Method for obtaining phase retardation map and fast axis direction map of cornea and related device

Abstract

This application discloses a method and related apparatus for obtaining a phase retardation map and a fast axis orientation map of the cornea. The method includes inputting a preset polarization state into a metasurface polarization analyzer to obtain polarization measurement data output by the metasurface polarization analyzer; solving for polarization state matrix parameters based on the polarization measurement data; and decomposing the polarization state matrix parameters to obtain a phase retardation map and a fast axis orientation map of the cornea. Using this application embodiment, subtle microstructural changes in the cornea can be captured with high sensitivity, compensating for the lack of quantitative analysis methods in traditional slit-lamp examinations, while effectively overcoming the problem of insufficient accessibility caused by the large size and high cost of traditional high-end detection equipment.

Description

Technical Field

[0001] This invention relates to the field of ophthalmic optical inspection and slit-lamp imaging technology, and particularly to a method and related apparatus for obtaining a phase delay map and fast axis direction map of the cornea. Background Technology

[0002] As the transparent tissue at the very front of the eyeball, the cornea is not only the first refractive medium through which light enters the eye, but its structural integrity directly affects visual quality and serves as a "window" reflecting the health of the eyes and even the entire body. Accurate assessment of the corneal microstructure and physiological state is of crucial clinical value for the diagnosis and monitoring of various diseases. Besides keratoconus, changes in corneal morphology and biomechanical properties are closely related to glaucoma, dry eye syndrome, corneal dystrophy, infectious keratitis, and diabetic neuropathy. For example, corneal thickness and hardness are key factors affecting intraocular pressure measurements and glaucoma risk assessment; while changes in corneal nerve density and morphology are important biomarkers for the early diagnosis of diabetic peripheral neuropathy.

[0003] Currently, there are various methods for examining the cornea in clinical practice, but all have certain limitations. While routine slit-lamp microscopy is fundamental in ophthalmology, it relies heavily on the doctor's subjective interpretation and lacks the ability to generate quantitative structural maps, making it difficult to detect subtle early lesions. High-end corneal topography or biomechanical analyzers, although providing corneal morphology or overall biomechanical parameters, are often expensive, bulky, and have limited availability. Furthermore, these devices mostly focus on assessing macroscopic morphology or overall mechanical properties; there is still a lack of a cost-effective, easy-to-operate method that can provide high-resolution quantitative distribution maps for detecting the birefringence characteristics of corneal microstructures (such as collagen fiber orientation). Summary of the Invention

[0004] This application provides a method and related apparatus for obtaining phase delay maps and fast axis direction maps of the cornea, which can capture subtle microstructural changes of the cornea with high sensitivity, making up for the lack of quantitative analysis methods in traditional slit-lamp examination, and effectively overcoming the problem of insufficient popularity caused by the large size and high cost of traditional high-end detection equipment.

[0005] The first aspect of this application provides a method for obtaining a phase retardation map and a fast axis orientation map of the cornea, the method comprising: The preset polarization state is input into the metasurface polarization analyzer to obtain the polarization measurement data output by the metasurface polarization analyzer; Solve for the polarization state matrix parameters based on the polarization measurement data; By decomposing the polarization state matrix parameters, a phase delay map and a fast axis orientation map of the cornea are obtained.

[0006] Optionally, the polarization state matrix parameters include Stokes parameters or Mueller matrices, and the step of solving the polarization state matrix parameters based on the polarization measurement data includes: If the preset polarization state is a single fixed state, then the Stokes parameters are solved based on the polarization measurement data and the weighted least squares method. If the number of preset polarization states is less than the maximum number of polarization analysis channels formed by the metasurface polarization analyzer within the same exposure window, then the constrained Mueller matrix is ​​solved based on the polarization measurement data and constrained optimization. If the number of preset polarization states is equal to the maximum number of polarization analysis channels formed by the metasurface polarization analyzer within the same exposure window, then the complete Mueller matrix is ​​solved by standard decomposition based on the polarization measurement data. The restricted Mueller matrix has fewer independent parameters than the complete Mueller matrix.

[0007] Optionally, the formula for determining the Stokes parameter is: , in, For Stokes parameters, The analysis matrix obtained by calibrating the metasurface polarization analyzer. For the preset weight matrix, This is polarization measurement data.

[0008] Optionally, the formula for determining the Mueller matrix is: , in, For Muller matrix, The Mueller matrix for the optimal solution. For the first The polarization state at the th ... Observations from each polarization analysis channel For the first The vector corresponding to each polarization analysis channel For the first One polarization state, This refers to the prior physical constraints or penalties imposed on the Mueller matrix.

[0009] Optionally, the method further includes: The reliability of the phase delay map and the fast axis direction map is determined according to the quality control and rejection or degradation mechanism; When the reliability of the phase delay map and the fast axis direction map is determined to be satisfactory, the phase delay map and the fast axis direction map are output.

[0010] Optionally, the step of judging the reliability of the phase delay map and the fast axis direction map according to the quality control and rejection or degradation mechanism includes: The polarization quality assessment parameters are obtained, including image quality parameters, region parameters, basic parameters, and advanced parameters. The image quality parameters are parameters extracted based on the statistical features of the original light intensity image. The region parameters are statistical quantities describing the consistency of the spatial distribution of the image. The basic parameters are polarization state description quantities obtained by directly solving the Stokes parameters or Mueller matrix. The advanced parameters are physical quantities that need to be obtained by performing complex mathematical inversion calculations on the basic parameters. The system sequentially performs a severe defect determination based on the image quality parameters, a region validity determination based on the region parameters, and a parameter reliability determination based on the basic and advanced parameters.

[0011] Optionally, the method further includes: Based on the phase delay map and the fast axis orientation map, corneal birefringence structural features are extracted from the region of interest. The corneal birefringence structural features include phase delay statistical features, gradient energy features, and orientation consistency features. Calculate the corneal birefringence structure score based on the corneal birefringence structure characteristics; The user's keratoconus is managed throughout its entire lifecycle based on the corneal birefringence structure score.

