CN105303617A - Recursive curved surface generating method and device on the basis of quadrangle segmentation - Google Patents

Abstract

An embodiment of the invention discloses a recursive curved surface generating method and device on the basis of quadrangle segmentation. The method comprise the steps of scanning an object to obtain corresponding discrete three-dimensional point cloud data; utilizing a Delaunay triangulation algorithm to preprocess the three-dimensional point cloud data and obtaining a good data structure; merging an interpolation subdivision method and iterating according to a recursive equation to generate new vertexes and a new quadrangle surface piece; conducting iteration for corresponding times according to a needed fine degree; drawing every new quadrangle surface piece after the iteration is completed, and displaying a three-dimensional model of the object. According to the embodiment, the recursive display method merging the classical Catmull-Clark method and the interpolation subdivision method is used. A smooth three-dimensional model created by the novel interpolation subdivision method through subdivision of a rough three-dimensional model is a little bit smaller than a real model. The novel method enables accurate shape-preserving display closest to the real model and better achieves gradual quick accurate display of a three-dimensional model.

Description

One cuts point lower recurrence surface generation method and a device thereof towards quadrilateral

Technical field

The present invention relates to three-dimensional imaging display technique field, particularly relate to one and cut point lower recurrence surface generation method and a device thereof towards quadrilateral.

Background technology

Along with the design of industrial products is towards variation, particularization, the complicated future development of topological structure, the limitation of present parametric surface formative method is more and more obvious, because representation of a surface method is when the body surface of complex structure topological structure, need to carry out cutting or splicing to patch, not only time-consuming, and there is numerical error, and bent point curved surface can overcome the deficiency of parametric surface, can represent randomly topologically structured curved surface, algorithm is simple.

According to segmenting the trellis-type generated, triangle is had to segment pattern, quadrilateral segmentation pattern, hexagon segmentation pattern and polygon subdivision pattern, Catmull-Clark pattern is based on the classical quadrilateral subdivision pattern of the one of approaching, and compares true model bigger than normal with the three-dimensional model that the method obtains.

But it is less than normal to compare true model based on the three-dimensional model that the method for interpolation obtains.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, the invention provides one and cut point lower recurrence surface generation method and a device thereof towards quadrilateral, the progressive accurately display fast to three-dimensional model can be realized better.

In order to solve the problem, the present invention proposes one and cut a point lower recurrence surface generation method towards quadrilateral, described method comprises:

Scanning is carried out to object and obtains corresponding discrete three dimensional point cloud;

Utilize Delaunay triangulation to carry out corresponding pre-service to three dimensional point cloud and obtain good data structure;

Merge interpolation subdividing method according to the new summit of recurrence formula grey iterative generation and new quad patch;

According to the corresponding number of times of required fine degree iteration, after completing, each new quad patch of drafting, demonstrates object dimensional model.

Preferably, the described Delaunay of utilization triangulation is carried out to three dimensional point cloud the step that corresponding pre-service obtains good data structure and is comprised:

Construct a triangular, comprise all loose points, put into triangle chained list;

The loose point that point is concentrated is inserted successively, the triangle that circumscribed circle comprises insertion point is found out in triangle chained list, delete the leg-of-mutton common edge of impact, insertion point is coupled together with the leg-of-mutton whole summit of impact, completes the insertion of a point in Delaunay triangle chained list;

According to Optimality Criteria to the new Triangles Optimization formed in local, the triangle of formation is put into Delaunay triangle chained list;

Circulation performs 3 above-mentioned insertion steps and plays, until all loose insertions are complete.

Preferably, in the described Delaunay of the utilization triangulation of execution, corresponding pre-service is carried out to three dimensional point cloud and obtain in the process of good data structure, by respective handling structure three-dimensional model file.

