Light spot position detection method, automatic focusing method, related system and storage medium

Abstract

The invention provides a light spot position detection method, an automatic focusing method, a related system and a storage medium. A first light source is controlled to emit a first light beam to irradiate a to-be-detected sample, and a focusing sensor is controlled to receive the first light beam reflected from the to-be-detected sample; acquiring pixel data generated when the focusing sensor senses a light spot, formed on the focusing sensor, of the first light beam, and determining the center pixel position of the light spot based on the pixel data so as to determine the position of the light spot. According to the invention, the position of the light spot can be determined, so that the automatic focusing system can perform automatic focusing based on the position of the light spot, and the image definition is improved. Besides, in the invention, the light spot position is determined by using the central pixel position in the pixel data sensed by the focusing sensor, and the central pixel position can represent the central position of the light spot, so that the light spot position determination accuracy can be relatively high by determining the light spot position based on the central pixel position; therefore, the accuracy of automatic focusing and the image definition are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging, and more specifically, to a method for detecting the position of a light spot, an autofocus method, a related system, and a storage medium. Background Art

[0002] In a sequencing platform that realizes nucleic acid sequence determination based on optical microscopy imaging, when using an optical microscopy imaging system to image multiple different regions on a sequencing chip one by one, due to mechanical tolerances, external forces, or other influences, the defocus amount (the distance from the focal plane) of each region is different. After the optical microscopy imaging system focuses on each region one by one, for example, by manually adjusting the microscopy imaging system and / or the sequencing chip to make the region to be measured located on its focal plane, a clear image of each region can be obtained. This operation method is cumbersome and time-consuming and laborious. Therefore, how to achieve autofocus is a problem worthy of attention. Summary of the Invention

[0003] In view of this, the present invention provides a method for detecting the position of a light spot, an autofocus method, a related system, and a storage medium, aiming to solve at least one of the above problems to at least a certain extent.

[0004] On the one hand, the present invention provides a method for detecting the position of a light spot for an autofocus system, and the autofocus system includes a first light source and a focus sensor;

[0005] The method for detecting the position of the light spot includes:

[0006] Controlling the first light source to emit a first light beam to irradiate the sample to be measured;

[0007] Controlling the focus sensor to receive the first light beam reflected from the sample to be measured;

[0008] Obtaining pixel data generated by the focus sensor sensing the light spot formed by the first light beam on the focus sensor;

[0009] Determining the central pixel position of the light spot based on the pixel data to determine the position of the light spot;

[0010] The pixel data includes a pixel data group of multiple pixels within the pixel range where the light spot is located, and each pixel data group includes a pixel position and a pixel gray value corresponding to the pixel position.

[0011] On the other hand, the present invention provides an autofocus method for an autofocus system. The autofocus system includes a lens module and a driving module. The lens module is used to irradiate a first light beam emitted by a first light source on the sample to be measured and collect the first light beam reflected from the sample to be measured. The driving module is connected to the lens module; the autofocus method includes:

[0012] Determine the spot position formed by the first beam on the focus sensor according to the above spot position detection method;

[0013] Determine the defocus amount of the sample to be measured based on the spot position of the first beam on the focus sensor;

[0014] Based on the defocus amount, make the driving module drive the lens module and / or the sample to be measured to move to eliminate the defocus amount.

[0015] Another aspect of the present invention provides an autofocus system, including:

[0016] A first light source, a beam transmission module, a lens module, a driving module and a focusing module;

[0017] The focusing module includes a focus sensor, a processor and a controller;

[0018] The processor is respectively connected to the focus sensor and the controller;

[0019] The controller is used to control the first light source to emit a first beam;

[0020] The beam transmission module is located on the transmission path of the first beam, and the beam transmission module is used to transmit the first beam to the lens module;

[0021] The lens module is used to project the first beam onto the sample to be measured and collect the first beam reflected from the sample to be measured;

[0022] The beam transmission module is used to receive the first beam reflected from the sample to be measured collected by the lens module and transmit the first beam to the focus sensor;

[0023] The processor is used to determine the defocus amount of the sample to be measured based on the spot position of the first beam on the focus sensor, and the spot position of the first beam on the focus sensor is determined according to the above spot position detection method;

[0024] The controller controls the driving module to drive the lens module to move to eliminate the defocus amount.

[0025] Another aspect of the present invention provides an optical imaging system, including the above autofocus system.

[0026] Another aspect of the present invention provides a sequencing system, including the above optical imaging system.

[0027] Another aspect of the present invention provides a computer-readable storage medium, on which a program is stored, and the program executes the above spot position detection method and / or the above autofocus method.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a method for detecting the position of a light spot for an autofocus system. The autofocus system includes a first light source and a focus sensor. By controlling the first light source to emit a first light beam to irradiate a sample to be measured and controlling the focus sensor to receive the first light beam reflected from the sample to be measured, pixel data generated by the focus sensor sensing the light spot formed on the focus sensor by the first light beam is obtained, and the central pixel position of the light spot is determined based on the pixel data to determine the position of the light spot. That is, through the present invention, the position of the light spot can be determined, so that the autofocus system can perform autofocus based on the position of the light spot, improving the image clarity. In addition, in the present invention, the central pixel position in the pixel data sensed by the focus sensor is used to determine the position of the light spot. Since the central pixel position can represent the central position of the light spot, determining the position of the light spot based on the central pixel position can make the determination of the position of the light spot more accurate, thereby improving the accuracy of autofocus and the image clarity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0031] Figure 1 Schematic diagram of a structure of an autofocus system provided by an embodiment of the present invention;

[0032] Figure 2 Schematic diagram of a structure of a focus module provided by an embodiment of the present invention;

[0033] Figure 3 Schematic diagram of another structure of an autofocus system provided by an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of yet another structure of an autofocus system provided by an embodiment of the present invention;

[0035] Figure 5 Method flowchart of a method for detecting the position of a light spot provided by an embodiment of the present invention;

[0036] Figure 6 Schematic diagram of pixel data provided by an embodiment of the present invention;

[0037] Figure 7 Data fitting diagram of the position of a light spot provided by an embodiment of the present invention;

[0038] Figure 8 Method flowchart of a method for autofocus provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] In order to improve the clarity of the images captured when an optical microscopy imaging system images different regions of a sample to be measured (such as a sequencing chip), an autofocus system can be used. The focusing process of the autofocus system includes emitting a focusing beam to the sample to be measured, and then determining whether the sample to be measured is located on the focal plane of the optical microscopy imaging system and the defocus amount based on the information of the spot formed by the focusing beam reflected from the surface of the sample to be measured. Then, based on the defocus amount, the optical microscopy imaging system and / or the sample to be measured are automatically adjusted to return the sample to be measured to the focal plane position of the optical microscopy imaging system to obtain a clear image of the sample to be measured. Among them, the information of the spot, such as the position information of the spot, the brightness information of the spot, etc. When determining the position of the spot, a PD (Photodiode) photodiode can be used to detect the position of the spot. However, the PD photodiode is greatly affected by temperature and stray light, resulting in the characteristic of weak anti-noise, and the accuracy of the spot position collected by the PD photodiode is low.

