OCT imaging system and method based on dual deformable mirror and digital micromirror array

Abstract

The application belongs to the field of ophthalmic medical imaging equipment, and provides an OCT imaging system and method based on a double deformable mirror and a digital micromirror array, which comprises a beacon light source module, a tracking imaging module, a retinal functional imaging module, a double galvanometer adjustment module, a double deformable mirror adjustment module and a control module; the application proposes a high-resolution functional adaptive optical coherence tomography imaging system for non-cooperative targets, adopts FSM to actively adapt the optical path to the eyeball, and can take clear images without anesthesia; the application automatically adapts to the huge refractive difference from infants to adults without external inserts; and the application uses light stimulation to induce retinal physiological signals, and diagnoses diseases through functional abnormalities before cell apoptosis.

Description

Technical Field

[0001] This invention pertains to ophthalmic medical imaging equipment, specifically relating to an OCT imaging system and method based on a dual deformable lens and a digital micromirror array. Background Technology

[0002] Existing commercial OCT and research-grade AO-OCT equipment face four major obstacles in clinical application: 1. Uncontrolled eye movements leading to imaging failure: Current equipment requires patients to fixate on a light for extended periods. However, children (especially hyperactive or young children) or patients with nystagmus cannot maintain a stable gaze, exhibiting frequent microsaccades and significant eye drift. Traditional equipment easily loses track of the target, resulting in image fragmentation and blurring.

[0003] 2. Diagnostic blind spot: Normal retinal structure but poor vision. Many hereditary eye diseases (such as early retinitis pigmentosa, color blindness, and retinopathy of prematurity) present with intact retinal structure and morphology in their early stages, but cell function has already been lost. Current OCT can only assess structure, not function. Doctors cannot make a diagnosis during the window of opportunity before cell death, leading to missed opportunities for gene therapy.

[0004] 3. Extremely wide range of refractive errors, making correction difficult: Children's eyes are still developing, and there are huge differences in axial length, which may result in extremely high hyperopia, myopia, or astigmatism. The single deformable lens of the existing AO system has a limited travel, and it is usually necessary to insert a trial lens in front of the patient's eyes for pre-correction, which is a cumbersome procedure.

[0005] 4. Early, minute lesions are not visible: Standard OCT has insufficient resolution and cannot distinguish individual photoreceptor cells. In cases of congenital genetic diseases, when doctors can see thinning of the retina on a standard OCT scan, it often means that a large number of cells have already died. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an OCT imaging system and method based on a dual deformable mirror and a digital micromirror array, thereby resolving the issues in the prior art. The technical solution adopted by this invention is as follows: An OCT imaging system based on dual deformable mirrors and a digital micromirror array includes: The beacon light source module is used to emit beacon light for subsequent wavefront aberration detection and eye movement tracking. The tracking imaging module is used to receive beacon light reflected from the fundus; one path of the beacon light is used to measure intraocular aberrations through a wavefront sensor; the other path of the beacon light is used to monitor eye movement in real time through a tracking camera and perform closed-loop image stabilization to eliminate the influence of eye tremors on imaging. The retinal functional imaging module is used to generate light stimulation signals and project them onto the retina to induce photophysiological responses. Dual galvanometer adjustment module: including XY scanning galvanometer group and FSM fast control mirror; wherein, the XY scanning galvanometer group is used to perform two-dimensional raster scanning of OCT imaging beam and stimulation beam to cover the retinal imaging area; the FSM fast control mirror performs real-time motion compensation based on eye tracking signal; The dual deformable mirror adjustment module is used to receive aberration data from the wavefront sensor and perform wavefront correction on the incident imaging light and stimulus light through dual mirror linkage. The control module is used to: receive feedback signals from the tracking imaging module and calculate correction values ​​through algorithms; send scanning commands to the dual galvanometer module; send scanning commands to the dual galvanometer adjustment module; send voltage control signals to the dual deformable mirror adjustment module to change the mirror shape; control the retinal functional imaging module to generate light stimulation signals and simultaneously acquire OCT signals.

