CN1870056A - Method for obtaining B-shaped bar curve in visual simulation - Google Patents

Abstract

A method for obtaining B sample bar curved surface in visual simulation includes obtaining point coordinate Vo of network line when initialization is carried out and curved is divided from middle, deciding point coordinate V1 of network line on curved surface by original control point and deciding point coordinate value V2 of network line on curved surface by moved control point then calculating Vo+( V 2 -V1 ) value being used as vector of B sample bar curved surface in visual simulation.

Description

Obtain the method for B-spline surface in the vision simulation

Technical field

The present invention relates to the Scene Simulation field, relate in particular to the method that obtains B-spline surface in a kind of vision simulation.

Background technology

In the Scene Simulation application process, need to utilize B batten (reasonable B batten heterogeneous) curved surface to carry out image simulation.And good B-spline surface can guarantee the optimum efficiency of image simulation.

Described B-spline surface is particularly useful for creating complicated surface modeling, uses the B batten can make the structure of the unapproachable oiling curved surface of solid modelling in the past, becomes simple, convenient.Specifically can adjust the structure that the point that constitutes curved surface is finished complex-curved moulding alternately by form.

At present, acquisition B-spline surface equation is as follows:

U is defined as to the B-spline surface on q rank to p rank, v:

$S(u,v)=\frac{\underset{i=0}{\overset{n}{\&Sum;}}\underset{j=0}{\overset{m}{\&Sum;}}{N}_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}{P}_{i,j}}{\underset{i=0}{\overset{n}{\&Sum;}}\underset{j=0}{\overset{m}{\&Sum;}}{N}_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,\mathrm{<figure-callout\; id="0"\; label="j"\; filenames="A20051007211300102.png"\; state="\{\{state\}\}">j</figure-callout>}}}0\&le;u,v\&le;1;$

In the formula, { P _{I, j}For constituting the curved surface net of control points;

{ ω _{I, j}It is weight factor;

{ N _{I, p (u)}, { N _{J, q are (v)}Being respectively p rank, q rank B spline base function, its knot vector is:

U＝{0，…，0，u _p+1，…，u _r-p-1，1，…，1}；

V＝{0，…，0，v _q+1，…，v _s-q-1，1，…，1}；

Here, r=n+p+1, s=m+q+1;

Order: $R_{i,j}(u,v)=\frac{N_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}}{\underset{k=0}{\overset{n}{\&Sum;}}\underset{l=0}{\overset{m}{\&Sum;}}{N}_{k,p}\left(u\right)N_{l,q}\left(v\right){\mathrm{\&omega;}}_{k,l}};$

Corresponding B-spline surface equation also can be:

$S(u,v)=\underset{i=0}{\overset{n}{\&Sum;}}\underset{j=0}{\overset{m}{\&Sum;}}{R}_{i,j}(u,v)P_{i,j};$

In existing B-spline surface equation, because:

U＝{0，…，0，u _p+1，…，u _r-p-1，1，…，1}；

V＝{0，…，0，v _q+1，…，v _s-q-1，1，…，1}。

Therefore, prior art can guarantee it by five equilibrium for the single order curved surface, as shown in Figure 1, has provided a curved surface that comprises 9*7 reference mark among Fig. 1, and whole curved surface is by 16*16 lattice five equilibrium.

Yet along with the growth of calculating exponent number, corresponding curved surface is incited somebody to action respectively:

Expanded the individual point of 2 (p-1) in the horizontal direction,

Expanded the individual point of 2 (q-1) in vertical direction,

Thereby cause the not five equilibrium of curved surface control domain, and as shown in Figure 2, the interval of peripheral control line is increasing, and this obviously can't satisfy the requirement of vision simulation.

Summary of the invention

In view of above-mentioned existing in prior technology problem, the purpose of this invention is to provide the method that obtains B-spline surface in a kind of vision simulation, so that obtain the B-spline surface of five equilibrium accurately, improve the effect of vision simulation.

The objective of the invention is to be achieved through the following technical solutions:

The invention provides the method that obtains B-spline surface in a kind of vision simulation, comprising:

A, the point coordinate V0 of grid line during halving curved surface when obtaining initialization, by the point coordinate V1 of grid line on the curved surface of former reference mark decision, and by the point coordinate value V2 of grid line on the curved surface of the reference mark decision after moving;

B, calculating V0+ (V2-V1) value, and as all curved surface vectors of the B in the vision simulation.