[0041] In order to improve the accuracy of determining the spot position, in the present invention, a method for detecting the spot position is provided for the autofocus system. In the present invention, the autofocus system includes a first light source and a focusing sensor. By controlling the first light source to emit a first beam to irradiate the sample to be measured and controlling the focusing sensor to receive the first beam reflected from the sample to be measured, the pixel data generated by the focusing sensor sensing the spot formed by the first beam on the focusing sensor is obtained, and the central pixel position of the spot is determined based on the pixel data to determine the spot position. That is, through the present invention, the spot position can be determined, enabling the autofocus system to perform autofocus based on the spot position and improving the image clarity. In addition, in the present invention, the central pixel position in the pixel data sensed by the focusing sensor is used to determine the spot position. Since the central pixel position can represent the central position of the spot, determining the spot position based on the central pixel position can make the accuracy of determining the spot position relatively high, thereby improving the accuracy of autofocus and the image clarity.

[0042] In practical applications, the focus sensor can be a CMOS (Complementary Metal Oxide Semiconductor) sensor, such as a one-dimensional linear array CMOS sensor. This sensor has the characteristic of high sensitivity and can capture high-quality CMOS linear array image data. In this embodiment, high resolution and noise resistance can be achieved by increasing the number of pixels of the CMOS and through a noise reduction algorithm, avoiding the influence of external environments such as temperature and stray light.

[0043] Based on the above content, an embodiment of the present invention provides an autofocus system. The structure of the autofocus system can be referred to Figure 1 and Figure 2 .

[0044] The autofocus system may include: a first light source 100, a light beam transmission module 300, a lens module 400, a drive module 600, and a focus module 500.

[0045] Among them, as Figure 2 shown, the focus module 500 includes a focus sensor 5001, a processor 5002, and a controller 5003. The processor 5002 is respectively connected to the focus sensor 5001 and the controller 5003. Among them, the focus sensor 5001 can be the above-mentioned CMOS sensor, and the processor 5002 can be an FPGA (Field Programmable Gate Array). The FPGA circuit has the advantages of programmability and parallelism, can quickly process a large amount of CMOS data, and can achieve efficient data transmission. The controller 5003 can be an MCU (Microcontroller Unit). The FPGA is respectively connected to the MCU and the CMOS sensor, and the MCU realizes the overall logic control, such as controlling the FPGA to collect CMOS data.

[0046] The first light source 100 is used to emit a first light beam. In practical applications, the first light source 100 can be a light source such as a laser diode that can output a first light beam. In practical applications, the controller 5003 can control the first light source 100 to emit a first light beam. Taking the first light source 100 as a laser diode as an example, the controller 5003 can control the output energy size of the laser diode, such as the output frequency, laser energy, etc. Control parameters such as output frequency and laser energy are pre-configured in the controller 5003, and then when the first light source 100 is required to output a first light beam, the controller 5003 sends the control parameters to the laser diode so that the first light source 100 outputs laser according to the control parameters.

[0047] In practical applications, the MCU controls the output magnitude of the laser energy and simultaneously controls the FPGA to collect CMOS data. The FPGA calculates the corresponding energy distribution based on the collected CMOS data and transmits the result to the MCU. The MCU adjusts the output of the laser energy according to the energy distribution returned by the FPGA.

[0048] In specific implementation, referring to Figure 3 , the autofocus system includes a beam shaping module 200. After the first light source 100 outputs a first beam, the beam shaping module 200 shapes the first beam. After being shaped, the first beam is transmitted through a beam transmission module 300. The beam transmission module 300 is located on the transmission path of the first beam. The beam transmission module 300 transmits the first beam to a lens module 400. The lens module 400 projects the first beam onto the sample to be measured 1 and collects the first beam reflected from the sample to be measured 1.

[0049] The beam transmission module 300 is located on the transmission path of the first beam and transmits the first beam to the lens module 400. The lens module 400 projects the first beam onto the sample to be measured 1 and collects the first beam reflected from the sample to be measured 1, that is, the lens module 400 projects the first beam onto the sample to be measured 1 and collects the part of the first beam reflected from the sample to be measured 1. The focusing module 500 includes a focusing sensor 5001, a processor 5002, and a controller 5003. The first beam reflected from the sample to be measured 1 forms a light spot on the focusing sensor 5001. The processor 5002 obtains the defocus amount of the sample to be measured 1 based on the light spot information of the first beam on the focusing sensor 5001, specifically referring to the defocus amount of the lens module 400 relative to the sample to be measured 1.

[0050] It should be understood that the sample to be measured 1 is placed on a stage. It should be noted that the defocus amount of the lens module 400 relative to the sample to be measured 1 is the distance between the focal plane of the lens module 400 and the sample to be measured 1. Optionally, the above lens module 400 includes a microscope, and the microscope includes an infinity conjugate objective lens. The above lens module 400 projects the first beam onto the sample to be measured 1 and collects the first beam reflected from the sample to be measured 1 is achieved through the above objective lens.

[0051] The controller 5003 controls the driving module 600 to drive the lens module 400 and / or the sample to be measured to move to eliminate the defocus amount. It should be noted that the driving module 600 driving the sample to be measured to move based on the defocus amount can be driving the stage carrying the sample to be measured to move based on the defocus amount.

[0052] As described above, during the operation of the autofocus system, the defocus amount of the lens module 400 relative to the sample to be measured 1 can be obtained by the focusing module 500 based on the first light beam reflected from the sample to be measured 1. After obtaining the defocus amount, the lens module 400 can be driven by the driving module 600 to move along its optical axis, or the sample to be measured can be driven by the driving module 600 to move along the optical axis of the lens module 400, or the driving module 600 can drive both the sample to be measured and the lens module 400 to move along the optical axis of the lens module 400 simultaneously to eliminate the defocus amount, that is, to eliminate the distance between the sample to be measured 1 and the focal plane of the lens module 400, so as to achieve autofocus on the sample to be measured 1, which can make different regions of the sample to be measured 1 image on the focal plane of the lens module 400, thereby ensuring the imaging quality of the sample to be measured 1, especially for the non-planar sample to be measured 1, the effect is more obvious.

[0053] Based on the above, in an embodiment of the present application, as Figure 4 shown, Figure 4 is a schematic structural diagram of an autofocus system provided by the present application. The beam shaping module 200 includes an aperture stop 201 and a light shielding sheet 202. The aperture of the aperture stop 201 matches the aperture of the first light source 100, and is used to adjust the spot diameter of the first light beam, that is, to adjust the beam aperture of the first light beam, and the purpose is to make the beam aperture of the subsequent first light beam meet the shooting requirements of the sample to be measured 1. The light shielding sheet 202 is used to adjust the spot shape of the first light beam. Specifically, after the first light beam passes through the light shielding sheet 202, its spot shape is a semi-circle.

