Digital slice scanning rapid focusing system using liquid lens

Abstract

The application discloses a digital slice scanning fast focusing system adopting a liquid lens, wherein a liquid lens, a left focusing camera and a right focusing camera are installed in the optical path of a digital slice scanner; the liquid lens is installed between an objective lens and an image-taking camera; the left focusing camera and the right focusing camera are respectively installed on the left side and the right side of the image-taking camera to collect focal plane images; a computer processing device is connected with the left focusing camera and the right focusing camera respectively to obtain a focal plane signal according to the focal plane images collected by the left focusing camera or the right focusing camera; the computer processing device is connected with a constant current source driver to send the focal plane signal; and the constant current source driver is connected with the liquid lens to send different driving currents to control the liquid lens to focus. The application adds two focusing cameras (the left focusing camera and the right focusing camera) to expand the focusing FOV to quickly obtain the focal plane signal, and then controls the liquid lens to quickly adjust to the focal plane.

Description

Technical Field

[0001] This invention relates to the field of image scanning microscopy, and more specifically to a digital slice scanning fast focusing system using a liquid lens. Background Technology

[0002] A digital slide scanner is a precision instrument composed of optics, mechanics, electronics, and computers. Its working principle involves controlling a microscopic imaging system and the slide to move according to certain rules, acquiring multiple consecutive high-resolution images, and then stitching them together to generate a single high-resolution whole-slide image (also known as a virtual digital slide image). Users can save, manage, and share this high-resolution digital image, which can be freely enlarged or reduced. This application has been widely used in pathological diagnosis, teaching and training, drug research, and scientific research.

[0003] With the widespread adoption of these applications, the performance requirements for scanners are becoming increasingly demanding, especially in terms of scanning quality and speed. Obtaining high-quality images requires accurate camera focusing. However, digitizing a single slice typically involves capturing images from thousands of fields of view and stitching them together to create a complete slice image. Therefore, the focusing method is a key factor affecting scanning speed; and the accuracy of the focus directly impacts image quality.

[0004] Currently, most focusing methods used in microscopic and scanning focusing applications rely on mechanical movement to change the focal plane of the lens, while some employ piezoelectric ceramic actuators. The former suffers from mechanical errors and backlash due to friction and wear during mechanical movement, is difficult to manufacture, and generates significant noise. The latter, while offering faster response times, has limited widespread adoption in microscopes and scanners due to its short adjustment distance and high cost.

[0005] In addition, in applications using large-area array cameras for microscopy and digital scanning systems, one way to improve scanning speed is to increase the camera's frame rate and continuously scan digital slices. The former can be achieved by using a camera with a higher frame rate, while the latter depends on the speed of focusing. Summary of the Invention

[0006] To address the aforementioned deficiencies in the prior art, this invention provides a digital slice scanning fast focusing system using a liquid lens. It adds two focusing cameras (left and right focusing cameras) to expand the focusing field of view (FOV) to quickly obtain the focal plane signal, thereby controlling the liquid lens to quickly adjust to the focal plane.

[0007] The present invention adopts the following technical solution:

[0008] A digital slicing scanning rapid focusing system employing a liquid lens includes: a digital slicing scanner, a constant current source driver, and a computer processing unit; the digital slicing scanner includes an objective lens and an image acquisition camera; a liquid lens, a left focusing camera, and a right focusing camera are also installed in the optical path of the digital slicing scanner; the liquid lens is installed between the objective lens and the image acquisition camera; the left and right focusing cameras are respectively installed on the left and right sides of the image acquisition camera to acquire focal plane images; the computer processing unit is connected to the left and right focusing cameras respectively to obtain focal plane signals based on the focal plane images acquired by the left or right focusing camera; the computer processing unit is connected to the constant current source driver to send the focal plane signals; the constant current source driver is connected to the liquid lens to send different drive currents to control the liquid lens to focus.

[0009] Preferably, the aperture of the liquid lens is 5-16mm.

[0010] Preferably, the liquid lens is mounted between the infinity correction objective and the barrel lens.

[0011] Preferably, the optical path of the digital slice scanner is divided into three paths by a beam splitter: a main optical path, a left optical path, and a right optical path. The imaging camera receives the main optical path in the optical path tube and forms a digital slice image. The left focusing camera receives the left optical path in the optical path tube and forms a left focal plane image. The right focusing camera receives the right optical path in the optical path tube and forms a right focal plane image.

