CN114847869B - Dual-band imaging system and method of large-field visible light OCT - Google Patents
Dual-band imaging system and method of large-field visible light OCT Download PDFInfo
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Abstract
The invention discloses a dual-band imaging system and a method of large-view-field visible light OCT, comprising the following steps: the light beam is incident on the detection sample through the sample arm and is reflected, interference is generated between the light beam and the light beam reflected in the reference arm, and the interference light beam is incident into the spectrometer; in the spectrometer, the interference light beams are split after passing through the second collimator and the grating in sequence, the split interference light beams are focused by the third focusing lens, part of interference light beams are reflected to the first CCD array by the reflecting mirror, and the rest interference light beams are incident to the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference light beams with different wave bands. The invention solves the problem that the imaging range is difficult to align due to the small detection depth of the visible light OCT during the large-view-field scanning detection.
Description
Technical Field
The invention relates to the technical field of optical coherence tomography, in particular to a dual-band imaging system and method of large-field visible light OCT.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
Optical coherence tomography (opticalcoherencetomography, OCT for short) is a new medical imaging method proposed in nineties of the last century, and has the advantages of higher resolution and stronger chromatographic capacity, non-contact, non-invasive, no damage and the like. The OCT technology is widely applied in the field of ophthalmic diagnosis, can be used for fundus imaging, retina cross-section imaging and the like, and has important roles and significance for early diagnosis and clinical diagnosis of ophthalmic diseases such as glaucoma, diabetic retinopathy and the like.
The visible light OCT technology uses a light source in the visible light band to perform scanning imaging, because the wavelength of the light wave in the visible light band is shorter and the frequency is higher, compared with the conventional OCT system using a near infrared light source, the OCT system has higher image resolution, but the increase of the frequency of the light source causes the reduction of the imaging depth. When large field scanning is performed, a small imaging depth causes the retina to go beyond an imaging range due to the curvature of the eyeball, and the retina goes beyond the imaging range causes a problem of alignment difficulty.
Disclosure of Invention
In order to solve the problems, the invention provides a dual-band imaging system and a dual-band imaging method for large-field visible light OCT, which simultaneously acquire a large-depth image and a high-resolution image and solve the problem that the imaging range is difficult to align due to the small detection depth of the visible light OCT during large-field scanning detection.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
in a first aspect, the present invention provides a dual-band imaging system for large field of view visible OCT, comprising: the device comprises a light-emitting device, a sample arm, a reference arm and a spectrometer;
The light-emitting device is used for generating a light beam and incident into the sample arm and the reference arm;
The sample arm comprises a first collimator, a scanning galvanometer, a first focusing lens and a second focusing lens, and an incident light beam sequentially enters the first collimator, the scanning galvanometer, the first focusing lens and the second focusing lens to be detected on the sample and reflected; the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
The spectrometer comprises a second collimator, a grating, a first CCD array, a reflecting mirror, a second CCD array, a beam expander and a third focusing lens, wherein interference beams are sequentially split after passing through the second collimator and the grating, the split interference beams are focused by the third focusing lens, part of interference beams are reflected to the first CCD array by the reflecting mirror and the beam expander, and the rest interference beams are incident into the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference beams of different wave bands.
As an alternative embodiment, the light emitting device includes a light source and an optical coupler; the optical coupler is respectively connected with the sample arm, the reference arm and the spectrometer, the light source emits light beams in a continuous spectrum range, and the light beams enter the reference arm and the sample arm after passing through the optical coupler; and the light beam reflected in the reference arm and the light beam reflected in the sample arm pass through the optical coupler, interfere in the optical coupler, and then the interference light beam is incident into the spectrometer.
As an alternative embodiment, the light emitting device includes a light source, a fourth collimator, a light splitting element, a fifth collimator, and a sixth collimator; the light source is connected with the input end of the fourth collimator, the output end of the fourth collimator is arranged opposite to the input end of the light splitting element, the plane mirror of the reference arm is arranged opposite to the reflection output end of the light splitting element, and the input end of the fifth collimator is arranged opposite to the transmission output end of the light splitting element; the output end of the fifth collimator is connected with the first collimator; the input end of the sixth collimator is opposite to the coherent output end of the light splitting element, and the output end of the sixth collimator is connected with the spectrometer.
