Near-field and far-field tunable imaging device and method based on optical fiber

Abstract

This invention discloses a near-field and far-field tunable imaging device and method based on optical fiber, belonging to the field of fiber optic microscopic endoscopy imaging. The device includes a light source beam splitting component, a wavefront shaping component, an interferometry component, and a signal receiving component. The light source beam splitting component splits the laser beam into a reference beam (first beam) and a probe beam (second beam). The wavefront shaping component modulates the phase of the second beam to allow it to enter the multimode fiber bundle light source end. The interferometry component interferes the reference beam emitted from the single-mode fiber with the probe beam emitted from the multimode fiber bundle probe end at the first beam splitter and images it onto a camera. The signal receiving component receives the fluorescence signal or reflected laser signal from the sample. This invention is based on frequency domain modulation and utilizes a specially designed detection and collection module to achieve synchronous compatibility between near-field and far-field imaging.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic microscopic endoscopy imaging, specifically relating to a near-field and far-field adjustable imaging device and method based on optical fiber. Background Technology

[0002] The development of modern imaging technology has transcended the traditional simple correspondence between observed targets and imaging results. With the continuous advancement of theories such as wavefront shaping and computational optics, as well as the continuous improvement of related modulation device technologies, imaging methods and imaging ranges have been greatly expanded. For example, in the fields of depth imaging in biological samples and imaging through disordered and complex media, emerging multimode fiber imaging technology has demonstrated unique advantages.

[0003] Multimode fiber imaging technology can achieve extremely high resolution (1μm resolution can be achieved with conventional modulation methods) using extremely fine probes (only about 100 micrometers in diameter), offering significant advantages in applications with limited or confined spaces. This technology shows broad application prospects in fields such as in vivo endoscopic diagnosis, industrial endoscopic inspection, and life science research. However, single-strand multimode fiber imaging technology also faces some challenges. For example, the imaging field of view is small, limited by the numerical aperture and core diameter of the fiber, typically only about 100 micrometers. Furthermore, the working distance is short; in conventional multimode fiber microscopy, the distance between the fiber and the sample is usually within 100 micrometers. This problem stems from two factors: firstly, the sample signal is weak, making signal collection difficult; secondly, the focal point quality deteriorates as the beam propagates to the far field, thus affecting image resolution.

[0004] To overcome these limitations, researchers are exploring how to use multimode fiber for long-distance imaging. By combining wavefront shaping techniques and computational optics methods, the propagation characteristics of the beam can be optimized, improving the resolution and signal quality of far-field imaging. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a near-field and far-field tunable imaging device and method based on optical fiber. This device, based on conventional multimode fiber endoscopic imaging, replaces a single multimode fiber with a bundle of multiple multimode fibers and introduces Fourier transform at the modulation end, enabling the incident light to form a nearly parallel outgoing light field after modulation, thereby forming a scanning point in the far field. By alternately switching the near-field and far-field matrices, compatible acquisition of near-field and far-field images is achieved, thus simultaneously realizing near-field and far-field imaging modes through the optical fiber.

[0006] The specific technical solution adopted in this invention is as follows:

[0007] In a first aspect, the present invention provides a near-field and far-field tunable imaging device based on optical fiber, including a light source beam splitting component, a wavefront shaping component, an interferometric measurement component, and a signal receiving component;

[0008] The light source beam splitting component is used to split the narrow linewidth laser emitted from the narrow linewidth laser into a first beam and a second beam after being expanded and collimated by a first lens, a half-wave plate and a polarizing beam splitter in a controllable intensity; the first beam is used to enter the interferometric measurement component and the second beam is used to enter the wavefront shaping component.

[0009] The wavefront shaping component is used to phase modulate the second beam through a digital micromirror array, a second lens, a third lens, and a first microscope objective so that it enters the multimode fiber bundle light source end.

[0010] The interferometric measurement assembly is used to interfere with the reference light emitted from the first beam through the third microscope objective, single-mode fiber and fourth microscope objective with the probe light emitted from the multimode fiber bundle probe end through the second microscope objective and fourth lens at the first beam splitter, and image it onto the camera.

