A system for measuring parameters of a contact lens based on SD-OCT

Abstract

This invention provides a corneal contact lens parameter measurement system based on SD-OCT. The system includes a light source module, a reference arm module, a sample arm module, a spectral detection module, and a control and processing module. Specifically, the light source module, reference arm module, and sample arm module construct a Michelson interference structure and obtain interference light. Then, after the spectral detection module detects the intensity signal of the interference light and converts it into a digital electrical signal, the control and processing module processes the digital electrical signal to obtain an optical coherence tomography (OCT) image. Based on the OCT image, various geometric parameters of the corneal contact lens are automatically and efficiently identified and calculated. The system is simple, convenient, and fast to operate, eliminating the need for manual subjective readings and significantly improving measurement accuracy.

Description

Technical Field

[0001] This invention generally relates to the field of lens testing technology, and specifically to a corneal contact lens parameter measurement system based on spectral domain optical coherence tomography. Background Technology

[0002] Contact lenses (also known as corneal contact lenses) can be broadly classified into rigid gas permeable (RGP) and soft gas permeable (WP) lenses based on their manufacturing materials. They are widely used due to their advantages such as small size, light weight, and wide field of vision. Compared to eyeglasses, contact lenses come into direct contact with the cornea, making material safety and parameter reliability paramount. Furthermore, accurately measuring the key geometric parameters of contact lenses not only ensures the accuracy of clinical refractive correction but also provides crucial reference data for contact lens production and manufacturing.

[0003] Currently, the relevant technology uses a corneal contact lens measuring projector to measure various geometric parameters. However, this method has a limited range of measurable parameters and requires trained professionals to operate, which is time-consuming, labor-intensive, and has a low degree of automation, seriously affecting production efficiency. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the related technologies, it is desirable to provide a corneal contact lens parameter measurement system based on SD-OCT, which can automatically and efficiently measure a variety of geometric parameters of corneal contact lenses, is convenient, fast, easy to operate, and has high measurement accuracy.

[0005] This invention provides a corneal contact lens parameter measurement system based on spectral domain optical coherence tomography. The measurement system includes a light source module, a reference arm module, a sample arm module, a spectral detection module, and a control and processing module.

[0006] The first end of the light source module is connected to the port of the reference arm module, the second end of the light source module is connected to the first end of the sample arm module, the third end of the light source module is connected to the first end of the spectral detection module, the second end of the spectral detection module is connected to the first end of the control and processing module, and the second end of the control and processing module is connected to the second end of the sample arm module.

[0007] The light source module is configured to emit light and transmit the emitted light after beam splitting to the reference arm module and the sample arm module respectively, and receives the reflected light returned by the reference arm module and the sample arm module respectively, the reflected light being used to generate interference light;

[0008] The reference arm module is configured to generate reference reflected light, and the sample arm module is configured to scan the corneal contact lens and obtain sample reflected light;

[0009] The spectral detection module is configured to detect the light intensity signal of the interference light and convert the light intensity signal into a digital electrical signal;

[0010] The control and processing module is configured to acquire the digital electrical signal and control the sample arm module and the spectral detection module to work synchronously; process the digital electrical signal to obtain an optical coherence tomography (OCT) image; and, based on the OCT image, identify and calculate the geometric parameters of the corneal contact lens.

[0011] Optionally, in some embodiments of the present invention, the control processing module is further configured to preprocess the optical coherence tomography image before identifying and calculating the geometric parameters of the corneal contact lens based on the optical coherence tomography image.

[0012] Optionally, in some embodiments of the present invention, the preprocessing includes at least one of dispersion compensation, signal-to-noise ratio enhancement, image correction, and contour extraction.

[0013] Optionally, in some embodiments of the present invention, the light source module includes a coherent light source, an optical fiber circulator, and an optical fiber coupler;

[0014] The output end of the coherent light source is connected to the first end of the fiber optic circulator, the second end of the fiber optic circulator is connected to the first end of the fiber optic coupler, the third end of the fiber optic circulator is connected to the first end of the spectral detection module, the second end of the fiber optic coupler is connected to the port of the reference arm module, and the third end of the fiber optic coupler is connected to the first end of the sample arm module.

