Weld joint extraction method and system based on three-dimensional geometric feature analysis

Abstract

The embodiment of the invention provides a welding seam extraction method based on three-dimensional geometric feature analysis, and the method comprises the steps: obtaining a target three-dimensional model, and obtaining a contour line set based on the geometric Boolean intersection of each independent entity in the target three-dimensional model; performing screening treatment on the contour line set to obtain a welding seam set, wherein the screening treatment comprises first screening, segmentation treatment and second screening; determining a plurality of vertical weld joints and a plurality of flat weld joints based on the coordinate difference values of all the weld joints in the weld joint set in the preset direction; determining flat welding parameters of a plurality of flat welding seams; and determining vertical welding parameters based on the flat welding parameters, the plurality of vertical welding seams and the topological correlation of the plurality of flat welding seams.

Description

TECHNICAL FIELD

[0001] The present specification relates to the technical field of automated welding, and in particular to a welding seam extraction method and system based on three-dimensional geometric feature analysis. BACKGROUND

[0002] Existing welding seam extraction methods usually rely on three-dimensional models to pre-establish welding seam information in the modeling stage, that is, in the modeling process, the welding seam position, type or related parameters are stored as model attributes through manual annotation or specific modeling specifications, and when the model is analyzed, the welding seam information is obtained by directly reading the pre-set welding seam attributes in the model. However, such methods have a high dependence on modeling processes and the integrity of model data, often requiring uniform model sources and consistent modeling standards, which limits the scope of application and has poor versatility.

[0003] In actual engineering applications, three-dimensional models can come from different design software or different historical projects, and some models do not contain welding seam information in the design stage, or the welding seam attributes are lost in the model conversion, format compression or data interaction process, resulting in the model no longer having directly readable welding seam attributes. In the above cases, the existing welding seam extraction method cannot effectively identify the welding seam position and related information, making it difficult to meet the application requirements of welding process planning, welding quality evaluation and automated welding.

[0004] Therefore, there is an urgent need for a welding seam extraction method and system based on three-dimensional geometric feature analysis, which can identify and extract welding seams based only on the geometric features of the model itself without relying on pre-set welding seam attribute information in the three-dimensional model, to solve the problem that the existing technology cannot obtain welding seam information when the three-dimensional model does not contain welding seam information. SUMMARY

[0005] One or more embodiments of the present specification provide a welding seam extraction method based on three-dimensional geometric feature analysis, comprising: obtaining a target three-dimensional model, obtaining a contour line set based on the geometric Boolean intersection of each independent entity in the target three-dimensional model; performing screening processing on the contour line set to obtain a welding seam set, the screening processing including first screening, segmentation processing and second screening, wherein the first screening and the second screening correspond to different screening objects; determining a plurality of vertical welding seams and a plurality of horizontal welding seams based on the coordinate difference of each welding seam in the welding seam set in a preset direction; determining horizontal welding parameters of the plurality of horizontal welding seams; determining vertical welding parameters based on the horizontal welding parameters, the plurality of vertical welding seams and the topological association of the plurality of horizontal welding seams.

[0006] One or more embodiments of the present specification provide a weld extraction system based on three-dimensional geometric feature analysis, comprising: an acquisition module configured to: acquire a target three-dimensional model, and obtain a contour line set based on a geometric Boolean intersection of each independent entity in the target three-dimensional model; a screening module configured to: perform screening processing on the contour line set to obtain a weld set, the screening processing comprising a first screening, a segmentation processing, and a second screening, wherein the first screening and the second screening correspond to different screening objects; a parameter determination module configured to: determine a plurality of vertical welds and a plurality of horizontal welds based on coordinate difference values of each weld in the weld set in a preset direction; determine horizontal welding parameters of the plurality of horizontal welds; and determine vertical welding parameters based on the horizontal welding parameters, a topological association of the plurality of vertical welds and the plurality of horizontal welds.

[0007] One or more embodiments of the present specification provide a weld extraction device based on three-dimensional geometric feature analysis, comprising a processor configured to execute the above-described weld extraction method based on three-dimensional geometric feature analysis.

[0008] One or more embodiments of the present specification provide a computer-readable storage medium storing computer instructions, when a computer reads the computer instructions in the storage medium, the computer executes the above-described weld extraction method based on three-dimensional geometric feature analysis. BRIEF DESCRIPTION OF DRAWINGS

[0009] The present specification will be further illustrated in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, the same numbers represent the same structures, wherein: Figure 1 is an exemplary module diagram of a weld extraction system based on three-dimensional geometric feature analysis according to some embodiments of the present specification; Figure 2 is an exemplary flowchart of a weld extraction method based on three-dimensional geometric feature analysis according to some embodiments of the present specification; Figure 3 is an exemplary flowchart of obtaining a weld set according to some embodiments of the present specification; Figure 4 is an exemplary schematic diagram of determining vertical welding parameters according to some embodiments of the present specification; Figure 5 is an exemplary schematic diagram of determining horizontal welding parameters according to some embodiments of the present specification. DETAILED DESCRIPTION

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present specification, the drawings needed to be used in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some examples or embodiments of the present specification, and for those skilled in the art, the present specification can also be applied to other similar scenarios without creative labor on the basis of these drawings. Unless it is clear from the language environment or otherwise stated, the same reference numbers in the drawings represent the same structures or operations.

[0011] It should be understood that the "system", "device", "unit" and / or "module" used herein is a method for distinguishing different components, elements, parts, sections or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0012] As shown in the specification and claims, unless the context clearly indicates otherwise, the words "one", "a", "an", and / or "the" do not refer to the singular, but can also include the plural. Generally, the terms "comprise" and "include" only indicate the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements.

[0013] Flowcharts are used in the present specification to illustrate the operations performed by the system according to the embodiments of the present specification. It should be understood that the preceding or subsequent operations are not necessarily performed in sequence. On the contrary, each step can be processed in reverse order or simultaneously. At the same time, other operations can be added to these processes, or one or more steps of the operation can be removed from these processes.

[0014] Figure 1 is an exemplary module diagram of a weld extraction system based on three-dimensional geometric feature analysis according to some embodiments of the present specification.

[0015] Some embodiments of the present specification provide a weld extraction system based on three-dimensional geometric feature analysis (hereinafter referred to as a weld extraction system). The weld extraction system 100 can include an acquisition module 110, a screening module 120 and a parameter determination module 130.

[0016] In some embodiments, the acquisition module 110, the screening module 120 and the parameter determination module 130 are communicatively connected. Exemplary communication connection methods include, but are not limited to, Bluetooth, WIFI, 5G, etc.

[0017] In some embodiments, the acquisition module 110, the screening module 120 and the parameter determination module 130 can have their own processors, or can share a processor.

[0018] The processor can process data and / or information obtained from other devices or system components. The processor can execute program instructions based on this data, information, and / or processing results to perform one or more functions described in this application. In some embodiments, the processor can include one or more sub-processing devices (e.g., single-core processing devices or multi-core multi-thread processing devices). For example only, the processor can include a central processor, a controller, a microprocessor, etc., or any combination thereof.

