A method, system and apparatus for analyzing corneal biomechanical properties

Abstract

The application discloses an analysis method, system and device for corneal biomechanical characteristics, and relates to the field of biomechanics. A driving device is used to apply pressure to the cornea while obtaining video data of the deformation of the cornea caused by external force; an unsupervised algorithm is used to extract the corneal contour in any frame of the video data; the pixel points on the corneal contour are used as reference points for biomechanical characteristic analysis; according to the time sequence of any frame of image, the offset of the reference points of any frame of image relative to the initial position of the cornea is calculated to obtain the variation of the absolute displacement of all reference points on any frame of image; the time sequence is expanded to a third-dimensional coordinate on the basis of the two-dimensional pixel coordinates of the image to establish a three-dimensional coordinate system; the geometric structure of the corneal deformation amplitude is obtained according to the variation and the three-dimensional coordinate system; and the geometric structure is used to represent the corneal biomechanical characteristics. The application realizes the measurement of the corneal biomechanical characteristics in all directions.

Description

Technical Field

[0001] This invention relates to the field of biomechanics, and in particular to a method, system and device for analyzing the biomechanical properties of the cornea. Background Technology

[0002] The biomechanical properties of the cornea play a crucial role in the development and progression of many corneal diseases, as well as in the long-term stability and safety of corneal refractive surgery. Therefore, the biomechanical properties of the cornea have gradually become a hot research topic.

[0003] However, the biomechanical properties of the cornea are not yet fully understood, partly due to the difficulty in obtaining reliable in vivo corneal biomechanical data. The Oral Response Analyzer (ORA) was the first device globally to measure in vivo corneal biomechanics, providing corneal hysteresis and corneal resistance factor. The Corvis ST Visualized Corneal Biomechanics Analyzer can acquire multiple dynamic corneal response parameters, as well as internally calculated comprehensive parameters reflecting corneal biomechanical properties.

[0004] The biomechanical properties currently calculated describe parameters of the cornea at specific times and locations, and these parameters are correlated with each other, thus failing to fully reflect the true biomechanical properties of the cornea. Furthermore, these parameters reflect the overall deformation of the cornea, but cannot provide information on local corneal mechanical changes, let alone reflect the mechanical changes at specific points or regions. Summary of the Invention

[0005] The purpose of this invention is to provide a method, system, and device for analyzing corneal biomechanical properties, enabling the measurement of corneal biomechanical properties at any time, any location, and from all angles, thus providing a more comprehensive and accurate assessment of corneal biomechanical properties.

[0006] To achieve the above objectives, embodiments of the present invention provide the following solutions:

[0007] A method for analyzing the biomechanical properties of the cornea, comprising:

[0008] While applying pressure to the cornea using a driving device, video data of the cornea deforming under external force is acquired;

[0009] An unsupervised algorithm is used to extract the corneal contour from any frame of the video data; the pixels on the corneal contour are used as reference points for biomechanical property analysis.

[0010] Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image.

[0011] Based on the two-dimensional pixel coordinates of the image, the time series is extended to a third-dimensional coordinate system to establish a three-dimensional coordinate system;

[0012] The geometric structure of the corneal deformation amplitude is obtained based on the change amount and the three-dimensional coordinate system; the geometric structure is used to characterize the biomechanical properties of the cornea.

[0013] Optionally, based on the time series of any frame image, the offset of the reference point of any frame image relative to the initial position of the cornea is calculated, resulting in the change in the absolute spatial displacement of all reference points on any frame image, specifically including:

[0014] The time t1 for acquiring the first frame image, and the offset Y1 of the reference point of the first frame image relative to the initial position of the cornea;

[0015] The time t for acquiring the (n+1)th frame image n+1 The offset Y of the reference point of the (n+1)th frame image relative to the initial position of the cornea n+1 ;

[0016] Based on the time t1 and time t n+1 Offset Y1 and offset Y n+1 The change was obtained.

[0017] Optionally, the change includes: velocity change and displacement change.

[0018] Optionally, the formula for calculating the change in velocity is:

[0019]

[0020] Optionally, the formula for calculating the displacement change is:

[0021] x n+1 =Y n+1 -Y1.

[0022] Optionally, the Z-axis of the three-dimensional coordinate system represents the time series of all images, the X-axis represents the location of the reference point in any frame of the image, and the Y-axis represents the offset of the reference point in any frame of the image relative to the initial position of the cornea.

[0023] Optionally, the geometry is a three-dimensional model.

