Method, device and storage medium for collision monitoring in a scanning electron microscope

Abstract

The present application relates to the technical field of scanning electron microscopes, and discloses a method, device, and storage medium for collision monitoring in a scanning electron microscope. The method comprises: collecting an image data stream in a sample chamber of a scanning electron microscope; performing inter-frame difference on two adjacent frames of images in the image data stream to obtain foreground pixels; performing clarity detection on the latter frame of the two adjacent frames of images to obtain a focus area; screening target motion pixels in the foreground pixels that are located in the focus area; and performing collision monitoring in the scanning electron microscope based on the distance between the target motion pixels and the target position. Using the scheme of the present application, accurate moving targets can be determined and the accuracy of collision detection can be improved.

Description

Technical Field

[0001] The present application generally relates to the field of scanning electron microscopy technology. More specifically, the present application relates to a method, an apparatus and a computer-readable storage medium for collision monitoring in a scanning electron microscope. Background Art

[0002] The structure of the scanning electron microscope is very complex, and its parts are numerous and expensive. If the sample stage and the pole shoe collide in the scanning electron microscope due to misoperation, the parts will be damaged, which will cause serious losses. In order to ensure the normal operation of the scanning electron microscope, it is essential to design the production environment to monitor the position of the sample stage. The common method is to use hardware for position monitoring. For example, when the sample stage and the pole shoe are monitored to come into contact, the power is immediately cut off and the movement of the sample stage is locked. This method can only prevent further losses after the collision occurs. In addition, the distance between the sample stage and a specific position can also be monitored by laser and other methods, but laser equipment is expensive. Therefore, how to achieve collision monitoring in a scanning electron microscope while taking into account cost is an important research direction.

[0003] With the continuous development of image processing technology, detection based on computer vision has become the mainstream technical means for dynamic monitoring. The dynamic monitoring method can obtain the position and movement trend of the target of interest in the image through the continuous frame image data captured by the camera. At present, the commonly used dynamic detection algorithms include frame difference method, optical flow method, background difference method, etc. Among them, the frame difference method uses continuous or separated frames to detect moving objects. Although the frame difference method is simple to calculate, the detected target contour is discontinuous. The optical flow method can determine the optical flow vector of the pixel point, but the calculation amount is large and cannot meet the real-time requirements of the scanning electron microscope operation. The background difference method is to make a difference between the current image and the background image, but the background image does not allow moving targets to appear, which cannot meet the preconditions of the electron microscope sample chamber environment. However, there is a mirror effect in certain parts of the sample chamber of the scanning electron microscope, and the moving parts will still move in the mirror, which is reflected as the change of pixels in the adjacent images, but not the moving parts. This phenomenon will greatly affect the moving pixels obtained by the aforementioned dynamic detection algorithm, causing misjudgment of moving objects, thereby further affecting the accuracy of collision monitoring.

[0004] In view of this, there is an urgent need to provide a solution for collision monitoring in a scanning electron microscope in order to determine the accurate moving target and improve the accuracy of collision detection. Summary of the invention

[0005] In order to at least solve one or more of the above-mentioned technical problems, the present application proposes a solution for collision monitoring in a scanning electron microscope in multiple aspects.

[0006] In a first aspect, the present application provides a method for collision monitoring in a scanning electron microscope, comprising: collecting an image data stream in a sample chamber of a scanning electron microscope; performing inter-frame difference on two adjacent frames of images in the image data stream to obtain foreground pixels; performing clarity detection on the latter frame of the two adjacent frames of images to obtain a focus area; screening target motion pixels in the foreground pixels that are located within the focus area; and performing collision monitoring in the scanning electron microscope based on the distance between the target motion pixels and the target position, wherein the clarity detection on the latter frame of the two adjacent frames of images to obtain the focus area comprises: dividing the latter frame of the two adjacent frames of images into a plurality of rectangular areas; performing Laplace filtering on the plurality of rectangular areas to obtain corresponding filtered rectangular areas; calculating the variance of each filtered rectangular area to perform clarity detection on the plurality of rectangular areas; and determining the rectangular area that meets the clarity condition as the focus area.

