Method, device, computer equipment, readable storage medium and computer program product for positioning a marking center

Abstract

The present application relates to a method, device, computer equipment, readable storage medium and computer program product for positioning the center of a mark. The method comprises: sequentially connecting the first contour points in the mark image to form a first contour; rotating the first contour around the initial mark center by a preset angle to obtain a second contour; repeating the following operations on the second contour: determining the target straight line where the first contour point whose distance from the second contour point meets the preset distance condition is located, using the direction vector from the target point in the second contour to the corresponding target straight line to generate a translation vector, and translating the second contour according to the translation vector to obtain a new second contour until the new second contour meets the preset stop condition; locating the target mark center of the mark image according to the initial mark center and the translation vector. The method can locate the target mark center by using a simple graphic transformation method based on the inherent central symmetry of the mark, and is widely applicable and robust.

Description

Technical Field

[0001] The present application relates to the technical field of image analysis, and in particular to a method, device, computer equipment, computer-readable storage medium and computer program product for locating a marking center. Background Art

[0002] In the wafer production process, in order to accurately fit two wafers, a wafer alignment system is usually used. Since the wafer is engraved with a centrally symmetrical mark, the wafer alignment system can use the center point of the mark as an alignment reference to achieve wafer alignment.

[0003] In conventional technology, the grayscale information of the marked image can be projected onto a straight line by grayscale projection. Then, the center coordinates of the marked image can be calculated based on the central symmetry of the marked image. Alternatively, the center position of the marked image can be calculated by using the median line of the symmetric line segment formed by the contour line segment of the marked image and the contour line segment rotated by a preset angle.

[0004] However, different batches of wafers have different types of marks. The grayscale projection method is not applicable to pure contour mark images. The line segmentation method is not applicable to mark images with a large arc angle and a small straight line angle. Therefore, a widely applicable mark center positioning method is urgently needed. Summary of the invention

[0005] Based on this, it is necessary to provide a more robust marking center positioning method, device, computer equipment, computer-readable storage medium and computer program product to address the above technical problems.

[0006] In a first aspect, the present application provides a method for locating a marking center, comprising:

[0007] Acquire a marked image, and sequentially connect first contour points in the marked image to form a first contour;

[0008] Determine an initial marking center of the first contour according to the first contour points, and rotate the first contour around the initial marking center by a preset angle to obtain a second contour;

[0009] Repeat the following steps for the second profile:

[0010] Querying from the first contour to obtain a first contour point whose distance from the second contour point in the second contour satisfies a preset distance condition, determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located,

[0011] Determine the target point in the second contour according to the positional relationship between the second contour point and the target straight line,

[0012] A translation vector is generated by using the direction vector from the target point to the corresponding target straight line, and the second contour is translated according to the translation vector to obtain a new second contour,

[0013] until the new second profile meets a preset stop condition;

[0014] The target marking center of the marking image is located according to the initial marking center and the translation vector.

[0015] In one embodiment, querying from the first contour to obtain a first contour point whose distance to a second contour point in the second contour satisfies a preset distance condition, and determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located includes:

[0016] Performing downsampling processing on the second contour to obtain second contour points in the second contour;

[0017] Acquire a tree data structure corresponding to the first contour;

[0018] Using the tree data structure to query and obtain a first contour point whose distance to the second contour point meets a preset distance condition;

[0019] A target straight line is determined where a first contour point whose distance satisfies a preset distance condition is located.

[0020] In one embodiment, the tree data structure is generated in the following manner:

[0021] Obtaining a first standard deviation corresponding to the horizontal axis coordinate of each of the first contour points, and a second standard deviation corresponding to the vertical axis coordinate of each of the first contour points;

[0022] Determining a target segmentation axis from a horizontal axis and a vertical axis according to a comparison result of the first standard deviation and the second standard deviation;

[0023] Each of the first contour points is divided according to the target segmentation axis and the coordinates of each of the first contour points on the target segmentation axis to obtain the tree data structure.

[0024] In one embodiment, the preset stop condition includes at least one of the following conditions:

[0025] The target point ratio of the new second contour is not greater than the target point ratio of the second contour before translation;

[0026] The target point ratio of the new second contour is greater than a preset ratio threshold;

[0027] Repeat the operation a number of times up to the iteration threshold.

[0028] In one embodiment, determining the target point in the second contour according to the positional relationship between the second contour point and the target straight line includes:

[0029] Acquire a first perpendicular foot from the second contour point to the target straight line;

[0030] When the first perpendicular foot is located between the first contour points whose distances satisfy a preset distance condition, the second contour point is used as the target point.

[0031] In one embodiment, determining the target point in the second contour according to the positional relationship between the second contour point and the target straight line includes:

[0032] Acquire a second perpendicular foot from a second contour point in the new second contour to the corresponding target straight line;

[0033] When the second perpendicular foot is located between the corresponding first contour points whose distances meet a preset distance condition, and the distance from the second contour point to the second perpendicular foot is not greater than a preset distance threshold, the second contour point is used as a target point in the new second contour.