[0012] A second aspect of this application provides a device for acquiring a phase delay map and a fast axis orientation map of the cornea, the device comprising: A polarization measurement unit is used to input a preset polarization state to a metasurface polarization analyzer to obtain polarization measurement data output by the metasurface polarization analyzer. A polarization state matrix parameter solving unit is used to solve for polarization state matrix parameters based on the polarization measurement data; The map parameter determination unit is used to decompose the polarization state matrix parameters to obtain the phase delay map and fast axis direction map of the cornea.

[0013] A third aspect of this application provides an electronic device, including: a processor and a memory; The processor is connected to a memory, wherein the memory is used to store computer programs and the processor is used to invoke the computer programs to execute the methods as described in the first aspect of the embodiments of this application.

[0014] A fourth aspect of this application provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, perform the method as described in the first aspect of this application.

[0015] This application, by solving for the polarization state matrix parameters and decomposing them to obtain the phase delay map and fast axis orientation map of the cornea, can highly sensitively capture subtle microstructural changes in the cornea. This overcomes the lack of quantitative analysis methods in traditional slit-lamp examinations, providing more accurate structurally sensitive indicators for the early diagnosis and disease progression monitoring of ophthalmic diseases. This application uses a metasurface polarization analyzer instead of traditional discrete optical components, utilizing its flexible control over light field polarization information at the subwavelength scale to transform the complex mechanical rotation scanning process into a "snapshot" spatial intensity encoding. This not only significantly simplifies the optical path system structure and reduces equipment costs but also enables rapid polarization measurement under a single exposure. This feature effectively overcomes the problem of insufficient accessibility caused by the large size and high cost of traditional high-end detection equipment, while avoiding measurement errors caused by eye movement, significantly improving detection efficiency and stability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. 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 effort.

[0017] Figure 1 A schematic diagram of a slit-cutting band polarization measurement system provided in one embodiment of this application is shown; Figure 2 A schematic flowchart of a method for obtaining a phase delay map and a fast axis orientation map of the cornea according to an embodiment of this application is shown. Figure 3 This invention provides a schematic diagram of the structure of a device for acquiring a phase delay map and a fast axis orientation map of the cornea according to an embodiment of this application. Figure 4 A schematic diagram of the structure of a computer device provided in one embodiment of this application is shown. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] Please refer to Figure 1 This diagram illustrates a slit-cutting band polarization measurement system according to an embodiment of this application. Wherein: The slit lamp body (100) provides stable mechanical support, an illumination channel, and an observation channel; the observation path (101) is used to collect corneal reflected light and direct it to subsequent analysis components.

[0020] The illumination path (110) is used to project a preset polarized illumination onto the corneal surface, and the scission band (111) is used to define the width, direction and incident geometry of the illumination beam, thereby forming different scission band configuration parameters.

[0021] An optional polarization state generator (PSG) (130) is used to switch the incident polarization state on the input side; an input state switch (131) is used to switch between multiple linear polarization states or other preset polarization states to facilitate subsequent polarization measurements.

[0022] A pluggable module (120) is set on the output side of the observation path (101) to complete polarization analysis and imaging; wherein, the metasurface polarization state analyzer (PSA) (121) is used to decompose the returned light into multiple polarization analysis channels, the imaging lens group (122) is used to image the light field corresponding to the analysis channel onto the camera (123), and the camera (123) is used to acquire images of each channel.

[0023] The eye (200) represents the object being measured, and the scattering / reflecting medium (210) represents the scattering, reflection, and birefringence modulation of incident polarized light by the anterior surface and superficial stroma of the cornea.

[0024] The data link (310) is used to transmit the image data and corresponding configuration parameters acquired by the camera (123) to the processing unit (300); the processing unit (300) is used to perform parameter acquisition control, Stokes parameter or Mueller matrix solving, phase delay and fast axis direction reconstruction, layer fusion, quality gating, report export and other processing.

[0025] When the system is working, the illumination path (110) emits tangential illumination to the cornea under given incident angle, tangential width, observation angle and exposure settings; the corneal modulated return light enters the pluggable module (120) through the observation path (101), polarization analysis is completed by the metasurface PSA (121), and multi-channel imaging is completed by the imaging lens group (122) and the camera (123); the processing unit (300) reconstructs and fuseds the data under multiple tangential configurations, thereby outputting a phase delay map and fast axis orientation map dominated by the anterior corneal surface structure.

[0026] Please refer to Figure 2This illustration shows a flowchart of a method for obtaining a corneal phase retardation map and a fast axis orientation map according to an embodiment of this application. This method can be applied to a computer device, which refers to an electronic device with data computing and processing capabilities. The method may include the following steps: Step 201: Input the preset polarization state into the metasurface polarization analyzer to obtain the polarization measurement data output by the metasurface polarization analyzer.

[0027] The metasurface polarization analyzer integrates multiple polarization analysis channels (such as nanostructured gratings) in different directions. When a beam of light with a known polarization state (i.e., a preset polarization state) is incident on the analyzer, each channel outputs a light intensity value after passing through it. These intensity values ​​collectively constitute the polarization measurement data. This data reflects the projected intensity of the incident light along different analysis directions, providing raw information for subsequent calculations of the polarization state matrix parameters.

[0028] For example, the metasurface polarization analyzer forms at least four polarization analysis channels within the same exposure window based on the input polarization state, such as light intensities at angles of 0°, 45°, 90°, and 135°. , , , The obtained polarization measurement data is used with the observation vector If we express this as an expression, then the relationship between the observation vector and the light intensity is: .

[0029] Step 202: Solve for the polarization state matrix parameters based on the polarization measurement data.

