CN113205594B - STL-based bent pipe model skeleton extraction method and system - Google Patents
STL-based bent pipe model skeleton extraction method and system Download PDFInfo
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- G06F2113/10—Additive manufacturing, e.g. 3D printing
Abstract
The invention discloses an STL-based bent pipe model skeleton extraction method and an extraction system thereof. The bent pipe type model skeleton extraction method comprises the following steps: s1, reading an STL file of the three-dimensional model of the bent pipe product; s2 adding the associated information of the triangular patch in the three-dimensional model; s3, determining a printing starting plane and a printing ending plane of the three-dimensional model; s4 searching a bone point fitting point in the three-dimensional model; s5, projecting the bone point fitting points on the plane to obtain fitting bone points; s6, interpolating the fitted skeleton points to obtain a model skeleton. According to the method, based on the characteristic that the section points in the bent pipe model are approximately in the same plane, the model skeleton is obtained by extracting the points of each layer which are approximately in the same plane to fit the skeleton points, a new skeleton extraction thought is provided, the non-lofting and simple lofting bent pipe models can be processed, the time consumption of an algorithm during processing is short, the speed is high, the model skeleton can be extracted quickly and efficiently, and reliable bases are provided for the subsequent slicing division of the unsupported 3D printing.
Description
Technical Field
The invention relates to the technical field of unsupported 3D printing, in particular to an STL-based bent pipe model skeleton extraction method, an extraction system adopting the model skeleton extraction method and a computer terminal for realizing the model skeleton extraction method.
Background
3D printing is an additive manufacturing technology, which is based on a digital model file, a computer is used for cutting a model into a series of sheets with thickness, each layer of sheet is manufactured by a 3D printing device from bottom to top, and finally, the sheets are stacked to obtain a molded three-dimensional entity.
Traditional 3D prints and prints for the triaxial, and the model carries out the layering cutting and prints and piles up along the Z axle direction, when there is unsettled structure in the model, needs to print bearing structure help material and piles up. Not only is the support structure wasteful of material, affecting the quality of the mould surface, but the support structure is difficult to remove in parts of the mould such as bends. To solve this problem, unsupported 3D printing techniques have started to emerge in recent years. Whether the five-axis type unsupported 3D printing or the mechanical arm type unsupported 3D printing is adopted, the slicing plane is required to be determined, the model can be reasonably cut in a layered mode, and when the slicing plane is obtained, a model framework is usually required to be extracted.
The existing three-dimensional model skeleton extraction technology is many and roughly divided into four types: based on topological and geometric analysis, topological refinement, distance transformation and generalized potential field. In unsupported 3D printing, not only the extracted skeleton is required to accurately reflect the topological structure of the model, but also the operation speed is high so as to meet the production requirement. And the lower skeleton extraction method cannot rapidly extract the model skeleton, so that a reliable basis cannot be provided for the division of the subsequent slices printed by the unsupported 3D printer.
Disclosure of Invention
The invention provides the STL-based bent pipe model skeleton extraction method and the STL-based bent pipe model skeleton extraction system, which are used for accurately and quickly extracting a bent pipe model skeleton and providing reliable basis for the division of the unsupported 3D printed subsequent section.