[0019] The acquisition module 110 refers to a module for acquiring a target three-dimensional model and a contour line set.

[0020] In some embodiments, the acquisition module is configured to acquire the target three-dimensional model, and obtain the contour line set based on a geometric Boolean intersection of each independent entity in the target three-dimensional model.

[0021] The screening module 120 refers to a module for screening and segmenting the contour line set.

[0022] In some embodiments, the screening module is configured to perform a screening process on the contour line set to obtain a weld seam set, the screening process including a first screening, a segmentation process, and a second screening, wherein the first screening and the second screening correspond to different screening objects.

[0023] In some embodiments, the screening module is further configured to perform the first screening on the contour line set to obtain an initial line segment set; perform the following operations on each initial line segment in the initial line segment set: detecting an intersection relationship of the initial line segment with the remaining initial line segments in the initial line segment set; when the intersection relationship is an interior point intersection, segmenting the initial line segment into a plurality of sub-line segments based on the intersection point; constructing a segmented line segment set based on the initial line segment set and the plurality of sub-line segments; and performing the second screening on the segmented line segment set to obtain the weld seam set.

[0024] In some embodiments, the screening module is further configured to: construct a length distribution graph by counting lengths of all contour lines in the contour line set; determine a dynamic screening threshold based on a plate thickness noise peak and a weld seam signal peak in the length distribution graph; and remove contour lines with lengths less than the dynamic screening threshold from the contour line set to obtain the initial line segment set.

[0025] The parameter determination module 130 refers to a module for determining flat welding parameters and vertical welding parameters.

[0026] In some embodiments, the parameter determination module is configured to: determine a plurality of vertical weld seams and a plurality of flat weld seams based on coordinate difference values of each weld seam in the weld seam set in a preset direction; determine the flat welding parameters of the plurality of flat weld seams; and determine the vertical welding parameters based on the flat welding parameters, topological correlations of the plurality of vertical weld seams and the plurality of flat weld seams.

[0027] In some embodiments, the parameter determining module is further configured to: for each of the plurality of fillet welds, construct a perpendicular vector corresponding to the fillet weld, the perpendicular vector passing through a midpoint of the fillet weld; extend the perpendicular vector to a total length of the perpendicular vector exceeding a preset plate thickness; in response to the perpendicular vector not intersecting a parallel boundary line of an independent entity to which the fillet weld belongs, maintain a scanning direction of the fillet weld; and in response to the perpendicular vector intersecting the parallel boundary line of the independent entity to which the fillet weld belongs, exchange the scanning direction of the fillet weld.

[0028] For more information about the weld extraction system and its modules, please refer to Figures 2-5 and the related descriptions thereof.

[0029] It should be noted that the above description of the weld extraction system and its modules is for the convenience of description only, and cannot limit the scope of the embodiments. It can be understood that, for those skilled in the art, after understanding the principles of the system, the modules can be combined arbitrarily or connected with other modules to form a subsystem without departing from the principles. In some embodiments, Figure 1 The acquisition module 110, the screening module 120 and the parameter determining module 130 disclosed in the specification can be different modules in a system, or can be a module to realize the functions of two or more modules described above. For example, the modules can share a storage module, and the modules can also have their own storage modules. Variations such as this are within the scope of protection of the specification.

[0030] Figure 2 is an exemplary flowchart of a weld extraction method based on three-dimensional geometric feature analysis according to some embodiments of the specification. As Figure 2 shown, the flowchart 200 includes the following steps 210-250. In some embodiments, the flowchart 200 can be executed by the weld extraction system.

[0031] Step 210: Acquire a target three-dimensional model, and obtain a set of contour lines based on a geometric Boolean intersection of each independent entity in the target three-dimensional model.

[0032] In some embodiments, step 210 can be executed by the acquisition module. For more information about the acquisition module, please refer to Figure 1 and the related descriptions thereof.

[0033] The target three-dimensional model refers to a digital three-dimensional model representing the geometric shape, size parameters and spatial position relationship of a welded component. For example, a Computer-Aided Design (CAD) model of the welded component.

[0034] The welded component refers to an overall structure formed by welding a plurality of components.

[0035] In some embodiments, the target three-dimensional model can be a three-dimensional model of an H-shaped steel and its accessory components. The accessory components include wing plates, web plates, and rib plates, etc.

[0036] In some embodiments, the obtaining module can obtain the target three-dimensional model through an imported design file or three-dimensional scanning data.

[0037] In some embodiments, the obtaining module can select three non-collinear points on the maximum plane in the target three-dimensional model to determine the spatial position and normal direction of the maximum plane, and establish a three-dimensional coordinate system with the maximum plane as the reference, wherein the two mutually perpendicular directions in the maximum plane are taken as the X-axis and the Y-axis respectively, and the normal direction perpendicular to the maximum plane is taken as the Z-axis; then, based on the established three-dimensional coordinate system, the position and pose of the target three-dimensional model are uniformly converted to facilitate subsequent geometric operations.

[0038] An independent entity refers to a single component that constitutes a welding component in the target three-dimensional model. For example, when the target three-dimensional model is a three-dimensional model of an H-shaped steel and its accessory components, each wing plate, web plate, and rib plate in the H-shaped steel is an independent entity.

[0039] A geometric Boolean intersection refers to the common geometric part obtained by performing a Boolean intersection operation on two or more independent entities in the target three-dimensional model. In some embodiments, the geometric Boolean intersection can be manifested as a common line segment or a set of common line segments formed at the position where the two independent entities contact or penetrate each other.

[0040] A set of contour lines refers to a set formed by all contour lines in the common geometric part obtained by the geometric Boolean intersection between each independent entity in the target three-dimensional model. The contour line is a line segment.

[0041] In some embodiments, the obtaining module can perform a geometric Boolean intersection operation on each pair of independent entities in the target three-dimensional model, extract the contour lines of the common geometric part, and uniformly collect all contour lines of the common geometric part to form a set of contour lines.

[0042] Step 220: performing a screening process on the set of contour lines to obtain a set of welds.

[0043] In some embodiments, step 220 can be performed by a screening module. For more information about the screening module, see Figure 1 and related descriptions.

[0044] The screening process refers to a step-by-step screening and segmentation process on each contour line in the set of contour lines to exclude non-weld contour lines and retain contour lines corresponding to welds.

[0045] In some embodiments, the screening process comprises a first screening, a segmentation process, and a second screening, wherein the first screening and the second screening correspond to different screening objects. The screening object refers to the set to be screened.

[0046] For more information about the first screening and the second screening, see Figure 3 and the related description.

[0047] The segmentation process refers to the process of splitting the line segment into a plurality of continuous sub-line segments.

[0048] The set of weld seams refers to the set of line segments obtained after the set of contour lines is subjected to the screening process.

[0049] In some embodiments, each line segment in the set of weld seams is a contour line corresponding to an actual welding position in the target three-dimensional model, and therefore the line segment in the set of weld seams is also referred to as a weld seam. For more information about obtaining the set of weld seams, see Figure 3 and the related description.