[0030] In this process, using the multiple light intensity measurements obtained in the previous step, the polarization state matrix parameters that can completely describe the polarization state of the incident light are solved through mathematical inversion or optimization algorithms. The polarization state matrix parameters include Stokes parameters or Mueller matrices.

[0031] Among them, the Stokes vector It is a column vector consisting of four real numbers that can completely describe the intensity and polarization state of a beam of light (including fully polarized, partially polarized, and unpolarized light). For example, it can be represented as... , Total light intensity , For linearly polarized components, It represents the circular polarization component.

[0032] When the input is a single polarization state, the Stokes parameters are obtained by solving the polarization measurement data. For example, the relationship between the two is as follows: ,in, For system matrix or measurement matrix, This is the noise term.

[0033] Among them, the Mueller matrix It is a 4×4 real matrix that describes how the polarization state of light changes after passing through an optical element or medium (such as the cornea).

[0034] When the input is a multi-polarization state, the result obtained by solving the polarization measurement data is the Mueller matrix. For example, the relationship between the two is as follows: ,in, In the first incident polarization state and the Under each analytical state In position The scalar output signal (usually light intensity) measured at the point. This is the noise term.

[0035] Specifically, the step of solving the polarization state matrix parameters based on the polarization measurement data includes: If the preset polarization state is a single fixed state, then the Stokes parameters are solved based on the polarization measurement data and the weighted least squares method. If the number of preset polarization states is less than the maximum number of polarization analysis channels formed by the metasurface polarization analyzer within the same exposure window, then the constrained Mueller matrix is ​​solved based on the polarization measurement data and constrained optimization. If the number of preset polarization states is equal to the maximum number of polarization analysis channels formed by the metasurface polarization analyzer within the same exposure window, then the complete Mueller matrix is ​​solved by standard decomposition based on the polarization measurement data. The restricted Mueller matrix has fewer independent parameters than the complete Mueller matrix.

[0036] The preset polarization state is a single fixed state, meaning only one known and unchanging polarization state, such as horizontally linearly polarized light, is input to the cornea. Multiple analysis channels of the metasurface polarization analyzer simultaneously detect the intensity distribution of the emitted light, obtaining a set of measurement data. Because the number of measurement channels is typically greater than four, and the number of equations exceeds the number of unknowns, the optimal solution can be obtained by minimizing the weighted sum of squared residuals.

[0037] For example, the formula for determining the Stokes parameter is: , in, For Stokes parameters, The analysis matrix obtained by calibrating the metasurface polarization analyzer. For the preset weight matrix, This is polarization measurement data. Weight matrix. The accuracy of the solution can be improved by setting the signal-to-noise ratio or measurement uncertainty of each channel.

[0038] Among them, the complete 4×4 Mueller matrix There are 16 independent parameters, but in some scenarios, such as when the cornea mainly exhibits linear birefringence and circular dichroism can be ignored, or when all parameters cannot be independently distinguished due to measurement limitations, a restricted Mueller matrix with fewer independent parameters can be solved, such as a simplified model that only includes linear birefringence and linear dichroism, in which case there may be only 7 to 9 independent parameters.

[0039] To solve the Mueller matrix, a set of polarization analysis channel data is collected for each input polarization state. Since the number of input polarization states is less than the maximum number of polarization analysis channels, the total amount of measurement data is insufficient to unambiguously and completely solve the 16 parameters of the Mueller matrix. Therefore, physical constraints or prior knowledge must be introduced, such as the physical realizability conditions that the Mueller matrix must satisfy, energy conservation, certain elements being 0 or symmetric, etc., to confine the solution of the optimization problem within a subspace, thereby obtaining a stable and reasonable constrained Mueller matrix.

[0040] The formula for determining the Mueller matrix is ​​as follows: , in, For Muller matrix, The Mueller matrix for the optimal solution. For the first The polarization state at the th ... Observations from each polarization analysis channel For the first The vector corresponding to each polarization analysis channel For the first One polarization state, This refers to the prior physical constraints or penalties imposed on the Mueller matrix.

[0041] Standard decomposition specifically refers to a non-iterative, closed-form method for solving the Mueller matrix based on direct linear algebraic inversion. Combining all input polarization states and all polarization analysis channels can be expressed as a matrix equation. When the number of polarization states equals the maximum number of polarization analysis channels, the Mueller matrix can be directly solved through two matrix inversions, without iterative optimization or additional physical constraints. Step 203: Decompose the polarization state matrix parameters to obtain the phase delay map and fast axis direction map of the cornea.

[0042] Among them, phase delay map Phase delay parameter Depending on location The change in phase retardation represents the cumulative phase difference between two orthogonally polarized components after a light wave passes through the corneal tissue. The corneal stroma is mainly composed of neatly arranged collagen fibers and exhibits birefringence. The magnitude of the phase retardation directly reflects the density, orderliness, and thickness of the corneal tissue. In the early stages of keratoconus, disordered or broken collagen fibers can lead to a decrease in local birefringence, which manifests on the corneal map as an abnormally low or uneven distribution of the phase retardation value.

[0043] Among them, the fast axis direction map Fast axis direction parameter Depending on location The change in the fast axis indicates the angle of polarization direction at a point on the cornea where light waves propagate fastest. The fast axis direction is usually perpendicular or parallel to the main alignment direction of local collagen fibers. In normal corneas, the fast axis direction exhibits a highly consistent radial or circumferential arrangement pattern. Keratoconus causes distortion of the fiber arrangement, resulting in a chaotic, abrupt, or vortex-like fast axis pattern.

[0044] For example, for purely linear birefringence, Stokes parameter decomposition is used to determine the circular polarization components. Typically close to 0, the main information is concentrated on and Therefore, the direction of the fast axis determines the principal direction of birefringence, and the fast axis direction map can be represented as: .

[0045] Phase retardation reflects the strength of birefringence (proportional to corneal thickness and birefringence). It is determined by the "latitude" of the polarization state on the Poincaré sphere: , The polarization degree of the incident light.