[0011] The signal receiving component is used to receive the fluorescence signal or reflected laser signal of the sample, and includes a dichroic mirror, a first reflecting mirror, a second beam splitter, a fifth lens, a filter, and a photodetector. The sample signal returns to the multimode fiber bundle after passing through the multimode fiber bundle detection end and is split into two paths. The first path exits through the signal end of the multimode fiber bundle and enters the second beam splitter. The second path exits through the light source end of the multimode fiber bundle and passes sequentially through the first microscope objective, the dichroic mirror, and the first reflecting mirror before entering the second beam splitter. The light emitted from the second beam splitter passes sequentially through the fifth lens and the filter before entering the photodetector. The photodetector is used to receive and process the light intensity signal.

[0012] Preferably, the multimode fiber bundle light source end has a single-core structure, the multimode fiber bundle detection end has a multi-core parallel structure, and the multimode fiber bundle signal end has a multi-core structure.

[0013] Preferably, the rear focal plane of the second microscope objective coincides with the front focal plane of the fourth lens, and the rear focal plane of the fourth lens coincides with the detection surface of the camera.

[0014] Preferably, the filter is disposed in an easily switchable sliding insert type mounting base.

[0015] Preferably, the digital micromirror array, camera, and photodetector are connected to a computer.

[0016] Secondly, the present invention provides an imaging method utilizing the fiber-based near-field and far-field tunable imaging device described in any one of the first aspects, as follows:

[0017] S1: Connect the light source beam splitting component, wavefront shaping component, and interferometry component; connect the digital micromirror array and camera to the computer.

[0018] A narrow-linewidth laser is activated. After being expanded and collimated by a first lens, the laser beam sequentially enters a half-wave plate and a polarizing beam splitter, resulting in a controllable split into a first beam and a second beam. A matrix test set is uploaded to the digital micromirror array (DMI). The second beam, modulated by the DMI, is then narrowed by a second and third lens to match the entrance pupil size of the first microscope objective. This beam is then coupled through the first microscope objective into the multimode fiber bundle source end. The first beam is coupled to a single-mode fiber by the third microscope objective, collimated by a fourth microscope objective, and emitted as a reference beam. The beam emitted from the multimode fiber bundle detector end is collimated by the second microscope objective, emitted through the fourth lens, and emitted as a probe beam. The reference beam and probe beam interfere at the first beam splitter and are imaged onto a camera. The computer records the interference pattern of the probe beam and reference beam, calculates the transmission matrix of the multimode fiber, performs a Fourier transform on the transmission matrix to transform it to the frequency domain, and then concatenates the original matrix and the frequency domain matrix longitudinally to form a new matrix. This new matrix serves as the matrix test set, which is then uploaded to the DMI.

[0019] S2: Remove the interferometric measurement component, connect the signal receiving component, connect the photodetector to the computer, and place the target sample at the detection end of the multimode fiber bundle;

[0020] The sample signal is transmitted from the multimode fiber bundle detector end to the multimode fiber bundle signal end and the multimode fiber bundle light source end respectively; the outgoing light from the multimode fiber bundle signal end enters the photodetector sequentially through the second beam splitter, the fifth lens and the filter, and the outgoing light from the multimode fiber bundle light source end enters the photodetector sequentially through the first microscope objective, the dichroic mirror, the first reflecting mirror, the second beam splitter, the fifth lens and the filter; the photodetector transmits the acquired signal to the computer, and the computer divides the obtained signal into two frames and displays them separately, with the first frame corresponding to the near field and the second frame corresponding to the far field.

[0021] Preferably, in S2, the process of displaying images by the computer is set as follows: after the new matrix is ​​fully played, the collected continuous signals are used to generate two images, corresponding to near-field and far-field images.

[0022] Preferably, the second beam passes through one of the multimode optical fibers in the multimode fiber bundle and performs point scanning on the sample to form an image.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1) Compared with existing multimode fiber optic endoscopic imaging schemes, this invention can provide near-field and far-field images simultaneously, with both a large field of view and high resolution. It can achieve a wide range of target area search and high-resolution imaging in a specific field of view, thus solving the contradiction that the field of view and resolution cannot be balanced in actual use.

[0025] 2) This invention uses a multimode fiber bundle as the structure for collecting and exciting separately. The detection end is a probe with multiple fiber cores integrated. The collection end does not contain an excitation fiber, thus eliminating noise from the reflection of the fiber end face.