[0015] Optionally, in some embodiments of the present invention, the light source module further includes an indicator light source and a wavelength division multiplexer;

[0016] The output terminals of the indicator light source and the coherent light source are both connected to the input terminal of the wavelength division multiplexer, and the output terminal of the wavelength division multiplexer is connected to the first end of the fiber optic circulator.

[0017] Optionally, in some embodiments of the present invention, a polarization controller is provided between the second end of the fiber coupler and the port of the reference arm module, and between the third end of the fiber coupler and the first end of the sample arm module.

[0018] Optionally, in some embodiments of the present invention, the reference arm module includes an optical fiber collimator, a dispersion compensation mirror, an adjustable aperture, a focusing lens, and a coated reflector arranged sequentially along the transmission optical path.

[0019] Optionally, in some embodiments of the present invention, the focusing lens and the coated mirror are fixed on a single-axis moving platform to match the optical path of the sample arm module.

[0020] Optionally, in some embodiments of the present invention, the sample arm module includes an adjustable attenuator, an optical fiber collimator, an X-Y dual-axis scanning galvanometer, and an imaging objective, arranged sequentially along the transmission optical path.

[0021] Optionally, in some embodiments of the present invention, the sample arm module further includes a sample stage, which is a liquid pool provided with a corneal contact lens support structure.

[0022] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

[0023] This invention provides a corneal contact lens parameter measurement system based on SD-OCT. This system constructs a Michelson interference structure using a light source module, a reference arm module, and a sample arm module to obtain interference light. Then, after the spectral detection module detects the intensity signal of the interference light and converts it into a digital electrical signal, the control processing module processes the digital electrical signal to obtain an optical coherence tomography (OCT) image. Based on the OCT image, it automatically and efficiently identifies and calculates various geometric parameters of the corneal contact lens. The system is simple, convenient, and fast to operate, and eliminates the need for manual subjective readings, significantly improving measurement accuracy. Attached Figure Description

[0024] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0025] Figure 1 A structural block diagram of a corneal contact lens parameter measurement system based on SD-OCT provided in an embodiment of the present invention;

[0026] Figure 2 A simplified schematic diagram of a corneal contact lens parameter measurement system based on SD-OCT provided in an embodiment of the present invention;

[0027] Figure 3 This invention provides a specific example of a corneal contact lens parameter measurement system based on SD-OCT.

[0028] Figure 4 A complete three-dimensional imaging schematic diagram of a corneal contact lens provided in an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of a B-scan cross-section with automatically marked key geometric parameters provided in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of an operation main interface provided in an embodiment of the present invention;

[0031] Figure 7 A schematic diagram illustrating the distribution and data processing of the outer surface curvature radius provided in an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram illustrating the distribution and data processing of normal thickness as provided in an embodiment of the present invention.

[0033] Figure label:

[0034] 100 - SD-OCT-based corneal contact lens parameter measurement system; 101 - Light source module; 1011 - Coherent light source; 1012 - Fiber circulator; 1013 - Fiber coupler; 1014 - Indicator light source; 1015 - Wavelength division multiplexer; 1016 - Polarization controller; 102 - Reference arm module; 1021 - Fiber collimator for reference arm module; 1022 - Dispersion compensation mirror; 1023 - Adjustable aperture; 1024 - Focusing. Lens, 1025-coated reflector; 103-sample arm module, 1031-adjustable attenuator, 1032-fiber collimator for sample arm module, 1033-X-Y dual-axis scanning galvanometer, 1034-imaging objective lens, 1035-sample stage; 104-spectral detection module; 105-control and processing module, 1051-data acquisition unit, 1052-data processing unit, 1053-automatic calculation unit, 1054-graphics processing unit. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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.

[0036] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the described embodiments of the invention can be implemented in orders other than those illustrated or described herein.

