An auto-focusing method and system for a high-resolution objective

Abstract

The application relates to the technical field of optical lenses, and discloses an automatic focusing method and system of a high-resolution objective lens, which comprises coarse adjustment and fine adjustment. In the application, when the edge contrast exceeds a reasonable range, the influence degree of the sample display image is judged according to the super process degree, the judgment is divided into multiple stages, the fine adjustment focusing knob is judged whether to be adjusted back in each stage, and in the process, a noise point judgment mechanism is introduced in a stage which is not good to judge, if the noise point is not within the standard, the stage is not adjusted back, so that the judgment process is more practical, the numerical influence and the actual use are comprehensively considered, and the application has more use significance.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, specifically to an autofocus method and system for a high-resolution objective lens. Background Technology

[0002] High-resolution objectives refer to microscope objectives with high numerical aperture and optical performance. Numerical aperture is an important parameter of the objective, affecting its ability to focus light and the smallest details it can resolve.

[0003] When observing samples using an objective lens, focusing is essential for a clear view. First, select the appropriate objective lens based on the magnification. Then, place the sample on a slide and cover it with a coverslip. Ensure the sample is centered within the microscope's field of view, avoiding air bubbles. Perform coarse adjustments first, ensuring the entire sample is visible under the lens, followed by fine adjustments to achieve a sharp image. This process requires continuous adjustments and tests the operator's experience and observational skills. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide an autofocus method and system for high-resolution objectives, which enables automatic focusing of the objectives.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an autofocus method for a high-resolution objective lens, comprising: Step 1, driving a coarse adjustment knob with a displacement motor to bring the objective lens closer to the sample, and simultaneously acquiring the distance between the center point of the objective lens and the center point of the sample using a sensor, recording this distance as a basis for subsequent judgment; Step 2, setting a distance threshold based on the maximum acceptable distance between the center point of the objective lens and the center point of the sample, and treating samples whose distance between the center point of the objective lens and the center point of the sample does not exceed the distance threshold as if they were located at the center of the objective lens; Step 3, comparing the distance with the distance threshold, if the distance is less than or equal to the distance threshold, it indicates that the error between the center point of the sample and the center point of the objective lens is small, and the sample can be considered as if it were located at the center of the objective lens. In this case, the sensor acquires an image of the sample. If a blank area of ​​a glass slide appears around the sample in the image, the next step can be performed; if no glass slide appears... In the blank area, continue adjusting the coarse focus knob until a blank area appears on the slide. If the distance is greater than the distance threshold, it indicates a large error between the sample center point and the objective lens center point. In this case, continue adjusting the coarse focus knob until the distance is less than or equal to the distance threshold. Step four: After obtaining a completely complete image of the sample, adjust the fine focus knob using the displacement motor. At the same time, obtain the maximum and minimum brightness values ​​at the edge of the sample image. Subtract the minimum brightness value from the maximum brightness value to obtain the edge contrast. In addition, set the edge contrast threshold according to the parameter information and compare the edge contrast with the edge contrast threshold. If the edge contrast is greater than or equal to the edge contrast threshold, it indicates that the sample image is clear. At this point, stop adjusting. If the edge contrast is less than the edge contrast threshold, it indicates that the image is not clear enough. In this case, continue adjusting the fine focus knob until the edge contrast is greater than or equal to the edge contrast threshold.

[0006] In some implementations, when the edge contrast is greater than or equal to the edge contrast threshold, a second threshold range for edge contrast with a minimum value greater than the edge contrast threshold is set, and the edge contrast is compared with the second threshold range for edge contrast. Different responses are then derived based on the comparison results.

[0007] In some implementations, if the edge contrast falls within the second threshold range of edge contrast, it means that the edge contrast is within a reasonable range. If the edge contrast is less than the minimum value of the second threshold range of edge contrast, it means that the edge contrast can be further improved. At this time, the user can choose whether to continue to fine-tune it to a reasonable range according to their own needs. If the edge contrast is greater than the maximum value of the second threshold range of edge contrast, it means that the edge contrast exceeds the reasonable range. In this case, the fine-tuning focus knob is called back.

