Tear film data processing method, ophthalmic medical device, and computer readable medium

Abstract

The application provides a tear film data processing method, an ophthalmic medical device and a computer readable medium. The method first projects a light reflection point on the cornea by using a biometer, acquires light reflection point data, and calculates a tangential slope corresponding to each light reflection point. A tear film surface is obtained based on Zernike polynomial fitting. Further, a tear film height map changing over time can be obtained according to the changes of the tear film surfaces of multiple frames, so that the dynamic change state of the tear film during continuous shooting can be clearly acquired.

Description

Technical Field

[0001] This application relates to the field of medical imaging technology, and in particular to the application of a tear film detection method in ophthalmic examination. Background Technology

[0002] The tear film is a thin liquid film covering the surface of the eyeball, and its condition plays a crucial role in eye health. The cornea and tear film are an inseparable functional unit, together constituting the microenvironment of the ocular surface. By measuring the tear film, various information about the cornea can be obtained. Furthermore, the stability of the tear film directly relates to visual quality and the overall health of the eye. Summary of the Invention

[0003] The first aspect of this application proposes a tear film detection method, comprising: Collect data on the light-reflecting points of the tear film; Based on the tear film light-reflection point data, obtain the tangential slope of the tear film position corresponding to each light-reflection point; The tear film surface is obtained by fitting Zernike polynomials based on the tangential slope of the tear film position corresponding to the reflection point.

[0004] According to some embodiments, including: Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by Zernike polynomial fitting, including: The tear film surface to be fitted is described by Zernike polynomials. , Where the parameter j is the number of terms in the Zernike polynomial, Let be the coefficient of the j-th term of the polynomial. Let j be the j-th term of the Zernike polynomial; Construct the objective function O b = - ; in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. A matrix representation of the tangential slope at the tear film position corresponding to a specific light-reflecting point obtained from the light-reflecting point data; By using the objective function O b Minimize or minimize to obtain the fitted tear film surface.

[0005] According to some embodiments, including: Based on the first penalty term, an objective function is constructed to fit the tear film surface, that is, to construct the objective function O. b = - ; in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. This is a matrix representation of the tangential slope at the tear film position corresponding to a specific light-reflecting point obtained from light-reflecting point data. Represents the tear film surface to be fitted. For radius The first derivative in radius The value of p1 is the coefficient of the first penalty term.

[0006] By using the objective function O b Minimize or minimize to obtain the fitted tear film surface.

[0007] According to some embodiments, including: The acquired tear film light-reflection point data includes multiple frames of light-reflection point images; Obtain the fitted baseline tear film surface and the tear film surface fitted to each frame of light-reflecting point image; By subtracting each tear film surface from the reference tear film surface, a tear film height map that changes over time is obtained.

[0008] According to some embodiments, including: The collected light spot data includes one or more light spot images, each light spot image includes three rings of light spots, and each ring contains 12 light spots.

[0009] According to some embodiments, including: The center of the light-reflecting point is obtained based on the position of each light-reflecting point. The axial radius of curvature of the tear film position corresponding to each light-reflecting point is obtained based on the distance between the center of the light-reflecting point and each light-reflecting point. The tangential slope of the tear film position corresponding to each light-reflecting point is then obtained.

[0010] According to some embodiments, including: The acquired tear film light-reflection point data includes multiple frames of light-reflection point images; Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by Zernike polynomial fitting, including: Select the light-reflecting point image of the frame corresponding to the reference tear film surface, and obtain the fitted reference tear film surface based on the Zernike polynomial; Based on the fitted baseline tear film surface, the fitted tear film surfaces corresponding to other frame light-reflection point images are further obtained, wherein the objective function O is used to... b The objective function, which minimizes or reduces the value of the fitted tear film surface, also includes a second penalty term. or ,in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. The radius of the reference tear film surface to be fitted A matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position; Here is the coefficient matrix of the Zernike polynomial to be fitted. It is the coefficient matrix of each term of the Zernike polynomial of the fitted reference surface.

[0011] According to some embodiments, including: The acquired tear film light-reflection point data includes multiple frames of light-reflection point images; Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by Zernike polynomial fitting, including: The reference tear film surface is obtained by selecting the light-reflecting point image of the frame corresponding to the reference tear film surface and fitting it based on Zernike polynomials. Based on the fitted baseline tear film surface, the fitted tear film surfaces corresponding to other frame image points are further obtained; wherein, the tear film surface to be fitted is represented by the baseline tear film surface represented by Zernike polynomial and the sum of B-spline functions and fitted.

