Large-view-field frequency domain optical coherence tomography imaging device based on piezoelectric ceramics and detection method of large-view-field frequency domain optical coherence tomography imaging device

Abstract

The invention provides a large-view-field frequency domain optical coherence tomography device based on piezoelectric ceramics and a detection method thereof. The large-view-field frequency domain optical coherence tomography device comprises a light source, a linear array camera, a computer, a beam splitter, a reference arm, a sample arm and a detection arm. The reference arm is composed of a first collimating lens and a reflector, piezoelectric ceramics are arranged on one side of the reflector and connected with a computer, the sample arm is composed of a second collimating lens, a scanning galvanometer and a first focusing lens, an eyeball to be detected is arranged on one side of the first focusing lens, and the detection arm is composed of a third collimating lens, a grating and a second focusing lens. The linear array camera is connected with the computer, a first interface of the beam splitter is connected with the light source, a second interface of the beam splitter is connected with the detection arm, a third interface of the beam splitter is connected with the reference arm, and a fourth interface of the beam splitter is connected with the sample arm. Large-view-field tomography can be carried out on a sample with a flat internal structure, and the requirement for a sample with a curvature in the internal structure can also be met.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging, and in particular to a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics and a detection method thereof. Background Art

[0002] Optical Coherence Tomography (OCT) is a non-invasive, non-contact imaging technology with micron-level resolution. Frequency domain optical coherence tomography (SD-OCT) is the second generation of OCT technology. It combines a Michelson interferometer and a spectrometer illuminated by a broadband light source. By measuring the spectrum of the interference signal and performing a fast Fourier inverse transform on the measured spectrum, the information of different longitudinal depths of the sample can be obtained without axial scanning of the sample.

[0003] The optical path difference between the detection arm and the sample arm of the traditional SD-OCT device cannot be changed, because the important reason that affects the interference effect is the optical path difference. The more consistent the optical path difference of all test points, the better the reconstruction effect. Since there are many types of samples that need to be detected and most samples have curvature on their inner surfaces, the imaging problem of the traditional SD-OCT device for curved samples is a small field of view or poor imaging quality. Therefore, being able to dynamically and accurately adjust the optical path difference between the reference arm and the sample arm to achieve large field of view imaging of samples with curvature on the inner surface has become one of the development directions of OCT. Summary of the invention

[0004] In order to solve the above problems, especially to address the deficiencies in the prior art, the present invention provides a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics and a detection method thereof that can solve the above problems.

[0005] To achieve the above purpose, the present invention adopts the following technical means:

[0006] A large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics comprises a light source, a linear array camera, a computer, a beam splitter, a reference arm, a sample arm, and a detection arm. The light source and the detection arm are connected to one side of the beam splitter, the light source is used as the original input signal, the reference arm and the sample arm are connected to the other side of the beam splitter, the beam splitter divides the input signal of the light source into two paths, one path enters the reference arm, and the other path enters the sample arm, the detection arm is used to receive interference signals between the reference arm and the sample arm, the linear array camera is used to collect images of the detection arm, and the linear array camera and the beam splitter are respectively connected to the computer for control.

[0007] A further preferred embodiment of the present invention is as follows: the beam splitter adopts a 2x2 structure, and the light beam energy is split according to a ratio of 75:25. A first interface and a second interface are provided on one side of the beam splitter, and a third interface and a fourth interface are provided on the other side. The light source is connected to the first interface as a total input end of energy, the second interface is connected to the detection arm as an output end of energy, the third interface is connected to the reference arm, and its output energy is 25% of the total input end energy, and the fourth interface is connected to the sample arm, and its output energy is 75% of the total input end energy.

[0008] A further preferred embodiment of the present invention is as follows: the reference arm comprises a first collimating lens and a reflector corresponding to the first collimating lens, the first collimating lens is connected to a beam splitter, a side of the reflector away from the first collimating lens is connected to a piezoelectric ceramic, the piezoelectric ceramic is connected to a computer, and the computer controls the expansion and contraction of the piezoelectric ceramic to cause axial displacement of the reflector.

