Spectrum calibration method for linear view field spectral domain OCT (Optical Coherence Tomography) system

Abstract

The invention belongs to the field of optical coherence layer imaging, and particularly discloses a spectrum calibration method for a linear field spectral domain OCT (optical coherence tomography) system, which comprises the following steps: acquiring interference signal instantaneous phases corresponding to two optical path differences by adjusting a lifting platform at a sample mirror in the linear field spectral domain OCT system, and subtracting the interference signal instantaneous phases to obtain an instantaneous phase difference; based on the calibration light source, discrete spectral lines are generated on a detector through a sample arm in the shielding line view field spectral domain OCT system, and spectral intensity distribution corresponding to the calibration light source is obtained; calculating the sub-pixel position of the peak value of each spectral line and the instantaneous phase difference corresponding to the sub-pixel position based on the instantaneous phase difference and the spectral intensity distribution corresponding to the calibration light source; and based on the wave number and the instantaneous phase difference corresponding to each spectral line, determining a linear relationship between the instantaneous phase difference and the wave number through linear fitting, and calibrating the corresponding wave number based on the linear relationship. According to the method and the device, the linear field OCT spectrum calibration result with higher precision can be realized.

Description

Technical Field

[0001] The present application belongs to the field of optical coherence layer imaging, and more specifically, to a spectral calibration method for a line-view spectral domain OCT system. Background Art

[0002] Spectral-Domain Optical Coherence Tomography (SD-OCT) has been widely used in biomedical imaging and industrial inspection due to its non-destructive, high-resolution and no axial scanning characteristics. The line-field spectral domain OCT (LF-SD-OCT) system has achieved parallel acquisition of multiple A-Scans signals by virtue of the advantages of line-field illumination and high-speed array camera, thereby greatly improving the imaging speed. However, its imaging quality depends largely on the accuracy of spectral calibration. Traditional line-field spectral domain OCT systems generally calibrate the back-end imaging spectrometer separately, and use the known spectral line data of the calibration light source to directly fit the wavelength-pixel relationship with a polynomial. However, this method is usually limited by the order of the fitting polynomial: in order to obtain an accurate pixel-wavelength (or wavenumber) mapping, a polynomial of appropriate order needs to be selected for fitting. If the order is too low, it is difficult to describe the nonlinear changes of the spectrum; if the order is too high, overfitting may be introduced, amplifying the influence of noise. The selection of the polynomial order depends on experience and lacks physical meaning and objective judgment criteria. In addition, in the line-view spectral domain OCT system, the imaging spectrometer usually performs secondary imaging on the relay image transmitted back by the interferometer arm. The aberrations in the front-end interferometer arm and its installation errors may cause deviations between the actual spectral distribution and the calibrated spectral data. How to calibrate the line-view OCT spectrum with higher precision is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0003] In view of the defects of the prior art, the purpose of the present application is to effectively improve the calibration accuracy of the linear field OCT spectrum.

[0004] To achieve the above objectives, in a first aspect, the present application provides a spectral calibration method for a line-view spectral domain OCT system, comprising: The first optical path difference is obtained by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference , and subtract the instantaneous phases of the interference signals corresponding to the two optical path differences to obtain the instantaneous phase difference , the first optical path difference and the second optical path difference are different, Represents the pixel index of the detector in the line-field spectral domain OCT system; Based on the calibration light source, by blocking the sample arm in the line field spectral domain OCT system, discrete spectral lines are generated on the detector, and the spectral intensity distribution corresponding to the calibration light source is obtained. ; Based on the instantaneous phase difference Spectral intensity distribution corresponding to the calibration light source , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , Indicates the number of the spectral line; Based on the wave number corresponding to each spectral line and instantaneous phase difference , through linear fitting, determine the linear relationship between instantaneous phase difference and wave number, and calibrate based on the linear relationship The corresponding wave number .

[0005] In a possible implementation, the first optical path difference is obtained by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference ,include: The optical path difference is and The AC quantity of the interference signal is obtained at the position and ; AC quantity based on interference signal and , the complex interference signal is obtained by Hilbert transform and , unpacking the phase term of the complex interference signal to obtain and .

