Phase feedback compensation quasi-real-time calibration interference imaging device and imaging method

Abstract

The invention relates to an interference imaging device for phase feedback compensation quasi-real-time calibration, and belongs to the technical field of interference imaging. The calibration device comprises an X / Y direction light path, a controller and a linear displacement table. The X-direction light path structure and the Y-direction light path structure are the same, and each of the X-direction light path structure and the Y-direction light path structure comprises two parallel coupling lenses, an interference assembly and a photoelectric detection assembly which are sequentially arranged in the light incidence direction; the linear displacement table is cross-shaped; four paths of coupling lenses of the X-direction light path and the Y-direction light path are fixed through a linear displacement table and are uniformly arranged around the central point of the cross-shaped linear displacement table; the interference assembly receives the light beams output by the two parallel coupling lenses, performs phase modulation on the light beams, enables the two light beams to perform interference, and outputs an interference light signal to the photoelectric detection assembly; the photoelectric detection assembly converts the interference optical signal into an interference electric signal; the controller is used for sending a control signal to the interference assembly to control phase modulation of the interference assembly and receiving an interference electric signal output by the photoelectric detection assembly.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of interferometric imaging technology, and in particular to an interferometric imaging device and imaging method with phase feedback compensation quasi-real-time calibration. BACKGROUND

[0002] A conventional imaging system is composed of an optical telescope and a detector, and has a long production cycle, high development cost, large volume and weight. Interferometric imaging technology is an effective means for space exploration. An interferometer control system collects light signals from multiple sub-apertures, corrects phase differences using an optical path compensator, combines light beams to form an interference pattern, and finally obtains a good observation image. Although the interferometric imaging system has obvious advantages over the conventional optical system, it is relatively sensitive to environmental factors such as external vibration and temperature fluctuation. When the light beam is transmitted in the system, since the interferometric imaging relies on the high-precision phase relationship between light waves, any slight environmental disturbance can cause a change in the optical path difference, thereby causing the interference to drift or distort, seriously affecting the quality and reliability of image reconstruction, and affecting the measurement of complex visual information.

[0003] The interferometer control system is usually arranged in a laboratory and has vibration isolation and thermal regulation functions to maintain a stable working state, and it is difficult to adapt to a mobile platform with limited space in harsh environments. At present, efficient and practical interferometric image detection methods are still very limited, and a phase feedback compensation quasi-real-time calibration interferometric imaging system is needed to meet the requirements of high reliability and high quality imaging. SUMMARY

[0004] In view of the above analysis, the embodiments of the present application aim to provide an interferometric imaging device and imaging method with phase feedback compensation quasi-real-time calibration to solve the problem of poor imaging effect of the existing interferometer control system affected by the external environment.

[0005] In one aspect, the embodiments of the present application provide an interferometric imaging device with phase feedback compensation quasi-real-time calibration. The calibration device includes an X-direction optical path, a Y-direction optical path, a controller, and a linear displacement table.

[0006] The X-direction optical path and the Y-direction optical path have the same structure and each include two parallel coupling lenses, an interference assembly and a photoelectric detection assembly arranged in sequence along the light incident direction.

[0007] The linear displacement table is cross-shaped; the four coupling lenses of the X-direction optical path and the Y-direction optical path are fixed by the linear displacement table and are uniformly arranged around the center point of the cross-shaped linear displacement table.

[0008] The interference component receives two parallel coupled lens output beams and modulates the phase of the beams to make the two beams interfere, and outputs an interference light signal to the photoelectric detection component; the photoelectric detection component converts the interference light signal into an interference electric signal;

[0009] The controller is used to send a control signal to the interference component to control the phase modulation of the interference component, and receive the interference electric signal output by the photoelectric detection component.