[0007] Furthermore, the beacon light source module includes a narrowband light source and matching collimating optical elements.

[0008] Furthermore, the tracking imaging module includes a wavefront sensor, an eye-tracking camera, and an FSM fast-control mirror.

[0009] Furthermore, the retinal functional imaging module includes a DMD digital micromirror array, a red monochromatic light source, a green monochromatic light source, a blue monochromatic light source, and a projection optical path.

[0010] Furthermore, the dual deformable mirror adjustment module includes a Woofer deformable mirror and a Tweeter deformable mirror.

[0011] A closed-loop image stabilization method includes the following steps: Step S1: Reference Frame Selection and ROI Locking: When the system starts up, it first acquires an image frame as a reference frame at the moment when the eye is relatively still; and selects high-contrast retinal blood vessels or optic disc features as regions of interest in the reference frame. Step S2: Real-time displacement calculation: The tracking camera acquires the current frame image in real time; a normalized cross-correlation algorithm or a subpixel-level phase correlation algorithm based on FFT is used; a fast Fourier transform is performed on the region of interest of the reference frame and the current frame; then the cross power spectrum is calculated; then an inverse Fourier transform is performed to obtain the correlation peak; the peak position of the correlation peak is fitted by a Gaussian surface to calculate the horizontal and vertical displacement of the current frame relative to the reference frame. Step S3: PID closed-loop control: The calculated horizontal and vertical displacements are input as error signals to the PID controller; Step S4: FSM driver execution: The control module converts the control quantity output by the PID controller into an analog voltage signal; drives the FSM to quickly control the piezoelectric ceramic or voice coil motor actuator of the reflector, causing it to deflect slightly in the horizontal and vertical directions; the deflection of the FSM changes the optical path angle, so that the point where the incident beam lands on the retina always coincides with the position of the reference frame, thereby physically canceling eye movement and achieving image locking.

[0012] A wavefront correction method includes the following steps: Step S1: Obtaining full-order wavefront aberrations: The raw wavefront data measured by the wavefront sensor is reconstructed into a set of Zernike polynomial coefficients: ; Step S2: Aberration task assignment: Set the partitioning order N=5 or N=10; then set the order... Zernike coefficient to Assign to the Woofer deformable mirror; change the order Zernike coefficient to Assigned to the Tweeter morphing mirror; Step S3: Voltage calculation based on the influence matrix: Establish the influence matrices for the Woofer and Tweeter deformable mirrors: and ; Obtain the voltage vector of the Woofer deformable mirror: ; Obtain the voltage vector of the Tweeter deformable mirror: ; in, and These are vectors composed of low-order and high-order aberration coefficients, respectively.

[0013] The present invention has the following beneficial effects: (1) The passive movement of the eyeball is compensated by the active movement of the optical element. Even if the child's eyeball has high-frequency nystagmus, the light spot projected onto the retina remains stationary, completely solving the problems of blurry images and loss of focus; (2) In this invention, the Woofer performs the function of a traditional eyeglass lens, and the Tweeter performs the function of a microscope. This allows the system to directly image children with refractive errors ranging from -10D to +10D without the need for additional trial lenses, greatly simplifying the clinical operation process. Attached Figure Description