The invention is realized by adopting the following technical scheme: an STL-based elbow model skeleton extraction method comprises the following steps:
s1, reading an STL file of the three-dimensional model of the bent pipe product;
s2 adding the associated information of the triangular patch in the three-dimensional model;
s3, determining a printing starting plane and a printing ending plane of the three-dimensional model;
s4 searching a bone point fitting point in the three-dimensional model;
the search method of the bone point fitting points is used for searching the bone point fitting points, and the search method comprises the following steps:
s41, using the point on the initial plane as the front layer point set, determining the searching direction;
s42 searching the nearest neighbor point of the previous layer point set and marking as the current layer point set;
the marking method of the current-layer point set is used for processing the nearest neighbor point of the previous-layer point set, and the marking method comprises the following steps:
s421 selecting any one point in the previous layer point set as an old father point A;
s422, searching the neighbor point of the old father point A as an old child point B;
s423, taking the rest points as undetermined points C in the triangle where the old father point A and the old child point B are located;
s424, judging whether the undetermined point C exists in the current layer fitting point set;
if yes, go to S425; otherwise, go to S426;
s425, when the layer searching is finished;
s426, judging whether the undetermined point C belongs to a front layer point set;
if yes, go to S427; otherwise, go to S428;
s427, the undetermined point C is confirmed as a new father point a, and father point information in the membership relation that the point a is the father point of the old child point B is recorded;
determining to obtain a new triangle according to the associated information of the edge formed by the new father point a and the old child point B and the edge of the old triangle, and then setting the serial number of the new father point a in the new triangle as the old father point A n Returning to S422;
s428, putting the undetermined point C into the current layer fitting point set to serve as a new sub-point b;
according to the old father point A, the newDetermining the associated information of the edge formed by the sub-point B and the old triangle edge to obtain a new triangle, and then determining the serial number of the new sub-point B in the new triangle as the old sub-point B n Returning to S423;
s43, extracting points which are approximately on a plane in the current-layer point set, and marking the points as the current-layer fitting point set;
the marking method of the current-layer fitting point set is used for processing points which are approximately on a plane in the current-layer point set, and the marking method comprises the following steps:
s431 sets a distance threshold value threshold1 and a number threshold value threshold 2;
s432 randomly selecting three points from the current layer point set to form a plane;
s433, confirming whether the distance from the layer point to the plane is less than threshold1 when the layer point is collected and the distance from the layer point to the plane exceeds threshold 2;
if yes, go to S434; if not, returning to S432;
s434 marks the points as points approximately on the plane;
s44 deleting the unselected points in the current layer point set, inquiring and adding the recorded father point information to obtain a new point set, and taking the new point set as a previous layer point set;
s45, judging whether the search of the bone point fitting point touches the termination plane;
if yes, go to S46; otherwise, return to S42;
s46, the operation of searching the bone point fitting point is finished;
s5, projecting the bone point fitting points on the plane to obtain fitting bone points;
s6, interpolating the fitted skeleton points to obtain a model skeleton.
As a further improvement of the above scheme, the start plane and the end plane are determined by artificial selection;
and/or the starting plane selects a circular section of the three-dimensional model, and the ending plane selects a square section of the three-dimensional model.
As a further improvement of the above solution, the search direction adopts a direction in which the start plane points to the end plane; and searching according to the searching direction and the associated information to obtain the old child point B.
As a further improvement of the scheme, after the undetermined point C is confirmed as a new father point a, the old father point A is discarded;
or, after the undetermined point C is taken as a new sub-point B, the old sub-point B is discarded.
As a further improvement of the above solution, A n 、B n And when the new triangle is determined for the nth time, respectively selecting the sequence numbers of the old father point and the old child point in the new triangle.
As a further improvement of the above solution, the method for finding the fitted bone points by plane projection fitting points is used for processing the bone point fitting points, and the method for finding the fitted bone points is as follows:
s51, performing two-dimensional projection on the in-situ fitting three-dimensional point set by using a coordinate transformation matrix to obtain a two-dimensional point set;
s52, calculating the centroid of the polygon formed by the two-dimensional point set;
s53, converting the centroid coordinate back to the original coordinate system, and taking the point as a skeleton point;
s54, whether a next layer of fitting three-dimensional point set exists or not;
otherwise, exit from S5; if yes, the process returns to S51.
Further, the centroid of the polygon is calculated as
The polygon is divided into a plurality of small triangles; in the formula P i Is the centroid coordinate of the ith small triangle, S i Is an area.
A model skeleton extraction system, the extraction system comprising:
the STL file reading module is used for reading an STL format file of the three-dimensional model of the product;
the association information adding module is used for adding the adjacency information of each triangular patch in the three-dimensional model; the triangle patch comprises all triangles sharing the target triangle edge and the vertex;
the bone point fitting point searching module is used for searching the bone point fitting points;
a bone point fitting point processing module for processing the bone point fitting points to obtain fitted bone points; and
and the one-dimensional Hermite interpolation processing module is used for interpolating the fitted bone points according to the distance between the bone points.
As a further improvement of the scheme, the model skeleton extraction system adopts the STL-based bent pipe model skeleton extraction method.
A computer terminal comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the STL-based bent-tube model skeleton extraction method when executing the program.