During described initialization during halving curved surface the point coordinate V0 of grid line calculate according to existing B-spline surface formula to obtain.

Described point coordinate V1 by grid line on the curved surface of former reference mark decision calculates according to existing B-spline surface formula to obtain.

Described point coordinate value V2 by grid line on the curved surface of the reference mark decision after moving calculates according to existing B-spline surface formula to obtain.

Described existing B-spline surface formula comprises:

U to p rank, v to the B-spline surface formula definition on q rank is:

$S(u,v)=\frac{\underset{i=0}{\overset{n}{\&Sum;}}\underset{j=0}{\overset{m}{\&Sum;}}{N}_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}{P}_{i,j}}{\underset{i=0}{\overset{n}{\&Sum;}}\underset{j=0}{\overset{m}{\&Sum;}}{N}_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,\mathrm{<figure-callout\; id="0"\; label="j"\; filenames="A20051007211300102.png"\; state="\{\{state\}\}">j</figure-callout>}}}0\&le;u,v\&le;1;$

In the formula, { P _{I, j}For constituting the curved surface net of control points;

{ ω _{I, j}It is weight factor;

{ N _{I, p (u)}, { N _{J, q are (v)}Being respectively p rank, q rank B spline base function, its knot vector is:

U＝{0，…，0，u _p+1，…，u _r-p-1，1，…，1}；

V＝{0，…，0，v _q+1，…，v _s-q-1，1，…，1}；

Here, r=n+p+1, s=m+q+1.

Order: $R_{i,j}(u,v)=\frac{N_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}}{\underset{k=0}{\overset{n}{\&Sum;}}\underset{l=0}{\overset{m}{\&Sum;}}{N}_{k,p}\left(u\right)N_{l,q}\left(v\right){\mathrm{\&omega;}}_{k,l}}.$

Described existing B-spline surface formula comprises:

$S(u,v)=\underset{i=0}{\overset{n}{\&Sum;}}\underset{j=0}{\overset{m}{\&Sum;}}{R}_{i,j}(u,v)P_{i,j};$

Wherein:

U＝{0，…，0，u _p+1，…，u _r-p-1，1，…，1}；

V＝{0，…，0，v _q+1，…，v _s-q-1，1，…，1}。

As seen from the above technical solution provided by the invention, the present invention adopts the error concealment of V2-V1 with the B-spline surface of acquisition, has guaranteed other characteristic of B-spline surface simultaneously again.Realization of the present invention can effectively overcome the increasing problem in interval that occurs peripheral control line in the prior art along with the increase of calculating exponent number.That is to say, based on method provided by the invention, under any calculating exponent number, the B-spline surface of five equilibrium accurately that all can obtain.

Description of drawings

Fig. 1 is based on the single order B-spline surface that obtains in the prior art;

Fig. 2 is the second order B-spline surface that obtains based on prior art;

Fig. 3 is the second order B-spline surface that obtains based on the present invention;

The B-spline surface of using in the vision simulation of Fig. 4 for the present invention's acquisition.

Embodiment

Core of the present invention is that existing curved surface formula is adjusted conversion, thereby obtains the B-spline surface of five equilibrium accurately.

In order to guarantee other characteristic of B-spline surface, avoid the not situation of five equilibrium again simultaneously, the computing formula of the B-spline surface that method of the present invention adopts in the specific implementation process is specially:

V3＝V0+(V2-V1))；

Wherein:

V3: be the arbitrfary point vector on the curved surface, be the curved surface vector that finally will obtain;

V0: point coordinate during halving curved surface during for initialization, can adopt the existing B spline formula that provides in the background technology to calculate and obtain;

V1: for pressing p in current reference mark ^*The point coordinate that point coordinate during q rank B-spline surface initialization, V1 calculate by grid line on the curved surface of original reference mark decision; Specifically can adopt the existing B spline formula that provides in the background technology to calculate obtains;

V2: for the reference mark changes back p ^*The point coordinate of q rank B-spline surface, V2 are the point coordinate by grid line on the curved surface of the reference mark decision after moving that calculates; Equally, can adopt the existing B spline formula that provides in the background technology to calculate obtains.

