fourier descriptor

shape description using FD fourier coeeficeients used for shape classification.
the steps :
1 . find the indexes borders of edged image (input binary edged image see test for example)
2. sort the indexes so they in distance order
3. make complex vecotr x+jy
4 make fft
5 take first FD
6. make ifft

currently the algorithm works for only symmetrical shapes !!!
i promise to improve it for all the shapes

link to theory :
http://www.tsi.enst.fr/tsi/enseignement/ressources/mti/descript_fourier/Part1.html

http://www.tsi.enst.fr/tsi/enseignement/ressources/mti/descript_fourier/Part2.html