Fundus multi-mode synchronous imaging system
Technical Field
The invention relates to an optical imaging and biomedical diagnosis device, in particular to a fundus multi-mode synchronous imaging system.
Background
At present, a plurality of fundus retinal imaging technologies exist clinically, including fundus cameras, optical coherence tomography, confocal scanning and the like, and play an important role in biological research and disease diagnosis.
The laser confocal scanning ophthalmoscope has been studied in a large number of ways of high-resolution imaging by filtering stray light through a conjugated aperture, and is successfully applied to biological research and medical diagnosis, including ophthalmic imaging, while the laser line confocal scanning technology changes the conjugated aperture into a conjugated slit on the basis of laser confocal scanning, which greatly improves the imaging speed although sacrificing part of the imaging resolution, and compared with a fundus camera exposed by strong light flicker, can realize high-speed real-time imaging of the fundus.
Patent application CN104224109A discloses a fundus camera combined with OCT system, combining the fundus camera with optical coherence tomography, but because the fundus camera uses scintillation exposure, strong light can generate great stimulation to the eye, and can not continuously image; patent application CN104684457A discloses two-dimensional confocal imaging using an OCT light source and scanning optics, taking part of the sample light of optical coherence tomography as the imaging light for confocal imaging, but laser confocal scanning imaging is transverse scanning and optical coherence tomography is longitudinal tomography, which is very slow in transverse direction and will greatly affect the speed of confocal imaging.
Disclosure of Invention
Therefore, there is a need for a fundus multi-modal synchronous imaging system, which combines the line scanning fast imaging technology and the optical coherence tomography technology to effectively utilize the optical coherence tomography technology and the line confocal scanning speed, so as to achieve the purpose of fast surface imaging and tomographic imaging of the retina of the eye fundus.
In order to achieve the purpose, the invention adopts the following technical scheme:
on one hand, the fundus multi-mode synchronous imaging system provided by the invention comprises an optical coherence tomography module, a slow axis scanning module, an imaging module, a hollow slit reflector, a line scanning confocal illumination module, a fast axis scanning module and an eye objective lens, wherein the optical coherence tomography module is used for forming optical coherence tomography sample light, the slow axis scanning module comprises a slow axis scanning galvanometer and a slow axis focusing lens, the imaging module comprises a focusing lens, a spectroscope and a detector, the line scanning confocal illumination module comprises a laser, a first collimator and a cylindrical lens, and the fast axis scanning module comprises a fast axis scanning galvanometer and a scanning lens; wherein:
the optical coherence tomography sample light is collimated by a collimator and then enters the slow axis scanning galvanometer, then enters the spectroscope after passing through the slow axis focusing lens, and the sample light reflected by the spectroscope penetrates through the slit of the hollow slit reflector after being focused by the focusing lens;
the laser beam emitted by the laser sequentially passes through the first collimator and the cylindrical lens and then enters the hollow slit reflector, and the laser beam is combined with the optical coherence tomography sample light penetrating through the slit of the hollow slit reflector after being reflected by the hollow slit reflector to form combined light;
the combined light passes through the fast axis scanning galvanometer, the scanning lens and the ocular objective lens and then synchronously illuminates and images the eye ground, the formed imaging light passes through the ocular objective lens, the scanning lens, the fast axis scanning galvanometer and the slit of the hollow slit reflector in sequence after being reflected by the retina of the eye ground, then passes through the focusing lens after being focused, the imaging light transmitted by the spectroscope is received and imaged by the detector, and then passes through the focusing lens after being focused, the imaging light reflected by the spectroscope passes through the slow axis focusing lens and the slow axis scanning galvanometer in sequence after being focused by the focusing lens, and the optical coherence tomography module interferes with the imaging.
In some preferred embodiments, the optical coherence tomography module is a swept-source optical coherence tomography unit or a spectral-domain optical coherence tomography unit.
In some preferred embodiments, the slow axis focusing lens in the slow axis scanning module and the focusing lens in the imaging module form a 4f system.
In some preferred embodiments, the slow axis scanning galvanometer and the fast axis scanning galvanometer are in conjugate positions.
In some preferred embodiments, the scanning track of the hollow slit mirror after the optical coherence tomography sample light is scanned by the slow axis scanning galvanometer is the same as the slit direction.
In some preferred embodiments, the beam splitter is a beam splitter plate, a beam splitter prism or a beam splitter film.
In some preferred embodiments, the hollow slit mirror is a glass sheet plated with a slit reflective film or a slit-cut mirror.
In some preferred embodiments, the non-converging direction of the cylindrical mirror is perpendicular to the slit direction of the hollow slit mirror, and the center of the fast axis scanning galvanometer is located at the focal point of the cylindrical mirror.
