Optical coherence tomography system with adjustable diaphragm and control method thereof

Abstract

The embodiment of the invention discloses a diaphragm-adjustable optical coherence tomography system and a control method thereof.In the system, an adjustable diaphragm is used for changing the aperture of the diaphragm so as to adjust original laser emitted by a light source, and adjusted laser is obtained; the interferometer is used for splitting the adjusted laser into reference light and sample light; the interferometer is also used for receiving reflected light of the sample arm and the reference arm to form an interference signal; the detector is used for performing image reconstruction according to the interference signal to obtain a real-time detection image; the image monitoring equipment is used for monitoring the real-time detection image and analyzing the imaging quality of the real-time detection image; and the control system is used for feeding back and adjusting the diaphragm aperture of the adjustable diaphragm at least according to the imaging quality of the real-time detection image, so that the real-time detection image reaches a preset imaging quality standard. According to the method, the light beam quality is optimized in real time in a mode of intelligently regulating and controlling the variable diaphragm, and the signal-to-noise ratio and the resolution ratio of OCT imaging are remarkably improved in combination with a self-adaptive optical compensation technology.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the field of optical precision measurement, in particular to an optical coherence tomography system with adjustable diaphragm and a control method thereof. BACKGROUND

[0002] Traditional optical coherence tomography (OCT) is limited in lateral resolution by the bandwidth of the light source, optical system aberration and stray light interference, especially in deep tissue imaging, scattered light reduces image contrast.

[0003] The current mainstream measurement method has the following technical defects: the current mainstream OCT (optical coherence tomography) lateral resolution optimization method mainly relies on the following technical means, but there are still obvious limitations, and the specific defects are as follows: high numerical aperture (NA) objective lens improves resolution, the defect is that although the high NA objective lens can improve the lateral resolution, the depth of focus is extremely short, which leads to a sharp decline in resolution when imaging deep, limiting its application in thick tissue detection. It is impossible to ensure high resolution and sufficient imaging depth at the same time in a single scan, and part of the performance needs to be sacrificed or relies on complex dynamic focusing technology. Adaptive optics (AO-OCT) corrects aberration, the defect is that it relies on complex and expensive deformable mirrors (DM) or spatial light modulators (SLM), the adjustment process is time-consuming, and the system stability requirement is extremely high. It is suitable for laboratory research, but it is difficult to commercialize and promote, and it has poor adaptability to dynamic changes of samples. The defect of optical confocal enhancement (confocal OCT) is to use confocal pinhole filtering to suppress stray light, but the fixed size of the pinhole cannot adapt to different sample scattering characteristics, resulting in a significant reduction in signal-to-noise ratio (SNR) and resolution in strongly scattering samples (such as skin, tumor tissue). Only suitable for low scattering samples, limited clinical applicability. Computational super-resolution methods (such as deep learning deconvolution, sparse reconstruction), the defect is that it relies on a large amount of training data, and the reconstruction algorithm may introduce artifacts, which cannot guarantee physical accuracy. Difficult to process in real time, high computational cost, and no direct optimization effect on hardware. SUMMARY

[0004] The present application provides an optical coherence tomography system with adjustable diaphragm and a control method thereof, which optimizes the beam quality in real time through intelligent control of the variable diaphragm, and combines adaptive optical compensation technology to significantly improve the signal-to-noise ratio and resolution of OCT imaging. It can be widely used in key fields such as medical diagnosis and treatment, life science research, industrial non-destructive testing, and has important scientific value and application prospect.

[0005] In a first aspect, the embodiment of the present application provides an optical coherence tomography system with adjustable diaphragm, comprising:

[0006] a light source for emitting original laser light;

[0007] an adjustable aperture for changing an aperture of the aperture to adjust the original laser to obtain an adjusted laser;

[0008] an interferometer for splitting the adjusted laser into a reference light and a sample light;

[0009] a reference arm for transmitting the reference light and feeding back a reflected light of the reference light to the interferometer;

[0010] a sample arm for transmitting the sample light to a sample to be measured to form a sample reflected light and feeding back to the interferometer; wherein the interferometer is further configured to receive the sample reflected light to interfere with the reflected light of the reference light to form an interference signal;

[0011] a detector configured to reconstruct an image according to the interference signal to obtain a real-time detection image;

[0012] an image monitoring device configured to monitor the real-time detection image and analyze an imaging quality of the real-time detection image;

[0013] a control system configured to feed back an adjustment of the aperture of the adjustable aperture according to at least the imaging quality of the real-time detection image to make the real-time detection image reach a preset imaging quality standard.

[0014] Optionally, the imaging quality of the real-time detection image includes an imaging resolution and a signal-to-noise ratio.

[0015] The control system is further configured to input the imaging resolution and the signal-to-noise ratio of the real-time detection image into a machine learning algorithm model which is pre-trained to obtain a target aperture of the adjustable aperture which satisfies a target imaging quality standard, and control the adjustable aperture to adjust to the target aperture.

[0016] Optionally, further comprising a wavefront sensor located on an optical path between the adjustable aperture and the sample to be measured.

[0017] The wavefront sensor is configured to measure a wavefront aberration of the sample light in real time.

[0018] The control system is further configured to adjust the aperture of the adjustable aperture in real time according to the wavefront aberration of the sample light to make the wavefront aberration of the sample light reach a preset wavefront aberration standard.

[0019] Optionally, the wavefront aberration of the sample light includes a wavefront distortion.