[0026] 3) This invention can achieve cross-scale fusion imaging, enabling in-situ acquisition of images of different scales without changing the device. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a fiber-optic-based near-field and far-field adjustable imaging device according to an embodiment of the present invention.

[0028] The figures are labeled as follows: 1. Narrow linewidth laser; 2. First lens; 3. Half-wave plate; 4. Polarizing beam splitter; 5. Digital micromirror array; 6. Second lens; 7. Third lens; 8. Dichroic mirror; 9. First microscope objective; 10. Multimode fiber bundle light source end; 11. Multimode fiber bundle detection end; 12. Multimode fiber bundle signal end; 13. Second microscope objective; 14. Fourth lens; 15. First beam splitter; 16. Camera; 17. Computer; 18. Third microscope objective; 19. Single-mode fiber; 20. Fourth microscope objective; 21. First reflecting mirror; 22. Second beam splitter; 23. Fifth lens; 24. Filter; 25. Photodetector.

[0029] Figure 2 This is a diagram of a branched structure of a multimode fiber bundle, which contains several independent multimode fibers that form the detection end, the light source end, and the signal end, respectively.

[0030] Figure 3 The process of obtaining the transfer matrix by measurement includes Fast Fourier Transform and synthesis of a new matrix.

[0031] Figure 4 This is a flowchart of the imaging process. Detailed Implementation

[0032] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0033] To address the limitations of existing multimode fiber near-field imaging, such as its small field of view and incompatibility with far-field imaging, this invention provides a fiber-based near- and far-field adjustable imaging device, such as... Figure 1As shown. This device is based on phase modulation, using a multimode fiber bundle as the probe for excitation and reception signals, and achieves near-field and far-field synchronous imaging without changing the system through frequency domain modulation. The imaging device of this invention mainly includes a light source beam splitting component, a wavefront shaping component, an interferometry component, and a signal receiving component.

[0034] The structure and connection methods of each component will be explained in detail below.

[0035] In the device of this invention, the light source beam splitting assembly mainly includes a narrow-linewidth laser 1, a first lens 2, a half-wave plate 3, and a polarizing beam splitter 4, used to split the laser beam emitted from the laser into a reference beam (first beam) and a probe beam (second beam). Specifically, in use, the light source beam splitting assembly can expand and collimate the narrow-linewidth laser emitted from the narrow-linewidth laser 1 through the first lens 2, the half-wave plate 3, and the polarizing beam splitter 4, and then controllably split the light intensity into a first beam and a second beam. The first beam then enters the interferometry assembly, and the second beam then enters the wavefront shaping assembly.

[0036] In a preferred embodiment of the present invention, a narrow-linewidth laser 1, a first lens 2, a half-wave plate 3, and a polarizing beam splitter 4 are arranged sequentially along the optical path direction to form an optical system capable of realizing an optical path. Specifically, the narrow-linewidth laser 1 provides laser light with good interference properties, the first lens 2 is used for beam expansion and collimation, and the half-wave plate 3 and polarizing beam splitter 4 are used for controllable beam splitting.

[0037] In the device of this invention, the wavefront shaping component mainly includes a digital micromirror array (DMD) 5, a second lens 6, a third lens 7, and a first microscope objective 9. In practical use, the second beam can be phase-modulated (i.e., the light field of the incident fiber is phase-encoded) by the DMD 5 through the sequential passage of the DMD 5, second lens 6, third lens 7, and first microscope objective 9. The beam diameter is then reduced by the lens group (including a 4F structure composed of the second lens 6 and the third lens 7) to match the entrance pupil size of the first microscope objective 9, thereby coupling the beam into the multimode fiber bundle light source end 10. The first microscope objective 9 is used for coupling the beam to the fiber.

[0038] In a preferred embodiment of the present invention, the digital micromirror array 5, the second lens 6, the third lens 7, and the first microscope objective 9 are arranged sequentially along the optical path direction, together constituting an optical system capable of realizing an optical path. In this embodiment, the fiber end face of the light source should be placed at the working distance of the microscope objective.