[0037] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product, or device.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] To facilitate a better understanding of the present invention, it is now explained through... Figures 1 to 8 This invention provides a detailed description of the corneal contact lens parameter measurement system based on SD-OCT (Spectral domain-optical coherence tomography). Please refer to [link to relevant documentation]. Figure 1 This is a structural block diagram of a corneal contact lens parameter measurement system based on SD-OCT provided in an embodiment of the present invention. The measurement system 100 includes a light source module 101, a reference arm module 102, a sample arm module 103, a spectral detection module 104, and a control and processing module 105. The first end of the light source module 101 is connected to the port of the reference arm module 102, the second end of the light source module 101 is connected to the first end of the sample arm module 103, the third end of the light source module 101 is connected to the first end of the spectral detection module 104, the second end of the spectral detection module 104 is connected to the first end of the control and processing module 105, and the second end of the control and processing module 105 is connected to the second end of the sample arm module 103.

[0040] It should be noted that in this embodiment of the invention, the light source module 101 can emit light and transmit the split emitted light to the reference arm module 102 and the sample arm module 103 respectively, and receive the reflected light returned from the reference arm module 102 and the sample arm module 103 respectively. This reflected light is used to generate interference light. The reference arm module 102 can generate reference reflected light, and the sample arm module 103 can scan the corneal contact lens and obtain the sample reflected light. The spectral detection module 104 can detect the light intensity signal of the interference light and convert the light intensity signal into a digital electrical signal. The control processing module 105 can acquire the digital electrical signal and control the sample arm module 103 and the spectral detection module 104 to work synchronously; process the digital electrical signal to obtain an optical coherence tomography (OCT) image; and, based on the OCT image, identify and calculate the geometric parameters of the corneal contact lens.

[0041] Further, please refer to Figure 2This is a simplified schematic diagram of a corneal contact lens parameter measurement system based on SD-OCT provided by an embodiment of the present invention. For example, firstly, the low-coherence light emitted from the light source module 101 passes through a beam splitter, is reflected by the plane mirror in the reference arm module 102 and the sample in the sample arm module 103, and then coherently superimposed. The interference light is received by the spectral detection module 104 and forms an interference intensity spectrum I(k). Then, the interference intensity spectrum I(k) is acquired and processed by a computer to obtain the light intensity information I(z) of the sample at different depths, i.e., A-Scan. Then, combined with the X-axis scanning galvanometer, multiple A-Scans of the sample along the scanning line are obtained, at which point a tomographic image of the sample, i.e., a B-Scan image, can be obtained. Then, combined with the Y-axis scanning galvanometer, multiple B-Scans are scanned line by line, at which point a three-dimensional image of the sample can be obtained.

[0042] For example, now combined Figure 3 As shown, the components of the measurement system 100 in this embodiment of the invention will be described in detail.

[0043] For example, the light source module 101 in the measurement system 100 includes, but is not limited to, a coherent light source 1011, an optical fiber circulator 1012, and an optical fiber coupler 1013. In this embodiment of the invention, by setting the optical fiber circulator 1012, the emitted light from the light source can be transmitted unidirectionally (e.g., from port 1 to port 2), thus preventing the light source from burning out. Specifically, the output end of the coherent light source 1011 is connected to the first end of the optical fiber circulator 1012, the second end of the optical fiber circulator 1012 is connected to the first end of the optical fiber coupler 1013, the third end of the optical fiber circulator 1012 is connected to the first end of the spectral detection module 104, the second end of the optical fiber coupler 1013 is connected to the port of the reference arm module 102, and the third end of the optical fiber coupler 1013 is connected to the first end of the sample arm module 103. For example, the coherent light source 1011 has a center wavelength of 840 nm and a bandwidth of 60 nm; the fiber coupler 1013 has a splitting ratio of 10:90, that is, 10% of the light energy is transmitted to the reference arm module 102, while 90% of the light energy is transmitted to the sample arm module 103.