[0020] The control system is further configured to adjust the aperture of the adjustable aperture in real time according to an adaptive optics algorithm to make the wavefront distortion of the sample light reach a preset wavefront distortion standard.

[0021] Optionally, the adjustable diaphragm comprises a driving motor, a driving ring and a plurality of rotating blades;

[0022] The plurality of rotating blades are arranged in sequence around the optical axis in a circumferential direction, and edges of the rotating blades are overlapped to form an adjustable diaphragm aperture; an axis is arranged on the rotating blade, and a movable shaft is arranged on the rotating blade and connected with the driving ring;

[0023] The driving motor is used to drive the driving ring to rotate, so as to drive each rotating blade to rotate around the axis through the movable shaft, change the overlapping degree of the edges of the adjacent rotating blades, and obtain different diaphragm apertures.

[0024] In a second aspect, the embodiment of the present application further provides a control method of an optical coherence tomography system with an adjustable diaphragm, which is applied to the optical coherence tomography system with the adjustable diaphragm in any one of the first aspect;

[0025] The control method comprises:

[0026] controlling the light source to emit original laser; wherein the adjustable diaphragm adjusts the original laser by changing a diaphragm aperture to obtain adjusted laser; the interferometer splits the adjusted laser into reference light and sample light; the reference arm transmits the reference light and feeds back reflected light of the reference light to the interferometer;

[0027] controlling the scanning unit to control the sample light to scan a to-be-measured sample to form sample reflected light and feed back to the interferometer; wherein the interferometer receives the sample reflected light to generate interference with the reflected light of the reference light to form an interference signal;

[0028] controlling the detector to perform image reconstruction according to the interference signal to obtain a real-time detection image;

[0029] controlling the image monitoring device to monitor the real-time detection image and analyze the imaging quality of the real-time detection image;

[0030] at least according to the imaging quality of the real-time detection image, feedback adjusts the diaphragm aperture of the adjustable diaphragm to make the real-time detection image reach a preset imaging quality standard.

[0031] Optionally, the imaging quality of the real-time detection image comprises imaging resolution and signal-to-noise ratio;

[0032] at least according to the imaging quality of the real-time detection image, feedback adjusts the diaphragm aperture of the adjustable diaphragm to make the real-time detection image reach a preset imaging quality standard, comprising:

[0033] In the model application stage, the imaging resolution and signal-to-noise ratio of the real-time detection image are input into the machine learning algorithm model which has been trained in advance to obtain a target aperture stop aperture that meets the target imaging quality standard, and the target aperture stop aperture is controlled to be adjusted by the adjustable aperture stop.

[0034] Optionally, the control method further comprises:

[0035] In the model training stage, a machine learning algorithm model is established.

[0036] In the model training stage, a machine learning algorithm model is established.

[0037] In the model training stage, a machine learning algorithm model is established.

[0038] In the model training stage, a machine learning algorithm model is established.

[0039] In the model training stage, a machine learning algorithm model is established.

[0040] Optionally, the optical coherence tomography system further comprises a wavefront sensor located on an optical path between the adjustable aperture stop and the sample to be measured.

[0041] The control method further comprises:

[0042] The wavefront sensor is controlled to measure the wavefront aberration of the sample light in real time.

[0043] According to the wavefront aberration of the sample light, the aperture stop aperture of the adjustable aperture stop is adjusted in real time to make the wavefront aberration of the sample light reach a preset wavefront aberration standard.

[0044] Optionally, the wavefront aberration of the sample light comprises wavefront distortion.

[0045] According to the wavefront aberration of the sample light, the aperture stop aperture of the adjustable aperture stop is adjusted in real time to make the wavefront aberration of the sample light reach a preset wavefront aberration standard.

[0046] According to the wavefront aberration of the sample light, the aperture stop aperture of the adjustable aperture stop is adjusted in real time to make the wavefront aberration of the sample light reach a preset wavefront aberration standard.

[0047] In summary, the optical aperture adjustable optical coherence tomography system and the control method thereof provided by the embodiment of the present application realize significant improvement in lateral resolution and signal-to-noise ratio through real-time optimization of the beam quality in the OCT imaging process. Compared with the traditional OCT system, the present application has the following advantages:

[0048] 1. Real-time optimization of beam quality: The embodiments of the present application use intelligent control of variable diaphragm and adaptive optical compensation technology, which can adjust the focusing and optical distortion of the light beam in the OCT imaging process in real time, significantly improving the imaging quality. Traditional systems lack real-time adjustment capability, often leading to unstable imaging quality, affecting the diagnostic accuracy.

[0049] 2. Improve imaging resolution and signal-to-noise ratio: By precisely adjusting the shape and aperture of the diaphragm, the system effectively reduces the spot geometric radius and eliminates the residual spherical aberration of the beam periphery, making the imaging clearer and the lateral resolution significantly improved. Compared with traditional OCT systems, the imaging signal-to-noise ratio is also significantly improved, which can more clearly identify the fine structure.

[0050] 3. Optimize high-frequency information transmission: The addition of the diaphragm optimizes the optical transfer function (OTF), although the OTF modulus decreases slightly, but the high-frequency part is effectively improved, thereby improving the system's high-frequency information transmission capability, ensuring higher quality of detail imaging.

[0051] 4. Improve imaging speed and accuracy: The embodiments of the present application use adaptive algorithms and intelligent control systems to make the diaphragm adjustment and imaging process more efficient and accurate. Compared with traditional solutions, the system can respond more quickly to environmental changes, realize real-time optimization, improve imaging speed and ensure imaging accuracy.