[0039] In the device of this invention, the interferometry assembly mainly includes a third microscope objective 18, a single-mode fiber 19, a fourth microscope objective 20, a second microscope objective 13, a fourth lens 14, a first beam splitter 15, and a camera 16. It is used to interfere with the reference light by the light field emitted from the probe fiber (i.e., the multimode fiber bundle), record the interference pattern, and calculate the phase distribution of the light field emitted from the probe fiber, thereby providing a basis for wavefront shaping. In actual use, the reference light emitted from the first beam after passing sequentially through the third microscope objective 18, the single-mode fiber 19, and the fourth microscope objective 20, interferes with the probe light emitted from the multimode fiber bundle probe end 11 through the second microscope objective 13 and the fourth lens 14 at the first beam splitter 15, and the image is captured on the camera 16. The reference light emitted from the single-mode fiber interferes with the probe light emitted from the multimode fiber at the first beam splitter 15, and the image is captured on the camera 16.

[0040] In other words, the second microscope objective 13 and the fourth lens 14 are arranged sequentially along the direction of the probe light, while the third microscope objective 18, the single-mode fiber 19, the fourth microscope objective 20, the first beam splitter 15, and the camera 16 are arranged sequentially along the direction of the reference beam propagation. The third microscope objective 18 is used to couple the first beam into the single-mode fiber 19, and the fourth microscope objective 20 is used to collimate the light emitted from the single-mode fiber 19 as a reference light. The probe light emitted from the multimode fiber interferes with the reference light emitted from the single-mode fiber at the first beam splitter 15, and the fourth lens 14 is used to focus the interference pattern onto the target surface of the camera 16.

[0041] In a preferred embodiment of the present invention, the distances between the second microscope objective 13, the fourth lens 14, and the camera 16 are set according to the correspondence between the frequency domain and the spatial domain. Specifically, the rear focal plane of the second microscope objective 13 coincides with the front focal plane of the fourth lens 14, and the rear focal plane of the fourth lens 14 coincides with the detection surface of the camera 16. In actual use, the probe light passes through the multimode fiber bundle and, through the combined action of the second microscope objective 13 and the fourth lens 14, magnifies the outgoing light spot onto the camera's imaging surface. The third microscope objective 18 is used to couple the first beam into the single-mode fiber 19, and the fourth microscope objective 14 is used to collimate the outgoing light from the single-mode fiber as a reference light. The probe light and the reference light exiting through the fiber interfere at the first beam splitter 15.

[0042] In the device of this invention, the signal receiving component is used to receive the fluorescence signal or reflected laser signal of the sample, and mainly includes a dichroic mirror 8, a first reflecting mirror 21, a second beam splitter 22, a fifth lens 23, a filter 24, and a photodetector 25. The sample signal returns to the multimode fiber bundle via the detection end 11, and is then split into two paths. The first path exits through the signal end 12 of the multimode fiber bundle and enters the second beam splitter 22. The second path exits through the light source end 10 of the multimode fiber bundle and passes sequentially through the first microscope objective 9, the dichroic mirror 8, and the first reflecting mirror 21 before entering the second beam splitter 22. The light emitted from the second beam splitter 22 passes sequentially through the fifth lens 23 and the filter 24 before entering the photodetector 25. The filter 24 needs to switch corresponding parameters as required, and the photodetector 25 is used to receive and process the light intensity signal.

[0043] In practical applications, the multimode fiber bundle has a branched structure, which allows for the separation of the excitation and collection optical paths. If used to receive fluorescence signals, one branch is used for both excitation and collection, while the other is used for collection. If only the laser reflected from the sample is collected, one branch is used solely for excitation, and the other for collection. In other words, for fluorescence detection, the signal returns to the fiber via the original path from the detector end, passes through the light source end, and then enters the photodetector 25 via the dichroic mirror 8 and the signal end 12. For reflected laser signals, the signal enters the photodetector only through the signal end 12.

[0044] In a preferred embodiment of the present invention, the filter 24 should be disposed in an easily switchable sliding insert type mounting base.

[0045] As a preferred embodiment of the present invention, the multimode fiber bundle should be configured as follows: the connection end with the wavefront shaping component (i.e., the light source end 10 of the multimode fiber bundle) is a single-core structure, the contact end with the sample (i.e., the detection end 11 of the multimode fiber bundle) is a multi-core parallel structure, and the connection end with the signal receiving component (i.e., the signal end 12 of the multimode fiber bundle) is a multi-core structure.

