<< holder Post-Processing or Help to the Interpretation margtfr >>

Time Frequency Toolbox >> Time Frequency Toolbox > Post-Processing or Help to the Interpretation > htl

htl

Hough transform for detection of lines in images.

Calling Sequence

[HT,RHO,THETA]=HTL(IM)
[HT,RHO,THETA]=HTL(IM,M,)
[HT,RHO,THETA]=HTL(IM,M,N)
[HT,RHO,THETA]=HTL(IM,M,N,TRACE)
[HT,RHO,THETA]=HTL(...,'plot')

Parameters

IM :

image to be analyzed (size Xmax x Ymax).

M :

desired number of samples along the radial axis (default : Xmax).

N :

desired number of samples along the azimutal (angle) axis (default : Ymax).

TRACE :

if nonzero, the progression of the algorithm is shown (default : 0).

HT :

output matrix (MxN matrix).

'plot':

when called with the additional string 'plot', htl displays HT using mesh.

RHO :

sequence of samples along the radial axis.

THETA :

sequence of samples along the azimutal axis.

Description

From an image IM, computes the integration of the values of the image over all the lines. The lines are parametrized using polar coordinates. The origin of the coordinates is fixed at the center of the image, and theta is the angle between the VERTICAL axis and the perpendicular (to the line) passing through the origin. Only the values of IM exceeding 5 // of the maximum are taken into account (to speed up the algorithm).

Examples

N=64; t=(1:N); y=fmlin(N,0.1,0.3);
IM=tfrwv(y,t,N); grayplot(t,y,IM'); scf(); htl(IM,N,N,1,'plot');

Authors

<< holder Post-Processing or Help to the Interpretation margtfr >>