[0052] 5. Higher adaptability and robustness: The intelligent control system of the embodiments of the present application can adjust the diaphragm configuration based on real-time feedback, so that it can automatically optimize in various different imaging environments, with stronger adaptability. In addition, the precise control of the diaphragm design also enhances the robustness of the system to external environmental changes, avoiding the unstable factors in traditional systems.

[0053] 6. Through the revolutionary peak distance analysis method, the embodiments of the present application comprehensively surpass traditional solutions in speed, cost, robustness and adaptability, not only significantly improving the OCT imaging quality, but also reducing the system complexity, with high industrialization value. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a structural schematic diagram of an optical coherence tomography system with adjustable diaphragm provided by the embodiments of the present application;

[0055] Figure 2 and Figure 3 are spot column graphs detected by the spectrometer under two field of view ranges when the diaphragm is not set to limit the light beam;

[0056] Figure 4 is a circle-in energy graph detected by the spectrometer when the diaphragm is not set to limit the light beam;

[0057] Figure 5 is an OTF curve chart detected by the spectrometer when the light beam is not limited by the diaphragm;

[0058] Figure 6 and Figure 7 are spot column charts detected by the spectrometer under two field of view ranges when the light beam is limited by the diaphragm;

[0059] Figure 8 is a circle-in energy chart detected by the spectrometer when the light beam is limited by the diaphragm;

[0060] Figure 9 is an OTF curve chart detected by the spectrometer when the light beam is limited by the diaphragm;

[0061] Figure 10 is a structure schematic diagram of a diaphragm provided by an embodiment of the present application;

[0062] Figure 11 is a control method flow chart of an optical coherence tomography system with a diaphragm provided by an embodiment of the present application;

[0063] Figure 12 is a control method flow chart of another optical coherence tomography system with a diaphragm provided by an embodiment of the present application. DETAILED DESCRIPTION

[0064] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0065] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. It should be noted that the orientation words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present application are described in the angle shown in the drawings, and should not be understood as limiting the embodiments of the present application. In addition, it should be understood in the context that when referring to an element being formed "on" or "under" another element, it can be directly formed "on" or "under" another element, or indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second" and the like are only for the purpose of description, and do not represent any order, quantity or importance, but are only used to distinguish different components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0066] The term "include" and variations thereof used in the present disclosure mean a non-exclusive inclusion, i.e. "including, but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment".

[0067] It should be noted that the "first", "second", and the like concepts mentioned in the present application are only used to distinguish the corresponding content, and are not used to limit the order or interdependence.

[0068] It should be noted that the modification of "one" or "multiple" mentioned in the present application is illustrative but not restrictive, and those skilled in the art should understand that unless the context clearly indicates otherwise, it should be understood as "one or more".

[0069] As described in the background section, the current optical coherence tomography (OCT) system faces the following key problems in achieving high-resolution imaging, which are caused by the inherent defects of the prior art, limiting the wide application of OCT in clinical diagnosis and industrial detection:

[0070] 1. The contradiction between high resolution and imaging depth. The prior art (such as the high-NA objective lens scheme) tries to improve the lateral resolution by increasing the numerical aperture, but it causes the focal depth to be sharply shortened (such as the focal depth is only about 100 μm when NA=0.3). In vivo detection (such as skin disease diagnosis), both the stratum corneum (resolution sensitive) and the dermis layer (depth>0.5mm) need to be observed, and the traditional system can only be achieved by multiple scanning splicing, which not only reduces the efficiency (the scanning time is increased by 3-5 times), but also affects the diagnosis accuracy due to motion artifacts.

[0071] 2. Insufficient adaptability of dynamic samples. For real-time imaging of biological tissues (such as intravascular OCT), both of the existing two types of solutions have serious defects. Adaptive optical OCT: the wavefront correction delay (>20ms) cannot track the blood vessel wall pulsation (period about 50ms); confocal OCT: the fixed pinhole will cause the effective signal loss rate to be >40% in the blood flow field due to the strong scattering characteristics of red blood cells.

[0072] 3. Technical bottleneck of stray light suppression. In deep tissue imaging, scattered light noise will cover the real signal. The existing technology has the following shortcomings. Hardware filtering (such as pinhole): will simultaneously attenuate the effective signal (the actual signal intensity loss at 1mm depth is up to 60%); software algorithm (such as deconvolution): cannot distinguish between real signal and scattered noise, and is invalid when the signal-to-noise ratio is <10dB.

[0073] 4. Cost and complexity constraints. The correction module of adaptive optical OCT costs more than 200,000 yuan, and requires professional optical engineers for maintenance; the calculation of the super-resolution scheme relies on GPU clusters (the operation cost of a single device is >50,000 yuan), which is difficult to popularize in primary hospitals.

