An iris lesion geometry parameter measurement system based on laser triangulation

Abstract

The application discloses an iris lesion geometric parameter measurement system based on laser triangulation, and particularly relates to the technical field of optical measurement and geometric calculation, and comprises a laser projection module, which is used for forming an iris surface topography modulation optical pattern; an image acquisition module, which is used for acquiring the laser pattern after the iris surface modulation; a data processing module, which processes the laser pattern image and extracts sub-pixel coordinates of a lesion area of the laser pattern; a three-dimensional coordinate construction module, which converts the sub-pixel coordinates of the lesion area into three-dimensional space coordinates; and a geometric parameter measurement module, which calculates geometric parameters of the lesion area. The laser projection module, the image acquisition module, the data processing module, the three-dimensional coordinate construction module and the geometric parameter measurement module are combined to construct the iris lesion geometric parameter measurement system based on laser triangulation, so that the limitations of the prior art in the aspects of measurement dimension, precision, efficiency and automation are solved.

Description

Technical Field

[0001] This invention relates to the fields of optical measurement and geometric calculation technology, and more specifically, to a system for measuring the geometric parameters of iris lesions based on laser triangulation. Background Technology

[0002] As a crucial component of the eyeball, the accurate measurement of lesions on the iris surface (such as cysts, nevi, nodules, and atrophic pits) is of great significance in clinical ophthalmology. Currently, the clinical assessment of iris lesions mainly relies on two-dimensional morphological observation using optical equipment such as slit-lamp microscopes. Doctors judge the size, outline, and general protrusion of the lesions by visual inspection and experience. This method is inherently subjective and makes it difficult to obtain precise three-dimensional geometric parameters of the lesions, such as vertical height, three-dimensional surface area, and local curvature. This, to some extent, affects the observation of disease progression and the objective evaluation of treatment efficacy.

[0003] Existing geometric parameter measurement systems for iris lesions can basically meet the measurement needs, but they still have some shortcomings in practical use: First, the measurement dimensions and efficiency are insufficient. Existing measurement technologies mainly use OCT and UBM cross-sectional scanning technologies, which require high fixation from the patient and are prone to stitching errors due to micro-movements of the eyeball. Second, geometric parameter extraction is difficult. Existing technologies focus on providing high-resolution cross-sectional images, and the process of calculating the lesion surface area and curvature data in three-dimensional data is relatively complex and not efficient enough. Third, the measurement accuracy is insufficient. Existing technologies do not comprehensively measure the diameter, height, spacing, three-dimensional area and curvature of iris lesions, and lack rapid and high-precision geometric measurements of the iris surface morphology.

[0004] Therefore, there is an urgent need for a measurement system to address the limitations of existing technologies in terms of measurement dimensions, accuracy, efficiency, and automation. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, the present invention provides a system for measuring the geometric parameters of iris lesions based on laser triangulation, which solves the problems mentioned in the background art through the following solutions.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a system for measuring the geometric parameters of iris lesions based on laser triangulation, comprising:

[0007] Laser projection module: A structured laser beam is generated by a laser and projected onto the surface of the iris of the eye to be tested to form an optical pattern that modulates the morphology of the iris surface;

[0008] Image acquisition module: Based on the fixed angle formed by the optical axis and the laser projection module, it acquires an image of the modulated laser pattern on the iris surface;

[0009] Data processing module: processes the image of the laser pattern, extracts the sub-pixel coordinates of the lesion area of ​​the laser pattern, and performs a pre-set triangulation relationship based on the laser projection module and the image acquisition module to map the two-dimensional image points onto the corresponding three-dimensional laser plane;

[0010] 3D coordinate construction module: converts the subpixel coordinates of the lesion area into 3D spatial coordinates, the 3D spatial coordinates including the X-axis iris lesion diameter, the Y-axis iris lesion height, and the Z-axis iris lesion spacing;

[0011] Geometric parameter measurement module: Based on the three-dimensional spatial coordinates, calculate the geometric parameters of the lesion area, including the lesion area and the curvature of the lesion area.