[0012] The second aspect of this application discloses an ophthalmic medical device, comprising: Ring light source Imaging system: can acquire images of light-reflecting points of corneal reflective signals; A processor for executing any of the methods described in the first aspect above.

[0013] A third aspect of this application provides a computer-readable medium storing instructions that, when executed, implement any of the methods in the first aspect. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This diagram illustrates an example of a tear film fluorescence dot data processing method according to an embodiment of this application. Figure 2 This is a schematic diagram illustrating an example of a reflective dot image according to an embodiment of this application; Figure 3 A schematic diagram illustrating an example of a method for obtaining the curvature of the tear film according to an embodiment of this application is shown. Figure 4-1 This is a schematic diagram illustrating an example of a tear film height map according to an embodiment of this application; Figure 4-2 This is a schematic diagram illustrating an example of a tear film height map according to an embodiment of this application; Figure 5 The diagram illustrates an example of a fitting method for obtaining the tear film surface according to an embodiment of this application. Detailed Implementation

[0016] This application provides a method for processing tear film fluorescence spot data, such as... Figure 1 As shown, the method includes the following steps: S1: Collect light-reflecting point data of the tear film; About the tear film The tear film is an extremely thin liquid layer covering the anterior surface of the cornea. The cornea and tear film are an inseparable functional whole, together constituting the microenvironment of the ocular surface. The tear film is not static; physiological activities or phenomena such as blinking, tear secretion, and tear film evaporation all lead to changes in its morphology. Analysis of the tear film can be used to analyze changes in the tear film itself, as well as the condition of the anterior corneal surface. For example, when the tear film is stable, its morphology can be used to obtain the morphology of the anterior corneal surface. When the tear film is not considered or is assumed to be stable, the light reflex data collected from the tear film can be considered consistent with the light reflex data collected from the cornea. On the other hand, analysis of the tear film surface can further reveal changes in the tear film, such as the tear film breakup process, thus aiding in ocular diagnosis. In general, collecting tear film data can also be described as collecting corneal data.

[0017] Generally, images of the light-reflecting points can be acquired using ophthalmic equipment to obtain data on the positional relationships of these points. For example, see [link to example]. Figure 2 The tear film's light-reflecting points can be obtained using a biometric instrument. The biometric instrument consists of a ring-shaped light source array and an image acquisition device. The light emitted from the ring-shaped light source array is reflected on the corneal surface, and the reflected light signal is acquired by the image acquisition device, thus obtaining an image containing the light-reflecting points. These points appear as bright spots corresponding to the light source. By analyzing the position, shape, and distribution of these light-reflecting points, the optical morphology of the tear film surface can be obtained.

[0018] Preferably, the collected light-reflecting point data includes one or more light-reflecting point images, each light-reflecting point image includes three rings of light-reflecting points, and each ring contains 12 light-reflecting points.

[0019] For example, an image of the tear film's light reflection can be obtained by illuminating the cornea with a ring light source array, wherein the ring light source is arranged in concentric rings. The ring light source array can be near-infrared LEDs. As a preferred embodiment, the ring light source array can be composed of three concentric rings, each ring consisting of 12 equally spaced near-infrared LEDs. The ring light source array can also be composed of other combinations of light sources with different numbers of rings.

[0020] The light-reflecting point data includes images of light-reflecting points containing their positions and morphological relationships. This information can also be obtained through other means. For example, one or more light-reflecting point images can be collected as needed to evaluate the morphology of the tear film or cornea. Multiple light-reflecting point images can also be multiple consecutive frames of light-reflecting point images over a period of time to evaluate changes in the morphology of the tear film or cornea, or specific frames can be selected to evaluate the morphology of the tear film or cornea. Generally, S2, based on the tear film reflection point data, obtain the tangential slope of the tear film position corresponding to each reflection point; Generally, the cornea is spherical or nearly spherical. When light strikes the corneal surface, it is reflected onto the anterior surface. The distribution and direction of these reflected lights are closely related to the curvature of the cornea. In this application, the reflection point obtained through a ring-shaped light source can reflect the optical parameters or lens shape of a certain area or point on the tear film surface. Utilizing the reflective characteristics of the corneal surface, based on the position information of the reflection point on the tear film, combined with light source information, the distance between the light source and the tear film, and the optical parameters of the device, the tangential slope of the corresponding tear film position can be calculated. The tangential slope represents the degree of inclination of the tangent to the meridian of the tear film surface at that position. Generally, the tear film position corresponding to the reflection point can also be described as the corneal position corresponding to the reflection point.