[0034] In a second aspect, the present application also provides a positioning device for a marking center, comprising:

[0035] A contour extraction module, used for acquiring a marked image, and sequentially connecting first contour points in the marked image to form a first contour;

[0036] A contour rotation module, used to determine an initial marking center of the first contour according to the first contour points, and to rotate the first contour around the initial marking center by a preset angle to obtain a second contour;

[0037] an iterative adjustment module, configured to repeatedly perform the following operations on the second contour: querying from the first contour to obtain a first contour point whose distance from a second contour point in the second contour satisfies a preset distance condition, determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located, determining a target point in the second contour according to a positional relationship between the second contour point and the target straight line, generating a translation vector using a direction vector from the target point to the corresponding target straight line, and translating the second contour according to the translation vector to obtain a new second contour, until the new second contour satisfies a preset stop condition;

[0038] A center positioning module is used to locate the target marking center of the marking image according to the initial marking center and the translation vector.

[0039] In a third aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method for locating the marking center described in any one of the embodiments of the first aspect is implemented.

[0040] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for locating the marking center described in any one of the embodiments of the first aspect above is implemented.

[0041] In a fifth aspect, the present application further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the method for locating the center of a marker as described in any one of the embodiments of the first aspect above is implemented.

[0042] The above-mentioned method, device, computer equipment, computer-readable storage medium and computer program product for positioning the mark center obtain a mark image, connect the first contour points in the mark image in sequence to form a first contour; determine the initial mark center of the first contour according to the first contour points, and rotate the first contour around the initial mark center by a preset angle to obtain a second contour; repeatedly perform the translation operation on the second contour until the new second contour obtained after the translation meets the preset stop condition, and locate the target mark center of the mark image according to the translation vector used in each translation process of the initial mark center and the second contour. Based on the inherent central symmetry of the mark Mark that coincides with itself after rotating around the target mark center by a preset angle, the target mark center can be located by simple graphic transformation means such as rotation and translation. There is no requirement for the filling color of the mark Mark, the line composition of the mark Mark, or the style of the mark Mark. The method is suitable for various types of mark center extraction scenarios, and the robustness of the mark center positioning method is improved. In addition, when the marking center positioning method provided in the above embodiment is adopted, since only the direction vector from the target point in the second contour to the corresponding target straight line is used to calculate the translation vector during each translation, it is also possible to avoid the influence of redundant contour points and erroneous contour points in the marking image due to dirt, pollution, noise, etc. on the positioning of the target marking center, thereby improving the anti-interference ability of the marking center positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A schematic diagram of a flow chart of a method for locating a marking center in one embodiment;

[0045] Figure 2 A schematic flow chart of a target straight line determination step in one embodiment;

[0046] Figure 3 A schematic diagram of a process of generating a tree data structure in one embodiment;

[0047] Figure 4 A schematic diagram of a flow chart of a method for locating a marking center in another embodiment;

[0048] Figure 5 A schematic diagram of a tree data structure in one embodiment;

[0049] Figure 6 A schematic diagram of a target point determination step in one embodiment;

[0050] Figure 7 is a schematic diagram of a first profile in one embodiment;

[0051] Figure 8 is a schematic diagram of a second profile in one embodiment;

[0052] Fig. 9 is a structural block diagram of a positioning device 900 for marking a center in one embodiment;

[0053] Fig.10 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0055] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0056] In an exemplary embodiment, Figure 1 As shown, a method for locating a marking center is provided. This embodiment uses the method applied to a terminal as an example. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. Among them, the terminal can be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, Internet of Things devices and portable wearable devices. The Internet of Things devices can be smart TVs, smart car devices, projection devices, etc. Portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The head-mounted device can be a virtual reality (VR) device, an augmented reality (AR) device, smart glasses, etc. The server can be an independent physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0057] In this embodiment, the method includes the following steps:

[0058] Step S102: acquiring a marked image, and sequentially connecting first contour points in the marked image to form a first contour.

[0059] The mark image can be used to represent an image acquired from a mark Mark having central symmetry on a wafer.

[0060] The first contour point can be used to characterize a boundary point in the marker image.

[0061] Optionally, in some embodiments, the terminal can establish data communication with the image acquisition device, and read the wafer image acquired by the image acquisition device on the production line through the data communication. Based on image segmentation, image recognition or template matching, the image area where the mark Mark engraved on the wafer is located is identified from the complete wafer image. For the identified image area, the marked image is extracted from the wafer image. Alternatively, in other embodiments, the terminal can also receive the marked image input by the user through the front-end interactive component. Alternatively, in other embodiments, the terminal can also download the marked image through the Internet.

[0062] Optionally, in some embodiments, the terminal may store an edge detection algorithm, such as a Canny algorithm, a Sobel algorithm, a Prewitt algorithm, etc. The edge detection algorithm is used to perform edge detection on the marked image to obtain first contour points in the marked image. According to the distance between the first contour points, each first contour point is sequentially connected to form a first contour.

[0063] Step S104, determining an initial marking center of the first contour according to the first contour points, and rotating the first contour around the initial marking center by a preset angle to obtain a second contour.

[0064] The initial mark center can be used to represent the roughly obtained rotation center of the mark Mark in this embodiment, and there is still a certain error compared with the actual rotation center of the mark Mark.

[0065] The preset angle can be determined based on the central symmetry of the mark Mark: when a figure with central symmetry rotates around its rotation center by a preset angle, it can coincide with the figure itself. For example, when the mark Mark is a triangle, its preset angle can be 120°. When the mark Mark is a quadrilateral, its preset angle can be 180°.