As an alternative implementation manner, the incident light beam is converted into a parallel light beam after being collimated by the first collimator, the parallel light beam is incident into the scanning galvanometer, the parallel light beam is reflected into the 4f system after being scanned by the scanning galvanometer, and the parallel light beam is incident onto the detection sample after being refracted by the 4f system.
As an alternative embodiment, the 4f system comprises a first focusing lens and a second focusing lens; the parallel light beam passes through the object focal point of the first focusing lens, is focused on the image focal plane of the first focusing lens after refraction, the image focal plane of the first focusing lens is overlapped with the object focal plane of the second focusing lens, and is incident on the detection sample through the image focal point of the second focusing lens after passing through the object focal plane of the second focusing lens.
As an alternative embodiment, the relative positions of the first collimator, the scanning galvanometer and the 4f system are adjusted by the focal lengths of the first focusing lens and the second focusing lens.
As an alternative implementation manner, the reflection mirror is used for splitting the light beams with different wave bands, including that when the third focusing lens refracts the interference light beams, a part of interference light beams with longer wave bands are reflected into the first CCD array through the reflection mirror, and the rest interference light beams are directly incident into the second CCD array.
Alternatively, the wavelength band of the interference beam reflected into the first CCD array is larger than the wavelength band of the interference beam incident into the second CCD array, and the spectral width of the interference beam reflected into the first CCD array is smaller than the spectral width of the interference beam in the second CCD array.
As an alternative embodiment, the large depth imaging is performed based on the characteristic that the spectral resolution of the interference beam reflected into the first CCD array is high; high resolution imaging is performed based on the characteristic of the large spectral width of the interference beam incident into the second CCD array.
As an alternative embodiment, a beam expander is provided between the mirror and the first CCD array for expanding the diameter of the interference beam reflected into the first CCD array, thereby increasing the spectral resolution.
In a second aspect, the present invention provides an imaging method of a dual-band imaging system using the large field-of-view visible OCT of the first aspect, comprising:
the incident light beam is incident on the detection sample after passing through the sample arm and is reflected, and the imaging position of the detection sample in the depth direction and the imaging range of high resolution are adjusted by adjusting the optical path of the reference arm;
the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
In the spectrometer, the interference light beams are split after passing through the second collimator and the grating in sequence, the split interference light beams are focused by the third focusing lens, part of interference light beams are reflected to the first CCD array by the reflecting mirror, and the rest interference light beams are incident to the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference light beams with different wave bands.
Compared with the prior art, the invention has the beneficial effects that:
The invention provides a dual-band imaging system and a method for large-field visible light OCT, which are used for simultaneously acquiring a large-depth image and a high-resolution image by reflecting light beams of different wave bands on a detection sample and respectively detecting spectral information of two different wave bands by utilizing a grating and two CCD arrays, so that the problem that the imaging range is difficult to align due to smaller detection depth of the visible light OCT during large-field scanning detection is solved.
The invention provides a dual-band imaging system and a method for large-view-field visible light OCT, which are characterized in that a first interference light beam in a long wave band is reflected by a reflecting mirror in a spectrometer, the cross section of the reflecting mirror is designed to be trapezoid, when the first interference light beam in the long wave band is reflected, the detection resolution of the first interference light beam can be improved, the detection of light in another wave band can not be blocked, and meanwhile, the spectral detection of the first interference light beam and the second interference light beam is carried out by the reflecting mirror, so that the utilization of a full-band light source is realized.
Additional aspects of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
Fig. 1 is a schematic diagram of a dual-band imaging system of a large field-of-view visible OCT according to embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of a dual-band imaging system for large field-of-view visible OCT provided in embodiment 2 of the present invention;
Fig. 3 is a schematic diagram of dual-band imaging provided in embodiments 1 and 2 of the present invention.
