CN-122004738-A - Method and system for measuring optical coherence tomography image of anterior ocular segment

CN122004738ACN 122004738 ACN122004738 ACN 122004738ACN-122004738-A

Abstract

The invention belongs to the technical field related to anterior ocular segment image measurement, and aims to solve the problems of poor scanning adaptation, low signal to noise ratio and the like in the existing anterior ocular segment imaging, and provides an anterior ocular segment optical coherence tomography image measurement method and system, wherein an acquisition beam along the optical axis direction of the anterior ocular segment is adopted to pre-scan the anterior ocular segment, an anterior ocular segment tomography image acquired along the optical axis direction is scanned, and the theoretical boundary position of the anterior ocular segment under an axial detection signal is determined in a data fitting mode; the method comprises the steps of correcting theoretical boundary positions of the anterior ocular segment under an axial detection signal by considering optical path differences of different scanning positions of the anterior ocular segment, obtaining an actual boundary curve of the anterior ocular segment under the axial detection signal, carrying out equidistant scanning on the surface of the anterior ocular segment along the normal direction of the actual boundary curve, recovering the flattened anterior ocular segment boundary based on the anterior ocular segment tomographic images acquired under the equidistant scanning in the normal direction, and realizing high-quality imaging of the anterior ocular segment OCT images.

Inventors

SONG WEIYE
WANG YUKUAN
ZHOU LIBO
CUI YUAN
QI MIN
WU FUWANG
LU XIAOQI
SHENG PENG

Assignees

山东大学

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (15)