[0066] Optionally, in some embodiments, the terminal may use each first contour point to form a point set, and obtain the initial marking center of the first contour by calculating the centroid, geometric center, or center of the minimum circumscribed circle of the point set. The first contour is rotated around the initial marking center by a preset angle to obtain the rotated first contour. The rotated first contour is used as the second contour. The following steps S106 to S112 are repeatedly performed on the second contour until the new second contour meets the preset stop condition.

[0067] Step S106, querying from the first contour to obtain a first contour point whose distance to the second contour point in the second contour satisfies a preset distance condition, and determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located.

[0068] The preset distance condition may be used to filter out the two points that are closest to the second contour point.

[0069] Exemplarily, the terminal may store a neighbor search algorithm, such as a ball tree algorithm (BallTree), a K-dimensional tree algorithm (KDTree), a brute force search algorithm (Brute Force), etc. According to the coordinates of the second contour point in the second contour, the neighbor search algorithm may be used to query the first contour to obtain a first contour point whose distance from the second contour point meets a preset distance condition. Connect the two first contour points whose distance from the second contour point meets the preset distance condition to obtain the target straight line where the two first contour points are located.

[0070] Step S108, determining the target point in the second contour according to the positional relationship between the second contour point and the target straight line.

[0071] Optionally, in some embodiments, the terminal may detect the distance between the second contour point and the target straight line corresponding to the second contour point. The second contour point whose distance in the second contour is less than a preset distance threshold is used as the target point. Alternatively, in other embodiments, the terminal may also determine the foot of the perpendicular from the second contour point to the target straight line. When it is determined that the foot of the perpendicular is between two first contour points that meet the preset distance condition, the corresponding second contour point is used as the target point.

[0072] Step S110: Generate a translation vector using the direction vector from the target point to the corresponding target straight line, and translate the second contour according to the translation vector to obtain a new second contour.

[0073] The translation vector may be used to indicate the direction and distance that the second contour needs to move.

[0074] Exemplarily, the terminal may determine the direction vector from the target point to the corresponding target straight line according to the target point and the foot of the perpendicular from the target point to the corresponding target straight line. A vector set is formed using the direction vectors corresponding to each target point. The coordinate average of the vector set is calculated to obtain the current translation vector. The current second contour is translated according to the current translation vector to obtain a new second contour.

[0075] Step S112, determining whether the new second contour satisfies a preset stop condition.

[0076] Exemplarily, the terminal may store a preset stop condition. The terminal may determine whether the new second contour satisfies the preset stop condition based on the number of times the above steps are repeated for the second contour, the proportion of the number of target points of the new second contour, or the difference between the new second contour and the second contour before translation. When the new second contour does not meet the preset stop condition, the operations of the above steps S106 to S110 are continued. When the new second contour meets the preset stop condition, the following step S114 is executed.

[0077] Step S114, locating the target marking center of the marking image according to the initial marking center and the translation vector.

[0078] The target mark center may represent the rotation center of the mark Mark finally output in this embodiment.

[0079] Exemplarily, the terminal may translate the initial mark center according to the translation vector of each translation of the second contour to obtain the translated initial mark center, and use the translated initial mark center as the target mark center of the mark Mark.

[0080] In the above-mentioned method for positioning the mark center, a mark image is obtained, and the first contour points in the mark image are sequentially connected to form a first contour; the initial mark center of the first contour is determined according to the first contour points, and the first contour is rotated around the initial mark center by a preset angle to obtain a second contour; the translation operation is repeatedly performed on the second contour until a new second contour obtained after the translation meets a preset stop condition, and the target mark center of the mark image is located according to the translation vector used in each translation process of the initial mark center and the second contour. Based on the inherent central symmetry of the mark Mark that coincides with itself after rotating around the target mark center by a preset angle, the target mark center can be located by simple graphic transformation means such as rotation and translation. There is no requirement for the filling color of the mark Mark, the line composition of the mark Mark, or the style of the mark Mark. The method is suitable for various types of mark center extraction scenarios, thereby improving the robustness of the mark center positioning method. In addition, when using the marking center positioning method provided in this embodiment, since only the direction vector from the target point in the second contour to the corresponding target straight line is used to calculate the translation vector during each translation, it is also possible to avoid the influence of redundant contour points and erroneous contour points in the marking image due to dirt, pollution, noise, etc. on the positioning of the target marking center, thereby improving the anti-interference ability of the marking center positioning method.

[0081] In an exemplary embodiment, Figure 2 As shown, the above step S106 may also include the following steps S202 to S208. Among them:

[0082] Step S202: down-sample the second contour to obtain second contour points in the second contour.

[0083] Step S204: Obtain a tree data structure corresponding to the first outline.

[0084] Step S206: using the tree data structure to query and obtain a first contour point whose distance to the second contour point satisfies a preset distance condition.

[0085] Step S208, determining a target straight line where the first contour point whose distance satisfies a preset distance condition is located.

[0086] The tree data structure may be used to store the positional relationship between the first contour points in the first contour.

[0087] Exemplarily, the terminal may perform downsampling processing on the second contour, for example, selecting one point every n (such as 3, 5, 7, etc.) points as the second contour point. Obtain the tree data structure corresponding to the first contour. Perform the following operations for each second contour point: Start querying from the root node of the tree data structure. If the coordinate of the second contour point on the segmentation dimension of the tree data structure is less than the root node, continue to determine the coordinates of the child node on the left side of the root node and the second contour point on the segmentation dimension, otherwise determine the coordinates of the child node on the right side of the root node and the second contour point on the segmentation dimension. Until the leaf node at the end of the tree data structure is queried. Calculate the distance between the leaf node and the second contour point. Take the second contour point as the center of the circle and the distance between the leaf node and the second contour point as the radius to determine the circular area. If the remaining child nodes of the parent node of the leaf node fall into the circular area, a backtracking search is required: along the search path from the root node to the leaf node, perform a reverse search with reference to the above search steps. Thus, the two first contour points closest to the second contour point in the first contour are queried and used as the first contour points that meet the preset distance threshold. According to the coordinates of the first contour point that meets the preset distance threshold, a target straight line at which the first contour point that meets the preset distance condition is located is determined.