Detailed Description
The invention is further described below with reference to the drawings and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms also are intended to include the plural forms, and furthermore, it is to be understood that the terms "comprises" and "comprising" and any variations thereof are intended to cover non-exclusive inclusions, such as, for example, processes, methods, systems, products or devices that comprise a series of steps or units, are not necessarily limited to those steps or units that are expressly listed, but may include other steps or units that are not expressly listed or inherent to such processes, methods, products or devices.
Embodiments of the invention and features of the embodiments may be combined with each other without conflict.
Example 1
As shown in fig. 1, the present embodiment provides a dual-band imaging system of large-field visible light OCT, including: the device comprises a light emitting device, a sample arm, a reference arm, a spectrometer, a first image processing system and a second image processing system;
The light emitting device is used for generating a light beam and comprises a light source and an optical coupler; the optical coupler is respectively connected with the sample arm, the reference arm and the spectrometer, the light beam emitted by the light source enters the optical coupler, the light beam is in a continuous spectrum range, and the light beam enters the sample arm and the reference arm after passing through the optical coupler;
The sample arm comprises a first collimator, a scanning galvanometer, a first focusing lens and a second focusing lens, and an incident light beam sequentially enters the first collimator, the scanning galvanometer, the first focusing lens and the second focusing lens to be detected on the sample and reflected; the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
The spectrometer comprises a second collimator, a grating, a first CCD array, a reflecting mirror, a second CCD array, a beam expander and a third focusing lens, wherein interference beams are sequentially split after passing through the second collimator and the grating, the split interference beams are focused by the third focusing lens, part of interference beams are reflected to the first CCD array by the reflecting mirror, and the rest interference beams are incident into the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference beams of different wave bands.
In this embodiment, the reference arm includes a third collimator and a plane mirror, and after the light beam is incident on the reference arm, the light beam is collimated by the third collimator and then reflected into the optical coupler by the plane mirror; when scanning with a large field of view, due to the existence of curvature of an eyeball, when scanning different positions of retina, the alignment position of an imaging range needs to be adjusted in real time according to the scanning position, and because reference light reflected by a reference arm only interferes with scattered light of a sample arm with a specific optical path difference, the imaging position of OCT in the depth direction is adjusted by adjusting the optical path of the reference arm.
In this embodiment, in the sample arm, the light beam reflected back through the human eye sequentially passes through the second focusing lens, the first focusing lens, the scanning galvanometer and the first collimator to be incident into the optical coupler, and the light beam reflected or scattered back through the reference arm and the sample arm interferes at the optical coupler, and the optical coupler is connected with the second collimator of the spectrometer to be incident into the spectrometer.
Example 2
As shown in fig. 2, the present embodiment provides a dual-band imaging system of large-field visible light OCT, including: the device comprises a light emitting device, a sample arm, a reference arm, a spectrometer, a first image processing system and a second image processing system;
The light-emitting device is used for generating a light beam and comprises a light source, a fourth collimator, a light-splitting element, a fifth collimator and a sixth collimator; the light beam emitted by the light source is sequentially incident into the sample arm through the fourth collimator, the light splitting element and the fifth collimator, and is reflected into the reference arm through the light splitting element;
The sample arm comprises a first collimator, a scanning galvanometer, a first focusing lens and a second focusing lens, and an incident light beam sequentially enters the first collimator, the scanning galvanometer, the first focusing lens and the second focusing lens to be detected on the sample and reflected; the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
The spectrometer comprises a second collimator, a grating, a first CCD array, a reflecting mirror, a second CCD array, a beam expander and a third focusing lens, wherein interference beams are sequentially split after passing through the second collimator and the grating, the split interference beams are focused by the third focusing lens, part of interference beams are reflected to the first CCD array by the reflecting mirror, and the rest interference beams are incident into the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference beams of different wave bands.