[0054] The first light beam passes through the aperture stop 201 and the light shielding sheet 202 in sequence, and the shaped first light beam formed is a beam with a certain beam aperture and a semi-circular spot shape.

[0055] In some embodiments, when the sample to be measured 1 is located on the focal plane of the lens module 400, the spot formed by the first light beam reflected from the sample to be measured 1 on the focusing sensor 5001 is a dot; when the sample to be measured 1 is located above the focal plane of the lens module 400, the spot formed by the first light beam reflected from the sample to be measured 1 on the focusing sensor 5001 is a right semi-circle; when the sample to be measured 1 is located below the focal plane of the lens module 400, the spot formed by the first light beam reflected from the sample to be measured 1 on the focusing sensor is a left semi-circle. Therefore, the spot information of the first light beam reflected from the sample to be measured 1 detected by the focusing sensor 5001 can be used to determine whether the surface of the sample is located on the focal plane of the objective lens, providing a reference for the subsequent adjustment of the lens module 400 and / or the sample to be measured 1.

[0056] Based on the above, in an embodiment of the present application, continue as Figure 4As shown, the light beam transmission module 300 includes a beam splitter 301, a collimator 302, a first dichroic mirror 303, and a second dichroic mirror 304. The first light beam is transmitted through the beam splitter 301 to the collimator 302. After being collimated by the collimator 301, the first light beam is transmitted through the first dichroic mirror 303 and the second dichroic mirror 304 in sequence to the lens module 400.

[0057] The first light beam reflected from the sample 1 is collected by the lens module 400 , and then sequentially passes through the second dichroic mirror 304 and the first dichroic mirror 303 to the collimating mirror 302 . After being collimated by the collimating mirror 302 , the first light beam is reflected by the beam splitter 301 to the focus sensor 5001 .

[0058] The beam splitter 301, also known as an energy splitting plane, has the ability to transmit and reflect portions of the light beam, and its transmission-reflectance ratio can be 50:50, 70:30, 80:20, etc., depending on the specific circumstances. The first dichroic mirror 303 reflects the emitted light from the sample 1 to be tested, described below, and transmits the first light beam. The second dichroic mirror 304 reflects the second light beam to be tested, described below, and transmits the emitted light from the sample 1 to be tested and the first light beam reflected from the sample 1 to be tested, thereby separating the emitted light from the sample 1 to be tested, the first light beam reflected from the sample 1 to be tested, and the second light beam. This prevents light other than the first light beam reflected from the sample 1 from entering the focus sensor 5001, thereby affecting the accuracy of the defocus value and, in turn, the accuracy of the focus.

[0059] Based on the above, in one embodiment of the present application, continue as follows Figure 4 As shown, the beam transmission module 300 further includes a filter 305, which is located between the collimating lens 302 and the first dichroic mirror 303. The filter 305 transmits the first beam and highly reflects the second beam and the emitted light, thereby filtering the second beam and the emitted light of the sample 1 to be tested, thereby preventing the second beam and the emitted light of the sample 1 from entering the focus sensor 5001 and affecting the acquisition of the defocus value.

[0060] Based on the above, in one embodiment of the present application, continue as follows Figure 4 As shown, the autofocus also includes:

[0061] The first prism 801 and the second prism 802 are arranged such that the first prism 801 is located on the transmission path of the first light beam. The first light beam is redirected by the first prism 801 and then transmitted to the aperture 201. The second prism 802 is located on the transmission path of the first light beam reflected from the sample 1 to be tested. The first light beam reflected from the sample 1 to be tested is reflected by the beam splitter 301 and then transmitted to the second prism 802. The first light beam is redirected by the second prism 802 and then transmitted to the focus sensor 5001 in the focus module 500.

[0062] Specifically, in an embodiment of the present application, both the first prism 801 and the second prism 802 are right-angle prisms. The angle by which the transmission direction of the first light beam changes after passing through the first prism 801 is greater than 0° and less than or equal to 180°, and the angle by which the transmission direction of the first light beam reflected from the sample to be measured 1 changes after passing through the second prism 802 is greater than 0° and less than or equal to 180°. Thus, the optical path of the autofocus system is bent, and further, the size of the autofocus system can be reduced.

[0063] On this basis, in an embodiment of the present application, the first light source 100 is located at the object-side focus of the collimating mirror 301 so that the collimating mirror 301 can collimate the first light beam. The focus sensor 5001 in the focusing module 500 is located at the image-side focus of the collimating mirror 301 so that the collimating mirror 301 transmits the first light beam reflected from the sample to be measured 1 to the focus sensor 5001 in the focusing module 500.

[0064] On this basis, in an embodiment of the present application, continuing as Figure 4 shown, the autofocus system further includes:

[0065] A first reflecting mirror 901, which is located between the second prism 802 and the focus sensor 5001 in the focusing module 500. After the first light beam reflected from the sample to be measured 1 passes through the second prism 802, it is reflected by the first reflecting mirror 901 to the focus sensor 5001 in the focusing module 500, so that the optical path of the first light beam reflected from the sample to be measured 1 is bent, and further, the size of the autofocus system is reduced.

[0066] On this basis, in an embodiment of the present application, continuing as Figure 4 shown, the autofocus system further includes:

[0067] A second reflecting mirror 902, which is located between the beam shaping module 200 and the beam transmission module 300, and reflects the first light beam to the beam transmission module 300. Specifically, it is located between the light shielding sheet 202 and the beam splitting sheet 301, so that the optical path of the first light beam is bent, and further, the size of the autofocus system is reduced.

[0068] Optionally, in an embodiment of the present application, the focus sensor 5001 in the focusing module 500 is a linear array sensor. More specifically, it can be the above-mentioned one-dimensional linear array CMOS sensor.

[0069] Based on the above, denote the focal length of the lens module 400 as f1, the focal length of the collimating lens 302 as f2, the beam diameter of the first beam (before being reflected by the sample 1 to be measured), that is, the spot diameter, as D, the beam diameter of the first beam reflected from the sample 1 to be measured as r, and the defocus amount as δ. The above satisfies the following relational expression:

[0070] r = δDf2 / f1 2

[0071] According to the above relational expression, the defocus amount of the lens module 400 relative to the sample 1 to be measured can be obtained. And from the above relational expression, it can also be known that the beam diameter of the first beam reflected from the sample 1 to be measured changes linearly with the defocus amount. The processor 5002 can convert the defocus amount into a corresponding voltage difference, for example, the difference between the current voltage and the reference voltage. The reference voltage is converted based on the brightness value of the spot on the focus sensor 5001 when the sample 1 to be measured is on the focal plane. Then the driving module 600 drives the lens module 400 to move based on this voltage difference, thereby eliminating the defocus amount between the lens module 400 and the sample 1 to be measured and ensuring the imaging quality of the sample 1 to be measured. It should be noted that if the lens module 400 is a microscope, the focal length of the above lens module 400 is the focal length of the objective lens of the microscope.