[0007] In some embodiments, the method further includes: performing a preprocessing operation on the image data stream to obtain a preprocessed image data stream.

[0008] In some other embodiments, performing inter-frame difference on two adjacent frames of images in the image data stream to obtain foreground pixels includes: performing inter-frame difference on two adjacent frames of images in the image data stream to obtain an inter-frame difference result; and setting pixels whose inter-frame difference results are greater than a first threshold as target values ​​to obtain the foreground pixels.

[0009] In some other embodiments, dividing the latter frame image of two adjacent frames into multiple rectangular areas includes: setting a window size and a window step; and moving the window based on the window size and the window step to divide the latter frame image of two adjacent frames into the multiple rectangular areas.

[0010] In some further embodiments, determining a rectangular area satisfying a definition condition as the focus area comprises: determining a rectangular area corresponding to a filtered rectangular area having a variance greater than or equal to a second threshold as the focus area.

[0011] In some other embodiments, screening the target motion pixels located in the focus area from among the foreground pixels comprises: calculating the intersection between the foreground pixels and the focus area to determine a foreground point in the focus area; and obtaining a foreground point with the smallest ordinate in the focus area to screen the target motion pixels located in the focus area from among the foreground pixels.

[0012] In some further embodiments, collision monitoring in the scanning electron microscope based on the distance between the target motion pixel and the target position includes: in response to the distance between the target motion pixel and the target position being greater than a third threshold, determining that there is a collision risk in the scanning electron microscope.

[0013] In a second aspect, the present application provides a device for collision monitoring in a scanning electron microscope, comprising: a processor; and a memory, in which program instructions for collision monitoring in a scanning electron microscope are stored, and when the program instructions are executed by the processor, the device implements one or more embodiments of the aforementioned first aspect.

[0014] In a third aspect, the present application provides a computer-readable storage medium having stored thereon computer-readable instructions for collision monitoring in a scanning electron microscope, wherein when the computer-readable instructions are executed by one or more processors, one or more embodiments of the aforementioned first aspect are implemented.

[0015] Through the scheme for collision monitoring in a scanning electron microscope provided above, the embodiment of the present application first obtains the foreground pixels of the moving target by performing inter-frame difference on two adjacent frames of images in the image data stream in the sample chamber of the scanning electron microscope. Then, the clarity detection is performed on the latter frame of the image to obtain the focus area, so as to filter out the motion of the moving target projection reflected by the surface of the component, obtain accurate target motion pixels, and then realize accurate collision monitoring through the distance between the target motion pixels and the target position. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become easy to understand. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0017] Figure 1 is an exemplary flowchart showing a method for collision monitoring in a scanning electron microscope according to an embodiment of the present application;

[0018] Figure 2 is an exemplary flow chart showing an overall process for collision monitoring in a scanning electron microscope according to an embodiment of the present application;

[0019] Figure 3 is an exemplary schematic diagram showing collision monitoring in a scanning electron microscope according to an embodiment of the present application;

[0020] Figure 4 is an exemplary structural block diagram showing a device for collision monitoring in a scanning electron microscope according to an embodiment of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0022] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present application indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0023] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this application specification and claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms. It should also be further understood that the term "and / or" used in this application specification and claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0024] As used in this specification and claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0025] The specific implementation of the present application is described in detail below with reference to the accompanying drawings.

[0026] Figure 1 FIG. 1 is an exemplary flowchart of a method 100 for collision monitoring in a scanning electron microscope according to an embodiment of the present application. Figure 1As shown in , at step S101, an image data stream in a sample chamber of a scanning electron microscope is collected. In some embodiments, the image data stream (i.e., continuous frame image data) of the environment in the sample chamber of the scanning electron microscope can be captured by, for example, a grayscale camera. In some embodiments, based on the collected image data stream, the image data stream can first be preprocessed to obtain a preprocessed image data stream. The aforementioned preprocessing operation may include but is not limited to operations such as image denoising, filtering, or enhancement. The image data stream after the preprocessing operation can obtain a high-quality image to facilitate subsequent accurate calculations.

