CN111543959B - Coherent chromatography system and reference wavefront correction method, device and equipment thereof - Google Patents
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Abstract
The invention discloses an optical coherence tomography system, which comprises a light source, an interferometer, a photoelectric detector and a temperature control device, wherein a reference arm in the interferometer comprises a spherical reflector; wherein, the back of the spherical reflector is provided with a rubber pad in a fitting manner; a plurality of heating sheets are uniformly arranged on the surface of the rubber mat, which is far away from the spherical reflector; each heating sheet is connected with a temperature control device; the temperature control device is used for controlling each heating plate to heat according to the interference fringe contrast collected by the photoelectric detector, and the spherical reflector is heated and deformed so that the interference fringe contrast detected by the photoelectric detector reaches the preset contrast. Reference arm adopts the spherical reflector in this application, can be directly to the spherical wave reflection of incident, and the back sets up the heating plate and makes the spherical reflector shape of face can change, compensates the correction to the light wave of incident, improves the interference fringe contrast ratio. The application also provides a reference wavefront correction method, a device and equipment of the optical coherence tomography system, and the method, the device and the equipment have the beneficial effects.
Description
Technical Field
The application relates to the technical field of optical coherence layer imaging, in particular to an optical coherence tomography system and a reference wavefront correction method, device and equipment thereof.
Background
Optical Coherence Tomography (OCT) is a new three-dimensional tomography technology developed gradually in the 90 s of the 20 th century. OCT obtains the chromatographic capacity in the depth direction based on the principle of low coherence interference, and can reconstruct a two-dimensional or three-dimensional image of the internal structure of biological tissue or material through scanning, wherein the signal contrast of the OCT derives from the spatial change of optical reflection (scattering) characteristics in the biological tissue or material. Tissue features of optical tomographic images obtained by the coherence tomography system are used to determine the target to be identified for diagnosis. Compared with the conventional imaging means, the optical coherence tomography has unique advantages, the imaging effect of the optical coherence tomography is close to pathology, and the optical coherence tomography has the advantages of non-invasive and non-radiative properties, real-time observation of living bodies, high resolution (16 micrometers), in-tissue depth imaging, 3D image data and the like.
As shown in fig. 1, fig. 1 is a schematic diagram of a frame structure of a conventional optical coherence tomography system in the prior art, in fig. 1, a light beam emitted from a low coherence light source 1 is transmitted to an optical fiber coupler 2 by light, and is divided into two paths of light, one path of light is transmitted to a reference arm 3 and reflected, and then transmitted to the optical fiber coupler 2 again, and the other path of light is incident to a human tissue 5, and is reflected by different tissue layers of the human tissue, and then returns to the optical fiber coupler 2 along the original path; because the optical paths of the light beam reflected back to the optical fiber coupler 2 through the reference arm 3 and the light beam reflected back to the optical fiber coupler 2 through the human tissue 5 are different, the two light beams can interfere, an interference image is detected through the spectrometer 4, and a human tissue image can be obtained based on the interference image.
As can be seen from fig. 1, the reference arm 3 mainly comprises a collimating lens group 31 and a reflecting plane mirror 32, because the light beam transmitted to the reference arm 3 by the optical fiber is a divergent light beam, and needs to be converted into a parallel light beam by the collimating lens group 31, and then reflected by the reflecting plane mirror 32 to ensure that the light beam returns along the original optical path and is transmitted to the optical fiber coupler 2. Obviously, the end of the optical fiber in the optical path needs to be located at the focal point of the collimating lens group 31, and the optical axis of the collimating lens group 31 needs to be perpendicular to the reflecting plane mirror 32, however, in the practical application process, the alignment accuracy of the relative positions among the end of the optical fiber, the collimating lens group 31 and the reflecting plane mirror 32 is not necessarily perfect, and in the carrying process of the optical coherence tomography system, the alignment accuracy among the components is reduced, and further the conduction of the light beam is affected, so that the contrast of the interference fringe is reduced, and the use performance of the optical coherence tomography system is affected.