The STL-based bent pipe model skeleton extraction method and the extraction system thereof have the following beneficial effects: the novel framework extraction thought is provided, the characteristic that section points in an STL-based bent pipe model are approximately in the same plane is adopted, and the skeleton points are fitted by extracting points of each layer of the approximately same plane, so that a model framework is obtained.
Drawings
FIG. 1 is a flow chart of the steps of the present invention.
FIG. 2 is a diagram of an exemplary model of a 90 lofted elbow with a transition from a round cross-section to a square cross-section according to the present invention.
Fig. 3 is a flowchart of a method of searching for a skeletal point fitting point according to the present invention.
FIG. 4 is an exemplary diagram of a current layer point set labeled as a nearest neighbor point set searched from a previous layer point set according to a search direction.
FIG. 5 is a flowchart of a method for marking current-level point sets according to the present invention.
Fig. 6 is an exemplary diagram of a point C to be detected which is not in the previous layer point set and is determined as a new sub-point b in a certain searching process according to the present invention.
FIG. 7 is an exemplary diagram of finding a point set approximately in the same plane from a current layer point set as a fitting point set.
FIG. 8 is a flowchart of a method for labeling a current-level fitting point set according to the present invention.
FIG. 9 is a flow chart of a method for plane projection of fitted points to find fitted bone points in accordance with the present invention.
FIG. 10 is an exemplary diagram of fitting bone points using fitted point composition polygon centroids.
FIG. 11 is a model skeleton diagram obtained by interpolation of fitted skeleton points according to the present invention.
Fig. 12 is a block diagram of a model skeleton extraction system in embodiment 2 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In order to accurately and quickly extract the bent pipe model skeleton and provide a reliable basis for the division of subsequent slices for unsupported 3D printing, the inventor provides the following embodiments.
Example 1
Referring to fig. 1, the embodiment discloses an STL-based method for extracting a bent pipe model skeleton, which includes the following steps:
s1, reading an STL file of the three-dimensional model of the bent pipe product by using matlab software;
STL files simply represent three-dimensional CAD models of items with a triangular mesh: the bent pipe in the STL file is an entity formed by connecting countless closed contours perpendicular to a model neutral curve;
referring to fig. 2, fig. 2 is a schematic diagram of an exemplary 90 ° lofted elbow with a transition from a circular cross-section to a square cross-section.
S2 adding the associated information of the triangular patch in the three-dimensional model;
the associated information refers to the adjacent information of each triangular patch; the triangle patch comprises all triangles sharing the target triangle edge and the vertex;
the adjacent information can be obtained by inquiring the serial number of the point with the same coordinate as the point, and the associated information can be obtained by searching the intersection of the adjacent information of the point in the two points forming the edge.
S3, determining a printing starting plane and a printing ending plane of the three-dimensional model;
the printing starting plane and the printing ending plane of the three-dimensional model are determined by artificial selection. In this embodiment, a description will be given by taking, as an example, a case where a circular cross section of the model is selected as a printing start plane and a square cross section of the model is selected as a printing end plane.
S4 searching a bone point fitting point in the three-dimensional model;
with continuing reference to fig. 3, fig. 3 is a flow chart of a method for searching for bone point fitting points, which is used to search for bone point fitting points, as follows.
S41, taking the point on the initial plane as a front-layer point set and determining the searching direction;
the search direction is the direction from the starting plane to the ending plane, and this embodiment describes the direction from the circular cross section to the square cross section in the model as the search direction.
S42 searching the nearest neighbor point of the previous layer point set and marking as the current layer point set;
referring to fig. 4, fig. 4 is a diagram showing an exemplary view of a current layer point set, which is a nearest neighbor point set searched by a previous layer point set according to a search direction. The coordinate axes in the figure represent three-dimensional space distances, and the thin points are model point clouds (the lines of the model are omitted for convenient observation of the point clouds).
Referring to fig. 5, fig. 5 is a flowchart illustrating a method for marking a current-layer point set, which is used to process nearest neighbors of a previous-layer point set.