[0046] For example, the Mueller matrix can be decomposed as follows: , For the depolarization matrix, Let be the delay matrix. Let be the dichroism matrix. The fast axis direction map can be represented as: , For matrix The first in Line 1 Column elements, This is a submatrix of size 3×3 that contains only birefringence information after purification.

[0047] , For matrix The traces.

[0048] This application, by solving for the polarization state matrix parameters and decomposing them to obtain the phase delay map and fast axis orientation map of the cornea, can highly sensitively capture subtle microstructural changes in the cornea. This overcomes the lack of quantitative analysis methods in traditional slit-lamp examinations, providing more accurate structurally sensitive indicators for the early diagnosis and disease progression monitoring of ophthalmic diseases. This application uses a metasurface polarization analyzer instead of traditional discrete optical components, utilizing its flexible control over light field polarization information at the subwavelength scale to transform the complex mechanical rotation scanning process into a "snapshot" spatial intensity encoding. This not only significantly simplifies the optical path system structure and reduces equipment costs but also enables rapid polarization measurement under a single exposure. This feature effectively overcomes the problem of insufficient accessibility caused by the large size and high cost of traditional high-end detection equipment, while avoiding measurement errors caused by eye movement, significantly improving detection efficiency and stability.

[0049] Furthermore, the method also includes: The reliability of the phase delay map and the fast axis direction map is determined according to the quality control and rejection or degradation mechanism; When the reliability of the phase delay map and the fast axis direction map is determined to be satisfactory, the phase delay map and the fast axis direction map are output.

[0050] Specifically, the determination of the reliability of the phase delay map and the fast axis direction map based on the quality control and rejection or degradation mechanism includes: The polarization quality assessment parameters are obtained, including image quality parameters, region parameters, basic parameters, and advanced parameters. The image quality parameters are parameters extracted based on the statistical features of the original light intensity image. The region parameters are statistical quantities describing the consistency of the spatial distribution of the image. The basic parameters are polarization state description quantities obtained by directly solving the Stokes parameters or Mueller matrix. The advanced parameters are physical quantities that need to be obtained by performing complex mathematical inversion calculations on the basic parameters. The system sequentially performs a severe defect determination based on the image quality parameters, a region validity determination based on the region parameters, and a parameter reliability determination based on the basic and advanced parameters.

[0051] Among them, the basic parameters are highly robust to noise, while the advanced parameters are extremely sensitive to noise and are mainly used to characterize birefringence or stress properties.

[0052] Specifically, the image quality parameters include image gradient, image sharpness, image saturated pixel ratio, and image effective pixel ratio. The determination of severe defects based on the image quality parameters includes: If the image gradient is less than or equal to a preset image gradient, or if the image sharpness is less than or equal to a preset image sharpness, then the image is determined to be severely out of focus. If the percentage of saturated pixels in the image is greater than or equal to the preset percentage of saturated pixels in the image, then the image is determined to be oversaturated. If the effective pixel percentage of the image is less than or equal to the preset effective pixel percentage of the image, then the image is determined to be significantly occluded. If the image is severely out of focus, oversaturated, or significantly obscured, it is determined that the image has serious defects and will fail to pass the test. The image quality is also indicated as severely damaged. Please adjust the equipment and retake the image.

[0053] Image gradient refers to the rate of change of pixel values ​​in a spatial direction, typically calculated using operators such as Sobel and Scharr. The gradient magnitude reflects the richness of detail in an image, including edges and textures. In corneal polarization measurements, a low gradient value indicates a blurred image or poor contrast, possibly due to poor focusing or tear film abnormalities; an abnormal gradient distribution may indicate noise or artifacts.

[0054] Image sharpness describes the clarity of edges in an image and is often quantified by indicators such as gradient energy, point spread function width, or the proportion of high-frequency components in the frequency domain. High sharpness means sharp edges, which is beneficial for accurately extracting corneal boundaries and polarization features; low sharpness indicates optical system defocus, eye movement, or astigmatism, which will reduce the accuracy of polarization parameter solving.

[0055] In this context, the saturated pixel ratio refers to the proportion of pixels in the entire image whose grayscale or color channel values ​​reach the sensor's maximum quantization level. An excessively high ratio indicates overexposure in certain areas, leading to truncation of light intensity information and consequently distorting the calculation of Stokes parameters or Mueller matrix elements. In polarization measurements, saturated pixels disrupt linear response and should be discarded or flagged.

[0056] The effective pixel percentage refers to the proportion of pixels that can be used for subsequent analysis after removing invalid areas (such as eyelid occlusion, non-corneal areas outside the limbus, pixels dominated by dark noise, saturated pixels, etc.). This metric reflects the usability of the measurement data and helps determine whether the current frame contains enough corneal polarization signal.

[0057] It should be noted that if the image is severely out of focus, it indicates a lack of high-frequency details, making accurate pixel-level polarization calculation impossible; if the image is oversaturated, Stokes vector calculations will suffer from truncation errors, leading to incorrect polarization degree calculations; if the image is significantly occluded, global statistics lose their representativeness. Therefore, in these cases, the phase delay map and fast axis direction map calculations are incorrect and do not need to be output; if calculations have not yet started, they are unnecessary and the calculated results will also be incorrect, thus saving computation time.

[0058] Specifically, the image quality parameters include channel registration residuals, and the determination of severe defects based on the image quality parameters includes: If the channel registration residual is greater than or equal to the preset channel registration residual threshold, the image is determined to have serious defects and fails to pass the test, and the multi-channel image alignment fails. Please check the optical system or recalibrate.