[0012] Preferably, the left and right focusing cameras can obtain at least one adjacent FOV outside the FOV of the imaging camera in different directions of motion. That is, the FOV obtained by the left and right focusing cameras is greater than that of the imaging camera and is ahead of the current FOV by at least one field of view, so as to obtain one or more previous focal planes.

[0013] Preferably, during continuous scanning, the left focusing camera operates in the forward direction and the right focusing camera operates in the return direction; or, the right focusing camera operates in the forward direction and the left focusing camera operates in the return direction.

[0014] Preferably, the digital slice scanner further includes a stage and a support; the stage is mounted on the X-axis; the support is mounted on the Y-axis; the objective lens, imaging camera, liquid lens, left focusing camera, and right focusing camera are mounted on the Z-axis and along the optical path on the Y-axis; the Z-axis is perpendicular to the X-axis and Y-axis respectively, and the X-axis, Y-axis, and Z-axis form an orthogonal coordinate system; during focusing using the liquid lens, the entire Z-axis is fixed, the Y-axis drives the Z-axis to move back and forth, and the X-axis moves left and right for continuous scanning.

[0015] Preferably, the digital slice scanning fast focusing system using a liquid lens further includes: a USB hub; the computer processing device, the imaging camera, the left focusing camera, the right focusing camera, and the constant current source driver are respectively connected to the USB hub via USB cables; the liquid lens is connected to the constant current source driver via a USB cable.

[0016] Preferably, the imaging camera obtains the correct focal plane, specifically including:

[0017] During continuous scanning, the digital slice scanner scans the entire object surface back and forth without interruption. The left or right focusing camera obtains two or more focal plane images of the field of view (FOV) each time and sends them to the computer processing device. The computer processing device continuously compares the previous or more focal plane signals with the current focal plane signal and sends the resulting deviation signal to the constant current source driver. The constant current source driver generates different driving currents to drive the liquid lens, thereby enabling the imaging camera to obtain the correct focal plane.

[0018] Preferably, during the scanning of the same type of digital slice, the left or right focusing camera acquires a focal plane image and sends it to a computer processing device. The computer processing device analyzes and calculates the focal plane, performs in-depth learning on its tissue structure characteristic parameters and focusing factors to obtain one or more sets of focal plane reference values, and retains them to provide a driving signal for quickly obtaining the focal plane for the next slice or the next slice.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) In this invention, an autofocus liquid lens is installed between the imaging camera and the objective lens in a digital slice scanner. This liquid lens can quickly switch between different focal lengths and has a short response time (e.g., less than 2.5ms). Combined with the image acquisition time of the imaging camera and the processing time of the computer processing device, the focal length acquisition time is much shorter than that of a mechanical focusing system. This liquid lens can be equipped with a 10-pin lockable I / O Molex connector for use with GPIO and triggers (constant current source drivers, hereinafter referred to as drivers), and can be connected to a USB hub to realize USB signal transmission. The focusing liquid lens of this invention can be easily triggered by a computer processing device, can be individually configured to suit application requirements, and instantly ensures the acquisition of a perfect clear image. In addition, this invention designs two focusing cameras (left focusing camera and right focusing camera) in the optical path of the digital slice scanner, which can obtain the previous or more field-of-view focal planes in two scanning motion directions (forward direction and return direction) in advance, providing fast focusing for continuous scanning, thereby achieving continuous scanning of the system and improving the scanning speed.

[0021] (2) The computer processing device of the present invention has a certain AI deep self-learning function. Specifically, for the same digital slice (same tissue structure), during the scanning process, through the analysis and calculation of the focal plane, it performs in-depth learning on the characteristic parameters and focusing factors of its tissue structure and obtains one or more sets of focal plane reference values, so as to provide a driving signal for quickly obtaining the focal plane in the next (or the next slice).

[0022] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0023] Figure 1 The structure of the digital slice scanner according to an embodiment of the present invention Figure 1 ;

[0024] Figure 2 The structure of the digital slice scanner according to an embodiment of the present invention Figure 2 ;

[0025] Figure 3 This is a schematic diagram of the structure of a liquid lens according to an embodiment of the present invention; wherein, (a) represents a front view; (b) represents a cross-sectional view (AA); and (c) represents a perspective view.