1. A method of measuring an optical coherence tomographic image of an anterior segment of an eye, comprising: pre-scanning the anterior ocular segment by using an acquisition light beam along the optical axis direction of the anterior ocular segment, and acquiring an anterior ocular segment tomographic image; determining the theoretical boundary position of the anterior ocular segment under the axial detection signal by a data fitting mode for the anterior ocular segment tomographic image which is scanned and collected along the optical axis direction of the anterior ocular segment; Correcting the theoretical boundary position of the lower anterior ocular segment of the axial detection signal by considering the optical path differences of different scanning positions of the anterior ocular segment to obtain an actual boundary curve of the lower anterior ocular segment of the axial detection signal; Equidistant scanning is carried out on the surface of the anterior segment along the normal direction of an actual boundary curve, and an anterior segment tomographic image formed by axial detection signals of a plurality of acquisition positions of the anterior segment is obtained; and recovering the flattened anterior ocular segment boundary based on the anterior ocular segment tomographic image acquired under equidistant scanning in the normal direction, so as to realize high-quality imaging of the anterior ocular segment optical coherence tomographic image.
2. A method for measuring an optical coherence tomographic image of an anterior segment of an eye according to claim 1, wherein the anterior segment of the eye is pre-scanned by an acquisition beam along the optical axis of the anterior segment of the eye, and the anterior segment tomographic image is acquired by: Repeatedly scanning the anterior ocular segment by using an acquisition light beam along the optical axis direction of the anterior ocular segment to obtain a plurality of anterior ocular segment tomographic images; and carrying out registration averaging on the plurality of anterior ocular segment tomographic images to obtain a final anterior ocular segment tomographic image under parallel optical axis scanning.
3. A method of measuring an optical coherence tomographic image of an anterior segment of an eye as claimed in claim 1 or 2, wherein the axial detection signals included in the tomographic image of the anterior segment of an eye acquired by scanning in the optical axis direction are subjected to peak extraction, and the index of the first one of the axial detection signals representing the peak pixel of the structure is selected as the anterior boundary point of the cornea.
4. The method for measuring an optical coherence tomography image of an anterior segment of an eye according to claim 1, wherein coordinates of a boundary point of the anterior segment of the eye corresponding to each axial detection signal under the OCT system are calculated according to a coordinate mapping relation in which a pixel coordinate system of the optical coherence tomography image of the anterior segment of the eye, which is scanned and collected along an optical axis direction, is mapped to an OCT system coordinate system, and theoretical boundary positions of the anterior segment of the eye under the axial detection signals are determined by a least square method according to the coordinates of the boundary point of the anterior segment of the cornea corresponding to each axial detection signal under the OCT system.
5. The method for measuring an optical coherence tomography image of an anterior ocular segment according to claim 1, wherein the theoretical boundary position of the anterior ocular segment under the axial detection signal is corrected by considering the optical path differences of different scanning positions of the anterior ocular segment to obtain an actual boundary curve of the anterior ocular segment under the axial detection signal, specifically: Determining the extra optical path difference of the axial detection beams at different scanning positions relative to the optical axis of the anterior segment according to the included angles of the axial detection beams at different scanning positions of the anterior segment and the optical axis of the anterior segment and the focal length of the beam refraction lens; and correcting the theoretical boundary position of the anterior ocular segment under the axial detection signal according to the extra optical path difference to obtain an actual boundary curve of the anterior ocular segment under the axial detection signal.
6. The method for measuring an optical coherence tomography image of an anterior segment of an eye according to claim 1, wherein the whole imaging range is divided into a plurality of equally spaced boundary points based on an actual boundary curve of the anterior segment of the eye, an external normal direction of an actual anterior segment boundary at each boundary point is obtained, acquisition positions are determined at equal distances from a focal length of a lens of the anterior segment along the external normal direction, and all the acquisition positions are determined by traversing all the boundary points to form an acquisition path.
7. The method for measuring an optical coherence tomography image of an anterior segment of an eye according to claim 1, wherein when equidistant scanning is performed on the anterior segment of the eye along a normal direction, repeated acquisition is performed for each acquisition position, and an axial detection signal acquired for each acquisition position is averaged in time, space and signal phase to obtain a high signal-to-noise ratio axial detection signal for the corresponding acquisition position.
8. A method for measuring optical coherence tomography images of anterior ocular segments as recited in claim 7, wherein the repeated acquisition is performed for each acquisition location a plurality of times, in particular: taking a point intersecting the whole acquisition path along the normal direction of the practical anterior segment boundary curve as a main acquisition point; and setting a plurality of auxiliary acquisition points after the main acquisition points are consistent in direction and the spatial positions are translated, and respectively carrying out repeated acquisition on the main acquisition points and the auxiliary acquisition points, wherein the direction of the main acquisition points is along the normal direction of the boundary points corresponding to the practical anterior segment boundary curve.
9. A method for measuring an optical coherence tomographic image of an anterior segment of an eye as in claim 1, wherein the imaging angles of different acquisition positions are added to the image reconstruction to sequentially rotate the acquisition images along the last line position by the acquisition angles to achieve high quality imaging of the optical coherence tomographic image of the anterior segment of an eye.
10. A method for measuring optical coherence tomography of the anterior segment of the eye according to claim 1 or 9, characterized in that the reconstruction of the tomographic image of the anterior segment acquired under equidistant scanning along the normal direction is performed by: Wherein, the And Representing the column and row values in the pixel coordinates of the original scanned image formed by the high signal-to-noise ratio axial detection signals, wherein i represents the high signal-to-noise ratio axial detection signal of the ith acquisition position; And Values representing columns and rows of reconstructed pixel coordinates; the number of the pixel units of the linear array camera of the spectrometer for optical coherence tomography; representing an imaging included angle of the ith acquisition position; The method comprises the steps of (1) acquiring the abscissa of an ith A-Line cornea anterior boundary point under a system coordinate; Is the actual anterior ocular segment boundary curve.
11. A method for measuring an optical coherence tomographic image of an anterior segment of an eye according to claim 4, wherein the system imaging depth is calculated by detecting a center wavelength of the beam, an air refractive index, and a spectral sampling resolution, and pixel coordinates of the tomographic image of the anterior segment of an eye acquired by scanning in the optical axis direction are mapped to OCT system coordinates according to the system imaging depth.
12. An anterior ocular segment optical coherence tomography image measurement system, comprising: a pre-scanning module configured to pre-scan an anterior ocular segment with an acquisition beam along an optical axis direction of the anterior ocular segment, acquire an anterior ocular segment tomographic image; The calculation module is configured to determine the theoretical boundary position of the anterior ocular segment under the axial detection signal by a data fitting mode for the anterior ocular segment tomographic image which is scanned and acquired along the optical axis direction of the anterior ocular segment; The correction module is configured to correct the theoretical boundary position of the lower anterior ocular segment of the axial detection signal by considering the optical path differences of different scanning positions of the anterior ocular segment to obtain an actual boundary curve of the lower anterior ocular segment of the axial detection signal; The scanning module is configured to carry out equidistant scanning on the surface of the anterior ocular segment along the normal direction of the actual boundary curve to obtain an anterior ocular segment tomographic image formed by axial detection signals of a plurality of acquisition positions of the anterior ocular segment; And the imaging module is configured to recover the flattened anterior ocular segment boundary based on the anterior ocular segment tomographic image acquired under equidistant scanning in the normal direction, so as to realize high-quality imaging of the anterior ocular segment optical coherence tomographic image.
13. An electronic device comprising a memory and a processor and computer instructions stored on the memory and running on the processor, which when executed by the processor, perform the method of any one of claims 1-11.
14. A computer readable storage medium storing computer instructions which, when executed by a processor, perform the method of any of claims 1-11.
15. A computer program product comprising a computer program which, when executed by a processor, implements the method of any of claims 1-11.