[0006] In one possible implementation, the sub-pixel position of the peak of each spectral line is calculated ,include: Based on the spectral intensity distribution corresponding to the calibration light source , the sub-pixel position of the peak of each spectral line is determined by the energy center of gravity method ECCM .

[0007] In one possible implementation, the sub-pixel position is calculated The corresponding instantaneous phase difference ,include: Sub-pixel position based on the peak of each spectral line , through Interpolate to determine sub-pixel position The corresponding instantaneous phase difference .

[0008] In a possible implementation, the spectral intensity distribution corresponding to the calibration light source is obtained. ,include: Based on the discrete spectral lines generated on the detector, the spectral intensity distribution corresponding to the calibration light source is determined by enhancing the spectral line signal. .

[0009] In a possible implementation, based on the linear relationship calibration The corresponding wave number After that, it also includes: By the first optical path difference The corresponding interference signal instantaneous phase Perform a first-order fit to determine the nonlinear term introduced by the dispersion mismatch between the two arms; or, The corresponding interference signal instantaneous phase Perform a first-order fit to determine the nonlinear term introduced by the dispersion mismatch between the two arms; Based on the nonlinear term, dispersion compensation is performed on the line-view spectral domain OCT system.

[0010] In a possible implementation, the method further includes: Calibrate different field of view channels along the target direction The corresponding wave number , the target direction is perpendicular to the direction of spectrum expansion on the detector image plane.

[0011] In a second aspect, the present application provides a spectral calibration device for a line-view spectral domain OCT system, comprising: The instantaneous phase difference acquisition module is used to obtain the first optical path difference by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference , and subtract the instantaneous phases of the interference signals corresponding to the two optical path differences to obtain the instantaneous phase difference , the first optical path difference and the second optical path difference are different, Represents the pixel index of the detector in the line-field spectral domain OCT system; The discrete spectral line generation module is used to generate discrete spectral lines on the detector based on the calibration light source by blocking the sample arm in the line field spectral domain OCT system, and obtain the spectral intensity distribution corresponding to the calibration light source. ; Spectral line peak sub-pixel position calculation module, used to calculate the peak position based on the instantaneous phase difference Spectral intensity distribution corresponding to the calibration light source , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , Indicates the number of the spectral line; Calibration module, used to calculate the wave number corresponding to each spectral line and instantaneous phase difference , through linear fitting, determine the linear relationship between instantaneous phase difference and wave number, and calibrate based on the linear relationship The corresponding wave number .

[0012] In a third aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method described in the first aspect or any possible implementation of the first aspect.

[0013] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method described in the first aspect or any possible implementation of the first aspect.

[0014] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: (1) By obtaining the instantaneous phase difference , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , can determine the linear relationship between the instantaneous phase difference and the wave number through linear fitting, and then calibrate based on the linear relationship The corresponding wave number This method can make full use of the phase information contained in the interference fringes and establish a more rigorous calibration model. It can eliminate the interference of the dispersion term caused by the dispersion mismatch between the two arms (reference arm and sample arm) during the calibration process, and take into account the offset between the spectral channels of different sampling points. The above calibration operation can be performed on each field of view, which can achieve higher-precision line-field OCT spectral calibration results.

[0015] (2) Considering that the energy of the calibration light source coupled into the system from the optical fiber is relatively weak, the calibration accuracy can be improved by enhancing the calibration light source signal.