[0059] In this context, channel registration residual refers to the spatial registration error between different polarization channels in a polarization measurement system (e.g., images acquired at 0°, 45°, 90°, 135°, or four images acquired in different delay directions). Due to eye movement or system optical path deviations, sub-pixel misalignment may exist in the images of each channel; the residual is the remaining deviation of the corresponding pixel position after registration. Excessive residual can introduce severe artifacts when calculating Stokes parameters, especially causing irreversible distortion of high-frequency polarization information. Similarly, in this case, the phase delay map and fast axis direction map are calculated incorrectly and do not need to be output; if calculation has not started, it is unnecessary to perform the calculation, and the calculated result will also be incorrect, thus saving computation time.

[0060] Specifically, the regional parameters include full-caliber statistics and statistics of interest, and the determination of regional validity based on the regional parameters includes: If the full-caliber statistic exceeds the quality control range and the statistic of interest is within the normal range, then the partial pass is determined and the statistic of interest and the phase delay map are output.

[0061] Among them, the full-aperture statistic refers to the statistical value calculated for the entire measurement area of ​​the original light intensity image. This statistical value can be, for example, the mean, variance, standard deviation, etc., and it reflects the overall quality. The statistic of interest refers to the statistical value calculated only for a specific, key local area (Region of Interest, ROI) in the original light intensity image, such as the corneal region.

[0062] If the total statistic exceeds the quality control range while the statistic of interest is within the normal range, the two statistics can be the same, for example, the total mean exceeds the first preset mean range while the mean of the region of interest is within the second preset mean range; the two statistics can also be different, for example, the total mean exceeds the first preset mean range while the standard deviation of the region of interest is within the first preset standard range; the number of the two statistics can be the same, as in the two examples mentioned above; the number of the two statistics can also be different, for example, the total mean exceeds the first preset mean range while the mean of the region of interest is within the second preset mean range and the standard deviation of the region of interest is within the first preset standard range; here, no limitation is made.

[0063] It should be noted that the fast-axis orientation map is usually related to the "fast-axis azimuth" of the birefringent material, a parameter that is highly sensitive to overall measurement conditions (such as illumination uniformity, sample orientation, and background noise). When the overall aperture statistics are unstable (i.e., poor overall quality), the calculated fast-axis orientation map will be unreliable and therefore unsuitable for output. The phase retardation map represents the optical path difference or phase retardation, a parameter that often exhibits good robustness in local regions (regions of interest). Therefore, as long as the quality of the local region is normal, even if the overall measurement environment fluctuates, the phase retardation map for that region will still be accurate and reliable.

[0064] Specifically, the basic parameters include signal-to-noise ratio, linear polarization degree, and intensity; the advanced parameters include directional stability and polarization leakage; and the parameter reliability determination based on the basic and advanced parameters includes: If the signal-to-noise ratio is less than or equal to a preset signal-to-noise ratio threshold, or the polarization leakage is greater than or equal to a preset polarization leakage threshold, or the directional stability is less than or equal to a preset directional stability threshold, then the basic parameters are determined to be reliable and the advanced parameters to be unreliable, and the degree of linear polarization and intensity are output.

[0065] Intensity usually refers to the first component of the Stokes vector, i.e., the total light intensity mentioned above. Intensity reflects the brightness information of the scene and is the basis for calculating the signal-to-noise ratio.

[0066] The signal-to-noise ratio (SNR) refers to the ratio of signal power to noise power. for: , The average gray value of the region of interest. The standard deviation is the background or uniform region.

[0067] The degree of linear polarization is the proportion of linearly polarized light components in the beam. The degree of polarization can be determined based on the Stokes vector. Determine, for example, the degree of linear polarization and total polarization degree for: , .

[0068] Ideally, the channel for measuring horizontally polarized light should only receive the horizontal component. However, in practical optical systems, due to imperfections in the components (such as waveplate defects or detector anisotropy), non-target polarization components can also enter the channel; this phenomenon is called polarization leakage. It is typically represented by the off-diagonal elements of the Stokes matrix or the Mueller matrix. Or use option D to quantify.

[0069] The directional stability is characterized by at least one of directional consistency, directional variance, and quantiles of angular deviation within the region of interest. The directional consistency is obtained using 2-degree circumferential statistics based on the π-periodity of the fast-axis directional map. The formula for calculating the directional consistency is: , in, For consistency of direction, The number of effective observation units selected. This is the fast axis direction map for the i-th valid unit. The imaginary unit is the direction of the fast axis. and equivalence; The formula for calculating the directional variance is: , in, For directional variance, The formula for calculating the quantiles of the angular deviation within the region of interest is: in, The quantiles of the angular deviation, This means that for all x, the i-th x, y ... Percentiles, for example, can be 95, 98, or other values; no limitation is made here. To be Limited to Within the interval, This is the average value of the map for all fast axis directions.

[0070] It should be noted that insufficient directional stability and excessive polarization leakage mean that, under the current measurement conditions, it is impossible to stably calculate the fast axis direction or phase delay of the birefringent material using algorithms. Although high-order solutions are not possible, the raw linear polarization degree and light intensity data are still accurate and usable, and therefore can be output.

[0071] Specifically, the advanced parameters also include a phase delay map and a fast axis orientation map, and the method further includes: If the severe defect determination, the region validity determination, and the parameter reliability determination all pass, then the phase delay map and the fast axis direction map are output.

[0072] It should be noted that if all three levels of quality control judgments are passed, it means that the calculated phase delay map and fast axis direction map are relatively reliable and can be output.

[0073] Furthermore, the method also includes: Calculate the continuous quality control score based on the polarization quality assessment parameters; If the continuous quality control score is less than or equal to the preset continuous quality control score threshold, then the quality control is confirmed to have passed. If the continuous quality control score is greater than the preset continuous quality control score threshold, then the quality control is deemed unsuccessful.

[0074] Specifically, the formula for calculating the continuous quality control score is as follows: in, For continuous quality control scores. For the first The actual values ​​of each polarization quality assessment parameter For the first The expected value of each polarization quality assessment parameter For the first The standard deviation of each polarization quality assessment parameter Used to Limited to Within the interval, for The corresponding weights For the first Quality control scores for each polarization quality assessment parameter.