Preferably, described fusion interpolation subdividing method, according to the step of the new summit of recurrence formula grey iterative generation and new quad patch, comprising:

Corresponding three-dimensional model file is read in internal memory and stores with half of list structure;

Catmull-Clark comprehensively based on quadrilateral approaches and the recursive models of interpolation subdividing pattern acquisition containing a parameter alpha.

Correspondingly, the present invention also provides a kind of and cuts a point lower recurrence surface generating apparatus towards quadrilateral, and described device comprises:

Scan module, obtains corresponding discrete three dimensional point cloud for carrying out scanning to object;

Pretreatment module, carries out corresponding pre-service for utilizing Delaunay triangulation to three dimensional point cloud and obtains good data structure;

Dough sheet generation module, for merging interpolation subdividing method according to the new summit of recurrence formula grey iterative generation and new quad patch;

Display module, for according to the corresponding number of times of required fine degree iteration, after completing, each new quad patch of drafting, demonstrates object dimensional model.

Preferably, described pretreatment module comprises:

Tectonic element, for constructing a triangular, comprising all loose points, putting into triangle chained list;

Plug-in unit, loose point for being concentrated by point inserts successively, the triangle that circumscribed circle comprises insertion point is found out in triangle chained list, delete the leg-of-mutton common edge of impact, insertion point is coupled together with the leg-of-mutton whole summit of impact, completes the insertion of a point in Delaunay triangle chained list;

Optimize unit, for according to the Triangles Optimization of Optimality Criteria to the new formation in local, the triangle of formation is put into Delaunay triangle chained list; Circulation performs 3 above-mentioned insertion steps and plays, until all loose insertions are complete.

Preferably, described pretreatment module also obtains in the step process of good data structure for carrying out corresponding pre-service in the described Delaunay of the utilization triangulation of execution to three dimensional point cloud, by respective handling structure three-dimensional model file.

Preferably, described dough sheet generation module comprises:

Storage unit, for reading in internal memory by corresponding three-dimensional model file and storing with half of list structure;

Model acquiring unit, approaches for the comprehensive Catmull-Clark based on quadrilateral and obtains with interpolation subdividing pattern the recursive models containing a parameter alpha.

In embodiments of the present invention, employ the recurrence surface display packing merging classical Catmull-Clark and interpolation subdividing pattern, new interpolation subdividing method will be less than normal than true model to the smooth three-dimensional model that coarse three-dimensional model segments, the new recurrence surface display packing of the band parameter merged can accomplish that the conformal the most close with true model accurately shows, and can realize the progressive accurately display fast to three-dimensional model better.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the schematic flow sheet cutting point lower recurrence surface generation method towards quadrilateral of the embodiment of the present invention;

Fig. 2 is the structure composition schematic diagram cutting point lower recurrence surface generating apparatus towards quadrilateral of the embodiment of the present invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Fig. 1 is the schematic flow sheet cutting point lower recurrence surface generation method towards quadrilateral of the embodiment of the present invention, and as shown in Figure 1, the method comprises:

S1, carries out scanning to object and obtains corresponding discrete three dimensional point cloud;

S2, utilizes Delaunay triangulation to carry out corresponding pre-service to three dimensional point cloud and obtains good data structure;

S3, merges interpolation subdividing method according to the new summit of recurrence formula grey iterative generation and new quad patch;

S4, according to the corresponding number of times of required fine degree iteration, after completing, each new quad patch of drafting, demonstrates object dimensional model.

Wherein, S2 comprises:

Construct a triangular, comprise all loose points, put into triangle chained list;

The loose point that point is concentrated is inserted successively, the triangle that circumscribed circle comprises insertion point is found out in triangle chained list, delete the leg-of-mutton common edge of impact, insertion point is coupled together with the leg-of-mutton whole summit of impact, completes the insertion of a point in Delaunay triangle chained list;

According to Optimality Criteria to the new Triangles Optimization formed in local, the triangle of formation is put into Delaunay triangle chained list;

Circulation performs 3 above-mentioned insertion steps and plays, until all loose insertions are complete.