[0072] In another implementation manner of the present invention, the determination process of the above defocus amount is given. Specifically, it may include: the processor 5002 determines the defocus amount of the sample 1 to be measured based on the offset amount of the spot position of the first beam on the focus sensor 5001 deviating from the reference spot position and a preset relationship, or determines the defocus amount of the sample 1 to be measured based on the offset amount of the electrical signal converted from the pixel gray value corresponding to the spot position of the first beam on the focus sensor deviating from the reference electrical signal and a preset relationship.

[0073] Among them, the reference spot position is the spot position of the first beam on the focus sensor 5001 determined when the sample 1 to be measured is on the focal plane of the lens module 400 and / or when a clear image of the sample 1 to be measured is obtained.

[0074] Specifically speaking, after the first beam forms a spot on the focus sensor 5001, this spot has a specific position on the focus sensor. The present invention uses the spot position when the sample 1 to be measured is on the focal plane of the lens module 400 and / or when a clear image of the sample 1 to be measured is obtained as the reference spot position, and this reference spot position is used as a reference value for calculating the defocus amount during subsequent focusing.

[0075] When determining the clear image, the driving module 600 controls the lens module 400 to move along its optical axis by a preset step distance (for example, 0.3 um). For each movement, the optical microscopy imaging system takes a picture of a specified area of the sample to be measured to obtain an image. Through multiple movements, multiple images of the specified area can be obtained, and the image with the highest clarity is selected as the above-mentioned clear image.

[0076] In addition, the preset relationship in the present invention is specifically:

[0077] ΔZ = K * Δb or ΔZ = K * ΔP.

[0078] Where,

[0079] ΔZ is the defocus amount;

[0080] Δb is the offset amount of the spot position;

[0081] ΔP is the offset amount of the electrical signal;

[0082] K is a preset coefficient.

[0083] The preset relationship ΔZ = K * Δb can be obtained in the following manner:

[0084] Obtain the preset step distance (for example, 0.3 um), drive the lens module 400 to move along its optical axis by the preset step distance, and after each movement, determine the offset amount of the spot position of the first light beam deviating from the reference spot position on the focus sensor 5001 and the defocus amount of the sample 1 to be measured. Among them, the offset amount refers to the offset amount of the spot position, which can be obtained by calculating the distance between the spot position of the first light beam on the focus sensor 5001 and the reference spot position after each movement. The defocus amount refers to the distance by which the sample to be measured deviates from the focal plane of the lens module 400, which can be obtained by calculating the distance between the current position of the lens module 400 and its reference position after each movement. The reference position of the lens module 400 can be, for example, the position of the lens module 400 in the optical axis direction when the sample to be measured is located on its focal plane.

[0085] Perform fitting based on multiple offset amounts and multiple defocus amounts to obtain the fitting relationship between the offset amount and the defocus amount. This fitting relationship can be a linear relationship, and the fitting relationship is used as the preset relationship.

[0086] In addition, when determining the defocus amount, the offset amount can also be obtained by converting the pixel gray value corresponding to the spot position into an electrical signal. At this time, after determining the spot position, it is necessary to further determine the signal conversion of the pixel gray value corresponding to the spot position to obtain the converted electrical signal, and the electrical signal can specifically be a voltage signal.

[0087] In the specific process of determining the defocus amount, the defocus amount of the sample 1 to be tested is determined based on the offset (electrical signal difference) of the electrical signal obtained by converting the pixel grayscale value corresponding to the light spot position of the first light beam on the focus sensor 5001 (which can be obtained through the focus sensor 5001) from the reference electrical signal and the preset relationship, wherein the reference electrical signal is converted from the pixel grayscale value corresponding to the reference light spot position of the first light beam on the focus sensor 5001.

[0088] The reference light spot position is the light spot position of the first light beam on the focus sensor 5001 determined when the sample 1 to be tested is located on the focal plane of the lens module 400 and / or a clear image of the sample 1 to be tested is obtained;

[0089] At this time, the preset relationship is ΔZ=K*ΔP, where ΔP represents the offset of the electrical signal and can be output as an analog voltage.

[0090] ΔZ=K*ΔP is obtained in the following way:

[0091] The lens module 400 is driven to move along its optical axis at a preset step distance, and after each movement, the offset of the electrical signal corresponding to the spot position of the first light beam on the focus sensor 5001 from the reference electrical signal and the defocus amount of the sample to be measured 1 are determined; fitting is performed based on multiple offsets and multiple defocus amounts to obtain a fitting relationship between the offset and the defocus amount, and the fitting relationship is used as the preset relationship.

[0092] After obtaining the defocus amount, the driving module 600 drives the lens module 400 and / or the sample to be tested 1 to move along the optical axis of the lens module 400 to eliminate the defocus amount. The focusing process can be as follows: start focusing, determine the reference electrical signal (Vtarget), and when it is detected that the electrical signal corresponding to the spot position of the first light beam on the focus sensor 5001 deviates from Vtarget, control the lens module 400 to move until the electrical signal corresponding to the spot position of the first light beam on the focus sensor 5001 detected in real time is close to or the same as Vtarget.

[0093] In this embodiment, after the defocus amount is determined by various methods, the driving module 600 can be used to drive the lens module 400 and / or the sample to be tested 1 to move along the optical axis of the lens module 400 to eliminate the defocus amount, achieve automatic focus, and ensure the clarity of the image when the optical microscopy imaging system images different areas of the sample to be tested.

[0094] Based on the above-mentioned autofocus system, another embodiment of the present invention provides an optical imaging system, which includes the above-mentioned autofocus system.

[0095] Based on the above, in one embodiment of the present application, continue as follows Figure 4 As shown, the optical imaging system also includes:

[0096] A second light source 700 is configured to output a second light beam. The second dichroic mirror 304 is also located on the transmission path of the second light beam, and the second dichroic mirror 304 is further configured to reflect the second light beam to the lens module 400, so that the second light beam is transmitted to the sample to be measured 1 to excite the sample to be measured 1 to generate emitted light, such as fluorescence. After the above-mentioned emitted light is collected by the lens module 400, it passes through the second dichroic mirror 304 and the first dichroic mirror 303 in sequence, and is reflected by the first dichroic mirror 303, specifically, it can be reflected to the imaging module 800. The imaging module 800 includes an image sensor for detecting and imaging the sample to be measured 1.

[0097] Based on the above optical imaging system, the present application further provides a sequencing system, which includes the optical imaging system described in any one of the above embodiments.

