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NARVAL >> NARVAL > NARVAL_IP_ObstCornersDet

NARVAL_IP_ObstCornersDet

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

Calling Sequence

[xs,ys,ns] = NARVAL_IP_ObstCornersDet(x,y,d,n,lc,Tc,Tg,dt)

Parameters

x :

x-coordinates of corners.

y :

y-coordinates of corners.

d :

direction vector.

n :

length vector.

lc :

correlation mode.

Tc :

correlation threshold.

Tg :

gradient threshold.

dt :

minimum distance between two corners.

xs :

x-coordinate of corners.

ys :

y-coordinate of corners.

ns :

length vector.

Description

NARVAL_IP_ObstCornersDet extracts the corners of the obstacle contour defined by the coordinates of the corner [x,y] (see NARVAL_IP_ObstCorners) and removes false detections in respect with the two thresholds Tc and Tg. d gives the direction vector ([1 2 3 4 5 6 7 8]) of each corner found in each object. n provides the numbers of corners for each object. lc represents the correlation mode, e.g. the kernel width: 1:+x+, 2:++x++ and 3:+++x+++. dt is the minimum distance between two corners. After a false detection scheme, real corners coordinates are stored in [xs,ys]. ns finally 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);//application of NARVAL_IP_ObstCornersDet
xs
ys
ns

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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