[0050] In step 230, a plurality of vertical weld seams and a plurality of horizontal weld seams are determined based on the coordinate difference of each weld seam in the set of weld seams in a preset direction.

[0051] In some embodiments, step 230 can be performed by a parameter determination module. For more information about the parameter determination module, see Figure 1 and the related description.

[0052] The preset direction refers to a reference direction preset in the target three-dimensional model.

[0053] In some embodiments, the preset direction can be preset by a person skilled in the art.

[0054] In some embodiments, the preset direction can be the Z-axis direction of the three-dimensional coordinate system, i.e., the normal direction of the largest plane in the target three-dimensional model.

[0055] The vertical weld seam refers to a weld seam with a welding direction in the vertical plane.

[0056] The horizontal weld seam refers to a weld seam with a welding direction in the horizontal plane.

[0057] In some embodiments, the parameter determination module can distinguish the vertical weld seam and the horizontal weld seam based on the coordinate difference of the two end points of each weld seam in the set of weld seams in the preset direction. For example, when the coordinate difference of the two end points of a certain weld seam in the Z-axis direction is greater than a preset threshold, the weld seam is determined to be a vertical weld seam; when the coordinate difference of the two end points of a certain weld seam in the Z-axis direction is less than or equal to the preset threshold, the weld seam is determined to be a horizontal weld seam. The preset threshold is preset by a person. For example, the preset threshold can be 50 mm.

[0058] In step 240, the horizontal welding parameters of the plurality of horizontal weld seams are determined.

[0059] In some embodiments, step 240 can be performed by the parameter determination module.

[0060] The flat welding parameter refers to a parameter used to guide the welding equipment to perform flat weld welding.

[0061] In some embodiments, the flat welding parameter includes a scanning direction and a scanning angle of the flat weld.

[0062] The scanning direction refers to the direction in which the welding equipment moves along the flat weld. The welding equipment refers to an automated or semi-automated device used to perform welding work, such as a welding robot, a welding mechanical arm, or a numerical control welding equipment, etc.

[0063] In some embodiments, the scanning direction can be a direction from the starting point to the ending point of the flat weld.

[0064] The scanning angle refers to the spatial orientation of the visual sensor relative to the independent entity to which the flat weld belongs when collecting data on the flat weld. In some embodiments, the scanning angle is used to represent the positional relationship of the visual sensor on which side of the independent entity to which the flat weld belongs. For example, the scanning angle can be on the left or right side of the independent entity to which the flat weld belongs. Wherein, the independent entity to which the flat weld belongs can be determined according to the target three-dimensional model.

[0065] In some embodiments, for each flat weld, the parameter determination module can select one of the two endpoints of the flat weld as the starting point and the other as the ending point to determine the scanning direction; since the welding equipment always maintains a fixed movement direction (e.g., from left to right) in the scanning direction, after the scanning direction is determined, the scanning angle corresponding to the scanning direction and the independent entity to which the flat weld belongs is further determined to obtain the flat welding parameter.

[0066] For more information on determining the flat welding parameter, see Figure 5 and the related description.

[0067] Step 250, based on the flat welding parameter, the plurality of vertical welds, and the topological association of the plurality of flat welds, determine the vertical welding parameter.

[0068] In some embodiments, step 250 can be performed by the parameter determination module.

[0069] The topological association refers to the connection relationship and positional relationship between all line segments in the target three-dimensional model.

[0070] The connection relationship refers to whether the line segments are connected to each other.

[0071] The positional relationship refers to whether the line segments are located in the same plane and whether they belong to the same independent entity.

[0072] In some embodiments, the topological association can be determined according to the target three-dimensional model.

[0073] The vertical welding parameter refers to a parameter used to guide the welding equipment to perform the vertical welding of the weld.

[0074] In some embodiments, the vertical welding parameter comprises a scanning direction.

[0075] In some embodiments, assuming that there is a determined direction flat weld on the plane where each vertical weld is located, the parameter determination module can determine the vertical welding parameter based on the scanning direction of the determined direction flat weld and the topological association thereof with the vertical weld. For example, there is a determined direction flat weld A on the plane where a vertical weld B is located, the scanning direction of the flat weld A is → According to the topological association, the flat weld A and the vertical weld B are connected by a line segment C , , and the connection order is: → → → → → Now that the scanning direction of the flat weld is → , the scanning direction of the vertical weld can be obtained as → , i.e., the vertical welding parameter of the vertical weld B is determined. Wherein, , are two end points of the flat weld A, respectively; and are two end points of the line segment C, respectively; and are two end points of the vertical weld B, respectively.

[0076] For more information on how to determine the vertical welding parameter when there are multiple flat welds with determined direction on the plane where the vertical weld is located, see Figure 4 and the related description thereof.

[0077] In some embodiments of the present specification, by automatic geometric feature extraction and topological association analysis, the positions of the welds can be accurately identified from the target three-dimensional model without manual intervention, and the welding parameters of various types of welds can be planned, thereby improving the efficiency and accuracy of the welding programming.

[0078] Figure 3 is an exemplary flowchart for obtaining a set of welds according to some embodiments of the present specification. As shown in Figure 3 , the flow 300 comprises the following steps 310-340. In some embodiments, the flow 300 can be performed by the screening module. For more information on the screening module, see​​Figure 1 and related descriptions thereof.

[0079] At step 310, a first screening is performed on the set of contour lines to obtain a set of initial line segments.

[0080] For more details about the set of contour lines, see Figure 2 and related descriptions thereof.

[0081] The first screening refers to a preliminary filtering of the contour lines in the set of contour lines to eliminate contour lines that are too short in length.

[0082] In some embodiments, the screening object of the first screening is the set of contour lines.

[0083] The set of initial line segments refers to a set of line segments obtained after the set of contour lines is screened by the first screening. In some embodiments, the set of initial line segments includes a plurality of initial line segments.

[0084] In some embodiments, the screening module eliminates contour lines in the set of contour lines that are shorter than a preset length threshold from the set of contour lines to obtain the set of initial line segments.

[0085] The preset length threshold refers to a reference threshold used to determine whether a contour line is retained when performing the first screening. In some embodiments, the specific length of the preset length threshold can be preset by a human.

[0086] Since the plate thickness parameters and modeling accuracy of each independent entity may vary in different target three-dimensional models, the length distribution characteristics of the contour lines also change accordingly. If a fixed preset length threshold is used for the first screening, it is difficult to simultaneously adapt to target three-dimensional models with different plate thickness conditions or modeling errors, especially when the target three-dimensional model includes multiple plate thicknesses. In this case, a fixed threshold value is likely to mistakenly retain noise line segments that should be eliminated or misjudge contour lines corresponding to welds as noise line segments, thereby affecting the screening effect. Therefore, in some embodiments, the screening module can perform the first screening based on a dynamic screening threshold.

[0087] Noise line segments refer to contour lines that exist in the set of contour lines but do not correspond to actual welding positions in the target three-dimensional model. For example, plate thickness lines. Plate thickness lines refer to contour lines formed in the plate thickness direction of a component.