[0044] Optionally, the light source module 101 in the measurement system 100 further includes an indicator light source 1014 and a wavelength division multiplexer 1015. In this embodiment of the invention, the indicator light source 1014 can indicate the position of the scanning spot for the sample arm module 103, facilitating positioning and precise measurement. The output terminals of both the indicator light source 1014 and the coherent light source 1011 are connected to the input terminal of the wavelength division multiplexer 1015, while the output terminal of the wavelength division multiplexer 1015 is connected to the first end of the fiber optic circulator 1012. For example, the center wavelength of the indicator light source 1014 is 633 nm.

[0045] Optionally, a polarization controller 1016 may be provided between the second end of the fiber coupler 1013 and the port of the reference arm module 102, and between the third end of the fiber coupler 1013 and the first end of the sample arm module 103, thereby enabling adjustment and optimization of the polarization state of the transmitted light.

[0046] For example, the reference arm module 102 in the measurement system 100 includes, but is not limited to, an optical fiber collimator 1021, a dispersion compensation mirror 1022, an adjustable aperture 1023, a focusing lens 1024, and a coated reflector 1025 arranged sequentially along the transmission optical path. For example, the light with 10% energy output from the fiber coupler 1013 first passes through the polarization controller 1016 and then enters the fiber collimator 1021. The fiber collimator 1021 can form a parallel spatial beam of light transmitted in the fiber. The parallel spatial beam then enters the dispersion compensation mirror 1022. The advantage of this arrangement is that it can perform dispersion compensation on the imaging objective lens in the sample arm module 103. Next, the light emitted from the dispersion compensation mirror 1022 passes through the adjustable aperture 1023. At this time, the reference light intensity can be adjusted and stray light can be filtered to improve the signal-to-noise ratio of the final interference signal. Then, the light passing through the adjustable aperture 1023 is focused onto the coated mirror 1025 by the focusing lens 1024 and finally returns to the fiber coupler 1013 along the same path. The focusing lens 1024 and the coated mirror 1025 can be fixed on a single-axis moving platform and the optical path of the sample arm module 103 can be matched by horizontal lateral movement.

[0047] For example, the sample arm module 103 in the measurement system 100 includes, but is not limited to, an adjustable attenuator 1031, an optical fiber collimator 1032, an X-Y dual-axis scanning galvanometer 1033, and an imaging objective lens 1034 arranged sequentially along the transmission optical path. For example, the light output from the fiber coupler 1013 with 90% energy first passes through the polarization controller 1016 and then enters the adjustable attenuator 1031. This adjustable attenuator 1031 can adjust the intensity of the sample reflected signal light to adjust the signal-to-noise ratio of the final interference signal. Next, the light emitted from the adjustable attenuator 1031 passes through the fiber collimator 1032 to form a parallel spatial beam before entering the X-Y dual-axis scanning galvanometer 1033, used for point-by-point scanning of the sample in the X and Y directions. Then, the light emitted from the X-Y dual-axis scanning galvanometer 1033 is focused onto the sample surface by the imaging objective 1034 to reduce the scanning spot size, improve the system's lateral resolution, and increase the intensity of the sample reflected light. Finally, the sample reflected light returns to the fiber coupler 1013 along the same path. The fiber collimator 1032, the X-Y dual-axis scanning galvanometer 1033, and the imaging objective 1034 can be fixed as a whole on an axially adjustable moving platform, thereby adjusting the objective lens focal length for clearer imaging. In addition, the sample stage 1035 of the sample arm module 103 can be a liquid pool with a corneal contact lens support structure. The advantage of this configuration is that it can ensure that the corneal contact lens will not dehydrate or deform during the measurement process, thereby improving the measurement accuracy.

[0048] For example, the spectral detection module 104 in the measurement system 100 can be a high-speed, high-resolution OCT (Optical Coherence Tomography) spectrometer. This spectrometer has a maximum linear rate of 130 kHz, and when used with a high-speed galvanometer, it can achieve real-time display of two-dimensional B-scan images. If the galvanometer is set to scan 500 points per cycle, meaning each B-scan image contains 500 A-scans, the system can display up to 50 frames per second in real time, suitable for rapid testing of production line products. For instance, the reflected light from the reference arm module 102 and the sample arm module 103 first undergoes polarization optimization by the polarization controller 1016, and then enters the fiber coupler 1013 where interference occurs. Next, the interference light is unidirectionally transmitted from port 2 to port 3 of the fiber optic circulator 1012, and after polarization optimization by the polarization controller 1016, it enters the spectrometer. The spectrometer then records the interference intensity spectrum of the interference light and converts the interference light intensity at different wavelengths into digital electrical signals using a CCD array.

