CURVATURE(1)

NAME
curvature - curvature of a contour

SYNOPSIS
K = curvature(BW [,sigma])
K = curvature(x,y [,sigma])

PARAMETERS

K   vector containing the curvature of the contour at each point.

BW  Binary image containing only one object (0 for background, 1 for object).

x and y
    vectors, storing the parametrized contour.

sigma
    standard deviation of the gaussian function used to smooth the contour before computing the curvature. Defaults to 5.

DESCRIPTION
Function curvature calculates the curvature at each point of a binary contour, using FFT and a formula from differential geometry.

EXAMPLE
initial_dir = PWD;
chdir (SIPDIR + 'examples');
Img = imread('star.bmp');
xbasc()
imshow(Img,2);
k = curvature(Img,13);
xbasc()
plot(k)
//
// observe there are six curvature peaks,
// corresponding to the six peaks of the star. There
// is one peak half at 0 and half at about 1450.
// Thats because the parametrization of
// the contour started at the highest peak and
// terminated there.
//
chdir(initial_dir);

REFERENCES
"Shape Analysis and Classification", L. da F. Costa and R. M Cesar Jr., CRC Press, pp. 335-347.

"Differential Geometry of Curves and Surfaces", Manfredo P. do Carmo, Prentice Hall, 1976.

AUTHORS
Ricardo Fabbri <rfabbri@if.sc.usp.br>

AVAILABILITY
The latest version of the Scilab Image Processing toolbox can be found at

    http://cyvision.if.sc.usp.br/~rfabbri/sip/

SEE ALSO
follow, gsm, fftderiv