In this embodiment, the light source is connected to an input end of a fourth collimator through an optical fiber, and an output end of the fourth collimator is opposite to an input end of a light splitting element (beam splitter or beam splitter), where the light splitting element (beam splitter or beam splitter) is configured to receive output light of the fourth collimator;
The plane mirror of the reference arm is opposite to the reflection output end of the beam splitting element (beam splitter or beam splitter), and the input end of the fifth collimator is opposite to the transmission output end of the beam splitting element (beam splitter or beam splitter); the output end of the fifth collimator is connected with the input end of the first collimator;
the input end of the sixth collimator is opposite to the coherent output end of the beam splitting element (beam splitter or beam splitter), and the output end of the sixth collimator is connected with the second collimator of the spectrometer.
When scanning with a large field of view, due to the existence of curvature of an eyeball, when scanning different positions of retina, the alignment position of an imaging range needs to be adjusted in real time according to the scanning position, and because reference light reflected by a reference arm only interferes with scattered light of a sample arm with a specific optical path difference, the imaging position of OCT in the depth direction is adjusted by adjusting the optical path of the reference arm.
The reference arm comprises a plane mirror, and the light beam is reflected by the plane mirror after entering the reference arm; in the sample arm, the light beam sequentially passes through the second focusing lens, the first focusing lens, the scanning galvanometer and the first collimator to be reflected, the reflected light beam is interfered with the light beam reflected by the reference arm after passing through the fifth collimator, and then the interfered light beam is incident into the spectrometer after passing through the sixth collimator.
The two-band imaging systems of the large-field visible OCT provided in the above embodiments 1 and 2 are different in interference of the light emitting device and the reflected light, and the remaining structural composition and principle are identical. Specifically, the sample arm comprises a first collimator, a scanning galvanometer and a 4f system; the incident light beam is converted into a parallel light beam after being collimated by a first collimator, the parallel light beam is incident into a scanning galvanometer, the parallel light beam is reflected into a 4f system after being scanned by the scanning galvanometer, and the parallel light beam is incident onto a detection sample after being refracted by the 4f system;
Specifically, the 4f system includes a first focusing lens and a second focusing lens; firstly, a parallel light beam passes through an object space focus of a first focusing lens, and is focused on an image space focus plane of the first focusing lens after being refracted by the first focusing lens;
Then, the image space focal plane of the first focusing lens is overlapped with the object space focal plane of the second focusing lens, so that the parallel light beams focused on the image space focal plane of the first focusing lens pass through the object space focal plane of the second focusing lens and then become parallel light beams passing through the image space focal point of the second focusing lens;
Finally, the parallel light beam is incident on the detection sample through the image side focus of the second focusing lens.
Taking fundus imaging as an example, the pupil of the human eye is located at the image side focal point of the second focusing lens, and then the parallel light beam passing through the image side focal point of the second focusing lens enters the human eye, and is focused on the retina by refraction of the lens of the human eye, so that fundus imaging is performed.
As an alternative embodiment, the relative positional relationship of the first collimator, the scanning galvanometer and the 4f system is related to the 4 focal lengths of the first focusing lens and the second focusing lens.
Alternatively, the scanning galvanometer uses an X-Y scanning galvanometer to scan the beam in both X and Y directions.
The scanning beam of the scanning galvanometer is changed into a parallel beam which always passes through the detection sample through the refraction of the 4f system, so that the range of the scanning beam is always within the range of the detection sample. Taking fundus imaging as an example, the scanning beam of the scanning galvanometer is changed into a parallel beam which always passes through the pupil of the human eye through refraction of a 4f system, so that the range of the scanning beam entering the eye is always within the range of the pupil of the human eye, and the parallel beam entering the eye is limited by the pupil of the human eye, so that the beam which irradiates beyond the range of the pupil cannot enter the eye.