[0027] Next, at step S102, inter-frame difference is performed on two adjacent frames of images in the image data stream to obtain foreground pixels. In some embodiments, inter-frame difference can be performed on two adjacent frames of images in the image data stream to obtain inter-frame difference results, and the foreground pixels are obtained by setting the pixels whose inter-frame difference results are greater than the first threshold as the target value. It can be understood that the inter-frame difference method can monitor inter-frame moving objects, and the contour of the moving target can be captured by performing inter-frame difference on two adjacent frames of images in the image data stream. Among them, the aforementioned inter-frame difference is the absolute value of the pixel difference between the corresponding positions of the two adjacent frames of images, that is, the aforementioned inter-frame difference result. Next, it is determined whether the inter-frame difference result is greater than the first threshold. If the inter-frame difference result is greater than the first threshold, it means that the pixel position in the image moves and there is a moving target; otherwise, the pixel position does not move and is a stationary target. In some implementation scenarios, by setting the pixels whose inter-frame difference results are greater than the first threshold as the target value, the foreground pixels of the moving target can be obtained. That is, by setting the pixel value at the position where the moving target exists to the target value (for example, 1), and setting the remaining pixel values ​​to, for example, 0, the foreground pixel of the moving target can be obtained.

[0028] In an implementation scenario, the foreground pixel can be obtained by the following formula:

[0029] (1)

[0030] in, represents the foreground pixel of the moving target at time t, and represents the adjacent t-th frame image and t-1-th frame image, represents the inter-frame difference result, and T represents the first threshold value, which can be set according to the collision monitoring requirements.

[0031] Further, at step S103, the clarity detection is performed on the latter frame of the two adjacent frames to obtain the focus area. It should be understood that the moving target obtained by the aforementioned inter-frame difference method is often not accurate enough. This is because in the sample chamber of the scanning electron microscope, the surfaces of more parts will reflect the projection of the moving target, and these parts themselves are stationary. However, the motion of the projection will also be captured by the inter-frame difference method. In actual production, the grayscale camera in the sample chamber of the scanning electron microscope has been pre-focused on the sample stage and the pole shoe. The image captured by the camera shows a clearer image at the sample stage and the pole shoe than other non-focused areas, and the moving part of the projection often occurs in the unfocused background part. Therefore, the embodiment of the present application can obtain the focus area (i.e., the position of the sample stage and the pole shoe) in the image by combining the clarity detection, and by distinguishing the focus area, the motion of the projection can be screened out, thereby obtaining a more accurate moving target.

[0032] In some embodiments, the latter frame of the two adjacent frames can be divided into multiple rectangular areas, the clarity detection can be performed on the multiple rectangular areas, and the rectangular areas that meet the clarity conditions can be determined as the focus areas. Specifically, in some embodiments, the latter frame of the two adjacent frames can be divided into multiple rectangular areas by setting the window size and the window step, and the window can be moved based on the window size and the window step. As an example, by setting the window size and window step , you can get the rectangular box collection , so that the latter frame of the two frames is Divide into multiple rectangular areas.

[0033] In some embodiments, when performing clarity detection on multiple rectangular areas, Laplace filtering can be performed on the multiple rectangular areas to obtain corresponding filtered rectangular areas, and then the variance of each filtered rectangular area is calculated to perform clarity detection on the multiple rectangular areas. That is, clarity detection is performed by calculating the variance of the image in all filtered rectangular areas, and the larger the variance, the higher the image clarity. In some implementation scenarios, the second-order derivative of each rectangular area can be calculated by the Laplace operator to perform Laplace filtering on the multiple rectangular areas.