[0026] Figure 4 This is a schematic diagram of the field of view (FOV) of the imaging camera and the focusing camera according to an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram showing the connections between the components of the digital slice scanning fast focusing system according to an embodiment of the present invention;

[0028] Figure 6 This is a diagram showing the correspondence between different focal plane signals and driving currents in an embodiment of the present invention;

[0029] Figure 7 This is a circuit diagram of the LC low-pass filter in the constant current source driver according to an embodiment of the present invention;

[0030] Figure 8 The stabilization time of the liquid lens in this embodiment of the invention after adding an LC filter;

[0031] Figure labels: 10, Digital slice scanner; 101, Imaging camera; 102, Left focusing camera; 1021, Output port of the left focusing camera; 103, Right focusing camera; 1031, Output port of the right focusing camera; 104, Liquid lens; 1041, Input port of the liquid lens; 105, Objective lens; 106, Digital slice; 107, Stage; 108, Support; 109, Optical path diameter; 20, Computer processing unit; 30, Constant current source driver; 40, USB hub. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," "insertion," "contact," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] See Figure 1 , 2 and Figure 5 As shown, a digital slicing scanning fast focusing system employing a liquid lens includes: a digital slicing scanner 10, a constant current source driver 30, and a computer processing unit 20; the digital slicing scanner 10 includes an objective lens 105 and an image acquisition camera 101; in the optical path of the digital slicing scanner 10, a liquid lens 104, a left focusing camera 102, and a right focusing camera 103 are also installed; the liquid lens 104 is installed between the objective lens 105 and the image acquisition camera 101; the left focusing camera 102 and the right focusing camera 103 are respectively installed... The left and right sides of the imaging camera 101 are used to acquire focal plane images; the computer processing device 20 is connected to the left focusing camera 102 and the right focusing camera 103 respectively to obtain focal plane signals based on the focal plane images acquired by the left focusing camera 102 or the right focusing camera 103; the computer processing device 20 is connected to the constant current source driver 30 to send the focal plane signals; the constant current source driver 30 is connected to the liquid lens 104 to send different driving currents to control the liquid lens 104 to focus.

[0036] In this embodiment, a left focusing camera 102 and a right focusing camera 103 are installed on the left and right sides of the optical path, ensuring that the digital slicing scanner 10 can continuously scan the entire object surface back and forth during continuous scanning. Furthermore, the left focusing camera 102 or the right focusing camera 103 obtains two or more focal plane images of the field of view (FOV) each time and sends them to the computer processing device 20. The computer processing device 20 continuously compares the previous or more focal plane signals with the current focal plane signal and sends the resulting deviation signal to the constant current source driver 30. The constant current source driver 30 generates different driving currents to drive the liquid lens 104, thereby enabling the imaging camera 101 to obtain the correct focal plane.

[0037] The principle of the liquid lens 104 is as follows: it consists of a container and an elastic polymer film covering it, filled with an optical fluid. The lens's deformation (bending) is proportional to the pressure exerted on the fluid. The lens has an electromagnetic actuator to apply this pressure. Therefore, the lens's focal length is controlled by the current flowing through the electromagnetic actuator coil. More precisely, it is a new type of optical element that dynamically adjusts the lens's refractive index or changes its own curvature to change the focal length. Because it has no moving parts, it is called a solid-state AF system.

[0038] The advantages of the liquid lens 104 include: First, for the uncertainties of optical lenses, the purely circuit-quantifiable liquid lens 104 focuses more accurately and the optical data is more precise; second, it can achieve rapid switching between different focal lengths within milliseconds, which is undoubtedly an ideal component of an autofocus system; third, since the lens itself has no moving parts, it is more resistant to vibration and impact.

[0039] In this embodiment, the aperture of the liquid lens 104 is 5-16mm. A larger aperture is better; this embodiment uses a 10mm aperture as an example. The liquid lens 104 used in this embodiment is from Opotune. See the detailed structural diagram below. Figure 3 As shown.