[0012] Preferably, the three-dimensional coordinate construction module converts the sub-pixel coordinates of the lesion region into three-dimensional spatial coordinates, wherein the three-dimensional spatial coordinates include the X-axis iris lesion diameter, the Y-axis iris lesion height, and the Z-axis iris lesion spacing.

[0013] D1: Receive 3D point coordinates ;

[0014] Receive the three-dimensional point coordinates of the lesion area in the camera coordinate system from the data processing module. These points are all precisely located on the previously calibrated laser plane, representing all three-dimensional points in the lesion area. Transform to the iris coordinate system to obtain the new coordinates. ,in Indicates the horizontal position of the point on the iris plane. Indicates the vertical position of the point on the iris plane. Indicates the height of the point relative to the iris reference plane. Indicates a raised area Indicates a depression;

[0015] D2: Calculate the diameter of the iris lesion on the X-axis, the height of the iris lesion on the Y-axis, and the distance between the iris lesions on the Z-axis in three-dimensional spatial coordinates;

[0016] The X-axis diameter of the iris lesion is calculated by projecting all lesion points onto the iris reference plane. ;

[0017] The Y-axis iris lesion height, where height usually refers to the degree of protrusion or depression of the lesion, i.e. Change ;

[0018] The Z-axis iris lesion spacing is the distance between the center points of the lesion areas. The absolute value of the coordinates represents the average depth of the entire lesion relative to the iris reference plane. This refers to the average depth of the lesion.

[0019] Preferably, the geometric parameter measurement module calculates the geometric parameters of the lesion region based on the three-dimensional spatial coordinates, wherein the geometric parameters include the lesion area and the lesion curvature.

[0020] E1: Receive new coordinates from D1 Calculate the area of ​​the lesion;

[0021] The lesion area refers to the actual surface area of ​​the lesion area in three-dimensional space; triangular mesh construction uses the Delaunay triangulation algorithm to connect discrete three-dimensional coordinate points into a continuous triangular mesh. This mesh is a geometric approximation of the lesion surface, which can be simply understood as covering the iris lesion surface with countless tiny triangles.

[0022] At this point, calculating the surface area of ​​the triangular mesh yields the area of ​​the lesion region. This is based on triangles formed by the coefficients (constants) of the equations for planes A, B, C, and D; the area of ​​each triangle is then calculated. The total surface area of ​​the lesion area is obtained by summing the faces of all the triangles.

[0023] E2: Receive new coordinates from D1 Calculate the curvature of the lesion area;

[0024] Curvature quantifies the degree of curvature of a surface at a point. Calculating the curvature of a lesion area can determine whether it is a sharp protrusion, a gentle bulge, or a depression, which is of great value in the diagnosis of ocular lesions (such as cysts, tumors, and pigmented nevi). Curvature is usually calculated in two ways: Gaussian curvature and mean curvature. Mean curvature is used to estimate the curvature of a three-dimensional coordinate point. This is done by calculating the difference between the position of the vertex of the triangle formed by the coefficients (constants) of the equations of planes A, B, C, and D and the positions of the other adjacent vertices, thus estimating the inherent curvature of the surface at that point. Taking vertex A as an example, the specific curvature calculation formula is as follows:

[0025]

[0026] in A represents the average curvature of a vertex, and A represents the area of ​​influence of that vertex. This represents the cotangent value of the angle between vertex A and the adjacent edges i and j. This calculation will output a curvature value for each vertex in the lesion area. By estimating the sum of the curvature values ​​of the iris lesion area, the curvature of the lesion area is obtained.

[0027] The technical effects and advantages of this invention are as follows:

[0028] 1. This invention utilizes the principle of laser triangulation, combined with sub-pixel coordinate extraction and three-dimensional coordinate construction, to obtain the three-dimensional morphological information of the iris lesion area in a non-contact and high-precision manner, thereby achieving high-precision measurement of the three-dimensional geometric parameters of the iris lesion and solving the shortcomings of traditional methods in the extraction of three-dimensional geometric parameters.

