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Chtl

Hough transform for detection of lines in images

Calling Sequence

[HT,RHO,THETA] = Chtl(IM)
[HT,RHO,THETA] = Chtl(IM, M)
[HT,RHO,THETA] = Chtl(IM, M, N)

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).

HT :

output matrix (MxN matrix).

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.

Examples

x = hilbert(sin(2*%pi*0.25*(1:128))+0.5*rand(1,128,'normal'));
tfr = Ctfrwv(x);
[HT,RHO,THETA] = Chtl(tfr);
grayplot(THETA, RHO, HT');
xlabel theta
ylabel rho

See also

Authors


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