[0040] Specifically, the liquid lens 104 is mounted between the infinity correction objective 105 and the barrel lens. This configuration also requires the liquid lens 104 to have an infinity focal length. By changing the current on the liquid lens 104 through the constant current source driver 30, the focal length from the imaging camera 101 to the slice can be changed.

[0041] The optical path of the digital slice scanner 10 is divided into three paths by a beam splitter (not shown in the figure): a main optical path, a left optical path, and a right optical path. The imaging camera 101 receives the main optical path in the optical path tube diameter 109 and forms a digital slice image. The left focusing camera 102 receives the left optical path in the optical path tube diameter 109 and forms a left focal plane image. The right focusing camera 103 receives the right optical path in the optical path tube diameter 109 and forms a right focal plane image.

[0042] See Figure 4 As shown, the left focusing camera 102 and the right focusing camera 103 can obtain at least one adjacent FOV outside the FOV of the image capturing camera 101 in different directions of motion. That is, the FOV obtained by the left focusing camera 102 and the right focusing camera 103 is greater than that of the image capturing camera 101 and is ahead of the current FOV by at least one field of view, so as to obtain one or more previous focal planes.

[0043] Specifically, during continuous scanning, the left focusing camera 102 operates in the forward direction and the right focusing camera 103 operates in the return direction; or, the right focusing camera 103 operates in the forward direction and the left focusing camera 102 operates in the return direction, that is, obtaining focal lengths in different directions during continuous back-and-forth scanning, thereby ensuring the correctness of continuous scanning focusing.

[0044] Furthermore, the digital slice scanner 10 also includes a stage 107 and a support 108; the stage 107 is mounted on the X-axis; the support 108 is mounted on the Y-axis; the objective lens 105, the imaging camera 101, the liquid lens 104, the left focusing camera 102, and the right focusing camera 103 are mounted on the Z-axis, and are mounted on the Y-axis along with the optical path; the Z-axis is perpendicular to the X-axis and Y-axis respectively, and the X-axis, Y-axis, and Z-axis form an orthogonal coordinate system; during focusing using the liquid lens 104, the entire Z-axis is fixed and no mechanical device moves, while the Y-axis drives the Z-axis to move back and forth. In addition, the Z-axis can be fixed, and continuous scanning can be performed by moving left and right along the X-axis.

[0045] See Figure 5 As shown, the digital slice scanning fast focusing system using a liquid lens further includes: a USB hub 40; the computer processing device 20, the image camera 101, the left focusing camera 102, the right focusing camera 103, and the constant current source driver 30 are respectively connected to the USB hub 40 via USB cables; the liquid lens 104 is connected to the constant current source driver 30 via a USB cable.

[0046] Specifically, the output ports 1021 of the left focusing camera and 1031 of the right focusing camera are connected to the computer processing device 20. The USB 3.0 input port (or 2.0) of the constant current source driver 30 is connected to a USB hub 40 and then to the computer processing device 20. The output port of the constant current source driver 30 is connected to the input port 1041 of the liquid lens via a USB cable. After the focusing camera acquires the focal plane image, it is sent to the computer processing device 20. Through scanning software and calculation processing, the analyzed focal plane signal is transmitted to the input port of the constant current source driver 30 via the USB 3.0 interface of the USB hub 40. The driving current of the constant current source driver 30 is then input to the liquid lens 104 via a cable, thereby quickly changing the focal length of the optical system to achieve focusing. In this embodiment, the liquid lens 104 is connected to the constant current source driver 30 via a dedicated cable / dedicated connector, specifically a 10-pin lockable I / O Molex connector. Of course, in other embodiments, connecting lines or connectors can also be configured, which can be selected according to the specific application, as long as the liquid lens 104 and the constant current source driver 30 can communicate with each other.

[0047] For the correspondence between different focal plane signals and driving currents, please refer to [link / reference]. Figure 6 As shown in the figure, the coordinates of the driving current signal and the coordinates of the focal plane change direction are placed together. (From...) Figure 6 It can be seen that the driving current is proportional to the focal plane signal. Setting the driving current to a certain initial value E, the optical system is adjusted so that the focal plane is at its lowest point M in the opposite direction; when the driving current is at its maximum value Q, the focal plane is at its highest point N in the positive direction; when the driving current is at point P, the focal plane is at the center position O.