[0088] In this embodiment, by downsampling the second contour to obtain the second contour point, the amount of data calculation can be reduced and the data processing efficiency can be improved. By using a tree data structure to query and obtain the two first contour points closest to the second contour point in the first contour, the query efficiency of the first contour point can be improved.

[0089] In an exemplary embodiment, Figure 3 As shown, a method for generating a tree data structure is provided, including the following steps S302 to S306. Among them:

[0090] Step S302 , obtaining a first standard deviation corresponding to the horizontal axis coordinate of each first contour point, and a second standard deviation corresponding to the vertical axis coordinate of each first contour point.

[0091] For example, the terminal may calculate the standard deviation of the horizontal axis coordinates using the horizontal axis coordinates of each first contour point, and use the standard deviation of the horizontal axis coordinates as the first standard deviation corresponding to each first contour point. Calculate the standard deviation of the vertical axis coordinates using the vertical axis coordinates of each first contour point, and use the standard deviation of the vertical axis coordinates as the second standard deviation corresponding to each first contour point.

[0092] Step S304: determining a target segmentation axis from the horizontal axis and the vertical axis according to the comparison result of the first standard deviation and the second standard deviation.

[0093] Step S306 , dividing each first contour point according to the target segmentation axis and the coordinates of each first contour point on the target segmentation axis to obtain a tree data structure.

[0094] Optionally, in some embodiments, when the first standard deviation is greater than the second standard deviation, the horizontal axis corresponding to the first standard deviation can be used as the target segmentation axis. The median of the horizontal axis coordinates is calculated using the horizontal axis coordinates of each first contour point on the target segmentation axis. The first contour point at the median or the closest to the median is used as the root node in the tree data structure. With the first contour point at the root node as the center, the first contour point with a horizontal axis coordinate smaller than the root node is divided into the child node on the left side of the root node, and the first contour point with a horizontal axis coordinate larger than the root node is divided into the child node on the right side of the root node, thereby forming a tree data structure corresponding to the first contour.

[0095] Optionally, in some other embodiments, when the second standard deviation is greater than the first standard deviation, the vertical axis corresponding to the second standard deviation can be used as the target segmentation axis. The median of the vertical axis coordinates is calculated using the vertical axis coordinates of each first contour point on the target segmentation axis. The first contour point at the median or the closest to the median is used as the root node in the tree data structure. With the first contour point at the root node as the center, the first contour point with a vertical axis coordinate less than the root node is divided into the child node on the left side of the root node, and the first contour point with a vertical axis coordinate greater than the root node is divided into the child node on the right side of the root node, thereby forming a tree data structure corresponding to the first contour.

[0096] In this embodiment, the target segmentation axis is determined based on the larger one of the standard deviation of the horizontal axis coordinate and the standard deviation of the vertical axis coordinate of each first contour point, and each first contour point is divided to form a tree data structure. The coordinate values ​​with large differences between each first contour point can be used for segmentation, thereby improving the division efficiency of the tree data structure.

[0097] In an exemplary embodiment, the above step S108 can be implemented in the following manner:

[0098] Get the first perpendicular foot from the second contour point to the target straight line;

[0099] When the first perpendicular foot is located between the first contour points whose distances satisfy the preset distance condition, the second contour point is taken as the target point.

[0100] For example, the terminal can calculate the first perpendicular foot from the second contour point to the target straight line using the coordinates of the second contour point and the function expression of the target straight line. When the first perpendicular foot is located between the first contour points whose distances meet the preset conditions, the second contour point can be regarded as a target point under the inner point category.

[0101] Optionally, in some other implementations, when the first perpendicular foot is located outside the first contour point within a preset condition, the second contour point may be regarded as a boundary point under the external point category for filtering.

[0102] In this embodiment, by judging whether the second contour point is a target point based on whether the foot of the perpendicular from the second contour point to the target line is between two first contour points constituting the target line, the efficiency of determining the target point can be improved.

[0103] In another exemplary embodiment, the above step S108 may also be implemented in the following manner:

[0104] Obtain the second foot of the perpendicular from the second contour point in the new second contour to the corresponding target straight line;

[0105] When the second perpendicular foot is located between the first contour points whose corresponding distances meet the preset distance condition, and the distance from the second contour point to the second perpendicular foot is not greater than the preset distance threshold, the second contour point is used as the target point in the new second contour.

[0106] Optionally, in some embodiments, when the terminal does not perform the translation operation on the second contour for the first time, the second perpendicular foot from the second contour point in the current new second contour to the corresponding target straight line can be obtained. When the second perpendicular foot is located between two first contour points whose distance constituting the target straight line meets a preset distance condition, and the distance from the second contour point to the second perpendicular foot is not greater than a preset distance threshold, the currently judged second contour point can be used as the target point in the current new second contour.