Disclosure of Invention
The invention aims to provide an optical coherence tomography system and a reference wavefront correction method, device and equipment thereof, which improve the contrast of interference fringes of the optical coherence tomography system and further improve the accuracy of human tissue detection.
In order to solve the technical problem, the invention provides an optical coherence tomography system, which comprises a light source, an interferometer, a photoelectric detector and a temperature control device, wherein a reference arm in the interferometer comprises a spherical reflector;
the back surface of the spherical reflector is provided with a rubber pad in a fitting manner; a plurality of heating sheets are uniformly arranged on the surface of the rubber mat, which is far away from the spherical reflector; each heating sheet is connected with a temperature control device;
the temperature control device is used for controlling the heating of each heating plate according to the interference fringe contrast ratio collected by the photoelectric detector, and the spherical reflector is deformed by heating, so that the interference fringe contrast ratio detected by the photoelectric detector reaches the preset contrast ratio.
Optionally, the spherical mirror is a K9 glass aluminized mirror.
Optionally, the rubber mat is an RTV rubber mat.
Optionally, the thickness of the rubber pad satisfies:
wherein t is the thickness of the RTV rubber mat,
is the radius of the spherical mirror and is,
as the coefficient of thermal expansion of the heat patch,
is the coefficient of thermal expansion of the spherical mirror,
for the thermal expansion coefficient of the RTV rubber mat under load
Optionally, the heating sheet is a copper sheet or an aluminum sheet.
The present application further provides a reference wavefront correction method for an optical coherence tomography system, which is applied to the optical coherence tomography system described in any one of the above, and includes:
obtaining the contrast of interference fringes according to the interference fringes detected by the photoelectric detector;
determining the heating power of each heating plate according to the interference fringe contrast;
and heating each heating plate according to the heating power, and repeatedly executing the step of obtaining the contrast ratio of the interference fringes according to the interference fringes detected by the photoelectric detector until the contrast ratio of the interference fringes reaches a preset contrast ratio.
Optionally, determining the heating power of each heating plate according to the interference fringe contrast comprises:
acquiring interference fringe contrast data of the spherical reflector corresponding to different heating powers of each heating plate in advance;
determining the corresponding relation between different heating powers and interference fringe contrast ratios based on neural network learning according to different heating powers of the heating sheets and interference fringe contrast ratio data corresponding to the heating powers;
and determining the heating power of each heating plate according to the corresponding relation and the current interference fringe contrast.
Optionally, determining the heating power of each heating plate according to the interference fringe contrast comprises:
based on a parallel gradient descent algorithm in advance, the formula of the heating power is determined as follows:
and determining the heating power of each heating sheet according to the heating power.
The present application further provides a reference wavefront correction device of an optical coherence tomography system, which is applied to the optical coherence tomography system as described in any one of the above, and includes:
the contrast acquisition module is used for acquiring the contrast of the interference fringes according to the interference fringes detected by the photoelectric detector;
the power determining module is used for determining the heating power of each heating plate according to the interference fringe contrast;
and the control heating module is used for heating each heating sheet according to the heating power and repeatedly executing the step of acquiring the contrast of the interference fringes detected by the photoelectric detector until the contrast of the interference fringes detected by the photoelectric detector reaches a preset contrast.
The application also provides a reference wavefront correction device of an optical coherence tomography system, which is applied to the optical coherence tomography system as described in any one of the above items, and comprises:
a memory for storing a computer program;
a processor for executing the computer program for implementing the operational steps of the reference wavefront correction method of an optical coherence tomography system as described in any of the above.
The optical coherence tomography system provided by the invention comprises a light source, an interferometer, a photoelectric detector and a temperature control device, wherein a reference arm in the interferometer comprises a spherical reflector; wherein, the back of the spherical reflector is provided with a rubber pad in a fitting manner; a plurality of heating sheets are uniformly arranged on the surface of the rubber mat, which is far away from the spherical reflector; each heating sheet is connected with a temperature control device; the temperature control device is used for controlling each heating plate to heat according to the interference fringe contrast collected by the photoelectric detector, and the spherical reflector is heated and deformed so that the interference fringe contrast detected by the photoelectric detector reaches the preset contrast.