[0009] A further preferred embodiment of the present invention is as follows: the sample arm comprises a second collimating lens, a scanning galvanometer corresponding to the second collimating lens, and a first focusing lens corresponding to the scanning galvanometer; one side of the first focusing lens is used to set the eyeball to be tested; when in use, the surface of the eyeball to be tested is located on the image focal plane of the first focusing lens.

[0010] A further preferred solution of the present invention is that the scanning galvanometer is provided with a rotating mechanism, and the rotating mechanism drives the scanning galvanometer to rotate, thereby realizing scanning switching of multiple detection positions of the eyeball to be tested.

[0011] A further preferred embodiment of the present invention is as follows: the detection arm comprises a third collimating lens, a grating corresponding to the third collimating lens, and a second focusing lens corresponding to the grating, and the photosensitive surface of the line array camera is located on the image focal plane of the second focusing lens.

[0012] A further preferred embodiment of the present invention is as follows: the grating model is a volume holographic transmission grating with 1800 lines, and the output angle of the light after the third collimating lens satisfies the incident angle of the grating.

[0013] A detection method for a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics, the detection method comprising:

[0014] The preset first detection position of the fundus of the eyeball to be tested is placed on the image focal plane of the first focusing lens in the sample arm, and the position of the reflector in the reference arm is temporarily fixed, at which time the optical path difference between the reference arm and the sample arm is zero;

[0015] The scanning galvanometer in the sample arm rotates from the first scanning position to the second scanning position, and the corresponding light signal is scanned from the preset second detection position of the fundus of the eyeball to be tested to the preset third detection position, and the detection arm transmits the interference signal to the computer, and the computer can calculate the drift amount of the central main maximum position of the interference fringe, thereby completing the first scan;

[0016] The computer controls the axial displacement of the piezoelectric ceramic by interfering with the drift of the central main maximum position. When performing the second scan, the scanning galvanometer in the sample arm rotates from the first scanning position to the second scanning position again. While the scanning galvanometer rotates, the computer controls the expansion and contraction of the piezoelectric ceramic to cause the reflector to undergo axial displacement. Therefore, the reflector in the reference arm is displaced to the second reference position, thereby completing the second scan.

[0017] Among them, the first detection position is located in the middle of the second detection position and the third detection position; the first scanning position and the second scanning position of the scanning galvanometer correspond to the second detection position and the third detection position of the eyeball to be tested respectively.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention fixes the piezoelectric ceramic to the rear surface of the reflector in the reference arm, uses a computer to control the axial movement of the piezoelectric ceramic, and further realizes dynamic control of the optical path of the reference arm, so that it can not only perform large-field tomographic imaging on samples with flat internal tissues, but also meet the requirements for samples with curved internal surfaces, making the device more versatile. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of an eyeball to be tested in a large-field frequency-domain optical coherence tomography device based on piezoelectric ceramics according to the present invention;

[0022] Figure 3 A schematic diagram of the main maximum position of interference fringes in a large-field frequency-domain optical coherence tomography device based on piezoelectric ceramics according to the present invention;

[0023] Figure 4 This is a schematic structural diagram of a beam splitter in a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to the present invention;

[0024] Figure 5 This is a schematic structural diagram of a detection arm in a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to the present invention;

[0025] Reference numerals:

[0026] Eyeball to be tested 1, light source 2, linear array camera 3, computer 4, beam splitter 5, reference arm 6, sample arm 7, detection arm 8, first detection position 100, second detection position 101, third detection position 102, first interface 501, second interface 502, third interface 503, fourth interface 504, first collimating lens 601, reflector 602, piezoelectric ceramic 603, second reference position 6021, second collimating lens 701, scanning galvanometer 702, first focusing lens 703, first scanning position 7021, second scanning position 7022, third collimating lens 801, grating 802, second focusing lens 803. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings:

[0028] Example 1

[0029] like Figure 1 As shown, a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics includes a light source 2, a linear array camera 3, a computer 4, a beam splitter 5, a reference arm 6, a sample arm 7, and a detection arm 8. The light source 2 and the detection arm 8 are connected to one side of the beam splitter 5, and the light source 2 serves as the original input signal. The reference arm 6 and the sample arm 7 are connected to the other side of the beam splitter 5. The beam splitter 5 divides the input signal of the light source 2 into two paths, one path enters the reference arm 6, and the other path enters the sample arm 7. The detection arm 8 is used to receive the interference signal between the reference arm 6 and the sample arm 7. The linear array camera 3 is used to collect the image of the detection arm 8. The linear array camera 3 and the beam splitter 5 are respectively controlled and connected to the computer 4.