Wherein, good data structure file to refer at the conventional three-dimensional model file formed by respective handling as obj, off, 3dx, stl etc., stores corresponding summit, quad patch, the information such as Texture Coordinates.

In concrete enforcement, utilize Delaunay triangulation to carry out corresponding pre-service to three dimensional point cloud in execution and obtain in the process of good data structure, by respective handling structure three-dimensional model file.

S3 comprises further:

Corresponding three-dimensional model file is read in internal memory and stores with half of list structure; Half of table has efficient calculation efficiency;

Catmull-Clark comprehensively based on quadrilateral approaches and the recursive models of interpolation subdividing pattern acquisition containing a parameter alpha.

Half of list structure needs to store some relevant informations for summit, one side of something and face in above process, and wherein corresponding construction is:

Summit structure:

structHE_vert

{

Floatx, y, z; The x, y, z coordinate figure on // summit

HE_edge*edge; // half of the pointer that is starting point with this

Intindex; // vertex index

}；

Half-edge Structure:

structHE_edge

{

HE_vert*vert; The starting point pointer on // this limit

HE_face*face; The face pointer at // this place, limit

HE_edge*next; Next half of pointer in // this face, place, limit

HE_edge*pair; The relatively half of pointer on // this limit

}；

Face structure:

structHE_face

{

HE_edge*edge; Any half of pointer in // this face

}；

If polygonal initial network control vertex has P _i(i=0,1 ..., n), so:

$\left\{\begin{array}{c}{Q}_i^0=P_i,i=0,1,...,n\\ Q_j^r=f\left(Q_i^{r-1}\right),i=0,1,...,n\\ Q_j^{r^{\′}}=g\left(Q_j^r\right),j=0,1,...,n,\mathrm{....},n+m\end{array}\right.$

Utilize old summit to generate new summit, f can be different mappings; Mobile respective vertices, but g different mappings.

Its concrete steps are as follows:

(1) F-summit: after reposition is moved to for each new vertex of surface, v _i(i=1...n) be the former summit of definition face f, e _i(i=1...n) be the limit of face f, so displacement is:

$-\mathrm{\α}\left(\frac{\underset{i=1}{\overset{n}{\Σ}}{F}_i}{n^2}+\frac{2\underset{i=1}{\overset{n}{\Σ}}{E}_i}{n^2}+\frac{(-3)v}{n}\right)$

Wherein F _iall and v _ithe mean value of adjacent vertex, E _iwith e _ifor the mean value of the new vertex of surface of all of common edge, n is all number of vertex defining face f.

(2) E-summit: after moving to reposition for summit, new limit, each inside, its displacement is:

$-\mathrm{\α}\left(-\frac{P}{2}+\frac{\underset{j=1}{\overset{2}{\Σ}}{Q}_j}{4}\right)+\left(1-\mathrm{\α}\right)\left(-\frac{P^{\′}}{2}+\frac{\underset{j=1}{\overset{2}{\Σ}}{Q}_j^{\′}}{4}\right)$

V _j(j=0,1) is two summits on a definition limit, and wherein P is the average of the new vertex of surface in two faces containing a common edge, Q _jcomprise vertex v _jthe average of the new vertex of surface of all, P' is the average on two the former summits defining limit, Q _j' (j=0,1) be the average of facing the former summit connecing a limit.

(3) V-summit: if the border vertices of the 1-ring of internal vertex v is followed successively by v ₀, v ₁..., v _2n-1, wherein n=|v| _e, after moving to reposition for old summit, each inside, displacement is:

$(1-\mathrm{\α})(\frac{\underset{i=1}{\overset{n}{\Σ}}{F}_i}{n^2}+\frac{2\underset{i=1}{\overset{n}{\Σ}}{E}_i}{n^2}+\frac{(-3)v}{n})$

Wherein F _ithe mean value of all and former vertex v adjacent vertex, E _icomprise summit _vthe average on head and the tail summit on all limits, n is the limit number adjacent with summit.