[0034] In some embodiments, after obtaining the variance of the images in all rectangular regions, the rectangular region corresponding to the filtered rectangular region having a variance greater than or equal to the second threshold is determined as the focus region. In an exemplary scenario, the focus region can be determined by the following formula: :

[0035] (2)

[0036] in, , Represents the coordinate position of the i-th rectangular area, Indicates the position coordinates of the upper left corner of the rectangular area. represents the i-th rectangular area in the t-th frame image, K represents the second threshold, represents the window size. Further, represents Laplace filtering, represents the calculation of variance, Represents the empty set.

[0037] Based on the foreground pixels and the focus area obtained above, at step S104, the target motion pixels in the foreground pixels that are located in the focus area are screened. In some embodiments, the foreground point in the focus area can be determined by calculating the intersection between the foreground pixels and the focus area, and then the foreground point with the smallest ordinate in the focus area is obtained to screen the target motion pixels in the foreground pixels that are located in the focus area. In an implementation scenario, it is assumed that the foreground point in the focus area is denoted as ,but ,in represents the foreground pixel, Indicates the focus area, Furthermore, the target motion pixel located in the focus area can be expressed by the following formula:

[0038] (3)

[0039] in, It represents the target motion pixel located in the focus area, which corresponds to the foreground point with the minimum ordinate in the focus area.

[0040] Further, at step S105, collision monitoring in the scanning electron microscope is performed based on the distance between the target motion pixel and the target position. In some embodiments, in response to the distance between the target motion pixel and the target position being greater than a third threshold, it is determined that there is a collision risk in the scanning electron microscope. In an implementation scenario, the target position is the pixel position of the pole shoe in the image, and when the grayscale camera in the scanning electron microscope sample compartment is fixed, the pixel position of the pole shoe in the grayscale image is fixed. When performing collision monitoring, if it is detected that the distance between the target motion pixel and the position of the pole shoe is greater than the third threshold, it is determined that there is a collision risk to initiate a collision warning. Otherwise, there is no collision risk.

[0041] In an exemplary scenario, assume that the vertical coordinate of the target position is marked as , the distance between the target motion pixel and the target position is recorded as ,and In addition, the third threshold is recorded as G, and the collision monitoring in the scanning electron microscope can be performed by the following formula:

[0042] (4)

[0043] In combination with the above description, it can be seen that the embodiment of the present application first calculates the inter-frame difference between two adjacent frames of images in the image data stream in the sample chamber of the scanning electron microscope to capture the foreground pixels of all moving targets. Then, combined with the clarity detection of the next frame of image, the motion of the projection of the moving target reflected on the surface of the part is screened out to obtain accurate target motion pixels. Furthermore, by calculating the distance between the target motion pixel and the target position, accurate collision monitoring can be achieved.

[0044] Figure 2 FIG. 1 is an exemplary flow chart showing the overall process of collision monitoring in a scanning electron microscope according to an embodiment of the present application. Figure 2 As shown in , at step S201, an image data stream in a sample chamber of a scanning electron microscope is collected. In some embodiments, a grayscale camera can be used for collection. Based on the collected image data stream, at step S202, a preprocessing operation is performed on the image data stream. In some embodiments, the preprocessing operation can be, for example, image denoising, filtering, or enhancement operations.

[0045] Next, at step S203, inter-frame difference is first performed on two adjacent frames of the image data stream to obtain an inter-frame difference result. , and at step S204, the pixels whose inter-frame difference results are greater than the first threshold T are determined as foreground pixels of the moving target , please refer to the above formula (1) for details.

[0046] On the other hand, at step S205, the latter frame of the two adjacent frames of images is first divided into a plurality of rectangular regions. In some embodiments, the window size and the window step can be set, and the window can be moved based on the window size and the window step to divide the latter frame of the two adjacent frames of images into a plurality of rectangular regions. Then in step S206, Laplace filtering is performed on each rectangular area, and the variance is calculated. , and at step S207, the variance of the filtered rectangular area is A rectangular area greater than or equal to the second threshold K is determined as a focus area , please refer to the above formula (2) for details.