[0016] (3) Analyze and evaluate the system’s dispersion, and then make software and hardware compensation to reduce interference caused by dispersion mismatch. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of a spectral calibration method for a line-view spectral domain OCT system provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of the spectrum calibration of the line field spectral domain OCT system provided in the embodiment of the present application; Figure 3 is a schematic diagram of adjusting the optical path difference of the sample arm provided in an embodiment of the present application; Figure 4 is a schematic diagram of interference fringes on the image plane at different optical path difference positions provided by an embodiment of the present application; Figure 5 is a light path diagram for generating fitting data points provided in an embodiment of the present application; Figure 6 It is a two-dimensional spectrum diagram formed on the image plane by the calibration light source provided in the embodiment of the present application; Figure 7 It is a structural schematic diagram of a spectral calibration device for a line-view spectral domain OCT system provided in an embodiment of the present application; Figure 8 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0018] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1 is a computer; 2 is a light source; 3 is a fiber collimator; 4 is a cylindrical lens; 5 is a beam splitter; 6 is a relay lens; 7 is an imaging spectrometer; 8 is an achromatic lens; 9 is a reference mirror; 10 is an objective lens; 11 is a sample mirror; 12 is a Z-axis lifting platform; 13 is a light baffle; 14 is an instantaneous phase difference acquisition module; 15 is a discrete spectrum line generation module; 16 is a spectrum line peak sub-pixel position calculation module; 17 is a calibration module. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, the first optical path difference and the second optical path difference are used to distinguish different optical path differences rather than to describe a specific order of the optical path differences.

[0021] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0022] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0023] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0024] Figure 1 is a flow chart of a spectral calibration method for a line-view spectral domain OCT system provided in an embodiment of the present application, such as Figure 1 As shown, the method includes the following steps S101 to S104.

[0025] Step S101, by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system, a first optical path difference is obtained. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference , and subtract the instantaneous phases of the interference signals corresponding to the two optical path differences to obtain the instantaneous phase difference , the first optical path difference and the second optical path difference are different, Represents the pixel index of the detector in the line-field spectral domain OCT system; Step S102, based on the calibration light source, by blocking the sample arm in the line field spectral domain OCT system, discrete spectral lines are generated on the detector, and the spectral intensity distribution corresponding to the calibration light source is obtained. ; Step S103, based on the instantaneous phase difference Spectral intensity distribution corresponding to the calibration light source , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , Indicates the number of the spectral line; Step S104: based on the wave numbers corresponding to each spectral line and instantaneous phase difference , through linear fitting, determine the linear relationship between instantaneous phase difference and wave number, and calibrate based on the linear relationship The corresponding wave number .

[0026] The working principle of the calibration method provided in this application is explained below.

[0027] Usually, the interference arm of the line-field spectral domain interferometric imaging system consists of a reference arm and a sample arm, and a cylindrical lens is introduced to form a line illumination on the sample surface. The imaging spectrometer can perform spectral imaging on the relay image of the sample at the line illumination, and then obtain the A-scan signal of each field of view by fast Fourier transforming the spectra of different field of view channels. Assuming that on the image plane of the two-dimensional array detector (hereinafter referred to as the detector) in the imaging spectrometer, the horizontal direction is the direction of spectral expansion, and the vertical direction corresponds to different field of view channels, then in this type of imaging system, it is necessary to find the following pixel index p and wave number for each row channel on the detector surface through spectral calibration The mapping relationship The calibration method proposed in this application is based on the phase change of interference fringes and is explained by taking the spectrum signal of the central visual field as an example.

[0028] Figure 2 A structural method for calibrating a line-view spectral domain interferometric imaging system is provided. The system includes a computer 1 for controlling and processing data and a line-view spectral domain interferometric imaging system (line-view spectral domain OCT system). The line-view spectral domain interferometric imaging system consists of a light source 2, a fiber collimator 3, a cylindrical lens 4, a beam splitter 5, a reference arm, a sample arm, a relay lens 6, and a customized imaging spectrometer 7. The reference arm includes an achromatic double glued difference lens 8 and a reference mirror 9; the sample arm includes an objective lens 10, a sample mirror 11, and a z-axis lifting platform 12. The structures of the two arms are symmetrical, and the position of the reference mirror is fixed. The two arms of the specific system design can be asymmetrical, and the light spot on the reference mirror can also be a point light spot, which can be achieved by adding a cylindrical lens to the reference arm. Figure 2 The light source in may specifically be a broadband light source.

[0029] The interferometric AC signal generated in the wavenumber domain when there is only one reflector on the sample arm with the reference mirror fixed in position It can be written as: (1) in, is the spectral distribution function of the light source, and are the reflection coefficients of the reference mirror and the sample mirror respectively. The first three items are combined and simplified to , is the optical path difference between the two arms, It is a nonlinear term introduced by the dispersion mismatch between the two arms. The complex interference signal can be constructed through Hilbert transform and the instantaneous phase can be obtained. : (2) in, The actual phase difference , n is an integer. Due to the dispersion term existence, In order to eliminate the dispersion term in the phase linearization calibration process, the instantaneous phase of the interference signal at two different optical path difference positions is subtracted: (3) From this we can see that and There is a linear relationship, so: (4).

