Microlens array zoom module zoom method and imaging system

Abstract

The present invention is applicable to the field of imaging and discloses a microlens array zoom module zoom method and an imaging system. The method comprises: obtaining a mapping relationship table between a deviation from an objective lens working distance and a microlens array state of the microlens array zoom module; obtaining a laser spot image formed by laser irradiation of an object to be measured, and calculating a position from the object to be measured to a focal plane of the objective lens; determining an adjustment reference distance of the microlens array zoom module based on the position from the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with the mapping relationship table to determine the microlens array state of the microlens array zoom module; and generating a focus instruction based on the determined microlens array state to realize automatic zooming of the microlens array zoom module. Automatic zooming of the microlens array zoom module has the advantages of extremely fast focusing speed and high precision.

Description

Technical Field

[0001] The present invention relates to the field of imaging technology, and in particular to a microlens array zoom module zoom method and an imaging system. Background Art

[0002] In the optical automation inspection process of high-end equipment manufacturing such as semiconductors, integrated circuits, and display panels, high-magnification optical objectives are often used for inspection and imaging to achieve high spatial resolution. Although high-NA and high-magnification objectives can achieve high lateral resolution, the depth of field of the lens is relatively narrow. For objects with highly complex surface topography or warped surfaces, the depth of field can easily exceed the measurement range, resulting in blurred images. Therefore, high-magnification microscopic imaging technology that can adapt to focal plane changes and has focal plane tracking is in great demand in the field of high-precision inspection.

[0003] Traditional microlens array zoom module automatic focusing technologies include two types. The first is active focus technology, which uses a laser to measure the focal plane of an object and feeds the measurement value back to a motion platform. The motion platform then moves the imaging device along the optical axis based on the position of the focal plane to achieve focused image acquisition. Due to the heavy load on the motion platform and the camera itself, this technology has a slow focusing speed. The mechanical movement is prone to jitter errors, which can introduce additional imaging errors in high-resolution imaging. The motion mechanism's long-term reciprocating motion and the presence of mechanical modes can lead to reduced accuracy. The second is passive focus technology, which acquires images at multiple positions along the optical axis near the focal plane and selects the focused image by comparing the differences between the image groups using an image algorithm. This technology does not require active laser emission for focal plane measurement, but requires the acquisition of multiple frames of images and the design of an algorithm for focal plane screening, which is time-consuming. Furthermore, the motion mechanism must move along the optical axis during the acquisition of multiple frames, which also poses problems of jitter errors and slow speed. Summary of the Invention

[0004] The first object of the present invention is to provide a microlens array zoom module zoom method, which aims to solve the technical problems of jitter error and slow speed when focusing in existing imaging systems.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A microlens array zoom module zoom method comprises: obtaining a mapping relationship table between a deviation from an objective lens working distance and a microlens array state of the microlens array zoom module; obtaining a laser spot image formed by laser irradiation of an object to be measured, and calculating a position of the object to be measured from a focal plane of the objective lens based on the laser spot image; determining an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured from the focal plane of the objective lens, and comparing the adjustment reference distance with the mapping relationship table to determine the microlens array state of the microlens array zoom module; and generating a focus instruction based on the determined microlens array state to achieve automatic zooming of the microlens array zoom module.

[0007] Preferably, the working distance of the objective lens is defined as the reference point, then the positions deviating from the working distance of the objective lens include 2n+1, the micromirror array states include 2n+1, and the 2n+1 micromirror array states correspond one-to-one to the 2n+1 positions deviating from the working distance of the objective lens.

[0008] Preferably, acquiring a laser spot image formed by laser irradiation of an object to be measured, and calculating the position of the object to be measured to the focal plane of the objective lens based on the laser spot image, includes: acquiring a laser spot image formed by laser irradiation of the object to be measured, and separating the spot in the laser spot image from the background to obtain a spot area image; removing noise from the spot area image by corrosion and expansion to obtain a processed spot area image; extracting a spot contour based on the processed spot area image; calculating a spot edge gradient based on the extracted spot contour, and determining a semicircular direction and radius of the spot according to the calculated spot edge gradient; and obtaining a relative focal plane position of the object based on a linear mapping relationship between the semicircular direction and radius of the spot and a pre-calibrated radius and defocus amount.

