

[0036] As an embodiment of the present invention, the above-mentioned solution module includes:

[0037] A disassembly submodule is used to use wavefront aberration as a basis for evaluating and correcting errors caused by light propagating through the optical system, and to disassemble the complex wavefront at the lens exit into wavefront aberrations of different types of bases;

[0038] A first calculation submodule is configured to calculate, for different sampling wavelengths, coefficient values ​​of wavefront aberration of the multi-conjugate catadioptric zoom system at the focal length;

[0039] The second calculation submodule is used to calculate the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal length positions is completed using the deformable device.

[0040] As an embodiment of the present invention, the position and light spot determination unit includes:

[0041] The field of view map acquisition module is used to sample the field of view within the full field of view, calculate the vector aberration of various aberration items under all sampled fields of view, and obtain the full field of view aberration map;

[0042] A node calculation module is used to determine whether there is a characteristic aberration node in the system according to the aberration full field of view map, and calculate the position of the characteristic aberration node;

[0043] The RMS spot calculation module is used to calculate the RMS spot diameter within the set range of the central field of view.

[0044] As an embodiment of the present invention, the control analysis unit includes:

[0045] Frustum constraint establishment unit, used to establish frustum geometric constraints;

[0046] a feedback control module, configured to determine whether the characteristic aberration node position within the full focal length and full wavelength range is contained within the geometric constraints, and to perform negative feedback control on the characteristic aberration node position using the vertical axis chromatic aberration and the axial axis chromatic aberration correction method and the material Abbe number as a variable;

[0047] The image quality analysis module is used to calculate the variance value from the characteristic aberration node position to its center of mass within the full band range at all sampling focal lengths, and the RMS spot diameter root mean square value of each sampling field within the frustum geometric constraint range, as the system image quality evaluation index.

[0048] According to a third aspect of the present invention, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0049] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0050] As can be seen from the above technical solution, the image quality analysis method and device based on frustum geometric constraints and negative feedback control provided by the present invention utilizes the nodal aberration characteristics of a catadioptric system across the entire focal length and wavelength range to analyze the impact of chromatic aberration on the system's image quality. Using frustum geometric constraints, negative feedback control is performed on the locations of the characteristic aberration nodes, guiding the optimization direction of the catadioptric system and improving the system's imaging quality. This method is suitable for comprehensive image quality analysis of multi-conjugate catadioptric zoom systems, and has broad application prospects, particularly in catadioptric zoom optical systems that achieve high-performance zoom functions and wide-spectrum imaging through deformable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0052] Figure 1 This is a flow chart of an image quality analysis method based on frustum geometric constraints and negative feedback control provided in an embodiment of the present application;

[0053] Figure 2 This is a two-dimensional structural diagram of a multi-conjugate catadioptric zoom system provided in an embodiment of the present application;

[0054] Figure 3 1 is a schematic diagram of a process for solving wave aberration provided in an embodiment of the present application;

[0055] Figure 4 This is a schematic diagram of a specific process for solving wave aberrations provided in an embodiment of the present application;

[0056] Figure 5 1 is a flow chart of determining the position of characteristic aberration nodes and calculating the RMS spot diameter provided in an embodiment of the present application;

[0057] Figure 6 This is a schematic diagram of a comprehensive analysis process using frustum geometric constraints and negative feedback control provided in an embodiment of the present application;

[0058] Figure 7 This is a full-field-of-view image of aberration provided in an embodiment of the present application;

[0059] Figure 8 Schematic diagram of the RMS spot diameter of the system in all focal lengths and all wavelengths under the frustum geometric constraints provided in an embodiment of the present application;

[0060] Figure 9Schematic diagram of the structure of an image quality analysis device based on frustum geometric constraints and negative feedback control provided in an embodiment of the present application;

[0061] Figure 10 Schematic diagram of the structure of the wave aberration solving unit provided in an embodiment of the present application;

[0062] Figure 11 It is a schematic diagram of the structure of the solution module provided in the embodiment of the present application;

[0063] Figure 12 Schematic diagram of the structure of the position and light spot determination unit provided in an embodiment of the present application;

[0064] Figure 13 Schematic diagram of the structure of the control and analysis unit provided in the embodiment of the present application;

[0065] Figure 14 This is a schematic block diagram of the system structure of the electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0066] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0067] like Figure 1 FIG. 1 is a flow chart of an image quality analysis method based on frustum geometric constraints and negative feedback control provided in an embodiment of the present application. The method includes the following steps:

[0068] Step S1: Obtaining the vertical chromatic aberration, axial chromatic aberration, and wave chromatic aberration of the multi-conjugate catadioptric zoom system.