[0010] The interference component includes a beam splitting component, a phase shifter group and a 2×1 fiber coupler in sequence along the light incident direction;

[0011] The phase shifter group includes a main phase shifter and an auxiliary phase shifter;

[0012] The photoelectric detection component includes first to third photoelectric detectors;

[0013] The beam splitting component includes two beam splitting devices, each corresponding to a coupling lens, and each splitting device splits the light beam output by the corresponding coupling lens into an interference sub-beam and an independent sub-beam; the two independent sub-beams output by the two beam splitting devices are respectively output to the second and third photoelectric detectors; the two interference sub-beams output by the two beam splitting devices are respectively input to the main phase shifter and the auxiliary phase shifter; the main phase shifter and the auxiliary phase shifter input the phase-shifted light beams to the 2×1 fiber coupler, and the 2×1 fiber coupler outputs the interference light signal to the first photoelectric detector.

[0014] The main phase shifter is a piezoelectric ceramic phase shifter; the piezoelectric ceramic phase shifter receives a voltage signal output by the controller and outputs a phase-shifted light signal; the auxiliary phase shifter is a fiber phase shifter.

[0015] The calibration device further includes a movement controller, a plurality of servo motors and a plurality of lens clamping pieces, each lens clamping piece corresponding to a coupling lens and a servo motor; the lens clamping pieces are installed on a linear displacement table and used to fix the coupling lenses; the plurality of servo motors drive the lens clamping pieces to move under the control of the movement controller, and in turn drive the coupling lenses to move along the linear displacement table.

[0016] The clear aperture range of each coupling lens is 3-8mm.

[0017] The beam splitting device is a 1×2 fiber coupler or an optical beam splitter.

[0018] The device further includes a calibration light source; the calibration light source is located directly in front of the centers of the four coupling lenses; the calibration light source is turned on or off under the action of the controller.

[0019] The device further includes a signal processor connected with the controller, used to receive the output signal of the detector component sent by the controller and display and process the signal.

[0020] The device also comprises an optical switch which is opened or closed under the action of the controller.

[0021] In another aspect, the embodiment of the present application provides an imaging method based on the interference imaging device, and the method comprises steps S1-S3:

[0022] S1, the calibration light source is turned on, the controller outputs a sinusoidal varying voltage signal to the piezoelectric ceramic phase shifter, the maximum value of the interference electric signal is found, and the controller records the voltage signal at the maximum value of the interference electric signal;

[0023] The calibration light source is turned off, the target light source is collected, the controller outputs a voltage signal corresponding to the maximum value of the interference electric signal to the piezoelectric ceramic phase shifter, and the signal output by the photoelectric detection assembly is recorded;

[0024] S2, the calibration light source is turned on again, the controller outputs a sinusoidal varying voltage signal to the piezoelectric ceramic phase shifter, the voltage signal corresponding to the interference light intensity I1+I2 of the interference electric signal is found, I1 and I2 are the light intensities entering the main phase shifter and the auxiliary phase shifter respectively, and the controller records the voltage signal; the calibration light source is turned off, the target light source is collected, the controller outputs a voltage signal corresponding to the interference light intensity I1+I2 of the interference electric signal to the piezoelectric ceramic phase shifter, and the signal output by the photoelectric detection assembly is recorded;

[0025] S3, the position of the coupling lens on the linear displacement table is changed multiple times to change the interference baseline length, steps S1-S2 are repeated, the interference light and the independent sub-beam under the action of the target light source are detected by the photoelectric detection assembly and transmitted to the controller, and the controller inversely calculates the intensity distribution of the target light source until a clear target light source is output.

[0026] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0027] 1. In the interference imaging device, the coupling lens is moved along the linear displacement table by the servo motor, the adjustment of the interference baseline length is realized, and the target is restored by a small number of small-diameter coupling lenses. Few optical elements are used, the structure is simple, and the optical imaging requirements of light weight, high resolution and low weight power consumption can be met.

[0028] 2. In the interference imaging device, the calibration light source is added, the environmental interference signal is detected, the phase feedback compensation is applied by the piezoelectric ceramic phase shifter, the signal jitter caused by the environmental interference is solved, and the restoration of the high-quality target image is realized.