In the optical coherence tomography system provided by the application, a reference arm formed by combining a collimating lens group and a plane reflector in the conventional technology is replaced by a spherical reflector, so that the spherical reflector can directly reflect incident spherical waves without collimating the light waves through the collimating lens group, the optical rate structure is simplified to a great extent, and the light beams are prevented from generating deviation in the light path transmission process and influencing the contrast of subsequent interference fringes; and the back of the spherical reflector is also provided with a heating sheet, and the surface shape of the spherical reflector is finely adjusted by heating through the heating sheet, so that the spherical reflector compensates the phase of the incident spherical light wave, and the contrast of subsequent interference fringes is improved.
The application also provides an optical coherence tomography method, an optical coherence tomography device and an optical coherence tomography equipment, which have the beneficial effects.
Drawings
In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a schematic diagram of a frame structure of a conventional optical coherence tomography system in the prior art;
FIG. 2 is a schematic structural diagram of an optical coherence tomography system provided by an embodiment of the present application;
fig. 3 is a schematic structural diagram of a back surface of a spherical mirror according to an embodiment of the present disclosure;
FIG. 4 is a graph of the shape factor versus correction factor for RTV cushion material;
FIG. 5 is a schematic flow chart of a reference wavefront correction method of an optical coherence tomography system according to an embodiment of the present disclosure;
fig. 6 is a block diagram of a reference wavefront correction apparatus of an optical coherence tomography system according to an embodiment of the present invention.
Detailed Description
The core of the invention is to provide a technical scheme of optical coherence tomography, which can improve the contrast of the generated interference fringe to a great extent, thereby improving the definition of the human tissue image detected by the optical coherence tomography in the practical application process.
In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 2 and fig. 3, fig. 2 is a schematic structural diagram of an optical coherence tomography system provided in an embodiment of the present application, and fig. 3 is a schematic structural diagram of a back surface of a spherical mirror provided in an embodiment of the present application. The system may include:
a light source, specifically, a low coherence laser light source 1;
the interferometer may specifically include components such as a reference arm 3, a fiber coupler 2, etc.;
the connection between the photodetector and the light source, the components referring to fig. 3 and the optical fiber coupler 2 is the same as that in the prior art in fig. 1, and the connection is not described herein again.
The interferometer also comprises a temperature control device 6, and a reference arm 3 in the interferometer comprises a spherical reflector 33;
wherein, the back of the spherical reflector 33 is provided with a rubber pad 34; the surface of the rubber pad 34 departing from the spherical reflector 33 is uniformly provided with a plurality of heating sheets 35; each heating sheet 35 is connected with the temperature control device 6;
the temperature control device 6 is used for controlling each heating plate to heat according to the interference fringe contrast collected by the photoelectric detector, and the spherical reflector 33 can deform when being heated, so that the interference fringe contrast detected by the photoelectric detector reaches the preset contrast.
Specifically, the heating sheet 35 in this embodiment may be a copper sheet or an aluminum sheet, which generates heat when energized.
It should be noted that, in the practical application process of the optical coherence tomography system, the light beam generated by the light source can be transmitted to the optical fiber coupler 2 through the optical fiber, and is divided into two paths of light waves by the optical fiber coupler 2, one of the light waves is transmitted to the human tissue 5 through the optical fiber, and the other light wave is transmitted to the reference arm 3 through the optical fiber; the light wave incident into the reference arm 3 is normally a spherical light wave, so the shape of the spherical mirror 33 in the reference arm 3 and the shape of the wavefront of the light beam are the closest in this embodiment, so that the light wave incident into the reference arm 3 can return back along the original path to the maximum extent.
