CN114081444A - OCT imaging system and method based on integral transformation principle - Google Patents

OCT imaging system and method based on integral transformation principle Download PDF

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CN114081444A
CN114081444A CN202111345299.0A CN202111345299A CN114081444A CN 114081444 A CN114081444 A CN 114081444A CN 202111345299 A CN202111345299 A CN 202111345299A CN 114081444 A CN114081444 A CN 114081444A
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张晓�
周茜
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Abstract

The invention provides an integral transformation principle-based OCT imaging system and method, on the basis of a traditional OCT system, a modulator is firstly used for modulating a light beam in a sample arm to obtain specific illumination distribution which can be one-dimensional illumination or two-dimensional illumination, an illumination pattern is projected on a sample through a lens group, return light of different depths of the sample and reference return light enter an interferometer to interfere, and after the return light and the reference return light are detected by a detection device and collected by a collection module, data processing is completed by a computer and a two-dimensional or three-dimensional structural image of the sample is displayed. Compared with the traditional single-point measurement method of OCT, the method is based on the integral transformation principle, does not need to use devices such as a galvanometer and the like to scan a sample, has a simple system structure, allows higher sample optical power to be used, obviously improves the signal-to-noise ratio of OCT imaging, and can realize high-quality imaging of the sample under the condition of undersampling.

Description

OCT imaging system and method based on integral transformation principle
Technical Field
The invention belongs to the field of biomedical optical imaging, and particularly relates to an OCT imaging system and method based on an integral transformation principle.
Background
Optical Coherence Tomography (OCT) is a high-resolution biomedical imaging means which was originally introduced in the 90 s of the 20 th century, and is a micrometer-scale living tissue high-resolution tomographic imaging means which utilizes the principle of Coherence of scattered light of biological tissues to image. In an OCT system, light from a light source is split into two beams, one beam entering a reference arm and one beam entering a sample arm. The reference light and the return light of different depths of the sample arm interfere to form an interference spectrum, and finally, the computer is used for processing spectral data to analyze a tomographic image with tissue structure information, so that the non-invasive detection of the internal physiological structure of the sample is realized.
With the development of OCT technology, Time Domain OCT (TD-OCT) and frequency Domain OCT (Fourier Domain OCT) have been developed, but since Time Domain OCT has to introduce an optical path scanning device in a reference arm to limit its imaging speed, it is gradually replaced by frequency Domain OCT with a faster imaging speed. Currently, frequency domain OCT includes two major types: spectral Domain OCT (SD-OCT) and Swept-frequency OCT (Swept Source OCT, SS-OCT). The SD-OCT mainly uses a broadband light source and a line-scan camera to obtain an interference spectrum from an interferometer, and the SS-OCT uses a sweep light source capable of instantly outputting variable extremely narrow wavelengths and a balanced detector to perform scanning measurement on the interference spectrum. The sample arms of the two are essentially based on space point-by-point measurement, namely on the sample arm, the depth information of only one point on the sample can be detected each time, and meanwhile, the two-dimensional and three-dimensional structures of the sample are obtained by introducing beam deflection to scan by using a galvanometer. Therefore, the conventional frequency-domain OCT based on spatial single-point measurement requires not only many measurements to obtain two-dimensional and three-dimensional images of a sample. And is limited by the optical power damage threshold of the biological sample, it is impossible to concentrate excessive light energy to one point of the sample, so the imaging quality is restricted, and the signal-to-noise ratio of the image is low.
Disclosure of Invention
In view of the above, in order to overcome the above problems, the present invention provides an OCT imaging system and method based on the integral transformation principle, which achieve high-efficiency and high-quality imaging of a sample to be measured.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the invention discloses an OCT imaging system based on an integral transformation principle, which comprises a light source unit, an interferometer, a detection device, an acquisition module and a computer; the light source unit is used for emitting light for irradiating a sample to be detected to a sample arm and a reference arm of the interferometer; the detection device is used for detecting interference signals output by the interferometer and converting the interference signals into electric signals; the acquisition module is used for acquiring the electric signal output by the detection device and converting the electric signal into a digital signal; the computer is used for receiving and processing the digital signal to obtain a structural image of the sample, the sample arm comprises a modulator, the modulator modulates the light beam into a kernel function of integral transformation to generate an illumination pattern, the illumination pattern is projected to the sample to be detected, and light reflected and scattered at different depths of the sample to be detected returns to the interferometer along the original path under the irradiation of the illumination pattern; and the computer performs an inverse process of integral transformation on the digital signal and performs inverse Fourier transformation in the depth direction of the sample to obtain a structural image of the sample.