[0088] In some embodiments, in order to adapt to the changes in the length distribution of contour lines under different plate thickness and modeling error conditions and avoid weld detection omission or misjudgment caused by fixed threshold screening, the first screening includes: counting the lengths of all contour lines in the set of contour lines to construct a length distribution graph; determining a dynamic screening threshold based on plate thickness noise peaks and weld signal peaks in the length distribution graph; eliminating contour lines shorter than the dynamic screening threshold from the set of contour lines to obtain the set of initial line segments.

[0089] In some embodiments, the screening module can calculate the Euclidean distance between two end points of a contour line in the target 3D model as the length of the contour line according to the coordinate values of the two end points. For more information about the target 3D model, see Figure 2 and the related description.

[0090] The length distribution diagram refers to a histogram obtained by counting the lengths of the contour lines in the contour line set. In some embodiments, the horizontal axis of the length distribution diagram represents the contour line length interval, and the vertical axis represents the number of contour lines in the corresponding length interval.

[0091] In some embodiments, the screening module first obtains the length information of each contour line in the contour line set, and divides the contour line lengths into multiple length intervals; then, each contour line is assigned to the corresponding length interval, and the number of contour lines in each length interval is counted to construct a length distribution histogram.

[0092] The source of the contour line set is all contour lines of the common geometric part formed by performing geometric Boolean intersection between each independent entity in the target 3D model. These contour lines have obvious differences in geometric origin and length scale. Part of the contour lines correspond to the contour lines formed by the intersection of each independent entity in the thickness direction, i.e., the thickness line, whose length is constrained by the thickness dimension and the value is small. Another part of the contour lines correspond to the contour lines formed by the fit of each independent entity along its extension direction, i.e., the weld, whose length is determined by the overall size of the independent entity and its value is significantly greater than the length of the thickness line. Therefore, when counting the lengths of the contour lines in the contour line set, the length distribution histogram will show two obvious peaks, i.e., the "bimodal" distribution characteristic.

[0093] The thickness noise peak refers to the peak on the left side of the length distribution diagram.

[0094] In some embodiments, the contour lines in the region corresponding to the thickness noise peak are all noise line segments, and there is no weld.

[0095] The weld signal peak refers to the peak on the right side of the length distribution diagram.

[0096] The dynamic screening threshold refers to the reference value for distinguishing noise line segments and welds from the contour line set.

[0097] In some implementations, the dynamic screening threshold is the valley value between the thickness noise peak and the weld signal peak in the length distribution diagram.

[0098] In some embodiments, the screening module can calculate the dynamic screening threshold based on the Otsu algorithm by setting the thickness noise peak as the foreground pixel and the weld signal peak as the background pixel.

[0099] In some embodiments, the screening module eliminates the profile lines in the profile line set with a length less than the dynamic screening threshold, and the remaining profile lines constitute the initial line segment set.

[0100] In some embodiments of the present specification, by statistically analyzing the length of each profile line in the profile line set, a length distribution graph is constructed, and a dynamic screening threshold is determined based on the plate thickness noise peak and the weld signal peak in the length distribution graph, thereby overcoming the defect that it is difficult to consider different plate thickness conditions or modeling errors when using a fixed threshold. This method can dynamically adjust the screening criteria according to the actual data characteristics, effectively distinguish welds and noise line segments, and significantly reduce the missed detection rate and false detection rate in the weld extraction process.

[0101] In some embodiments, in order to avoid the problem that local welds are misjudged when a global length distribution histogram is used when the component size of the H-shaped steel differs greatly, for example, one end of the H-shaped steel is a large rib plate (20 mm thick, 500 mm long), and the other end is a small rib plate (6 mm thick, 30 mm long). If a global length distribution graph is used, the 30 mm long weld of the small rib plate may be eliminated as 20 mm plate thickness noise of the large rib plate. Before the screening module constructs the length distribution graph, the first screening further includes: based on a preset distance tolerance, performing connected component labeling on the target three-dimensional model to obtain a plurality of sub-connected components of the target three-dimensional model; for each of the plurality of sub-connected components, constructing a length distribution sub-graph of the sub-connected component, and calculating a corresponding local screening threshold.

[0102] The preset distance tolerance is the maximum Euclidean distance allowed during connected component labeling, which is used to determine whether the end points of two line segments belong to the same sub-connected component. When the maximum Euclidean distance of the end points of two line segments is less than the preset distance tolerance, the screening module determines that the two line segments are connected and belong to the same sub-connected component.

[0103] In some embodiments, the preset distance tolerance can be set by those skilled in the art according to experience. For example, 0.1 m, 0.5 mm, 2 mm, etc.

[0104] Connected component labeling refers to a process of labeling mutually connected pixels or geometric elements in an image or geometric data as the same independent region.

[0105] Sub-connected component refers to a plurality of independent sub-regions obtained after connected component labeling.

[0106] In some embodiments, the screening module takes one contour line in the target three-dimensional model as an independent calculation unit in the connected component labeling algorithm, and performs connectedness analysis on the contour line based on the connected component labeling. Wherein, the determination of whether two calculation units are connected is based on whether the Euclidean distance between the two calculation units is less than or equal to a preset distance tolerance, if the Euclidean distance is less than or equal to the preset distance tolerance, it is determined to be connected, if the Euclidean distance is greater than the preset distance tolerance, it is determined to be not connected.

[0107] In some embodiments, the screening module adopts a connected component labeling method based on the spatial field when performing connected component labeling on the target three-dimensional model based on the preset distance tolerance, which specifically includes the following steps S1-S5.

[0108] Step S1, initialize data set and state. The screening module obtains the contour line set from the acquisition module, and sets an access state flag for each contour line in the contour line set. The access state flag is used to indicate whether the corresponding contour line has been classified into a certain connected component. The access state flag is initially defaulted to "False", and becomes "True" after being accessed.

[0109] Step S2, seed line segment selection. The screening module selects a contour line with a False access state from the contour line set as a seed line segment of the current connected component, and initializes a to-be-constructed sub-connected component based on the seed line segment, while marking the access state of the seed line segment as "True".

[0110] Step S3, tolerance neighborhood search. The screening module takes the seed line segment as the starting point and performs tolerance neighborhood search based on the spatial neighborhood relationship. The tolerance neighborhood search refers to calculating the Euclidean distance between the end points of the current seed line segment and the end points of the remaining unvisited line segments. When the Euclidean distance is less than or equal to the preset distance tolerance, it is determined that the corresponding line segments have a connected relationship, and the line segments that meet the connected condition are merged into the current sub-connected component, while the access state of the contour line merged into the current sub-connected component is marked as "True".

[0111] Step S4, sub-connected component generation. The screening module continues to perform tolerance neighborhood search on the line segments merged into the current sub-connected component until there is no line segment that meets the distance less than or equal to the preset distance tolerance, thereby completing the construction of a sub-connected component.

[0112] Step S5, global search. After completing the construction of the current sub-connected component, the screening module continues to select the next contour line that has not been accessed from the contour line set, and repeats the processing procedures of steps S2-S4 until all contour lines in the contour line set are classified, thereby obtaining multiple sub-connected components of the target three-dimensional model.