[0008] In some implementations, when the edge contrast exceeds the maximum value of the second threshold range of edge contrast, the degree of impact of the edge contrast exceeding the threshold on the sample display image is used to determine whether the fine-tuning focus knob should be reverted.

[0009] In some implementations, the specific method for determining whether to revert the fine-tuning focus knob based on the degree of impact of the edge contrast exceeding the reasonable range is as follows: different levels of impact are defined according to how much the edge contrast exceeds the reasonable range. When the edge contrast exceeds the reasonable range by less than 10%, the impact on the sample display image is defined as a first-level impact. When the edge contrast exceeds the reasonable range by 10%-20%, the impact on the sample display image is defined as a second-level impact. When the edge contrast exceeds the reasonable range by more than 20%, the impact on the sample display image is defined as a third-level impact. Under the first-level impact, the edge contrast exceeding the reasonable range is considered low, and the impact on the sample display image is low. In this case, the fine-tuning focus knob is not reverted. Under the third-level impact, the edge contrast exceeding the reasonable range is considered high, and the impact on the sample display image is high. In this case, the fine-tuning focus knob is reverted. Under the second-level impact, the edge contrast exceeding the reasonable range is considered moderate, and the impact on the sample display image is moderate. In this case, whether the fine-tuning focus knob should be reverted requires further judgment.

[0010] In some implementations, a further judgment is made by acquiring the pixel values ​​of all pixels in the sample display image through a sensor, setting a pixel value range threshold according to the normal range, comparing the pixel value of each pixel with the pixel value range threshold, and taking different actions based on the comparison results.

[0011] In some implementations, if a pixel value falls within a pixel value range threshold, the pixel is identified as an abnormal pixel; if a pixel value does not fall within a pixel value range threshold, the pixel is identified as a normal pixel. The number of abnormal pixels is recorded, and the number of abnormal pixels is the noise quantity. A noise quantity threshold is set according to requirements, and the noise quantity is compared with the noise quantity threshold. Different responses are derived based on the comparison results.

[0012] In some implementations, if the number of noise points is less than or equal to the noise number threshold, it means that the noise number meets the standard. In this case, the fine-tuning focus knob will not be turned back for secondary effects. If the number of noise points is greater than the noise number threshold, it means that the noise number does not meet the standard. In this case, the fine-tuning focus knob will be turned back for secondary effects.

[0013] This invention also provides the following technical solutions:

[0014] This invention further provides an autofocus system for a high-resolution objective lens, comprising: a coarse adjustment module, which drives a coarse adjustment knob via a displacement motor to bring the objective lens closer to the sample; simultaneously, it acquires the distance between the center point of the objective lens and the center point of the sample via a sensor; and sets a distance threshold, comparing the distance with the distance threshold. If the distance is less than or equal to the distance threshold, it indicates that the error between the center point of the sample and the center point of the objective lens is small, and the sample can be considered equivalent to being located at the center of the objective lens. In this case, the sensor acquires an image of the sample. If a blank area of ​​a slide appears around the sample in the image, the next step can be performed; if no blank area of ​​a slide appears, the coarse adjustment knob continues to be adjusted until a blank area of ​​a slide appears. If the distance is greater than the distance threshold, it indicates that the sample... If the error between the center point of the sample image and the center point of the objective lens is large, continue adjusting the coarse focus knob until the distance is less than or equal to the distance threshold. The fine focus module is used to adjust the fine focus knob by driving the fine focus knob through the displacement motor. At the same time, it obtains the maximum and minimum brightness values ​​at the edge of the sample image. The edge contrast is obtained by subtracting the minimum brightness value from the maximum brightness value. In addition, an edge contrast threshold is set according to the parameter information. The edge contrast is compared with the edge contrast threshold. If the edge contrast is greater than or equal to the edge contrast threshold, it means that the sample image is clear. At this time, the adjustment is stopped. If the edge contrast is less than the edge contrast threshold, it means that the image is not clear enough. In this case, continue adjusting the fine focus knob until the edge contrast is greater than or equal to the edge contrast threshold.