[0024] A system for analyzing the biomechanical properties of the cornea, comprising:

[0025] A drive mechanism used to apply pressure to the cornea;

[0026] The data acquisition module is used to acquire video data of corneal deformation caused by external force when pressure is applied to the cornea;

[0027] A corneal contour extraction module, connected to the data acquisition module, is used to extract the corneal contour from any frame of the video data using an unsupervised algorithm; the pixels on the corneal contour serve as reference points for biomechanical characteristic analysis.

[0028] The change calculation module, connected to the corneal contour extraction module, is used for:

[0029] Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image.

[0030] Based on the two-dimensional pixel coordinates of the image, the time series is extended to a third-dimensional coordinate system to establish a three-dimensional coordinate system;

[0031] A three-dimensional model construction module, connected to the change calculation module, is used to obtain the geometric structure of the corneal deformation amplitude based on the change and the three-dimensional coordinate system; the geometric structure is used to characterize the biomechanical properties of the cornea.

[0032] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for analyzing the biomechanical properties of the cornea.

[0033] A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed, implements the method for analyzing the biomechanical properties of the cornea.

[0034] In this embodiment of the invention, video data of corneal deformation under force is collected by a driving device, and after analysis, a three-dimensional structure reflecting the biomechanical characteristics of the cornea at any time and at all points during the entire deformation process is directly obtained. Thus, a more comprehensive and complete corneal biomechanical characteristics are obtained, and the errors caused by data conversion in the parameter calculation process in the prior art are effectively avoided.

[0035] Existing biomechanical devices calculate the biomechanical properties of the cornea at specific time points. Specifically, they are limited to four specific time points: the initial time, the first flattening time, the maximum indentation time, and the second flattening time. These devices calculate parameters that reflect the biomechanical properties of the cornea. Moreover, the biomechanical properties calculated so far only describe the cornea at specific times and locations. Furthermore, these parameters are correlated with each other, so they cannot fully reflect the true biomechanical properties of the cornea.

[0036] The present invention creatively employs a three-dimensional structural diagram to express the biomechanical properties of the cornea. This three-dimensional structure reflects the deformation amplitude of all points on the cornea during the entire stress deformation process of the cornea, thus obtaining a more comprehensive and complete set of corneal biomechanical properties, and effectively avoiding the errors caused by data conversion in the parameter calculation process in the prior art. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0038] Figure 1 A schematic flowchart illustrating the method for analyzing corneal biomechanical properties provided in an embodiment of the present invention;

[0039] Figure 2 A detailed structural diagram of the corneal biomechanical property analysis system provided in an embodiment of the present invention;

[0040] Figure 3 A geometric diagram of corneal biomechanics provided in an embodiment of the present invention;

[0041] Figure 4 A front view of the corneal biomechanical property analysis system provided in an embodiment of the present invention;

[0042] Figure 5 A side view of the corneal biomechanical property analysis system provided in an embodiment of the present invention;

[0043] Figure 6 This is a top view of the corneal biomechanical property analysis system provided in an embodiment of the present invention.

[0044] Symbol explanation:

[0045] Drive unit-1, data acquisition module-2, corneal contour extraction module-3, change calculation module-4, 3D model construction module-5. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The purpose of this invention is to provide a method, system, and device for analyzing corneal biomechanical properties, in order to solve the problem of errors caused by data conversion in existing parameter calculation processes.

[0048] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Figure 1 An exemplary procedure for analyzing the biomechanical properties of the cornea described above is shown. The steps are described in detail below.

[0050] Step S1: While applying pressure to the cornea using a driving device, acquire video data of the cornea deforming under external force;

[0051] In one example, the pressure applied to the cornea by the actuating device ranges from 0 to 20 kPa. The actuating device applies pressure to the cornea in two ways: contact and non-contact; with contact pressure being lower than non-contact pressure. The pressure applied to the cornea by the actuating device can be adjusted according to the diameter of the eyeball. When the eyeball diameter is greater than or equal to a preset diameter, the pressure can be increased; when the eyeball diameter is smaller than the preset diameter, the pressure can be decreased.

[0052] Step S2: Extract the corneal contour from any frame of the video data using an unsupervised algorithm; the pixels on the corneal contour serve as reference points for biomechanical property analysis.

[0053] Step S3: Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image; specifically including:

[0054] Step S31: Obtain the time t1 of the first frame image and the offset Y1 of the reference point of the first frame image relative to the initial position of the cornea;

[0055] Step S32: Obtain the time t of the (n+1)th frame image. n+1 The offset Y of the reference point of the (n+1)th frame image relative to the initial position of the cornea n+1 ;

[0056] Step S33: Based on the time t1 and time t n+1 Offset Y1 and offset Y n+1 The change was obtained.