[0047] Getting foreground pixels and focus area Then, at step S208, the foreground pixels are calculated and focus area The foreground point is obtained by the intersection of (See the above formula (3)) to filter out target motion pixels in the foreground pixels that are within the focus area.

[0048] Further, at step S209, the target motion pixel is determined and target location The distance between Is it greater than the third threshold G. If the distance between the target motion pixel and the position of the pole shoe is greater than the third threshold, at step S210, it is determined that there is a collision risk to start a collision warning. Otherwise, at step S211, it is determined that there is no collision risk.

[0049] Figure 3 is an exemplary schematic diagram showing collision monitoring in a scanning electron microscope according to an embodiment of the present application. It should be understood that Figure 3 is the above Figure 1 A specific embodiment of Figure 1 The description also applies to Figure 3 .

[0050] like Figure 3 exemplarily shows an image data stream from time t to time t+n in a sample chamber of a scanning electron microscope, and two adjacent frames of images, such as image 301 at time t and image 302 at time t+1, are determined. First, inter-frame difference is performed on image 301 at time t and image 302 at time t+1 to obtain foreground pixel 303. Specifically, inter-frame difference is performed on image 301 at time t and image 302 at time t+1 to obtain an inter-frame difference result, and pixels greater than a first threshold in the inter-frame difference result are set to 1, and the remaining pixels are set to 0 to obtain foreground pixel 303.

[0051] The figure further shows that by setting the window size and the window step, the window is moved based on the window size and the window step (for example, as shown in the rectangular frame A), so as to divide the image 302 at time t+1 into multiple rectangular areas. Then, the clarity detection is performed on the multiple rectangular areas, including Laplace filtering and calculating the variance 304, and the rectangular area corresponding to the variance of the filtered rectangular area being greater than or equal to the second threshold is determined as the focus area 305.

[0052] Furthermore, the target motion pixels in the foreground pixels 303 that are located in the focus area 305 are screened. Specifically, the intersection between the foreground pixels and the focus area is calculated to determine the foreground points in the focus area, and the target motion pixels are determined by screening the foreground points with the smallest ordinates in the focus area. Finally, collision monitoring in the scanning electron microscope is performed by calculating and based on the distance between the target motion pixels and the target position. For example, there is a collision risk at the distance L1 in the figure, but there is no collision risk at the distance L2. For more details about collision monitoring, please refer to the above Figure 1-Figure 2 The described contents will not be repeated in this application.

[0053] Based on the collision monitoring solution of the embodiment of the present application, by combining the clarity detection on the inter-frame difference, it is possible to capture the comprehensive moving target pixels while suppressing the influence of the background projection movement on the inter-frame difference, thereby obtaining accurate target moving pixels, improving the accuracy of collision monitoring, and being more robust. In addition, the embodiment of the present application only combines the clarity detection on the inter-frame difference, which reduces the computational complexity and improves the efficiency of collision monitoring.

[0054] Figure 4 FIG. 4 is an exemplary structural block diagram showing a device 400 for collision monitoring in a scanning electron microscope according to an embodiment of the present application. Figure 4 As shown in , the device 400 of the present application may include a processor 401 and a memory 402, wherein the processor 401 and the memory 402 communicate with each other via a bus. The memory 402 stores program instructions for collision monitoring in a scanning electron microscope. When the program instructions are executed by the processor 401, the method steps described in the above text in combination with the accompanying drawings are implemented: collecting an image data stream in a sample bin of a scanning electron microscope; performing inter-frame difference on two adjacent frames of images in the image data stream to obtain foreground pixels; performing clarity detection on the latter frame of the two adjacent frames of images to obtain a focus area; screening target motion pixels in the foreground pixels that are located in the focus area; and performing collision monitoring in the scanning electron microscope based on the distance between the target motion pixels and the target position.

[0055] According to the above description in combination with the accompanying drawings, those skilled in the art can also understand that the embodiments of the present application can also be implemented by a software program. Therefore, the present application also provides a computer-readable storage medium. The computer-readable storage medium stores computer-readable instructions for collision monitoring in a scanning electron microscope. When the computer-readable instructions are executed by one or more processors, the present application in combination with the accompanying drawings can be implemented. Figure 1 A method for collision monitoring in a scanning electron microscope is described.