[0029] 3. The application provides a calibration method of an interference imaging device based on phase feedback compensation quasi-real-time calibration, which detects the interference signal in the environment when the calibration light source is turned on, and compensates by using the phase feedback compensation method, effectively solves the interference signal jitter caused by environmental interference, realizes stable measurement of the interference signal, and completes the restoration of the high-quality target image.

[0030] The above technical solutions can be combined with each other in the application to realize more preferred combination solutions. Other features and advantages of the application will be described in the subsequent description, and some advantages will become apparent from the description, or will be understood by implementing the application. The purposes and other advantages of the application can be realized and obtained from the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0032] Figure 1 A schematic diagram of the composition structure of the interference imaging device of the application based on phase feedback compensation quasi-real-time calibration;

[0033] Figure 2 The interference light intensity output by different baseline lengths under a certain target light source of the application;

[0034] Figure 3 The target restoration result under a certain target light source of the application.

[0035] Reference signs:

[0036] 1, 6 - coupling lens;

[0037] 2, 7 - beam splitting device;

[0038] 3 - piezoelectric ceramic phase shifter;

[0039] 4 - 2x1 optical fiber coupler;

[0040] 5 - photoelectric detection assembly;

[0041] 8 - optical fiber phase shifter;

[0042] 10 - linear displacement table;

[0043] 11 - lens clamping piece;

[0044] 14 - calibration light source;

[0045] 15 - optical switch;

[0046] 16 - controller;

[0047] 17 - signal processor. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which form a part of this application. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. It should be noted that the drawings are in simplified form and are not to precise proportions. In addition, elements that are known per se or not necessary for understanding the present application are not shown in order not to obscure the concepts of the present application.

[0049] One specific embodiment of the present application discloses an interference imaging device with phase feedback compensation quasi-real-time calibration, as shown in the figure. The calibration device comprises an X-direction light path, a Y-direction light path, a controller 16, a linear displacement stage 10. Figure 1 The X-direction light path and the Y-direction light path have the same structure, and each comprises two parallel coupled lenses, an interference component and a photoelectric detection component 5 arranged in sequence along the light incident direction.

[0050] The X-direction light path and the Y-direction light path have the same structure, and each comprises two parallel coupled lenses, an interference component and a photoelectric detection component 5 arranged in sequence along the light incident direction.

[0051] The linear displacement stage 10 is cross-shaped; the four coupled lenses of the X-direction light path and the Y-direction light path are fixed by the linear displacement stage 10 and are uniformly arranged around the center point of the cross-shaped linear displacement stage 10.

[0052] The interference component receives the light beams output by the two parallel coupled lenses 1, 6 and modulates the phase of the light beams to make the two light beams interfere, and outputs the interference light signal to the photoelectric detection component 5; the photoelectric detection component 5 converts the interference light signal into an interference electric signal.

[0053] The controller 16 is used to send a control signal to the interference component to control the phase modulation of the interference component, and receive the interference electric signal output by the photoelectric detection component 5.

[0054] The clear aperture range of each coupled lens is 3-8 mm.

[0055] Specifically, the coupled lenses 1, 6 are used to collect light beams and couple them into optical fibers, and the size of the aperture determines the energy collection efficiency of the system. The apertures of the coupled lens 1 and the coupled lens 6 can be the same or different.

[0056] The device further comprises a calibration light source 14; the calibration light source 14 is located directly in front of the center of the four coupled lenses; the calibration light source 14 is turned on or off under the action of the controller 16.

[0057] Specifically, the calibration light source 14 is used to compensate for the interference signal in the environment. There will inevitably be vibration or temperature change in the environment, and if the target light source is far away or the light intensity is weak, the interference light signal will inevitably be affected, but the calibration light source 14 is relatively close to the interference imaging device, and the light intensity is relatively strong, so it can compensate for the environmental interference in the process of finding the 0π phase and the interference imaging device.

[0058] In one embodiment of the present application, the SLED 1550 wide spectrum calibration light source 14 is used.

[0059] The device also comprises an optical switch 15, which is opened or closed by the controller 16.