Utilize the invention described above to provide the B-spline surface computing formula to obtain the curved surface that vision simulation needs, and carry out corresponding vision simulation based on described curved surface and handle, so just can obtain the preferable vision simulation effect of effect.

Adopt the error concealment of V2-V1 among the present invention, guaranteed other characteristic of B-spline surface simultaneously again the B-spline surface of acquisition.

As shown in Figure 3, the interval of the peripheral control line of the surface of second order that obtains based on the present invention is five equilibrium still, has guaranteed the effect of vision simulation.

Fig. 4 has provided the concrete application synoptic diagram of method of the present invention, as can be seen, can obtain at interval B-spline surface uniformly based on the present invention, can obtain vision simulation effect preferably based on such B-spline surface.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.

Claims (6)

1, obtain the method for B-spline surface in a kind of vision simulation, it is characterized in that, comprising:

A, the point coordinate V0 of grid line during halving curved surface when obtaining initialization, by the point coordinate V1 of grid line on the curved surface of former reference mark decision, and by the point coordinate value V2 of grid line on the curved surface of the reference mark decision after moving;

B, calculating V0+ (V2-V1) value, and as all curved surface vectors of the B in the vision simulation.

2, obtain the method for B-spline surface in the vision simulation according to claim 1, it is characterized in that, during described initialization during halving curved surface the point coordinate V0 of grid line calculate acquisition according to existing B-spline surface formula.

3, obtain the method for B-spline surface in the vision simulation according to claim 1, it is characterized in that, described point coordinate V1 by grid line on the curved surface of former reference mark decision calculates according to existing B-spline surface formula to obtain.

According to the method that obtains B-spline surface in claim 1, the 2 or 3 described vision simulations, it is characterized in that 4, described point coordinate value V2 by grid line on the curved surface of the reference mark decision after moving calculates according to existing B-spline surface formula to obtain.

5, obtain the method for B-spline surface in the vision simulation according to claim 4, it is characterized in that described existing B-spline surface formula comprises:

U to p rank, v to the B-spline surface formula definition on q rank is:

$S(u,v)=\frac{\underset{i=0}{\overset{n}{\mathrm{\&Sigma;}}}\underset{j=0}{\overset{m}{\mathrm{\&Sigma;}}}{N}_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}{P}_{i,j}}{\underset{i=0}{\overset{n}{\mathrm{\&Sigma;}}}\underset{j=0}{\overset{m}{\mathrm{\&Sigma;}}}{N}_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}}0\&le;u,v\&le;1;$

In the formula, { P _{I, j}For constituting the curved surface net of control points;

{ ω _{I, j}It is weight factor;

{ N _{I, p (u)}, { N _{J, q are (v)}Being respectively p rank, q rank B spline base function, its knot vector is:

U＝{0，...，0，u _p+1，...，u _r-p-1，1，...，1}；

V＝{0，...，0，V _q+1，...，V _s-q-1，1，...，1}；

Here, r=n+p+1, s=m+q+1;

Order: $R_{i,j}(u,v)=\frac{N_{i,p}\left(u\right)N_{j,q}\left(v\right){\mathrm{\&omega;}}_{i,j}}{\underset{k=0}{\overset{n}{\mathrm{\&Sigma;}}}\underset{l=0}{\overset{m}{\mathrm{\&Sigma;}}}{N}_{k,p}\left(u\right)N_{l,q}\left(v\right){\mathrm{\&omega;}}_{k,l}}.$

6, obtain the method for B-spline surface in the vision simulation according to claim 4, it is characterized in that described existing B-spline surface formula comprises:

$S(u,v)=\underset{i=0}{\overset{n}{\mathrm{\&Sigma;}}}\underset{j=0}{\overset{m}{\mathrm{\&Sigma;}}}{R}_{i,j}(u,v)P_{i,j};$

Wherein:

U＝{0，...，0，u _p+1，...，u _r-p-1，1，...，1}；

V＝{0，...，0，v _q+1，...，v _s-q-1，1，...，1}。

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