[0030] like Figure 1 and Figure 4 As shown, the beam splitter 5 adopts a 2x2 structure, and the light beam energy is split according to 75:25. A first interface 501 and a second interface 502 are provided on one side of the beam splitter 5, and a third interface 503 and a fourth interface 504 are provided on the other side. The light source 2 is connected to the first interface 501 as the total input end of energy, the second interface 502 is connected to the detection arm 8 as the output end of energy, the third interface 503 is connected to the reference arm 6, and its output energy is 25% of the total input end energy, and the fourth interface 504 is connected to the sample arm 7, and its output energy is 75% of the total input end energy.

[0031] like Figure 1-Figure 2As shown, since the reflectivity of the eyeball in the sample arm 7 is lower than that of the plane mirror, more energy is input into the sample arm 7 and lower energy is input into the reference arm 6. When detecting the reflected light, the light intensity ratio can be approximately close to 1:1, and the interference effect is obvious, which is beneficial to improving the imaging quality of the system. The signal of the light source 2 is divided into two paths and enters the reference arm 6 and the sample arm 7 respectively, ensuring the basic conditions for signal spatial interference. The detection arm 8 is used to receive the interference signal.

[0032] The reference arm 6 includes a first collimating lens 601 and a reflector 602 corresponding to the first collimating lens 601. The first collimating lens 601 is connected to the beam splitter 5. The side of the reflector 602 away from the first collimating lens 601 is connected to a piezoelectric ceramic 603. The piezoelectric ceramic 603 is connected to a computer 4. The computer 4 can control the piezoelectric ceramic 603 to move axially, and the reflector 602 can move axially to a second reference position 6021.

[0033] Due to the properties of the piezoelectric ceramic 603 itself, when stimulated by an external electric field, the piezoelectric ceramic 603 will undergo axial expansion and contraction, so the computer 4 can control the piezoelectric ceramic 603 to move axially. Because the piezoelectric ceramic 603 is fixedly connected to the reflector 602, the reflector 602 can move axially to the second reference position 6021. Since the optical path of the sample arm 7 is a variable as the scanning galvanometer 702 rotates, the computer 4 controls the movement of the piezoelectric ceramic 602 through the optical path difference between the reference arm 6 and the sample arm 7, so that when the optical path of the sample arm 7 changes, the reference arm 6 and the sample arm 7 always maintain the same optical path difference.

[0034] The sample arm 7 includes a second collimating lens 701, a scanning galvanometer 702 corresponding to the second collimating lens 701, and a first focusing lens 703 corresponding to the scanning galvanometer 702. An eyeball 1 to be tested is provided on one side of the first focusing lens 703, and the surface of the eyeball 1 to be tested is located on the image focal plane of the first focusing lens 703.

[0035] like Figure 2 As shown, the eyeball 1 to be tested is a pig eye, and the fundus of the eyeball 1 to be tested includes a first detection position 100 , a second detection position 101 and a third detection position 102 . The first detection position 100 is located at the center of the second detection position 101 and the third detection position 102 .

[0036] The detection positions are imaginary points, only for more clearly expressing the working principle of the system. The first detection position 100 is located in the center of the second detection position 101 and the third detection position 102. The above-mentioned detection positions of the eyeball are all choroid positions of the eyeball, wherein the choroid (fundus) detection position of the eyeball adopts a symmetrical structure. However, the device is not limited to detecting symmetrical positions. If a symmetrical position is adopted, the control signal of the computer 4 to the piezoelectric ceramic 603 is also symmetrical, which is beneficial to the integrity of the fundus detection imaging of the eyeball.

[0037] like Figure 1-3 As shown, the scanning galvanometer 702 is a rotating mechanism, and the scanning galvanometer 702 can rotate from a first scanning position 7021 to a second scanning position 7022. The first scanning position 7021 and the second scanning position 7022 of the scanning galvanometer 702 correspond to the second detection position 101 and the third detection position 102 of the eyeball 1 to be tested, respectively.