[0021] It should be noted that the distance on the image (pixel distance) first needs to be converted into the actual physical distance. The actual physical distance still needs to be calculated and parameterized to obtain information such as the axial radius of curvature and tangential slope at the corresponding tear film position.

[0022] Reference plane and coordinates describing the tear film surface The tear film surface can be described by the height of different points on the tear film surface relative to a reference plane. The reference plane is a plane perpendicular to the optical axis of the measuring instrument and tangent to the cornea / tear film apex. Different points can be described as the coordinates of the points on the tear film surface projected onto the reference plane along the optical axis of the measuring instrument, based on the tear film apex (origin). Alternatively, if obtaining the absolute height value is not considered, a plane parallel to the aforementioned reference plane can also be used as the descriptive reference. Different reference planes describe the corneal coordinate positions (…). With W( ) remaining constant, differences in the absolute value of the height do not affect the description of the overall shape of the surface. For example, through W( Describe the surface to be fitted, where the origin is the vertex of the cornea / tear film. This represents the radius of the point on the tear film surface projected onto the reference plane along the instrument's optical axis, from the origin. This represents the rotation angle of a point on the tear film surface projected onto a reference plane relative to the origin within that reference plane. This coordinate system can describe different... The tear film height or other parameters at a given location. A meridian can be understood as the corneal curvature (or the corresponding tear film curvature) at a fixed point. The intercepted line, the meridian of the tear film surface, is coplanar with the optical axis of the measuring instrument, and this surface is perpendicular to the reference plane. In this application, the value of a point on the surface to be fitted or fitted is described by its height relative to the reference plane, and the coordinates of a point on the surface to be fitted or fitted are described by its projection position relative to the reference plane. The coordinate position can be described by transformation using a polar coordinate system or a Cartesian coordinate system.

[0023] Points on the tear film surface corresponding to light-reflecting points can be mapped or transformed based on device parameters. Specifically, based on the device's optical parameters, distance from the tear film, and coordinates of the light source, the coordinates of a point on the corneal / tear film surface corresponding to different light sources can be obtained. In other words, through light-reflecting point data or image data, information such as the height, curvature, and slope of a point on the corresponding tear film surface can be obtained.

[0024] Optionally, the center of each reflector point can be obtained based on its location, and the axial radius of curvature of the tear film corresponding to each reflector point can be obtained based on the distance between the center of the reflector point and each reflector point. Further, the tangential slope of the tear film corresponding to each reflector point can be obtained. For example, the physical coordinates of the virtual image point of the light source (with a one-to-one correspondence between the light source and the reflector point) within the tear film can be used as the coordinates of the reflector point at its corresponding tear film position. Then, the tangential slope of the tear film corresponding to each reflector point can be obtained based on the axial radius of curvature.

[0025] For example, for each image or frame of a reflective point, the position information of the reflective point is extracted using an image processing algorithm. Then, a fitting algorithm (such as the least squares method) is used to fit the center point of the ring containing different reflective points. The position of this center point is the center position of the reflective point. By calculating the distance from each reflective point to its center position, the coordinates of the virtual image point within the tear film corresponding to that reflective point, as well as information such as the curvature, tangential slope, and height of the tear film, can be obtained.

[0026] S3. Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by fitting with Zernike polynomials.

[0027] Understandably, the tangential slope of a reflective point, or the tangential slope of a point on the tear film surface corresponding to that reflective point, is a quantitative expression of the tear film's surface morphology. The tangential slope of each reflective point reflects the inclination of the meridian at that corresponding position on the tear film. Since the tear film is a continuous surface, by using a large amount of tangential slope data from reflective points and fitting it with a suitable mathematical model, the overall morphology of the tear film can be reconstructed, thus obtaining a mathematical expression describing the entire tear film surface.

[0028] The tear film surface to be fitted can be represented by Zernike polynomials. , that is

[0029] The terms of the Zernike polynomial are:

[0030]

[0031] Where j is the number of terms in the Zernike polynomial, m and n are the parameters of the Zernike polynomial, and j, n, and m are all non-negative integers. Let be the coefficient of the j-th term of the polynomial. The radius (or simply radius) represents the coordinates of the point on the tear film surface projected onto the reference plane from the origin. An angle is the angular coordinate of a point on the tear film surface projected onto a reference plane relative to the origin.