[0069] The two-dimensional structure of the multi-conjugate catadioptric zoom system of this embodiment is as follows: Figure 2 As shown, the system consists of four components: a front fixed group, a zoom group, a compensation group, and a rear fixed group. All components except the zoom group use refractive elements, introducing chromatic aberration into the system. The zoom group is designed as a three-mirror structure, with the first and third reflective elements' surface shapes achieved using deformable devices to meet zoom and image quality correction requirements. The following explains how to analyze the impact of chromatic aberration on a catadioptric zoom system and calculate vertical and axial chromatic aberration:

[0070] When light propagates in a medium, different wavelengths of light propagate at different speeds, causing the refractive index of the lens to behave differently for different wavelengths of light. This dispersion effect causes light of different wavelengths to focus at different positions after passing through the refractive system. This dispersion effect is divided into two types: axial chromatic aberration coefficient and vertical chromatic aberration coefficient. These can be calculated using the following equations (1) and (2) after ray tracing:

[0071] Axial chromatic aberration:

[0072] Vertical axis chromatic aberration:

[0073] In the above formula, dn and dn' are the dispersion of the medium on both sides of the refractive surface, and n and n' are the refractive indices of the intermediate colors on both sides of the refractive surface. Therefore, both axial chromatic aberration and vertical chromatic aberration are functions of Abbe's constant, that is,

[0074] In this embodiment, the catadioptric zoom system is designed as a visual optical system, and the system wavelength range is selected as visible light. The wave chromatic aberration calculation formula is the following formula (3):

[0075]

[0076] Wave chromatic aberration causes the wave aberration of the catadioptric zoom system to be modulated by wavelength. This modulation changes with the Abbe constant, so ν is chosen as a variable to control the aberration.

[0077] Step S2: solving the wavefront aberration of the multi-conjugation catadioptric zoom system after wavelength modulation under the condition of multi-conjugation of focal length and wavelength.

[0078] Preferably, Figure 3 As shown, this step S2 may further include the following sub-steps:

[0079] Step S21: sampling the focal length interval in the multi-conjugate catadioptric zoom system, setting the spectral range and selecting the spectral line.

[0080] After determining the aberration characteristics of the catadioptric zoom system, including chromatic aberration introduced by refraction and off-axis aberration introduced by reflection, the catadioptric zoom system is sampled at a certain zoom sensitivity interval within the full focal length range, and the spectral range is set and the spectral lines are selected.

[0081] In this embodiment, the zoom sensitivity is δf=(f T -f W ) / (N-1), where f T and f W Represent the focal length of the wide-angle end and telephoto end system respectively, N is the number of sampling points, and δf is the minimum zoom interval that the system can achieve. The sampling wavelength is λ c =656.27mm,λ d =587.56mm,λ F =486.13mm, corresponding to the two ends of the human eye's sensitive spectral range and the most sensitive spectral line.

[0082] Step S22: solving the wavefront aberration of the catadioptric zoom system after wavelength modulation under the condition of multiple conjugation of focal length and wavelength.

[0083] After completing the free-form surface design at all focal lengths using a deformable device, a sampling wavelength is selected for any sampling focal length of the catadioptric system, and the wavefront aberration at each wavelength is calculated.

[0084] In this embodiment, if Figure 4 As shown, this step may further include the following sub-steps:

[0085] Step S221: Using wavefront aberration as a basis for evaluating and correcting errors caused by light propagating through the optical system, the complex wavefront at the lens exit is decomposed into wavefront aberrations of different types of bases.

[0086] Step S222: Calculating the coefficient value of the wavefront aberration of the multi-conjugate catadioptric zoom system at the focal length for different sampling wavelengths.