[0009] Preferably, determining an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured from the focal plane of the objective lens, and comparing the adjustment reference distance with a mapping relationship table to determine the microlens array state of the microlens array zoom module includes: respectively calculating the absolute values ​​of the differences between the position of the object to be measured from the focal plane of the objective lens and a plurality of deviations from the objective lens working distances; using the deviation from the objective lens working distance corresponding to the smallest absolute value as the adjustment reference distance; and comparing the adjustment reference distance with the mapping relationship table to determine the microlens array state of the microlens array zoom module.

[0010] Preferably, the method of generating a focus instruction based on the determined microlens array state and sending the focus instruction to the MEMS controller so as to adjust the microlens array state of the microlens array zoom module through the MEMS controller to realize automatic zooming of the microlens array zoom module includes: converting the determined microlens array state into an electrical signal and generating a focus instruction according to the electrical signal; sending the focus instruction to the MEMS controller so as to adjust the microlens array state of the microlens array zoom module through the MEMS controller to realize automatic zooming of the microlens array zoom module.

[0011] A second object of the present invention is to provide a microlens array zoom module zoom imaging system, comprising a focal plane measurement unit, a zoom imaging unit, a processor and a MEMS controller, wherein the focal plane measurement unit is connected to the processor, and the MEMS controller is respectively connected to the processor and the microlens array zoom module of the zoom imaging unit, wherein the focal plane measurement unit is used to collect a laser spot image formed by laser irradiation of an object to be measured and transmit the laser spot image to the processor, wherein the processor is used to execute the microlens array zoom module zoom method as described above, and wherein the MEMS controller is used to receive a focus instruction and adjust the microlens array state of the microlens array zoom module according to the focus instruction to realize automatic focusing of the microlens array zoom module.

[0012] Preferably, the focal plane measurement unit includes a detection laser light source, a laser spot camera, a first lens, a second lens, a first beam splitter, a second beam splitter and an objective lens. The detection laser light source emits a laser spot, which passes through the first lens and the first beam splitter. The first beam splitter reflects the laser spot in the direction of the object to be measured, and then passes through the second beam splitter and the objective lens to irradiate the surface of the object to be measured. The surface of the object to be measured forms a laser spot reflected light. The laser spot reflected light passes through the objective lens and is reflected by the second beam splitter, and then passes through the second lens to enter the laser spot camera. The laser spot camera is connected to the processor.

[0013] Preferably, the zoom imaging unit includes a microlens array zoom module, an imaging camera, a coaxial light source and a third beam splitter, a fourth beam splitter, a third lens, a fourth lens and a filter. The coaxial light source emits coaxial illumination light, which passes through the third lens and the third beam splitter. The third beam splitter directs the coaxial illumination light to the direction of the object to be measured, and then irradiates the surface of the object to be measured through the filter, the first beam splitter, the second beam splitter and the objective lens, forming a coaxial illumination light reflection light on the surface of the object to be measured. The coaxial illumination light reflection light passes through the objective lens, the second beam splitter, the first beam splitter, the filter, the third beam splitter and the fourth beam splitter, and then is focused and reflected by the microlens array zoom module to form an imaging reflection light. The imaging reflection light irradiates the fourth beam splitter, the fourth beam splitter reflects the imaging reflection light, and enters the imaging camera through the fourth lens.

[0014] In this scheme, a mapping relationship table between the deviation from the objective lens working distance and the micromirror array state of the microlens array zoom module is pre-constructed, and the focal plane position of the object is obtained in real time in combination with laser focal plane detection technology. The optimal micromirror state is quickly matched through numerical calculation, and then the microlens array zoom module is adjusted using a MEMS controller. No mechanical moving parts are required, and the scheme has the advantages of extremely fast focusing speed, compact and reliable structure, high precision and strong fault tolerance. At the same time, it relies on discrete calibration and table lookup mechanism to reduce computational complexity, can be flexibly adapted to different scenarios, and has great application prospects for automatic focusing and high-definition imaging of complex morphology and deformed objects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0016] Figure 1 This is a flow chart of a microlens array zoom module zoom method provided by an embodiment of the present invention;