[0057] The changes include: changes in velocity and changes in displacement.

[0058] Step S34: The formula for calculating the change in velocity is:

[0059]

[0060] Step S35: The formula for calculating the displacement change is:

[0061] x n+1 =Y n+1 -Y1.

[0062] In one example, the drive unit 1 sprays air onto the cornea, causing the cornea to deform under external force. The video data of the entire corneal deformation under force is recorded by the data acquisition module 2 (Scheimplug camera). The analysis system calculates the biomechanical properties of the cornea according to the measurement time intervals.

[0063] The specific calculation process is as follows:

[0064] For each frame of the video data, unsupervised algorithms are used to extract pixels on the corneal contour as reference points for calculating biomechanical properties. With time as the Z-axis, the offset Y of the corneal contour reference point X relative to the initial position of the cornea in each frame of the video is calculated. In other words, the changes in the absolute spatial displacement of all reference points on the cornea are tracked within the video time series. By capturing the geometric structure of the corneal deformation amplitude, the biomechanical properties of the corresponding cornea are accurately determined.

[0065] Step S4: Extend the time series to a third dimension based on the two-dimensional pixel coordinates of the image, and establish a three-dimensional coordinate system;

[0066] The Z-axis of the three-dimensional coordinate system represents the time series of all images, the X-axis represents the location of the reference point in any frame of the image, and the Y-axis represents the offset of the reference point in any frame of the image relative to the initial position of the cornea.

[0067] Step S5: Obtain the geometric structure of the corneal deformation amplitude based on the change amount and the three-dimensional coordinate system; the geometric structure is used to characterize the biomechanical properties of the cornea.

[0068] The geometric structure is a three-dimensional model.

[0069] In one example, the total duration of the video data is 32ms, containing 140 frames of images, with a time interval of 0.228 = 32 / 140, and the size of each frame is 576*200.

[0070] The biomechanical properties of the cornea are determined by a factor such as Figure 3 or Figure 4 The above three-dimensional structure is used to express this, where X ranges from 0 to 576; Y ranges from 0 to 200; Z ranges from 0 to 32, and the time interval is 0.228.

[0071] The above three-dimensional structural diagram illustrates the deformation amplitude of all reference points on the corneal surface at any given time, providing a more comprehensive and complete view of the corneal biomechanical properties. Exemplary corneal biomechanical properties include elasticity, deformation, displacement, and so on.

[0072] In summary, in this embodiment of the invention, video data of corneal deformation under stress is collected by a driving device, and after analysis, a three-dimensional structure reflecting the biomechanical characteristics of all points on the cornea during the entire deformation process is directly obtained. Thus, a more comprehensive and complete set of corneal biomechanical characteristics is obtained, and the errors caused by data conversion in the parameter calculation process in the prior art are effectively avoided.

[0073] Existing biomechanical devices calculate the biomechanical properties of the cornea at specific time points. Specifically, they are limited to four specific time points: the initial time, the first flattening time, the maximum indentation time, and the second flattening time. These devices calculate parameters that reflect the biomechanical properties of the cornea. Moreover, the biomechanical properties calculated so far only describe the cornea at specific times and locations. Furthermore, these parameters are correlated with each other, so they cannot fully reflect the true biomechanical properties of the cornea.

[0074] The present invention creatively employs a three-dimensional structural diagram to express the biomechanical properties of the cornea. This three-dimensional structure reflects the deformation amplitude of all points on the cornea during the entire stress deformation process of the cornea, thus obtaining a more comprehensive and complete set of corneal biomechanical properties, and effectively avoiding the errors caused by data conversion in the parameter calculation process in the prior art.

[0075] A system for analyzing corneal biomechanical properties; please refer to [link / reference]. Figure 2 , Figure 4 , Figure 5 and Figure 6 ,include:

[0076] The drive unit 1 is used to apply pressure to the cornea; the drive unit 1 includes: an air nozzle, a jaw support, an illumination, a display screen, an adjustment knob, an operating handle, and a bracket.

[0077] Data acquisition module 2 is used to acquire video data of corneal deformation caused by external force when pressure is applied to the cornea;

[0078] The corneal contour extraction module 3 is connected to the data acquisition module 2. The corneal contour extraction module 3 is used to extract the corneal contour from any frame of the video data using an unsupervised algorithm. The pixels on the corneal contour serve as reference points for biomechanical characteristic analysis.