In some preferred embodiments, the hollow slit mirror is a glass sheet plated with a slit reflective film or a slit-cut mirror.
By adopting the technical scheme, the invention can realize the following beneficial effects:
in the fundus multi-mode synchronous imaging system provided by the invention, the optical coherence tomography sample light enters the slow axis scanning galvanometer after being collimated by the first collimator, then enters the spectroscope after passing through the slow axis focusing lens, and the sample light reflected by the spectroscope penetrates through the slit of the hollow slit reflector after being focused by the focusing lens; laser beams emitted by the laser sequentially pass through the collimator and the cylindrical mirror and then enter the hollow slit reflector, and are combined with sample light penetrating through a slit of the hollow slit reflector after being reflected by the hollow slit reflector to form combined light; the combined light passes through the fast axis scanning galvanometer, the scanning lens and the ocular objective lens and then synchronously illuminates and images the fundus, the formed imaging light passes through the ocular objective lens, the scanning lens, the fast axis scanning galvanometer and the slit of the hollow slit reflector in sequence after being reflected by the retina of the fundus, enters the focusing lens, is focused by the focusing lens and then passes through the imaging light transmitted by the spectroscope and is received and imaged by the detector, the imaging light which is focused by the focusing lens and then reflected by the spectroscope passes through the slow axis focusing lens and the slow axis scanning galvanometer in sequence to be interfered and imaged in the optical coherence tomography module, the fundus multi-mode synchronous imaging system provided by the invention effectively reduces system hardware by combining a line scanning fast imaging technology and an optical coherence tomography technology and adopting a common optical path resonance mirror synchronous scanning imaging method, and the hollow slit reflector is adopted to solve the problem that the scanning of optical coherence tomography is not influenced while the bright spots are reflected by the lens and the cornea, so that the effective utilization of the optical coherence tomography technology and the linear confocal scanning speed is realized, and the purposes of quick surface imaging and tomographic imaging of the fundus retina are achieved.
Drawings
Fig. 1 is a schematic structural diagram of a fundus multi-modality simultaneous imaging system according to this embodiment.
Fig. 2 is a schematic structural diagram of a fundus multi-modality simultaneous imaging system provided in embodiment 1 of the present invention.
Fig. 3 shows two typical hollow slit mirrors provided in embodiment 1 of the present invention.
Fig. 4 is a schematic diagram of the relationship between the slow-axis scanning beam trajectory and the slit according to embodiment 1 of the present invention.
Fig. 5 is a schematic structural diagram of a fundus multi-modality simultaneous imaging system provided in embodiment 2 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, a fundus multi-modality synchronous imaging system according to an embodiment of the present invention includes: the device comprises a line scanning confocal illumination module 1, a slow axis scanning module 2, an optical coherence tomography module 3, a fast axis scanning module 4, a hollow slit reflector 5, an imaging module 6, an ocular objective lens 7 and an eyeground retina 8. Wherein:
the optical coherence tomography module 3 is used to form optical coherence tomography sample light. The slow-axis scanning module 2 includes a slow-axis scanning galvanometer 21 and a slow-axis focusing lens 22. The imaging module 6 includes a focusing lens 61, a beam splitter 62 and a detector 63. The line scanning confocal illumination module 1 includes a laser 11, a first collimator 12, and a cylindrical lens 13. The fast axis scanning module 4 includes a fast axis scanning galvanometer 41 and a scanning lens 42.
The fundus multi-mode synchronous imaging system provided by the invention has the working mode as follows:
the sample light of the optical coherence tomography is collimated by a collimator and then enters the slow axis scanning galvanometer 21, then enters the spectroscope 62 after passing through the slow axis focusing lens 22, and the sample light reflected by the spectroscope 62 is focused by the focusing lens 61 and then penetrates through the slit of the hollow slit reflector 5;
the laser beam emitted by the laser 11 sequentially passes through the first collimator 12 and the cylindrical lens 13 and then enters the hollow slit reflector 5, and the laser beam is reflected by the hollow slit reflector 5 and then is combined with the sample light penetrating through the slit of the hollow slit reflector 5 to form combined light;
the combined light passes through the fast axis scanning galvanometer 41, the scanning lens 42 and the ocular objective lens 7 and then synchronously illuminates and images the fundus, the formed imaging light passes through the ocular objective lens 7, the scanning lens 42, the fast axis scanning galvanometer 41 and the slit of the hollow slit reflector 5 in sequence after being reflected by the fundus retina 8 and then enters the focusing lens 61, the imaging light passes through the spectroscope 62 after being focused by the focusing lens 61 and is received and imaged by the detector 63, and the imaging light passes through the spectroscope 62 after being focused by the focusing lens 61 and then passes through the slow axis focusing lens 22 and the slow axis scanning galvanometer 21 in sequence after being focused by the focusing lens 61 and then passes through the optical coherence tomography module 3 for interference imaging.