[0038] The scanning galvanometer 702 is a rotating mechanism. The scanning galvanometer 702 can rotate from a first scanning position 7021 to a second scanning position 7022, thereby realizing a complete detection of the fundus of the eyeball. The first scanning position 7021 and the second scanning position 7022 of the scanning galvanometer 702 correspond to the second detection position 101 and the third detection position 102 of the eyeball 1 to be detected, respectively, and also correspond to the position z of the central main maximum, respectively. -1 , z1, since the second detection position 101 is symmetrical to the third detection position 102, when the reflector 602 moves to the position of the second reflector 6021, the sample arm 7 and the sample arm 6 are both at the position of equal optical path difference.

[0039] like Figure 1 and Figure 5 As shown, the detection arm 8 includes a third collimating lens 801 , a grating 802 corresponding to the third collimating lens 801 , and a second focusing lens 803 corresponding to the grating 802 . The photosensitive surface of the line array camera 3 is located on the image focal plane of the second focusing lens 803 .

[0040] The grating 802 model is a volume holographic transmission grating with 1800 lines, and the output angle of the light after the third collimating lens 801 meets the incident angle of the grating 802 .

[0041] The position of the third collimating lens 801 satisfies the incident angle condition of the grating 802. The light incident angle condition of the grating 802 is closely related to the type of the grating 802 and the number of lines on the grating surface. The grating 802 model is a volume holographic transmission grating with 1800 lines. As long as the output angle of the output light of the second interface 502 after passing through the third collimating lens 801, that is, α, satisfies the incident angle condition of the grating 802, the diffraction effect of the grating is guaranteed to be the best, thereby improving the resolution of the detection end and the imaging quality of the system.

[0042] Example 2

[0043] like Figure 1-5 As shown, a large-field frequency-domain optical coherence tomography device based on piezoelectric ceramics is characterized in that it includes a light source 2, a linear array camera 3, a computer 4, a beam splitter 5, a reference arm 6, a sample arm 7, and a detection arm 8. The light source 2 and the detection arm 8 are connected to one side of the beam splitter 5, and the light source 2 is used as the original input signal. The reference arm 6 and the sample arm 7 are connected to the other side of the beam splitter 5. The beam splitter 5 divides the input signal of the light source 2 into two paths, one path enters the reference arm 6, and the other path enters the sample arm 7. The detection arm 8 is used to receive the interference signal between the reference arm 6 and the sample arm 7. The linear array camera 3 is used to collect the image of the detection arm 8. The linear array camera 3 and the beam splitter 5 are respectively connected to the computer 4 for control;

[0044] The beam splitter 5 is provided with a first interface 501 and a second interface 502 on one side, and a third interface 503 and a fourth interface 504 on the other side. The light source 2 is connected to the first interface 501 as the total input end of energy, the second interface 502 is connected to the detection arm 8 as the output end of energy, the third interface 503 is connected to the reference arm 6, and its output energy is 25% of the total input end energy, and the fourth interface 504 is connected to the sample arm 7, and its output energy is 75% of the total input end energy;

[0045] The reference arm 6 includes a first collimating lens 601 and a reflector 602 corresponding to the first collimating lens 601. The first collimating lens 601 is connected to the beam splitter 5. The side of the reflector 602 away from the first collimating lens 601 is connected to a piezoelectric ceramic 603. The piezoelectric ceramic 603 is connected to a computer 4. The computer 4 can control the piezoelectric ceramic 603 to move axially, and the reflector 602 can move axially to a second reference position 6021.

[0046] The sample arm 7 includes a second collimating lens 701, a scanning galvanometer 702 corresponding to the second collimating lens 701, and a first focusing lens 703 corresponding to the scanning galvanometer 702. An eyeball 1 to be tested is disposed on one side of the first focusing lens 703, and a surface of the eyeball 1 to be tested is located on the image focal plane of the first focusing lens 703.