[0046] For example Figure 2 The multimode fiber bundle shown contains multiple fibers, each independent of the others, eliminating mode crosstalk. During imaging, the central fiber at the detector end is used for illumination, with its other end located at the light source. Multiple other fibers, all connected to the signal source, surround the central fiber, allowing for the acquisition of more detection signals and improving the image signal-to-noise ratio.

[0047] In a preferred embodiment of the present invention, the digital micromirror array 5, the camera 16, and the photodetector 25 should be connected to the computer 17 respectively. Figure 1(Connecting lines are not shown). Among them, the digital micromirror array 5 is connected to the computer 17 to pre-upload test patterns for calculating the transmission matrix, the camera 16 is connected to the computer 17 to realize the rapid storage of interference patterns, and the photodetector 25 is connected to the computer 17 to receive and save real-time voltage signals.

[0048] Utilizing the aforementioned fiber-optic-based near- and far-field adjustable imaging device, this invention also provides an imaging method, such as... Figure 4 As shown, the method is as follows:

[0049] S1: Connect the light source beam splitting component, wavefront shaping component, and interferometry component, and connect the digital micromirror array 5 and camera 16 to computer 17.

[0050] The narrow-linewidth laser 1 is turned on. After being expanded and collimated by the first lens 2, the narrow-linewidth laser beam sequentially enters the half-wave plate 3 and the polarizing beam splitter 4, splitting into a first beam and a second beam with controllable intensity. The computer 17 uploads a matrix test set to the digital micromirror array 5. The second beam, after being modulated by the digital micromirror array 5, is then narrowed by the second lens 6 and the third lens 7 to match the entrance pupil size of the first microscope objective 9. The beam is then coupled through the first microscope objective 9 into the multimode fiber bundle source end 10. The first beam (i.e., the parallel beam) is coupled to the single-mode fiber 19 by the third microscope objective 18, and then collimated by the fourth microscope objective 20 and emitted as a reference beam. The beam emitted from the multimode fiber bundle detector end 11 is collimated by the second microscope objective 13 and emitted through the fourth lens 14 as a probe beam. The reference beam emitted from the single-mode fiber and the probe beam emitted from the multimode fiber interfere at the first beam splitter 15 and are imaged onto the camera 16. The computer 17 records the interference pattern of the probe light and the reference light, calculates the transmission matrix of the multimode fiber, performs a Fourier transform on the transmission matrix to transform it to the frequency domain, and then concatenates the original matrix and the frequency domain matrix vertically to merge them into a new matrix. Figure 3 As shown. The new matrix, used as a matrix test set, is then uploaded to the digital micromirror array 5 to modulate the second beam.

[0051] In other words, the first beam is transmitted sequentially through the third microscope objective 18, single-mode fiber 19, and fourth microscope objective 20, and then enters the first beam splitter 15 as a reference beam. The second beam is manipulated by a wavefront shaping component, and then enters the first beam splitter 15 as a probe beam after passing through a multimode fiber bundle. By continuously changing the orthogonal measurement basis loaded on the DMD, the camera 16 records the interference pattern of the reference beam and probe beam of the first beam splitter 15, and the information of the object beam is recovered by off-axis holography. The phase distortion of the beam after transmission through the fiber is calculated using a computer 17. The measured transmission matrix is ​​subjected to a fast Fourier transform to obtain a new frequency domain matrix. The two matrices are connected to form a new matrix, which is then loaded onto the digital micromirror array 5.

[0052] S2: Remove the interferometric measurement component, connect the signal receiving component, connect the photodetector 25 to the computer 17, and place the target sample at the multimode fiber bundle detection end 11.

[0053] The sample signal is transmitted from the multimode fiber bundle detector 11 to the multimode fiber bundle signal 12 and the multimode fiber bundle light source 10, respectively. The light emitted from the multimode fiber bundle signal 12 passes sequentially through the second beam splitter 22, the fifth lens 23, and the filter 24 before entering the photodetector 25. The light emitted from the multimode fiber bundle light source 10 passes sequentially through the first microscope objective 9, the dichroic mirror 8, the first reflecting mirror 21, the second beam splitter 22, the fifth lens 23, and the filter 24 before entering the photodetector 25. The photodetector 25 transmits the acquired signal to the computer 17, which divides the signal into two frames and displays them separately. The first frame corresponds to the near field, and the second frame corresponds to the far field.