Description

Method and system for measuring optical coherence tomography image of anterior ocular segment Technical Field The invention belongs to the technical field of anterior ocular segment image measurement, and particularly relates to an anterior ocular segment optical coherence tomography image measurement method and system. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. Optical Coherence Tomography (OCT) is a technique that uses weak interference signals to make three-dimensional measurements of a sample. The intensity of the OCT measurement signal is related to the angle of the incident light, and the intensity of the back scattered light beam is stronger when the incident light is perpendicular to the surface to be measured, so that the interference intensity of the spectrum of the sample and the spectrum of the reference arm is improved. The high-quality OCT imaging of the anterior ocular segment can noninvasively quantify key structural parameters such as cornea, anterior chamber, atrial angle, crystalline lens and the like, is a core basis for glaucoma screening, angle closure risk assessment, ICL implantation preoperative planning, keratopathy diagnosis, cataract assessment and follow-up visit after refractive surgery, and provides objective imaging guarantee for accurate diagnosis and treatment and surgery safety. The existing detection methods are all one-time imaging through a fixed point position large-view-field scanning method, and the imaging signal-to-noise ratio is improved through a multi-frame averaging method. However, the curvature radius of the anterior segment of the eye of the individual can reach 7.0-9.5 mm, the shape (sphere, aspheric surface and symmetry) of the anterior segment is huge, and the return interference signals of the light rays at the places with weak reflection signals such as cornea and the like in a fixed scanning mode are directly influenced, so that the signal-to-noise ratio of part of the positions is obviously reduced, and the internal structure cannot be effectively observed. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a method and a system for measuring the optical coherence tomography image of the anterior segment of the eye, which realize the high-quality imaging of the optical coherence tomography image of the anterior segment of the eye. In order to achieve the above purpose, the present invention adopts the following technical scheme: in a first aspect, the present invention provides a method of optical coherence tomography of the anterior segment of the eye, comprising: pre-scanning the anterior ocular segment by using an acquisition light beam along the optical axis direction of the anterior ocular segment, and acquiring an anterior ocular segment tomographic image; determining the theoretical boundary position of the anterior ocular segment under the axial detection signal by a data fitting mode for the anterior ocular segment tomographic image which is scanned and collected along the optical axis direction of the anterior ocular segment; Correcting the theoretical boundary position of the lower anterior ocular segment of the axial detection signal by considering the optical path differences of different scanning positions of the anterior ocular segment to obtain an actual boundary curve of the lower anterior ocular segment of the axial detection signal; Equidistant scanning is carried out on the surface of the anterior segment along the normal direction of an actual boundary curve, and an anterior segment tomographic image formed by axial detection signals of a plurality of acquisition positions of the anterior segment is obtained; and recovering the flattened anterior ocular segment boundary based on the anterior ocular segment tomographic image acquired under equidistant scanning in the normal direction, so as to realize high-quality imaging of the anterior ocular segment optical coherence tomographic image. In a second aspect, the present invention provides an optical coherence tomography image measurement system for anterior ocular segments, comprising: a pre-scanning module configured to pre-scan an anterior ocular segment with an acquisition beam along an optical axis direction of the anterior ocular segment, acquire an anterior ocular segment tomographic image; The calculation module is configured to determine the theoretical boundary position of the anterior ocular segment under the axial detection signal by a data fitting mode for the anterior ocular segment tomographic image which is scanned and acquired along the optical axis direction of the anterior ocular segment; The correction module is configured to correct the theoretical boundary position of the lower anterior ocular segment of the axial detection signal by considering the optical path differences of different scanning posi