[0047] The fundus of the eyeball 1 to be tested includes a first detection position 100, a second detection position 101 and a third detection position 102, and the first detection position 100 is located at the center of the second detection position 101 and the third detection position 102;

[0048] The scanning galvanometer 702 is a rotating mechanism, and the scanning galvanometer 702 can rotate from a first scanning position 7021 to a second scanning position 7022. The first scanning position 7021 and the second scanning position 7022 of the scanning galvanometer 702 correspond to the second detection position 101 and the third detection position 102 of the eyeball 1 to be tested, respectively.

[0049] The detection arm 8 includes a third collimating lens 801 , a grating 802 corresponding to the third collimating lens 801 , and a second focusing lens 803 corresponding to the grating 802 . The photosensitive surface of the line array camera 3 is located on the image focal plane of the second focusing lens 803 .

[0050] Example 3

[0051] Embodiment 3 is the detection method of embodiment 2, such as Figure 1-5 As shown, a detection method for a large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics, the detection method comprising:

[0052] Step 1: Place the first detection position 100 of the fundus of the eyeball 1 to be tested on the image focal plane of the first focusing lens 703 in the sample arm 7, and temporarily fix the position of the reflector 602 in the reference arm 6. At this time, the optical path difference between the reference arm 6 and the sample arm 7 is zero;

[0053] Step 2: The scanning galvanometer 702 in the sample arm 7 rotates from the first scanning position 7021 to the second scanning position 7022, and the corresponding optical signal is scanned from the second detection position 101 of the fundus of the eyeball 1 to be tested to the third detection position 102. The detection arm 8 transmits the interference signal to the computer 4, and the computer 4 can calculate the drift amount of the central main maximum position of the interference fringe, thus completing the first scan;

[0054] Step 3: Computer 4 controls the axial displacement of piezoelectric ceramic 603 by interfering with the drift of the central main maximum position. When performing the second scan, scanning galvanometer 702 in sample arm 7 rotates from the first scanning position 7021 to the second scanning position 7022 again. While scanning galvanometer 702 rotates, computer 4 controls the expansion and contraction of piezoelectric ceramic 603 to cause axial displacement of reflector 602. Therefore, reflector 602 in reference arm 6 moves to the second reference position 6021. By changing the position of reflector 602 in real time, reference arm 6 and sample arm 7 maintain equal optical path difference. Detection arm 8 transmits interference signal to computer 4. Computer 4 restores the intensity information of light in the depth domain according to the interference signal, draws its image after slight wave processing, and thus completes the second scan, and finally completes the large field imaging of choroid of eyeball 1 to be tested.

[0055] Combination Figure 1-Figure 5The signal of the light source 2 of the present invention is divided into two paths through the beam splitter 5, one path enters the reference arm 6, and the other path enters the sample arm 7. The detection arm 8 is used to receive the interference signal. The length of the optical fiber used in the device is relatively short, so the transmission loss of the optical fiber for the light signal can be ignored. The device completes the large-field imaging of the sample by scanning the choroid of the eyeball 1 to be tested twice. In the first scanning, the interference signal is analyzed by the computer 4 to determine the three different positions of the eyeball 1 to be tested: the positions of the interference central main maximum corresponding to the first detection position 100, the second detection position 101 and the third detection position 102 are z0, z1 and z2, respectively. -1 , z1, so when performing the second scan, the computer 4 dynamically adjusts the position of the reflector 602 by the different interference central main maximum positions corresponding to different detection positions to ensure that the optical path difference between the reference arm 6 and the sample arm 7 is zero. The device uses a computer to control the axial movement of the piezoelectric ceramics and dynamically controls the optical path of the reference arm 6 to achieve large-field tomographic imaging of samples with curved surfaces inside, making the device more versatile.

[0056] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics, characterized in that: The invention comprises a light source (2), a linear array camera (3), a computer (4), a beam splitter (5), a reference arm (6), a sample arm (7), and a detection arm (8). The light source (2) and the detection arm (8) are connected to one side of the beam splitter (5). The light source (2) serves as the original input signal. The reference arm (6) and the sample arm (7) are connected to the other side of the beam splitter (5). The beam splitter (5) divides the input signal of the light source (2) into two paths, one path entering the reference arm (6) and the other path entering the sample arm (7). The detection arm (8) is used to receive the interference signal between the reference arm (6) and the sample arm (7). The linear array camera (3) is used to collect the image of the detection arm (8). The linear array camera (3) and the beam splitter (5) are respectively connected to the computer (4) for control.