[0056] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0057] It should be noted that although the operations of the method of the present application are described in a specific order in the accompanying drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. On the contrary, the steps depicted in the flow chart can be performed in a different order. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0058] It should be understood that when the terms "first", "second", "third" and "fourth" are used in the claims, the specification and the drawings of the present application, they are only used to distinguish different objects, rather than to describe a specific order. The terms "include" and "comprise" used in the specification and claims of the present application indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their collections.

[0059] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this application specification and claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms. It should also be further understood that the term "and / or" used in this application specification and claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0060] Although the implementation methods of the present application are as above, the contents described are only examples adopted to facilitate the understanding of the present application, and are not intended to limit the scope and application scenarios of the present application. Any technician in the technical field described in the present application can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present application, but the scope of patent protection of the present application shall still be subject to the scope defined in the attached claims.

Claims

1. A method for collision monitoring in a scanning electron microscope, characterized in that include: Collecting image data stream in a sample chamber of a scanning electron microscope; Performing inter-frame difference on two adjacent frames of images in the image data stream to obtain foreground pixels; Performing clarity detection on the latter frame of two adjacent frames of images to obtain a focus area; Screening target moving pixels located in the focus area from the foreground pixels; as well as, performing collision monitoring in the scanning electron microscope based on the distance between the target motion pixel and the target position, The clarity detection of the latter frame of two adjacent frames of images to obtain the focus area includes: Divide the latter frame image of two adjacent frame images into a plurality of rectangular regions; Performing Laplace filtering on the multiple rectangular areas to obtain corresponding filtered rectangular areas; Calculating the variance of each filtered rectangular area to perform clarity detection on the plurality of rectangular areas; A rectangular area that meets the definition condition is determined as the focus area.

2. The method according to claim 1, characterized in that Also includes: A preprocessing operation is performed on the image data stream to obtain a preprocessed image data stream.

3. The method according to claim 1 or 2, characterized in that: The step of performing inter-frame difference on two adjacent frames of images in the image data stream to obtain foreground pixels comprises: performing inter-frame difference on two adjacent frames of images in the image data stream to obtain an inter-frame difference result; and, The pixels whose inter-frame difference results are greater than a first threshold are set as target values ​​to obtain the foreground pixels.

4. The method according to claim 1, characterized in that Wherein dividing the latter frame image of two adjacent frames of images into a plurality of rectangular areas comprises: Setting window size and window step; and, The window is moved based on the window size and the window step to divide the latter frame image of two adjacent frame images into the multiple rectangular areas.

5. The method according to claim 1, characterized in that Wherein determining a rectangular area satisfying the definition condition as the focus area comprises: A rectangular area corresponding to a rectangular area whose variance after filtering is greater than or equal to the second threshold is determined as the focus area.

6. The method according to claim 1, characterized in that The screening of the target moving pixels in the foreground pixels and located in the focus area comprises: calculating the intersection between the foreground pixels and the focus area to determine the foreground points within the focus area; and, A foreground point with the smallest ordinate in the focus area is obtained to screen the target moving pixels located in the focus area from the foreground pixels.

7. The method according to claim 1, characterized in that The collision monitoring in the scanning electron microscope based on the distance between the target motion pixel and the target position includes: In response to the distance between the target motion pixel and the target position being greater than a third threshold, it is determined that there is a collision risk in the scanning electron microscope.

8. A device for collision monitoring in a scanning electron microscope, characterized in that include: processor; as well as, A memory, wherein program instructions for collision monitoring in a scanning electron microscope are stored, and when the program instructions are executed by the processor, the device implements the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: Computer-readable instructions for collision monitoring in a scanning electron microscope are stored thereon, and when the computer-readable instructions are executed by one or more processors, the method according to any one of claims 1 to 7 is implemented.

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