[0075] The polarization quality assessment parameters can be the image quality parameters, region parameters, basic parameters, and advanced parameters mentioned above. The continuous quality control score is calculated in the first stage relative to the image quality parameters. If the quality control score of the image quality parameters is greater than the corresponding preset quality control score threshold, a quality control score relative to the region parameters is further calculated. If the quality control score of the region parameters is greater than the corresponding preset quality control score threshold, a quality control score relative to the basic parameters is further calculated. If the quality control score of the basic parameters is greater than the corresponding preset quality control score threshold, a quality control score relative to the advanced parameters is further calculated. If the quality control score of the advanced parameters is greater than the corresponding preset quality control score threshold, the quality control is confirmed to have passed.

[0076] Of course, you can also skip the above classification of image quality parameters, region parameters, basic parameters, and advanced parameters, and use other classifications, or you can directly calculate the polarization quality assessment parameters one by one without classification. There are no restrictions here.

[0077] Furthermore, even without passing quality control, corresponding reason codes can be output. For example, severe image defocus corresponds to the reason code RC_DEFOCUS, image oversaturation corresponds to the reason code RC_SATURATION, significant image occlusion corresponds to the reason code RC_OCCLUSION, multi-channel image alignment failure corresponds to the reason code RC_MISALIGNMENT, edge occlusion / abnormality caused by abnormal full-aperture statistics corresponds to the reason codes RC_PARTIAL_VALID or RC_OCCLUSION, insufficient signal-to-noise ratio corresponds to the reason code RC_LOW_SNR, excessive polarization leakage corresponds to the reason code RC_LEAKAGE_HIGH, insufficient directional stability, and unreliable fast-axis calculation correspond to the reason code RC_DIR_UNSTABLE, etc.

[0078] Furthermore, quality control logs and export packages can be output, including a quality control threshold table. This table is invoked during the quality control decision-making phase for hard gating and / or continuous quality score normalization. Its version number is also written to the quality control logs and export packages for audit traceability and subsequent reproduction. Therefore, it is not only "output" but also actually used in the decision-making process.

[0079] The quality control threshold table can be configured differently according to equipment model, band, or acquisition scheme. Different equipment models have different imaging resolutions and noise characteristics, so different sharpness thresholds can be used; different bands have different effects on tissue scattering and signal-to-noise ratio, so different SNR thresholds can be used; different acquisition schemes (rapid screening / high-precision mode) can be configured with different motion thresholds, saturation thresholds, and directional stability thresholds.

[0080] Furthermore, the quality control log may also include the device serial number, calibration version, key quality fields, pass / fail flags, reason codes, and hash digests.

[0081] Furthermore, the method also includes: Based on the phase delay map and the fast axis orientation map, corneal birefringence structural features are extracted from the region of interest. The corneal birefringence structural features include phase delay statistical features, gradient energy features, and orientation consistency features. Calculate the corneal birefringence structure score based on the corneal birefringence structure characteristics; The user's keratoconus is managed throughout its entire lifecycle based on the corneal birefringence structure score.

[0082] The Region of Interest (ROI) refers to a specific region of analysis selected from the entire corneal image.

[0083] The phase delay statistical features are characteristics obtained by statistical analysis of the phase delay parameters within the ROI, including at least one of the following: mean phase delay, standard deviation of phase delay, and phase delay quantiles, wherein the phase delay quantiles can be, for example, [missing information - likely related to a specific feature or characteristic]. , i.e., variables The 95th percentile, or any other percentile, is not limited here. The overall birefringence of the cornea in patients with keratoconus is often lower than in normal individuals, and due to the mixture of diseased and normal areas, the value fluctuates more significantly. This characteristic is used to assess the overall integrity of the corneal stroma.

[0084] The gradient energy feature calculates the rate of change of the phase delay map or fast axis direction map in position and obtains the gradient energy, which is characterized by the energy gradient. In keratoconus lesion boundaries or stress concentration areas, the birefringence parameters change drastically. A high gradient energy indicates a dramatic structural transition or anomaly within that region. The gradient energy feature helps identify minute, localized structural collapse points that might be masked by simple statistical averages. This feature reflects the local instability and stress concentration of the corneal structure.

[0085] For example, the formula for calculating the energy gradient of the phase delay map is as follows: , in, For energy gradient, This is a phase delay map, where ROI represents the region of interest. For location, It is the square of the gradient magnitude.

[0086] Similarly, the energy gradient of the map along the fast axis direction will be expressed in the above equation. Change to That's all.

[0087] The directional consistency feature is characterized by directional consistency or directional variance, and is used to analyze the similarity of the directional vectors of effective observation units in the fast-axis directional map. Effective observation units can be, for example, effective pixels, superpixel units, or sector units within a Region of Interest (ROI).

[0088] Specifically, the step of calculating the corneal birefringence structure score based on the corneal birefringence structure characteristics includes: The corneal birefringence structure features are mapped to a birefringence structure score according to a preset scorer, wherein the scorer is: , in, Scoring the corneal birefringence structure, The preset total score, For activation function, For the preset weight vector, This represents the feature vector of the corneal birefringence structure. This is a bias term.

[0089] The total score is a configurable normalization constant and is not limited to a specific scoring system. In practice, a 100-point system, a 10-point system, or a 1-point system can be used before linear mapping. For example, if a 100-point system is used, the output Score ∈ [0, 100]; if a 10-point system is used, Score_10 = Score_100 / 10 can be directly set. The corneal birefringence structure feature vector can be obtained by arranging multiple corneal birefringence structure features in a preset order.

[0090] Specifically, the full-cycle management of the user's keratoconus based on the corneal birefringence structure score includes: A threshold table is used to map the corneal birefringence structure score into discrete levels; Full-cycle management of keratoconus is performed based on the discrete levels of users.