The fundus multi-mode synchronous imaging system provided by the invention can be understood by combining the line scanning rapid imaging technology and the optical coherence tomography imaging technology, adopting the common optical path resonance mirror synchronous scanning imaging method to effectively reduce system hardware, adopting the hollow slit reflector to solve the problem that the scanning of the optical coherence tomography is not influenced while the bright spots are reflected by the lens and the cornea, realizing the effective utilization of the optical coherence tomography technology and the line confocal scanning speed, and achieving the purposes of rapid surface imaging and tomography of the fundus retina.
Example 1
Fig. 2 is a schematic structural diagram of a fundus multi-modality simultaneous imaging system according to embodiment 1 of the present invention.
In this embodiment, the optical coherence tomography module 3 is a swept-source optical coherence tomography unit, and includes: a light source 311, a first coupler 312, a second collimator 313, a compensating mirror 316, a right-angle reflecting prism 317, a third collimator 315, a second coupler 318, and a balanced detector 319.
Specifically, light emitted by the light source 311 for optical coherence tomography is split into two light beams after passing through the first coupler 312, wherein one light beam is emitted through the collimator 314, passes through the compensating mirror 316 and the right-angle reflecting prism 317, is received by the collimator 316, and reaches the second coupler 318 as reference light; the other part of the light reaches the collimator 313 from the first coupler 312 as optical coherence tomography sample light, and is emitted from the collimator 313 and then enters the slow axis scanning galvanometer 21, and then enters the spectroscope 62 after passing through the slow axis focusing lens 22, and the sample light reflected by the spectroscope 62 is focused by the focusing lens 61 and then passes through the slit of the hollow slit reflector 5.
The laser beam emitted by the laser 11 sequentially passes through the first collimator 12 and the cylindrical lens 13 and then enters the hollow slit reflector 5, and the laser beam is reflected by the hollow slit reflector 5 and then is combined with the sample light penetrating through the slit of the hollow slit reflector 5 to form combined light;
the combined light passes through the fast axis scanning galvanometer 41, the scanning lens 42 and the ocular objective lens 7 and then synchronously illuminates and images the fundus, and the formed imaging light passes through the ocular objective lens 7, the scanning lens 42, the fast axis scanning galvanometer 41 and the slit of the hollow slit reflector 5 in sequence after being reflected by the fundus retina 8 and then enters the focusing lens 61, and then passes through the imaging light transmitted by the spectroscope 62 after being focused by the focusing lens 61 and is received and imaged by the detector 63.
It can be understood that the imaging light reflected by the beam splitter 62 after being focused by the focusing lens 61 passes through the slow-axis focusing lens 22 and the slow-axis scanning galvanometer 21 in sequence, is received by the collimator 313, and is coupled by the first coupler 312, wherein most of the light enters the second coupler 318, is interfered with the reference light for imaging, and is finally received and imaged by the balanced detector 319.
In some preferred embodiments, the swept source optical coherence tomography unit has a swept source model of santec-HSL-10, a sweep speed of 100kHz, and a center wavelength of 1060 nm. It can be understood that the model of the swept-frequency light source, the sweep-frequency speed, and the center wavelength of the swept-frequency source optical coherence tomography unit are not limited to the above settings, and can be adjusted in practice according to practical situations.
It can be understood that after the light emitted from the swept-source 311 passes through the first coupler 312 of the coupler 322, 80% of the light passes through the second collimator 313, the compensating mirror 316 and the right-angle reflecting prism 317 and is received by the third collimator 315 again, and another 20% of the light reaches the collimator 313 as the sample light.
In some preferred embodiments, the scanning speed of the fast axis scanning galvanometer is 200Hz, and the size of the mirror surface is 10mmX15 mm. It can be understood that, in practice, the scanning speed and the mirror size of the fast axis scanning galvanometer can be adjusted according to actual conditions.
The scanning speed set by the slow axis scanning galvanometer is 0.5Hz, the model is the same as that of the fast axis scanning galvanometer, and the scanning speed is Cambridge 6220H, and the scanning axes are vertical to each other. It can be understood that the model of the slow-axis scanning galvanometer is not limited to the model, and can be adjusted according to actual conditions in practice.
In some preferred embodiments, the slow-axis focusing lens 22 and the focusing lens 61 form a 4f system, and both the slow-axis scanning galvanometer and the fast-axis scanning galvanometer are located at the focal point of the lens of the 4f system.