[0098] In summary, the present application provides an autofocus system, an optical imaging system and a sequencing system. The first light source outputs a first light beam, and the beam shaping module shapes the first light beam. After the first light beam is shaped, the beam transmission module transmits the first light beam to the lens module. The lens module transmits the first light beam to the sample to be measured 1 and collects the first light beam reflected from the sample to be measured 1. The beam transmission module receives the first light beam reflected from the sample to be measured 1 collected by the lens module and transmits the first light beam to the focusing module. The focusing module obtains the defocus amount of the lens module relative to the sample to be measured 1 based on the first light beam reflected from the sample to be measured 1, and the driving module drives the lens module to move based on the defocus amount to eliminate the defocus amount. It can be seen that the present invention can obtain the defocus amount of the lens module relative to the sample to be measured 1 based on the first light beam reflected from the sample to be measured 1 by the focusing module. After obtaining the above defocus amount, the driving module can drive the lens module to move along its optical axis to eliminate the above defocus amount, that is, to eliminate the distance between the focal plane of the sample to be measured 1 and the lens module, and achieve autofocus on different regions of the sample to be measured 1, so that different regions of the sample to be measured 1 can be imaged on the focal plane of the lens module, thereby ensuring the imaging quality of the sample to be measured 1, especially for the non-planar sample to be measured 1, the effect is more obvious.

[0099] The above embodiments mention the spot position. In another embodiment of the present invention, a spot position detection method is provided for an autofocus system to implement the detection of the above spot position. The autofocus system includes a first light source and a focusing sensor, and the focusing sensor is a linear array sensor, such as a one-dimensional linear array CMOS sensor. The structural description of the autofocus system can refer to the corresponding description above. <{

[0100] Refer to Figure 5 , a spot position detection method may include:

[0101] S11 , controlling the first light source to emit a first light beam to illuminate the sample to be tested.

[0102] Specifically, the entire light spot position detection method is implemented by a controller. The controller controls the first light source to output the first light beam. The light beam transmission module is located on the transmission path of the first light beam and transmits the first light beam to the lens module. The lens module projects the first light beam onto the sample to be tested.

[0103] S12: Control the focus sensor to receive the first light beam reflected from the sample to be measured.

[0104] Specifically, the light beam transmission module receives the first light beam reflected from the sample to be tested 1 and transmits it to the focus sensor to form a light spot on the focus sensor.

[0105] S13 , obtaining pixel data generated by the focus sensor sensing a light spot formed on the focus sensor by the first light beam.

[0106] In actual applications, after the first light beam forms a light spot on the focus sensor, the focus sensor can sense the light spot and generate pixel data. The pixel data can be, for example, CMOS data. The pixel data includes a pixel data group of multiple pixels within the pixel range where the light spot is located. Each pixel data group includes a pixel position and a pixel grayscale value corresponding to the pixel position.

[0107] In some embodiments, the focus sensor is a linear array sensor, which includes a plurality of linearly arranged pixels. The plurality of pixels are numbered in sequence along the linear arrangement direction so that each pixel has a corresponding serial number. The serial number can be, for example, Figure 6 The horizontal axis shows 1, 2, 3, ..., 251. The pixel position of each pixel can be determined according to the serial number corresponding to the pixel. When the linear array sensor senses a light spot, the pixel position of each pixel in the pixel range where the light spot is located has a corresponding pixel grayscale value (sometimes also directly called grayscale value or brightness value). The pixel grayscale value is as follows: Figure 6 As shown in the vertical axis, the pixel position of each pixel and its corresponding pixel gray value constitute a pixel data group. Each pixel data group can be represented by Figure 6 One data point (solid circle) is shown in FIG.

[0108] In practical applications, Figure 6 The data points with larger pixel grayscale values in the embodiment of the present invention constitute the light spot, but Figure 6 It can be seen that in addition to the light spot formed by the first light beam, there are also some stray data, such as data points with smaller pixel grayscale values. These data points are pixel data generated by the focus sensor sensing light beams other than the first light beam.

[0109] Therefore, in order to prevent stray data from affecting the accuracy of subsequent light spot position determination, pixel data generated by the focus sensor sensing non-first light beams may be removed before determining the center pixel position of the light spot based on the pixel data.

[0110] The specific removal method can use a filtering algorithm, and the specific process of the filtering algorithm is:

[0111] by Figure 6 As shown in the figure, with the maximum value of the pixel gray value as the center, a certain number of data points are selected on both sides to participate in the calculation. The points not involved in the calculation are filtered out as noise. For the data points involved in the data calculation, an adaptive filtering algorithm is adopted. The adaptive filtering algorithm is as follows:

[0112] 1) For a point below the highest peak value of the pixel grayscale value, if a second peak or valley appears, the current point is interpolated from the two adjacent points;

[0113] 2) If the values of the points near the selected boundary fluctuate greatly, filter out these points with large fluctuations.

[0114] By using the filtering algorithm in this embodiment, stray light other than the first light beam can be filtered out, thereby avoiding the adverse effect of stray light on the determination of the light spot position.

[0115] S14. Determine the center pixel position of the light spot based on the pixel data to determine the light spot position.

[0116] In practical applications, after the pixel data is known, the center pixel position can be determined therefrom. The center pixel position represents the center position of the light spot, and the light spot position can be determined based on the center pixel position.

[0117] Specifically, the Gaussian fitting formula can quickly achieve data fitting. This algorithm is highly adjustable and adaptable, and can adapt to optical imaging and measurement tasks in different scenarios and requirements. Therefore, in this embodiment, the Gaussian fitting formula is used to determine the center pixel position of the light spot.

[0118] The Gaussian fitting formula is as follows:

[0119] y=a*exp(-(xb)^2 / (2*c^2)) Formula (I)

[0120] Among them, x represents the pixel position and y represents the pixel grayscale value;

[0121] a, b, and c are unknown fitting parameters, a represents the maximum pixel grayscale value, b represents the center pixel position, and c represents the standard deviation.

[0122] Therefore, in this embodiment, the center pixel position of the light spot is determined based on the pixel data using formula (I).

[0123] When determining the central pixel position of the light spot using the above formula (I), it needs to be achieved through multiple iterations. During the iteration, it is necessary to obtain the preset initial values of a, b, and c above, and the preset initial values can be determined by technicians according to experience.

[0124] Then, input the above a, b, and c into formula (I) for iterative operations. In the specific iteration process, based on the preset initial values and pixel data, use formula (I) to iterate a, b, and c to update their estimated values. That is, in each iteration, there will be new values corresponding to a, b, and c, which are used as the estimated values.

[0125] The iteration process is complex and takes a lot of time. In this embodiment, in order to improve the iteration efficiency and reduce the time consumption, based on the preset initial values and pixel data, use formula (I) to iterate a, b, and c using the gradient descent method to update their estimated values.