[0107] Optionally, in some embodiments, the preset distance threshold can be flexibly set according to the user's usage requirements. For example, when the user requires higher positioning accuracy, the preset distance threshold can be set to be relatively small, thereby increasing the number of repeated translation operations on the second contour, thereby achieving the effect of improving positioning accuracy. When the user requires a faster positioning speed, the preset distance threshold can be set to be relatively large, thereby reducing the number of target points, shortening the time consumed in iterative translation of the second contour, thereby achieving the effect of improving positioning speed.

[0108] In this embodiment, the target point is determined by judging whether the foot of the perpendicular is between the two first contour points closest to the second contour point, and then combining the comparison result of whether the distance from the second contour point to the foot of the perpendicular is greater than the preset distance threshold. This can meet the user's personalized usage needs, allowing the user to flexibly set the preset distance threshold according to their own application scenarios to meet their own needs for higher accuracy or faster speed.

[0109] In an exemplary embodiment, the preset stop condition may include but is not limited to at least one of the following conditions:

[0110] The target point ratio of the new second contour is not greater than the target point ratio of the second contour before the translation.

[0111] The target point ratio of the new second contour is greater than a preset ratio threshold.

[0112] Repeat the operation a number of times up to the iteration threshold.

[0113] Among them, the preset ratio threshold and the iteration number threshold can be flexibly set according to the user's usage requirements.

[0114] Optionally, in some embodiments, after each execution of determining the target points in the second contour, the terminal may calculate the ratio between the number of target points in the second contour and the number of all second contour points in the second contour to obtain the target point ratio of the second contour. When the terminal determines that the target point ratio of the new second contour is not greater than the target point ratio of the second contour before translation, it may be determined that the currently obtained new second contour satisfies the preset stop condition, and the currently obtained new second contour is used as the best iteration result.

[0115] Optionally, in some other implementations, the terminal may also compare the target point ratio of the new second contour after each translation with a preset ratio threshold. When the terminal determines that the target point ratio of the new second contour is greater than the preset ratio threshold, it is determined that the new second contour satisfies the preset stop condition. In addition, the target mark center located by the new second contour can be considered to be located successfully.

[0116] Optionally, in other implementations, the terminal may also compare the number of operations currently executed with the iteration number threshold after each translation operation on the second contour is completed, and when it is determined that the number of repeated operations reaches the iteration number threshold, it is determined that the new second contour meets the preset stop condition, thereby avoiding the iteration from falling into an infinite loop.

[0117] Optionally, in other embodiments, when the terminal determines that the target point ratio of the new second contour is greater than the target point ratio of the second contour before the translation, the translation operation can continue to be performed on the new second contour until the target point ratio of the new second contour is no greater than the target point ratio of the second contour before the translation, or the number of repeated operations reaches an iteration threshold.

[0118] Optionally, in some other embodiments, when the terminal determines that the target point ratio of the new second contour is less than a preset ratio threshold, the translation operation may be continued on the new second contour, thereby increasing the target point ratio of the second contour, until the target point ratio of the new second contour is no greater than the target point ratio of the second contour before the translation, or the number of repeated operations reaches the iteration number threshold.

[0119] Optionally, in other embodiments, when the terminal determines that the target point ratio of the new second contour is greater than the target point ratio of the second contour before translation, and the target point ratio of the new second contour is greater than a preset ratio threshold, the translation operation can continue to be performed on the new second contour until the target point ratio of the new second contour is no greater than the target point ratio of the second contour before translation, or the number of repeated operations reaches an iteration number threshold.

[0120] Optionally, in some embodiments, when the user needs to locate the target mark center faster, the preset ratio threshold can be set to a smaller value to reduce the time spent on repeatedly performing the operation on the second contour, thereby improving the efficiency of the overall target mark center positioning process. When the user needs higher positioning accuracy, the preset ratio threshold can be set to a larger value to increase the number of iterations of repeatedly performing the operation on the second contour, thereby improving the positioning accuracy of the target mark center.

[0121] In this embodiment, by adopting the target point ratio of the new second contour not greater than the target point ratio of the second contour before translation as the preset stop condition, the optimal second contour in the iterative process can be obtained, thereby helping to improve the accuracy of locating the center of the target mark using the translation vector corresponding to the second contour. By adopting the target point ratio of the new second contour greater than the preset ratio threshold as the preset stop condition, the target point ratio of the second contour used to locate the center of the target mark can be increased, thereby helping to improve the positioning accuracy of the center of the target mark. By adopting the number of times the operation is repeatedly executed to reach the iteration number threshold as the preset stop condition, it is possible to avoid the iteration from entering an infinite loop.

[0122] In an exemplary embodiment, Figure 4 As shown, a method for locating a marking center is also provided, including the following steps S402 to S418. Among them:

[0123] Step S402: acquiring a marked image, and sequentially connecting first contour points in the marked image to form a first contour.

[0124] Exemplarily, the terminal may obtain a marked image. A Canny operator is used to perform gradient operation processing on pixels of the marked image to obtain a gradient operation result of the pixel. A first contour point in the marked image is determined according to the gradient operation result of the pixel. A first contour consisting of a plurality of sub-contours is formed by sequentially connecting the first contour points according to the distances of the first contour points.

[0125] Step S404: determining an initial marking center of the first contour according to the first contour points, and rotating the first contour around the initial marking center by a preset angle to obtain a second contour.