Compared with the technical scheme that the quasi-lens group 31 is adopted to convert spherical light waves into parallel light beams firstly and the reflected light beams return along the original light path through the plane mirror 32 in the prior art, the structure of the reference arm 3 in the embodiment is simpler, so that in the practical application process, the problem that the wavefront of the light beam reflected by the reference arm 3 is changed and the contrast of interference fringes is low due to the fact that the relative positions of devices such as the quasi-lens group and the plane mirror are shifted and cannot be accurately calibrated due to the long-time use of an optical coherence tomography system is solved to a great extent.
In this embodiment, it is also considered that, during the transmission of the light beam, since the light beam needs to pass through a plurality of optical elements, the optical fiber coupler 2 is prone to generate dispersion during the stretch forming process, and in the actual optical path, there are also problems of non-uniform pupil illumination, and the like, which finally also causes the contrast of the formed interference fringes to be reduced, and affects the detection effect of human tissue.
Therefore, in this embodiment, a rubber pad 34 is further attached to the back surface of the spherical mirror 33, a heating sheet 35 is disposed on the rubber pad 34, the heating sheet 35 is connected to the temperature control device 6, the heating sheet 35 can be heated by the temperature control device 6, so that heat generated by heating the heating sheet 35 is conducted to the spherical mirror 33 through the rubber pad 34, the spherical mirror 33 is heated to generate a slight deformation, and further the surface shape of the spherical mirror 33 is changed, so that the changed surface shape of the spherical mirror 33 can perform wavefront correction compensation on incident light waves, thereby achieving large-range non-dispersive focusing and wavefront astigmatism correction of the reference arm 3 to a certain extent, achieving compensation of non-uniform illumination of pupils in the light path, improving contrast of interference fringes, and greatly improving the definition of human body images detected and collected by the optical coherence tomography system, the accuracy of the detection result is improved.
Alternatively, the spherical mirror 33 in the above embodiment may be specifically a K9 glass-coated aluminum mirror.
For the rubber pad 34 in the above embodiment, an RTV rubber pad having elasticity may be specifically adopted to accommodate the deformation of the spherical mirror 33.
The size and thickness of the RTV rubber pad as an elastomer supporting structure play a crucial role in controlling the deformation and displacement of the spherical mirror, and the shape factor S of the elastomer in design factors greatly influences the mechanical properties of the elastomer, and can be defined as:
wherein, the loaded area (loadarea) of the RTV rubber mat is set to be circular,
the radius of the loaded area, t is the thickness of the RTV rubber mat. Experiments prove that the thermal expansion coefficient of the constrained RTV rubber mat is obviously different from that of the material, so that a thermal expansion correction coefficient is introduced
The relationship of the thermal expansion coefficients can be expressed as:
(ii) a Wherein,
for the thermal expansion coefficient of the RTV cushion material itself,
the thermal expansion coefficient of the RTV rubber mat under the load condition.
Correction coefficient of thermal expansion determined by shape factor S
It can be expressed as:
(ii) a Wherein
In order to change the thickness of the RTV rubber mat under the thermal load,
is the amount of change in operating temperature.
As shown in fig. 4, fig. 4 is a graph showing the relationship between the shape factor and the correction coefficient of the RTV cushion material, and different S values correspond to different thermal expansion coefficient correction factors. Therefore, the thermal expansion coefficient of the RTV rubber mat after being corrected has stronger correlation with the shape factor S, and according to the shape factor formula:
it is known that this form factor is affected by the RTV cushion.
The thickness of the RTV cushion in this embodiment can be expressed by the Baylar equation, the Deluzio equation, and the Muench equation. Finally, the thickness of the RTV rubber mat can be determined
；
Wherein
Is the radius of the lens or lenses,
in order to obtain the coefficient of thermal expansion of the aluminum sheet,
in order to be the thermal expansion coefficient of the mirror,
is the coefficient of thermal expansion of the RTV gasket under load.
The present application further provides an embodiment of a reference wavefront correction method for an optical coherence tomography system, which is applied to the optical coherence tomography system described in any of the above embodiments, as shown in fig. 5, fig. 5 is a schematic flow chart of the reference wavefront correction method for the optical coherence tomography system provided in the embodiment of the present application, where the correction method may include:
s1: and obtaining the contrast of the interference fringes according to the interference fringes detected by the photoelectric detector.