[0014] Figure 1 This is a simplified structural diagram of the present invention; Figure 2 This is the optical path diagram of the present invention; In the diagram: OCT light source 1-1; optical isolator 1-2; first collimator 2-1; glass block 2-2; focusing lens 2-3; motorized mirror 2-4; fiber optic coupler 3; spectrometer 4; beacon light source 5-1; optical isolator 5-2; mirror 5-3; second collimator 5-4; first dichroic mirror 5-5; second dichroic mirror 5-6; first 4F system 5-7; wavefront sensor 5-8; third dichroic mirror 5-9; 4F system 5-10; eye-tracking camera 5-11; FSM fast-control mirror 5-12; relay lens 5-13; XY scanning galvanometer group 5-14; fourth dichroic mirror 5-15; 4F system 5-16 ; DMD digital micromirror array device 5-17; second 4F system 5-18; light-diffusing bar 5-19; fifth dichroic mirror 5-20; third optical shutter 5-21; blue monochromatic light source 5-22; second dichroic mirror 5-23; first optical shutter 5-24; green monochromatic light source 5-25; second optical shutter 5-26; red monochromatic light source 5-27; third 4F system 5-28; Woofer deformable mirror 5-29; fourth 4F system 5-30; Tweeter deformable mirror 5-31; mirror 5-32; second focusing lens 5-33; fifth 4F system 5-34; safety shutter 5-35; sample 5-36. Detailed Implementation

[0015] The following will be described in conjunction with embodiments of the present invention. Figures 1-2 The technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0016] This invention proposes an OCT imaging system based on a dual deformable mirror and a digital micromirror array, comprising: The beacon light source module is used to emit beacon light for subsequent wavefront aberration detection and eye movement tracking. The tracking imaging module is used to receive beacon light reflected from the fundus; one path of the beacon light is used to measure intraocular aberrations through a wavefront sensor; the other path of the beacon light is used to monitor eye movement in real time through a tracking camera and perform closed-loop image stabilization to eliminate the influence of eye tremors on imaging. The retinal functional imaging module is used to generate light stimulation signals and project them onto the retina to induce photophysiological responses. The dual-galvanometer adjustment module includes an XY scanning galvanometer group 5-14 and an FSM fast-control mirror 5-12, as well as a matching relay lens 5-13 (4F system). The XY scanning galvanometer group 5-14 is used to perform two-dimensional raster scanning of the OCT imaging beam and the stimulation beam to cover the retinal imaging area. The FSM fast-control mirror 5-12 performs real-time motion compensation based on eye-tracking signals to eliminate the impact of nystagmus on image quality. It is located at the hub of the optical path and is responsible for performing two-dimensional raster scanning of the imaging beam and the stimulation beam to achieve coverage of the retinal area.

[0017] The dual deformable mirror adjustment module is used to receive aberration data from the wavefront sensor and perform wavefront correction on the incident imaging light and stimulus light through dual mirror linkage. The control module is used to: receive feedback signals from the tracking imaging module and calculate correction values ​​through algorithms; send scanning commands to the dual galvanometer module; send scanning commands to the dual galvanometer adjustment module; send voltage control signals to the dual deformable mirror adjustment module to change the mirror shape; control the retinal functional imaging module to generate light stimulation signals and simultaneously acquire OCT signals.

[0018] Specifically, in this invention: The beacon light source module includes a 780nm narrowband light source 5-1 and matching collimating optical elements; it is used to emit low-coherence beacon light, which is used as a guide to enter the human eye for subsequent wavefront aberration detection and eye movement tracking.

[0019] The tracking imaging module includes a wavefront sensor 5-8, an eye-tracking camera 5-11, and an FSM fast-control mirror 5-12.

[0020] The tracking imaging module receives beacon light reflected from the fundus. This beacon light is used to measure intraocular aberrations via a wavefront sensor and to monitor eye movement in real time via a tracking camera. This monitoring then feeds back to control the FSM (Front-Side Mirror) for closed-loop image stabilization, eliminating the impact of eye tremors on imaging. Specifically: Optical path signal separation principle: The 780nm low-coherence light emitted by the beacon light source 5-1 enters the human eye, and after reflection from the retina, it carries eye movement information and wavefront aberration information back along the same path. The returned beam is relayed by the first 4F system 5-7 and then reaches the third dichroic mirror 5-9. A portion of the beam is split and sent to the wavefront sensor 5-8. This sensor typically employs a Shack-Hartmann architecture to detect the full order of wavefront aberrations in the human eye. The other portion of the beam enters the eye-tracking camera 5-11. This camera is a high-frame-rate, high-sensitivity CMOS camera, responsible for acquiring retinal feature images at a speed far exceeding the video frame rate.