[0126] Exemplarily, the terminal may use a minimum circumscribed circle algorithm, such as an algorithm based on convex polygons, a Welzl algorithm (a recursive algorithm), etc., to perform calculations on the coordinates of the first contour point to determine the center of the minimum circumscribed circle of the first contour point. The center of the minimum circumscribed circle of the first contour point is used as the initial marking center of the first contour. The first contour is rotated around the initial marking center by a preset angle to obtain a second contour.

[0127] Step S406 , determining a target segmentation axis from the horizontal axis and the vertical axis according to the first standard deviation corresponding to the horizontal axis coordinate and the second standard deviation corresponding to the vertical axis coordinate of each first contour point.

[0128] Step S408 , dividing each first contour point according to the target segmentation axis and the coordinates of each first contour point on the target segmentation axis to obtain a tree data structure.

[0129] For example, the terminal may use a standard deviation algorithm to calculate the first standard deviation corresponding to the horizontal axis coordinate and the second standard deviation corresponding to the vertical axis coordinate of each first contour point. When the first standard deviation is greater than the second standard deviation, the horizontal axis is used as the target segmentation axis, otherwise the vertical axis is used as the target segmentation axis. Figure 5 As shown, according to the target segmentation axis and the coordinates of each first contour point on the target segmentation axis, the first contour point P1 (X1, Y1) located at the root node is first determined. Then, according to the distances between the remaining first contour points and the first contour point P1 on the target segmentation axis, the first contour point P2 (X2, Y2) is divided into the subnode on the left side of the first contour point P1, and the first contour point P3 (X3, Y3) is divided into the subnode on the right side of the first contour point P1. The first contour point P4 (X4, Y4) is divided into the subnode on the left side of the first contour point P2, and the first contour point P5 (X5, Y5) is divided into the subnode on the right side of the first contour point P2. The first contour point P8 (X8, Y8) is divided into the subnode on the left side of the first contour point P4. The first contour point P6 (X6, Y6) is divided into a child node on the left side of the first contour point P3, and the first contour point P7 (X7, Y7) is divided into a child node on the right side of the first contour point P3, forming a tree data structure.

[0130] Step S410, using a tree data structure to query and obtain a first contour point whose distance to the second contour point meets a preset distance condition, and determining a target straight line where the first contour point whose distance meets the preset distance condition is located.

[0131] Optionally, in some implementations, when the terminal performs an operation on the second contour for the first time, the current second contour may be downsampled, and a second contour point may be selected every 5 points. The tree data structure of the first contour is used to query and obtain the two first contour points closest to each second contour point, and the two first contour points that meet the preset distance condition are used to construct the target straight line.

[0132] Optionally, in other embodiments, when the terminal is not performing an operation on the second contour for the first time, all points in the second contour can be used as second contour points, and corresponding first contour points that meet preset distance conditions can be queried from the tree data structure of the first contour to construct a target straight line.

[0133] Step S412, determining the target point in the second contour according to the positional relationship between the second contour point and the target straight line.

[0134] Optionally, in some embodiments, Figure 6 As shown, point P is the second contour point. Points P1 and P2 are first contour points whose distances from the second contour point P meet the preset distance threshold. Point C is the foot of the perpendicular from point P to the target straight line where points P1P2 are located. D is the distance from the second contour point P to the target straight line P1P2.

[0135] When the terminal performs an operation on the second contour for the first time, it can determine whether the second contour point P is a target point based on whether the foot C of the perpendicular from the second contour point P to the target straight line P1P2 is between the first contour points P1 and P2 that meet the preset distance condition.

[0136] When the terminal is not performing an operation on the second contour for the first time, it can determine whether the second contour point P is the target point based on whether the foot C of the perpendicular from the second contour point P to the target straight line P1P2 is between the first contour points P1 and P2 that meet the preset distance condition, and then determine whether the distance D from the second contour point P to the target straight line P1P2 is greater than the preset distance threshold.

[0137] Step S414: Generate a translation vector using the direction vector from the target point to the corresponding target straight line, and translate the second contour according to the translation vector to obtain a new second contour.

[0138] Exemplarily, the terminal can construct a direction vector corresponding to each target point using the target point and the foot of the perpendicular from the target point to the corresponding target straight line. Decompose the direction vector of each target point into a first component in the horizontal axis direction and a second component in the vertical axis direction. Generate a corresponding horizontal axis translation using the first component of each target point, and generate a corresponding vertical axis translation using the second component of each target point. Generate corresponding translation coordinates using the horizontal axis translation and the vertical axis translation. Translate the second contour according to the translation vector to obtain a new second contour.

[0139] Optionally, in some implementations, the translation vector may be calculated using the following formula:

[0140] ,

[0141] Among them, V Mean represents the translation vector, V ix Represents the first component of the direction vector of the i-th target point, V iy Represents the second component of the direction vector of the i-th target point, where i represents the number of the direction vectors of the target point.

[0142] Optionally, in some embodiments, Figure 7 As shown in FIG. 1 , if there is dirt, pollution or noise in the marked image, the first contour points extracted may include redundant contour points and erroneous contour points. Figure 7 The second contour obtained by rotating the first contour in around the initial marking center will appear as follows Figure 8 As shown in the case: the redundant contour points have no corresponding contours near the first contour after rotation, and the erroneous contour points have a certain distance from the remaining first contour points after rotation. By adopting the technical means in the above step S412, after extracting the target point, the second contour points that are not target points in the second contour can be filtered out and do not participate in the subsequent calculation. This avoids the influence of redundant contour points and erroneous contour points on the subsequent target mark center positioning, and improves the anti-interference performance of the mark center positioning method.

