A corneal confocal high-speed imaging misregistration distortion correction system

Abstract

The application provides a corneal confocal high-speed imaging misregistration distortion correction system, which increases a light barrier providing a position reference in a main image plane in a corneal confocal scanning imaging light path, corrects misregistration images through the position of the light barrier in the imaging process, overcomes high-speed bidirectional image misregistration distortion caused by non-ideal motion of a resonant mirror, and realizes bidirectional high-speed scanning imaging.

Description

Technical Field

[0001] The present application relates to optical detection technology, and in particular to a corneal confocal high-speed imaging misalignment and distortion correction system. Background Art

[0002] Infectious keratitis is the second most common cause of blindness in my country after cataracts, with approximately two million cases of monocular blindness caused by corneal infection each year. Patients with infectious keratitis are prone to recurrent and persistent illness, and the condition is often confused with other conditions, resulting in high misdiagnosis rates and significant treatment difficulties. Corneal confocal microscopy can obtain clear, cellular-level images of all corneal layers, enabling rapid, noninvasive diagnosis of corneal infectious diseases.

[0003] Corneal confocal imaging faces the challenge of involuntary eye movement. To overcome this, imaging speed needs to be increased. The solution is to use two specialized galvanometer mirrors: resonant galvanometers and galvanometer galvanometers. These galvanometers can rapidly scan the imaging surface in both directions, significantly improving overall imaging speed. Resonant galvanometers are yaw mechanisms that use the resonance principle for high-speed scanning. These mechanisms typically have a natural frequency. When the frequency of the external driving force matches this natural frequency, resonance occurs, enabling efficient, high-speed scanning. During this process, the angular motion of the resonant galvanometer mirror typically follows a cosine law, meaning its angular velocity varies over time, with maximum angular velocity occurring at the peaks and troughs of the cosine waveform. However, considering only the cosine waveform, theoretically, the velocities of the forward and return strokes should be the same at the same angular position (e.g., halfway from the peak to the trough and halfway from the trough to the peak). However, in actual applications, the movement of the resonant galvanometer may be affected by various factors, such as friction, damping, and nonlinear effects of the mechanical structure. These may cause certain differences in the speed of the outbound and return strokes during actual measurement. This results in the odd and even rows being misaligned when imaging using both the outbound and return strokes (the outbound stroke is the odd rows of the image, and the return stroke is the even rows of the image). At the same time, because the frequency of the resonant galvanometer also drifts during operation, the misalignment of the odd and even rows is superimposed on the nonlinear distortion inherent in the resonant galvanometer scanning, and a simple alignment algorithm cannot be used to correct this image misalignment. Summary of the Invention

[0004] In view of this, it is necessary to provide a corneal confocal high-speed imaging misalignment and distortion correction system that can correct misaligned images to address the technical defects of high-speed bidirectional image misalignment and distortion in the current corneal confocal high-speed imaging misalignment and distortion correction system.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] One of the purposes of the present application is to provide a corneal confocal high-speed imaging misalignment correction system, comprising: a laser, a beam splitter, a scanning galvanometer, a scanning lens, a primary image aperture, a tube lens, an objective lens, a pinhole lens, a pinhole, a detector, and an imaging control unit, wherein the imaging control unit is electrically connected to the laser, the detector, and the scanning galvanometer, wherein:

[0007] The illumination light beam emitted by the laser is reflected by the beam splitter and then incident on the scanning galvanometer mirror. The illumination light beam scanned by the scanning galvanometer mirror is incident on the scanning lens and then enters the tubular mirror through the main image plane aperture. The illumination light beam passing through the tubular mirror is then focused on the cornea through the objective lens. The objective lens collects the light signal from the cornea. The light signal then passes through the tubular mirror, the main image plane aperture, the scanning lens, the scanning galvanometer mirror, the beam splitter, the pinhole lens in sequence and then passes through the pinhole to be detected by the detector. The detector converts the acquired light signal into an electrical signal and transmits it to the imaging control unit. The imaging control unit receives the electrical signal and reconstructs the scanned image.

[0008] The imaging control unit controls the scanning galvanometer to perform horizontal scanning and vertical scanning to realize point scanning imaging of the corneal confocal system, and controls the position of the main image plane aperture during the scanning imaging process to correct the misaligned image.

[0009] In some embodiments, the imaging control unit drives the scanning galvanometer to scan horizontally to generate a resonance waveform, the displacement and time of which conform to the law of the cosine function, and in one cycle, it can be divided into two scanning parts: the forward scan and the return scan;

[0010] The imaging control unit drives the scanning galvanometer to scan longitudinally to generate a galvanometer waveform. When the resonance waveform completes a forward or return scan, its position switches to the position of the next row.