[0029] 2. This invention combines structured light projection with image acquisition, and based on image processing and geometric calculation processes, it can quickly complete the identification of lesion areas and parameter calculation after a single shot. This process reduces operational complexity and improves measurement efficiency and automation.

[0030] 3. In the data processing module, the present invention uses the gray-scale centroid method to extract the center of the laser stripe at the sub-pixel level, and combines the camera calibration parameters and triangulation relationship to accurately map the image coordinates to three-dimensional space to improve the accuracy of geometric parameter measurement.

[0031] 4. This invention achieves rapid, accurate, and automated measurement of the three-dimensional geometric parameters of iris lesions by organically combining laser triangulation and image processing technology, effectively overcoming the limitations of existing technologies in terms of measurement dimension, accuracy, efficiency, and automation. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall module structure of the present invention.

[0033] Figure 2 This is a schematic diagram of the laser projection module structure of the present invention.

[0034] Figure 3 This is a schematic diagram of the image acquisition module structure of the present invention.

[0035] Figure 4 This is a schematic diagram of the data processing module structure of the present invention.

[0036] Figure 5 This is a schematic diagram of the logical execution structure of the present invention. Detailed Implementation

[0037] 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.

[0038] Please see Figures 1-5As shown, this embodiment of the invention provides a system for measuring the geometric parameters of iris lesions based on laser triangulation. The system comprises a laser projection module, an image acquisition module, a data processing module, a three-dimensional coordinate construction module, and a geometric parameter measurement module. The system includes:

[0039] Laser projection module: A structured laser beam is generated by a laser and projected onto the surface of the iris of the eye to be tested to form an optical pattern that modulates the morphology of the iris surface;

[0040] Image acquisition module: Based on the fixed angle formed by the optical axis and the laser projection module, it acquires an image of the modulated laser pattern on the iris surface;

[0041] Data processing module: processes the image of the laser pattern, extracts the sub-pixel coordinates of the lesion area of ​​the laser pattern, and performs a pre-set triangulation relationship based on the laser projection module and the image acquisition module to map the two-dimensional image points onto the corresponding three-dimensional laser plane;

[0042] 3D coordinate construction module: converts the subpixel coordinates of the lesion area into 3D spatial coordinates, the 3D spatial coordinates including the X-axis iris lesion diameter, the Y-axis iris lesion height, and the Z-axis iris lesion spacing;

[0043] Geometric parameter measurement module: Based on the three-dimensional spatial coordinates, calculate the geometric parameters of the lesion area, including the lesion area and the curvature of the lesion area.

[0044] The laser projection module generates a structured laser beam and projects it onto the surface of the iris of the eye to be tested, thereby forming an optical pattern that modulates the iris surface morphology.

[0045] A1: Laser emission and preliminary collimation;

[0046] Turn on the laser source and connect the drive circuit to enable the low-power, visible near-infrared semiconductor laser diode (LD) to work. For laser wavelength selection, prioritize red laser of 635nm-650nm or near-infrared laser of 780nm-850nm. Red laser is easier to observe and adjust with the naked eye, while near-infrared laser is less irritating to patients and is invisible to the human eye, making it safer.

[0047] Laser power constraints: The laser output power must be strictly limited to Class I or Class II laser safety standards to ensure that it will not cause damage to the eyes under any circumstances. The power is usually below 1mW.

[0048] Further explanation is needed regarding the Class I or Class II laser safety standards. Class I lasers are safe for use under normal conditions and pose no harm to the human eye and skin. Their power is typically extremely low (≤0.39mW in the visible light band) and their wavelength range covers 180nm to 1mm. Class II lasers are limited to visible light in the 400-700nm band and have a power ≤1mW. They protect the eyes through the human blink reflex time (approximately 0.25 seconds).

[0049] Initial beam collimation: The beam emitted by the laser diode has a large divergence angle, so a collimating lens is needed to convert the diverging beam into an approximately parallel beam, forming a small, uniform spot. This process is the basis for generating high-quality structured light.