[0049] Alternatively, the control processing module 105 in the measurement system 100 may include a data acquisition unit 1051, a data processing unit 1052, and an automatic calculation unit 1053. The data acquisition unit 1051 can acquire digital electrical signals and control the sample arm module 103 and the spectral detection module 104 to work synchronously, ensuring that each scanning position of the galvanometer is completely recorded by the spectrometer, and then moving to the next scanning position after acquisition is completed. For example, the data acquisition unit 1051 transmits the digital electrical signals generated by the spectrometer to the computer workstation for recording via a USB 3.0 data cable, and connects the control terminals of the galvanometer and the spectrometer to the PCI board port of the computer workstation for synchronous control via a synchronous control line, using the device's external trigger mode to achieve synchronous control.

[0050] The data processing unit 1052 can process digital electrical signals to obtain optical coherence tomography (OCT) images. For example, the data processing unit 1052 can perform Fourier transform on the original spectral intensity signal I(k) through LabVIEW software programming to obtain light intensity signals I(z) at different depths of the sample, retain positive information and remove mirror data, and then combine it with a galvanometer to scan different positions point by point to finally form a two-dimensional or three-dimensional original OCT image.

[0051] Furthermore, the automatic calculation unit 1053 can identify and calculate the geometric parameters of the corneal contact lens based on optical coherence tomography images. For example, according to the settings of the parameters to be measured, the automatic calculation unit 1053 uses a pixel grayscale value point-by-point comparison method to identify feature points (such as the lowest point, left and right extreme position points, etc.) in the extracted corneal contact lens contour, and determines the measurement starting position of the relevant geometric parameters. Then, according to the geometric parameters to be measured by the user, it completes the automatic calculation of the key geometric parameters of the corneal contact lens, thereby realizing the efficient measurement of global multiple parameters such as thickness at any point, outer diameter, and inner and outer surface curvature radius, which is convenient and fast.

[0052] Optionally, the control processing module 105 in the measurement system 100 can also preprocess the optical coherence tomography (OCT) image before identifying and calculating the geometric parameters of the corneal contact lens based on the OCT image. This preprocessing includes, but is not limited to, at least one of dispersion compensation, signal-to-noise ratio enhancement, image correction, and contour extraction. For example, the data processing unit 1052 can calculate the dispersion compensation coefficient for each wavelength based on the light source band to compensate for the dispersion caused by sample imaging. It can also use software programming to compensate for the dispersion at each wavelength in real time, making the displayed image clearer and sharper. Simultaneously, it can use an adaptive threshold algorithm to improve the signal-to-noise ratio of the image and increase the contrast of the displayed image.

[0053] The graphics processing unit 1054 included in the control processing module 105 can perform image correction and contour extraction on the optimized high-resolution image. The reason for this setting is that the galvanometer scans back and forth in an equal angle manner. Except for the center position of the image, the equipathic points at other positions are spread out in a fan shape. If the uncorrected image is used directly to calculate the geometric dimensions, it will introduce a large error. Therefore, it is necessary to establish a mathematical model based on the system parameters in advance, and perform corresponding image correction on the system after analysis. The position difference of different scanning points is compensated to restore the image to the actual shape of the corneal contact lens. At the same time, the contour of the corrected corneal contact lens cross-section is extracted by algorithms such as Gaussian filtering, adaptive thresholding and contour extraction.

[0054] Practical use Figure 3 When measuring the geometric parameters of a corneal contact lens using the measurement system 100 shown, this embodiment of the invention first activates the measurement system 100 and calibrates it using a standard lens. Next, the corneal contact lens to be tested is placed in the liquid pool with a support structure in the sample arm module 103. A saline solution is injected to ensure the lens is fully immersed in the solution, and the edge of the lens is adjusted to be approximately flush with the liquid surface. Simultaneously, the red indicator light spot of the indicator light source 1014 in the light source module 101 is observed to be approximately located near the center of the corneal contact lens.