S421 selecting any one point in the previous layer point set as an old father point A;
s422, searching the neighbor point of the old father point A as an old child point B;
s423, taking the rest points as undetermined points C in the triangle where the old father point A and the old child point B are located;
s424, judging whether the undetermined point C exists in the current layer fitting point set;
if yes, go to S425; otherwise, go to S426;
s425, when the layer searching is finished;
s426, judging whether the undetermined point C belongs to a front layer point set;
if yes, go to S427; otherwise, go to S428;
s427, the undetermined point C is confirmed as a new father point a (after the undetermined point C is confirmed as the new father point a, the old father point A is omitted), and father point information in the membership relation that the point a is the father point of the old child point B is recorded;
determining to obtain a new triangle according to the associated information of the edge formed by the new father point a and the old child point B and the edge of the old triangle, and then setting the serial number of the new father point a in the new triangle as the old father point A n Then, the process jumps to S422, and S422 to S428 are repeatedly executed.
S428, putting the undetermined point C into the current layer fitting point set to serve as a new sub-point B (after the undetermined point C serves as the new sub-point B, an old sub-point B is omitted);
determining to obtain a new triangle according to the associated information of the edge formed by the old father point A and the new child point B and the edge of the old triangle, and then determining the serial number of the new child point B in the new triangle as the old child point B n And returns to S423.
Wherein, A n 、B n And when the new triangle is determined for the nth time, respectively selecting the sequence numbers of the old father point and the old child point in the new triangle.
Referring to fig. 6 again, fig. 6 is a diagram showing an example in which a to-be-detected point C (new point) is not in a previous layer point set and is determined as a new sub-point b in a certain search process, where the example is a two-dimensional observation angle, and a coordinate axis represents a two-dimensional plane distance.
S43, extracting points which are approximately on a plane in the current-layer point set, and marking the points as the current-layer fitting point set;
with continuing reference to fig. 7, fig. 7 is a diagram illustrating an example of finding a point set approximately in the same plane from a current layer point set as a fitting point set, where the example is a two-dimensional observation angle and the coordinate axis represents a two-dimensional plane distance.
Continuing to refer to fig. 8, fig. 8 is a flowchart of a labeling method for a current layer fitting point set, which is used for processing points in the current layer point set approximately on a plane, and the labeling method for the current layer fitting point set is as follows.
S431 sets a distance threshold1, a number threshold 2.
S432 randomly selects three points from the current layer point set to form a plane.
S433, confirming whether the distance from the layer point to the plane is less than threshold1 when the layer point is collected and the distance from the layer point to the plane exceeds threshold 2;
if yes, go to S434; if not, returning to S432;
s434 marks the points as points approximately on the plane. The circled points in fig. 7 are the approximately coplanar points marked by the selected layer.
S44 deleting the unselected points in the current layer point set, inquiring and adding the recorded father point information to obtain a new point set, and taking the new point set as the previous layer point set. A point not circled in fig. 7 will perform S44.
S45, judging whether the search of the bone point fitting point touches the termination plane;
if yes, go to S46; otherwise, return to S42;
and finally selecting points in circles in the graph as bone fitting points of the layer through plane searching and threshold judgment.
S46 ends the operation of searching for the bone point fitting point.
S5, projecting the bone point fitting points on the plane, and solving the fitting bone points;
referring to fig. 9, fig. 9 is a flowchart illustrating a method for calculating a fitting bone point by plane projection fitting points, which is used for processing the bone point fitting points and calculating the fitting bone point as follows.
S51, performing two-dimensional projection on the in-situ fitting three-dimensional point set by using the coordinate transformation matrix to obtain a two-dimensional point set.
S52, calculating the centroid of the polygon formed by the two-dimensional point set;
the centroid calculation formula of the polygon is
Wherein the polygon is divided into several small triangles, P in the formula i Is the centroid coordinate of the ith small triangle, S i Is an area.
S53, converting the centroid coordinate back to the original coordinate system, and taking the point as a skeleton point;
referring to fig. 10, fig. 10 is a diagram illustrating an exemplary process of fitting a bone point to a centroid of a polygon composed of fitting points, which is a final result obtained after the processes of S51 to S53. In fig. 10, the coordinate axes represent three-dimensional spatial distances, and the skeleton points shown in the figure are centroids of planar polygons formed by sequentially connecting the fitting points.