Wherein the kernel function of the integral transformation is a kernel function of a one-dimensional integral transformation or a kernel function of a two-dimensional integral transformation.
When the kernel function of the integral transformation is the kernel function of the one-dimensional integral transformation, the illumination pattern is the one-dimensional illumination pattern, the sample arm further comprises a one-dimensional focusing device for generating a line focusing effect and converging parallel light beams in one direction to carry out line illumination, and the modulator only needs to modulate the light rays in the one illumination dimension; and when the kernel function of the integral transformation is the kernel function of the two-dimensional integral transformation, the illumination pattern is a two-dimensional illumination pattern, and the modulator is used for two-dimensionally modulating the parallel light beams of the sample arm.
Wherein, the double-cemented column lens is achromatic.
Wherein the sample arm further comprises a lens group for projecting the illumination pattern generated by the modulator onto the sample to be measured.
Wherein the light source unit uses a broadband light source or a swept-frequency light source; the interferometer adopts a space optical path or an optical fiber optical path; under the condition of adopting an optical fiber light path, when the optical fiber outputs parallel light, a collimator is used at the output end of the optical fiber; the detection device uses a spectrometer, a detector or a double balanced detector.
The invention also provides an OCT imaging method based on the integral transformation principle, which adopts the system to image and comprises the following steps:
after the system is started, the modulator modulates light according to the mathematical principle of integral transformation, and a specific light illumination distribution determined by an integral transformation kernel function is obtained at a sample;
after each modulation, a detection device of the OCT system measures corresponding OCT interference signals, the acquisition module acquires the signals and sends the signals to a computer for data recording;
and processing the recorded data of the plurality of groups by the computer, and reconstructing the structural information of the sample according to an inverse integral transformation algorithm and an OCT data processing method.
Wherein the integral transform is a wavelet transform, a fourier transform, or a rawski transform.
If the integral transformation kernel function has a plurality of numbers, the integral transformation kernel function is decomposed into a real part and an imaginary part; the measurements are performed separately at the sample arm for the real and imaginary parts, using the corresponding different light illumination distributions.
If the real part or the imaginary part of the integral transformation kernel function has a negative value, writing the real part or the imaginary part into the form of the difference between two non-negative functions, and then carrying out differential measurement by using the light illumination distribution determined by the two non-negative functions.
Advantageous effects
In the system of the present invention, a modulator is used to replace a galvanometer or equivalent scanning device and focusing lens device that are necessary in a conventional sample arm. The modulator modulates the light beam to generate a specific illumination pattern to be projected on the sample, and the projected illumination pattern covers the whole sample area to be imaged. Therefore, compared with the space single-point measurement based on the galvanometer and the focusing lens device, the method can image without scanning the sample to be measured, and the system structure is simpler and more stable; and the invention allows the use of higher sample optical power with the same sample optical power damage threshold. Therefore, the high illumination power obviously improves the system detection signal capability, and further improves the signal-to-noise ratio of coherent imaging. Meanwhile, due to the sparsity of the sample image in the integral transform domain, the measurement times can be effectively reduced, and high-quality imaging of the sample under the condition of under-sampling can be realized.
In the system, when the modulator is far away from the sample, the lens group can be added, and the illumination pattern generated by the modulator is projected to the surface of the sample to be measured through the lens group, so that the adaptability of the system is stronger.
In the case of one-dimensional pattern illumination, the sample arm includes a one-dimensional focusing device (e.g., an achromatic doublet) for minimizing chromatic aberration while producing a line focusing effect, as well as a modulator for modulating the light beam, and a lens group for projecting the illumination pattern generated by the modulator onto the sample.
Drawings
FIG. 1 is a schematic diagram of an optical coherence tomography system employing a Mach-Zehnder interferometer;
FIG. 2 is a schematic diagram of an optical coherence tomography system using a Michelson interferometer;
FIG. 3 is a schematic diagram of a sample arm of an optical coherence tomography system using one-dimensional illumination in embodiment 1 of the present invention;
fig. 4 is a schematic diagram of a sample arm of an optical coherence tomography system using two-dimensional illumination in embodiment 2 of the present invention.