[0126] When using the gradient descent method for iterative update, it is necessary to pre-configure the iteration convergence condition. In this embodiment, when using the gradient descent method to iterate a, b, and c to update their estimated values, determine the iteration convergence when the square loss function L shown in formula (II) reaches the minimum value or reaches the preset number of iterations.

[0127] L = Σ(y i -(a * exp(-(x i -b)^2 / (2*c^2)))^2) Formula (II)

[0128] When the square loss function L in this embodiment reaches the minimum value, it means that the currently determined estimated values of a, b, and c are relatively good, and the iteration can be stopped. In this embodiment, to determine that the square loss function L reaches the minimum value, it can be that during multiple iterations, it is found that the value of the square loss function L shows a trend of decreasing overall and gradually stabilizes near a certain value, fluctuating continuously. At this time, it is considered that the iteration is approaching the end, and the minimum square loss function L can be selected near this value.

[0129] In addition, if after multiple iterations, it still cannot stabilize near a certain value, but the number of iterations is already large, the iteration convergence can be determined when the preset number of iterations is reached, and the iteration is stopped. The preset number of iterations in this embodiment is set according to experience.

[0130] In the specific implementation of the present invention, when using the gradient descent method to iterate a, b, and c using formula (I) based on the preset initial values and pixel data to update their estimated values, it can be as follows:

[0131] Use formulas (III), (IV), and (V) to iterate a, b, and c using the gradient descent method to update their estimated values respectively.

[0132] a update = a - α * Σ((y i - (a * exp(-(x i - b)^2 / (2 * c^2))) * exp(-(x i - b)^2 / (2 * c^2)) * (-(x i - b)^2 /

[0133] (c^2 * exp(-(x i - b)^2 / (2 * c^2))));

[0134] Equation (III)

[0135] b update = b - α * Σ((y i - (a * exp(-(x i - b)^2 / (2 * c^2))) * exp(-(x i - b)^2 / (2 * c^2)) * (-2 * (x i - b)

[0136] / (c^2 * exp(-(x i - b)^2 / (2 * c^2))));

[0137] Equation (IV)

[0138] c update = c - α * Σ((y i - (a * exp(-(x i - b)^2 / (2 * c^2))) * exp(-(x i - b)^2 /

[0139] (2 * c^2)) * ((x i - b)^2 / (c^4 * exp(-(x i - b)^2 / (2 * c^2)))),

[0140] Equation (V)

[0141] Where, α is the step coefficient, used to control the optimization speed, x i represents the pixel position of the i-th pixel, y i represents the pixel gray value of the i-th pixel, a update represents the estimated value of a, b update represents the estimated value of b, c update represents the estimated value of c.

[0142] Specifically, in the first iteration process, the preset initial values of a, b, and c above, x i、 yi Substituting the above formulas (III), (IV), and (V) gives a update , b update , and c update . Then calculate the squared loss function L for this iteration.

[0143] Continue to the next iteration and repeat the above iteration process until the squared loss function L reaches the minimum value or reaches the preset number of iterations, at which point the iteration converges, and obtain the estimated values of a, b, and c at the time of iteration convergence.

[0144] At this time, take the estimated value of b as the central pixel position of the light spot, and take this central pixel position as the light spot position of the first beam on the focus sensor. Refer to Figure 7 . When the sample to be measured is out of focus, the light spot on the CMOS will change. In the linear range, data is collected every 0.3 um interval, 8 data points are collected, and the relationship between the offset of the fitted light spot position and the defocus amount is a straight line, which conforms to the above ΔZ = K * Δb. With the present invention, a position change less than 0.3 um can be identified.

[0145] In another implementation of the present invention, after determining the light spot position, the pixel gray value corresponding to the light spot position can be converted into an electrical signal to perform the above calculation of the defocus amount. For the calculation process of the defocus amount, please refer to the corresponding description above. In this embodiment, the autofocus system includes a first light source and a focus sensor. By controlling the first light source to emit a first beam to irradiate the sample to be measured and controlling the focus sensor to receive the first beam reflected from the sample to be measured, pixel data generated by the focus sensor sensing the first beam formed on the focus sensor is obtained, and the central pixel position of the light spot is determined based on the pixel data to determine the light spot position. That is, with the present invention, the light spot position can be determined, enabling the autofocus system to perform autofocus based on the light spot position and improving the image clarity. In addition, in the present invention, the central pixel position in the pixel data sensed by the focus sensor is used to determine the light spot position. Since the central pixel position can represent the center position of the light spot, determining the light spot position based on the central pixel position can make the determination of the light spot position more accurate, thereby improving the accuracy of autofocus and the image clarity.

[0146] Based on the above method for detecting the light spot position, another embodiment of the present invention provides an autofocus method for an autofocus system, where the autofocus system includes a lens module and a driving module. The lens module is used to irradiate a first beam emitted by a first light source on the sample to be measured and collect the first beam reflected from the sample to be measured, and the driving module is connected to the lens module.

[0147] Referring to 8, the autofocus method may include:

[0148] S21 . Determine a spot position formed by the first light beam on the focus sensor.

[0149] In practical applications, the above-mentioned light spot position detection method can be used to detect the light spot position in this embodiment.

[0150] S22. Determine the defocus amount of the sample to be measured based on the spot position of the first light beam on the focus sensor.

[0151] Specifically, there are two ways to implement step S22:

[0152] The first implementation method:

[0153] Determining a defocus amount of the sample to be measured based on an offset amount of a spot position of the first light beam on the focus sensor from a reference spot position and a preset relationship;

[0154] The reference light spot position is the light spot position of the first light beam on the focus sensor determined according to the light spot position detection method when the sample to be tested is located on the focal plane of the lens module and / or a clear image of the sample to be tested is obtained;

[0155] The preset relationship is obtained in the following way:

[0156] driving the lens module to move along its optical axis at a preset step length, and determining, after each movement, an offset of a spot position of the first light beam on the focus sensor from a reference spot position and a defocus amount of the sample to be measured;

[0157] Fitting is performed based on the multiple offsets and the multiple defocus amounts to obtain a fitting relationship between the offsets and the defocus amounts, and the fitting relationship is used as a preset relationship.

[0158] The second implementation method:

[0159] Determining the defocus amount of the sample to be measured based on an offset of an electrical signal obtained by converting a pixel grayscale value corresponding to a spot position of the first light beam on the focus sensor from a reference electrical signal and a preset relationship;

[0160] The reference electrical signal is obtained by converting the pixel grayscale value corresponding to the reference light spot position of the first light beam on the focus sensor;

[0161] The reference light spot position is the light spot position of the first light beam on the focus sensor determined according to the light spot position detection method when the sample to be tested is located on the focal plane of the lens module and / or a clear image of the sample to be tested is obtained;

[0162] The preset relationship is obtained in the following way:

[0163] Drive the lens module to move along its optical axis by a preset step distance, and after each movement, determine the offset of the electrical signal of the spot position of the first light beam on the focus sensor from the reference electrical signal and the defocus amount of the sample to be measured;

[0164] Perform fitting based on multiple offsets and multiple defocus amounts to obtain the fitting relationship between the offset and the defocus amount, and use the fitting relationship as the preset relationship.

