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NARVAL >> NARVAL > NARVAL_IP_ObstCornersDR

NARVAL_IP_ObstCornersDR

Extract the corners of an obstacle contour (false detection removal and angle threshold).

Calling Sequence

[xsd,ysd,nsd] = NARVAL_IP_ObstCornersDR(xs,ys,ns,a)

Parameters

xs :

x-coordinate of corners.

ys :

y-coordinate of corners.

ns :

length vector.

a :

angle threshold.

xsd :

updated x-coordinate of corners.

ysd :

updated y-coordinate of corners.

nsd :

updated length vector.

Description

NARVAL_IP_ObstCornersDR extracts the real corners of the obstacle contour defined by current corners performed by NARVAL_IP_ObstCornersDet (false detection removal and angle threshold a). Corners coordinates are stored in [xs,ys] (updated to [xsd,ysd]). ns (updated to nsd) provides the number of corners for each obstacle.

Examples

dt=getdate();
seed=dt(10);
rand('seed',seed);//initialization of the random values generator
no=4;//quantity of obstacles (rectangle)
L=1000;//squared area side
hm=100;//minimal height
hM=250;//maximal height
wm=100;//minimal width
wM=250;//maximal width
Al=[0 %pi/2 %pi -%pi/2];//available angles for obstacles
[Xs,Ys,X,Y,H,W,A]=NARVAL_IP_RectObstacles(no,L,hm,hM,wm,wM);//generation of obstacles
[P]=NARVAL_IP_PotentialRot(X,Y,H,W,A,L);//generation of obstacle matrix
z=10;//zoom factor
o=2;// 1=mean, 2=max, 3=min, 4=median
Pz=NARVAL_IP_MRA(P,z,o);//scale modification
[Pzx,Pzy]=size(Pz);//image size
w1=1;//window index
w2=2;//window index
scf(w1);
clf(w1);
grayplot(1:Pzx,1:Pzy,Pz);//graph visualization
xset("colormap",graycolormap(128));
scf(w2);
clf(w2);
[PEz]=NARVAL_IP_Erosion(Pz);//contour performance
Cont=Pz-PEz;//contour 1
[Contx,Conty]=size(Cont);//image size
grayplot(1:Contx,1:Conty,Cont);//graph visualization
xset("colormap",graycolormap(128));
[x,y,direction,n]=NARVAL_IP_ObstCorners(Cont);//Corners detection
lc=2;//correlation mode
DT=3;//minimum distance between two corners
Tcorel=1;//threshold
Tgrad=1;//threshold
[xs,ys,ns]=NARVAL_IP_ObstCornersDet(x,y,direction,n,lc,Tcorel,Tgrad,DT);//False detection removal
a=0.3;//angle threshold
[xsd,ysd,nsd]=NARVAL_IP_ObstCornersDR(xs,ys,ns,a);//application of NARVAL_IP_ObstCornersDR
[g]=NARVAL_IP_VisGraph(xs,ys,ns,Pz);//creation of the visibility graph for [xs,ys]
w3=3;
g.node_x=g.node_x*z;
g.node_y=g.node_y*z;
NARVAL_G_ShowGraph(g,w3);//graph visualization
[gs]=NARVAL_IP_VisGraph(xsd,ysd,nsd,Pz);//creation of the visibility graph for [xsd,ysd]
w4=4;
gs.node_x=gs.node_x*z;
gs.node_y=gs.node_y*z;
NARVAL_G_ShowGraph(gs,w4);//graph visualization

Authors

Foued Melakessou

Contact

Dr. Foued Melakessou

Research Associate

Interdisciplinary Centre for Security, Reliability and Trust

Room F106

University of Luxembourg

6, rue Coudenhove Kalergi

L-1359 Luxembourg-Kirchberg

E-mail: foued.melakessou@uni.lu

Tel: (+352) 46 66 44 5346

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