[0055] Next, a rapid full-range (16mm*16mm) scan is performed on the contact lens under test. Specifically, the X-Y dual-axis scanning galvanometer 1033 in the sample arm module 103 performs a line-by-line scan in the Y direction (total length 16mm, each line 16mm long). The control processing module 105 obtains a complete three-dimensional image of the contact lens under test through imaging, such as... Figure 4 As shown. Subsequently, the control processing module 105 compares the outer diameters of adjacent B-scan cross-sectional images and records the B-scan cross-sectional image with the largest outer diameter to determine the B-scan image at the center position of the contact lens under test, as shown. Figure 5 As shown.

[0056] Furthermore, such as Figure 6 As shown, the measurement accuracy and parameters are selected in the software interface, and a B-scan image of the center position of the contact lens to be tested is formed. Figure 5As shown, the control processing module 105 identifies the left and right extreme edge points of the contact lens under test to calculate the outer diameter of the contact lens; identifies the center point of the image to calculate the center thickness of the contact lens; performs data fitting on the inner and outer curves of the image to calculate the inner and outer surface curvature radii of the contact lens; and calculates the inner sag by connecting the inner vertex to the outer diameter and the outer sag by connecting the outer vertex to the outer diameter. Finally, the selected basic parameters are automatically calculated and displayed on the software interface. It should also be noted that measurements of other positions or geometric parameters can be performed manually, which has a wide range of applications. For example, by taking points at equal intervals on the outer surface, the outer surface curvature radius of any corresponding region can be calculated, and a fitting curve of the outer surface curvature radius distribution of the contact lens under test can be provided. Figure 7 As shown; by connecting the vector directions of any points on the inner and outer surfaces, the thickness at any location is calculated, and the normal thickness distribution curve of the contact lens under test is given, as shown. Figure 8 As shown. Meanwhile, the measurement system 100 has been tested and calibrated according to the testing methods specified in JJF 1148-2006 "Calibration Specification for Corneal Contact Lens Testing Instruments". All indicators meet the error requirements and have high reliability, namely: ① Diameter measurement range meets (8-16) mm, with a diameter indication error of ±50 μm; ② Center thickness measurement range meets (0-1.0) mm, with a center thickness indication error of ±5 μm; ③ Curvature radius measurement range meets (6.5-9.5) mm, with a curvature radius indication error of ±20 μm and a curvature radius measurement repeatability of 10 μm.

[0057] The SD-OCT-based corneal contact lens parameter measurement system provided in this invention constructs a Michelson interference structure using a light source module, a reference arm module, and a sample arm module to obtain interference light. Then, after the spectral detection module detects the intensity signal of the interference light and converts it into a digital electrical signal, the control processing module processes the digital electrical signal to obtain an optical coherence tomography (OCT) image. Based on the OCT image, the system automatically and efficiently identifies and calculates various geometric parameters of the corneal contact lens. The system is simple, convenient, and fast to operate, and eliminates the need for manual subjective readings, significantly improving measurement accuracy.