Wherein, 1-light source unit, 2-interferometer, 3-sample arm, 4-reference arm, 5-detecting device, 6-collecting module and computer, 7-achromatic double-cemented column lens, 8-modulator, 9-lens group, 10-sample to be measured
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The invention provides an OCT imaging system based on the integral transformation principle, which has the following basic principles: on the basis of a traditional OCT system, a modulator is used in a sample arm to modulate a light beam by applying the principle of 'integral transformation' so as to obtain a specific illumination distribution pattern, wherein the illumination distribution pattern can be one-dimensional illumination or two-dimensional illumination; the illumination distribution pattern is projected on a sample to be detected, return light and reference light of the sample to be detected at different depths enter the interferometer to interfere under the irradiation of the illumination pattern, and then are detected by the detection device and collected by the collection module, and data processing is completed by the computer and a two-dimensional or three-dimensional structural image of the sample is displayed. Compared with the traditional single-point measurement method of OCT, the method is based on the integral transformation principle, does not need to use devices such as a galvanometer and the like to scan a sample, has a simple system structure, allows higher sample optical power to be used, obviously improves the signal-to-noise ratio of OCT imaging, and can realize high-quality imaging of the sample under the condition of undersampling.
The system comprises a light source unit, an interferometer, a sample arm, a reference arm, a detection device, an acquisition module and a computer.
The light source unit is used for emitting light for irradiating a sample to be detected, and can be a broadband light source or a sweep frequency light source, and the working wavelength band of the light source unit can adopt one of 850nm, 1064nm, 1310nm and 1550nm or other imaging wavelength bands;
the interferometer is used for interfering the return light of the two arms to perform interference measurement, can be a Mach-Zehnder interferometer or a Michelson interferometer, adopts a space optical path or an optical fiber optical path, and can use a collimator at the output end of the optical fiber when the optical fiber needs to output parallel light under the condition of adopting the optical fiber optical path.
The sample arm is used for projecting a required illumination pattern to the sample, and light reaching the surface and the interior of the sample is reflected or scattered to return to the interferometer along the original path of the sample arm; in the case of one-dimensional pattern illumination, the sample arm includes a one-dimensional focusing device (e.g., an achromatic doublet lens for minimizing chromatic aberration while producing a line focusing effect), as well as a modulator for modulating the light beam, and a lens assembly for projecting the illumination pattern produced by the modulator onto the sample. In the case of two-dimensional pattern illumination, the one-dimensional focusing device is omitted as the case may be. In the case where the modulator is very close to the sample, the lens group may also be omitted. The specific illumination distribution obtained by modulating the light beam by the modulator in the sample arm comprises one-dimensional illumination and two-dimensional illumination.
The reference arm is used for providing delayed reference light and the sample arm returning light to interfere in the interferometer;
the detection device is used for detecting interference signals formed by superposition of light beams returned from the two arms and can be a spectrometer, a detector or a double-balanced detector;
the acquisition module is used for acquiring signals, and converting the electric signals into digital signals after analog-to-digital conversion;
the computer is used for receiving and processing the data and displaying the structural image of the sample.
The working steps are as follows: a light beam generated by the light source unit enters the interferometer and is divided into two beams, wherein one beam enters the reference arm and the other beam enters the sample arm; the modulator in the sample arm modulates the light beam to obtain the required light illumination distribution, and then the illumination pattern is projected to the sample to be measured through the lens group to obtain the return light of the sample at different depths; returning light of the reference arm and returning light at different depths of the sample enter the interferometer to interfere to form an interference signal; the interference signal enters the detection device to be detected, is collected by the collection module and converted into a digital signal, and is transmitted to the computer for data processing and displaying the structural image of the sample.
The system is suitable for TD-OCT, SD-OCT and SS-OCT, wherein the TD-OCT uses a broadband light source and a balanced detector, the SD-OCT uses the broadband light source and a spectrometer, and the SS-OCT uses a swept source and a balanced detector.
Example 1:
embodiment 1 of the present invention is a system using one-dimensional illumination, and a schematic view of a sample arm structure is shown in fig. 3. The optical path of the system adopting one-dimensional illumination and based on the integral transformation principle for optical coherence tomography can be in two modes according to the difference of interferometers: fig. 1 shows a system optical path diagram of optical coherence tomography using a Mach-Zehnder interferometer, and fig. 2 shows a system optical path diagram of optical coherence tomography using a Michelson interferometer. The system structure of embodiment 1 of the present invention includes: the device comprises a light source unit 1, an interferometer 2, a sample arm 3, a reference arm 4, a detection device 5, an acquisition module, a computer 6, an achromatic double-cemented-cylinder lens 7, a modulator 8, a lens group 9 and a sample to be measured 10.