[0074] To solve the above problems, the embodiment of the present application provides an optical coherence tomography system with adjustable diaphragm, Figure 1 is a structural schematic diagram of an optical coherence tomography system with adjustable diaphragm provided by the embodiment of the present application. The OCT system comprises: a light source 10 for emitting original laser; an adjustable diaphragm 20 for changing a diaphragm aperture to adjust the original laser to obtain adjusted laser; an interferometer 30 for splitting the adjusted laser into reference light and sample light; a reference arm 41 for transmitting the reference light and feeding back reflected light of the reference light to the interferometer 30; a sample arm 42 for transmitting the sample light to a sample to be measured to form sample reflected light and feeding back to the interferometer 30; wherein the interferometer 30 is further configured to receive the sample reflected light to generate interference with the reflected light of the reference light to form an interference signal; a detector (not shown in the figure) configured to reconstruct an image according to the interference signal to obtain a real-time detection image; an image monitoring device 50 configured to monitor the real-time detection image and analyze the imaging quality of the real-time detection image; and a control system (not shown in the figure) configured to feed back the diaphragm aperture of the adjustable diaphragm 20 according to at least the imaging quality of the real-time detection image to make the real-time detection image reach a preset imaging quality standard.

[0075] In the embodiment of the present application, the adjustable diaphragm 20 is added in the OCT system, and the adjustable diaphragm 20 is specifically arranged between the light source 10 and the interferometer 30 of the system. The adjustable diaphragm 20 can adjust the intensity of the incident light and the quality of the light beam. It can not only adjust the light intensity incident to the sample to be measured by adjusting the diaphragm aperture to avoid damage to the sample caused by the over-intense light beam, but also adjust the depth resolution of the imaging based on the aperture size of the adjustable diaphragm 20 to affect the focal point size of the light beam. Therefore, the embodiment of the present application uses the adjustable diaphragm 20 to change the diaphragm aperture, the purpose of which is to optimize the energy distribution of the original laser, so as to adjust the focusing of the light beam and the optical distortion, thereby significantly improving the imaging quality and improving the lateral resolution of the OCT system. Specifically, the theoretical analysis of using the adjustable diaphragm 20 to improve the lateral resolution of the OCT is as follows:

[0076] Those skilled in the art can understand that the light emitted by the light source 10 can be approximately considered as Gaussian light, and according to the Gaussian radial light intensity distribution formula: Generally, r at the position of is defined as the spot radius, and the amplitude at the radius r is Where A_0 is the face center amplitude, r is the distance from the face center, and ω is the Gaussian beam radius. Therefore, the diffraction spot on the image plane can be regarded as two parts, the energy dense spot with a radius of r and the peripheral low-energy annulus. In theory, by adding a diaphragm in the optical path, part of the edge light can be blocked and the high-energy spot can be retained, at the cost of slightly reducing the light intensity to achieve the effect of reducing the spot and enhancing the contrast. However, considering that reducing the clear aperture may enhance the diffraction effect of the light beam, the actual effect needs to be verified by experiments.

[0077] Figure 2 and Figure 3 are the spot column graphs of two field of view ranges detected by the spectrometer when the light beam is not limited by the diaphragm, Figure 4 is the enclosed energy graph detected by the spectrometer when the light beam is not limited by the diaphragm, Figure 5 is the OTF curve graph detected by the spectrometer when the light beam is not limited by the diaphragm, Figure 6 and Figure 7 are the spot column graphs of two field of view ranges detected by the spectrometer when the light beam is limited by the diaphragm, Figure 8 is the enclosed energy graph detected by the spectrometer when the light beam is limited by the diaphragm, Figure 9 is the OTF curve graph detected by the spectrometer when the light beam is limited by the diaphragm, wherein Figures 2-5 , through ZEMAX simulation, the beam aperture from the grating is about 15mm when the light beam is not limited by the diaphragm. Referring to Figures 6-9 , when the diaphragm limits the light beam, the clear aperture is set to 12mm.

[0078] As can be seen, without the diaphragm, the light beam enters the OCT system and propagates, and due to the divergence of the light beam and the optical distortion in the system, the geometric radius of the spot is large. This large spot means that the focus of the imaging system is more blurred, the energy distribution of the light beam is more dispersed, and the resolution of the image is reduced. After adding the diaphragm, the passing path of the light beam is limited by the introduction of the diaphragm, and the geometric radius of the spot is significantly reduced. The diaphragm controls the propagation path of the light beam, so that the spot is more concentrated and the divergence of the light beam is reduced. This light beam convergence effect significantly improves the clarity and resolution of the imaging.

[0079] As can be seen, without the aperture, the light energy at the periphery of the spot is more dispersed due to the divergence of the beam, resulting in lower encircled energy at the same radius. The details of the image are difficult to clearly present, and the imaging quality is reduced. After adding the aperture, by controlling the passing path of the beam, the aperture effectively concentrates the light energy in a smaller area, thereby increasing the encircled energy at the same radius. Although the total energy of the beam may be reduced after adding the aperture, due to the bunching effect of the beam, the distribution of the encircled energy is more concentrated, and the quality of the image is improved. Therefore, it can be known that after adding the aperture, the encircled energy at the same radius is reduced, but the energy distribution is more concentrated, thereby improving the imaging quality.

[0080] As can be seen, without the aperture, the optical transfer function (OTF) of the OCT system is affected by the optical distortion of the system, especially in the high frequency part, the OTF modulus is low. This means that without the aperture, the high frequency information of the image (i.e. the detail part of the image) is greatly affected, resulting in poor image resolution. After introducing the aperture, the passing path of the beam is limited, reducing some distortions in the system, especially the residual spherical aberration at the periphery of the beam is effectively eliminated. This makes the OTF modulus slightly decrease, but due to the more concentrated and regular beam, the high frequency part of the system is improved, thereby improving the lateral resolution. Therefore, although the OTF modulus slightly decreases after adding the aperture, due to the elimination of spherical aberration and the improvement of the spot shape, the high frequency transfer capability of the system is improved.