[0054] In other words, based on compensating for fiber phase distortion, the outgoing light field of the fiber is controlled to form a continuously scanning focal point. The fiber is used to collect sample signals, which are reflected by the dichroic mirror 8 and the second beam splitter 22 and focused onto the photodetector 25 by the fifth lens 23. By repeatedly playing the new matrix obtained in S1, near-field and far-field imaging modes can be realized simultaneously. The near-field mode and the far-field mode correspond to two consecutive frames of the acquired image, respectively. By setting external timing control, the two frames are displayed and saved independently. To further enhance the system's representation capability and improve visualization, the computer 17 can use the near-field and far-field images for feature extraction and matching, and achieve visualization overlay and fusion through multi-constraint optimization such as edge alignment and region similarity.

[0055] In a preferred embodiment of the present invention, in S2, the process of computer 17 displaying images is set as follows: after the new matrix is ​​fully played, the collected continuous signals are used to generate two images, corresponding to near-field and far-field images.

[0056] In a preferred embodiment of the present invention, the second beam (i.e., the modulated beam) should pass through one of the multimode optical fibers in the multimode fiber bundle and perform point scanning on the sample for imaging.

[0057] This invention is based on frequency domain modulation and utilizes a specially designed detection and collection module to achieve synchronous compatibility between near-field and far-field imaging.

[0058] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A near-field and far-field adjustable imaging device based on optical fiber, characterized in that, It includes a light source beam splitting assembly, a wavefront shaping assembly, an interferometry assembly, and a signal receiving assembly; The light source beam splitting component is used to split the narrow linewidth laser emitted from the narrow linewidth laser (1) into a first beam and a second beam after beam expansion and collimation by the first lens (2), half-wave plate (3) and polarizing beam splitter (4); the first beam is used to enter the interferometric measurement component, and the second beam is used to enter the wavefront shaping component. The wavefront shaping component is used to phase modulate the second beam through the digital micromirror array (5), the second lens (6), the third lens (7) and the first microscope objective (9) so that it enters the multimode fiber bundle light source end (10). The interferometric measurement assembly is used to interfere the reference light emitted from the first beam through the third microscope objective (18), single-mode fiber (19) and the fourth microscope objective (20) with the probe light emitted from the multimode fiber bundle probe end (11) through the second microscope objective (13) and the fourth lens (14) at the first beam splitter (15), and image it onto the camera (16). The signal receiving component is used to receive the fluorescence signal or reflected laser signal of the sample, including a dichroic mirror (8), a first reflecting mirror (21), a second beam splitter (22), a fifth lens (23), a filter (24), and a photodetector (25). The sample signal is returned to the multimode fiber bundle from the multimode fiber bundle detection end (11) and then split into two paths. The first path is emitted from the multimode fiber bundle signal end (12) and enters the second beam splitter (22). The second path is emitted from the multimode fiber bundle light source end (10) and passes through the first microscope objective (9), the dichroic mirror (8), and the first reflecting mirror (21) in sequence before entering the second beam splitter (22). The emitted light from the second beam splitter (22) passes through the fifth lens (23) and the filter (24) in sequence before entering the photodetector (25). The photodetector (25) is used to receive and process the light intensity signal. The digital micromirror array (5), camera (16), and photodetector (25) are connected to the computer (17). The computer (17) uploads a matrix test set to the digital micromirror array (5). After the second beam is modulated by the digital micromirror array (5), it is condensed by the second lens (6) and the third lens (7) to match the entrance pupil size of the first microscope objective (9). The beam is then coupled into the multimode fiber bundle light source end (10) through the first microscope objective (9). The first beam is coupled to the single-mode fiber (19) through the third microscope objective (18), and then collimated and emitted by the fourth microscope objective (20). As a reference light; the beam emitted from the multimode fiber bundle detector end (11) is collimated by the second microscope objective (13) and emitted through the fourth lens (14) as the probe light; the reference light and the probe light interfere at the first beam splitter (15) and are imaged on the camera (16); the interference pattern of the probe light and the reference light is recorded by the computer (17), the transmission matrix of the multimode fiber is calculated, the transmission matrix is ​​Fourier transformed to transform it to the frequency domain, and the original matrix and the frequency domain matrix are spliced ​​together in the longitudinal direction to merge into a new matrix; the new matrix is ​​used as a matrix test set for uploading to the digital micromirror array (5).