[0060] The interference assembly comprises, in order along the light incident direction, a beam splitting assembly, a phase shifter group, and a 2x1 fiber coupler 4.

[0061] The phase shifter group comprises a main phase shifter and a sub phase shifter.

[0062] The photoelectric detection assembly 5 comprises first to third photoelectric detectors.

[0063] The beam splitting assembly comprises two beam splitting devices 2, 7, each of which corresponds to a coupling lens, and each of which splits the light beam output by the corresponding coupling lens into an interference sub-beam and an independent sub-beam; the independent sub-beams output by the two beam splitting devices 2, 7 are output to the second and third photoelectric detectors, respectively; the interference sub-beams output by the two beam splitting devices 2, 7 are output to the main phase shifter and the sub phase shifter, respectively; the main phase shifter and the sub phase shifter input the phase-shifted light beams to the 2x1 fiber coupler 4, and the 2x1 fiber coupler 4 outputs the interference light signal to the first photoelectric detector.

[0064] The beam splitting devices 2, 7 are 1x2 fiber couplers or optical beam splitters.

[0065] The 1x2 fiber coupler is used to split the light beams collected by the coupling lenses 1, 6, and in one embodiment of the present application, the splitting ratio is 10 / 90; the two output ports with a splitting energy of 10% are connected to the second and third photoelectric detectors, respectively, to detect the incoherent light intensities (independent sub-beams) collected by the two channels, respectively; and one end of the two 1x2 fiber couplers with a splitting energy of 90% is connected to the phase shifter in each channel, respectively.

[0066] The piezoelectric ceramic phase shifter 3 is used to introduce the phase difference required for interference detection of the light beams in the optical fiber.

[0067] The 2x1 fiber coupler 4 is used to combine the phase-shifted light beams, and the splitting ratio of the two split light beams at the input end of the 2x1 fiber coupler 4 is 50 / 50; the two input ports of the 2x1 fiber coupler 4 are connected to the output ports of the phase shifters in the two channels through fiber jumpers, respectively; and the output port is directly coupled to the first photoelectric detector for interference light intensity detection.

[0068] The photoelectric detector is used to receive the interference light signal and the independent sub-beam output light field, and to realize detection of coherent and incoherent signals.

[0069] The fiber phase shifter 8 is a type of VDL-MAR-33-15 of Tianjin Junfeng, and the fiber phase shifter 8 is an optical path compensator. It is a reflective optical path manual delay line, adopts a low insertion loss corner cube prism, and has high phase modulation precision. The optical path compensator is used for compensating an additional optical path difference introduced by an internal optical fiber of a phase delay device, and has a large phase modulation amount.

[0070] The fiber phase shifter 8 is used for coarsely adjusting an optical path difference of a light beam in an optical fiber, and introduces a required phase difference for interference detection. The fiber phase shifter 8 adopts a manual knob adjustment, and is adjusted before starting measurement, so that two optical paths are approximately equal, and interference conditions are achieved.

[0071] The main phase shifter is a piezoelectric ceramic phase shifter 3; the piezoelectric ceramic phase shifter 3 receives an output voltage signal of the controller 16, and outputs a phase-shifted optical signal; and the auxiliary phase shifter is a fiber phase shifter 8.

[0072] The calibration device further comprises a movement controller 16, a plurality of servo motors, and a plurality of lens holders 11, each lens holder 11 corresponds to a coupling lens, and each servo motor drives a corresponding lens holder 11 to move; the lens holders 11 are installed on the linear displacement table 10, and are used for fixing the coupling lenses 1 and 6; and the plurality of servo motors drive the lens holders 11 to move under the control of the movement controller 16, so as to drive the coupling lenses 1 and 6 to move along the linear displacement table 10.

[0073] The lens holders 11 are used for clamping the coupling lenses 1 and 6 and are fixed on the linear displacement table 10.

[0074] The movement controller 16 is used for controlling the lens holders 11 to move along the tracks through the servo motors, so as to control the coupling lenses 1 and 6 to move along the linear displacement table 10, and realize adjustment of an interference baseline length.