The fringe contrast is used to measure the sharpness of the fringes near a certain point in the interference field. As known from the optical principle, the intensity of the interference fringe can be expressed as:
wherein,
is the wavelength of the coherent light,
and
is the incident light intensity of two interference arms in the interferometer,
is a complex phase dryness factor, and is
(ii) a Phase positionIs composed of
，
In order to be the target source phase,
for two interference arms
And
the difference introduces a phase. The contrast (contrast) or visibility (visibility) of the interference fringes can be expressed as a ratio (attenuation) of the amplitude of the fringes to the total background illumination, and can be expressed as:
；
from the above formula, the contrast of interference fringes depends on the following three factors: light source size, non-monochromaticity of the light source, and amplitude ratio of the two coherent light waves.
The above formula is a determinant formula of the contrast of the interference fringes, and may also be considered as a formula that the contrast of the interference fringes should satisfy in a theoretical state, but in a practical application process, the interference fringes may cause deviation of the intensity, the position and the theoretical condition of the interference fringes due to the fact that the interference light beams are deviated from the theoretical state in the conduction process, the phase, the optical path and the like. Therefore, in practical application, in the embodiment, the contrast of the interference fringe is determined based on the interference fringe actually obtained, and the ratio of the difference between the maximum value and the minimum value of the light intensity of the interference fringe to the sum of the maximum value and the minimum value may be used, that is:
wherein
is the maximum value of the light intensity of the interference fringe,
Is the minimum value of the light intensity of the interference fringes.
S2: and determining the heating power of each heating plate according to the contrast ratio of the interference fringes.
S3: and heating the heating sheets according to the heating power.
Specifically, each heating sheet is heated, so that the spherical reflector can be slightly deformed, the surface shape of the spherical reflector is changed, the spherical reflector corrects and compensates the wavefront phase, optical path difference and the like of incident light waves, the deviation of the light waves in the transmission process is eliminated, and the contrast of interference fringes is higher when the light waves reflected by the reference arm interfere with the light waves reflected by incident human tissues.
S4: obtaining the contrast of interference fringes according to the interference fringes detected by the photoelectric detector;
s5: and judging whether the contrast of the interference fringes reaches a preset contrast, if so, finishing the correction, and if not, entering S2.
In this embodiment, the heating adjustment of the heating sheet is a trial-and-error adjustment mode. Firstly, obtaining the contrast of interference fringes under the condition that each heating plate is heated, if the contrast of the interference fringes does not reach the preset contrast, setting the heating power of each heating plate based on the current contrast of the interference fringes and heating each heating plate, collecting the contrast of the interference fringes under the heating power again, if the contrast of the interference fringes reaches the preset contrast, finishing calibration, if the contrast of the interference fringes does not reach the preset contrast, continuously increasing the heating power of the heating plates, repeating the process, and finally enabling the contrast of the interference fringes to reach the requirement, wherein correspondingly, the human tissue image obtained based on the contrast of the interference fringes is clearer.
In an optional embodiment of the present application, determining the heating power per heating of each heating sheet according to the interference fringe contrast may include:
acquiring interference fringe contrast data of the spherical reflector corresponding to different heating powers of each heating plate in advance;
determining the corresponding relation between different heating powers and interference fringe contrast ratios based on neural network learning according to different heating powers of the heating sheets and interference fringe contrast ratio data corresponding to the heating powers;
and determining the heating power of each heating plate according to the corresponding relation and the current interference fringe contrast.
Specifically, each heating sheet can be heated individually in advance to obtain different heating powers and corresponding interference fringe contrasts of each heating sheet, the heating powers and the corresponding interference fringe contrasts of each heating sheet are used as sample data, neural network training is performed, and finally the corresponding relation between the heating powers and the interference fringe contrasts is determined. In practical applications, the magnitude of the heating power of the current heating plate can be determined according to the corresponding relationship based on the current interference fringe contrast and the corresponding relationship.