2. The fiber-optic-based near-field and far-field adjustable imaging device according to claim 1, characterized in that, The multimode fiber bundle light source end (10) has a single-core structure, the multimode fiber bundle detection end (11) has a multi-core parallel structure, and the multimode fiber bundle signal end (12) has a multi-core structure.

3. The fiber-optic-based near-field and far-field adjustable imaging device according to claim 1, characterized in that, The back focal plane of the second microscope objective (13) coincides with the front focal plane of the fourth lens (14), and the back focal plane of the fourth lens (14) coincides with the detection surface of the camera (16).

4. The fiber-optic-based near-field and far-field adjustable imaging device according to claim 1, characterized in that, The filter (24) is disposed in an easily switchable sliding insert mounting base.

5. An imaging method using the fiber-optic-based near-field and far-field adjustable imaging device according to any one of claims 1 to 4, characterized in that, Specifically as follows: S1: Connect the light source beam splitting component, wavefront shaping component and interferometry component, and connect the digital micromirror array (5) and camera (16) to computer (17); The narrow-linewidth laser (1) is turned on. After being expanded and collimated by the first lens (2), the narrow-linewidth laser enters the half-wave plate (3) and the polarizing beam splitter (4) in sequence, and the controllable light intensity is split into the first beam and the second beam. The computer (17) uploads the matrix test set to the digital micromirror array (5). After being modulated by the digital micromirror array (5), the second beam is condensed by the second lens (6) and the third lens (7) to match the entrance pupil size of the first microscope objective (9). The beam is then coupled into the multimode fiber bundle source end (10) through the first microscope objective (9). The first beam is coupled to the single-mode fiber (19) through the third microscope objective (18), and then through the fourth... The light emitted from the microscope objective (20) is collimated and used as a reference light; the beam emitted from the multimode fiber bundle detector end (11) is collimated by the second microscope objective (13) and emitted through the fourth lens (14) as a probe light; the reference light and the probe light interfere at the first beam splitter (15) and are imaged on the camera (16); the interference pattern of the probe light and the reference light is recorded by the computer (17), the transmission matrix of the multimode fiber is calculated, the transmission matrix is ​​Fourier transformed to transform it to the frequency domain, and the original matrix and the frequency domain matrix are spliced ​​vertically to merge into a new matrix; the new matrix is ​​used as a matrix test set for uploading to the digital micromirror array (5). S2: Remove the interferometric measurement component, connect the signal receiving component, connect the photodetector (25) to the computer (17), and place the target sample at the multimode fiber bundle detection end (11). The sample signal is transmitted from the multimode fiber bundle detector (11) to the multimode fiber bundle signal end (12) and the multimode fiber bundle light source end (10), respectively. The outgoing light from the multimode fiber bundle signal end (12) passes through the second beam splitter (22), the fifth lens (23) and the filter (24) in sequence and enters the photodetector (25). The outgoing light from the multimode fiber bundle light source end (10) passes through the first microscope objective (9), the dichroic mirror (8), the first reflector (21), the second beam splitter (22), the fifth lens (23) and the filter (24) in sequence and enters the photodetector (25). The photodetector (25) transmits the acquired signal to the computer (17). The computer (17) divides the obtained signal into two frames and displays them respectively. The first frame corresponds to the near field and the second frame corresponds to the far field.

6. The imaging method according to claim 5, characterized in that, In S2, the process of the computer (17) displaying the image is set as follows: after the new matrix is ​​fully played, the collected continuous signals are used to generate two images, corresponding to the near field and far field images.

7. The imaging method according to claim 5, characterized in that, The second beam passes through one of the multimode optical fibers in the multimode fiber bundle and performs point scanning on the sample to form an image.

Images