SIP Toolbox

curvature - Curvature of a contour

Calling Sequence

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

Parameters

Description

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

Examples

       initial_dir = PWD;
       chdir (SIPDIR + 'images');

       Img = imread('star.bmp');
       xbasc()
       imshow(Img,2);
       k = curvature(Img,13);  // 13 sigma (shape is smoothed so curvature exists)
       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 450.
       // That's because the parametrization of
       // the contour started at the highest peak and
       // terminated there. Note also that the shape had to
       // be considerably smoothed so the curvature doesn't
       // blow up at the very sharp peaks of the star.
       //

       chdir(initial_dir);
   

Authors

Ricardo Fabbri <ricardofabbri (AT) users DOT sf DOT net>

Bibliography

"Shape Analysis and Classification", L. da F. Costa and R. M. Cesar Jr., CRC Press.

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

Availability

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

http://siptoolbox.sourceforge.net

See Also

follow,  gsm,  fftderiv,