(4), after for Xin Bian summit, border, it moves to reposition, its displacement is:

$-\mathrm{\α}(-\frac{v_1}{8}+\frac{v}{4}+\frac{v_2}{8})$

V ₁and v ₂it is the summit, new limit on two limits containing vertex v.

(5), after for former summit, border, it moves to reposition, its displacement is:

$(1-\mathrm{\α})(-\frac{v_1}{8}+\frac{v}{4}+\frac{v_2}{8})$

V ₁and v ₂with 2 adjacent on one side points with vertex v.

Correspondingly, the embodiment of the present invention also provides a kind of and cuts a point lower recurrence surface generating apparatus towards quadrilateral, and as shown in Figure 2, this device comprises:

Scan module 1, obtains corresponding discrete three dimensional point cloud for carrying out scanning to object;

Pretreatment module 2, carries out corresponding pre-service for utilizing Delaunay triangulation to three dimensional point cloud and obtains good data structure;

Dough sheet generation module 3, for merging interpolation subdividing method according to the new summit of recurrence formula grey iterative generation and new quad patch;

Display module 4, for according to the corresponding number of times of required fine degree iteration, after completing, each new quad patch of drafting, demonstrates object dimensional model.

Wherein, pretreatment module 2 comprises:

Tectonic element, for constructing a triangular, comprising all loose points, putting into triangle chained list;

Plug-in unit, loose point for being concentrated by point inserts successively, the triangle that circumscribed circle comprises insertion point is found out in triangle chained list, delete the leg-of-mutton common edge of impact, insertion point is coupled together with the leg-of-mutton whole summit of impact, completes the insertion of a point in Delaunay triangle chained list;

Optimize unit, for according to the Triangles Optimization of Optimality Criteria to the new formation in local, the triangle of formation is put into Delaunay triangle chained list; Circulation performs 3 above-mentioned insertion steps and plays, until all loose insertions are complete.

Pretreatment module 2 also obtains in the step process of good data structure for utilizing Delaunay triangulation to carry out corresponding pre-service to three dimensional point cloud in execution, by respective handling structure three-dimensional model file.

Dough sheet generation module 3 comprises:

Storage unit, for reading in internal memory by corresponding three-dimensional model file and storing with half of list structure;

Model acquiring unit, approaches for the comprehensive Catmull-Clark based on quadrilateral and obtains with interpolation subdividing pattern the recursive models containing a parameter alpha.

In device embodiment of the present invention, the function of each functional module see the flow processing in the inventive method embodiment, can repeat no more here.

In embodiments of the present invention, employ the recurrence surface display packing merging classical Catmull-Clark and interpolation subdividing pattern, new interpolation subdividing method will be less than normal than true model to the smooth three-dimensional model that coarse three-dimensional model segments, the new recurrence surface display packing of the band parameter merged can accomplish that the conformal the most close with true model accurately shows, and can realize the progressive accurately display fast to three-dimensional model better.

One of ordinary skill in the art will appreciate that all or part of step in the various methods of above-described embodiment is that the hardware that can carry out instruction relevant by program has come, this program can be stored in a computer-readable recording medium, storage medium can comprise: ROM (read-only memory) (ROM, ReadOnlyMemory), random access memory (RAM, RandomAccessMemory), disk or CD etc.

In addition, above to the embodiment of the present invention provide to cut point lower recurrence surface generation method towards quadrilateral and device is described in detail, apply specific case herein to set forth principle of the present invention and embodiment, the explanation of above embodiment just understands method of the present invention and core concept thereof for helping; Meanwhile, for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.

Claims (8)

1. one kind is cut a point lower recurrence surface generation method towards quadrilateral, and it is characterized in that, described method comprises:

Scanning is carried out to object and obtains corresponding discrete three dimensional point cloud;

Utilize Delaunay triangulation to carry out corresponding pre-service to three dimensional point cloud and obtain good data structure;

Merge interpolation subdividing method according to the new summit of recurrence formula grey iterative generation and new quad patch;

According to the corresponding number of times of required fine degree iteration, after completing, each new quad patch of drafting, demonstrates object dimensional model.