[0050] A2: Beam structuring;

[0051] Based on the required accuracy and range for measuring iris lesions, a grid laser (two-dimensional measurement surface) is selected. A first cylindrical mirror is inserted into the collimated circular spot optical path, and a beam splitter and a second cylindrical mirror (perpendicular to the first cylindrical mirror) are added. Using a diffractive optical element (DOE), the collimated laser beam is directly irradiated onto a specially designed DOE. The DOE, through its surface micro / nano structure, diffracts the incident laser into a preset pattern (e.g., a dot matrix, grid, or circular spot).

[0052] A3: Projection and Focusing;

[0053] Beam transmission involves adjusting the optical path direction of a reflector or prism to direct the shaped structured laser beam towards the eye being tested. The beam then passes through a projection lens group, whose functions are: to control the working distance between the laser beam and the eye (10–50 mm from the cornea) so that the laser pattern can be clearly imaged on the iris surface; to ensure that the generated laser pattern can completely cover the entire iris area, and even part of the sclera; and to precisely project the beam by adjusting the position and angle of the entire module so that the final clear laser pattern (such as a thin line or a grid) accurately covers the iris surface of the patient's eyeball.

[0054] A4: Forming a modulation pattern;

[0055] Surface morphology modulation: When a structured light pattern is projected onto a non-planar iris surface, the originally regular optical pattern will be distorted due to the presence of lesions (such as cysts, nodules, and depressions).

[0056] For linear lasers, a straight laser line will bend forward (protrusion) when it encounters a raised lesion and bend backward (depression) when it encounters a depressed lesion. The height information of the iris on that cross section can be determined based on the protrusion and depression values.

[0057] For grid light, the regular grid will produce uneven distortion and stretching due to surface undulations. This distortion contains rich three-dimensional morphological information of the entire iris region. The modulated optical pattern formed on the iris surface at this time is the target that the image acquisition module needs to capture. The difference between the modulated pattern and the original regular pattern corresponds to the geometric shape of the lesion.

[0058] The image acquisition module acquires an image of the modulated laser pattern on the iris surface based on a fixed angle formed by the optical axis and the laser projection module.

[0059] B1: Establish spatial geometric relationships;

[0060] Physical fixation and angle preset fix the image acquisition module (camera) and laser projection module on the same platform (such as a metal bracket);

[0061] The angle between the camera's optical axis and the laser projection module's optical axis is precisely adjusted; this is the baseline angle for triangulation. The angle range is controlled between 15° and 30°, and is preset based on the measurement distance, accuracy requirements, and field of view. At the same distance, the larger the angle, the higher the sensitivity of the lesion spacing (Z-axis) measurement, but it may cause occlusion problems. The smaller the angle, the more compact the measurement, but the lower the resolution of the lesion spacing.

[0062] B2: Configure image acquisition hardware;

[0063] Choose a monochrome CMOS or CCD area array camera. Monochrome cameras avoid the resolution loss caused by Bayer filtering and are more sensitive to monochrome laser light. The resolution of the selected camera needs to be above 2 million pixels to facilitate subsequent sub-pixel level feature point extraction.

[0064] Choose a fixed-focus lens to ensure image stability and consistency. The focal length is determined based on the iris measurement distance and field of view size. Install a narrow-band bandpass filter in front of the fixed-focus lens, with its center wavelength strictly matched to the laser wavelength of the laser projection module (e.g., for a 650nm laser, use a filter with a center wavelength of 650nm and a bandwidth of ±10nm). The filter greatly suppresses ambient stray light (such as operating room lighting), allowing only the laser pattern to pass through efficiently, thus forming high-contrast laser stripes on the image.

[0065] B3: Optical Focusing and Parameter Settings;

[0066] Focus by aligning the camera with the model eye or calibration target and finely adjusting the lens focal length to ensure that the iris area and the projected laser pattern are most clearly imaged at the expected iris measurement distance (e.g., 50mm in front of the cornea).