[0015] The present invention further provides a computer-readable storage medium storing a computer program that is executed by a processor to implement the above-described method for autofocusing a high-resolution objective lens.

[0016] The technical solution provided by this invention has the following advantages compared with the prior art:

[0017] Firstly, in this invention, the factors for successful coarse adjustment are divided into two categories: whether the distance between the objective lens center point and the sample center point meets the standard, and whether there is a blank area around the sample. Only when both of these conditions are met is the coarse adjustment considered successful. Based on this, in fine adjustment, edge contrast is calculated using edge brightness, and the edge contrast is used to represent image sharpness for adjustment. This method combines distance error, edge contrast, and a feedback mechanism, enabling the objective lens to automatically focus and obtain a clear image.

[0018] Secondly, in this invention, when the edge contrast exceeds a reasonable range, the degree of impact on the sample display image is judged according to the degree of excess, and the fine adjustment focus knob is reverted at each level. In addition, a noise judgment mechanism is introduced in the level that is difficult to judge. If the noise is not within the standard, no revert is made at this level, so that the judgment process is more practical, and the numerical impact and actual use are taken into account, making it more meaningful to use. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the logical steps of the present invention;

[0020] Figure 2 This is a schematic diagram of the module structure of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0023] The autofocus method for high-resolution objectives provided by this invention, such as... Figure 1 and Figure 2 As shown, it includes:

[0024] The first step, using manual focusing on the objective lens, is to slowly move the objective lens towards the sample using the coarse focus knob until the sample appears in the field of view. Once the sample is in the field of view, the fine focus knob is used for fine focusing to make the image clearer. Based on this, we can summarize that the purpose of using the coarse focus knob is to first ensure the sample appears in the field of view; it is sufficient that the entire sample appears without omission from the lens, and the image does not need to be extremely clear. Then, the fine focus knob is used for fine adjustment to make the image clear. The best way to ensure the sample is completely in the field of view is to align the center point of the sample with the center point of the lens. This ensures the sample is centered within the lens. Under this premise, ensuring that the blank area of ​​the slide appears in the lens indicates that the sample is completely in the lens's field of view without omission. Based on the above, firstly, the coarse focus knob is driven by a displacement motor to move the objective lens closer to the sample. Simultaneously, the distance between the center point of the objective lens and the center point of the sample is acquired by a sensor and recorded for subsequent judgment.

[0025] The second step involves setting a distance threshold based on the impact of the error between the objective lens center point and the sample center point on the complete image of the sample. This distance threshold represents the maximum acceptable distance; if the distance between the objective lens center point and the sample center point exceeds this threshold, the sample cannot be considered to be centered on the objective lens. If the distance between the objective lens center point and the sample center point does not exceed the distance threshold, the sample can be considered to be centered on the objective lens. This is because the sample is only completely centered on the objective lens when the distance between the objective lens center point and the sample center point is zero. However, in practical applications, as long as the error is small, the sample can be considered to be centered on the objective lens.

[0026] The third step involves comparing the distance with a distance threshold and determining the appropriate action based on the comparison result. If the distance is less than or equal to the distance threshold, it indicates that the error between the sample center point and the objective lens center point is small, and the sample can be considered equivalent to being located at the center of the objective lens. In this case, the sample image is acquired again using the sensor. If a blank area of ​​the slide appears around the sample in the sample image, the next step can be performed; if no blank area of ​​the slide appears, the coarse focus knob is adjusted until a blank area of ​​the slide appears. If the distance is greater than the distance threshold, it indicates that the error between the sample center point and the objective lens center point is large. In this case, the coarse focus knob is adjusted until the distance is less than or equal to the distance threshold.