In the embodiment, a wavelet neural network can be specifically adopted for training, the wavelet neural network combines the characteristics of wavelet transformation multi-scale representation, and meanwhile, the characteristics of good generalization capability and strong nonlinear mapping capability of the neural network are reserved. A system error (gravity, temperature, airflow, vibration, an actuating mechanism error, an optical element surface shape error, a polarization error and light intensity flicker) model is built end to end on the basis of a deep learning algorithm, calibration of the system is achieved, and pressure of hardware implementation is reduced.
In another optional embodiment of the present application, determining the heating power per heating of each heating sheet according to the interference fringe contrast may include:
based on a parallel gradient descent algorithm in advance, the formula of the heating power is determined as follows:
and determining the heating power of each heating plate according to the heating power.
Specifically, the derivation principle of the heating power formula is as follows:
let the contrast of the stripes be
Increasing disturbance electric power of electric heating sheet
The variation of the performance index obtained after the test is as follows
Since no energy surge occurs in practical engineering applications and scientific research practices, system performance indices (contrast) are assumed
Conductibility, which can be obtained by taylor expansion:
Multiplying the left and right sides simultaneously by using a gradient for obtaining a decrease in the performance index
If desired, the following are obtained:
；
suppose that
Each element in the composition is independently and identically distributed, and can be obtained
Wherein,
is composed of
The variance of (2) can be used for obtaining the unbiased estimation of the descending gradient of the evaluation index through a statistical rule
；
Based on the method, the following steps can be obtained:
(ii) a Wherein,
the heating power for heating the (n + 1) th heating plate,
the heating power for heating the ith heating plate for the nth time,
is the change value of the contrast ratio after the nth heating,
the heating power change value for the heating of the ith heating plate for the nth time.
The parallel gradient descent algorithm is a method for approximating a gradient by obtaining estimation by means of mathematical statistics, a heating power formula is determined according to the parallel gradient descent algorithm, and a better convergence characteristic can be obtained by selecting reasonable disturbance electric power. And the parallel gradient descent algorithm is a method which relies on mathematical statistics to obtain an estimate to approximate the gradient.
In the following, reference wavefront correction devices of an optical coherence tomography system according to embodiments of the present invention are introduced, and reference wavefront correction devices of the optical coherence tomography system described below and reference wavefront correction methods of the optical coherence tomography system described above may be referred to correspondingly.
Fig. 6 is a block diagram of a reference wavefront correction apparatus of an optical coherence tomography system according to an embodiment of the present invention, which is applied to the optical coherence tomography system according to any embodiment of the present invention, and the reference wavefront correction apparatus of the optical coherence tomography system according to fig. 6 may include:
the contrast acquisition module 100 is configured to obtain a contrast of the interference fringes according to the interference fringes detected by the photodetector;
a power determining module 200, configured to determine the heating power of each heating plate according to the interference fringe contrast;
and the heating module 300 is controlled to heat each heating sheet according to the heating power, and repeatedly perform the step of acquiring the contrast of the interference fringes detected by the photoelectric detector until the contrast of the interference fringes detected by the photoelectric detector reaches a preset contrast.
The reference wavefront correction device of the optical coherence tomography system of this embodiment is configured to implement the aforementioned reference wavefront correction method of the optical coherence tomography system, and therefore a specific implementation manner of the reference wavefront correction device of the optical coherence tomography system may be found in the foregoing embodiment portions of the reference wavefront correction method of the optical coherence tomography system, for example, the contrast acquisition module 100, the power determination module 200, and the control heating module 300, which are configured to implement steps S1, S2, S3, and S4 in the reference wavefront correction method of the optical coherence tomography system, so that the specific implementation manner thereof may refer to descriptions of corresponding respective partial embodiments, and is not repeated herein.
The present application further provides a reference wavefront correction device of an optical coherence tomography system, applied to the optical coherence tomography system according to any of the above embodiments, including:
a memory for storing a computer program;
a processor for executing the computer program for implementing the operational steps of the reference wavefront correction method of an optical coherence tomography system as described in any of the embodiments.