[0021] The tracking imaging module incorporates a closed-loop image stabilization method designed to eliminate microsaccades and drift in non-cooperative targets (such as patients with nystagmus), including the following steps: Step S1: Reference frame selection and ROI locking; When the system starts, it first acquires an image frame as a reference frame at the moment when the eye is relatively still. The algorithm then selects high-contrast retinal blood vessel or optic disc features in the reference frame as regions of interest (ROIs).

[0022] Step S2: Real-time displacement calculation (motion detection algorithm); The tracking camera 5-11 acquires the current frame image in real time. Algorithm selection: The algorithm is either the FFT-based Normalized Cross-Correlation (NCC) algorithm or the sub-pixel phase correlation algorithm (PhaseCorrelation).

[0023] Calculation process: A Fast Fourier Transform (FFT) is performed on the reference frame ROI and the current frame. Then, the cross-power spectrum is calculated. Next, an Inverse Fourier Transform (IFFT) is performed to obtain the correlation peak. The peak positions of the correlation peaks are fitted using a Gaussian surface to calculate the horizontal displacement (Δx) and vertical displacement (Δy) of the current frame relative to the reference frame. This algorithm is insensitive to changes in illumination and has extremely fast computation speed, meeting millisecond-level real-time requirements.

[0024] Step S3: PID closed-loop control; The calculated displacement (Δx, Δy) is input as an error signal into the PID (Proportional-Integral-Derivative) controller. Wherein: Proportional element (P): Quickly responds to current eye position deviation.

[0025] Integrator (I): Eliminates steady-state error and prevents the beam from slowly drifting on the retina.

[0026] Differential component (D): Predicts motion trends and suppresses overshoot, which is especially important for dealing with high-frequency jitter of nystagmus.

[0027] Step S4: FSM driver execution; The control module converts the control output from the PID controller into an analog voltage signal. This signal drives the FSM to rapidly control the piezoelectric ceramic or voice coil motor actuator of the reflector 5-12, causing it to deflect slightly in the X / Y axis directions. The deflection of the FSM changes the optical path angle, ensuring that the point where the incident beam lands on the retina always coincides with the position of the reference frame, thus physically canceling out eye movements and achieving image locking.

[0028] The principle by which the tracking imaging module measures intraocular aberrations using a wavefront sensor is as follows: The wavefront sensor 5-8 is based on a microlens array and a CCD / CMOS detector. The incident distorted wavefront is divided into multiple sub-apertures, and each microlens is focused into a spot on the detector. If the wavefront is planar, the spot is located at the center of an ideal grid; if the wavefront is distorted, the spot will shift.

[0029] Centroiding-based calculation: Utilizing the center of gravity method or a weighted centroid algorithm, the actual position of the light spot at each sub-aperture is accurately calculated. The actual position is compared with the reference position to calculate the local slope of the wavefront at each sub-aperture. Zernike polynomial fitting is used to map the local slope data to Zernike polynomial coefficients (Z_1 to Z_n). Low-order coefficients such as Z_3 (astigmatism) and Z_4 (defocus) are extracted and sent to the Woofer deformable lens 5-29 for significant low-frequency correction. High-order coefficients of Z_6 and above (coma, spherical aberration, etc.) are extracted and sent to the Tweeter deformable lens 5-31 for high-precision high-frequency correction.

[0030] To ensure the system's real-time performance, the control module employs a GPU parallel computing architecture to ensure: eye-tracking closed-loop frequency ≥ 500Hz (i.e., completing one capture-calculation-deflection cycle every 2ms); and wavefront correction closed-loop frequency ≥ 30Hz (to adapt to tear film changes and micro-fluctuations). Both operate in parallel without interference, but share the same beacon light as a reference.