[0087] Step S223: Calculating the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal length positions is completed using the deformable device.

[0088] The above steps S221-S223 are described in detail below:

[0089] In this embodiment, wavefront aberration is used as a basis for evaluating and correcting errors caused by light propagating through an optical system. The complex wavefront at the exit pupil is decomposed into wavefront aberrations of different types. The specific implementation process is as follows: when using fourth-order wavefront aberration to describe the system wavefront at the exit pupil, the basis functions in the wavefront aberration expression are primary spherical aberration, primary coma, primary astigmatism, primary field curvature, and primary distortion.

[0090] In this embodiment, the wavefront aberration coefficient values ​​of the catadioptric system at the focal length are calculated for different sampling wavelengths. The specific implementation process is as follows: the magnitude of the fourth-order wavefront aberration coefficient reflects the contribution of each coefficient to the wavefront aberration type, and is obtained by tracing the marginal rays of the on-axis field of view and the principal rays of the marginal field of view. The calculation complies with the strict law of refraction. In the absence of component eccentricity or tilt, and without considering the influence of aspheric surfaces, the fourth-order wavefront aberration coefficient of the catadioptric system at the focal length is calculated for different sampling wavelengths, and is obtained by the following equations (4)-(8):

[0091] Primary spherical aberration:

[0092] Primary coma:

[0093] Primary astigmatism:

[0094] Primary Field Song:

[0095] Primary distortion:

[0096] In the above formula, j is the surface number, n and n' are the medium refractive index, u and u' are the edge ray angles, is the main ray angle, h is the edge ray height, is the main ray height, c is the surface curvature, λ is the sampling wavelength, A. Parameters such as h are all functions of the refractive index n, which is affected by wavelength. That is, the wavefront aberration of the system at the optical output will be modulated by wavelength changes.

[0097] In this embodiment, the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal lengths is completed using a deformable device is calculated. The specific implementation process is as follows: The wavefront aberration at the focal length can be expressed as the following formula (9):

[0098]

[0099] In the above formula They represent the primary spherical aberration, coma, astigmatism, field curvature, and distortion aberration of the deformable device at wavelength λ before adding the free-form surface term. In this embodiment, only the aberration correction of spherical aberration, coma, and astigmatism is discussed. In order to achieve an unobstructed system structure, an eccentric element is introduced into the reflective element. According to the different distribution characteristics of the aberration field with respect to the field of view and aperture, the vector aberration expression of the primary aberration is formed as follows (10)-(12):

[0100] Primary spherical aberration:

[0101] Primary coma:

[0102] Primary astigmatism:

[0103] Where, is the pore diameter, is the field of view vector, is the aberration eccentricity vector,

[0104] In this embodiment, a deformation device is used to superimpose the Fringe Zernike polynomial surface shape, using Z 5 / 6 、Z 7 / 8 After completing the design of the free-form surface primary spherical aberration, primary coma, and primary astigmatism, the wavefront aberration of the system at different sampling wavelengths is calculated as follows (13)-(15):

[0105] Primary spherical aberration:

[0106] Primary coma:

[0107] Primary astigmatism:

[0108] In the above formula, They represent the spherical aberration, coma, and astigmatism caused by the deformation device superimposed on the Fringe Zernike surface shape, M n =-2n / λZ n , Z 5 / 6 、Z 7 / 8 , Z9 is the marginal Zernike coefficient obtained by superimposing different Fringe Zernike terms.

[0109] Step S23: Repeat the above steps S21-S22 at all sampling focal lengths in the full focal range to obtain the output wavefront aberration values ​​of the multi-conjugate catadioptric zoom system at multiple conjugate positions within the full focal range and full wavelength range.

[0110] Repeat the above steps S21-S22 at all sampling focal lengths in the full focal range to obtain a set of output wave aberration values ​​of the catadioptric zoom system at multiple conjugate positions in the full focal range and full wavelength range. where λ k ∈{λ c ,λ d ,λ F} is the sampling light wavelength, f i =f W +(i-1)δf,1<i<N is the sampling focal length.