In embodiments 1 and 2, the spectrometer includes: the device comprises a second collimator, a grating, a first CCD array, a reflecting mirror, a beam expander, a second CCD array and a third focusing lens;
the second collimator is connected with the optical coupler or the sixth collimator, the interference light beam is collimated by the second collimator and then enters the grating, the grating splits the incident interference light beam, and then the split light beam is focused on the second CCD array through the third focusing lens;
The light beam is transmitted at different angles, the interference light beams with the same wavelength are transmitted at the same angle, the light wavelengths of the interference light beams are continuously distributed from small to large after passing through the grating and the third focusing lens, namely, the light beams with different wavelengths are focused at different positions of the second CCD array, and the light beams with the maximum wavelength and the minimum wavelength are respectively positioned at two sides, so that the light beam splitting is realized, and the light intensity with different wavelengths can be detected.
The light beams with different wave bands are split through the reflecting mirror, namely when the third focusing lens refracts the interference light beams, one part of the first interference light beams with longer wave bands are reflected into the first CCD array through the reflecting mirror, and the other part of the second interference light beams are directly incident into the second CCD array, so that the light beams with different wave bands are split; and the wave band of the first interference light beam is larger than that of the second interference light beam, and the spectrum width of the first interference light beam is smaller than that of the second interference light beam.
Compared with the second CCD array, the first CCD array has narrower spectral range corresponding to the same pixel, so that the spectral resolution of the first CCD array is higher, and the imaging depth is larger; the spectrum width of the second CCD array is larger, so that the imaging resolution is higher; namely, carrying out large-depth imaging based on the characteristic of high spectral resolution of the first interference light beam; high resolution imaging is performed based on the characteristic of the spectral width of the second interference beam.
As an alternative embodiment, a beam expander is disposed between the mirror and the first CCD array, the beam expander including a concave lens and a fourth focusing lens for expanding the diameter of the first interference beam, thereby increasing the spectral resolution of the spectrometer;
Specifically, when the first interference light beam is reflected into the first CCD array by the reflecting mirror, since the spectral range of the reflected first interference light beam is small, a beam expander is added between the first CCD array and the reflecting mirror to increase the photosensitive area of the first CCD array, and the detected wave band of each CCD photosensitive element in the first CCD array is smaller, namely the detected resolution of the spectrum is higher, so that the imaging depth of OCT is increased; and the second interference beam is directly incident into the second CCD array, and the resolution is high due to its large spectral range, but the imaging depth is reduced.
Alternatively, the beam expander adopts a galilean beam expander or other beam expander with similar functions such as a kepler beam expander.
As an alternative implementation mode, the cross section of the reflecting mirror is trapezoid, when the first interference light beam with a long wave band is reflected, the detection resolution of the first interference light beam can be improved, the detection of light with another wave band can not be blocked, the light splitting detection of the first interference light beam and the second interference light beam is carried out through the reflecting mirror, and the utilization of the full-wave band light source is realized.
Alternatively, the grating is a transmission grating, the reticle density is 1800l/mm, the grating constant is d= 555.56nm, the beam diameter after being collimated by the second collimator is 1mm, the band range of the beam is 500nm-600nm, and the grating incidence angle is i=45°.
The grating equation is: d (sin i-sin θ) =mλ; where d is the grating constant, i is the angle of incidence, θ is the angle of diffraction, m is the line order, where m=1, λ is the wavelength of the incident light.
As calculated according to the grating equation, the diffraction angle is θ 1 = -11.12 ° when the light wavelength is 500nm, and θ 2 = -21.89 ° when the light wavelength is 600 nm.
The diameter of the third focusing lens is 30mm, the focal length is f=100 mm, the object space focal plane of the third focusing lens coincides with the surface of the grating, the focal point coincides with the center of the grating, and the beam distribution length at the image space focal plane of the third focusing lens can be calculated to be 18.85mm.
The spectrometer adopts a linear CCD array as a photosensitive element, the number of effective image sensing pixels of a first CCD array is 4500 pixels multiplied by 3 lines, the size of the image sensing pixels is 4.7 μm multiplied by 4.7 μm, the effective photosensitive area of the first CCD array is 21.15mm multiplied by 14.1 μm, and the parameters of a second CCD array are the same as those of the first CCD array.