[0081] As can be seen, after adding the aperture, the spot shape is more regular, and the peripheral residual spherical aberration is also eliminated. Without the aperture, the divergence of the beam and the distortion of the optical system result in low lateral resolution of the system. The geometric radius of the spot is large, resulting in focal blur, thereby affecting the imaging quality of the OCT. The resolution of the system is limited, especially in the peripheral region of the image. After adding the aperture, the spot geometric radius is reduced, the divergence of the beam is suppressed, and the focus of the imaging system is more clear. The shape of the spot becomes more regular, removing the peripheral residual spherical aberration, thereby improving the lateral resolution of the system. Through the adjustment of the aperture, the edge part of the image can also be imaged more clearly, and the resolution is improved. Therefore, after adding the aperture, the lateral resolution of the OCT system is significantly improved, especially in the edge part of the image, the imaging is more clear and delicate.

[0082] In summary, through Zemax simulation analysis, after adding the diaphragm, the OCT system is optimized in many aspects. First, the light spot is more concentrated, the geometric radius is reduced, and the beam divergence is reduced. Second, the energy distribution is more concentrated, although the circle-in energy at the same radius is reduced, but the energy distribution is more conducive to improving the image quality. The OTF modulus slightly decreases, but the high-frequency information is preserved, and the details of the image are more abundant. The lateral resolution is significantly improved, and the image is clearer, especially in the edge part of the imaging. In general, the addition of the diaphragm improves the imaging quality of the OCT system, especially in terms of resolution and image clarity, which is of great significance for high-resolution OCT imaging and tissue analysis.

[0083] In addition, those skilled in the art can know that the basic principle of the OCT system is that the interference of the reflected light of the sample arm 42 and the reference arm 41 is formed, and the interference information is detected by the detector, so that the surface or internal of the sample to be measured in the sample arm 42 can be imaged, and a real-time detection image can be obtained. Among them, the light source 10 can use a broadband light source 10 (such as a hyperspectral light source 10 or a swept laser light source 10) to provide high-resolution imaging. The selection of the light source 10 will affect the depth resolution and imaging speed of the system. The interferometer 30 can adopt a Michelson interferometer 30, wherein the interferometer 30 generates imaging information through interference signals. A scanning unit can be arranged in the sample arm 42, and the scanning unit is used for point-by-point scanning on the sample to be measured and capturing the reflected signal. The optional scanning methods include line scanning (A-scan) and image scanning (B-scan). The detector is used for receiving the interference signal reflected from the sample to be measured and converting it into an electronic signal for image reconstruction. The detector of the present embodiment can be a photodiode array. The image monitoring device is a very important part of the OCT system, which is responsible for real-time monitoring of the imaging quality of the system. The image monitoring device is generally closely combined with the detector or the imaging scanning unit, and is used for real-time display of the OCT image. An image processing system can also be integrated to evaluate the image quality in real time. The monitoring device needs to have high-resolution display capability and be able to connect with the control system for feedback adjustment.

[0084] It can be understood that, based on the real-time detection image obtained by the image monitoring device 50, the image analysis software possessed by the image monitoring device 50 itself is used to obtain image quality data, and then based on the aperture adjustment effect of the diaphragm, the energy distribution of the light beam is optimized to change the image quality, thereby significantly improving the lateral resolution and clarity.

[0085] Figure 10 is a structure diagram of a tunable diaphragm provided by the embodiment of the present application, referring to Figure 10In the above embodiment, the adjustable diaphragm 20 can include a driving motor 21, a driving ring 22, and a plurality of rotating blades 23; the plurality of rotating blades 23 are arranged in sequence around the optical axis in a circular manner, and the edges of the rotating blades 23 are overlapped to form an aperture of the adjustable diaphragm 20; the rotating blades 23 are provided with a fixed shaft and a movable shaft, and the movable shaft is rotationally connected with the driving ring 22; the driving motor 21 is used to drive the driving ring 22 to rotate, so as to drive each rotating blade 23 to rotate around the respective fixed shaft through the movable shaft, change the overlapping degree of the edges of the adjacent rotating blades 23, and obtain different diaphragm apertures.

[0086] In the adjustable diaphragm 20, the rotating blades 23 (or blade array) change the size of the aperture by rotating or pushing. By driving the rotating blades 23 to rotate, the arrangement angle of the rotating blades 23 changes, thereby expanding or reducing the aperture of the diaphragm. The size of the aperture directly affects the intensity of the light beam entering the system and the size of the focus of the light beam. Adjustment usually occurs when optimization according to image quality is needed, such as when image resolution decreases or distortion occurs. At this time, the spiral blade adjusts the diaphragm aperture according to the feedback signal to ensure that the imaging quality is maximized. In addition, the driving motor 21 in the embodiment can be a stepper motor or a servo motor. The stepper motor can be used for precise and discrete control, and can provide precise angle adjustment by rotating in step units, to accurately control the angle of the rotating blades 23. The control accuracy of the stepper motor is high, but the motion smoothness is not as good as that of the servo motor. The stepper motor is more suitable for occasions that require fine but non-continuous adjustment, such as precise control of the opening and closing of the aperture. The servo motor can realize continuous adjustment through feedback control, and can accurately control the size change of the diaphragm aperture and the motion is smooth. The servo motor is suitable for more complex adjustment tasks, such as when fast response and fine adjustment are required. The servo motor provides a smooth adjustment process, and is usually used in situations that require high precision and fast response, such as in real-time image monitoring systems, where the diaphragm is quickly adjusted according to real-time feedback.