[0048] Furthermore, in this embodiment, during the scanning process of the same digital slice, the left focusing camera 102 or the right focusing camera 103 acquires a focal plane image and sends it to the computer processing device 20. The computer processing device 20 analyzes and calculates the focal plane, performs in-depth learning on its tissue structure characteristic parameters and focusing factors to obtain one or more sets of focal plane reference values, and retains them to provide a driving signal for quickly obtaining the focal plane for the next slice or the next slice. Specifically, the left focusing camera 102 and the right focusing camera 103 acquire focal plane images of the sliced ​​sample, send them to the application software of the computer processing device 20 to analyze the images, calculate the focusing curve of the image, then fit and obtain the peak value of the focusing curve, and adjust the Z-axis to the reference line position according to the correspondence between the peak value obtained by calibration and the Z-axis, thus completing the focusing process of the focusing camera.

[0049] In summary, based on the design requirements of the optical system and the optical characteristics of the liquid lens 104, this embodiment first installs the liquid lens 104 in an optical path with (including) an infinity focal length; secondly, to achieve continuous back-and-forth scanning and focusing of a certain area of ​​the digital slice, two beams are split in the main optical path for use by the left and right focusing cameras 103; the entire optical path system comprises an image camera 101, two focusing cameras, the liquid lens 104, an objective lens 105, and other optical components. Furthermore, an illumination device is installed, which serves as the light source for the digital slice 106. The objective lens 105 is used to observe the illuminated portion of the digital slice 106; the constant current source driver 30, connected to the computer processing unit 20, is connected to the liquid lens 104 via a cable.

[0050] The control process of the digital slice scanning fast focusing system using a liquid lens in this embodiment is as follows:

[0051] 1) Place the sliced ​​sample on the stage of the system, turn on the illumination device, and the focusing cameras on the Z-axis (left and right focusing cameras) acquire at least one focal plane image. This image is sent to the computer processing unit, where application software calculates and generates a focal plane signal. This signal is then transmitted via USB to a constant current source driver, which converts it into a proportional current. This current drives the liquid lens to acquire the calculated focal plane, which matches the focal plane signal. The entire focusing process is very short; once the liquid lens receives the focal plane drive signal, focusing can be completed in only 3-5 ms.

[0052] 2) Assuming continuous scanning begins from back to front along the Y-axis, as the imaging camera acquires the first focal plane, the left focusing camera acquires two FOV (Field of View) focal plane signals. The next focal plane signal is then provided to the imaging camera to obtain the focal plane for the next image. After the imaging camera completes its current image acquisition, it moves forward one FOV along the Y-axis. The focal plane of this FOV has already been obtained within the FOV of the previous focusing camera. Therefore, the imaging camera can continuously acquire the focal plane of the next FOV. This process repeats continuously, completing the process of pre-focusing and acquiring the focal plane.

[0053] 3) When the Y-axis moves to the interface set by the software, the X-axis moves one FOV to the left (or right), and the Y-axis movement will change direction, that is, the Y-axis movement direction will continuously scan from front to back. At this time, due to the change in direction, the right focusing camera will work to complete the pre-focusing task. The system working process is the same as in 2) above, until the scanning area set by the software is completed.

[0054] This embodiment utilizes a liquid lens focusing device, eliminating the focusing section and stepper motor of the scanning system, thus making the optical axis lighter. Throughout the scanning process, system vibration is reduced, significantly shortening the system stabilization time. This also improves image quality.

[0055] In addition, to improve the overall system stability, the constant current source driver was also improved; for details, see [link to relevant documentation]. Figure 6 As shown, an LC low-pass filter was added to make the rise time of the drive current consistent with the settling time of the liquid lens.

[0056] Specifically, the impedance of the LC low-pass filter should be designed to be equal to the impedance of the selected liquid lens. Typically, the rise time of the constant current source is 2-3 ms, and the settling time of the liquid lens is 5 ms. Through calculations and multiple tests, it has been shown that adding an LC low-pass filter can make the constant current source drive time consistent with the settling time of the liquid lens. See [link to relevant documentation]. Figure 7 The figure shows the stabilization time of the liquid lens after adding an LC filter. As can be seen from the figure, the liquid lens achieves over 90% stability in just about 5 seconds.