In particular, the memory may be in particular a Random Access Memory (RAM), a memory, a Read Only Memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include elements inherent in the list. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. In addition, parts of the above technical solutions provided in the embodiments of the present application, which are consistent with the implementation principles of corresponding technical solutions in the prior art, are not described in detail so as to avoid redundant description.
The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (10)
1. An optical coherence tomography system comprises a light source, an interferometer and a photoelectric detector, and is characterized by further comprising a temperature control device, wherein a reference arm in the interferometer comprises a spherical reflector;
the back surface of the spherical reflector is provided with a rubber pad in a fitting manner; a plurality of heating sheets are uniformly arranged on the surface of the rubber mat, which is far away from the spherical reflector; each heating sheet is connected with the temperature control device;
the temperature control device is used for controlling the heating of each heating plate according to the interference fringe contrast ratio collected by the photoelectric detector, and the spherical reflector is deformed by heating, so that the interference fringe contrast ratio detected by the photoelectric detector reaches the preset contrast ratio.
2. The optical coherence tomography system of claim 1, wherein the spherical mirror is a K9 glass aluminized mirror.
3. The optical coherence tomography system of claim 1, wherein the gel pad is an RTV gel pad.
4. The optical coherence tomography system of claim 3, wherein the thickness of the gel pad is such that:
wherein t is the thickness of the RTV rubber mat,
is the radius of the spherical mirror and is,
as the coefficient of thermal expansion of the heat patch,
is the coefficient of thermal expansion of the spherical mirror,
is the thermal expansion coefficient of the RTV rubber mat under the load condition.
5. The optical coherence tomography system of claim 1, wherein the heating patch is a sheet of copper or aluminum.
6. A reference wavefront correction method of an optical coherence tomography system, applied to the optical coherence tomography system of any one of claims 1 to 5, comprising:
obtaining the contrast of interference fringes according to the interference fringes detected by the photoelectric detector;
determining the heating power of each heating plate according to the interference fringe contrast;
and heating each heating plate according to the heating power, and repeatedly executing the step of obtaining the contrast ratio of the interference fringes according to the interference fringes detected by the photoelectric detector until the contrast ratio of the interference fringes reaches a preset contrast ratio.
7. The method of reference wavefront calibration in an optical coherence tomography system of claim 6 wherein determining the heating power of each heater chip based on the interference fringe contrast comprises:
acquiring interference fringe contrast data of the spherical reflector corresponding to different heating powers of each heating plate in advance;
determining the corresponding relation between different heating powers and interference fringe contrast ratios based on neural network learning according to different heating powers of the heating sheets and interference fringe contrast ratio data corresponding to the heating powers;
and determining the heating power of each heating plate according to the corresponding relation and the current interference fringe contrast.
8. The method of reference wavefront calibration in an optical coherence tomography system of claim 6 wherein determining the heating power of each heater chip based on the interference fringe contrast comprises:
based on a parallel gradient descent algorithm in advance, the formula of the heating power is determined as follows:
and determining the heating power of each heating sheet according to the heating power.
9. A reference wavefront correction apparatus for an optical coherence tomography system, applied to the optical coherence tomography system of any one of claims 1 to 5, comprising:
the contrast acquisition module is used for acquiring the contrast of the interference fringes according to the interference fringes detected by the photoelectric detector;
the power determining module is used for determining the heating power of each heating plate according to the interference fringe contrast;
and the heating control module is used for heating each heating sheet according to the heating power and repeatedly executing the step of acquiring the contrast of the interference fringes detected by the photoelectric detector until the contrast of the interference fringes detected by the photoelectric detector reaches a preset contrast.
10. A reference wavefront correction apparatus of an optical coherence tomography system, applied to the optical coherence tomography system of any one of claims 1 to 5, comprising:
a memory for storing a computer program;
a processor for executing the computer program for carrying out the operating steps of the reference wavefront correction method of an optical coherence tomography system as claimed in any one of the claims 6 to 8.
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