[0017] Figure 2 1 is a schematic structural diagram of a zoom imaging system of a microlens array zoom module provided by an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the laser focal plane detection technology provided by an embodiment of the present invention. Description of the drawings:

[0020] 10. Focal plane measurement unit; 11. Detection laser light source; 12. Laser spot camera; 13. First lens; 14. Second lens; 15. First beam splitter; 16. Second beam splitter; 17. Objective lens; 20. Zoom imaging unit; 21. Microlens array zoom module; 22. Imaging camera; 23. Coaxial light source; 24. Third beam splitter; 25. Fourth beam splitter; 26. Third lens; 27. Fourth lens; 28. Filter; 30. Processor; 40. MEMS controller; 50. Object to be measured. DETAILED DESCRIPTION

[0021] The terms "first," "second," "third," "fourth," and so on (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that shown or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, product, or apparatus.

[0022] For ease of understanding, the specific process of the embodiment of the present invention is described below. Figure 1 In an embodiment of the present invention, a microlens array zoom module zoom method includes:

[0023] S101, obtaining a mapping relationship table between deviation from the objective lens working distance and the micro-mirror array state of the micro-lens array zoom module;

[0024] S102, obtaining a laser spot image formed by laser irradiation of the object to be measured, and calculating the position of the object to be measured from the focal plane of the objective lens based on the laser spot image;

[0025] S103, determining an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with a mapping relationship table to determine a microlens array state of the microlens array zoom module;

[0026] S104 : Based on the determined microlens array state, generate a focus instruction to achieve automatic focusing of the microlens array zoom module.

[0027] In this embodiment, in step S101, a mapping relationship table between deviations from the objective lens working distance and the microlens array state of the microlens array zoom module can be pre-constructed, specifically including: obtaining multiple positions that deviate from the objective lens working distance; collecting the microlens array state of the microlens array zoom module corresponding to each position of the calibration object that deviates from the objective lens working distance; establishing a one-to-one mapping relationship between all positions that deviate from the objective lens working distance and the microlens array state of the microlens array zoom module, to obtain a mapping relationship table between positions that deviate from the objective lens working distance and the microlens array state of the microlens array zoom module.

[0028] In this embodiment, the working distance of the objective lens refers to the appropriate distance from the front end of the objective lens to the surface of the observed object. On this basis, a series of positions deviating from the working distance are determined.

[0029] Define the working distance of the objective lens as the reference point, then the positions deviating from the working distance of the objective lens include 2n+1, and the micromirror array states include 2n+1. The 2n+1 micromirror array states correspond to the 2n+1 deviations from the working distance of the objective lens. That is, the focus position deviates from the working distance L of the objective lens by 2n+1 positions, L={L0, L1, ..., L n ,...,L 2n}, the micromirror array state S also corresponds to 2n+1 states, S={S0, S1, ..., S n ,...,S 2n The positive defocus maximum value L0 corresponds to the micromirror state S0; the focus position L n Corresponding micromirror state S n， And L n =0; negative defocus maximum value L 2n Position corresponding state S 2n .

[0030] For example, in this embodiment, five positions are selected that deviate from the working distance of the objective lens. The working distance of the objective lens is set as the reference point. A positive defocus indicates that the object is above the reference point, and a negative defocus indicates that the object is below the reference point. The five positions selected that deviate from the working distance of the objective lens are L0, L1, L2, L3, and L4.

[0031] L0=+20 microns, L0 is the maximum positive defocus value, and L0 is the position of the object 20 microns above the reference point.

[0032] L1=+10 microns, where L1 is the position of the object 10 microns above the reference point.

[0033] L2=0 micron, L2 is the focus position, that is, the working distance of the objective lens.

[0034] L3=-10 microns, where L3 is the object 10 microns below the reference point.

[0035] L4=-20 microns, L4 is the maximum negative defocus value, and L4 is when the object to be measured is 20 microns below the reference point.