[0030] It can be understood that the instantaneous phase difference is obtained in the present application. , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , can determine the linear relationship between the instantaneous phase difference and the wave number through linear fitting, and then calibrate based on the linear relationship The corresponding wave number This method can make full use of the phase information contained in the interference fringes and establish a more rigorous calibration model. It can eliminate the interference of the dispersion term caused by the dispersion mismatch between the two arms (reference arm and sample arm) during the calibration process, and take into account the offset between the spectral channels of different sampling points, so as to achieve higher-precision line-field OCT spectral calibration results.

[0031] In addition, it is worth noting that the spectral calibration of the traditional line-field spectrum domain OCT system only assumes that the ideal point objects of different fields of view are located on the front focal plane of the imaging spectrometer, so the light source is directly placed in front of the slit of the imaging spectrometer for calibration. However, during the actual measurement, the slit position is not an ideal point object, but a primary image produced by the sample to be measured, which has aberrations, which will cause the system calibration results to deviate greatly from the actual situation. The spectral calibration process of the present application makes the focal line spots of different wavelengths on the image plane and the positions of the optical fiber exit ends conjugate in the horizontal direction, which passes through the reference arm to the image plane, taking into account the entire propagation process, and is more in line with the actual measurement process. At the same time, the general SD-OCT system changes the optical path difference of the two arms by adjusting the position of the reference mirror, while the system calibrated by the present application fixes the position of the reference mirror, and places the mechanical structure used to adjust the optical path difference of the two arms on the sample arm, so that the spectrum generated by the reference mirror in the imaging spectrometer remains unchanged. Such a setting makes the spectral calibration results stable, and light of the same wavelength will always interfere at a fixed position on the image plane without offset.

[0032] The following is an illustrative description of the spectral calibration method for a line-view spectral domain OCT system provided by the present application through several examples. The method includes: (1) calculating a curve of phase difference versus spatial position; (2) generating discrete spectral lines; (3) enhancing spectral line signals; (4) calculating the sub-pixel position and corresponding phase difference of the peak of each spectral line; (5) completing spectral calibration by estimating parameters a and b by least squares fitting; and (6) dispersion estimation.

[0033] (1) Calculate the curve of phase difference changing with spatial position: First, Figure 3 As shown, adjust the z-axis lifting platform so that the optical path difference is and The AC quantity of the interference signal is collected and calculated at the positions and The interference fringes on the image plane at different optical path difference positions are as follows: Figure 4 As shown, the complex signal (complex interference signal) is obtained by Hilbert transform, and the phase terms of each complex signal are unwrapped to obtain and , use the difference between the two to calculate . Figure 4 middle Represents the image field of view.

[0034] (2) Generate discrete spectral lines: block the sample arm and couple the light emitted by the calibration light source into the spatial light path (refer to Figure 5 , Figure 5 The light source in the image is specifically the calibration light source), and finally a two-dimensional discrete spectrum with precise position is generated on the detector surface by the fixed reference arm, such as Figure 6 As shown. The calibration light source must be highly stable and able to produce discrete and known wavelengths. It can be a laser or a spectrum lamp (xenon lamp, neon lamp, mercury lamp). To provide more fitting data, the spectral line signals generated by different light sources can be combined.

[0035] (3) Enhanced spectral line signal: To solve the problem of weak spectral signals of some calibration light sources, it is necessary to enhance the signal. For example, the integration time can be extended and multi-frame averaging noise reduction methods can be used to collect images containing spectral line signals and separate background noise. The enhanced spectral signal is obtained by subtracting the latter from the former. .