[0111] Step S3: determining the characteristic aberration node position of the multi-conjugate catadioptric zoom system according to the wavefront aberration and calculating the RMS spot diameter within the set range of the central field of view.

[0112] Preferably, Figure 5 As shown, this step S3 may further include the following sub-steps:

[0113] Step S31: sampling the field of view within the full field of view, calculating the vector aberration of various aberration items in all sampled fields of view, and obtaining an aberration full field of view map.

[0114] This embodiment uniformly samples the field of view within the entire field of view, calculates the aberration magnitude and direction of various aberrations in the entire sampled field of view at each wavelength for any sampling focal length, and draws an aberration field diagram.

[0115] Step S32: determining whether the system has a characteristic aberration node based on the aberration full field of view map, and calculating the position of the characteristic aberration node.

[0116] In this embodiment, the node is defined as the point where the aberration term value is 0 in the full field of view. The full field of view diagram with an aberration node has the characteristic that the vector aberration is in a "flowing" state in the full field of view and converges to the node. Let the wave aberration value of a specific aberration term at the lens exit be equal to 0. The field of view coordinates that meet the above conditions are the characteristic aberration node coordinates. The characteristic aberration node positions of coma and astigmatism at any focal length and any wavelength Calculate and solve the following equations (16) and (17):

[0117]

[0118]

[0119] By repeating the above steps at all sampling focal lengths and all sampling wavelengths, a set of coma and astigmatism node positions of the multi-conjugate catadioptric zoom system within the full focal length and full wavelength range can be obtained.

[0120] Step S33: Calculate the RMS spot diameter within the set range of the central field of view.

[0121] Calculate the central field of view of all fields of view within the full band at any focal length The RMS spot diameter in the vicinity is used to measure the impact of wavefront distortion caused by chromatic aberration on imaging quality. R i Indicates that the system is at the sampling focal length f i The coordinate constraint radius of the sampling field of view in the x and y directions is further repeated at all sampling focal lengths and all sampling wavelengths to obtain the RMS spot diameter near the center field of view of the multi-conjugate catadioptric zoom system within the full focal length and full band range.

[0122] Step S4: Using the frustum geometric constraint, the vertical axis chromatic aberration and the axial chromatic aberration correction method, and the material Abbe number as a variable, the position of the characteristic aberration node is negatively feedback controlled to suppress the influence of chromatic aberration, and the imaging quality of the multi-conjugate catadioptric zoom system within the full focal length and full band is comprehensively analyzed.

[0123] Preferably, Figure 6 As shown, this step S4 may further include the following sub-steps:

[0124] Step S41: Establishing frustum geometric constraints.

[0125] The frustum geometric constraint reflects the characteristic aberration node control target, and the constrained geometric space is expressed by the following formula (18):

[0126]

[0127] Where, R i Indicates that the system is at the sampling focal length f i The x and y direction sampling field coordinate constraint radius, R1 and R N represent the upper base radius and the lower base radius respectively.

[0128] Step S42: determining whether the characteristic aberration node position within the full focal length and full wavelength range is contained within the geometric constraints, and using the vertical axis chromatic aberration and the axial chromatic aberration correction method, taking the material Abbe number as a variable, and performing negative feedback control on the characteristic aberration node position.

[0129] Determine the position of characteristic aberration nodes within the full focal length and full band Is it included in the geometric constraints? If not, it is necessary to continue to optimize the design system structure and use the Abbe number as a variable to adjust the node position to within the constraints. Figure 7 Given the three zoom positions of wide angle end, middle focal length and telephoto end respectively, the multi-conjugate catadioptric zoom system is c =656.27mm,λ d =587.56mm,λ F =486.13mm at three sampling wavelengths, and the locations of the characteristic aberration nodes are marked. The multi-conjugate catadioptric zoom system is realized by using the method of frustum geometry to constrain chromatic aberration and negative feedback to control the characteristic nodes. The characteristic aberration nodes can be constrained within a frustum geometry within the full focal length and full band.

[0130] Step S43: Calculate the variance value from the characteristic aberration node position to its centroid within the full band range at all sampling focal lengths, and the RMS spot diameter root mean square value of each sampling field within the frustum geometric constraint range as system image quality evaluation indicators.