[0075] The device further comprises a signal processor 17, which is connected with the controller 16, and is used for receiving and displaying and processing an output signal of the detector assembly sent by the controller 16.

[0076] Another specific embodiment of the present application further discloses an imaging method based on the interference imaging device, and the method comprises steps S1-S3.

[0077] S1, the calibration light source 14 is turned on, the controller 16 outputs a sinusoidal varying voltage signal to the piezoelectric ceramic phase shifter 3, a maximum value of an interference electric signal is found, and the controller 16 records a voltage signal at the maximum value of the interference electric signal;

[0078] The calibration light source 14 is turned off, a target light source is collected, the controller 16 outputs a voltage signal corresponding to the maximum value of the interference electric signal to the piezoelectric ceramic phase shifter 3, and a signal output by the photoelectric detection assembly 5 is recorded.

[0079] Specifically, the interference compensation signal is a continuous multi-period sinusoidal signal, which is used to adjust the phase of the input light beam of the piezoelectric phase shifter 3.

[0080] S2, the calibration light source 14 is turned on again, the controller 16 outputs a sinusoidal varying voltage signal to the piezoelectric phase shifter 3, and the voltage signal corresponding to the interference light intensity I1+I2 is found, I1 and I2 are the light intensities entering the main phase shifter and the auxiliary phase shifter respectively, and the controller 16 records the voltage signal; the calibration light source 14 is turned off, the target light source is collected, and the controller 16 outputs a voltage signal to the piezoelectric phase shifter 3 when the interference light intensity corresponding to the interference electric signal is stable at I1+I2, and records the signal output by the photoelectric detection assembly 5.

[0081] Specifically, when the observation target is far enough from the interference baseline, the output light intensity of the interference baseline is calculated as follows:

[0082]

[0083] In the formula, γ 12 = |γ 12 |e i·arg(γ12) is the complex visibility function of the target, which represents the component of the Fourier transform of the target light intensity distribution at the frequency corresponding to the baseline; I1 and I2 are the light intensities entering the main phase shifter and the auxiliary phase shifter; δ1 and δ2 are the internal optical path differences between the two channels (the light emitted from the target light source or the calibration light source 14 passes through the coupling lens 1, the 1×2 optical fiber coupler 2, the piezoelectric phase shifter 3, the 2×1 optical fiber coupler 4, and the photoelectric detector 5 to form the first channel; the light emitted from the target light source or the calibration light source 14 passes through the coupling lens 6, the 1×2 optical fiber coupler 7, the phase shifter 8, the 2×1 optical fiber coupler 4, and the photoelectric detector 5 to form the second channel; the difference between the optical paths of the two channels is the difference between the light fields of the two channels). δ1 , I δ2 are the output light intensities recorded when δ1=0,

[0084] The controller 16 controls the interference compensation signal so that the optical path phase difference of the interference light is 0π when the interference light intensity is stable at The controller 16 controls the interference compensation signal so that the optical path phase difference of the interference light is wherein I1 and I2 are the light intensities received by the main phase shifter and the auxiliary phase shifter respectively.

[0085] The interference baseline samples the spatial frequency of the target to obtain a frequency spectrum F(u,v), wherein the phase information of each frequency spectrum component of the target intensity distribution is and the amplitude |γ 12 | is calculated as follows:

[0086] ​

[0087] S3, the coupling lens 1, 6 is moved on the linear displacement table 10 to change the interference baseline length, and steps S1-S2 are repeated to detect the interference light and the independent sub-beam under the action of the target light source by the photoelectric detection assembly 5 and transmit to the controller 16, and the controller 16 inversely calculates the intensity distribution of the target light source according to the above, until the clear target light source is output.

[0088] Specifically, the two coupling lenses 1, 6 in the X / Y direction are respectively moved on the linear displacement table 10 to obtain variable X / Y direction interference baselines.