[0031] In this invention, the retinal functional imaging module includes a DMD digital micromirror array 5-17, a red monochromatic light source 5-27, a green monochromatic light source 5-25, a blue monochromatic light source 5-22, and a projection light path.

[0032] The functional retinal imaging module is responsible for generating programmable stimulation patterns (photostimulation signals) of specific wavelengths and shapes. The stimulation light emitted by this module is coupled into the main optical path and projected onto the retina to induce photophysiological responses.

[0033] In this invention, the dual deformable mirror adjustment module includes a Woofer deformable mirror 5-29 and a Tweeter deformable mirror 5-31. It receives aberration data from a wavefront sensor and, through dual-mirror linkage (Woofer corrects low-order large aberrations, Tweeter corrects high-order micro aberrations), performs wavefront correction on the incident imaging light and stimulus light, ensuring the formation of a perfect diffraction-limited spot on the retina. The light beam first passes through the Woofer deformable mirror 5-29, then through the fourth 4F system 5-30, and finally enters the Tweeter deformable mirror 5-31. The fourth 4F system 5-30 ensures that the Woofer mirror, the Tweeter mirror, and the plane of the human eye's pupil are optically precisely conjugated. This ensures that the wavefront aberration acquired by the Tweeter mirror is the wavefront aberration that has been initially corrected by the Woofer mirror and is about to enter the human eye's pupil. Without this conjugation design, the correction effects of the two mirrors would interfere with each other due to diffraction and spatial misalignment, making efficient superposition impossible.

[0034] The dual deformable mirror adjustment module incorporates a wavefront correction method, including the following steps: Step S1: Obtaining full-order wavefront aberrations: The raw wavefront data measured by wavefront sensor 5-8 was reconstructed into a set of Zernike polynomial coefficients. .

[0035] Zernike polynomials are standard mathematical basis functions describing optical aberrations. The lower-order terms correspond to common refractive errors, such as... For defocus / nearsightedness and hyperopia, For astigmatism, higher-order terms correspond to more complex aberrations (such as coma, spherical aberration, etc.).

[0036] Step S2: Aberration task assignment: The control system sets a cut-off order N, for example, N=5 or N=10.

[0037] Low-level task packs: [Increase in order of rank] Zernike coefficient to These were assigned to Woofer deformable mirrors 5-29. These aberrations have large amplitudes but low spatial frequencies, which perfectly match the physical characteristics of Woofer mirrors, which have large strokes and few actuators.

[0038] Advanced Task Pack: Increases the level Zernike coefficient to Assigned to Tweeter morphing lenses 5-31. These aberrations have small amplitudes but high spatial frequencies (high detail), requiring the characteristics of Tweeter lenses, such as "small stroke and dense actuators," for fine engraving.

[0039] Step S3: Voltage calculation based on the influence matrix: The system was pre-calibrated to establish two influence matrices (IM) for the mirrors: and ; The influence matrix describes the deformation of the mirror when a unit voltage is applied to a single actuator (it is also often represented by the Zernike model).

[0040] Control systems solve linear equations (usually by finding the pseudo-inverse of the influence matrix). To calculate the driving voltage: Woofer voltage vector: ; Tweeter voltage vector: ; in, and These are vectors composed of low-order and high-order aberration coefficients, respectively.

[0041] In practice, the system captures the first frame of wavefront aberrations and finds huge low-order defocus (such as -8.0D high myopia) and complex high-order aberrations.

[0042] Woofer coarse adjustment: The control system executes one of the wavefront correction methods described above, sending low-order coefficients representing -8.0D defocus and major astigmatism to the Woofer. The Woofer mirror quickly forms a concave surface, compensating for most of the low-order aberrations. This is equivalent to instantly inserting a perfectly custom-made pair of glasses into the optical path.

[0043] Residual measurement: At this point, after the beam passes through the Woofer, the wavefront is basically flat, but some high-order micro-undulations caused by irregularities in the cornea and lens still remain. The wavefront sensor measures this residual aberration.