[0131] The centroid of the characteristic aberration node positions and the variance of each node to the centroid are calculated across the entire band at all sampling focal lengths to measure the degree of node position dispersion. The RMS spot diameter of each sampling field of view within the geometric constraints of the frustum is calculated to measure the overall size of the spot near the center of the field of view. These two indicators are used to evaluate the image quality of the multi-conjugate catadioptric system. Figure 8 The RMS spot diameter of the system in the full focal length and full wavelength band under the frustum geometric constraints set by this method is given.

[0132] From the above, it can be seen that the present invention targets the chromatic aberration and off-axis aberration characteristics of a multi-conjugate catadioptric zoom system. By calculating the system exit pupil wave aberration at different wavelengths, the characteristic aberration node positions within the full focal length and full wavelength range are obtained, and the distance between the nodes is calculated. At the same time, the RMS spot diameter is combined as an image quality analysis method for evaluating the catadioptric zoom system at multiple conjugate focal lengths and wavelengths. By establishing a frustum geometric constraint, the optimization direction of the system chromatic aberration and off-axis aberration is guided, breaking the limitation of the nodal aberration theory that is only applicable to a single wavelength, and establishing an image quality analysis method for a multi-conjugate catadioptric zoom system.

[0133] The image quality analysis method based on frustum geometric constraints and negative feedback control provided by this embodiment has the following advantages: it can comprehensively analyze the imaging quality of the catadioptric zoom system in the full focal length and full band range, especially under the combined influence of chromatic aberration and off-axis aberration. By calculating the aberration field diagram under multiple conjugate positions to analyze whether the system aberration converges, the characteristic aberration node position is controlled in a negative feedback manner in combination with the frustum geometric constraints, and the node position distance and RMS spot diameter mean square error index are combined to evaluate the system's comprehensive image quality, guide the system optimization direction, and effectively improve the system's design accuracy and imaging performance. This method is suitable for achieving high-performance zoom and wide-spectrum high-quality imaging, especially in multiple conjugate catadioptric zoom systems with complex aberration performance, and has significant application advantages.

[0134] like Figure 9 The figure shows a schematic diagram of the structure of an image quality analysis device based on truncated cone geometric constraints and negative feedback control provided by an embodiment of the present application. The device includes: a chromatic aberration acquisition unit 910, a wavefront aberration solving unit 920, a position and spot determination unit 930, and a control and analysis unit 940, which are sequentially connected. Among them:

[0135] The chromatic aberration obtaining unit 910 is used to obtain the vertical chromatic aberration, the axial chromatic aberration and the wave chromatic aberration of the multi-conjugate catadioptric zoom system.

[0136] The wavefront aberration solving unit 920 is used to solve the wavefront aberration of the multi-conjugation catadioptric zoom system after wavelength modulation under the condition of multi-conjugation of focal length and wavelength.

[0137] The position and spot determination unit 930 is used to determine the characteristic aberration node position of the multi-conjugate catadioptric zoom system according to the wave aberration and calculate the RMS spot diameter within the set range of the central field of view.

[0138] The control and analysis unit 940 is used to use the frustum geometric constraints, the vertical axis chromatic aberration and the axial chromatic aberration correction method, and the material Abbe number as a variable to negatively feedback control the position of the characteristic aberration node to suppress the influence of chromatic aberration, and comprehensively analyze the imaging quality of the multi-conjugate catadioptric zoom system within the full focal length and full band range.

[0139] Preferably, Figure 10 As shown, the wave aberration solving unit 920 includes:

[0140] The sampling setting module 921 is used to sample the focal length interval in the multi-conjugate catadioptric zoom system, set the spectral range and select the spectral line.

[0141] The solving module 922 is used to solve the wavefront aberration of the catadioptric zoom system after wavelength modulation under the condition of multiple conjugation of focal length and wavelength.

[0142] The sampling setting module 921 and the solving module 922 are executed in sequence until the output wave aberration value of the multi-conjugate catadioptric zoom system at the multi-conjugate position within the full focal length and full wavelength range is obtained.