[0011] In some embodiments, some values ​​of the main image plane stop in the data sequence obtained by scanning imaging are characteristic intensity values ​​of the main image plane stop, and the specific process is as follows:

[0012] a) Sampling: For each data sampling, i.e., the scanning galvanometer swings for one cycle, the number of sampling points is N, and the sampling data is {s[n], n=1→N};

[0013] b) Outbound and return data segmentation: Obtain the boundary positions n1, n2, n3, n4 between the characteristic intensity value and the normal intensity value of the main image plane aperture, then the outbound data is {s[n], n=n1→n2}, and the return data is {s[n], n=

[0014] n3→n4}, at this time, the return and outbound data are ensured to have an imaging area range by the main image plane aperture.

[0015] In some embodiments, the imaging control unit controls the position of the main image plane aperture to correct the misaligned image, specifically including the following:

[0016] Perform conventional cosine nonlinear distortion correction on the outbound data and the return data respectively to obtain odd-numbered and even-numbered row image data;

[0017] The image data of the odd-numbered lines and the image data of the even-numbered lines are combined to form a complete corneal confocal image.

[0018] In some embodiments, the steps of performing conventional cosine nonlinear distortion correction on the outbound data and the return data to obtain odd-numbered and even-numbered image data specifically include:

[0019] Corresponding to the outbound path, which is the odd-numbered row of the image, the sampling point number corresponding to the pixel coordinate x is:

[0020]

[0021] pass The rounded value is Then the intensity value corresponding to the pixel coordinate x is

[0022] Corresponding to the return path, which is the even-numbered row of the image, the sampling point number corresponding to the pixel coordinate x is:

[0023]

[0024] pass The rounded value is Then the intensity value corresponding to the pixel coordinate x is

[0025] Among them: the number of pixels in a row is determined by X max , the pixel value of each row I l (x),x=1→X max ,l is the line number.

[0026] In some embodiments, an objective lens driving unit is further included, and the objective lens driving unit can drive the objective lens to move. The imaging control unit is electrically connected to the objective lens driving unit and is used to control the operation of the objective lens driving unit.

[0027] This application adopts the above technical solution, and its beneficial effects are as follows:

[0028] The corneal confocal high-speed imaging misalignment and distortion correction system provided in the present application adds an aperture that provides a position reference to the main image plane in the corneal confocal scanning imaging light path, and corrects the misaligned image through the position of the aperture during the imaging process, thereby overcoming the high-speed bidirectional image misalignment and distortion caused by the non-ideal movement of the resonant galvanometer, and realizing bidirectional high-speed scanning imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 This is a structural schematic diagram of the corneal confocal high-speed imaging misalignment and distortion correction system provided in Example 1 of the present application.

[0031] Figure 2 This is a schematic diagram of the control waveform and image of bidirectional image scanning provided in Example 1 of the present application.

[0032] Figure 3 The first embodiment of the present invention provides a method for obtaining outbound and return data based on aperture characteristics.

[0033] Figure 4 This is a flowchart of image misalignment and distortion processing based on aperture provided in Example 1 of the present invention.

[0034] Figure 5 This is the correspondence between the pixels of the outbound and return image rows and the sampling sequence provided by Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0036] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0038] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] Example 1

[0040] See also Figure 1 , which is a schematic diagram of the structure of the corneal confocal high-speed imaging misalignment correction system provided by an embodiment of the present application, includes a laser 11, a beam splitter 12, a scanning galvanometer 13, a scanning lens 14, a primary image aperture 15, a tube lens 16, an objective lens 17, a pinhole lens 18, a pinhole 19, a detector 20, and an imaging control unit 21. The following describes in detail the technical solution implemented by the system.

[0041] The laser 11 is used to provide an illumination beam and is also electrically connected to the imaging control unit 21 , which can control the illumination beam of the laser 11 .

[0042] The beam splitter 12 can reflect the illumination beam and transmit the light from the sample.

[0043] The scanning galvanometer 13 can drive the scanning light spot to traverse the sample imaging area. The scanning galvanometer 13 is also electrically connected to the imaging control unit 21, and the imaging control unit 21 can control the scanning galvanometer 13.

[0044] The scanning lens 14 can correct image distortion caused by partial scanning. The scanning lens 14 is also electrically connected to the imaging control unit 21 , and the imaging control unit 21 can control the scanning lens 14 .

[0045] The main image plane aperture 15 is used to provide a position reference during the horizontal scanning process. The position of the aperture during the imaging process is used to correct the misaligned image and achieve bidirectional high-speed scanning imaging.