2. as claimed in claim 1 cut a point time recurrence surface generation method towards quadrilateral, it is characterized in that, the described Delaunay of utilization triangulation is carried out to three dimensional point cloud the step that corresponding pre-service obtains good data structure and is comprised:

Construct a triangular, comprise all loose points, put into triangle chained list;

The loose point that point is concentrated is inserted successively, the triangle that circumscribed circle comprises insertion point is found out in triangle chained list, delete the leg-of-mutton common edge of impact, insertion point is coupled together with the leg-of-mutton whole summit of impact, completes the insertion of a point in Delaunay triangle chained list;

According to Optimality Criteria to the new Triangles Optimization formed in local, the triangle of formation is put into Delaunay triangle chained list;

Circulation performs 3 above-mentioned insertion steps and plays, until all loose insertions are complete.

3. cut a point lower recurrence surface generation method towards quadrilateral as claimed in claim 2, it is characterized in that, carrying out corresponding pre-service in the described Delaunay of the utilization triangulation of execution to three dimensional point cloud obtains in the process of good data structure, by respective handling structure three-dimensional model file.

4. as claimed in claim 1 cut a point time recurrence surface generation method towards quadrilateral, it is characterized in that, described fusion interpolation subdividing method, according to the step of the new summit of recurrence formula grey iterative generation and new quad patch, comprising:

Corresponding three-dimensional model file is read in internal memory and stores with half of list structure;

Catmull-Clark comprehensively based on quadrilateral approaches and the recursive models of interpolation subdividing pattern acquisition containing a parameter alpha.

5. cut a point lower recurrence surface generating apparatus towards quadrilateral, it is characterized in that, described device comprises:

Scan module, obtains corresponding discrete three dimensional point cloud for carrying out scanning to object;

Pretreatment module, carries out corresponding pre-service for utilizing Delaunay triangulation to three dimensional point cloud and obtains good data structure;

Dough sheet generation module, for merging interpolation subdividing method according to the new summit of recurrence formula grey iterative generation and new quad patch;

Display module, for according to the corresponding number of times of required fine degree iteration, after completing, each new quad patch of drafting, demonstrates object dimensional model.

6. cut a point lower recurrence surface generating apparatus towards quadrilateral as claimed in claim 5, it is characterized in that, described pretreatment module comprises:

Tectonic element, for constructing a triangular, comprising all loose points, putting into triangle chained list;

Plug-in unit, loose point for being concentrated by point inserts successively, the triangle that circumscribed circle comprises insertion point is found out in triangle chained list, delete the leg-of-mutton common edge of impact, insertion point is coupled together with the leg-of-mutton whole summit of impact, completes the insertion of a point in Delaunay triangle chained list;

Optimize unit, for according to the Triangles Optimization of Optimality Criteria to the new formation in local, the triangle of formation is put into Delaunay triangle chained list; Circulation performs 3 above-mentioned insertion steps and plays, until all loose insertions are complete.

7. cut a point lower recurrence surface generating apparatus towards quadrilateral as claimed in claim 6, it is characterized in that, described pretreatment module also obtains in the step process of good data structure for carrying out corresponding pre-service in the described Delaunay of the utilization triangulation of execution to three dimensional point cloud, by respective handling structure three-dimensional model file.

8. cut a point lower recurrence surface generating apparatus towards quadrilateral as claimed in claim 5, it is characterized in that, described dough sheet generation module comprises:

Storage unit, for reading in internal memory by corresponding three-dimensional model file and storing with half of list structure;

Model acquiring unit, approaches for the comprehensive Catmull-Clark based on quadrilateral and obtains with interpolation subdividing pattern the recursive models containing a parameter alpha.