S54, whether a next layer of fitting three-dimensional point set exists or not;
otherwise, exit from S5; if so, the process returns to S51 (until all the fitted three-dimensional point sets are processed).
S6, interpolating the fitted skeleton points to obtain a model skeleton;
and performing one-dimensional Hermite interpolation according to the distance between the skeleton points to finally obtain the model skeleton.
Referring to fig. 11, fig. 11 is an exemplary diagram of a model skeleton finally obtained by interpolation of fitted bone points, in which coordinate axes represent three-dimensional spatial distances, and black bold lines in the model shown in the diagram are used for Hermite interpolation of the fitted bone points to obtain the model skeleton.
When models such as bent tubes are processed, the characteristic that section points in the bent tube models based on the STL are approximately on the same plane is utilized, and extracted points of each layer which are approximately on the same plane are adopted to fit skeleton points, so that the model skeleton is obtained. The framework extraction thought can process non-lofting and simple lofting elbow models, is good in robustness when the models are processed, the processing time on matlab is about 4.1s, the algorithm is short in time consumption and fast in speed, the model frameworks can be extracted quickly and efficiently, the extracted frameworks are basically consistent with the mathematical theoretical central line or the artificial observation central line of the models, and reliable basis can be provided for the division of the unsupported 3D printed follow-up slices.
Example 2
Referring to fig. 12, the STL-based model skeleton extraction method according to embodiment 1 may be designed as an application software, such as the model skeleton extraction system provided in this embodiment, which is loaded into a required electronic device to implement the corresponding model skeleton extraction method. A model skeleton extraction system comprises an STL file reading module, an associated information adding module, a skeleton point fitting point searching module, a skeleton point fitting point processing module and a one-dimensional Hermite interpolation processing module.
And the STL file reading module is used for reading the STL format file of the three-dimensional model of the product. The association information adding module is used for adding the adjacency information of each triangular patch in the three-dimensional model; wherein a triangle patch contains all triangles that share the target triangle edge and vertex. The bone point fitting point searching module is used for searching the bone point fitting points. The bone point fitting point processing module is used for processing the bone point fitting points to obtain fitting bone points. And the one-dimensional Hermite interpolation processing module interpolates the fitted bone points according to the distance between the bone points to obtain a model skeleton.
The model skeleton extraction system, when executed, implements the steps of the STL-based bent-tube model skeleton extraction method as described in embodiment 1, and therefore, the model skeleton extraction system will not be described in detail in this embodiment.
Example 3
The present embodiment provides a computer terminal, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the steps of the STL-based bent-tube model skeleton extraction method according to embodiment 1.
When the model skeleton extraction method is applied, the model skeleton extraction method can be applied in a software form, for example, the model skeleton extraction method is designed into an independently running program and is installed on a computer terminal, in other embodiments, the model skeleton extraction method can also be designed into an embedded running program and is installed on the computer terminal, and the computer terminal can adopt a computer and can also adopt other intelligent equipment.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (9)
1. The STL-based bent pipe model skeleton extraction method is characterized by comprising the following steps of:
s1, reading an STL file of the three-dimensional model of the bent pipe product;
s2 adding the associated information of the triangular patch in the three-dimensional model;
s3, determining a printing starting plane and a printing ending plane of the three-dimensional model;
s4 searching a bone point fitting point in the three-dimensional model;
the search method of the bone point fitting points is used for searching the bone point fitting points, and the search method comprises the following steps:
s41, using the point on the initial plane as the front layer point set, determining the searching direction;
s42 searching the nearest neighbor point of the previous layer point set and marking as the current layer point set;
the marking method of the current-layer point set is used for processing the nearest neighbor point of the previous-layer point set, and the marking method of the current-layer point set is as follows:
s421 selecting any one point in the previous layer point set as an old father point A;
s422, searching the neighbor point of the old father point A as an old child point B;
s423, taking the rest points as undetermined points C in the triangle where the old father point A and the old child point B are located;
s424, judging whether the undetermined point C exists in the current layer fitting point set;
if yes, go to S425; otherwise, go to S426;
s425, when the layer searching is finished;
s426, judging whether the undetermined point C belongs to a front layer point set;
if yes, go to S427; if not, go to S428;