[0165] It should be noted that for the specific implementation in this embodiment, please refer to the corresponding description above.

[0166] S23. Based on the defocus amount, make the drive module drive the lens module and / or the sample to be measured to move to eliminate the defocus amount.

[0167] Specifically, make the drive module drive the lens module and / or the sample to be measured to move along the optical axis of the lens module to eliminate the defocus amount.

[0168] It should be noted that for the specific implementation in this embodiment, please refer to the corresponding description above.

[0169] In this embodiment, after determining the defocus amount through various methods, the drive module can be used to drive the lens module and / or the sample to be measured to move along the optical axis of the lens module to eliminate the defocus amount, ensuring the image clarity when the optical microscopy imaging system images different regions of the sample to be measured.

[0170] On the basis of the above content, another embodiment of the present invention provides a computer-readable storage medium, on which a program is stored, and the program executes the above-mentioned spot position detection method and / or the above-mentioned autofocus method.

[0171] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A light spot position detection method for an autofocus system, characterized in that: The autofocus system includes a first light source and a focus sensor; The method comprises: Controlling the first light source to emit a first light beam to illuminate the sample to be tested; controlling the focus sensor to receive a first light beam reflected from the sample to be measured; Acquiring pixel data generated by the focus sensor sensing a light spot formed on the focus sensor by the first light beam; determining a central pixel position of the light spot based on the pixel data to determine the light spot position; The pixel data includes pixel data groups of multiple pixels within the pixel range where the light spot is located, and each pixel data group includes a pixel position and a pixel grayscale value corresponding to the pixel position.

2. The light spot position detection method according to claim 1, characterized in that: Before determining the central pixel position of the light spot based on the pixel data, the method further includes: removing pixel data generated by the focus sensor sensing light beams other than the first light beam; Optionally, The determining the central pixel position of the light spot based on the pixel data includes: Based on the pixel data, determining the center pixel position of the light spot using formula (I); y=a*exp(-(xb)^2 / (2*c^2)) Formula (I) Among them, x represents the pixel position and y represents the pixel grayscale value; a, b, and c are unknown fitting parameters, where a represents the maximum pixel grayscale value, b represents the center pixel position, and c represents the standard deviation; Optionally, determining the central pixel position of the light spot based on pixel data includes: Get the preset initial values of a, b, and c; Based on the preset initial value and the pixel data, iterating the a, b, and c using formula (I) to update their estimated values; After determining that the iteration has converged, taking the estimated value of b as the central pixel position of the light spot; Optionally, based on the preset initial value and the pixel data, iterating the a, b, and c using formula (I) to update their estimated values includes: Based on the preset initial value and the pixel data, using formula (I), the gradient descent method is used to iterate the a, b, and c to update their estimated values; Optionally, a, b, and c are iterated using a gradient descent method to update their estimated values, including: The iteration convergence is determined when the square loss function L shown in formula (II) reaches a minimum value or when a preset number of iterations is reached; L=Σ(y i -(a*exp(-(x i -b)^2 / (2*c^2)))^2) Formula (II); Optionally, based on the preset initial value and the pixel data, using formula (I) to iterate a, b, and c using a gradient descent method to update their estimated values, including: Using formulas (III), (IV) and (V) respectively, the gradient descent method is used to iterate the a, b, and c to update their estimated values. a update =a-α*Σ((y i -(a*exp(-(x i -b)^2 / (2*c^2)))*exp(-(x i -b)^2 / (2*c^2))*(-(x i -b)^2 / (c^2*exp(-(x i -b)^2 / (2*c^2))))); Formula (III) b update =b-α*Σ((y i -(a*exp(-(x i -b)^2 / (2*c^2)))*exp(-(x i -b)^2 / (2*c^2))*(-2*(x i -b) / (c^2*exp(-(x i -b)^2 / (2*c^2))))); Formula (IV) c update =c-α*Σ((y i -(a*exp(-(x i -b)^2 / (2*c^2)))*exp(-(x i -b)^2 / (2*c^2))*((x i -b)^2 / (c^4*exp(-(x i -b)^2 / (2*c^2))))), Formula (V) Among them, α is the step coefficient, x i represents the pixel position of the i-th pixel, y i Represents the pixel gray value of the i-th pixel, a update represents the estimated value of a, b update represents the estimated value of b, c update represents the estimated value of c; Optionally, after determining the light spot position, the method includes: Converting the pixel grayscale value corresponding to the light spot position into an electrical signal; Optionally, the focus sensor is a line array sensor.

3. An autofocus method for an autofocus system, characterized in that: The autofocus system includes a lens module and a driving module, wherein the lens module is used to emit a first light beam from the first light source to illuminate the sample to be tested and collect the first light beam reflected from the sample to be tested, and the driving module is connected to the lens module; The method comprises: The light spot position detection method according to claim 1 or 2 determines the light spot position formed by the first light beam on the focus sensor; determining a defocus amount of the sample to be measured based on a spot position of the first light beam on the focus sensor; Based on the defocus amount, the driving module drives the lens module and / or the sample to be measured to move to eliminate the defocus amount.

4. The automatic focusing method according to claim 3, wherein: The determining the defocus amount of the sample to be measured based on the spot position of the first light beam on the focus sensor includes: Determining a defocus amount of the sample to be measured based on an offset amount of a spot position of the first light beam on the focus sensor from a reference spot position and a preset relationship; The reference light spot position is the light spot position of the first light beam on the focus sensor determined by the light spot position detection method according to claim 1 or 2 when the sample to be tested is located on the focal plane of the lens module and / or a clear image of the sample to be tested is obtained; The preset relationship is obtained in the following manner: driving the lens module to move along its optical axis at a preset step length, and determining, after each movement, an offset of a spot position of the first light beam on the focus sensor from a reference spot position and a defocus amount of the sample to be measured; Performing fitting based on the plurality of offsets and the plurality of defocus amounts to obtain a fitting relationship between the offsets and the defocus amounts, and using the fitting relationship as the preset relationship; Optionally, determining the defocus amount of the sample to be measured based on the spot position of the first light beam on the focus sensor includes: Determining a defocus amount of the sample to be measured based on an offset of an electrical signal obtained by converting a pixel grayscale value corresponding to a spot position of the first light beam on the focus sensor from a reference electrical signal and a preset relationship; The reference electrical signal is obtained by converting the pixel grayscale value corresponding to the reference light spot position of the first light beam on the focus sensor; The reference light spot position is the light spot position of the first light beam on the focus sensor determined by the light spot position detection method according to claim 1 or 2 when the sample to be tested is located on the focal plane of the lens module and / or a clear image of the sample to be tested is obtained; The preset relationship is obtained in the following manner: driving the lens module to move along its optical axis at a preset step length, and determining, after each movement, an offset of an electrical signal of a light spot position of the first light beam on the focus sensor from a reference electrical signal and a defocus amount of the sample to be measured; Performing fitting based on the plurality of offsets and the plurality of defocus amounts to obtain a fitting relationship between the offsets and the defocus amounts, and using the fitting relationship as the preset relationship; Optionally, based on the defocus amount, the driving module drives the lens module and / or the sample to be tested to move to eliminate the defocus amount, including causing the driving module to drive the lens module and / or the sample to be tested to move along the optical axis of the lens module to eliminate the defocus amount.