[0032] A specific number of terms can be selected to fit the tear film surface, thus obtaining the surface to be fitted under different numbers of terms. Through fitting, the coefficients of each term in the Zernike polynomial to be fitted are obtained. The value of is used to obtain the fitted tear film surface.

[0033] Tear film surface to be fitted It can also be represented in matrix form, that is: A j ×Z j Among them, A j Let Z be the coefficient matrix (1×j) of the Zernike polynomial. j This is the matrix representation of the Zernike polynomial (j×1).

[0034] For any tear film surface Its effect on The first derivative can be used to represent a specific meridian (i.e., a specific...) The slope at different points on the tear film surface (in the case of a certain value), that is, the tangential slope at different positions on the tear film surface. This is achieved by obtaining the Zernike polynomial pair. The first derivative form is used to fit the tangential slope surface of the tear film, thereby obtaining the fitted tear film surface.

[0035] Tear film curvature For radius The first derivative is in the form of: ,

[0036]

[0037] Thus, the tear film surface is obtained. For radius The first derivative is used to calculate the coordinates of the tear film position corresponding to each light-reflecting point, based on the tangential slope of the tear film surface at different light-reflecting points. The coefficients of each term of the surface to be fitted, expressed in Zernike polynomials, are obtained by combining the values ​​of the tangential slope and the tangential slope. This means obtaining the fitted tear film surface.

[0038] Specifically, this can be achieved by constructing an objective function O. b The fitted tear film surface is obtained by minimizing or minimizing the objective function. For example, the objective function O is constructed as follows: b = - ;in, The radius of the surface to be fitted The matrix representation of the value of the first derivative at each reflective point corresponding to the tear film position (1×t, where t is the number of reflective points). This is a matrix representation of the tangential slope at the tear film position corresponding to a specific light-reflecting point obtained from light-reflecting point data. The notation for norm calculation can be provided, using the 1-norm, 2-norm, or Frobenius norm. This is achieved by using the objective function O... b Minimizing or minimizing the Zernike polynomial yields the coefficients of each term, which in turn gives the fitted tear film surface.

[0039] As a preferred approach, to achieve a better fit, considering the potential error caused by the fitting vertex not coinciding with the corneal vertex in the slope plane space, a first penalty term can be added to the constructed objective function to obtain a better fit. That is, construct an objective function O that includes the first penalty term. b = - ,in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. This is a matrix representation of the tangential slope at the tear film position corresponding to a specific light-reflecting point obtained from light-reflecting point data. Represents the tear film surface to be fitted. For radius The first derivative in radius The value at time, p1 is the coefficient of the first penalty term; " is the symbol for norm calculation, which can be calculated using 1-norm, 2-norm, or Frobenius norm. A larger value can be set to ensure that the fitted tear film vertex coincides with or is as close as possible to the corneal vertex, thereby improving fitting accuracy. For example, setting... =1000.

[0040] One or more light-reflecting point images can be acquired to obtain light-reflecting point data. This data can be processed or filtered. For all or part of the light-reflecting point images, the corresponding tear film surface is fitted. Alternatively, multiple frames of light-reflecting point images can be acquired, and the corresponding tear film surface is fitted based on each frame or a portion of the light-reflecting point images.

[0041] When multiple frames of light-reflecting point images are acquired, that is, multiple light-reflecting point images that change over time are obtained, the changes in the tear film surface over time can be further analyzed. By selecting one light-reflecting point image as the reference light-reflecting point image, the corresponding reference tear film surface is obtained by fitting it. The tear film surface obtained from each frame of light-reflecting point images is subtracted from the reference tear film surface to obtain multiple tear film height maps that change over time.

[0042] The reference image can be selected from images immediately after blinking, images at the moment of tear film breakup, or images of a stable tear film. By selecting a reference surface, it is easier to analyze the changes in the tear film surface.

[0043] See Figure 3 To evaluate changes in the tear film, multiple frames of light-reflecting point data can be collected to obtain a multi-frame fitted tear film surface, which facilitates the analysis of changes in the tear film surface over time.

[0044] Step S11: Collect the light-reflecting point data of the tear film, wherein the collected light-reflecting point data of the tear film includes the collection of multiple frames of light-reflecting point images; Step S21: Based on the tear film's light-reflecting point data, obtain the tangential slope of the tear film position corresponding to each light-reflecting point in each frame; Step S31: Select the light-reflecting point data of the frame corresponding to the reference tear film surface to obtain the fitted reference tear film surface; The acquisition of the reflective point image, the calculation of the tangential slope, and the acquisition of the fitted reference tear film surface can be achieved by referring to the method described in the above embodiments.