[0027] The fourth step involves coarsely adjusting the objective lens in the first three steps to obtain a complete image of the sample. Then, a fine-tuning focus knob is adjusted using a displacement motor. Simultaneously, the maximum and minimum brightness values ​​at the edges of the sample image are acquired via a sensor. The edge contrast is calculated by subtracting the minimum brightness value from the maximum. Additionally, an edge contrast threshold is set based on parameter information. This threshold represents the minimum edge contrast required for a sharp image. For example, the edge contrast threshold might be 20 gray levels. Edge contrast reflects the sharpness of object edges in an image. In microscopes or photographic equipment, when object edges are too blurry, image details are blurred, resulting in low contrast. A sharp image typically exhibits rapid edge transitions, meaning the transition between bright and dark areas is very distinct, forming clear edges. High edge contrast indicates significant changes in brightness and darkness in the image, clearly distinguishing object boundaries, and usually represents accurate focus. Low edge contrast, on the other hand, indicates smooth edge transitions in the image, suggesting inaccurate focus or poor image quality. Therefore, by measuring the brightness difference at the image edges (the difference between the maximum and minimum brightness values), we can determine if the image is sharp and ensure that the focus is at its optimal position. Based on this, the edge contrast is compared with an edge contrast threshold, and different actions are taken according to the comparison results. If the edge contrast is greater than or equal to the edge contrast threshold, it means that the sample image is already sharp, and adjustment is stopped. If the edge contrast is less than the edge contrast threshold, it means that the image is not sharp enough. In this case, continue adjusting the fine-tuning focus knob until the edge contrast is greater than or equal to the edge contrast threshold.

[0028] The autofocus method for high-resolution objectives described above combines coarse and fine focusing steps, achieving automatic adjustment through sensors and feedback mechanisms to ensure image sharpness. First, the objective is brought close to the sample using the coarse focusing knob until the sample enters the field of view, and the distance between the center point of the objective and the center point of the sample is recorded by the sensor. Then, the distance is compared with a set distance threshold to determine if the sample is centered on the objective. If the error is small and there is a blank area of ​​the slide in the image, it indicates that the sample is fully in the field of view, and the process continues to the fine focusing stage. If the error is large, the coarse focusing knob is adjusted until the error is less than or equal to the distance threshold. Next, fine adjustments are made using the fine focusing knob, and the maximum and minimum brightness values ​​of the image edges are measured by the sensor to calculate edge contrast. Edge contrast reflects the sharpness of the image edges; high contrast means a sharp image and accurate focus, while low contrast indicates inaccurate focus. By comparing with a preset edge contrast threshold, if the edge contrast is greater than or equal to the threshold, the image is sufficiently sharp, and adjustment stops; if it is lower than the threshold, the fine focusing knob is adjusted until the image is sharp. This method combines distance error, image sharpness, and a feedback mechanism to ensure that high-resolution objectives can autofocus and acquire sharp images.

[0029] In the above process, when the edge contrast is greater than or equal to the edge contrast threshold, it indicates that the sample image is clear. However, it is important to note that the edge contrast should not be too high. While high edge contrast usually means a clear image, excessive edge contrast may indicate over-enhancement or artifacts, affecting the image's realism and detail. Excessively high edge contrast is often caused by over-sharpening or over-focusing, which can lead to abrupt edges, unnatural transitions between light and dark areas, and even halos or noise, compromising the image's realism and fine details. Especially in microscopic images, excessively high edge contrast can exaggerate the edges of microscopic structures such as cells and tissues, distorting details and obscuring the sample's true morphology and structure. Ideally, edge contrast should clearly present image edges while avoiding unrealistic effects caused by excessive contrast enhancement. Therefore, edge contrast should not be too high and must be kept within a reasonable range to ensure the image is both clear and possesses realistic details, avoiding image artifacts caused by over-sharpening, and guaranteeing the accuracy of analysis and the true presentation of sample characteristics. Based on this, a second threshold range for edge contrast is set. The minimum value of this second threshold range must be greater than the initial edge contrast threshold. For example, the second threshold range might be 21-35 gray levels, representing a reasonable range for clear and realistic edge contrast in an image. After setting the second threshold range, the edge contrast is compared to this range, and different actions are taken based on the comparison results. If the edge contrast falls within the second threshold range, it means the edge contrast is within a reasonable range. If the edge contrast is less than the minimum value of the second threshold range, it means the edge contrast has reached the minimum standard for clarity, but it can be further improved to enhance sharpness. In this case, the user can choose whether to continue fine-tuning to a reasonable range or maintain the current state. If the edge contrast is greater than the maximum value of the second threshold range, it means the edge contrast exceeds a reasonable range. In this case, the focus knob is retracted to reduce the edge contrast to within the second threshold range. In summary, when the edge contrast is greater than or equal to the set edge contrast threshold, it indicates that the image has reached a clear standard. However, edge contrast should not be too high, as excessive contrast can lead to over-sharpening or artifacts, compromising the realism and detail of the image. This is especially true in microscopic images, where excessively high edge contrast can make the edges of microscopic structures such as cells and tissues appear too abrupt, losing precise detail. Therefore, the ideal edge contrast should be maintained within a reasonable range to ensure that the image is both sharp and realistic. To this end, a second threshold range for edge contrast has been established, representing a reasonable range for edge contrast in the image.If the edge contrast falls within this range, it indicates that the image has achieved a balance between sharpness and realism. If the contrast is below the minimum value of the range, it means that the image sharpness can be further improved, and the user can choose to continue adjusting. If the contrast exceeds the maximum value of the range, it indicates that the image contrast is too high, and it needs to be restored to a reasonable range by adjusting the fine-tuning focus knob to ensure the accuracy and realism of the image.