[0143] Preferably, Figure 11 As shown, the above-mentioned solution module 922 further includes:

[0144] The disassembly submodule 9221 is used to use wavefront aberration as a basis for evaluating and correcting errors caused by light propagating through the optical system, and to disassemble the complex wavefront at the lens into wavefront aberrations of different types of bases.

[0145] The first calculation submodule 9222 is configured to calculate the coefficient value of the wavefront aberration of the multi-conjugate catadioptric zoom system at the focal length for different sampling wavelengths.

[0146] The second calculation submodule 9223 is used to calculate the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal length positions is completed using the deformable device.

[0147] Preferably, Figure 12 As shown, the position and light spot determination unit 930 includes:

[0148] The field of view map acquisition module 931 is used to sample the field of view within the full field of view, calculate the vector aberration of various aberration items under all sampled fields of view, and obtain the full field of view aberration map.

[0149] The node calculation module 932 is used to determine whether there is a characteristic aberration node in the system according to the aberration full field of view map, and calculate the position of the characteristic aberration node.

[0150] The RMS spot calculation module 933 is used to calculate the RMS spot diameter within the set range of the central field of view.

[0151] Preferably, Figure 13 As shown, the control analysis unit 940 includes:

[0152] The frustum constraint establishing unit 941 is used to establish frustum geometric constraints.

[0153] The feedback control module 942 is used to determine whether the characteristic aberration node position within the full focal length and full band is contained in the geometric constraints, and to perform negative feedback control on the characteristic aberration node position using the vertical axis chromatic aberration and the axial axis chromatic aberration correction method and the material Abbe number as a variable.

[0154] The image quality analysis module 943 is used to calculate the variance value from the characteristic aberration node position to its center of mass within the full band range at all sampling focal lengths, and the RMS spot diameter root mean square value of each sampling field within the frustum geometric constraint range as system image quality evaluation indicators.

[0155] The detailed description of the above-mentioned units and modules can be found in the corresponding description in the aforementioned method embodiment, which will not be repeated here.

[0156] From the above, it can be seen that the image quality analysis device based on frustum geometric constraints and negative feedback control provided by this embodiment has the following advantages: it can comprehensively analyze the imaging quality of the catadioptric zoom system in the full focal length and full band range, especially under the combined influence of chromatic aberration and off-axis aberration. By calculating the aberration field diagram under multiple conjugate positions to analyze whether the system aberration converges, the characteristic aberration node position is controlled in a negative feedback manner in combination with the frustum geometric constraints, and the node position distance and RMS spot diameter mean square error index are combined to evaluate the system's comprehensive image quality, guide the system optimization direction, and effectively improve the system's design accuracy and imaging performance. This method is suitable for achieving high-performance zoom and wide-spectrum high-quality imaging, especially in multiple conjugate catadioptric zoom systems with complex aberration performances, and has significant application advantages.

[0157] An embodiment of the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the above method is implemented when the processor executes the program.

[0158] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program for executing the above method.

[0159] like Figure 14As shown, the electronic device 600 may further include: a communication module 110, an input unit 120, an audio processor 130, a display 160, and a power supply 170. It is worth noting that the electronic device 600 does not necessarily have to include Figure 14 In addition, the electronic device 600 may also include all components shown in Figure 14 For components not shown, reference may be made to the prior art.

[0160] like Figure 14 As shown, the central processing unit 100 is sometimes also referred to as a controller or an operation control unit, and may include a microprocessor or other processor device and / or logic device. The central processing unit 100 receives inputs and controls the operations of various components of the electronic device 600 .

[0161] Memory 140 may be, for example, one or more of a cache, flash memory, hard drive, removable media, volatile memory, non-volatile memory, or other suitable devices. It may store the aforementioned failure-related information and may also store programs that execute the relevant information. The CPU 100 may execute the programs stored in memory 140 to implement information storage or processing.

[0162] The input unit 120 provides input to the CPU 100. The input unit 120 may be, for example, a keypad or touch input device. The power supply 170 is used to provide power to the electronic device 600. The display 160 is used to display objects such as images and text. The display may be, for example, an LCD display, but is not limited thereto.