[0045] Step S32: Based on the fitted baseline tear film surface, further obtain the fitted tear film surfaces corresponding to other frame image points, wherein the objective function O is used to... b Minimize or minimize to obtain the fitted tear film surface; Due to the localized nature of tear film breakup, a second penalty term can be added to better fit the tear film surface, resulting in a smaller overall variation between the fitted surface and the reference surface across different frames. The second penalty term describes the difference between the tear film surface fitted from the image point data of each frame and the reference tear film surface.

[0046] For example, with a first penalty term, the objective function is constructed as follows: O b =

[0047] in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. The radius of the reference tear film surface for fitting A matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position; Represents the radius of the tear film surface to be fitted. The first derivative in radius The value at time.

[0048] “ " is the symbol for norm calculation, which can be calculated using 1-norm, 2-norm, or Frobenius norm.

[0049] The fitted tear film surface is obtained by minimizing or minimizing the objective function.

[0050] Alternatively, the above objective function can also be expressed as: O b = , in, Here is the coefficient matrix of the Zernike polynomial to be fitted. It is the coefficient matrix of each term of the Zernike polynomial of the fitted reference surface.

[0051] To facilitate the analysis of the height changes of the tear film surface, an optional step S33 is also provided: by subtracting each tear film surface from the reference tear film surface, a tear film height map that changes over time is obtained.

[0052] Figure 4-1 The height difference between the tear film surface in a given frame and the reference tear film surface is obtained by fitting an objective function with only the first penalty term, and Figure 4-2 The height difference between the tear film surface and the reference tear film surface in a given frame, obtained by fitting an objective function with first and second penalty terms, is presented. It can be seen that both fitting methods can fit the changes in the upper left region of the cornea well, while the height change map obtained by adding the second penalty term shows smaller overall changes and smoother non-changing areas.

[0053] See Figure 5 To evaluate changes in the tear film, another method for fitting the tear film surface was also disclosed. The specific steps are as follows: Step S101: Collect the light-reflecting point data of the tear film, wherein the collected light-reflecting point data of the tear film includes the collection of multiple frames of light-reflecting point images; Step S201: Based on the tear film's light-reflecting point data, obtain the tangential slope of the tear film position corresponding to each light-reflecting point in each frame; Step S301: Select the light-reflecting point image of the frame corresponding to the reference tear film surface to obtain the fitted reference tear film surface; The acquisition of the reflective point image, the calculation of the tangential slope, and the acquisition of the fitted reference tear film surface can be achieved by referring to the method described in the above embodiments.

[0054] Step S302: Based on the fitted reference tear film surface, further obtain the fitted tear film surfaces corresponding to the image points of other frames; wherein, the tear film surface to be fitted is represented by the reference tear film surface represented by Zernike polynomial and the sum of B-spline functions and fitted. The applicant found that low-order Zernike surface fitting has poor local fitting ability. Therefore, they proposed fitting the tear film surface together with Zernike surfaces and B-splines. Specifically, Zernike surfaces are used to fit the entire surface, while B-splines are used to fit the local tear film rupture process.

[0055] Specifically, for any frame of light-reflecting data, its fitted tear film surface F It can be represented as: F

[0056] in, It is a baseline tear film surface fitted by Zernike polynomials (based on a baseline photon image). This is the spline function part to be fitted. This can be represented as the spline basis function is Multiple combinations, that is = .

[0057] spline function Expressed in matrix form as follows: =A i × , Where A i The coefficient matrix of each term in the spline function This is the matrix representation of the spline basis functions.

[0058] Furthermore, an objective function can be constructed: O b =

[0059] in, For the spline function to be fitted with respect to the radius The matrix representation of the derivative values ​​at each reflective point corresponding to the tear film position; The reference tear film surface to be fitted with respect to the radius The matrix representation of the derivative values ​​at each reflective point corresponding to the tear film position; This is a matrix representation of the values ​​of the spline function to be fitted at each reflective point corresponding to the tear film position; " is the notation for norm calculation, which can be calculated using 1-norm, 2-norm, or Frobenius norm; the fitted tear film surface is obtained by minimizing or minimizing the objective function.

[0060] Alternatively, the above objective function can also be expressed as: O b =

[0061] in, It is the coefficient matrix of the spline function to be fitted.

[0062] Preferably, the spline function mentioned above is a quadratic B-spline function.