[0143] Step S416, determining whether the new second contour satisfies a preset stop condition.

[0144] Exemplarily, after the translation, the terminal may determine whether the target point ratio of the new second contour is greater than the target point ratio of the second contour before the translation, and at the same time, determine whether the target point ratio of the new second contour is greater than a preset ratio threshold.

[0145] When the target point ratio of the new second contour is greater than the target point ratio of the second contour before translation, the above steps S410 to S414 are repeated to translate the new second contour until the number of repeated operations reaches the iteration number threshold, or the target point ratio of the new second contour is not greater than the target point ratio of the second contour before translation.

[0146] If the target point ratio of the new second contour is greater than the preset ratio threshold, it indicates that the current marker center positioning is successful. If the target point ratio of the new second contour is less than the preset ratio threshold, it indicates that the current marker center positioning fails, and the above steps S410 to S414 need to be repeated until the number of repeated operations reaches the iteration number threshold, or the target point ratio of the new second contour is not greater than the target point ratio of the second contour before translation.

[0147] Step S418: locate the target marking center of the marking image according to the initial marking center and the translation vector.

[0148] Exemplarily, the terminal may perform superposition based on the initial marking center and the translation vector used in each second outline translation process, and use the superimposed initial marking center as the target marking center of the marking image.

[0149] In this embodiment, the target mark center is located in the above-mentioned manner based on the central symmetry of the mark, and there is no requirement for the fill color of the mark, the line composition of the mark, or the style of the mark, so that it can be applied to different types of mark images and has higher robustness. By providing a preset distance threshold and a preset ratio threshold for the user to flexibly set, it can meet the user's requirements for accuracy and efficiency in different application scenarios, and improve the flexibility of the mark center positioning method. In addition, since only the target point is used for subsequent mark center positioning calculations in this solution, it can also avoid the influence of dirt, pollution, noise, etc. on the extraction of the first contour point, so that the mark center positioning method has stronger anti-interference and compatibility.

[0150] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0151] Based on the same inventive concept, the embodiment of the present application also provides a device for positioning the marking center for implementing the above-mentioned method for positioning the marking center. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific definition in the embodiment of the device for positioning the marking center provided below can refer to the definition of the method for positioning the marking center above, and will not be repeated here.

[0152] In an exemplary embodiment, Fig. 9 As shown, a marking center positioning device 900 is provided, comprising: a contour extraction module 902, a contour rotation module 904, an iterative adjustment module 906 and a center positioning module 908, wherein:

[0153] The contour extraction module 902 is used to obtain the marked image and sequentially connect the first contour points in the marked image to form a first contour.

[0154] The contour rotation module 904 is used to determine the initial marking center of the first contour according to the first contour points, and rotate the first contour around the initial marking center by a preset angle to obtain a second contour.

[0155] The iterative adjustment module 906 is used to repeatedly perform the following operations on the second contour: query from the first contour to obtain a first contour point whose distance to the second contour point in the second contour satisfies a preset distance condition, determine a target straight line where the first contour point whose distance satisfies the preset distance condition is located, determine the target point in the second contour according to the positional relationship between the second contour point and the target straight line, generate a translation vector using the direction vector from the target point to the corresponding target straight line, and translate the second contour according to the translation vector to obtain a new second contour, until the new second contour meets the preset stop condition.

[0156] The center positioning module 908 is used to locate the target marking center of the marking image according to the initial marking center and the translation vector.

[0157] In an exemplary embodiment, the iterative adjustment module 906 includes: a downsampling unit, which is used to downsample the second contour to obtain a second contour point in the second contour; a structure acquisition unit, which is used to obtain a tree data structure corresponding to the first contour; a tree query unit, which is used to use the tree data structure to query and obtain a first contour point whose distance to the second contour point meets a preset distance condition; and a straight line determination unit, which is used to determine a target straight line where the first contour point whose distance meets the preset distance condition is located.

[0158] In an exemplary embodiment, the structure acquisition unit is also used to obtain the first standard deviation corresponding to the horizontal axis coordinate of each first contour point, and the second standard deviation corresponding to the vertical axis coordinate of each first contour point; determine the target segmentation axis from the horizontal axis and the vertical axis based on the comparison result of the first standard deviation and the second standard deviation; divide each first contour point according to the target segmentation axis and the coordinates of each first contour point on the target segmentation axis to obtain a tree data structure.

[0159] In an exemplary embodiment, the preset stop condition includes at least one of the following conditions: the target point ratio of the new second contour is not greater than the target point ratio of the second contour before translation; the target point ratio of the new second contour is greater than a preset ratio threshold; the number of repeated operations reaches an iteration number threshold.

[0160] In an exemplary embodiment, the iterative adjustment module 906 is further configured to obtain the foot of a first perpendicular from the second contour point to the target straight line; when the foot of the first perpendicular is located between the first contour points whose distances meet a preset distance condition, the second contour point is used as the target point.

[0161] In an exemplary embodiment, the iterative adjustment module 906 is also used to obtain the second foot of a perpendicular from a second contour point in the new second contour to the corresponding target straight line; when the second foot of a perpendicular is located between corresponding first contour points whose distances satisfy a preset distance condition, and the distance from the second contour point to the second foot of a perpendicular is not greater than a preset distance threshold, the second contour point is used as the target point in the new second contour.