[0089] The arrangement of the coupling lenses 1, 6 can be converted into the u-v coverage of the imaging system, wherein the relationship between the target spatial spectrum and the interference baseline vector is: u is the x-direction spatial frequency, and v is the y-direction spatial frequency.

[0090]

[0091] In the formula, B x , B y respectively represent the projection vectors of the interference baseline in the plane perpendicular to the observation direction, and λ is the wavelength.

[0092] The interference light and the independent sub-beam under the action of the target light source are detected by the photoelectric detection assembly 5 and transmitted to the controller 16, and the amplitude and phase information of the spatial frequency of the target light source are obtained through the signal processor 17, and the intensity distribution of the target source is obtained through the Fourier inverse transform, that is, the image of the target. The length of the interference baseline affects the frequency spectrum F(u, v) of the system, and further determines the recovery effect of the target image.

[0093] The recorded experimental measurement data are substituted into formulas (1)-(2) to obtain the interference light intensity at 0π phase and π / 2 phase under different baseline lengths, and further obtain the complex visibility function in this detection direction. The target intensity distribution in this detection direction can be finally obtained by performing Fourier inverse transform on the complex visibility function.

[0094] In an embodiment of the present application, the simulation target is set as two separated point light sources located at the focal plane of the projection lens, the intensity ratio of which is 2:1, and the incident angles are-0.2 mrad and 0.1 mrad respectively after collimation by the projection lens; the emission spectrum distribution is Gaussian spectrum, the center wavelength is 1550 nm, and the resolution FWHM of the spectrometer is 10 nm. The aperture of the coupling lens 1, 6 in the interference baseline is set as 5 mm, and the interference light intensity simulation results output by each interference baseline are as shown in Figure 2 .

[0095] In an embodiment of the present application, the different baseline lengths and the corresponding interference light intensity amplitude records are as shown in Table 1.

[0096] Table 1

[0097]

[0098] By using Figure 2 The target intensity distribution spectrum is calculated by using the output signal, and the target intensity is obtained by inverse Fourier transform. Finally, the intensity is corrected according to the coupling efficiency of the lens at different field angles, and the target intensity distribution is obtained as shown in Figure 3

[0099] Compared with the prior art, in the interference imaging device provided by the embodiment, the coupling lenses 1 and 6 are controlled to move along the linear displacement table 10 by the servo motor, so that the interference baseline length is adjusted. The target is restored by using a small number of small-diameter coupling lenses 1 and 6. Few optical elements are used, and the structure is simple, so that the optical imaging requirements of light weight, high resolution and low weight power consumption can be met. The interference imaging device provided by the embodiment adds the calibration light source 14 to detect the environmental interference signal, and uses the piezoelectric ceramic phase shifter 3 to apply phase feedback compensation, so as to solve the signal jitter caused by environmental interference and realize the restoration of high-quality target image. The calibration method of the interference imaging device based on phase feedback compensation quasi-real-time calibration provided by the embodiment detects the interference signal in the environment when the calibration light source 14 is turned on, and uses the phase feedback compensation method for compensation, effectively solves the interference signal jitter caused by environmental interference, realizes stable measurement of the interference signal, and completes the restoration of high-quality target image.

[0100] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. The computer readable storage medium includes a magnetic disk, an optical disk, a read-only memory or a random access memory.

[0101] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.​

Claims

1. An interferometric imaging device with phase feedback compensation and quasi-real-time calibration, characterized in that, The calibration device includes an X-direction optical path, a Y-direction optical path, a controller, and a linear displacement stage; The X-direction optical path and the Y-direction optical path have the same structure, and both include two parallel coupling lenses, an interference component and a photoelectric detection component arranged in sequence along the incident direction of the light. The linear displacement stage is cross-shaped; the four coupling lenses of the X-direction optical path and the Y-direction optical path are fixed by the linear displacement stage and are evenly arranged around the center point of the cross-shaped linear displacement stage. The interference component receives the light beams output from two parallel coupled lenses and modulates the phase of the beams to cause them to interfere, outputting an interference light signal to the photodetector component; the photodetector component converts the interference light signal into an interference electrical signal. The controller is used to send control signals to the interferometer to control the phase modulation of the interferometer, and to receive the interferometric electrical signals output by the photoelectric detection component.