[0113] The length distribution subgraph is a histogram obtained by counting the lengths of all line segments in each sub-connected domain. The construction method of the length distribution subgraph is similar to that of the length distribution graph, and is not described here.

[0114] The local screening threshold refers to a reference value for distinguishing noise line segments and welds in each sub-connected domain.

[0115] The local screening threshold determination method is similar to the dynamic screening threshold determination method, and is not described here.

[0116] In some embodiments, for each sub-connected domain, the screening module calculates the local screening threshold corresponding to the sub-connected domain, then removes the contour lines in the sub-connected domain whose lengths are less than the local screening threshold, and retains the contour lines whose lengths are greater than or equal to the local screening threshold; then, the screening module collects the retained contour lines in each sub-connected domain to construct an initial line segment set.

[0117] In some embodiments of the present specification, by performing connected domain division on the target three-dimensional model, and independently constructing the length distribution subgraph and calculating the local screening threshold in each sub-connected domain, the problem of global dynamic screening threshold being not suitable for different scale components is avoided, the effective weld of small size components is prevented from being mistakenly removed by the plate thickness noise generated by large size components, and the accuracy and robustness of weld screening in complex models are improved.

[0118] In some embodiments, the first screening further includes: in response to the difference between the length of the contour line and the dynamic screening threshold being within a preset range, determining a closed geometric ring of the contour line based on the target three-dimensional model; obtaining the lengths of the remaining line segments in the closed geometric ring; and if the length of the contour line is the shortest line segment in the closed geometric ring, removing the contour line from the contour line set.

[0119] The preset range refers to the positive and negative deviation interval allowed between the length of the contour line and the dynamic screening threshold.

[0120] In some embodiments, the preset range can be set by a person skilled in the art based on experience.

[0121] In some embodiments, the preset range can be determined based on the length distribution graph.

[0122] In some embodiments, the preset range is negatively correlated with the distance between the plate thickness noise peak and the weld signal peak in the length distribution graph.

[0123] For example, when the distance between the plate thickness noise peak and the weld signal peak is large, it indicates that the noise line segment and the weld have a high degree of differentiation in length distribution, and a smaller preset range can be set at this time; when the distance between the plate thickness noise peak and the weld signal peak is small, it indicates that the noise line segment and the weld have a low degree of differentiation in length distribution, and a larger preset range needs to be set at this time, so that more contour lines with close length values enter the subsequent screening.

[0124] The distance between the plate thickness noise peak and the weld signal peak refers to the length difference of the contour lines corresponding to the plate thickness noise peak and the weld signal peak, that is, the difference of the abscissa corresponding to the plate thickness noise peak and the weld signal peak.

[0125] In some embodiments of the present specification, the preset range is dynamically adjusted through the length distribution diagram, which reasonably allocates computing resources while ensuring screening accuracy, and automatically enhances the checking strength for difficult scenarios with high data distribution overlap.

[0126] The closed geometric ring refers to a closed polygon loop formed by sequentially connecting the heads and tails of a plurality of contour lines.

[0127] In some embodiments, the screening module can start from the endpoints of the contour lines whose length difference with the dynamic screening threshold is within the preset range, and gradually track other contour lines connected to the endpoints based on the connection relationship of the line segments in the target three-dimensional model, until a closed loop is formed, thereby determining the closed geometric ring.

[0128] In some embodiments, the screening module can calculate the Euclidean distance between the two endpoints of each line segment in the closed geometric ring as the length of the line segment according to the coordinate values of the two endpoints in the three-dimensional coordinate system.

[0129] In some embodiments, in the structural design of H-shaped steel, the weld is used to realize the connection and reinforcement between components, and its length is usually greater than the plate thickness dimension of the component. If the weld is smaller than the length of the plate thickness line, the weld cannot provide effective structural reinforcement. Based on the above structural design principle, the screening module compares the length relationship of the contour lines in the closed geometric ring, and when a contour line is the shortest line segment in the closed geometric ring, the contour line is removed from the contour line set, thereby avoiding the misidentification of the plate thickness line of the component as a weld.

[0130] In some embodiments of the present specification, by introducing the line segment length comparison mechanism in the closed geometric ring, in the case where the contour line length is close to the dynamic screening threshold, further combined with the structural topological features for discrimination, the plate thickness line of the component is effectively avoided from being identified as a weld, and the accuracy and stability of the weld extraction result are improved.

[0131] Step 320, performing the following operations on each initial line segment in the initial line segment set.

[0132] In some embodiments, performing the following operations on each initial line segment in the initial line segment set includes performing steps 321 and 322 on each initial line segment in the initial line segment set. In some embodiments, steps 321 and 322 are performed by a screening module.

[0133] Step 321: Detect the intersection relationship between the initial line segment and the remaining initial line segments in the initial line segment set.

[0134] The initial line segment refers to the outline that is retained after the first screening.

[0135] Intersection relationship refers to the relative relationship between two line segments in space based on their geometric positions. In some embodiments, intersection relationship is used to characterize whether there is an intersection point between the line segments and the type of position of the intersection point.

[0136] In some embodiments, the intersection relationship includes parallelism, endpoint intersection, and interior point intersection. Parallelism means that the two line segments are oriented in the same or opposite directions in space and do not intersect in their extended directions. Interior point intersection means that the intersection point of the two line segments is located inside at least one of the line segments rather than at its endpoint. Endpoint intersection means that the intersection point of the two line segments is located at the endpoint of one of the line segments.

[0137] In some embodiments, the screening module can obtain the intersection relationship between each initial line segment based on the geometric properties (starting point coordinates, ending point coordinates, etc.) of each initial line segment in the target three-dimensional model.

[0138] For example, for any two initial line segments A and B, the screening module obtains the start and end coordinates of initial line segments A and B in the three-dimensional coordinate system, respectively, denoted as A(P1,P2) for initial line segment A and B(Q1,Q2) for initial line segment B. The two initial line segments are vectorized to obtain direction vectors u=P1-P2, v=Q1-Q2; based on the direction vectors u and v, a squared distance function is constructed for the two line segments. ,in, and Let these be the parameter variables to be solved. Then, by calculating partial derivatives or vector dot products, the solution is obtained. To reach the minimum parameter value and ; in the solution of parameter values and After limiting it to the range [0,1], if The parameter corresponding to the minimum The difference between 0 and 0 is less than a preset difference threshold, and the parameter If the points are within the range (0,1), then they are considered to be intersecting interior points; if The parameter corresponding to the minimum If the difference between the parameter and 0 is greater than a preset difference threshold, it is determined that the lines are parallel. the parameter corresponding to the minimum time is 0 or 1, and the parameter If the difference between the parameter and 0 is less than a preset difference threshold, it is determined that the lines intersect at an endpoint. The preset difference threshold is preset by a human.

[0139] Step 322, when the intersection relationship is an interior intersection, the initial line segment is divided into a plurality of sub-line segments based on the intersection point.

[0140] The sub-line segment refers to a line segment formed after the initial line segment is divided at the intersection point.