The mirror is 3mm x 3mm in size, reflects a 10% band range of light beams to the first CCD array, and the remaining 90% of the light beams are detected by the second CCD array. The distance between the reflecting plane of the reflecting mirror and the central plane of the fourth focusing lens is 70mm, the diameter of the light beam reflected by the reflecting mirror is about 1.9mm, and the incident angle of the light beam refracted by the fourth focusing lens on the reflecting mirror is 30 degrees.
The light beam reflected by the reflecting mirror utilizes a Galileo beam expander, the focal length of a concave lens of the Galileo beam expander is 5mm, the focal length of a convex lens is 50mm, and the beam expanding ratio is 1:10, the beam diameter is enlarged by 10 times, and the enlarged beam diameter is about 19mm. The distance between the concave lens of the beam expander and the reflecting mirror is 25mm, after the beam expander passes through, the divergence angle of the light beam is changed to 1/10 of the original divergence angle, and the distance between the second CCD array and the central plane of the focusing lens of the beam expander is 50mm and is positioned on the focusing plane of the light beam.
Through the design, the spectral resolution of the first CCD array is 9 times that of the second CCD array finally, the detection signal is used for high-depth imaging, the spectral width detected by the second CCD array is 9 times that of the first CCD array, and the detection signal is used for high-resolution imaging.
It should be understood that the foregoing design is merely one implementation, and gives a practical solution, where elements, positions, parameters, etc. may be changed according to practical applications, and do not limit the present invention.
In the present embodiment 1 and embodiment 2, interference light beams of different wavelength bands are detected by the first CCD array and the second CCD array, respectively, and then processed by the corresponding first image processing system and second image processing system, respectively; the first CCD array is connected with the first image processing system, the second CCD array is connected with the second image processing system, the first image processing system performs large-depth imaging, the second image processing system performs high-resolution imaging, and a dual-band imaging schematic diagram is shown in fig. 3.
In this embodiment, during scanning imaging, the position of the retina is determined according to the large-depth image obtained by the first image processing system, so as to obtain the front-back position of the high-resolution imaging field of view relative to the retina, and then the optical path of the reference arm is adjusted, so that the imaging field of view of the high-resolution image is located on the retina.
The spectrometer provided by the embodiment utilizes one grating and two CCD arrays to measure the spectral information of two different wave bands, and simultaneously obtains a large-depth image (low resolution) and a high-resolution image (small depth), so that the problem that the imaging range is difficult to align due to the small detection depth of the visible light OCT during large-field scanning detection is solved.
In further embodiments, a dual-band imaging system based on the large field-of-view visible OCT of embodiments 1 and 2 is further provided, comprising:
the incident light beam is incident on the detection sample after passing through the sample arm and is reflected, and the imaging position of the detection sample in the depth direction and the imaging range of high resolution are adjusted by adjusting the optical path of the reference arm;
the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
In the spectrometer, the interference light beams are split after passing through the second collimator and the grating in sequence, the split interference light beams are focused by the third focusing lens, part of interference light beams are reflected to the first CCD array by the reflecting mirror, and the rest interference light beams are incident to the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference light beams with different wave bands.
While the foregoing description of the embodiments of the present invention has been presented in conjunction with the drawings, it should be understood that it is not intended to limit the scope of the invention, but rather, it is intended to cover all modifications or variations within the scope of the invention as defined by the claims of the present invention.
Claims (9)
1. A dual-band imaging system for large field of view visible OCT comprising: the device comprises a light-emitting device, a sample arm, a reference arm and a spectrometer;
The light-emitting device is used for generating a light beam and incident into the sample arm and the reference arm;
The sample arm comprises a first collimator, a scanning galvanometer, a first focusing lens and a second focusing lens, and an incident light beam sequentially enters the first collimator, the scanning galvanometer, the first focusing lens and the second focusing lens to be detected on the sample and reflected; the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
The spectrometer comprises a second collimator, a grating, a first CCD array, a reflecting mirror, a second CCD array, a beam expander and a third focusing lens, wherein interference beams are sequentially split after passing through the second collimator and the grating, the split interference beams are focused by the third focusing lens, part of interference beams are reflected into the first CCD array by the reflecting mirror and the beam expander, and the rest interference beams are incident into the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference beams of different wave bands;
the wave band of the interference light beam reflected into the first CCD array is larger than that of the interference light beam incident into the second CCD array, and the large-depth imaging is performed based on the characteristic that the spectrum resolution of the interference light beam reflected into the first CCD array is high;
The spectral width of the interference light beam reflected into the first CCD array is smaller than that of the interference light beam in the second CCD array, and high-resolution imaging is performed based on the characteristic that the spectral width of the interference light beam incident into the second CCD array is large.