The light source unit 1 is used for generating a light beam for irradiating a sample to be measured, and may be a broadband light source or a swept-frequency light source. The interferometer 2 is used for acquiring reflected and scattered light of the sample arm and delayed light of the reference arm to realize interference measurement on the sample. The sample arm 3 is used to project a one-dimensional illumination pattern onto the sample surface and collect the return light from the sample surface and inside. The reference arm 4 is used to provide reference light and to interfere with the sample arm return light in the interferometer. The detection device 5 is used for detecting interference signals formed by superposition of light beams returned from the two arms, and a spectrometer or a double balanced detector can be used. The acquisition module 6 is used for acquiring signals, namely converting analog signals into digital signals; the computer 6 is used for receiving and processing data and displaying a structural image of the sample.
Further, in the sample arm, an achromatic doublet 7 is used to reduce chromatic aberration to the maximum extent while generating a line focusing effect to converge parallel light beams in one direction for line illumination. The modulator 8 is used for modulating the light beam of the line illumination to obtain a required one-dimensional pattern to modulate the illumination light. The lens assembly 9 is used to project the one-dimensional illumination pattern produced by the modulator onto the sample surface.
When the system of the invention adopts one-dimensional illumination, a sample arm as shown in figure 3 is selected, and the corresponding imaging method comprises the following steps:
1) a light beam emitted by a light source 1 enters an interferometer 2 and is divided into two beams, wherein one beam enters a sample arm 3 and the other beam enters a reference arm 4;
2) parallel light beams entering the sample arm 3 are converged into a line after passing through an achromatic double-cemented cylindrical lens 7 and then irradiate the line on a modulator 8, the modulator 8 modulates the light into a one-dimensional integral transformation kernel function to generate a one-dimensional illumination pattern, the one-dimensional illumination pattern is projected to a sample to be measured 10 through a lens group 9, and light reflected or scattered at different depths of the sample under the irradiation of the illumination pattern returns to the interferometer 2 along the original path;
3) the reference arm 4 changes the reference light into reference return light returning to the interferometer 2;
4) the reflected and scattered light of the sample 10 and the reference return light are subjected to interference superposition in the interferometer 2 to form an interference signal;
5) the interference signal enters the detection device 5 for detection, is collected by the collection module 6 and is converted into a digital signal, and then is transmitted to the computer 6 for data processing, and the computer 6 displays the two-dimensional structural image of the sample 10.
According to the principle of integral transformation, the definition formula of one-dimensional integral transformation is as follows:
Figure BDA0003353836630000081
wherein, K (x, u) is a kernel function of integral transformation, and when a series of different u values are taken, the integral transformation kernel is expressed as a series of one-dimensional space distribution functions. These one-dimensional spatial distribution functions determine the one-dimensional illumination pattern produced by the modulator. The x direction is the direction of one-dimensional illumination, [ a, b ] is the illumination range of one-dimensional illumination pattern on the sample to be measured, u is the coordinate on the transform domain, f (x) represents the function to be transformed, g (u) represents the transformed function. I [ ] represents the integral transform.
The expression of the inverse of the integral transform is:
Figure BDA0003353836630000082
wherein I-1[]Which represents the inverse of the integral transform,
Figure BDA0003353836630000083
this is the kernel function of the inverse process.
Further, in step 4, several sets of interference signals output by the interferometer are measured corresponding to the illumination patterns determined by different u values, and a series of interference signals related to the u values are obtained, which are expressed as:
Figure BDA0003353836630000091
where R (x, K) is the interference spectrum of the sample arm return light and the reference arm return light at x, K is the wavenumber, and K (x, u) is the one-dimensional illumination pattern produced by the modulator determined by the value of u.
In step 5, the computer completes data processing and samplesAnd reconstructing the product to obtain a two-dimensional structural image of the sample, wherein the process is represented as:
Figure BDA0003353836630000092
or
Figure BDA0003353836630000093
Wherein, F-1Representing the inverse Fourier transform in the depth direction (i.e. z direction) of the sample,
Figure BDA0003353836630000094
is a two-dimensional structural image of the sample.
Example 2:
embodiment 1 of the present invention is a system when two-dimensional illumination is employed, and a schematic view of a sample arm structure is shown in fig. 4. The optical path of the system adopting two-dimensional illumination is the same as that of the system adopting one-dimensional illumination, namely, two modes also exist according to the difference of the selected interferometer: fig. 1 shows a system optical path diagram of optical coherence tomography using a Mach-Zehnder interferometer, and fig. 2 shows a system optical path diagram of optical coherence tomography using a Michelson interferometer. Wherein, when two-dimensional illumination is adopted, the system adopts the structural scheme as shown in figure 4. Therefore, the structure of the optical coherence tomography based on the integral transformation principle using the two-dimensional illumination includes: the system comprises a light source unit 1, an interferometer 2, a sample arm 3, a reference arm 4, a detection device 5, a collection module, a computer 6, a modulator 8, a lens group 9 and a sample to be measured 10.