[0091] For example, the threshold table is as follows: in, This indicates that when the score is less than the first threshold At that time, the rating was G0, which usually represents "normal", "no risk" or "lowest level". This means when the score is greater than or equal to and less than At that time, the level was rated as G1, which means that it has entered the first abnormal or risky zone. This means when the score is greater than or equal to and less than At that time, the level was rated as G2, which means that the risk or severity has increased further. This means when the score is greater than or equal to At that time, the level was rated as G3, which typically represents "severe," "high risk," or "highest level." This threshold table is an example of a 4-level threshold table; of course, more or fewer discrete levels can be added depending on the actual situation, which is not limited here.

[0092] Specifically, the full-cycle management of the user's keratoconus based on the corneal birefringence structure score includes: At least one of the following trend analysis methods is used to calculate the user's keratoconus trend index based on the corneal birefringence structure score: sliding window interpolation method, regression slope method, and CUSUM method. When the keratoconus trend index exceeds the preset keratoconus trend index threshold, it is recommended that the user retest or verify it in conjunction with the topography index. The topography index is a corneal topography or thickness-related index that is cross-validated with the polarization birefringence results.

[0093] The sliding window interpolation method arranges data along a timeline. By setting a fixed-length time window, it slides forward along the timeline, discarding the oldest data and incorporating the newest. It then calculates the difference between the latest and earliest values ​​within the window, or the change in the average value within the window. In the sliding window interpolation method, the difference between the latest and earliest values ​​within the window, or the change in the average value within the window, can serve as an indicator of keratoconus trends. For example, the interpolation value can be defined as... For the current moment Corneal birefringence structure score Compared to a certain reference time point Corneal birefringence structure score difference .

[0094] The regression slope method uses a linear regression model to fit a trend line for all data points over a period of time, and the slope of this trend line is used as an indicator of keratoconus trend. Compared to single-point difference, the regression slope is better able to resist the influence of single measurement errors or outliers, reflecting the long-term overall trend.

[0095] The Cumulative Sum Control Chart (CUSUM) method calculates the cumulative sum of the differences between observed values ​​and target values ​​(or historical mean), using this cumulative sum as an indicator of keratoconus trend. In the very early stages of keratoconus, parameter changes may be very small, which conventional methods might consider within error limits. However, the CUSUM chart will show a clear unidirectional deviation trend, thus issuing an early warning. For example, the cumulative sum can be defined as follows: , in, For the current moment The accumulation of, For the previous moment The accumulation of, For the current moment Corneal birefringence structure score, For the previous moment The target value or expected mean. To allow for deviation.

[0096] Furthermore, the terrain indices include the intersection-over-union ratio and / or the Dice coefficient, and the method further includes: Import multimodal data, which includes terrain data and thickness data; Weakness mask is calculated based on the terrain data and thickness data, and polarization enhancement mask is calculated based on the phase delay map and / or fast axis orientation map; Calculate the cross-union ratio and / or Dice coefficient based on the weak region mask and the polarization enhancement region mask.

[0097] Intersection over Union (IoU) and Dice Coefficient are two core metrics used in image segmentation, computer vision, and medical image analysis to quantify the similarity or overlap between two regions (or sets). Their values ​​range from [0,1], where 0 indicates no overlap and 1 indicates complete overlap. IoU represents the proportion of the overlapping area between two regions (A and B, or in this application, the weak region mask and the polarization enhancement region mask) to the total coverage area. The specific calculation formula is as follows: , The Dice coefficient is used to represent the average proportion of overlap between two regions, and the specific calculation formula is as follows: .

[0098] In addition to these, topographic indicators may also include maximum keratometry (Kmax), posterior surface elevation, thinnest point thickness, thickness asymmetry, and other topographic / tomographic scanning indicators. Kmax is the value of the point on the corneal surface with the strongest refractive power (steepest point). Posterior surface elevation represents the height difference of the posterior surface of the cornea relative to a reference sphere or ellipsoid; a positive value indicates posterior bulging. Thinnest point thickness represents the value of the point with the smallest thickness within the entire corneal measurement area. Thickness asymmetry index is used to describe the non-uniformity of corneal thickness distribution.

[0099] Multimodal data refers to data from imaging devices based on different physical principles. For example, this application may include topographic data and thickness data. Topographic data reflects the curvature and height distribution of the corneal surface and is the gold standard morphological indicator for diagnosing keratoconus. Thickness data refers to the thickness distribution map of various points on the cornea. A typical feature of keratoconus is localized thinning. Topographic maps may miss subclinical diagnoses, while polarization maps may be affected by noise. Multimodal complementarity can overcome the limitations of single-modality data.

[0100] Specifically, based on topographic and thickness data, and using traditional diagnostic criteria for keratoconus, a binary image can be obtained, marking areas where anatomical deformation or thinning has occurred—the thin area mask. Based on phase retardation maps and / or fast axis orientation maps, algorithms identify areas with birefringence anomalies or disordered fiber arrangement, resulting in a binary image that marks areas with biomechanical or microstructural anomalies—the polarization enhancement area mask.

[0101] Specifically, the review incorporating terrain indicators includes: The risk quantification result is calculated based on the keratoconus trend index and its corresponding weight, the topography index and its corresponding weight, and the confidence level of the risk quantification result is output.

[0102] For example, the formula for calculating the risk quantification result is as follows: , in, To quantify the results of risk, The score corresponding to the keratoconus trend index. The weights corresponding to the keratoconus trend index, The scores corresponding to the terrain indicators. The weights corresponding to the terrain indicators.

[0103] The confidence level indicates the reliability of the risk result itself. It can be calculated based on factors such as data integrity, quality control compliance, intermodal consistency, and historical stability. For example, it can be calculated using the following formula: , in, For confidence level, The activation function is Sigmoid. , , , These are weight coefficients learned from training data. Indicates the basic bias term. This indicates a penalty for missing data. This represents the fitting residual / noise penalty term. This indicates a consistency reward item.