[0063] To facilitate the analysis of the height changes of the tear film surface, an optional step S303 is also provided: by subtracting each tear film surface from the reference tear film surface, a tear film height map that changes over time is obtained.

[0064] By fitting the entire surface using Zernike and then using B-spline fitting to fit the local tear film breakup process, the changes in the tear film breakup process can be more effectively and accurately fitted.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0067] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

Claims

1. A tear film data processing method, characterized in that, include: S1: Collect tear film light-reflection point data; S2: Based on the tear film reflection point data, obtain the tangential slope of the tear film position corresponding to each reflection point; S3: Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by fitting with Zernike polynomials.

2. The method according to claim 1, characterized in that, include: Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by Zernike polynomial fitting, including: The tear film surface to be fitted is described by Zernike polynomials. , Where the parameter j is the number of terms in the Zernike polynomial, Let be the coefficient of the j-th term of the polynomial. Let j be the j-th term of the Zernike polynomial; Construct the objective function O b = - ; in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. A matrix representation of the tangential slope at the tear film position corresponding to a specific light-reflecting point obtained from the light-reflecting point data; By using the objective function O b Minimize or minimize to obtain the fitted tear film surface.

3. The method according to claim 2, characterized in that, include: Based on the first penalty term, an objective function is constructed to fit the tear film surface, that is, to construct the objective function O. b = - ; in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. This is a matrix representation of the tangential slope at the tear film position corresponding to a specific light-reflecting point obtained from light-reflecting point data. Represents the tear film surface to be fitted. For radius The first derivative in radius The value of p1 is the coefficient of the first penalty term. By using the objective function O b Minimize or minimize to obtain the fitted tear film surface.

4. The method according to any one of claims 1-3, characterized in that, include: The acquired tear film light-reflection point data includes multiple frames of light-reflection point images; Obtain the fitted baseline tear film surface and the tear film surface fitted to each frame of light-reflecting point image; By subtracting each tear film surface from the reference tear film surface, a tear film height map that changes over time is obtained.

5. The method according to any one of claims 1-4, characterized in that, include: The collected light spot data includes one or more light spot images, each light spot image includes three rings of light spots, and each ring contains 12 light spots.

6. The method according to any one of claims 1-3, characterized in that, include: The center of the light-reflecting point is obtained based on the position of each light-reflecting point. The axial radius of curvature of the tear film position corresponding to each light-reflecting point is obtained based on the distance between the center of the light-reflecting point and each light-reflecting point. The tangential slope of the tear film position corresponding to each light-reflecting point is further obtained.

7. The method according to claim 2 or 3, characterized in that, include: The acquired tear film light-reflection point data includes multiple frames of light-reflection point images; Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by Zernike polynomial fitting, including: Select the light-reflecting point image of the frame corresponding to the reference tear film surface, and obtain the fitted reference tear film surface based on the Zernike polynomial; Based on the fitted baseline tear film surface, the fitted tear film surfaces corresponding to other frame light-reflection point images are further obtained, wherein the objective function O is used to... b The objective function, which minimizes or reduces the value of the fitted tear film surface, also includes a second penalty term. or ,in, The radius of the tear film surface to be fitted The matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position. The radius of the reference tear film surface to be fitted A matrix representation of the values ​​of the first derivative at each reflective point corresponding to the tear film position; Here is the coefficient matrix of the Zernike polynomial to be fitted. It is the coefficient matrix of each term of the Zernike polynomial of the fitted reference surface.

8. The method according to claim 2 or 3, characterized in that, include: The acquired tear film light-reflection point data includes multiple frames of light-reflection point images; Based on the tangential slope of the tear film position corresponding to the reflection point, the tear film surface is obtained by Zernike polynomial fitting, including: The reference tear film surface is obtained by selecting the light-reflecting point image of the frame corresponding to the reference tear film surface and fitting it based on Zernike polynomials. Based on the fitted baseline tear film surface, the fitted tear film surfaces corresponding to other frame image points are further obtained; wherein, the tear film surface to be fitted is represented by the baseline tear film surface represented by Zernike polynomial and the sum of B-spline functions and fitted.

9. An ophthalmic medical device, characterized in that: Ring light source Imaging system: can acquire images of light-reflecting points of corneal reflective signals; A processor for performing the method described in any one of claims 1-8.

10. A computer-readable medium, characterized in that: The computer-readable medium stores instructions that, when executed, implement the method of any one of claims 1 to 8.

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