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NARVAL >> NARVAL > NARVAL_IP_CornerObject

NARVAL_IP_CornerObject

Extract the corners of the ith object of an obstacle (Multi-Rectangles).

Calling Sequence

[xsi,ysi] = NARVAL_IP_CornerObject(xs,ys,ns,i)

Parameters

xs :

x-coordinate of corners.

ys :

y-coordinate of corners.

ns :

quantity of corners per object (vector).

i :

object index.

xsi :

x-coordinate of corners of the ith object.

ysi :

y-coordinate of corners of the ith object.

Description

NARVAL_IP_CornerObject extracts the corners of the ith object of an obstacle created with Multi-Rectangles (see NARVAL_IP_RectObstacles). After a false detection scheme, real corners coordinates are stored in [xs,ys]. ns 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);
grayplot(1:Contx,1:Conty,Cont);
xset("colormap",graycolormap(128));
w3=3;//window index
scf(w3);
clf(w3);
[Dim]=NARVAL_IP_DistanceMap(Pz,Cont);//creation of the distance map
[Dimx,Dimy]=size(Dim);//image size
grayplot(1:L/z,1:L/z,Dim);//graph visualization
xset("colormap",graycolormap(128));
HL1=[0 -1 0;-1 4 -1;0 -1 0];//kernel 1
HL2=[-1 -1 -1;-1 8 -1;-1 -1 -1];//kernel 2
[Dim1]=NARVAL_IP_Conv2(Dim,HL2);//convolution
[Dim1x,Dim1y]=size(Dim1);//image size
w4=4;//window index
scf(w4);
clf(w4);
grayplot(1:Dim1x,1:Dim1y,Dim1);
xset("colormap",graycolormap(128));
wm=3;//parameter
[cornerz]=NARVAL_IP_Moravec(Pz,wm);//extraction of corners
T=(max(cornerz)+min(cornerz))/2;//threshold
[cornerT]=NARVAL_IP_MoravecT(cornerz,T);//application of a threshold
[cornerTx,cornerTy]=size(cornerT);//image size 
w5=5;//window index
scf(w5);
clf(w5);
grayplot(1:cornerTx,1:cornerTy,cornerT);//graph visualization
xset("colormap",graycolormap(128));
[x,y,direction,n]=NARVAL_IP_ObstCorners(Cont);//Corners detection
lc=2;//parameters
DT=3;
Tcorel=1;
Tgrad=1;
[xs,ys,ns]=NARVAL_IP_ObstCornersDet(x,y,direction,n,lc,Tcorel,Tgrad,DT);//remove false detections
for kl=1:length(ns)
[xsi,ysi]=NARVAL_IP_CornerObject(xs,ys,ns,kl);//application of NARVAL_IP_CornerObject 
[xsi;ysi]
end

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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