[0030] As mentioned above, excessively high edge contrast can lead to image distortion, sharpening, and noise. However, the specific effects are unpredictable, and the extent of the impact on image display cannot be assessed. Therefore, when the edge contrast exceeds the maximum value of the second threshold range, theoretically, adjusting the focus knob should be used to reduce the edge contrast back to within the second threshold range. However, on the one hand, the degree of adjustment when adjusting the focus knob cannot be precisely controlled; it might adjust back to the second threshold range, or it might adjust back to the minimum value below the second threshold range, or even below the threshold. On the other hand, the degree to which the edge contrast exceeds the maximum value of the second threshold range affects the displayed image differently, and adjustment may not always be necessary. Therefore, when the edge contrast exceeds the maximum value of the second threshold range, the following method is used to determine whether to adjust the focus knob. Specifically, the degree of impact is defined based on how much the edge contrast exceeds a reasonable range (the second threshold range for edge contrast). When the edge contrast exceeds the reasonable range by less than 10%, the impact on the sample image is defined as Level 1 impact. When the edge contrast exceeds the reasonable range by 10%-20%, the impact on the sample image is defined as Level 2 impact. When the edge contrast exceeds the reasonable range by more than 20%, the impact on the sample image is defined as Level 3 impact. Under Level 1 impact, the edge contrast exceeding the reasonable range is considered low, and the impact on the sample image is low; in this case, the fine-tuning focus knob is not turned back. Under Level 3 impact, the edge contrast exceeding the reasonable range is considered high, and the impact on the sample image is high; in this case, the fine-tuning focus knob is turned back. Under Level 2 impact, the edge contrast exceeding the reasonable range is considered moderate, and the impact on the sample image is moderate; in this case, whether the fine-tuning focus knob should be turned back requires further judgment. Further judgment is made as follows: Pixel values ​​of all pixels in the sample display image are acquired via a sensor. A pixel value range threshold is set based on the normal range. The pixel value of each pixel is compared to the threshold. If the pixel value falls within the threshold, it is considered an abnormal pixel; otherwise, it is considered a normal pixel. The number of abnormal pixels is recorded; this number represents the noise level. A noise level threshold is set according to requirements, and the noise level is compared to the threshold. Different actions are taken based on the comparison results. If the noise level is less than or equal to the threshold, it means the noise level meets the standard. In this case, for secondary effects, the fine-tuning focus knob is not turned back. If the noise level is greater than the threshold, it means the noise level does not meet the standard. In this case, for secondary effects, the fine-tuning focus knob is turned back.In general, when edge contrast exceeds a reasonable range, images may exhibit distortion, sharpening, and noise, but the degree of impact is uncertain. Therefore, if edge contrast exceeds the maximum value of the second threshold range, the contrast can be adjusted by fine-tuning the focus knob. However, since the adjustment function cannot be precisely controlled, and different degrees of excess have varying impacts on the image, a simple adjustment is not feasible. Therefore, an impact level is set for edge contrast exceeding the threshold: Level 1 impact (less than 10%), no adjustment; Level 2 impact (10%-20%), moderate impact, requiring further assessment; and Level 3 impact (exceeding 20%), significant impact, requiring adjustment. For Level 2 impact, pixel values ​​are obtained from the sensor to determine if each pixel is within the normal range, thus calculating the noise level. If the noise level is less than or equal to the threshold, no adjustment is made; if it exceeds the threshold, fine-tuning the focus knob is activated. This method intelligently determines whether to adjust the focus knob by comprehensively considering edge contrast and noise level, ensuring image quality optimization.