[0104] Figure 3 A schematic diagram of a corneal phase retardation map and fast axis orientation map acquisition device according to an embodiment of this application is shown. The device includes: The polarization measurement unit 301 is used to input a preset polarization state to the metasurface polarization analyzer to obtain polarization measurement data output by the metasurface polarization analyzer. The polarization state matrix parameter solving unit 302 is used to solve the polarization state matrix parameters based on the polarization measurement data. The map parameter determination unit 303 is used to decompose the polarization state matrix parameters to obtain the phase delay map and fast axis direction map of the cornea.

[0105] Figure 4 The diagram illustrates the structure of a computer device according to an embodiment of this application, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the functions of the computer system for obtaining the corneal phase delay map and fast axis direction map in any of the above embodiments.

[0106] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a computer, causes the computer to perform the functions of the computer system of the corneal phase delay map and fast axis direction map acquisition method in any of the above embodiments.

[0107] This application also provides a computer program product containing instructions that, when executed by a computer, cause the computer to perform the functions of the computer system of the corneal phase delay map and fast axis direction map acquisition method in any of the above embodiments.

[0108] It is understood that the specific examples in this application are only intended to help those skilled in the art better understand the implementation methods of this application, and are not intended to limit the scope of the invention.

[0109] It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not limit the implementation process of the embodiments of this application in any way.

[0110] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and the implementation methods in this application are not limited in this respect.

[0111] Unless otherwise stated, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0112] It is understood that the processor in the embodiments of this application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiments can be completed by the integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0113] It is understood that the memory in the embodiments of this application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Specifically, non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM). It should be noted that the memory in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0114] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0115] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the aforementioned method implementations, and will not be repeated here.

[0116] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0117] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0118] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0119] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0120] The above are merely specific embodiments of this application, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A method of acquiring a phase retardation map and a fast axis direction map of a cornea, characterized by, The method includes: The preset polarization state is input into the metasurface polarization analyzer to obtain the polarization measurement data output by the metasurface polarization analyzer; Solve for the polarization state matrix parameters based on the polarization measurement data; By decomposing the polarization state matrix parameters, a phase delay map and a fast axis orientation map of the cornea are obtained.

2. The method according to claim 1, characterized in that, The polarization state matrix parameters include Stokes parameters or Mueller matrices, and the process of solving for the polarization state matrix parameters based on the polarization measurement data includes: If the preset polarization state is a single fixed state, then the Stokes parameters are solved based on the polarization measurement data and the weighted least squares method. If the number of preset polarization states is less than the maximum number of polarization analysis channels formed by the metasurface polarization analyzer within the same exposure window, then the constrained Mueller matrix is ​​solved based on the polarization measurement data and constrained optimization. If the number of preset polarization states is equal to the maximum number of polarization analysis channels formed by the metasurface polarization analyzer within the same exposure window, then the complete Mueller matrix is ​​solved by standard decomposition based on the polarization measurement data. The restricted Mueller matrix has fewer independent parameters than the complete Mueller matrix.

3. The method according to claim 2, characterized in that, The formula for determining the Stokes parameter is: ， in, For Stokes parameters, The analysis matrix obtained by calibrating the metasurface polarization analyzer. For the preset weight matrix, This is polarization measurement data.

4. The method according to claim 2, characterized in that, The formula for determining the Mueller matrix is: ， in, For Muller matrix, The Mueller matrix for the optimal solution. For the first The polarization state at the th ... Observations from each polarization analysis channel For the first The vector corresponding to each polarization analysis channel For the first One polarization state, This refers to the prior physical constraints or penalties imposed on the Mueller matrix.

5. The method according to claim 1, characterized in that, The method further includes: The reliability of the phase delay map and the fast axis direction map is determined according to the quality control and rejection or degradation mechanism; When the reliability of the phase delay map and the fast axis direction map is determined to be satisfactory, the phase delay map and the fast axis direction map are output.

6. The method according to claim 1, characterized in that, The determination of the reliability of the phase delay map and the fast axis direction map based on the quality control and rejection or degradation mechanism includes: The polarization quality assessment parameters are obtained, including image quality parameters, region parameters, basic parameters, and advanced parameters. The image quality parameters are parameters extracted based on the statistical features of the original light intensity image. The region parameters are statistical quantities describing the consistency of the spatial distribution of the image. The basic parameters are polarization state description quantities obtained by directly solving the Stokes parameters or Mueller matrix. The advanced parameters are physical quantities that need to be obtained by performing complex mathematical inversion calculations on the basic parameters. The system sequentially performs a severe defect determination based on the image quality parameters, a region validity determination based on the region parameters, and a parameter reliability determination based on the basic and advanced parameters.

7. The method according to claim 1, characterized in that, The method further includes: Based on the phase delay map and the fast axis orientation map, corneal birefringence structural features are extracted from the region of interest. The corneal birefringence structural features include phase delay statistical features, gradient energy features, and orientation consistency features. Calculate the corneal birefringence structure score based on the corneal birefringence structure characteristics; The user's keratoconus is managed throughout its entire lifecycle based on the corneal birefringence structure score.

8. A device for acquiring a phase delay map and a fast axis orientation map of the cornea, characterized in that, The device includes: A polarization measurement unit is used to input a preset polarization state to a metasurface polarization analyzer to obtain polarization measurement data output by the metasurface polarization analyzer. A polarization state matrix parameter solving unit is used to solve for polarization state matrix parameters based on the polarization measurement data; The map parameter determination unit is used to decompose the polarization state matrix parameters to obtain the phase delay map and fast axis direction map of the cornea.

9. An electronic device, characterized in that, include: Processor and memory; The processor is connected to a memory, wherein the memory is used to store a computer program, and the processor is used to invoke the computer program to perform the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions that, when executed by a processor, perform the method as described in any one of claims 1-7.

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