[0046] It should be noted that in practice, the position of the main image plane diaphragm 15 can be adjusted manually or automatically to better correct the misaligned and distorted image; or the position of the main image plane diaphragm 15 can be adjusted by the main control unit 21 .

[0047] The tube lens 16 cooperates with the objective lens 17, which illuminates the cornea and collects signals from the cornea. The objective lens 17 is also connected to an objective lens drive unit (not shown) that drives the objective lens to move. The imaging control unit 21 is electrically connected to the objective lens drive unit and is used to control the operation of the objective lens drive unit to achieve movement of the objective lens focal plane across the full thickness of the cornea.

[0048] The detector 19 is used to receive light signals from the sample, convert them into electrical signals and provide them to the imaging control unit 21 for data acquisition.

[0049] The corneal confocal high-speed imaging misalignment correction system provided in the above embodiments of the present application works as follows:

[0050] The illumination light beam emitted by the laser 11 is reflected by the beam splitter 12 and then enters the scanning galvanometer mirror 13. The illumination light beam scanned by the scanning galvanometer mirror 13 is incident on the scanning lens 14, and then enters the tubular lens 16 through the main image plane aperture 15. The illumination light beam passing through the tubular lens 16 is then focused on the cornea through the objective lens 17. The objective lens 17 collects the light signal from the cornea. The light signal then passes through the tubular lens 16, the main image plane aperture 15, the scanning lens 14, the scanning galvanometer mirror 13, the beam splitter 12, the pinhole lens 18 in sequence, and then passes through the pinhole 19 to be detected by the detector 20. The detector 20 converts the acquired light signal into an electrical signal and transmits it to the imaging control unit 21. The imaging control unit 21 receives the electrical signal and reconstructs the scanned image.

[0051] The imaging control unit 21 controls the scanning galvanometer 13 to perform horizontal scanning and vertical scanning to realize corneal confocal system point scanning imaging, and controls the position of the main image plane aperture 15 during the scanning imaging process to correct the misaligned image.

[0052] In this embodiment, the imaging control unit 21 drives the scanning galvanometer to scan horizontally to generate a resonance waveform, whose displacement and time conform to the law of the cosine function. In one cycle, it can be divided into two scanning parts: the outbound scan and the return scan. The imaging control unit 21 drives the scanning galvanometer to scan longitudinally to generate a galvanometer waveform. When the resonance waveform completes a forward or return scan, its position switches to the position of the next row.

[0053] See also Figure 2 , which is a schematic diagram of the control waveform and image of the bidirectional image scanning provided in this embodiment, the imaging control unit 21 drives the scanning galvanometer mirror to scan longitudinally to generate the galvanometer waveform. The galvanometer mirror drives the longitudinal scanning. When the resonance waveform completes a forward (return) scan, its position switches to the position of the next row (such as Figure 2Where a represents the waveform of the bidirectional scanning process), Figure 2 Figure b (bidirectional scanning image diagram) shows the bidirectional scanning process, where the blue lines can be the image lines obtained by the point scanning imaging of the outgoing (return) process of the resonant galvanometer, and the red lines can be the image lines obtained by the point scanning imaging in the returning direction.

[0054] Furthermore, since a main image plane diaphragm 15 is added to the main image plane of the corneal confocal imaging system, some values ​​in the data sequence obtained by scanning imaging are characteristic intensity values ​​of the diaphragm (such as Figure 3 ) The process is as follows:

[0055] a) Sampling: For each data sampling, i.e., the scanning galvanometer swings for one cycle, the number of sampling points is N, and the sampling data is {s[n], n=1→N};

[0056] b) Segmentation of outbound and return data: Obtain the boundary positions n1, n2, n1, n4 of the characteristic intensity values ​​and the normal intensity values ​​of the main image plane aperture, then the outbound data is {s[n], n=n1→n2}, and the return data is {s[n], n=n3→n4}. At this time, the return and outbound data are guaranteed by the main image plane aperture to have the range of their imaging area.

[0057] Furthermore, the imaging control unit controls the position of the main image plane aperture to correct the misaligned image, specifically including the following: performing conventional cosine nonlinear distortion correction on the outbound data and the return data respectively to obtain odd-line and even-line image data; and merging the odd-line and even-line image data into a complete corneal confocal image.