[0067] Set the camera parameters and a short exposure time of 1-10ms to ensure that the laser pattern is clearly visible without blurring due to patient eye movement or body movement; due to the use of a narrow-band filter and the brightness of the laser itself, there is no need to perform high-gain processing on the laser; appropriately reduce the aperture (e.g., f / 4-f / 8) to ensure that the laser pattern on the entire iris surface is within the measurement range;

[0068] B4: Image capture;

[0069] Once the patient is in position and maintains fixation, the system issues a command to perform synchronous image acquisition, transmitting the single-frame grayscale image captured by the camera at high speed to the computer's data processing module via a data interface (such as USB 3.0); the image contains a clear, bright, distorted laser pattern against a dark background (the natural texture of the iris suppressed by the filter and ambient light).

[0070] The data processing module processes the image of the laser pattern, extracts the sub-pixel coordinates of the lesion area of ​​the laser pattern, and pre-sets the triangulation relationship based on the laser projection module and the image acquisition module to map the two-dimensional image points onto the corresponding three-dimensional laser plane.

[0071] C1: Image preprocessing is used to enhance the signal-to-noise ratio;

[0072] The captured single-frame grayscale image is directly read from the image acquisition module; the input single-frame grayscale image is corrected using a pre-acquired background image (only for uniformly illuminated irises) and a planar image (projecting the original unmodulated laser pattern onto a white diffuse plane). Gaussian filtering or median filtering algorithms are used to suppress random noise in the image (such as CMOS thermal noise) while preserving the edge information of the laser stripes as much as possible to eliminate the effects of camera dark noise and uneven illumination.

[0073] C2: Laser stripe and pattern area segmentation to locate the lesion area;

[0074] Dynamic threshold segmentation is used because ambient light is greatly suppressed, and the laser pattern is usually the brightest area in the image. A fixed threshold method is used to create a binary mask to separate the bright laser pixels from the background image.

[0075] The lesion area is focused, and morphological opening operations are used to remove tiny noise points. Based on the continuity of the laser pattern, areas that have undergone significant distortion, breakage or deformation due to lesion modulation are identified. These areas are the preliminary candidate areas for the lesion area.

[0076] C3: Subpixel-level coordinate extraction;

[0077] The grayscale centroid method is used to process the grayscale distribution of each laser stripe cross-section. The specific calculation formula for grayscale distribution processing is as follows: ,in Indicates the subpixel center corresponding to the laser stripe coordinate, Represents the grayscale value of the i-th pixel. Represents the i-th pixel The coordinates, after calculation, yield a set of ordered sub-pixel precision two-dimensional coordinate points. These points precisely describe the shape of the modulated laser stripes in the image;

[0078] Lesion area identification and coordinate association involve comparing the extracted distorted laser stripes with reference laser stripes acquired on a standard plane. By calculating the offset between the two stripe lines, distorted segments are identified, which correspond to lesion areas (protrusions or depressions) on the iris surface. A point set of lesion areas is extracted, and those sub-pixel coordinate points whose deviation from the reference line exceeds a preset threshold are identified. Mark them out as sub-pixel coordinates of the lesion area;

[0079] C4: Preset triangulation relationships and 3D mapping;

[0080] The pre-set triangulation relationship mainly involves loading calibration parameters, which include: camera intrinsic parameter matrix K and laser plane equation. Camera distortion coefficients D; where the camera intrinsic parameter matrix ,in express The equivalent focal length in the horizontal direction describes the camera's scaling capability. express The equivalent focal length in the vertical direction describes the camera's scaling capability. Indicates the horizontal pixel coordinates of the principal point (center of the optical axis). Represents the vertical pixel coordinates of the principal point (center of the optical axis);

[0081] Laser plane equation This means that the laser emitted by the laser projection module forms a plane (optical plane). In the camera coordinate system (a three-dimensional coordinate system with the camera's optical center as the origin, the X-axis to the right, the Y-axis downwards, and the Z-axis forwards), the equation of this plane is usually expressed as: Where A, B, C, and D represent the coefficients (constants) of the plane equation, which determine the position and orientation of the laser plane in the camera coordinate system;

[0082] The camera distortion coefficient D represents the extracted subpixel image coordinates. Corrected to distortion-free ideal pixel coordinates The corrected subpixel image coordinates are back-projected onto the camera coordinate system using camera intrinsic parameters, forming a ray originating from the camera's optical center. This ray intersects with the preset laser plane equation. Perform the intersection calculation; the specific calculation formula is as follows: Where P represents the direction vector of the ray and T represents the matrix transpose;

[0083] By performing intersection calculations, a point in the image can be... This is mapped to a specific point in three-dimensional space that falls on the laser plane; these points correspond to the three-dimensional coordinates of lesion feature points in the image. .