[0087] Based on the above adjustable diaphragm OCT system, the embodiment of the present application further provides a control method of the adjustable diaphragm OCT system, Figure 11 is a control method flowchart of the adjustable diaphragm OCT system provided by the embodiment of the present application, referring to Figure 11 The control method can be executed by the control system in the above OCT system, and specifically can include:

[0088] S110, control the light source to emit original laser; wherein, the adjustable diaphragm adjusts the original laser by changing the diaphragm aperture to obtain adjusted laser; the interferometer splits the adjusted laser into reference light and sample light; the reference arm transmits the reference light and feeds back the reflected light of the reference light to the interferometer; the sample arm transmits the sample light to the sample to be measured to form sample reflected light and feed back to the interferometer; the interferometer receives the sample reflected light to interfere with the reflected light of the reference light to form an interference signal.

[0089] S120, control the detector to perform image reconstruction according to the interference signal to obtain a real-time detection image.

[0090] S130, control the image monitoring device to monitor the real-time detection image and analyze the imaging quality of the real-time detection image.

[0091] S140, at least according to the imaging quality of the real-time detection image, feedback adjusts the diaphragm aperture of the adjustable diaphragm to make the real-time detection image reach the preset imaging quality standard.

[0092] On the basis of the above embodiment, further optionally, the imaging quality of the real-time detection image includes imaging resolution and signal-to-noise ratio. The control system is also used to input the imaging resolution and signal-to-noise ratio of the real-time detection image into the machine learning algorithm model which is pre-trained to obtain a target diaphragm aperture which meets the target imaging quality standard, and control the adjustable diaphragm 20 to adjust to the target diaphragm aperture.

[0093] The embodiment is essentially to analyze the edge definition, brightness contrast and other parameters of the image to realize the use of machine learning algorithm to monitor the details of the image in real time, evaluate the changes of image resolution and signal-to-noise ratio, and realize the effective adjustment of the diaphragm aperture and the optimization of the image resolution and signal-to-noise ratio. The analysis of the imaging resolution and signal-to-noise ratio of the real-time detection image by the image monitoring device 50 can be specifically evaluated by the detail analysis of the image. For example, the resolution can use Laplace transform or gradient analysis method to calculate the sharpness or detail degree of the image. High-resolution image shows more details, and low-resolution image is blurred or lacks details.

[0094] Based on this, in the control method provided by the above embodiment, the imaging quality of the real-time detection image includes imaging resolution and signal-to-noise ratio. The system at least according to the imaging quality of the real-time detection image, feedback adjusts the diaphragm aperture of the adjustable diaphragm to make the real-time detection image reach the preset imaging quality standard, which can be specifically set as:

[0095] S141, in the model application stage, input the imaging resolution and signal-to-noise ratio of the real-time detection image into the machine learning algorithm model which is pre-trained to obtain a target diaphragm aperture which meets the target imaging quality standard, and control the adjustable diaphragm to adjust to the target diaphragm aperture.

[0096] Furthermore, the skilled person will also understand that the above embodiments are essentially based on a machine learning algorithm model to obtain a real-time target aperture according to real-time imaging resolution and signal-to-noise ratio. The machine learning algorithm model needs to be trained in advance so that the output target aperture can ensure that the system meets the requirements of the imaging quality standard. Therefore, the control method can further set the following steps in advance:

[0097] In the model training phase, a machine learning algorithm model is established;

[0098] Obtain the detection image under different apertures;

[0099] Use edge detection and / or texture analysis feature extraction technology to extract the imaging resolution and signal-to-noise ratio of the detection image;

[0100] On the basis of the imaging resolution and signal-to-noise ratio of the detection image, the target aperture that meets the target imaging quality standard is obtained by experiment, and the training sample of the target aperture under different imaging resolutions and different signal-to-noise ratios is obtained;

[0101] Use the training sample to complete the training of the machine learning algorithm model.

[0102] The steps of the above model training phase are explained in detail as follows:

[0103] The training process of the machine learning algorithm model first needs data collection and preprocessing steps: specifically, when the system starts, preliminary imaging data is collected, including images under different apertures. Preprocess these image data, such as denoising, contrast enhancement, standardizing image size, etc., to ensure data quality. Then a feature extraction step is needed: key features of the image are extracted by using image processing techniques (such as edge detection, texture analysis, etc.), such as resolution, contrast, distortion, etc. The feature vector includes: image sharpness (resolution), distortion degree (such as distortion, blur), brightness uniformity, etc. The machine learning model can use these feature vectors and their corresponding aperture values to train the machine learning model, such as support vector machine (SVM), random forest or neural network model. The model will learn the relationship between image features and aperture. During the training process, the model will calculate the mapping of each image feature and aperture, and optimize the aperture adjustment strategy. For the trained model, in the application stage, that is, in the real-time imaging process, the system will continuously analyze the image and extract the features. According to these features, the machine learning model will predict the best aperture of the current image. If the current imaging quality is lower than the preset standard, the model will instruct the system to adjust the aperture to optimize the imaging.

[0104] With reference to the above, the control method can further comprise the following steps: Figure 1On the basis of the above embodiment, the OCT system can also optionally include a wavefront sensor 60 located on the optical path between the adjustable diaphragm 20 and the sample to be measured; the wavefront sensor 60 is used to measure the wavefront aberration of the sample light in real time. The control system is also used to adjust the diaphragm aperture of the adjustable diaphragm 20 in real time according to the wavefront aberration of the sample light, so that the wavefront aberration of the sample light reaches the preset wavefront aberration standard.