[0163] The memory 140 may be a solid-state memory, such as a read-only memory (ROM), a random access memory (RAM), or a SIM card. Alternatively, it may be a memory that retains information even when power is off, can be selectively erased, and is provided with more data. Examples of such memory are sometimes referred to as EPROMs. The memory 140 may also be some other type of device. The memory 140 includes a buffer memory 141 (sometimes referred to as a buffer). The memory 140 may include an application / function storage unit 142 for storing application programs and function programs or processes for executing the operations of the electronic device 600 via the central processing unit 100.

[0164] The memory 140 may also include a data storage unit 143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 144 of the memory 140 may include various driver programs for communication functions of the electronic device and / or for executing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0165] The communication module 110 is a transmitter / receiver that transmits and receives signals via the antenna 111. The communication module 110 (transmitter / receiver) is coupled to the central processor 100 to provide input signals and receive output signals, which may be the same as the case of a conventional mobile communication terminal.

[0166] Based on different communication technologies, multiple communication modules 110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module, and / or a wireless local area network module. The communication module 110 (transmitter / receiver) is also coupled to a speaker 131 and a microphone 132 via an audio processor 130 to provide audio output via the speaker 131 and receive audio input from the microphone 132, thereby implementing common telecommunication functions. The audio processor 130 may include any suitable buffer, decoder, amplifier, etc. Furthermore, the audio processor 130 is coupled to the central processing unit 100, enabling local recording via the microphone 132 and playback of stored audio via the speaker 131.

[0167] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0168] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0169] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0170] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0171] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. An image quality analysis method based on frustum geometric constraints and negative feedback control, characterized in that: The method comprises: Step S1: Obtaining vertical chromatic aberration, axial chromatic aberration, and wave chromatic aberration of a multi-conjugate catadioptric zoom system; Step S2: solving the wavefront aberration of the multi-conjugation catadioptric zoom system after wavelength modulation under the condition of multi-conjugation of focal length and wavelength; Step S3: determining the characteristic aberration node position of the multi-conjugate catadioptric zoom system according to the wavefront aberration and calculating the RMS spot diameter within the set range of the central field of view; Step S4: Using the frustum geometric constraint, the vertical axis chromatic aberration and the axial chromatic aberration correction method, and the material Abbe number as a variable, the position of the characteristic aberration node is negatively feedback controlled to suppress the influence of chromatic aberration, and the imaging quality of the multi-conjugate catadioptric zoom system within the full focal length and full band is comprehensively analyzed.

2. The image quality analysis method based on frustum geometric constraints and negative feedback control according to claim 1, characterized in that: The step S2 further comprises: Step S21: sampling focal length intervals in the multi-conjugate catadioptric zoom system, setting a spectral range, and selecting spectral lines; Step S22: solving the wavefront aberration of the catadioptric zoom system after wavelength modulation under the condition of multiple conjugation of focal length and wavelength; Step S23: Repeat the above steps S21-S22 at all sampling focal lengths in the full focal range to obtain the output wavefront aberration values ​​of the multi-conjugate catadioptric zoom system at multiple conjugate positions within the full focal range and full wavelength range.

3. The image quality analysis method based on frustum geometric constraints and negative feedback control according to claim 2, characterized in that: The step S22 further includes: Step S221: Using wavefront aberration as a basis for evaluating and correcting errors in light propagating through the optical system, the complex wavefront at the lens exit is decomposed into wavefront aberrations of different types of bases; Step S222: calculating the coefficient value of the wavefront aberration of the multi-conjugate catadioptric zoom system at the focal length for different sampling wavelengths; Step S223: Calculating the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal length positions is completed using the deformable device.

4. The image quality analysis method based on frustum geometric constraints and negative feedback control according to claim 1, characterized in that: The step S3 further comprises: Step S31: sampling the field of view within the full field of view, calculating the vector aberration of various aberration items under all sampled fields of view, and obtaining an aberration full field of view map; Step S32: determining whether the system has a characteristic aberration node according to the aberration full field of view map, and calculating the position of the characteristic aberration node; Step S33: Calculate the RMS spot diameter within the set range of the central field of view.