[0057] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A digital slide scanning fast focusing system with liquid lens, characterized in that, The application relates to a digital slice scanner, a constant current source driver and a computer processing device. The digital slice scanner comprises an objective lens and an image-taking camera. In the light path of the digital slice scanner, a liquid lens, a left focusing camera and a right focusing camera are further arranged; the liquid lens is arranged between the objective lens and the image-taking camera; the left focusing camera and the right focusing camera are arranged on the left side and the right side of the image-taking camera respectively to collect focal plane images; The computer processing device is connected with the left focusing camera and the right focusing camera respectively to obtain a focal plane signal according to the focal plane image collected by the left focusing camera or the right focusing camera; the computer processing device is connected with the constant current source driver to send the focal plane signal; and the constant current source driver is connected with the liquid lens to send different driving currents to control the liquid lens to focus. The light path of the digital slice scanner is divided into three paths, i.e. a main light path, a left light path and a right light path, by a light splitting device; the image-taking camera receives the main light path in the light path tube diameter and forms a digital slice image; the left focusing camera receives the left light path in the light path tube diameter and forms a left focal plane image; and the right focusing camera receives the right light path in the light path tube diameter and forms a right focal plane image; the left focusing camera and the right focusing camera can obtain a FOV larger than that of the image-taking camera and at least one field of view ahead of the current FOV in different motion directions to obtain one or more previous focal planes; the left focusing camera or the right focusing camera sends the focal plane image of two or more fields of view FOV obtained each time to the computer processing device, and the computer processing device compares the previous focal plane signal with the current focal plane signal without interruption and sends a deviation signal generated to the constant current source driver. The light passing aperture of the liquid lens is 5-16 mm.

2. The digital slice scanning rapid focusing system with liquid lens according to claim 1, wherein, The liquid lens is arranged between an infinite distance correction objective lens and a lens barrel.

3. The digital slice scanning rapid focusing system with liquid lens according to claim 1, wherein, In the continuous scanning process of the digital slice scanner, the left focusing camera works in the advancing direction, and the right focusing camera works in the returning direction; or the right focusing camera works in the advancing direction, and the left focusing camera works in the returning direction.

4. The digital slice scanning rapid focusing system with liquid lens according to claim 1, wherein, The digital slice scanner further comprises a sample stage and a support; the sample stage is arranged on the X axis; the support is arranged on the Y axis; the objective lens, the image-taking camera, the liquid lens, the left focusing camera and the right focusing camera are arranged on the Z axis and are arranged on the Y axis in the same light path; the Z axis is perpendicular to the X axis and the Y axis respectively, and the X axis, the Y axis and the Z axis form an orthogonal coordinate system; in the focusing process of the liquid lens, the whole Z axis is fixed, the Z axis is driven to move forward and backward by the Y axis, and continuous scanning is carried out by moving left and right with the X axis.

5. The digital slice scanning rapid focusing system with liquid lens according to claim 1, wherein, The application further relates to a USB hub.

6. The digital slice scanning rapid focusing system with liquid lens according to claim 1, characterized in that, The computer processing device, the image-taking camera, the left focusing camera, the right focusing camera and the constant current source driver are connected with the USB hub through USB lines respectively. The liquid lens is connected with the constant current source driver. The image-taking camera obtains a correct focal plane, and the method comprises the following steps: ​ 7. The digital slice scanning rapid focusing system with liquid lens according to claim 1, wherein, ​ The digital slice scanner scans the whole object surface back and forth in a continuous scanning process. The left or right focusing camera gets two or more field of view (FOV) images each time and sends them to the computer processing device. The computer processing device compares the previous one or more focal plane signals with the current focal plane signal and sends the deviation signal to the constant current source driver. The constant current source driver generates different driving currents to drive the liquid lens, so that the imaging camera gets the correct focal plane.

8. The digital slice scanning rapid focusing system with liquid lens according to claim 1, wherein, In the scanning process of the same digital slice, the left or right focusing camera collects the focal plane image and sends it to the computer processing device. The computer processing device analyzes and calculates the focal plane, deeply learns the characteristic parameters and focusing factors of the tissue structure to obtain one or more sets of focal plane reference values, and retains them to provide driving signals for the next slice or the next time.

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