[0141] In some embodiments, the screening module divides the initial line segment in which the interior intersection occurs into two sub-line segments with the intersection point as the division point, where one sub-line segment is composed of the starting point of the initial line segment and the intersection point, and the other sub-line segment is composed of the intersection point and the end point of the initial line segment.

[0142] Step 330, based on the initial line segment set and the plurality of sub-line segments, a divided line segment set is constructed.

[0143] The divided line segment set refers to a line segment set composed of the initial line segments in the initial line segment set that are not divided, and the sub-line segments obtained by dividing the initial line segments in which the interior intersection occurs.

[0144] In some embodiments, the screening module directly retains the initial line segments in the initial line segment set that are not divided, and adds all the sub-line segments obtained by dividing based on the intersection points to form the divided line segment set.

[0145] Step 340, a second screening is performed on the divided line segment set to obtain a weld set.

[0146] The second screening refers to filtering the line segments in the divided line segment set to eliminate line segments that do not meet the length requirement.

[0147] In some embodiments, the screening object of the second screening is the divided line segment set.

[0148] For the definition of the weld set, see Figure 2 and related descriptions.

[0149] In some embodiments, the screening module eliminates the initial line segments in the divided line segment set that have a length less than a preset length threshold from the divided line segment set to obtain the weld set. For more information about the preset length threshold, see step 310 and related descriptions.

[0150] In some embodiments of the present specification, by detecting the intersection relationship of each initial line segment in the initial line segment set with the remaining initial line segments after the first screening, and splitting the initial line segment based on the intersection point when the intersection relationship is an interior point intersection, and then combining the sub-line segments obtained by splitting to construct a split line segment set and performing a second screening, the fine processing of the line segment topological relationship is realized. Thus, in the case of intersection between the long weld and the plate thickness line, by splitting the initial line segment based on the intersection relationship, the topological ambiguity introduced by the intersection position can be eliminated first, and then by the subsequent second screening, the line segments with a length less than the preset length threshold in the split line segment set are effectively removed, avoiding the weld being incorrectly cut or misidentified, thereby improving the purity and stability of the weld extraction result.

[0151] It should be noted that the above description of the process 200 and the process 300 is only for example and illustration, and does not limit the scope of the present specification. Those skilled in the art can make various modifications and changes to the process 200 and the process 300 under the guidance of the present specification. However, these modifications and changes are still within the scope of the present specification.

[0152] Figure 4 is an exemplary schematic diagram for determining the vertical welding parameter according to some embodiments of the present specification.

[0153] In some embodiments, for each of the plurality of vertical welds, in response to the presence of a plurality of horizontal welds with a determined direction in the plane where the vertical weld is located, the vertical welding parameter 420 is determined based on the topological association 410; in response to the absence of a plurality of horizontal welds with a determined direction in the plane where the vertical weld is located, a first detection region 430 and a second detection region 440 are constructed respectively with the two end points of the vertical weld as the center; based on the number of independent planes and the solid angle in the first detection region 430 and the second detection region 440, a first characteristic value 450 and a second characteristic value 460 are determined; and based on the first characteristic value 450 and the second characteristic value 460, the vertical welding parameter 420 is determined.

[0154] For more information on how to determine the vertical welding parameter based on the topological association when the plane where the vertical weld is located has a plurality of horizontal welds with a determined direction, see Figure 2 and the related description.

[0155] The first detection region refers to a spherical detection region constructed with a certain end point of the vertical weld as the center of the sphere and with a preset radius.

[0156] The second detection region refers to a spherical detection region constructed with the other end point of the vertical weld as the center of the sphere and with a preset radius.

[0157] In some embodiments, the preset radius is preset by those skilled in the art based on experience.

[0158] An independent plane refers to a planar surface region with a specific normal vector in a three-dimensional space, which is enclosed by a closed edge frame. The specific normal vector refers to a normal vector that is not parallel to the normal vectors of other planes.

[0159] The number of independent planes refers to the number of independent planes in the first detection region or the second detection region.

[0160] In some embodiments, the parameter determination module can obtain all the planes involved in the first detection region or the second detection region, and extract the normal vectors of the planes. For multiple planes with the same or opposite directions of the normal vectors, only one of the planes is retained and the remaining planes are discarded. The retained planes are counted to obtain the number of independent planes.

[0161] A solid angle refers to the projection area on a unit sphere, which is constructed with the spherical center of the detection region as the vertex, of the part in the detection region that is not blocked by other independent entities. In some embodiments, the larger the solid angle, the more open the space available for welding operations at the end point; the smaller the solid angle, the stronger the spatial constraint at the end point.

[0162] The first characteristic value refers to a numerical index representing the degree of spatial constraint of the first detection region corresponding to a certain vertical weld end point.

[0163] The second characteristic value refers to a numerical index representing the degree of spatial constraint of the second detection region corresponding to a certain vertical weld end point.

[0164] In some embodiments, the parameter determination module can normalize the number of independent planes and the solid angle in the first detection region corresponding to a certain vertical weld end point, and perform weighted summation on the normalized results according to a predetermined weight to obtain the first characteristic value corresponding to the certain vertical weld end point. The weight coefficient can be set according to experience to balance the influence of different spatial constraint factors on the characteristic value.

[0165] The determination method of the second characteristic value is the same as that of the first characteristic value, which is not described here.

[0166] In some embodiments, based on the first characteristic value and the second characteristic value, the parameter determination module can determine the vertical welding parameter in various ways. For example, the parameter determination module can determine the vertical weld end point corresponding to the larger value as the starting point of the vertical weld and the vertical weld end point corresponding to the smaller value as the end point of the vertical weld according to the relative size relationship between the first characteristic value and the second characteristic value. The parameter determination module determines the direction from the starting point of the vertical weld to the end point of the vertical weld as the scanning direction of the vertical welding parameter.

[0167] In some embodiments, in response to the difference between the first feature value and the second feature value being less than a preset difference threshold, a first air distance and a second air distance corresponding to the vertical weld joint are calculated, the first air distance corresponding to a first scanning direction, and the second air distance corresponding to a second scanning direction, the first scanning direction being different from the second scanning direction; and based on the first scanning direction, the second scanning direction, the first air distance and the second air distance, the vertical welding parameter is determined.

[0168] The preset difference threshold refers to a boundary value representing the difference between the first feature value and the second feature value. In some embodiments, the preset difference threshold can be set according to experience, or determined based on statistical analysis of historical welding data.

[0169] In some embodiments, when the difference between the first feature value and the second feature value is less than the preset difference threshold, it indicates that the degree of spatial constraint of the two end points of the vertical weld joint is close and difficult to distinguish.

[0170] The air distance refers to the path length of the welding equipment from the current position or the end point of the last weld joint to the start point of the target vertical weld joint without welding operation.

[0171] The first air distance refers to the air distance when the scanning direction of the vertical weld joint is the first scanning direction.

[0172] The second air distance refers to the air distance when the scanning direction of the vertical weld joint is the second scanning direction.