[0044] Tweeter Fine-tuning: The control system sends the residual higher-order aberration coefficients to the Tweeter. Driven by high-density actuators, the Tweeter mirror forms a fine surface profile conjugate with the residual aberrations, completely smoothing them out.

[0045] Iterative optimization: The system repeats the above measurement-segmentation-drive closed-loop process at a high frequency (e.g., 30Hz) to counteract human dynamic aberrations such as tear film changes in real time, and always keeps the final wavefront error (Residual Error) below the diffraction limit standard (e.g., RMS < λ / 14).

[0046] To meet the high real-time requirements of the AO closed loop and the throughput requirements of large OCT data volumes, the specific hardware composition of the control module of this invention is preferably a heterogeneous computing architecture of a host computer and an embedded real-time control unit.

[0047] The optical path structure of the system of the present invention is as follows: Light source generation and beam splitting: The light emitted from the broadband OCT light source 1-1 passes through the optical isolator 1-2 to prevent backlight interference and enters the fiber coupler 3. The coupler splits the light into two paths: the reference arm optical path and the sample arm optical path.

[0048] Reference arm: After collimation, the beam enters the glass block 2-2. Its function is to compensate for dispersion, matching the dispersion caused by the vitreous humor of the human eye in the sample arm, and ensuring axial resolution. After passing through the first focusing lens 2-3, it is projected onto the motorized mirror 2-4. The motorized mirror can move back and forth to adjust the optical path of the reference arm, matching the differences in optical path caused by different patients' axial lengths. The reflected light returns to the fiber coupler 3 along the original path.

[0049] The backscattered light returned by the sample arm (human eye) interferes with the light returned by the reference arm at coupler 3. The interference signal is transmitted to spectrometer 4, and after being dispersed by a grating, it is collected by a linear array camera. The depth structure information is reconstructed through Fourier transform.

[0050] Beacon emission: The beacon light source 5-1 forms a parallel beam through the optical isolator 5-2, the reflector 5-3, and the second collimator 5-4. This beam is reflected and coupled into the main optical path through the first dichroic mirror 5-5, serving as a guide beam for the human eye.

[0051] Signal Separation and Detection: The beacon light reflected from the human retina carries wavefront distortion and eye movement information. The returning beam is split by the second dichroic mirror 5-6 and the third dichroic mirror 5-9, entering two branches: the wavefront detection branch and the eye-tracking branch. Wavefront detection branch: Part of the beam enters the wavefront sensor 5-8 after being relayed by the first 4F system 5-7, and is used to measure the wavefront aberration of the whole eye in real time.

[0052] Eye-tracking branch: Another portion of the beam is imaged via the 4F system 5-10 to the eye-tracking camera 5-11. The camera captures retinal feature displacements at a high frame rate to calculate eye movement.

[0053] FSM image stabilization: The FSM quickly controls the reflector 5-12 to be placed at a critical node in the optical path. The feedback signal from the eye-tracking camera 5-11 drives the FSM to perform micro-deflection, compensating for lateral eye movement and ensuring that the light beam entering the system afterward remains relatively stationary.

[0054] XY Scan: After being relayed by relay lenses 5-13, the beam reaches the XY scanning galvanometer group 5-14. The galvanometer is responsible for performing two-dimensional raster scanning or vector scanning of the beam to cover the retinal imaging area.

[0055] Multicolor light source synthesis: Blue monochromatic light source 5-22, green monochromatic light source 5-25, and red monochromatic light source 5-27 pass through the corresponding first optical shutter 5-24, second optical shutter 5-26, and third optical shutter 5-21, respectively; after being combined by the second dichroic mirror 5-23 and the fifth dichroic mirror 5-20, they form an illumination light with an adjustable spectrum.