[0036] For example, in this embodiment, when collecting the microlens array state of the microlens array zoom module corresponding to each deviation of the calibration object from the objective lens working distance, a standard calibration object, such as a test pattern with a clear texture, is used and placed in sequence at the above-mentioned five positions deviating from the objective lens working distance. Then, by adjusting the state of the microlens array, the imaging achieves optimal clarity, and the microlens array state of the microlens array zoom module corresponding to each position is recorded.

[0037] For example, in this embodiment, the microlens array state of the microlens array zoom module can be described by parameters such as the curvature and tilt angle of each microlens. For simplicity, it is assumed that the microlens array state of each microlens array zoom module is represented by a simple curvature value.

[0038] When the calibration object is located at L0 = +20 microns, the curvature of each microlens in the microlens array is continuously adjusted to achieve the clearest test pattern captured by the microscope. At this point, the curvature value of the microlens array is recorded as S0 = 0.8 (the curvature value here is a relative value and is only used for illustration).

[0039] When the calibration object is located at L1 = +10 μm, use the same method to adjust the microlens array to make the image clear, and record the curvature value of the microlens array as S1 = 0.4.

[0040] When the calibration object is located at L2 = 0 microns, which is the focus position, the microlens array is adjusted to obtain the clearest image, and the curvature value of the microlens array is recorded as S2 = 0 (indicating that the microlens array is in a baseline state without additional curvature adjustment).

[0041] When the calibration object is located at L3=-10 μm: after adjustment, the curvature value of the microlens array is recorded as S3=-0.4.

[0042] When the calibration object is located at L4=-20 μm: after adjustment, the curvature value of the microlens array is recorded as S4=-0.8.

[0043] In this embodiment, the above-obtained deviations from the objective lens working distance and the corresponding microlens array states of the microlens array zoom module are organized into a table to obtain a mapping relationship table between the deviations from the objective lens working distance and the microlens array states. The mapping relationship table is as follows:

[0044]

[0045] In this embodiment, in step S102, Figure 2 As shown in the microlens array zoom module imaging system, a laser spot camera 12 captures the laser spot image formed by laser irradiation of the object to be measured. The laser spot emitted by the detection laser light source 11 passes through the first beam splitter 15, which reflects the laser light in the direction of the object to be measured. After passing through the second beam splitter 16, it illuminates the surface of the object to be measured. After the laser spot is reflected by the object surface, the light is reflected by the second beam splitter 16 and reflected into the laser spot camera 12.

[0046] Among them, the principle of laser focal plane detection technology, such as Figure 3 As shown. After passing through the objective lens, the laser spot is irradiated onto the surface of the object to be measured. During this process, the measured surface and the laser focus plane will present three different relative states: when the measured surface is above the focus plane, this situation is called positive defocus; if the measured surface and the focus plane completely overlap, it is in focus; and when the measured surface is below the focus plane, it is negative defocus. When a semicircular laser beam is used, the different relative states of the measured surface and the focus plane correspond to different laser spot shapes. When positively defocused, the spot is in the right semicircle; when focused, the spot is a small dot; when negatively defocused, the spot is in the left semicircle. It is worth noting that the spot radius and the defocus amount are linearly related, and the larger the radius, the greater the defocus amount. Based on this, the imaging sensor only needs to detect the shape and size of the spot to accurately determine the position of the measured surface relative to the focus plane, that is, the direction and distance.

[0047] In this embodiment, a laser spot image formed by laser irradiating an object to be measured is obtained, and based on the laser spot image, a position of the object to be measured relative to the focal plane of the objective lens is calculated, including: obtaining a laser spot image formed by laser irradiating the object to be measured, and separating the spot in the laser spot image from the background to obtain a spot area image; removing noise from the spot area image by corrosion and expansion to obtain a processed spot area image; extracting a spot contour based on the processed spot area image; calculating a spot edge gradient based on the extracted spot contour, and determining a semicircular direction and radius of the spot according to the calculated spot edge gradient; and obtaining a relative focal plane position of the object based on a mapping relationship between the semicircular direction and radius of the spot and a pre-calibrated radius and defocus amount.

[0048] In this embodiment, the light spot is separated from the background by means of threshold segmentation, difference method, etc., to obtain a light spot area image.