[0084] The three-dimensional coordinate construction module converts the sub-pixel coordinates of the lesion region into three-dimensional spatial coordinates, which include the X-axis iris lesion diameter, the Y-axis iris lesion height, and the Z-axis iris lesion spacing.

[0085] D1: Receive 3D point coordinates ;

[0086] Receive the three-dimensional point coordinates of the lesion area in the camera coordinate system from the data processing module. These points are all precisely located on the previously calibrated laser plane, representing all three-dimensional points in the lesion area. Transform to the iris coordinate system to obtain the new coordinates. ,in Indicates the horizontal position of the point on the iris plane. Indicates the vertical position of the point on the iris plane. Indicates the height of the point relative to the iris reference plane. Indicates a raised area Indicates a depression;

[0087] D2: Calculate the diameter of the iris lesion on the X-axis, the height of the iris lesion on the Y-axis, and the distance between the iris lesions on the Z-axis in three-dimensional spatial coordinates;

[0088] The X-axis diameter of the iris lesion is calculated by projecting all lesion points onto the iris reference plane. ;

[0089] The Y-axis iris lesion height, where height usually refers to the degree of protrusion or depression of the lesion, i.e. Change ;

[0090] The Z-axis iris lesion spacing is the distance between the center points of the lesion areas. The absolute value of the coordinates represents the average depth of the entire lesion relative to the iris reference plane. This refers to the average depth of the lesion.

[0091] The geometric parameter measurement module calculates the geometric parameters of the lesion region based on the three-dimensional spatial coordinates. These geometric parameters include the lesion area and the lesion curvature.

[0092] E1: Receive new coordinates from D1 Calculate the area of ​​the lesion;

[0093] The lesion area refers to the actual surface area of ​​the lesion area in three-dimensional space; triangular mesh construction uses the Delaunay triangulation algorithm to connect discrete three-dimensional coordinate points into a continuous triangular mesh. This mesh is a geometric approximation of the lesion surface, which can be simply understood as covering the iris lesion surface with countless tiny triangles.

[0094] At this point, calculating the surface area of ​​the triangular mesh yields the area of ​​the lesion region. This is based on triangles formed by the coefficients (constants) of the equations for planes A, B, C, and D; the area of ​​each triangle is then calculated. The total surface area of ​​the lesion area is obtained by summing the faces of all the triangles.

[0095] E2: Receive new coordinates from D1 Calculate the curvature of the lesion area;

[0096] Curvature quantifies the degree of curvature of a surface at a point. Calculating the curvature of a lesion area can determine whether it is a sharp protrusion, a gentle bulge, or a depression, which is of great value in the diagnosis of ocular lesions (such as cysts, tumors, and pigmented nevi). Curvature is usually calculated in two ways: Gaussian curvature and mean curvature. Mean curvature is used to estimate the curvature of a three-dimensional coordinate point. This is done by calculating the difference between the position of the vertex of the triangle formed by the coefficients (constants) of the equations of planes A, B, C, and D and the positions of the other adjacent vertices, thus estimating the inherent curvature of the surface at that point. Taking vertex A as an example, the specific curvature calculation formula is as follows:

[0097]

[0098] in A represents the average curvature of a vertex, and A represents the area of ​​influence of that vertex. This represents the cotangent value of the angle between vertex A and the adjacent edges i and j. This calculation will output a curvature value for each vertex in the lesion area. By estimating the sum of the curvature values ​​of the iris lesion area, the curvature of the lesion area is obtained.