s427, the undetermined point C is confirmed as a new father point a, and father point information in the membership relation that the point a is the father point of the old child point B is recorded;
determining to obtain a new triangle according to the associated information of the edge formed by the new father point a and the old child point B and the edge of the old triangle, and then setting the serial number of the new father point a in the new triangle as the old father point A n Returning to S422;
s428, putting the undetermined point C into the current layer fitting point set to serve as a new sub-point b;
determining to obtain a new triangle according to the association information of the edge formed by the old father point A and the new child point B and the old triangle edge, and then determining the serial number of the new child point B in the new triangle as the old child point B n Returning to S423;
s43, extracting points which are approximately on a plane in the current-layer point set, and marking the points as the current-layer fitting point set;
the method for marking the current-layer fitting point set is used for processing points which are approximately on a plane in the current-layer point set, and the method for marking the current-layer fitting point set comprises the following steps:
s431 sets a distance threshold value threshold1 and a number threshold value threshold 2;
s432 randomly selecting three points from the current layer point set to form a plane;
s433, confirming whether the distance from the layer point to the plane is less than threshold1 when the layer point is collected and the distance from the layer point to the plane exceeds threshold 2;
if yes, go to S434; if not, returning to S432;
s434 marks the points as points approximately on the plane;
s44 deleting the unselected points in the current layer point set, inquiring and adding the recorded father point information to obtain a new point set, and taking the new point set as a previous layer point set;
s45, judging whether the search of the bone point fitting point touches the termination plane;
if yes, go to S46; otherwise, return to S42;
s46, the operation of searching the bone point fitting point is finished;
s5, projecting the bone point fitting points on the plane to obtain fitting bone points;
s6, interpolating the fitted skeleton points to obtain a model skeleton.
2. The STL-based method for extracting the frameworks of bent tubes models as claimed in claim 1, wherein the start plane and the end plane are determined by artificial selection;
and/or the starting plane selects a circular section of the three-dimensional model, and the ending plane selects a square section of the three-dimensional model.
3. The STL-based framework extraction method for bent pipes according to claim 1, wherein the search direction is a direction in which a start plane points to an end plane; and searching according to the searching direction and the associated information to obtain the old child point B.
4. The STL-based skeleton extraction method for bent pipes of claim 1, wherein the undetermined point C is determined as a new parent point a, and then the old parent point A is discarded;
or, after the undetermined point C is taken as a new sub-point B, the old sub-point B is discarded.
5. The STL-based method for extracting skeleton of bent pipe model according to claim 1, wherein A is n 、B n And when the new triangle is determined for the nth time, respectively selecting the sequence numbers of the old father point and the old child point in the new triangle.
6. An STL-based framework extraction method for an elbow model according to claim 1, wherein the plane projection fitting points to find fitting bone points are used for processing the bone point fitting points, and the method for finding fitting bone points is as follows:
s51, performing two-dimensional projection on the in-situ fitting three-dimensional point set by using a coordinate transformation matrix to obtain a two-dimensional point set;
s52, calculating the centroid of the polygon formed by the two-dimensional point set;
s53, converting the centroid coordinate back to the original coordinate system, and taking the point as a skeleton point;
s54, whether a next layer of fitting three-dimensional point set exists or not;
otherwise, exit from S5; if yes, the process returns to S51.
7. The STL-based method for extracting skeleton of bent pipe model according to claim 6, wherein the centroid of the polygon is calculated as
The polygon is divided into a plurality of small triangles; in said formula P i Is the ith small triangle centroid coordinate, S i Is an area.
8. A model skeleton extraction system using the STL-based bent-tube model skeleton extraction method according to any one of claims 1 to 7, the extraction system comprising:
the STL file reading module is used for reading an STL format file of the three-dimensional model of the product;
the association information adding module is used for adding the adjacency information of each triangular patch in the three-dimensional model; the triangle patch comprises all triangles sharing the target triangle edge and the vertex;
the bone point fitting point searching module is used for searching the bone point fitting points;
a bone point fitting point processing module for processing the bone point fitting points to obtain fitted bone points; and
and the one-dimensional Hermite interpolation processing module is used for interpolating the fitted bone points according to the distance between the bone points.
9. A computer terminal comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program implements the steps of the STL-based bent-tube model skeleton extraction method as recited in any one of claims 1 to 7.
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