[0049] In this embodiment, the light spot boundary is obtained by using algorithms such as Canny edge detection and contour tracking.

[0050] In this embodiment, a laser spot (such as a Gaussian beam or a circular spot) may exhibit an elliptical or semicircular shape when defocused (depending on the optical path design). The gradient direction determines the direction of the spot deformation (such as the major axis), and the defocus amount is calculated in combination with the radius. For example, in laser triangulation, the greater the defocus amount, the larger the projected size of the spot on the detector. Calibration can establish a linear mapping between radius and defocus amount (e.g., r = 5 pixels corresponds to +10 μm), thereby obtaining the object's relative focal plane position d.

[0051] For example: If a right semicircular spot is detected, the radius corresponds to d = +15 μm, and the object is 15 μm above the focal plane.

[0052] In this embodiment, in step S103, an adjustment reference distance of the microlens array zoom module is determined based on the position of the object to be measured from the focal plane of the objective lens, and the adjustment reference distance is compared with a mapping relationship table to determine the microlens array state of the microlens array zoom module. Specifically, the steps include: calculating the absolute values ​​of the differences between the position of the object to be measured from the focal plane of the objective lens and a plurality of deviations from the objective lens working distances; using the deviation from the objective lens working distance corresponding to the smallest absolute value as the adjustment reference distance; and comparing the adjustment reference distance with the mapping relationship table to determine the microlens array state of the microlens array zoom module.

[0053] In this embodiment, the absolute difference is calculated: for each calibration distance L i , calculate R i =|dL i ∣.

[0054] Example: If d = +15μm, and the calibration distances are -20μm, -10μm, 0μm, +10μm, +20μm, then: R0 = 5μm, R1 = 5μm, R2 = 15μm, R3 = 25μm, R4 = 35μm.

[0055] If there are multiple identical minimum values ​​(e.g., R0=R1=5μm), the historical adjacent state is prioritized (e.g., selecting L1=+10μm to avoid curvature jumps).

[0056] Finally, the micromirror array state is obtained from the mapping relationship table according to L1 (e.g., L1=+10μm→S1=0.4).

[0057] In this embodiment, in step S104, a focus instruction is generated based on the determined microlens array state. Specifically, the microlens array state of the microlens array zoom module (e.g., the curvature value of each micromirror) is converted into an electrical signal and sent to the MEMS controller. The MEMS controller independently adjusts the tilt angle or curvature of each micromirror so that the entire array fits the corresponding curved surface (e.g., an upward curvature of 0.4). The MEMS drive response speed reaches 12 kHz, and a single focus adjustment takes approximately 83 μs, which is much faster than traditional mechanical zoom (hundreds of milliseconds).

[0058] In this embodiment, a mapping relationship table between the deviation from the objective lens working distance and the micromirror array state of the microlens array zoom module is pre-constructed, and the focal plane position of the object is obtained in real time in combination with laser focal plane detection technology. The optimal micromirror state is quickly matched through numerical calculation, and then the microlens array zoom module is adjusted using a MEMS controller. No mechanical moving parts are required, and the method has the advantages of extremely fast focusing speed, compact and reliable structure, high precision and strong fault tolerance. At the same time, it relies on discrete calibration and table lookup mechanisms to reduce computational complexity, can be flexibly adapted to different scenarios, and has great application prospects for automatic focusing and high-definition imaging of complex morphologies and deformed objects.

[0059] An embodiment of the present invention also provides a zoom imaging system of a microlens array zoom module 21, including a focal plane measurement unit 10, a zoom imaging unit 20, a processor 30 and a MEMS controller 40. The focal plane measurement unit 10 is connected to the processor 30, and the MEMS controller 40 is respectively connected to the processor 30 and the microlens array zoom module 21 of the zoom imaging unit 20. The focal plane measurement unit 10 is used to collect a laser spot image formed by laser irradiation of an object to be measured 50, and transmit the laser spot image to the processor 30. The processor 30 is used to execute the zoom method of the microlens array zoom module 21 as described above. The MEMS controller 40 is used to receive a focus instruction and adjust the microlens array state of the microlens array zoom module 21 according to the focus instruction to realize automatic focusing of the microlens array zoom module 21.