[0173] In some embodiments, the parameter determination module can obtain a neighboring weld joint with a determined welding direction closest to the spatial position of the vertical weld joint, and obtain the welding end point coordinates of the neighboring weld joint; and calculate the Euclidean distance between the neighboring welding end point coordinates and the corresponding start point coordinates of the vertical weld joint in the first scanning direction and the second scanning direction respectively, as the first air distance and the second air distance.

[0174] The first scanning direction refers to the direction along which one end point of the vertical weld joint points to the other end point of the vertical weld joint.

[0175] The second scanning direction refers to the direction opposite to the first scanning direction.

[0176] In some embodiments, the parameter determination module determines the scanning direction corresponding to the smaller air distance by comparing the first air distance and the second air distance, and takes the scanning direction as the scanning direction of the vertical weld joint, thereby determining the vertical welding parameter.

[0177] In some embodiments of this specification, when the difference between the first feature value and the second feature value is less than a preset difference threshold, the first idle distance and the second idle distance corresponding to the vertical weld in the first scanning direction and the second scanning direction are calculated respectively, and the scanning direction is selected based on the idle distance, so that the welding direction of the vertical weld is more reasonably connected with the path of the adjacent weld, thereby effectively shortening the movement path of the welding equipment in the non-welding state, reducing the invalid travel time, improving the continuity of welding path planning and the overall production efficiency of welding operation.

[0178] Figure 5 This is an exemplary schematic diagram illustrating the determination of flat welding parameters according to some embodiments of this specification.

[0179] In some embodiments, for each of the plurality of flat welds, a vertical vector corresponding to the flat weld is constructed, the vertical vector passing through the midpoint of the flat weld; the vertical vector is extended until the total length of the vertical vector exceeds a preset plate thickness; in response to the vertical vector not intersecting with the parallel boundary line of the independent entity to which the flat weld belongs, the scanning direction of the flat weld is maintained; in response to the vertical vector intersecting with the parallel boundary line of the independent entity to which the flat weld belongs, the scanning direction of the flat weld is changed.

[0180] A perpendicular vector is a vector located within the contact surface of a flat weld, originating from the midpoint of the flat weld and perpendicular to the weld.

[0181] The contact surface where the flat weld is located refers to the contact surface that includes the flat weld among the multiple contact surfaces of the independent entity to which the flat weld belongs and other independent entities.

[0182] Multiple contact surfaces between the independent entity to which the flat weld belongs and other independent entities can be obtained through the target 3D model.

[0183] In some embodiments, the direction of the vertical vector is the same as the scanning angle. For example, the scanning angle is to the left of the independent entity to which the flat weld belongs, and the vertical vector corresponding to the flat weld points to the left within the contact surface.

[0184] The preset plate thickness refers to the thickness of the independent entity to which the flat weld belongs. In some embodiments, the preset plate thickness can be set based on the structural parameters or empirical data of the target welded component.

[0185] The parallel boundary line of an independent entity refers to the outline line located within the contact surface of the flat weld and parallel to the flat weld.

[0186] In some embodiments, the parameter determination module can determine the independent entity to which the flat weld belongs based on the target three-dimensional model, extract the contact surface between the independent entity and other independent entities, and screen out the contour lines parallel to the direction of the flat weld in the contact surface as the parallel boundary lines of the independent entity to which the flat weld belongs, for subsequent detection of the intersection relationship with the perpendicular vector.

[0187] In some embodiments, the parameter determination module can determine whether the current scanning angle points towards the interior of an independent entity by detecting whether the perpendicular vector intersects with the parallel boundary line. If the perpendicular vector intersects with the parallel boundary line of the independent entity to which the flat weld belongs, it indicates that the current scanning angle points towards the interior of the independent entity. Welding equipment performing welding from this scanning angle may collide with the steel plate, therefore the scanning direction of the flat weld needs to be changed. If the perpendicular vector does not intersect with the parallel boundary line of the independent entity to which the flat weld belongs, it indicates that the current scanning angle does not point towards the interior of the independent entity, and there is no need to change the scanning direction of the flat weld.

[0188] In some embodiments, changing the scanning direction of the flat weld seam involves exchanging the start and end points of the flat weld seam, thereby causing the welding equipment to scan the flat weld seam in a direction opposite to the original scanning direction. Since the welding equipment maintains a fixed direction of movement (e.g., from left to right) in the weld seam scanning direction, once the scanning direction is determined, the corresponding scanning angle (i.e., the direction of the perpendicular vector) is also determined. When the perpendicular vector of the flat weld seam intersects the parallel boundary line of the independent entity to which the flat weld seam belongs in the current scanning direction, it indicates that the welding equipment, at that scanning angle, will pass through the independent entity from the side excluding the flat weld seam and perform welding on the other side of the independent entity, posing a risk of collision, which does not conform to actual welding conditions. Therefore, the scanning direction is changed by exchanging the start and end points of the flat weld seam. After the scanning direction is changed, while the welding equipment maintains the same fixed direction of movement, the scanning angle corresponding to the flat weld seam is flipped relative to the independent entity, causing the perpendicular vector to point outwards from the flat weld seam and no longer intersect the parallel boundary line, thus achieving safe welding.

[0189] In some embodiments of this specification, by constructing a perpendicular vector at the midpoint of the flat weld and detecting its intersection with the parallel boundary line of the independent entity to which it belongs, the scanning direction of the flat weld can be automatically corrected based on the geometric position relationship. This avoids the welding equipment scanning in a direction pointing into the interior of the independent entity, thereby ensuring that the welding equipment has a reasonable spatial orientation when performing flat weld welding, reducing the risk of interference or collision, and improving the stability and reliability of the welding operation.

[0190] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0191] Also, the use of "a" or "an" or "the" or "at least one" or "one or more" or "one or more instances" throughout the specification try to convey a similar meaning as the term "one or more" unless the context clearly dictates otherwise. The terms "comprising," "including," "containing," and "having" are intended to be open-ended terms. Likewise, the term "comprises" is synonymous with "includes" or "contains" for purposes of the specification and claims. Therefore, use of these terms is not intended to limit the scope of the disclosure to the specific embodiments discussed. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish one element from another, and do not require that the elements be in any particular order. It is also noted that various implementations of the disclosure have been described as comprising, including, containing, comprising, having or any other comparable term. However, the term "comprising" is used herein to mean the open-ended term "including but not limited to," and thus should be interpreted to cover the terms "consisting of" and "consisting essentially of" and their grammatical equivalents. In other words, the phrase "comprising" should be interpreted as including the more restrictive phrases "consisting of" and "consisting essentially of."

[0192] Furthermore, the order of presentation of the processes and methods of aspects of the present disclosure is not limited to the order in which those processes and methods are recited in the specification unless a strict order is otherwise specified. Although the above disclosure discusses some presently preferred embodiments of the application, it is to be understood that the application is not limited to the above-disclosed embodiments, but is instead defined only by the claims hereinafter presented. For example, although the system components described above can be implemented by hardware devices, they can also be implemented by software solutions only, such as installing the described system on an existing server or mobile device.