[0058] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A corneal contact lens parameter measurement system based on SD-OCT, characterized in that, The measurement system includes a light source module, a reference arm module, a sample arm module, a spectral detection module, and a control and processing module. The first end of the light source module is connected to the port of the reference arm module, the second end of the light source module is connected to the first end of the sample arm module, the third end of the light source module is connected to the first end of the spectral detection module, the second end of the spectral detection module is connected to the first end of the control and processing module, and the second end of the control and processing module is connected to the second end of the sample arm module. The light source module is configured to emit light and transmit the emitted light after beam splitting to the reference arm module and the sample arm module respectively, and receives the reflected light returned by the reference arm module and the sample arm module respectively, the reflected light being used to generate interference light; The reference arm module is configured to generate reference reflected light, and the sample arm module is configured to scan the corneal contact lens and obtain sample reflected light; The sample arm module includes an adjustable attenuator, an optical fiber collimator, an X-Y dual-axis scanning galvanometer, an imaging objective lens, and a sample stage arranged sequentially along the transmission optical path. The sample stage is a liquid pool with a corneal contact lens support structure. When measuring parameters, a salt solution is injected into the liquid pool so that the corneal contact lens to be tested is completely immersed in the solution, and the edge of the corneal contact lens to be tested is adjusted to be basically flush with the liquid surface. The reference arm module includes an optical fiber collimator, a dispersion compensation mirror, an adjustable aperture, a focusing lens, and a coated reflector arranged sequentially along the transmission optical path. The spectral detection module is configured to detect the light intensity signal of the interference light and convert the light intensity signal into a digital electrical signal; The control processing module is configured to acquire the digital electrical signal and control the sample arm module and the spectral detection module to work synchronously. The digital electrical signal is processed to obtain an optical coherence tomography (OCT) image; and the geometric parameters of the corneal contact lens are identified and calculated based on the OCT image. The control processing module is further configured to: utilize an automatic calculation unit to identify feature points in the extracted corneal contact lens contour based on the settings of the parameters to be measured, using a pixel grayscale value point-by-point comparison method, and determine the measurement starting position of relevant geometric parameters; then, based on the geometric parameters to be measured selected by the user, automatically calculate the key geometric parameters of the corneal contact lens; by comparing the outer diameters of adjacent B-scan cross-sectional images, record the B-scan cross-sectional image with the largest outer diameter to determine the B-scan image of the center position of the corneal contact lens to be measured, and image the B-scan image of the center position of the corneal contact lens to be measured; identify the left and right extreme edge points of the corneal contact lens to be measured to calculate the outer diameter of the corneal contact lens to be measured; and identify the center position point of the image to calculate the center thickness of the corneal contact lens to be measured. The inner and outer curves of the image are fitted to calculate the radius of curvature of the inner and outer surfaces of the corneal contact lens under test; the inner sagitta is calculated by connecting the inner vertex and the outer diameter. The external sagittal height is calculated by connecting the outer vertex to the outer diameter.

2. The corneal contact lens parameter measurement system based on SD-OCT according to claim 1, characterized in that, The control processing module is further configured to preprocess the optical coherence tomography (OCT) image before identifying and calculating the geometric parameters of the corneal contact lens based on the OCT image.

3. The corneal contact lens parameter measurement system based on SD-OCT according to claim 2, characterized in that, The preprocessing includes at least one of dispersion compensation, signal-to-noise ratio enhancement, image correction, and contour extraction.

4. A corneal contact lens parameter measurement system based on SD-OCT according to any one of claims 1 to 3, characterized in that, The light source module includes a coherent optical source, an optical fiber circulator, and an optical fiber coupler; The output end of the coherent light source is connected to the first end of the fiber optic circulator, the second end of the fiber optic circulator is connected to the first end of the fiber optic coupler, the third end of the fiber optic circulator is connected to the first end of the spectral detection module, the second end of the fiber optic coupler is connected to the port of the reference arm module, and the third end of the fiber optic coupler is connected to the first end of the sample arm module.

5. The corneal contact lens parameter measurement system based on SD-OCT according to claim 4, characterized in that, The light source module also includes an indicator light source and a wavelength division multiplexer; The output terminals of the indicator light source and the coherent light source are both connected to the input terminal of the wavelength division multiplexer, and the output terminal of the wavelength division multiplexer is connected to the first end of the fiber optic circulator.

6. The corneal contact lens parameter measurement system based on SD-OCT according to claim 5, characterized in that, A polarization controller is provided between the second end of the fiber optic coupler and the port of the reference arm module, and between the third end of the fiber optic coupler and the first end of the sample arm module.

7. The corneal contact lens parameter measurement system based on SD-OCT according to claim 6, characterized in that, The focusing lens and the coated mirror are fixed on a single-axis moving platform to match the optical path of the sample arm module.

Images