[0036] (4) Calculate the sub-pixel position and corresponding phase difference of the peak value of each spectral line: Based on the discrete spectral signal, Sub-pixel position of the peak of a spectral line To make an estimate, for example, the Energy Center of Gravity Method (ECCM) can be used: (5) Here, the value of n is set to 2. is the spectral intensity distribution corresponding to the calibration light source, For the The pixel index corresponding to the peak value of the spectral line. Interpolation, we get The position corresponds to .

[0037] Here, the sub-pixel position of the peak of the spectrum line is explained. The spectrum line data is usually collected in discrete pixels. The integer pixel index corresponding to the peak of the discrete spectrum line signal cannot represent the actual position of the spectrum line peak. The real peak position may be between these pixels. Therefore, it is necessary to estimate the sub-pixel position of the spectrum line peak.

[0038] (5) The least squares fitting estimates the parameters a and b to complete the spectrum calibration: Based on the prior information of the calibration light source, we know , Indicates The wavelength corresponding to the spectral line, thus obtaining the data point , perform straight line fitting to estimate the parameters and .Will Substitute into formula (4) to complete the calibration.

[0039] (6) Dispersion estimation; In order to evaluate the dispersion of the system, the calibration results can be used to or Perform a first-order fit and calculate the residual, which is the nonlinear term. Based on this nonlinear term, the dispersion compensation can be made to the system in software or hardware.

[0040] In addition, considering that the single-wavelength line spot is not an ideal vertical straight line on the image plane, there will be a certain degree of curvature, resulting in an offset between the spectra of different fields of view. Therefore, the above calibration operation needs to be performed on each field of view.

[0041] The spectral calibration device for the line-view spectral domain OCT system provided in the present application is described below. The spectral calibration device for the line-view spectral domain OCT system described below and the spectral calibration method for the line-view spectral domain OCT system described above can be referenced to each other.

[0042] Figure 7 is a schematic diagram of the structure of a spectral calibration device for a line-view spectral domain OCT system provided in an embodiment of the present application, such as Figure 7 As shown, the device includes: an instantaneous phase difference acquisition module 14, a discrete spectrum line generation module 15, a spectrum line peak sub-pixel position calculation module 16 and a calibration module 17. Among them: The instantaneous phase difference acquisition module 14 is used to obtain the first optical path difference by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference , and subtract the instantaneous phases of the interference signals corresponding to the two optical path differences to obtain the instantaneous phase difference , the first optical path difference and the second optical path difference are different, Represents the pixel index of the detector in the line-field spectral domain OCT system; The discrete spectral line generation module 15 is used to generate discrete spectral lines on the detector based on the calibration light source by blocking the sample arm in the line field spectral domain OCT system, and obtain the spectral intensity distribution corresponding to the calibration light source. ; The spectrum line peak sub-pixel position calculation module 16 is used to calculate the peak sub-pixel position based on the instantaneous phase difference. Spectral intensity distribution corresponding to the calibration light source , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , Indicates the number of the spectral line; Calibration module 17, used for wave numbers corresponding to each spectral line and instantaneous phase difference , through linear fitting, determine the linear relationship between instantaneous phase difference and wave number, and calibrate based on the linear relationship The corresponding wave number .

[0043] It can be understood that the detailed functional implementation of each of the above-mentioned units / modules can be found in the introduction of the aforementioned method embodiment, and will not be repeated here.

[0044] It should be understood that the above-mentioned device is used to execute the method in the above-mentioned embodiment. The implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above-mentioned method. The working process of the device can refer to the corresponding process in the above-mentioned method, which will not be repeated here.

[0045] Based on the method in the above embodiment, an embodiment of the present application provides an electronic device, Figure 8 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application, such as Figure 8As shown, the electronic device may include: a processor (Processor) 810, a communication interface (Communications Interface) 820, a memory (Memory) 830 and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call the logic instructions in the memory 830 to execute the method in the above embodiment.

[0046] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application.

[0047] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method in the above embodiment.

[0048] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the method in the above embodiment.