5. An autofocus system, characterized in that: include: A first light source, a beam transmission module, a lens module, a driving module and a focusing module; The focus module includes a focus sensor, a processor and a controller; The processor is connected to the focus sensor and the controller respectively; The controller is used to control the first light source to emit a first light beam; The light beam transmission module is located on the transmission path of the first light beam, and is used to transmit the first light beam to the lens module; The lens module is used to project the first light beam onto the sample to be tested and collect the first light beam reflected from the sample to be tested; The light beam transmission module is used to receive the first light beam reflected from the sample to be measured and collected by the lens module and transmit the first light beam to the focus sensor; The processor is configured to determine a defocus amount of the sample to be measured based on a spot position of the first light beam on the focus sensor, wherein the spot position of the first light beam on the focus sensor is determined according to the spot position detection method according to claim 1 or 2; The controller controls the driving module to drive the lens module to move so as to eliminate the defocus amount.

6. The autofocus system according to claim 5, wherein: The processor determines the defocus amount of the sample to be measured based on the spot position of the first light beam on the focus sensor, including: The processor determines a defocus amount of the sample to be measured based on an offset amount of a spot position of the first light beam on the focus sensor from a reference spot position and a preset relationship; The reference light spot position is the light spot position of the first light beam on the focus sensor determined by the light spot position detection method according to claim 1 or 2 when the sample to be tested is located on the focal plane of the lens module and / or a clear image of the sample to be tested is obtained; The preset relationship is obtained in the following manner: driving the lens module to move along its optical axis at a preset step length, and determining, after each movement, an offset of a spot position of the first light beam on the focus sensor from a reference spot position and a defocus amount of the sample to be measured; Performing fitting based on the plurality of offsets and the plurality of defocus amounts to obtain a fitting relationship between the offsets and the defocus amounts, and using the fitting relationship as the preset relationship; Optionally, determining the defocus amount of the sample to be measured based on the spot position of the first light beam on the focus sensor includes: Determining a defocus amount of the sample to be measured based on an offset of an electrical signal obtained by converting a pixel grayscale value corresponding to a spot position of the first light beam on the focus sensor from a reference electrical signal and a preset relationship; The reference electrical signal is obtained by converting the pixel grayscale value corresponding to the reference light spot position of the first light beam on the focus sensor; The reference light spot position is the light spot position of the first light beam on the focus sensor determined by the light spot position detection method according to claim 1 or 2 when the sample to be tested is located on the focal plane of the lens module and / or a clear image of the sample to be tested is obtained; The preset relationship is obtained in the following manner: driving the lens module to move along its optical axis at a preset step length, and determining, after each movement, an offset of an electrical signal of a light spot position of the first light beam on the focus sensor from a reference electrical signal and a defocus amount of the sample to be measured; Performing fitting based on the plurality of offsets and the plurality of defocus amounts to obtain a fitting relationship between the offsets and the defocus amounts, and using the fitting relationship as the preset relationship; Optionally, based on the defocus amount, the controller controls the driving module to drive the lens module to move to eliminate the defocus amount, comprising: causing the driving module to drive the lens module and / or the sample to be measured to move along the optical axis of the lens module to eliminate the defocus amount; Optionally, the autofocus system further includes a beam shaping module, which is located on a transmission path of the first light beam and shapes the first light beam; Optionally, the beam shaping module includes a stop and a light shield; The aperture adjusts the spot diameter of the first light beam; The light shielding sheet adjusts the spot shape of the first light beam; Optionally, the beam transmission module includes a beam splitter, a collimator, a first dichroic mirror, and a second dichroic mirror; The first light beam is transmitted through the beam splitter to the collimator, and after being collimated by the collimator, is sequentially transmitted through the first dichroic mirror and the second dichroic mirror to the lens module; The first light beam reflected from the sample to be measured is collected by the lens module, sequentially transmitted through the second dichroic mirror and the first dichroic mirror to the collimator, collimated by the collimator, and reflected by the beam splitter to the focus sensor; Optionally, the beam transmission module further comprises a filter, wherein the filter is located between the collimating mirror and the first dichroic mirror; The first filter transmits the first light beam; Optionally, the autofocus system further comprises: a first prism and a second prism; The first prism is located on the transmission path of the first light beam, and the first light beam is transmitted to the aperture after changing its transmission direction through the first prism; The second prism is located on the transmission path of the first light beam reflected from the sample to be measured. The first light beam reflected from the sample to be measured is reflected by the beam splitter and then transmitted to the second prism. The second prism changes the transmission direction and then transmits it to the focus sensor. Optionally, the first prism and the second prism are both right-angle prisms; The angle at which the first light beam changes its transmission direction after passing through the first prism is greater than 0° and less than or equal to 180°, and the angle at which the first light beam reflected from the sample changes its transmission direction after passing through the second prism is greater than 0° and less than or equal to 180°; Optionally, the first light source is located at the object-side focus of the collimator; The focus sensor is located at the image side focus of the collimating mirror; Optionally, the autofocus system further comprises: a first reflecting mirror, the first reflecting mirror being located between the second prism and the focus sensor, The first light beam reflected from the sample to be measured passes through the second prism and is then reflected by the first reflector to the focus sensor; Optionally, the autofocus system further comprises: a second reflector, located between the beam shaping module and the beam transmission module, and reflecting the first light beam to the beam transmission module; Optionally, the focus sensor is a line array sensor.

7. An optical imaging system, characterized in that: The optical imaging system includes the autofocus system according to claim 5 or 6.

8. The optical imaging system according to claim 7, wherein: include: A second light source outputs a second light beam, which is transmitted to the sample to be tested through the lens module to excite the sample to be tested to generate emitted light, and the emitted light is collected by the lens module and transmitted to the image sensor for imaging.

9. A sequencing system, characterized in that Comprising the optical imaging system according to claim 7 or 8.

10. A computer-readable storage medium, characterized in that The medium stores a program, wherein the program executes the light spot position detection method according to claim 1 or 2 and / or the autofocus method according to claim 3 or 4.

Images