[0105] In this embodiment, the wavefront sensor 60 detects the wavefront shape of the light beam, especially the phase, focus and distortion of the light beam, and can feedback the information of the light beam shape to help optimize the imaging quality. The wavefront sensor 60 is used to detect the wavefront shape of the light beam before it enters the sample to be measured, and the light beam quality is adjusted through the feedback mechanism. The main function of this embodiment is to detect and correct the distortion of the light beam, so as to improve the imaging accuracy of the system. The wavefront sensor 60 can be arranged in the optical path of the system, which can be located before or after the interferometer 30. The specific position depends on the design of the system. The ideal setting position can be after the adjustable diaphragm 20 and before the sample to be measured, so as to detect and correct the light beam before it enters the sample.

[0106] Figure 12 is a flow chart of another control method of the optical coherence tomography system with adjustable diaphragm provided by the embodiment of the present application, referring to Figure 12 The control method provided by the present application can include the following steps:

[0107] S210, control the light source to emit original laser; wherein the adjustable diaphragm adjusts the original laser by changing the diaphragm aperture to obtain adjusted laser; the interferometer splits the adjusted laser into reference light and sample light; the reference arm transmits the reference light and feeds back the reflected light of the reference light to the interferometer; the sample arm transmits the sample light to the sample to be measured to form sample reflected light and feed back to the interferometer; the interferometer receives the sample reflected light to generate interference with the reflected light of the reference light to form an interference signal.

[0108] S220, control the wavefront sensor to measure the wavefront aberration of the sample light in real time;

[0109] S230, adjust the diaphragm aperture of the adjustable diaphragm in real time according to the wavefront aberration of the sample light, so that the wavefront aberration of the sample light reaches the preset wavefront aberration standard.

[0110] S240, control the detector to reconstruct the image according to the interference signal to obtain a real-time detection image.

[0111] S250, control the image monitoring device to monitor the real-time detection image and analyze the imaging quality of the real-time detection image.

[0112] S261. In the model application stage, the imaging resolution and signal-to-noise ratio of the real-time detected image are input into the pre-trained machine learning algorithm model to obtain the target aperture that meets the target imaging quality standard, and the adjustable aperture is controlled to be adjusted to the target aperture.

[0113] In steps S230 and S240, the essence is to use wavefront sensor 60 to measure the distortion of the transmitted light wave in real time. Wavefront sensor 60 can detect aberrations, including spherical aberration, chromatic aberration, and other optical errors. Wavefront sensor 60 transmits the distortion information to an adaptive optics algorithm. The control system then uses the adaptive optics algorithm to analyze the wavefront distortion using a mathematical model (such as a Zernike polynomial) and evaluate the aberrations of the current optical system. This algorithm generates an optimized control signal based on the distortion data to adjust the shape or position of optical elements (such as mirrors, lenses, or apertures) in real time to reduce aberrations.

[0114] More specifically, the wavefront aberration of the sample light can include wavefront distortion. The control system is also used to adjust the aperture of the adjustable stop 20 in real time according to an adaptive optics algorithm so that the wavefront distortion of the sample light meets a preset wavefront distortion standard. The wavefront sensor 60 detects the wavefront distortion, which can be evaluated by comparing the geometric contrast between the actual image and the ideal image. For example, image contrast, edge sharpness, or geometric distortion measures (such as shape distortion, straight line curvature) can be used to quantify the distortion. In this embodiment, the presence of optical distortion is determined by the feedback information from the wavefront sensor 60. If the distortion is large, the system can adaptively adjust the aperture of the stop to optimize the beam quality.

[0115] Based on this, in the control method provided in the previous embodiment, the wavefront aberration of the sample light may include wavefront distortion. Therefore, step S230, which involves adjusting the aperture of the adjustable aperture in real time according to the wavefront aberration of the sample light to ensure that the wavefront aberration of the sample light reaches a preset wavefront aberration standard, can be specifically set as follows:

[0116] S231. Based on the adaptive optics algorithm, the aperture of the adjustable aperture is adjusted in real time so that the wavefront distortion of the sample light reaches the preset wavefront distortion standard.

[0117] It is understood that in this embodiment, by combining machine learning and adaptive optics algorithms, the control system receives image quality parameters such as imaging resolution, signal-to-noise ratio, and distortion level after each imaging process. If the image quality is substandard (e.g., low resolution or excessive distortion), the control system automatically adjusts the aperture size of the adjustable aperture 20. When the resolution is insufficient, the aperture size may be increased to improve the acquisition of more details; if the distortion is too large, the aperture size may be reduced to improve image sharpness and reduce optical errors.

[0118] To sum up, the embodiment of the present application focuses on solving the core scientific problem of how to realize low-cost, high adaptability and physically real high-resolution imaging in the field of optical coherence tomography without sacrificing imaging depth and increasing system complexity. The technical breakthrough is of great significance to promote the popularization of OCT technology in clinical medical treatment, industrial detection and scientific research fields.