[0162] Each module in the above-mentioned marking center positioning device 900 can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0163] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Fig.10As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, a method for locating a marking center is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0164] Those skilled in the art will understand that Fig.10 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0165] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0166] In an exemplary embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0167] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0168] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0169] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0170] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for locating a marking center, characterized in that: The method comprises: Acquire a mark image, and sequentially connect first contour points in the mark image to form a first contour, wherein the mark image is used to represent an image acquired from a mark with central symmetry on a wafer; Determine an initial marking center of the first contour according to the first contour point, and rotate the first contour around the initial marking center by a preset angle to obtain a second contour, wherein the preset angle is determined based on the central symmetry of the mark; Repeat the following steps for the second profile: Querying from the first contour to obtain a first contour point whose distance from the second contour point in the second contour satisfies a preset distance condition, determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located, Determine the target point in the second contour according to the positional relationship between the second contour point and the target straight line, A translation vector is generated by using the direction vector from the target point to the corresponding target straight line, and the second contour is translated according to the translation vector to obtain a new second contour, until the new second profile meets a preset stop condition; According to the initial marking center and the translation vector, a target marking center of the marking image is located, and the target marking center is used to represent the rotation center of the output marking; The querying from the first contour to obtain a first contour point whose distance to the second contour point in the second contour satisfies a preset distance condition, and determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located comprises: Performing downsampling processing on the second contour to obtain second contour points in the second contour; Acquire a tree data structure corresponding to the first contour; Using the tree data structure to query and obtain a first contour point whose distance to the second contour point meets a preset distance condition; A target straight line is determined where a first contour point whose distance satisfies a preset distance condition is located.

2. The method according to claim 1, characterized in that The generation method of the tree data structure includes: Obtaining a first standard deviation corresponding to the horizontal axis coordinate of each of the first contour points, and a second standard deviation corresponding to the vertical axis coordinate of each of the first contour points; Determining a target segmentation axis from a horizontal axis and a vertical axis according to a comparison result of the first standard deviation and the second standard deviation; Each of the first contour points is divided according to the target segmentation axis and the coordinates of each of the first contour points on the target segmentation axis to obtain the tree data structure.

3. The method according to any one of claims 1 to 2, characterized in that The preset stop condition includes at least one of the following conditions: The target point ratio of the new second contour is not greater than the target point ratio of the second contour before translation; The target point ratio of the new second contour is greater than a preset ratio threshold; Repeat the operation a number of times up to the iteration threshold.

4. The method according to any one of claims 1 to 2, characterized in that The step of determining the target point in the second contour according to the positional relationship between the second contour point and the target straight line includes: Acquire a first perpendicular foot from the second contour point to the target straight line; When the first perpendicular foot is located between the first contour points whose distances satisfy a preset distance condition, the second contour point is used as the target point.

5. The method according to any one of claims 1 to 2, characterized in that The step of determining the target point in the second contour according to the positional relationship between the second contour point and the target straight line includes: Acquire a second perpendicular foot from a second contour point in the new second contour to the corresponding target straight line; When the second perpendicular foot is located between the corresponding first contour points whose distances meet a preset distance condition, and the distance from the second contour point to the second perpendicular foot is not greater than a preset distance threshold, the second contour point is used as a target point in the new second contour.

6. A positioning device for marking a center, characterized in that: The device comprises: A contour extraction module, used for acquiring a marker image and sequentially connecting first contour points in the marker image to form a first contour, wherein the marker image is used to represent an image acquired from a marker with central symmetry on a wafer; A contour rotation module, used to determine an initial marking center of the first contour according to the first contour point, and rotate the first contour around the initial marking center by a preset angle to obtain a second contour, wherein the preset angle is determined based on the central symmetry of the mark; an iterative adjustment module, configured to repeatedly perform the following operations on the second contour: querying from the first contour to obtain a first contour point whose distance from a second contour point in the second contour satisfies a preset distance condition, determining a target straight line where the first contour point whose distance satisfies the preset distance condition is located, determining a target point in the second contour according to a positional relationship between the second contour point and the target straight line, generating a translation vector using a direction vector from the target point to the corresponding target straight line, and translating the second contour according to the translation vector to obtain a new second contour, until the new second contour satisfies a preset stop condition; A center positioning module, used for positioning a target marking center of the marking image according to the initial marking center and the translation vector, wherein the target marking center is used to represent a rotation center of an output marking; Wherein, the iterative adjustment module includes: A down-sampling unit, configured to perform down-sampling processing on the second contour to obtain second contour points in the second contour; A structure acquisition unit, used to acquire a tree data structure corresponding to the first profile; A tree query unit, configured to query using the tree data structure to obtain a first contour point whose distance to the second contour point satisfies a preset distance condition; The straight line determination unit is used to determine the target straight line where the first contour point whose distance meets the preset distance condition is located.

7. The device according to claim 6, characterized in that The structure acquisition unit is further used for: Obtaining a first standard deviation corresponding to the horizontal axis coordinate of each of the first contour points, and a second standard deviation corresponding to the vertical axis coordinate of each of the first contour points; Determining a target segmentation axis from a horizontal axis and a vertical axis according to a comparison result of the first standard deviation and the second standard deviation; Each of the first contour points is divided according to the target segmentation axis and the coordinates of each of the first contour points on the target segmentation axis to obtain the tree data structure.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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