5. The image quality analysis method based on frustum geometric constraints and negative feedback control according to claim 1, characterized in that: The step S4 further comprises: Step S41: establishing frustum geometric constraints; Step S42: determining whether the characteristic aberration node position within the full focal length and full wavelength range is included in the geometric constraints, and performing negative feedback control on the characteristic aberration node position by using the vertical axis chromatic aberration and the axial axis chromatic aberration correction method and the material Abbe number as a variable; Step S43: Calculate the variance value from the characteristic aberration node position to its centroid within the full band range at all sampling focal lengths, and the RMS spot diameter root mean square value of each sampling field within the frustum geometric constraint range as system image quality evaluation indicators.

6. An image quality analysis device based on frustum geometric constraints and negative feedback control, characterized in that: The device comprises: A chromatic aberration acquisition unit, used for acquiring vertical axis chromatic aberration, axial chromatic aberration and wave chromatic aberration of the multi-conjugate catadioptric zoom system; a wavefront aberration solving unit, configured to solve the wavefront aberration of the multi-conjugated catadioptric zoom system after wavelength modulation under the condition of multi-conjugated focal length and wavelength; a position and spot determination unit, configured to determine the characteristic aberration node position of the multi-conjugate catadioptric zoom system according to the wave aberration and calculate the RMS spot diameter within a set range of the central field of view; A control and analysis unit is used to use the frustum geometric constraint, the vertical axis chromatic aberration and the axial chromatic aberration correction method, and the material Abbe number as a variable to negatively feedback control the position of the characteristic aberration node to suppress the influence of chromatic aberration, and comprehensively analyze the imaging quality of the multi-conjugate catadioptric zoom system within the full focal length and full band range.

7. The image quality analysis device based on frustum geometric constraints and negative feedback control according to claim 6, characterized in that: The wave aberration solving unit includes: a sampling setting module, for sampling focal length intervals in the multi-conjugate catadioptric zoom system, and setting spectral ranges and selecting spectral lines; A solution module for solving the wavefront aberration of a catadioptric zoom system under the conditions of multiple conjugation of focal length and wavelength after wavelength modulation; The sampling setting module and the solving module are executed in sequence until the output wave aberration value of the multi-conjugate catadioptric zoom system at the multi-conjugate position within the full focal length and full wavelength range is obtained.

8. The image quality analysis device based on frustum geometric constraints and negative feedback control according to claim 7, characterized in that: The solution module includes: A disassembly submodule is used to use wavefront aberration as a basis for evaluating and correcting errors caused by light propagating through the optical system, and to disassemble the complex wavefront at the lens exit into wavefront aberrations of different types of bases; A first calculation submodule is configured to calculate, for different sampling wavelengths, coefficient values ​​of wavefront aberration of the multi-conjugate catadioptric zoom system at the focal length; The second calculation submodule is used to calculate the wavefront aberration at different sampling wavelengths after the free-form surface shape design at all focal length positions is completed using the deformable device.

9. The image quality analysis device based on frustum geometric constraints and negative feedback control according to claim 6, characterized in that: The position and light spot determination unit includes: The field of view map acquisition module is used to sample the field of view within the full field of view, calculate the vector aberration of various aberration items under all sampled fields of view, and obtain the full field of view aberration map; A node calculation module is used to determine whether there is a characteristic aberration node in the system according to the aberration full field of view map, and calculate the position of the characteristic aberration node; The RMS spot calculation module is used to calculate the RMS spot diameter within the set range of the central field of view.

10. The image quality analysis device based on frustum geometric constraints and negative feedback control according to claim 6, characterized in that: The regulation and analysis unit includes: Frustum constraint establishment unit, used to establish frustum geometric constraints; a feedback control module, configured to determine whether the characteristic aberration node position within the full focal length and full wavelength range is contained within the geometric constraints, and to perform negative feedback control on the characteristic aberration node position using the vertical axis chromatic aberration and the axial axis chromatic aberration correction method and the material Abbe number as a variable; The image quality analysis module is used to calculate the variance value from the characteristic aberration node position to its center of mass within the full band range at all sampling focal lengths, and the RMS spot diameter root mean square value of each sampling field within the frustum geometric constraint range, as the system image quality evaluation index.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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