[0119] It should be noted that the above are only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments, mutual combinations and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. An optical coherence tomography system with adjustable aperture, characterized in that, include: Light source, used to emit the original laser; An adjustable aperture is used to change the aperture diameter to adjust the original laser and obtain an adjusted laser. An interferometer is used to split the modulated laser beam into a reference beam and a sample beam; A reference arm is used to transmit the reference light and feed back the reflected light of the reference light to the interferometer; A sample arm is used to transmit the sample light to the sample to form a sample reflected light and feed it back to the interferometer; wherein, the interferometer is also used to receive the sample reflected light to interfere with the reflected light of the reference light to form an interference signal; The detector is used to reconstruct the image based on the interference signal to obtain a real-time detection image; An image monitoring device is used to monitor the real-time detection image and analyze the imaging quality of the real-time detection image. The control system is used to adjust the aperture of the adjustable aperture based on the imaging quality of the real-time detected image, so that the real-time detected image reaches a preset imaging quality standard.

2. The tomographic scanning system of claim 1, wherein, The imaging quality of the real-time detected image includes imaging resolution and signal-to-noise ratio; The control system is also used to input the imaging resolution and signal-to-noise ratio of the real-time detected image into a pre-trained machine learning algorithm model to obtain the target aperture that meets the target imaging quality standard, and to control the adjustable aperture to be adjusted to the target aperture.

3. The tomographic scanning system of claim 1, wherein, It also includes a wavefront sensor, located in the optical path between the adjustable aperture and the sample to be tested; The wavefront sensor is used to measure the wavefront aberration of the sample light in real time; The control system is also used to adjust the aperture of the adjustable aperture in real time according to the wavefront aberration of the sample light, so that the wavefront aberration of the sample light reaches the preset wavefront aberration standard.

4. The tomographic scanning system of claim 3, wherein, The wavefront aberration of the sample light includes wavefront distortion; The control system is also used to adjust the aperture of the adjustable aperture in real time according to an adaptive optics algorithm so that the wavefront distortion of the sample light reaches a preset wavefront distortion standard.

5. The tomographic scanning system of claim 1, wherein, The adjustable aperture includes a drive motor, a drive ring, and multiple rotating blades; The plurality of rotating blades are arranged in a circumferential stack around the optical axis, and the edges of the rotating blades overlap to form an adjustable aperture. The rotating blades are provided with a fixed axis and a moving shaft, and the moving shaft is rotatably connected to the drive ring. The drive motor is used to drive the drive ring to rotate, so as to drive each of the rotating blades to rotate around their respective fixed axes through the moving shaft, thereby changing the degree of edge overlap of adjacent rotating blades and obtaining different aperture diameters.

6. A method of controlling an optical coherence tomography system with adjustable aperture, characterized in that, Applied to the adjustable-aperture optical coherence tomography system as described in any one of claims 1-5; The control method includes: The system controls the emission of a raw laser from the light source; wherein, the adjustable aperture adjusts the raw laser by changing its aperture to obtain an adjusted laser; the interferometer splits the adjusted laser into a reference beam and a sample beam; the reference arm transmits the reference beam and feeds back the reflected light of the reference beam to the interferometer; the sample arm transmits the sample beam to the sample to form a sample reflected beam and feeds it back to the interferometer; the interferometer receives the sample reflected beam and interferes with the reflected light of the reference beam to form an interference signal; The detector is controlled to reconstruct the image based on the interference signal to obtain a real-time detection image; The image monitoring device is controlled to monitor the real-time detection image and analyze the imaging quality of the real-time detection image. Based at least on the imaging quality of the real-time detected image, the aperture of the adjustable aperture is adjusted to ensure that the real-time detected image meets a preset imaging quality standard.

7. The control method according to claim 6, characterized by, The imaging quality of the real-time detected image includes imaging resolution and signal-to-noise ratio; Based at least on the imaging quality of the real-time detected image, the aperture of the adjustable aperture is adjusted in response to feedback, so that the real-time detected image meets a preset imaging quality standard, including: During the model application phase, the imaging resolution and signal-to-noise ratio of the real-time detected image are input into a pre-trained machine learning algorithm model to obtain the target aperture that meets the target imaging quality standard, and the adjustable aperture is controlled to be adjusted to the target aperture.

8. The control method according to claim 7, characterized by, The control method further includes: During the model training phase, a machine learning algorithm model is established; Acquire detection images under different aperture sizes; The imaging resolution and signal-to-noise ratio of the detected image are extracted using feature extraction techniques based on edge detection and / or texture analysis. Based on the imaging resolution and signal-to-noise ratio of the detected image, the target aperture that meets the target imaging quality standard was experimentally obtained, and training samples of target aperture under different imaging resolutions and different signal-to-noise ratios were obtained. The machine learning algorithm model is trained using the training samples.

9. The control method according to claim 6, characterized in that, The optical coherence tomography system also includes a wavefront sensor located in the optical path between the adjustable aperture and the sample to be tested; The control method further includes: The wavefront sensor is controlled to measure the wavefront aberration of the sample light in real time. Based on the wavefront aberration of the sample light, the aperture of the adjustable aperture is adjusted in real time to make the wavefront aberration of the sample light reach the preset wavefront aberration standard.

10. The control method according to claim 9, characterized in that, The wavefront aberration of the sample light includes wavefront distortion; Based on the wavefront aberration of the sample light, the aperture of the adjustable aperture is adjusted in real time to ensure that the wavefront aberration of the sample light meets a preset wavefront aberration standard, including: According to the adaptive optics algorithm, the aperture of the adjustable aperture is adjusted in real time so that the wavefront distortion of the sample light reaches the preset wavefront distortion standard.

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