[0058] Furthermore, the steps of performing conventional cosine nonlinear distortion correction on the outbound data and the return data to obtain odd-numbered and even-numbered image data specifically include:

[0059] Corresponding to the outbound path, which is the odd-numbered row of the image, the sampling point number corresponding to the pixel coordinate x is:

[0060]

[0061] pass The rounded value is Then the intensity value corresponding to the pixel coordinate x is

[0062] Corresponding to the return path, which is the even-numbered row of the image, the sampling point number corresponding to the pixel coordinate x is:

[0063]

[0064] pass The rounded value is Then the intensity value corresponding to the pixel coordinate x is

[0065] Among them: the number of pixels in a row is determined by X max , the pixel value of each row I l (x),x=1→X max ,l is the line number.

[0066] See also Figure 5 , which is the correspondence between the outbound and return image row pixels and the sampling sequence provided in this embodiment, a) is the correspondence between the outbound row image pixels and the sampling sequence, b) is the correspondence between the return row image pixels and the sampling sequence.

[0067] The corneal confocal high-speed imaging misalignment and distortion correction system provided in the present application adds an aperture that provides a position reference to the main image plane in the corneal confocal scanning imaging light path, and corrects the misaligned image through the position of the aperture during the imaging process, thereby overcoming the high-speed bidirectional image misalignment and distortion caused by the non-ideal movement of the resonant galvanometer, and realizing bidirectional high-speed scanning imaging.

[0068] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A corneal confocal high-speed imaging misalignment correction system, characterized in that: include: A laser, a beam splitter, a scanning galvanometer, a scanning lens, a primary image aperture, a tube lens, an objective lens, a pinhole lens, a pinhole, a detector, and an imaging control unit, wherein the imaging control unit is electrically connected to the laser, the detector, and the scanning galvanometer, wherein: The illumination light beam emitted by the laser is reflected by the beam splitter and then incident on the scanning galvanometer mirror. The illumination light beam scanned by the scanning galvanometer mirror is incident on the scanning lens and then enters the tubular mirror through the main image plane aperture. The illumination light beam passing through the tubular mirror is then focused on the cornea through the objective lens. The objective lens collects the light signal from the cornea. The light signal then passes through the tubular mirror, the main image plane aperture, the scanning lens, the scanning galvanometer mirror, the beam splitter, the pinhole lens in sequence and then passes through the pinhole to be detected by the detector. The detector converts the acquired light signal into an electrical signal and transmits it to the imaging control unit. The imaging control unit receives the electrical signal and reconstructs the scanned image. The imaging control unit controls the scanning galvanometer to perform horizontal scanning and vertical scanning to realize corneal confocal system point scanning imaging, and controls the position of the main image plane aperture during the scanning imaging process to correct the misaligned image; The imaging control unit controls the position of the main image plane aperture to correct the misaligned image, specifically including the following steps: performing conventional cosine nonlinear distortion correction on the outbound data and the return data to obtain odd-numbered and even-numbered lines of image data; and merging the odd-numbered and even-numbered lines of image data into a complete corneal confocal image. The steps of performing conventional cosine nonlinear distortion correction on the outbound data and the return data to obtain odd-numbered and even-numbered image data specifically include: Corresponding to the outbound path, it is the odd-numbered rows of the image, pixel coordinates The corresponding sampling point numbers are: pass The rounded value is , then the intensity value corresponding to the pixel coordinate x is ; Corresponding to the return, which is the even row of the image, pixel coordinates The corresponding sampling point numbers are: pass The rounded value is , then the intensity value corresponding to the pixel coordinate x is ; Among them: the number of pixels in a row , the pixel value of each row , is the line number.

2. The corneal confocal high-speed imaging misalignment correction system according to claim 1, characterized in that: The imaging control unit drives the scanning galvanometer to scan horizontally to generate a resonance waveform, the displacement and time of which conform to the law of the cosine function. In one cycle, the scanning waveform can be divided into two parts: the forward scan and the return scan. The imaging control unit drives the scanning galvanometer to scan longitudinally to generate a galvanometer waveform. When the resonance waveform completes a forward or return scan, its position switches to the position of the next row.

3. The corneal confocal high-speed imaging misalignment correction system according to claim 2, wherein: Part of the values ​​in the data sequence obtained by scanning imaging of the main image plane stop are characteristic intensity values ​​of the main image plane stop. The specific process is as follows: a) Sampling: For each data sampling, i.e., the scanning galvanometer swings for one cycle, the number of sampling points is , sampling data ; b) Data segmentation for the return trip: obtaining the boundary position between the characteristic intensity value and the normal intensity value of the main image plane aperture , then the outbound data is , the return data is At this time, the return and outbound data are ensured to have an imaging area range by the main image plane aperture.

4. The corneal confocal high-speed imaging misalignment correction system according to claim 1, wherein: It also includes an objective lens driving unit, which can drive the objective lens to move. The imaging control unit is electrically connected to the objective lens driving unit and is used to control the operation of the objective lens driving unit.

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