[0099] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0100] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for measuring the geometric parameters of iris lesions based on laser triangulation, characterized in that, The application relates to a laser projection module, an image acquisition module, a data processing module, a three-dimensional coordinate construction module and a geometric parameter measurement module. The laser projection module generates a structured laser beam from a laser and projects the laser beam to an iris surface of an eye to be measured to form a laser pattern modulated by the surface topography of the iris. The image acquisition module acquires an image of the laser pattern modulated by the iris surface based on a fixed included angle formed by an optical axis and the laser projection module. The data processing module processes the image of the laser pattern, extracts sub-pixel coordinates of a lesion area of the laser pattern, and maps two-dimensional image points to corresponding three-dimensional laser planes based on a preset triangulation relationship between the laser projection module and the image acquisition module. The mapping of the two-dimensional image points to corresponding three-dimensional laser planes comprises presetting a triangulation relationship as loading calibration parameters, the calibration parameters comprising a camera intrinsic parameter matrix K, a laser plane equation , and a camera distortion coefficient D; and the two-dimensional image points are mapped to corresponding three-dimensional laser planes through intersection calculation of the laser plane equation . The three-dimensional coordinate construction module converts the sub-pixel coordinates of the lesion area into three-dimensional space coordinates, and the three-dimensional space coordinates include an X-axis iris lesion diameter, a Y-axis iris lesion height and a Z-axis iris lesion spacing. The geometric parameter measurement module calculates geometric parameters of the lesion area based on the three-dimensional space coordinates, and the geometric parameters include a lesion area and a lesion curvature.

2. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 1, wherein, The laser projection module includes a near-infrared semiconductor laser diode or a red semiconductor laser diode, the wavelength range of the near-infrared laser is 780nm-850nm, the wavelength range of the red laser is 635nm-650nm, the output power of the laser meets the I-class or II-class laser safety standard, and the power is not more than 1mW. The laser projection module generates a structured laser beam from a laser and projects the laser beam to an iris surface of an eye to be measured to form a laser pattern modulated by the surface topography of the iris.

3. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 2, wherein, The structured laser is formed by a diffraction optical element or a double-cylindrical lens combination, the pattern of the structured laser is a grid, a dot array or a linear stripe, the working distance of the laser projection module and the cornea is 10-50mm, and the structured laser pattern projected covers the whole iris area. The image acquisition module includes 4. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 1, wherein, The processing of the image of the laser pattern includes background correction, flat field correction and Gaussian filtering, and the gray distribution of each laser stripe cross section segmented is processed by a gray center method, so that the sub-pixel coordinates of the lesion area are extracted. According to the iris measurement distance, accuracy requirements and field of view range, the included angle range is controlled to , the image acquisition component is configured for optical focusing and parameter setting, used for collecting the modulated laser pattern, and the exposure time is set to 1-10 ms, and the aperture adjustment range is f / 4-f / 8.

5. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 1, wherein, The three-dimensional coordinate construction module includes Coordinate system conversion: the three-dimensional point cloud data of the lesion area in a camera coordinate system is converted to an iris coordinate system with an iris reference plane as a reference; 6. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 1, wherein, Geometric size calculation: the projection diameter of the lesion area in the X-axis direction is calculated as the lesion diameter, the height extreme value of the lesion point relative to the reference plane is calculated as the lesion height, and the average depth absolute value of the center point of the lesion area is calculated as the lesion spacing. The geometric parameter measurement module calculates the lesion area and includes The Delaunay triangulation algorithm is adopted to convert the three-dimensional coordinate points of the lesion area into a triangular mesh, and the area of the triangular mesh is accumulated to obtain the lesion area; the area of the triangular mesh is calculated by a laser plane equation.

7. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 1, wherein, The geometric parameter measurement module calculates the lesion curvature and includes The average curvature formula is adopted to estimate the curvature of each vertex and the adjacent vertex in the three-dimensional coordinate points of the lesion area, and the curvature values of the vertices are accumulated to obtain the lesion curvature.

8. The laser triangulation based system for measuring geometric parameters of lesions in iris according to claim 1, wherein, ​ ​

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