2. The dual band imaging system of large field of view visible OCT of claim 1, wherein said light emitting means comprises a light source and an optical coupler; the optical coupler is respectively connected with the sample arm, the reference arm and the spectrometer, the light source emits light beams in a continuous spectrum range, and the light beams enter the reference arm and the sample arm after passing through the optical coupler; and the light beam reflected in the reference arm and the light beam reflected in the sample arm pass through the optical coupler, interfere in the optical coupler, and then the interference light beam is incident into the spectrometer.
3. The dual band imaging system of large field of view visible OCT of claim 1, wherein said light emitting means comprises a light source, a fourth collimator, a light splitting element, a fifth collimator, and a sixth collimator; the light source is connected with the input end of the fourth collimator, the output end of the fourth collimator is arranged opposite to the input end of the light splitting element, the plane mirror of the reference arm is arranged opposite to the reflection output end of the light splitting element, and the input end of the fifth collimator is arranged opposite to the transmission output end of the light splitting element; the output end of the fifth collimator is connected with the first collimator; the input end of the sixth collimator is opposite to the coherent output end of the light splitting element, and the output end of the sixth collimator is connected with the spectrometer.
4. The dual-band imaging system of claim 1, wherein the incident beam is collimated by the first collimator and converted into a parallel beam, the parallel beam is incident into the scanning galvanometer, the parallel beam is reflected into the 4f system after being scanned by the scanning galvanometer, and the parallel beam is refracted by the 4f system and is incident onto the detection sample.
5. The dual band imaging system of large field of view visible OCT of claim 4, wherein said 4f system comprises a first focusing lens and a second focusing lens; the parallel light beam passes through the object focal point of the first focusing lens, is focused on the image focal plane of the first focusing lens after refraction, the image focal plane of the first focusing lens is overlapped with the object focal plane of the second focusing lens, and is incident on the detection sample through the image focal point of the second focusing lens after passing through the object focal plane of the second focusing lens.
6. The dual band imaging system of wide field visible OCT of claim 5, wherein the relative positions of the first collimator, the scanning galvanometer, and the 4f system are adjusted by the focal lengths of the first focusing lens and the second focusing lens.
7. The dual band imaging system of wide field visible OCT of claim 1, wherein splitting the different band beams by the mirror comprises reflecting a portion of the longer band interference beam by the mirror into the first CCD array and the remaining interference beam directly into the second CCD array when the third focusing lens refracts the interference beam.
8. A dual band imaging system for large field of view visible OCT according to claim 1, wherein a beam expander is provided between the mirror and the first CCD array for expanding the diameter of the interference beam reflected into the first CCD array, thereby increasing the spectral resolution.
9. An imaging method of a dual band imaging system utilizing the large field of view visible OCT of any one of claims 1-8, comprising:
the incident light beam is incident on the detection sample after passing through the sample arm and is reflected, and the imaging position of the detection sample in the depth direction and the imaging range of high resolution are adjusted by adjusting the optical path of the reference arm;
the reference arm reflects the incident light beam and then interferes with the light beam reflected by the sample arm, and the interference light beam generated by the interference light beam is incident into the spectrometer;
In the spectrometer, the interference light beams are split after passing through the second collimator and the grating in sequence, the split interference light beams are focused by the third focusing lens, part of interference light beams are reflected to the first CCD array by the reflecting mirror, and the rest interference light beams are incident to the second CCD array, so that high-depth imaging and high-resolution imaging are respectively carried out according to interference light beams with different wave bands.
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