[0060] In this embodiment, the focal plane measurement unit 10 includes a detection laser light source 11, a laser spot camera 12, a first lens 13, a second lens 14, a first beam splitter 15, a second beam splitter 16, and an objective lens 17. The detection laser light source 11 emits a laser spot, which passes through the first lens 13 and the first beam splitter 15. The first beam splitter 15 reflects the laser spot in the direction of the object 50 to be measured, and then passes through the second beam splitter 16 and the objective lens 17 to irradiate the surface of the object 50 to be measured. The surface of the object 50 to be measured forms a laser spot reflection light. The laser spot reflection light passes through the objective lens 17 and is reflected by the second beam splitter 16. Then, it passes through the second lens 14 and enters the second laser spot camera 12.

[0061] In this embodiment, the zoom imaging unit 20 includes a microlens array zoom module 21, an imaging camera 22, a coaxial light source 23, a third beam splitter 24, a fourth beam splitter 25, a third lens 26, a fourth lens 27, and a filter 28. The coaxial light source 23 emits coaxial illumination light, which passes through the third lens 26 and the third beam splitter 24. The third beam splitter 24 directs the coaxial illumination light to the direction of the object to be measured 50, and then passes through the filter 28, the first beam splitter 15, the second beam splitter 16, and the objective lens 1. 7 is irradiated onto the surface of the object to be measured 50, and the surface of the object to be measured 50 forms a coaxial illumination light reflection light. The coaxial illumination light reflection light passes through the objective lens 17, the second beam splitter 16, the first beam splitter 15, the filter 28, the third beam splitter 24 and the fourth beam splitter 25, and then is focused and reflected by the microlens array zoom module 21 to form an imaging reflection light. The imaging reflection light is irradiated by the fourth beam splitter 25, and the fourth beam splitter 25 reflects the imaging reflection light and enters the imaging camera 22 through the fourth lens 27.

[0062] In this embodiment, after the micro-mirror array of the micro-lens array zoom module 21 is adjusted to a focusing state, the objective lens 17 and the micro-lens array zoom module 21 cooperate to focus the object light on the photosensitive surface of the imaging camera 22 to capture a clear image.

[0063] In this embodiment, a mapping relationship table between the working distance of the deviation objective lens 17 and the micromirror array state of the microlens array zoom module 21 is pre-constructed, and the focal plane position of the object is obtained in real time in combination with laser focal plane detection technology. The optimal micromirror state is quickly matched through numerical calculation, and then the MEMS controller 40 is used to adjust the microlens array zoom module 21. Finally, no mechanical moving parts are required, and the system has the advantages of extremely fast focusing speed, compact and reliable structure, high precision and strong fault tolerance. At the same time, it relies on discrete calibration and table lookup mechanism to reduce computational complexity, can be flexibly adapted to different scenarios, and has great application prospects for automatic focusing and high-definition imaging of complex morphology and deformed objects.

[0064] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present description and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A microlens array zoom module zoom method, characterized in that: include: Obtaining a mapping relationship table between the deviation from the objective lens working distance and the micro-mirror array state of the micro-lens array zoom module; Acquire a laser spot image formed by laser irradiation of the object to be measured, and calculate the position of the object to be measured to the focal plane of the objective lens based on the laser spot image; Determining an adjustment reference distance of the microlens array zoom module based on the position of the object to be measured to the focal plane of the objective lens, and comparing the adjustment reference distance with a mapping relationship table to determine a microlens array state of the microlens array zoom module; Based on the determined microlens array state, a focus instruction is generated to realize automatic focusing of the microlens array zoom module; The method comprises determining an adjustment reference distance of a microlens array zoom module based on a position of an object to be measured from a focal plane of an objective lens, and comparing the adjustment reference distance with a mapping relationship table to determine a microlens array state of the microlens array zoom module, comprising: respectively calculating absolute values ​​of differences between a position of the object to be measured from a focal plane of an objective lens and a plurality of deviations from the objective lens working distance; using the deviation from the objective lens working distance corresponding to the smallest absolute value as an adjustment reference distance; comparing the adjustment reference distance with the mapping relationship table to determine a microlens array state of the microlens array zoom module; and selecting a historical adjacent state if multiple identical smallest absolute values ​​exist; The method generates a focus instruction based on the determined microlens array state, and sends the focus instruction to the MEMS controller, so as to adjust the microlens array state of the microlens array zoom module through the MEMS controller to achieve automatic zooming of the microlens array zoom module, including: converting the determined microlens array state into an electrical signal, and generating a focus instruction according to the electrical signal; and sending the focus instruction to the MEMS controller, so as to adjust the microlens array state of the microlens array zoom module through the MEMS controller to achieve automatic zooming of the microlens array zoom module.