The light source unit 1 is used for generating a light beam for irradiating a sample to be measured, and may be a broadband light source or a swept-frequency light source. The interferometer 2 is used for acquiring reflected and scattered light of the sample arm and delayed light of the reference arm to realize interference measurement on the sample. The sample arm 3 is used to project a two-dimensional illumination pattern onto the sample surface and to collect the return light from the sample surface and from the interior. The reference arm 4 is used to provide reference light and to interfere with the sample arm return light in the interferometer. The detecting device 5 is used for detecting an interference signal formed by superposition of light beams returned from the two arms, and can be a spectrometer or a double balanced detector. The acquisition module 6 is used for acquiring signals, namely converting analog signals into digital signals; the computer 6 is used for receiving and processing data and displaying a structural image of the sample.
Further, in the sample arm, a modulator 8 is used to modulate the parallel beam to obtain the desired two-dimensional pattern to illuminate the sample. The lens assembly 9 is used to project the two-dimensional illumination pattern produced by the modulator onto the sample surface.
When the system of the invention adopts two-dimensional illumination, a sample arm as shown in figure 4 is selected, and the corresponding imaging method comprises the following steps:
1) a light beam emitted by a light source 1 enters an interferometer 2 and is divided into two beams, wherein one beam enters a sample arm 3 and the other beam enters a reference arm 4;
2) the parallel light beams entering the sample arm 3 irradiate onto the modulator 8, the modulator 8 modulates the light beams into a kernel function of two-dimensional integral transformation to generate a two-dimensional illumination pattern, the two-dimensional illumination pattern is projected to a sample 10 to be measured through the lens group 9, and light reflected and scattered at different depths of the sample under the irradiation of the illumination pattern returns to the interferometer 2 along the original path;
3) the reference arm 4 changes the reference light into reference return light returning to the interferometer 2;
4) the reflected and scattered light of the sample 10 and the reference return light are subjected to interference superposition in the interferometer 2 to form an interference signal;
5) the interference signal enters the detection device 5 for detection, is acquired by the acquisition module 6 and is converted into a digital signal, and then is transmitted to the computer 6 for data processing, and the computer 6 displays the three-dimensional structure image of the sample 10.
According to the principle of integral transformation, the definition formula of two-dimensional integral transformation is:
Figure BDA0003353836630000101
wherein, K (x, y, u)x,uy) Taking a series of different (u) s for the kernel function of the integral transformx,uy) In value, the kernel function of the integral transform appears as a series of two-dimensional spatial distribution functions. These two-dimensional spatial distribution functions determine the two-dimensional illumination pattern produced by the modulator. x, y being two-dimensional illuminationThe horizontal and vertical coordinates of (a), (b), (c), (d) and (d)x,uy) For coordinates on the transform domain, f (x, y) represents the function to be transformed, g (u)x,uy) Representing the transformed function. I is2D[]Representing an integral transformation.
The expression of the inverse process based on the two-dimensional integral transformation principle is as follows:
Figure BDA0003353836630000111
wherein I2D -1[]Which represents the inverse of the integral transform,
Figure BDA0003353836630000112
this is the kernel function of the inverse process.
Further, in step 4, in the difference (u)x,uy) At a value corresponding to a difference (u)x,uy) Measuring the illumination pattern determined by the value, measuring several groups of interference signals output by the interferometer, and obtaining a series of AND (u)x,uy) A value-dependent interference signal, represented as:
Figure BDA0003353836630000113
wherein R (x, y, K) is an interference signal of the sample arm return light and the reference arm return light at (x, y), K is a wave number, and K (x, y, u)x,uy) Is (u)x,uy) The value of the two-dimensional illumination pattern that the modulator needs to produce is determined.
In step 5, the computer completes data processing, and reconstructs the sample to obtain a three-dimensional structural image of the sample, and the process is represented as:
Figure BDA0003353836630000114
or
Figure BDA0003353836630000115
Wherein, F-1Representing the inverse Fourier transform in the depth direction (i.e. z direction) of the sample,
Figure BDA0003353836630000116
is a three-dimensional structural image of the sample.