2. The large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to claim 1, characterized in that: The beam splitter (5) adopts a 2x2 structure, and the light beam energy is split according to 75:

25. A first interface (501) and a second interface (502) are provided on one side of the beam splitter (5), and a third interface (503) and a fourth interface (504) are provided on the other side. The light source (2) is connected to the first interface (501) as the total input end of energy, the second interface (502) is connected to the detection arm (8) as the output end of energy, the third interface (503) is connected to the reference arm (6), and its output energy is 25% of the total input end energy, and the fourth interface (504) is connected to the sample arm (7), and its output energy is 75% of the total input end energy.

3. The large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to claim 2, characterized in that: The reference arm (6) comprises a first collimating lens (601) and a reflector (602) corresponding to the first collimating lens (601); the first collimating lens (601) is connected to a beam splitter (5); a side of the reflector (602) away from the first collimating lens (601) is connected to a piezoelectric ceramic (603); the piezoelectric ceramic (603) is connected to a computer (4); and the computer (4) controls the expansion and contraction of the piezoelectric ceramic (603) to cause an axial displacement of the reflector (602).

4. The large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to claim 3, characterized in that: The sample arm (7) comprises a second collimating lens (701), a scanning galvanometer (702) corresponding to the second collimating lens (701), and a first focusing lens (703) corresponding to the scanning galvanometer (702); one side of the first focusing lens (703) is used to set the eyeball (1) to be tested; when in use, the surface of the eyeball (1) to be tested is located on the image-side focal plane of the first focusing lens (703).

5. The large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to claim 4, characterized in that: The scanning galvanometer (702) is provided with a rotation mechanism, and the rotation mechanism drives the scanning galvanometer (702) to rotate, thereby realizing scanning switching of multiple detection positions of the eyeball (1) to be tested.

6. The large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to claim 5, characterized in that: The detection arm (8) comprises a third collimating lens (801), a grating (802) corresponding to the third collimating lens (801), and a second focusing lens (803) corresponding to the grating (802); the light-sensitive surface of the line array camera (3) is located on the image-side focal plane of the second focusing lens (803).

7. The large-field-of-view frequency-domain optical coherence tomography device based on piezoelectric ceramics according to claim 6, characterized in that: The grating (802) is a volume holographic transmission grating with 1800 lines, and the output angle of the light after the third collimating lens (801) satisfies the incident angle of the grating (802).

8. A detection method for a large field of view frequency domain optical coherence tomography device based on piezoelectric ceramics according to claim 7, characterized in that: The detection method comprises: A first detection position (100) preset at the fundus of the eyeball (1) to be tested is placed on the image focal plane of the first focusing lens (703) in the sample arm (7), and the position of the reflector (602) in the reference arm (6) is temporarily fixed, at which time the optical path difference between the reference arm (6) and the sample arm (7) is zero; The scanning galvanometer (702) in the sample arm (7) rotates from a first scanning position (7021) to a second scanning position (7022), and the corresponding optical signal is scanned from a preset second detection position (101) of the fundus of the eyeball (1) to be tested to a preset third detection position (102), and the detection arm (8) transmits the interference signal to the computer (4), and the computer (4) is able to calculate the drift amount of the central main maximum position of the interference fringe, thereby completing the first scan; The computer (4) controls the axial displacement of the piezoelectric ceramic (603) by interfering with the drift of the central main maximum position. When performing the second scan, the scanning galvanometer (702) in the sample arm (7) rotates again from the first scanning position (7021) to the second scanning position (7022). While the scanning galvanometer (702) rotates, the computer (4) controls the expansion and contraction of the piezoelectric ceramic (603) to cause the reflector (602) to undergo axial displacement. Therefore, the reflector (602) in the reference arm (6) is displaced to the second reference position (6021), thereby completing the second scan. The first detection position (100) is located in the middle of the second detection position (101) and the third detection position (102); the first scanning position (7021) and the second scanning position (7022) of the scanning galvanometer (702) respectively correspond to the second detection position (101) and the third detection position (102) of the eyeball (1) to be tested.

Images