[0193] Similarly, it is noted that the foregoing description of embodiments of the present disclosure is intended to be merely exemplary of the various ways in which aspects of the present disclosure can be implemented and that numerous other arrangements of processes or methods embodied in the present disclosure are possible. Therefore, although the present disclosure has been described in some detail with respect to certain embodiments, one skilled in the art should not consider the above description to be limiting in any way. Indeed, various modifications of the application, in addition to those described, will be apparent to one of ordinary skill in the art upon reading the foregoing description. For example, although the system components described above can be implemented by hardware devices, they can also be implemented by software solutions only, such as installing the described system on an existing server or mobile device.

[0194] Some embodiments use numerical terms to describe amounts of ingredients, properties, and the like. Unless otherwise specified, "about," "approximately," or "substantially" preceding a numerical term means that the term can vary from the recited value by ±20%. Accordingly, numerical parameters in the specification and claims are approximations, and vary depending upon the desired properties sought to be obtained by the particular embodiment. In some embodiments, numerical parameters are approximations that can vary from the stated value by a reasonable amount. In some embodiments, numerical parameters are determined by the particular operational constraints of the systems and devices being described. In some embodiments, numerical parameters are approximations that can vary from the stated value by a reasonable amount. In some embodiments, numerical parameters are determined by the particular operational constraints of the systems and devices being described.

[0195] Each patent, patent application, patent publication, and other material cited in this specification is hereby incorporated by reference in its entirety herein for the teachings relevant to the sentence and / or paragraph in which the reference is presented. Document histories, to the extent not inconsistent with the pertinent U.S. patent application file history, are also incorporated by reference herein. To the extent that material incorporated by reference contradicts or contradicts any portion of this specification, including definition, the portion of the material incorporated by reference prevails. Note, however, that in the event of inconsistencies between any such material and the present specification, including definitions, the present specification, including definitions, will control.

[0196] Finally, it should be understood that the embodiments described herein are merely exemplary of the principles of the present disclosure. Other embodiments can be devised without departing from the scope of the present disclosure. Accordingly, the embodiments described herein are not intended to limit the scope of the present disclosure. Rather, the scope of the present disclosure is to be determined by the claims which follow.

Claims

1. A weld extraction method based on three-dimensional geometric feature analysis, comprising: Obtain the target 3D model, and obtain the contour line set based on the geometric Boolean intersection of each independent entity in the target 3D model; A screening process is performed on the contour line set to obtain a weld set. The screening process includes a first screening, a segmentation process, and a second screening, wherein the screening objects corresponding to the first screening and the second screening are different. Based on the coordinate difference of each weld in the weld set in a preset direction, multiple vertical welds and multiple horizontal welds are determined. Determine the flat welding parameters for the plurality of flat welds; The vertical welding parameters are determined based on the flat welding parameters, the plurality of vertical welds, and the topological association of the plurality of flat welds.

2. The method according to claim 1, characterized in that, The step of performing a screening process on the contour set to obtain the weld set includes: The first filtering is performed on the set of contour lines to obtain an initial set of line segments; Perform the following operations on each initial line segment in the initial line segment set: Detect the intersection relationship between the initial line segment and the remaining initial line segments in the set of initial line segments; When the intersection relationship is an interior point intersection, the initial line segment is divided into multiple sub-line segments based on the intersection points; Based on the initial set of line segments and the multiple sub-line segments, construct a set of segmented line segments; The second filtering is performed on the set of segmented lines to obtain the set of welds.

3. The method according to claim 2, characterized in that, The first screening includes: Calculate the lengths of all contour lines in the contour line set and construct a length distribution map; Based on the plate thickness noise peak and weld signal peak in the length distribution map, a dynamic screening threshold is determined. The initial line segment set is obtained by removing the contour lines whose length is less than the dynamic filtering threshold from the contour line set.

4. The method according to claim 1, characterized in that, Determining the flat welding parameters of the plurality of flat welds includes: For each of the plurality of flat welds Construct a perpendicular vector corresponding to the flat weld, the perpendicular vector passing through the midpoint of the flat weld; The total length extending from the perpendicular vector to the perpendicular vector exceeds the preset plate thickness; In response to the fact that the vertical vector does not intersect the parallel boundary line of the independent entity to which the flat weld belongs, the scanning direction of the flat weld is maintained; In response to the intersection of the vertical vector with the parallel boundary line of the independent entity to which the flat weld belongs, the scanning direction of the flat weld is reversed.

5. A weld seam extraction system based on three-dimensional geometric feature analysis, characterized in that, include: The acquisition module is configured as follows: Obtain the target 3D model, and obtain the contour line set based on the geometric Boolean intersection of each independent entity in the target 3D model; The screening module is configured as follows: A screening process is performed on the contour line set to obtain a weld set. The screening process includes a first screening, a segmentation process, and a second screening, wherein the screening objects corresponding to the first screening and the second screening are different. The parameter determination module is configured as follows: Based on the coordinate difference of each weld in the weld set in a preset direction, multiple vertical welds and multiple horizontal welds are determined. Determine the flat welding parameters for the plurality of flat welds; Based on the flat welding parameters, the topological association between the plurality of vertical welds and the plurality of flat welds, the vertical welding parameters are determined.

6. The system according to claim 5, characterized in that, The screening module is further configured to: The first filtering is performed on the set of contour lines to obtain an initial set of line segments; Perform the following operations on each initial line segment in the initial line segment set: Detect the intersection relationship between the initial line segment and the remaining initial line segments in the set of initial line segments; When the intersection relationship is an interior point intersection, the initial line segment is divided into multiple sub-line segments based on the intersection points; Based on the initial set of line segments and the multiple sub-line segments, construct a set of segmented line segments; The second filtering is performed on the set of segmented lines to obtain the set of welds.

7. The system according to claim 6, characterized in that, The screening module is further configured to: Calculate the lengths of all contour lines in the contour line set and construct a length distribution map; Based on the plate thickness noise peak and weld signal peak in the length distribution map, a dynamic screening threshold is determined. The initial line segment set is obtained by removing the contour lines whose length is less than the dynamic filtering threshold from the contour line set.

8. The system according to claim 5, characterized in that, The parameter determination module is further configured to: For each of the plurality of flat welds Construct a perpendicular vector corresponding to the flat weld, the perpendicular vector passing through the midpoint of the flat weld; The total length extending from the perpendicular vector to the perpendicular vector exceeds the preset plate thickness; In response to the fact that the vertical vector does not intersect the parallel boundary line of the independent entity to which the flat weld belongs, the scanning direction of the flat weld is maintained; In response to the intersection of the vertical vector with the parallel boundary line of the independent entity to which the flat weld belongs, the scanning direction of the flat weld is reversed.

9. A weld extraction device based on three-dimensional geometric feature analysis, comprising a processor, the processor being used to execute the weld extraction method based on three-dimensional geometric feature analysis according to any one of claims 1 to 4.

10. A computer-readable storage medium storing computer instructions, wherein when a computer reads the computer instructions in the storage medium, the computer executes the weld extraction method based on three-dimensional geometric feature analysis as described in any one of claims 1 to 4.

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