[0056] The combined light enters the homogenizing rod 5-19 to eliminate speckle and homogenize, and is then expanded by the second 4F system 5-18 to illuminate the surface of the DMD digital micromirror array device 5-17. The DMD modulates the reflected light by flipping the micromirrors to generate specific stimulation patterns such as checkerboard patterns and rings.

[0057] Optical path coupling: The stimulation light is relayed through the 4F system 5-16 and coupled into the main optical path through the fourth dichroic mirror 5-15, and projected onto the retina coaxially with the OCT imaging light and the beacon light.

[0058] The double deformable mirror wavefront correction module is located near the human eye, specifically on the side closest to sample 5-36. It is used to correct aberrations in all beams entering and exiting the eye, including OCT light, beacon light, and stimulus light. Within the double deformable mirror wavefront correction module, the beam sequentially passes through the third 4F system 5-28, the Woofer deformable mirror 5-29, the fourth 4F system 5-30, and the Tweeter deformable mirror 5-31. The corrected beam then passes through the reflecting mirror 5-32, the second focusing lens 5-33, the fifth 4F system 5-34, and the safety shutter 5-35, finally focusing onto sample 5-36, i.e., the human eye's retina.

[0059] The overall workflow of this invention is as follows: Step 1: System Initialization and Focusing 1. Turn on the beacon light source 5-1; the beam passes through the FSM fast control mirror 5-12, the XY scanning galvanometer group 5-14, the woofer deformable mirror 5-29, the tweeter deformable mirror 5-31, and enters the human eye sample 5-36.

[0060] 2. Wavefront sensor 5-8 detects the main defocus amount. The control module drives the woofer deformable lens 5-29 to undergo significant deformation, achieving autofocus and replacing traditional insert-type refraction. Step 2: Initiate hardware closed-loop dual lockout: 1. Image Stabilization Closed-Loop: The eye-tracking camera 5-11 is activated to lock onto retinal features. The control module calculates the displacement and drives the FSM to quickly control the reflector 5-12 in real time, canceling nystagmus within milliseconds.

[0061] 2. AO Closed Loop: Wavefront sensor 5-8 is activated to measure residual higher-order aberrations in real time. The control module uses an algorithm to allocate the aberrations to the tweeter deformable mirror 5-31 for fine compensation, enabling the retinal image to achieve diffraction-limited resolution.

[0062] Step 3: Structural Imaging Pre-stimulus: 1. Turn on the OCT light source 1-1. Control the XY scanning galvanometer group 5-14 to perform raster scanning.

[0063] 2. The spectrometer 4 collects interference signals and obtains a high-resolution image of the retinal reference structure, showing individual photoreceptor cells.

[0064] Step 4: Functional Stimulus & Response 1. Control the DMD digital micromirror array device 5-17 to project a stimulation pattern of a specific wavelength and shape onto a specific area of ​​the retina.

[0065] 2. Within a specific time window after the stimulation light is projected, such as 0-10ms, control the XY scanning galvanometer group 5-14 to perform local rapid repeated scanning of the stimulated area.

[0066] 3. The OCT system records the physiological response of cells to light stimulation by detecting the optical path change (ORG) signal of the outer segment OS of the photoreceptor.

[0067] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, alterations, alterations, or substitutions made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An OCT imaging system based on a dual deformable mirror and a digital micromirror array, characterized in that, include: The beacon light source module is used to emit beacon light for subsequent wavefront aberration detection and eye movement tracking. The tracking imaging module is used to receive beacon light reflected from the fundus; one path of the beacon light is used to measure intraocular aberrations through a wavefront sensor; the other path of the beacon light is used to monitor eye movement in real time through a tracking camera and perform closed-loop image stabilization to eliminate the influence of eye tremors on imaging. The functional retinal imaging module includes a DMD digital micromirror array, which generates light stimulation signals and projects them onto the retina to induce photophysiological responses. Dual galvanometer adjustment module: including XY scanning galvanometer group and FSM fast control mirror; wherein, the XY scanning galvanometer group is used to perform two-dimensional raster scanning of OCT imaging beam and stimulation beam to cover the retinal imaging area; the FSM fast control mirror performs real-time motion compensation based on eye tracking signal; The dual deformable mirror adjustment module is used to receive aberration data from the wavefront sensor and perform wavefront correction on the incident imaging light and stimulus light through dual-mirror linkage. The control module is used to: receive feedback signals from the tracking imaging module and calculate correction values ​​through algorithms; send scanning commands to the dual galvanometer adjustment module; send voltage control signals to the dual deformable mirror adjustment module to change the mirror shape; control the retinal functional imaging module to generate light stimulation signals and simultaneously acquire OCT signals.