[0031] The processes described above with reference to the flowcharts in the embodiments disclosed in this invention can be implemented as computer software programs. Embodiments of this invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by a central processing unit, it performs the functions defined in the methods of this application. It should be noted that the computer-readable medium described above in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection having one or more wire segments, a portable computer disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless segments, wire segments, optical cables, RF, etc., or any suitable combination thereof.

[0032] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0033] Those skilled in the art should understand that the above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. An autofocusing method for a high-resolution objective lens, characterized in that, include: Step 1: Drive the coarse adjustment knob with the displacement motor to bring the objective lens closer to the sample. At the same time, obtain the distance between the center point of the objective lens and the center point of the sample through the sensor, and record this distance to make subsequent judgments. Step 2: Set a distance threshold based on the maximum acceptable distance between the objective lens center point and the sample center point. Samples whose distance between the objective lens center point and the sample center point does not exceed the distance threshold are considered as being located at the center of the objective lens. Step 3: Compare the distance with the distance threshold. If the distance is less than or equal to the distance threshold, it means that the error between the sample center point and the objective lens center point is small. The sample can be regarded as being located at the center of the objective lens. In this case, the sample image is then acquired by the sensor. If a blank area of ​​the glass slide appears around the sample in the sample image, the next step can be carried out. If no blank area appears on the slide, continue adjusting the coarse focus knob until a blank area appears on the slide. If the distance is greater than the distance threshold, it means that the error between the sample center point and the objective lens center point is large. In this case, continue adjusting the coarse focus knob until the distance is less than or equal to the distance threshold. Step four: After obtaining a complete image of the sample, adjust the fine-tuning focus knob using the displacement motor. Simultaneously, acquire the maximum and minimum brightness values ​​at the edges of the sample image. Subtract the minimum brightness value from the maximum brightness value to obtain the edge contrast. Additionally, set the edge contrast threshold according to the parameter information and compare the edge contrast with the edge contrast threshold. If the edge contrast is greater than or equal to the edge contrast threshold, it indicates that the sample image is clear, and adjustment is stopped. If the edge contrast is less than the edge contrast threshold, it indicates that the image is not clear enough. In this case, continue adjusting the fine-tuning focus knob until the edge contrast is greater than or equal to the edge contrast threshold.

2. The autofocus method for a high-resolution objective lens according to claim 1, characterized in that, When the edge contrast is greater than or equal to the edge contrast threshold, a second threshold range for edge contrast with a minimum value greater than the edge contrast threshold is set. The edge contrast is compared with the second threshold range for edge contrast, and different responses are given based on the comparison results.

3. The autofocus method for a high-resolution objective lens according to claim 2, characterized in that, If the edge contrast falls within the second threshold range, it means the edge contrast is within a reasonable range. If the edge contrast is less than the minimum value of the second threshold range, it means the edge contrast can be further improved. At this point, the user can choose whether to continue fine-tuning to a reasonable range according to their needs. If the edge contrast is greater than the maximum value of the second threshold range, it means the edge contrast exceeds a reasonable range. In this case, the focus knob should be reverted to its previous state.

4. The autofocus method for a high-resolution objective lens according to claim 3, characterized in that, When the edge contrast exceeds the maximum value of the second threshold range, the degree of impact of the edge contrast exceeding the threshold on the sample display image determines whether the fine-tuning focus knob should be reverted.