[0079] The change calculation module 4 is connected to the corneal contour extraction module 4, and the change calculation module 4 is used for:

[0080] Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image.

[0081] A three-dimensional coordinate system is established by extending the time series to a third dimension based on the two-dimensional pixel coordinates of the image;

[0082] The three-dimensional model construction module 5 is connected to the change calculation module 4. The three-dimensional model construction module 5 is used to obtain the geometric structure of the corneal deformation amplitude based on the change and the three-dimensional coordinate system. The geometric structure is used to characterize the biomechanical properties of the cornea.

[0083] Furthermore, the present invention also provides an electronic device, which may include: a processor, a communication interface, a memory, and a communication bus. The processor, communication interface, and memory communicate with each other via the communication bus. The processor can call a computer program stored in the memory to execute the method for analyzing corneal biomechanical properties as described above.

[0084] Furthermore, when the computer program in the aforementioned memory 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 the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This 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 described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0085] Furthermore, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the method for analyzing the biomechanical properties of the cornea.

[0086] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0087] This document uses specific examples to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the embodiments of the present invention. In summary, the content of this specification should not be construed as a limitation on the embodiments of the present invention.

Claims

1. A method for analyzing the biomechanical properties of the cornea, characterized in that, include: While applying pressure to the cornea using a driving device, video data of the cornea deforming under external force is acquired; An unsupervised algorithm is used to extract the corneal contour from any frame of the video data; the pixels on the corneal contour are used as reference points for biomechanical property analysis. Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image. Based on the two-dimensional pixel coordinates of the image, the time series is extended to a third-dimensional coordinate system to establish a three-dimensional coordinate system; The geometric structure of the corneal deformation amplitude is obtained based on the change amount and the three-dimensional coordinate system; the geometric structure is used to characterize the biomechanical properties of the cornea.

2. The method for analyzing the biomechanical properties of the cornea according to claim 1, characterized in that, Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image, specifically including: The time t1 for acquiring the first frame image, and the offset Y1 of the reference point of the first frame image relative to the initial position of the cornea; The time t for acquiring the (n+1)th frame image n+1 The offset Y of the reference point of the (n+1)th frame image relative to the initial position of the cornea n+1 ; Based on the time t1 and time t n+1 Offset Y1 and offset Y n+1 The change was obtained.

3. The method for analyzing the biomechanical properties of the cornea according to claim 2, characterized in that, The changes include: changes in velocity and changes in displacement.

4. The method for analyzing the biomechanical properties of the cornea according to claim 3, characterized in that, The formula for calculating the change in velocity is: 。 5. The method for analyzing the biomechanical properties of the cornea according to claim 3, characterized in that, The formula for calculating the displacement change is: x n+1 =Y n+1 -Y1.

6. The method for analyzing the biomechanical properties of the cornea according to claim 1, characterized in that, The Z-axis of the three-dimensional coordinate system represents the time series of all images, the X-axis represents the location of the reference point in any frame of the image, and the Y-axis represents the offset of the reference point in any frame of the image relative to the initial position of the cornea.

7. The method for analyzing the biomechanical properties of the cornea according to claim 1, characterized in that, The geometric structure is a three-dimensional model.

8. A system for analyzing the biomechanical properties of the cornea, characterized in that, include: A drive mechanism used to apply pressure to the cornea; The data acquisition module is used to acquire video data of corneal deformation caused by external force when pressure is applied to the cornea; A corneal contour extraction module, connected to the data acquisition module, is used to extract the corneal contour from any frame of the video data using an unsupervised algorithm; the pixels on the corneal contour serve as reference points for biomechanical characteristic analysis. The change calculation module, connected to the corneal contour extraction module, is used for: Based on the time series of any frame image, calculate the offset of the reference point of any frame image relative to the initial position of the cornea, and obtain the change in the absolute spatial displacement of all reference points on any frame image. Based on the two-dimensional pixel coordinates of the image, the time series is extended to a third-dimensional coordinate system to establish a three-dimensional coordinate system; A three-dimensional model construction module, connected to the change calculation module, is used to obtain the geometric structure of the corneal deformation amplitude based on the change and the three-dimensional coordinate system; the geometric structure is used to characterize the biomechanical properties of the cornea.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for analyzing the corneal biomechanical properties as described in any one of claims 1-7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed, it implements the method for analyzing corneal biomechanical properties as described in any one of claims 1-7.

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