In embodiments 1 and 2, the integral transformation may be implemented by the integral transformation commonly used in mathematics, such as: wavelet transform, fourier transform, lagrange transform, etc.
In embodiments 1 and 2, if there is a complex number in the integral transformation kernel, the integral transformation kernel can be decomposed into a real part and an imaginary part. The measurements are performed separately at the sample arm for the real and imaginary parts, using the corresponding different light illumination distributions.
In embodiments 1 and 2, if the real part or the imaginary part of the integral transformation kernel function has a negative value, the real part or the imaginary part can be written as the difference between two non-negative functions, and the light illumination distribution determined by the two non-negative functions is used for differential measurement.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. Any person skilled in the art can use the concept to make insubstantial changes from the invention within the technical scope of the invention disclosed, which falls into the act of infringing the scope of the invention.

Claims (10)

1. An OCT imaging system based on integral transformation principle comprises a light source unit, an interferometer, a detection device, an acquisition module and a computer; the light source unit is used for emitting light for irradiating a sample to be detected to a sample arm and a reference arm of the interferometer; the detection device is used for detecting interference signals output by the interferometer and converting the interference signals into electric signals; the acquisition module is used for acquiring the electric signal output by the detection device and converting the electric signal into a digital signal; the computer is used for receiving and processing the digital signal to obtain a structural image of the sample, and is characterized in that the sample arm comprises a modulator, the modulator modulates the light beam into a kernel function of integral transformation to generate an illumination pattern, the illumination pattern is projected to the sample to be detected, and light reflected and scattered at different depths of the sample to be detected returns to the interferometer along the original path under the irradiation of the illumination pattern; and the computer performs an inverse process of integral transformation on the digital signal and performs inverse Fourier transformation in the depth direction of the sample to obtain a structural image of the sample.
2. The system of claim 1, wherein the kernel function of the integral transform is a kernel function of a one-dimensional integral transform or a kernel function of a two-dimensional integral transform.
3. The system of claim 2, wherein when the kernel function of the integral transform is a kernel function of a one-dimensional integral transform, the illumination pattern is a one-dimensional illumination pattern, the sample arm further comprises a one-dimensional focusing device for generating a line focusing effect to converge parallel light beams in one direction for line illumination, the modulator only needs to modulate the light in the one illumination dimension; and when the kernel function of the integral transformation is the kernel function of the two-dimensional integral transformation, the illumination pattern is a two-dimensional illumination pattern, and the modulator is used for two-dimensionally modulating the parallel light beams of the sample arm.
4. The system of claim 3, wherein the lens is an achromatic doublet.
5. The system of any of claims 1-4, wherein the sample arm further comprises a lens group for projecting the illumination pattern generated by the modulator onto the sample under test.
6. The system of any one of claims 1-4, wherein the light source unit uses a broadband light source or a swept frequency light source; the interferometer adopts a space optical path or an optical fiber optical path; under the condition of adopting an optical fiber light path, when the optical fiber outputs parallel light, a collimator is used at the output end of the optical fiber; the detection device uses a spectrometer, a detector or a double balanced detector.
7. An OCT imaging method based on the principle of integral transformation, characterized in that imaging is carried out using a system according to any one of claims 1 to 4, comprising the following steps:
after the system is started, the modulator modulates light according to the mathematical principle of integral transformation, and a specific light illumination distribution determined by an integral transformation kernel function is obtained at a sample;
after each modulation, a detection device of the OCT system measures corresponding OCT interference signals, the acquisition module acquires the signals and sends the signals to a computer for data recording;
and processing the recorded data of the plurality of groups by the computer, and reconstructing the structural information of the sample according to an inverse integral transformation algorithm and an OCT data processing method.
8. The OCT imaging method of claim 7, wherein the integral transform is a wavelet transform, a fourier transform, or a raynaud transform.
9. The OCT imaging method according to claim 7 or 8, wherein the integral transform kernel decomposes an integral transform kernel into a real part and an imaginary part if a complex number exists; the measurements are performed separately at the sample arm for the real and imaginary parts, using the corresponding different light illumination distributions.
10. The OCT imaging method of claim 9, wherein if the real or imaginary part of the integral transform kernel has a negative value, the real or imaginary part is written as the difference between two non-negative functions, and the light illumination distribution determined by the two non-negative functions is used for differential measurement.
CN202111345299.0A 2021-11-15 2021-11-15 OCT imaging system and method based on integral transformation principle Pending CN114081444A (en)

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