5. The autofocus method for a high-resolution objective lens according to claim 4, characterized in that, The specific method for determining whether to adjust the fine-tuning focus knob based on the degree to which edge contrast exceeds the reasonable range is as follows: Different levels of influence are defined based on how much the edge contrast exceeds the reasonable range. When the edge contrast exceeds the reasonable range by less than 10%, the influence on the sample image is defined as Level 1 influence. When the edge contrast exceeds the reasonable range by 10%-20%, the influence on the sample image is defined as Level 2 influence. When the edge contrast exceeds the reasonable range by more than 20%, the influence on the sample image is defined as Level 3 influence. Under Level 1 influence, the edge contrast exceeding the reasonable range is considered low, and the influence on the sample image is low; in this case, the fine-tuning focus knob is not adjusted. Under Level 3 influence, the edge contrast exceeding the reasonable range is considered high, and the influence on the sample image is high; in this case, the fine-tuning focus knob is adjusted. Under Level 2 influence, the edge contrast exceeding the reasonable range is considered moderate, and the influence on the sample image is moderate; in this case, whether the fine-tuning focus knob should be adjusted requires further judgment.

6. The autofocus method for a high-resolution objective lens according to claim 5, characterized in that, Further judgment is made by acquiring the pixel values ​​of all pixels in the sample display image through sensors, setting a pixel value range threshold according to the normal range, comparing the pixel value of each pixel with the pixel value range threshold, and taking different actions based on the comparison results.

7. The autofocusing method for a high-resolution objective lens according to claim 6, characterized in that, If a pixel value falls within the pixel value range threshold, the pixel is considered an abnormal pixel. If a pixel value does not fall within the pixel value range threshold, the pixel is considered a normal pixel. The number of abnormal pixels is recorded, and the number of abnormal pixels is the noise quantity. A noise quantity threshold is set according to requirements, and the noise quantity is compared with the noise quantity threshold. Different responses are given based on the comparison results.

8. The autofocusing method for a high-resolution objective lens according to claim 7, characterized in that, If the noise count is less than or equal to the noise count threshold, it means the noise count meets the standard. In this case, for secondary effects, the fine-tuning focus knob will not be turned back. If the noise count is greater than the noise count threshold, it means the noise count does not meet the standard. In this case, for secondary effects, the fine-tuning focus knob will be turned back.

9. An autofocus system for a high-resolution objective lens, used to perform the autofocus method for a high-resolution objective lens according to any one of claims 1-8, characterized in that, include: The coarse adjustment module is used to drive the coarse adjustment knob with a displacement motor to bring the objective lens closer to the sample. At the same time, it uses a sensor to obtain the distance between the center point of the objective lens and the center point of the sample. It also sets a distance threshold and compares the distance with the distance threshold. If the distance is less than or equal to the distance threshold, it means that the error between the center point of the sample and the center point of the objective lens is small, and the sample can be regarded as being located at the center of the objective lens. In this case, the sensor then acquires an image of the sample. If a blank area of ​​the slide appears around the sample in the image, the next step can be performed. If no blank area appears on the slide, continue adjusting the coarse focus knob until a blank area appears on the slide. If the distance is greater than the distance threshold, it means that the error between the sample center point and the objective lens center point is large. In this case, continue adjusting the coarse focus knob until the distance is less than or equal to the distance threshold. The fine-tuning module is used to adjust the fine-tuning focus knob by driving the displacement motor. At the same time, it acquires the maximum and minimum brightness values ​​at the edges of the sample image, and obtains the edge contrast by subtracting the minimum brightness value from the maximum brightness value. In addition, it sets the edge contrast threshold according to the parameter information and compares the edge contrast with the edge contrast threshold. If the edge contrast is greater than or equal to the edge contrast threshold, it means that the sample image is clear, and the adjustment stops. If the edge contrast is less than the edge contrast threshold, it means that the image is not clear enough. In this case, the fine-tuning focus knob is adjusted until the edge contrast is greater than or equal to the edge contrast threshold.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is executed by a processor to implement an autofocusing method for a high-resolution objective lens as described in any one of claims 1-8.

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