2. The interferometric imaging device according to claim 1, characterized in that, The interference assembly, along the incident direction of the light, includes, in sequence, a beam splitter assembly, a phase shifter group, and a 2×1 fiber coupler; The phase shifter group includes a main phase shifter and a sub-phase shifter; The photoelectric detection assembly includes first to third photoelectric detectors; The beam splitting assembly includes two beam splitting devices, each corresponding to a coupling lens. The beam output from the corresponding coupling lens is split into an interference sub-beam and an independent sub-beam. The independent sub-beams output by the two beam splitting devices are respectively output to the second and third photodetectors. The interference sub-beams output by the two beam splitting devices are respectively output to the main phase shifter and the sub-phase shifter. The main phase shifter and the sub-phase shifter input the phase-shifted beam into a 2×1 fiber coupler, and the 2×1 fiber coupler outputs the interference light signal to the first photodetector.

3. The interferometric imaging device according to claim 2, characterized in that, The main phase shifter is a piezoelectric ceramic phase shifter; the piezoelectric ceramic phase shifter receives the output voltage signal from the controller and outputs the phase-shifted optical signal; the secondary phase shifter is an optical fiber phase shifter.

4. The interferometric imaging apparatus according to claim 1, characterized in that, The calibration device also includes a motion controller, multiple servo motors, and multiple lens holders, each lens holder corresponding to a coupling lens and a servo motor; the lens holders are mounted on a linear displacement stage to fix the coupling lens; the multiple servo motors drive each lens holder to move under the control of the motion controller, thereby driving the coupling lens to move along the linear displacement stage.

5. The interferometric imaging apparatus according to claim 1, characterized in that, The aperture of each coupling lens ranges from 3 to 8 mm.

6. The interferometric imaging apparatus according to claim 2, characterized in that, The beam splitting device is a 1×2 fiber coupler or an optical beam splitter.

7. The interferometric imaging apparatus according to claim 3, characterized in that, The device also includes a calibration light source; the calibration light source is located directly in front of the center of the four coupling lenses; the calibration light source is turned on or off under the action of a controller.

8. The interferometric imaging apparatus according to claim 7, characterized in that, The device also includes a signal processor connected to the controller for receiving, displaying, and processing detector component output signals sent by the controller.

9. The interferometric imaging apparatus according to claim 7, characterized in that, The device also includes an optical switch, which turns the calibration light source on or off under the action of a controller.

10. An imaging method based on the interferometric imaging apparatus according to any one of claims 1 to 9, characterized in that, The method includes steps S1-S3: S1. Turn on the calibration light source. The controller outputs a sinusoidal voltage signal to the piezoelectric ceramic phase shifter. Find the maximum value of the interference signal. The controller records the voltage signal at the maximum value of the interference signal. Turn off the calibration light source, acquire the target light source, and the controller outputs the voltage signal corresponding to the maximum value of the interference electrical signal to the piezoelectric ceramic phase shifter. Record the signal output by the photoelectric detection component. S2. Turn the calibration light source back on. The controller outputs a sinusoidally changing voltage signal to the piezoelectric ceramic phase shifter. Find the voltage signal corresponding to the interference light intensity of I1+I2, where I1 and I2 are the light intensities entering the main phase shifter and the sub-phase shifter, respectively. Record this voltage signal. Turn off the calibration light source and acquire the target light source. The controller outputs the voltage signal corresponding to the interference light intensity of I1+I2 to the piezoelectric ceramic phase shifter. Record the signal output by the photoelectric detection component. S3. Change the position of the coupling lens on the linear displacement stage multiple times to change the length of the interference baseline. Repeat steps S1-S2. The interference light and independent sub-beams under the action of the target light source are detected by the photoelectric detection component and transmitted to the controller. The controller inverts the intensity distribution of the target light source according to this until the target light source is clearly distinguishable.

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