In some preferred embodiments, the laser 11 of the line-scanning confocal illumination module 1 emits 650nm light, which passes through the collimator 142 and becomes a parallel light spot with a diameter of 20mm, and is condensed into a line beam by the cylindrical lens 13 with a focal length of 40mm, the light beam is condensed in a direction parallel to the slit direction, the light along the optical axis direction passes through the slit, and most of the non-optical axis light is reflected by the hollow slit reflector.
Referring to fig. 3, the hollow slit reflector 5 is a glass sheet coated with a slit reflective film (left side view) or a slit mirror (right side view), and preferably, the hollow slit reflector is a glass sheet coated with a slit reflective film.
Referring to fig. 4, after the sample light of the optical coherence tomography is scanned by the slow axis scanning galvanometer 21, the sample light passes through the slit of the hollow slit reflector 5, and the scanning direction is the same as the slit direction.
In some preferred embodiments, the beam splitter 62 is a beam splitter plate, a beam splitter prism, or a beam splitter film. Preferably, the beam splitter is a thorlabdmsp 805, short pass, cut to wavelength 805 nm.
In some preferred embodiments, the detector 63 is model E2V-EM4, 512pixels, maximum sampling rate 210 kHz.
The fundus multi-mode synchronous imaging system provided by the embodiment of the invention combines the line scanning rapid imaging technology and the optical coherence tomography imaging technology, adopts the synchronous scanning imaging method of the common optical path resonance mirror to effectively reduce system hardware, adopts the hollow slit reflector to solve the problem that the scanning of the optical coherence tomography is not influenced while the bright spots are reflected by the lens and the cornea, realizes the effective utilization of the optical coherence tomography technology and the line confocal scanning speed, and achieves the purposes of rapid surface imaging and tomography of the fundus retina.
Example 2
Fig. 5 is a schematic structural diagram of a fundus multi-modality simultaneous imaging system according to embodiment 2 of the present invention.
In the present embodiment, the optical coherence tomography module 3 is a spectral domain optical coherence tomography unit, and includes a semiconductor laser 321, a coupler 322, a collimator 328, a compensation mirror 325, a plane mirror 326, a collimator 327, a collimator 328, a grating 329, a focusing lens 330, and a line camera 331.
The light source of the spectral domain optical coherence tomography unit is a semiconductor laser 321 with the model of SLD-351, the central wavelength is 830nm, and the bandwidth is 80 nm.
It can be understood that, after the light emitted by the semiconductor laser 321 passes through the coupler 322, 80% of the light passes through the collimator 324, the compensating mirror 325, and is reflected by the plane mirror 326 and then received by the collimator 324 again; in addition, 20% of the light reaches the collimator 323 as sample light, and is emitted from the collimator 323 and then enters the slow-axis scanning galvanometer 21, and then enters the spectroscope 62 after passing through the slow-axis focusing lens 22, and the sample light reflected by the spectroscope 62 is focused by the focusing lens 61 and then passes through the slit of the hollow slit reflector 5.
The laser beam emitted by the laser 11 sequentially passes through the collimator 12 and the cylindrical lens 13 and then enters the hollow slit reflector 5, and the laser beam is reflected by the hollow slit reflector 5 and then combined with the sample light penetrating through the slit of the hollow slit reflector 5 to form combined light;
the combined light passes through the fast axis scanning galvanometer 41, the scanning lens 42 and the ocular objective lens 7 and then synchronously illuminates and images the fundus, and the formed imaging light passes through the ocular objective lens 7, the scanning lens 42, the fast axis scanning galvanometer 41 and the slit of the hollow slit reflector 5 in sequence after being reflected by the fundus retina 8 and then enters the focusing lens 61, and then passes through the imaging light transmitted by the spectroscope 62 after being focused by the focusing lens 61 and is received and imaged by the detector 63.
It can be understood that the imaging light reflected by the beam splitter 62 after being focused by the focusing lens 61 is sequentially received by the collimator 323 through the slow-axis focusing lens 22 and the slow-axis scanning galvanometer 21, enters the coupler 322 to generate interference imaging with the reference light, enters the collimator 327, is collimated into parallel beams by the collimator 328, is separated by the grating 329 from each spectrum, is focused by the focusing lens 330, and is finally received by the line camera 331.
The fundus multi-mode synchronous imaging system provided by the embodiment of the invention combines the line scanning rapid imaging technology and the optical coherence tomography imaging technology, adopts the synchronous scanning imaging method of the common optical path resonance mirror to effectively reduce system hardware, adopts the hollow slit reflector to solve the problem that the scanning of the optical coherence tomography is not influenced while the bright spots are reflected by the lens and the cornea, realizes the effective utilization of the optical coherence tomography technology and the line confocal scanning speed, and achieves the purposes of rapid surface imaging and tomography of the fundus retina.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.