2. The OCT imaging system based on a dual deformable mirror and a digital micromirror array according to claim 1, characterized in that, The beacon light source module includes a narrowband light source and matching collimating optical elements.

3. The OCT imaging system based on a dual deformable mirror and a digital micromirror array according to claim 1, characterized in that, The tracking imaging module includes a wavefront sensor and an eye-tracking camera.

4. The OCT imaging system based on a dual deformable mirror and a digital micromirror array according to claim 1, characterized in that, The retinal functional imaging module includes a red monochromatic light source, a green monochromatic light source, a blue monochromatic light source, and a projection light path.

5. The OCT imaging system based on a dual deformable mirror and a digital micromirror array according to claim 1, characterized in that, The dual deformable mirror adjustment module includes a Woofer deformable mirror and a Tweeter deformable mirror.

6. A closed-loop image stabilization method, characterized in that, The OCT imaging system based on a dual deformable mirror and a digital micromirror array as described in claim 1 or 3 includes the following steps: Step S1: Reference Frame Selection and ROI Locking: When the system starts up, it first acquires an image frame as a reference frame at the moment when the eye is relatively still; and selects high-contrast retinal blood vessels or optic disc features as regions of interest in the reference frame. Step S2: Real-time displacement calculation: The tracking camera acquires the current frame image in real time; a normalized cross-correlation algorithm or a subpixel-level phase correlation algorithm based on FFT is used; a fast Fourier transform is performed on the region of interest of the reference frame and the current frame; then the cross power spectrum is calculated; then an inverse Fourier transform is performed to obtain the correlation peak; the peak position of the correlation peak is fitted by a Gaussian surface to calculate the horizontal and vertical displacement of the current frame relative to the reference frame. Step S3: PID closed-loop control: The calculated horizontal and vertical displacements are input as error signals to the PID controller; Step S4: FSM driver execution: The control module converts the control quantity output by the PID controller into an analog voltage signal; drives the FSM to quickly control the piezoelectric ceramic or voice coil motor actuator of the reflector, causing it to deflect slightly in the horizontal and vertical directions; the deflection of the FSM changes the optical path angle, so that the point where the incident beam lands on the retina always coincides with the position of the reference frame, thereby physically canceling eye movement and achieving image locking.

7. A wavefront correction method, characterized in that, The OCT imaging system based on a dual deformable mirror and a digital micromirror array as described in claim 1 or 3 includes the following steps: Step S1: Obtaining full-order wavefront aberrations: The raw wavefront data measured by the wavefront sensor is reconstructed into a set of Zernike polynomial coefficients: ; Step S2: Aberration task assignment: Set the partitioning order N=5 or N=10; then set the order... Zernike coefficient to Assign to the Woofer deformable mirror; change the order Zernike coefficient to Assigned to the Tweeter morphing mirror; Step S3: Voltage calculation based on the influence matrix: Establish the influence matrices for the Woofer and Tweeter deformable mirrors: and ; Obtain the voltage vector of the Woofer deformable mirror: ; Obtain the voltage vector of the Tweeter deformable mirror: ; in, and These are vectors composed of low-order and high-order aberration coefficients, respectively. and This is the pseudo-inverse of the corresponding influence matrix.

Images