[0049] It is understandable that the processor in the embodiment of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0050] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0051] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions may be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0052] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0053] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A spectral calibration method for a line-view spectral domain OCT system, characterized in that: include: The first optical path difference is obtained by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference , and subtract the instantaneous phases of the interference signals corresponding to the two optical path differences to obtain the instantaneous phase difference , the first optical path difference and the second optical path difference are different, Represents the pixel index of the detector in the line-field spectral domain OCT system; Based on the calibration light source, by blocking the sample arm in the line field spectral domain OCT system, discrete spectral lines are generated on the detector, and the spectral intensity distribution corresponding to the calibration light source is obtained. ; Based on the instantaneous phase difference Spectral intensity distribution corresponding to the calibration light source , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , Indicates the number of the spectral line; Based on the wave number corresponding to each spectral line and instantaneous phase difference , through linear fitting, determine the linear relationship between instantaneous phase difference and wave number, and calibrate based on the linear relationship The corresponding wave number .

2. The spectral calibration method for a line-view spectral domain OCT system according to claim 1, characterized in that: The first optical path difference is obtained by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference ,include: The optical path difference is and The AC quantity of the interference signal is obtained at the position of and ; AC quantity based on interference signal and , the complex interference signal is obtained by Hilbert transform and , unpacking the phase term of the complex interference signal to obtain and .

3. The spectral calibration method for a line-view spectral domain OCT system according to claim 1, characterized in that: The sub-pixel position of the peak value of each spectral line is calculated ,include: Based on the spectral intensity distribution corresponding to the calibration light source , the sub-pixel position of the peak of each spectral line is determined by the energy center of gravity method ECCM .

4. The spectral calibration method for a line-view spectral domain OCT system according to claim 1, characterized in that: Calculating sub-pixel positions The corresponding instantaneous phase difference ,include: Sub-pixel position based on the peak of each spectral line , through Interpolate to determine sub-pixel position The corresponding instantaneous phase difference .

5. The spectral calibration method for a line-view spectral domain OCT system according to claim 1, characterized in that: The spectral intensity distribution corresponding to the calibration light source is obtained ,include: Based on the discrete spectral lines generated on the detector, the spectral intensity distribution corresponding to the calibration light source is determined by enhancing the spectral line signal. .

6. The spectral calibration method for a line-view spectral domain OCT system according to claim 1, characterized in that: Based on linear relationship calibration The corresponding wave number After that, it also includes: By the first optical path difference The corresponding interference signal instantaneous phase Perform a first-order fit to determine the nonlinear term introduced by the dispersion mismatch between the two arms; or, The corresponding interference signal instantaneous phase Perform a first-order fit to determine the nonlinear term introduced by the dispersion mismatch between the two arms; Based on the nonlinear term, dispersion compensation is performed on the line-view spectral domain OCT system.

7. The spectral calibration method for a line-view spectral domain OCT system according to claim 1, characterized in that: Also includes: Calibrate different field of view channels along the target direction The corresponding wave number , the target direction is perpendicular to the direction of spectrum expansion on the detector image plane.

8. A spectral calibration device for a line-view spectral domain OCT system, characterized in that: include: The instantaneous phase difference acquisition module is used to obtain the first optical path difference by adjusting the lifting platform at the sample mirror in the line field spectral domain OCT system. The corresponding interference signal instantaneous phase The instantaneous phase of the interference signal corresponding to the second optical path difference , and subtract the instantaneous phases of the interference signals corresponding to the two optical path differences to obtain the instantaneous phase difference , the first optical path difference and the second optical path difference are different, Represents the pixel index of the detector in the line-field spectral domain OCT system; The discrete spectral line generation module is used to generate discrete spectral lines on the detector based on the calibration light source by blocking the sample arm in the line field spectral domain OCT system, and obtain the spectral intensity distribution corresponding to the calibration light source. ; Spectral line peak sub-pixel position calculation module, used to calculate the peak position based on the instantaneous phase difference Spectral intensity distribution corresponding to the calibration light source , calculate the sub-pixel position of the peak of each spectral line and sub-pixel position The corresponding instantaneous phase difference , Indicates the number of the spectral line; Calibration module, used to calculate the wave number corresponding to each spectral line and instantaneous phase difference , through linear fitting, determine the linear relationship between instantaneous phase difference and wave number, and calibrate based on the linear relationship The corresponding wave number .

9. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program runs on a processor, the processor is caused to execute the method according to any one of claims 1 to 7.

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