2. The microlens array zoom module zoom method according to claim 1, wherein: Define the working distance of the objective lens as the reference point, then the positions deviating from the working distance of the objective lens include 2n+1, the micromirror array states include 2n+1, and the 2n+1 micromirror array states correspond one-to-one to the 2n+1 deviations from the working distance of the objective lens.

3. The microlens array zoom module zoom method according to claim 1, wherein: The step of acquiring a laser spot image formed by irradiating the object to be measured with laser light and calculating the position of the object to be measured from the focal plane of the objective lens based on the laser spot image comprises: Acquire a laser spot image formed by laser irradiation of the object to be measured, and separate the spot in the laser spot image from the background to obtain a spot area image; removing noise from the light spot area image by erosion and expansion to obtain a processed light spot area image; extracting a light spot contour based on the processed light spot area image; Based on the extracted spot profile, the spot edge gradient is calculated, and the semicircular direction and radius of the spot are determined according to the calculated spot edge gradient; The relative focal position of the object is obtained based on the semicircular direction and radius of the light spot and the pre-calibrated linear mapping relationship between the radius and the defocus amount.

4. A microlens array zoom module zoom imaging system, characterized in that: The invention comprises a focal plane measurement unit, a zoom imaging unit, a processor and a MEMS controller, wherein the focal plane measurement unit is connected to the processor, and the MEMS controller is respectively connected to the processor and the microlens array zoom module of the zoom imaging unit. The focal plane measurement unit is used to collect a laser spot image formed by laser irradiation of an object to be measured and transmit the laser spot image to the processor. The processor is used to execute the microlens array zoom module zoom method according to any one of claims 1 to 3. The MEMS controller is used to receive a focus instruction and adjust the microlens array state of the microlens array zoom module according to the focus instruction to realize automatic focusing of the microlens array zoom module.

5. The microlens array zoom module zoom imaging system according to claim 4, wherein: The focal plane measurement unit includes a detection laser light source, a laser spot camera, a first lens, a second lens, a first beam splitter, a second beam splitter and an objective lens. The detection laser light source emits a laser spot, which passes through the first lens and the first beam splitter. The first beam splitter reflects the laser spot in the direction of the object to be measured, and then passes through the second beam splitter and the objective lens to irradiate the surface of the object to be measured. The surface of the object to be measured forms a laser spot reflected light. The laser spot reflected light passes through the objective lens and is reflected by the second beam splitter, and then passes through the second lens to enter the laser spot camera. The laser spot camera is connected to the processor.

6. The microlens array zoom module zoom imaging system according to claim 5, wherein: The zoom imaging unit includes a microlens array zoom module, an imaging camera, a coaxial light source and a third beam splitter, a fourth beam splitter, a third lens, a fourth lens and a filter. The coaxial light source emits coaxial illumination light, which passes through the third lens and the third beam splitter. The third beam splitter directs the coaxial illumination light to the direction of the object to be measured, and then irradiates the surface of the object to be measured through the filter, the first beam splitter, the second beam splitter and the objective lens, forming a coaxial illumination light reflection light on the surface of the object to be measured. The coaxial illumination light reflection light passes through the objective lens, the second beam splitter, the first beam splitter, the filter, the third beam splitter and the fourth beam splitter, and then is focused and reflected by the microlens array zoom module to form an imaging reflection light. The imaging reflection light irradiates the fourth beam splitter, the fourth beam splitter reflects the imaging reflection light, and then enters the imaging camera through the fourth lens.

Images