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From: michael scheinfeild on 20 Feb 2010 03:52
hi i want to implement fourier descriptor of shape the problem i recive the shape
as original when reconstructed and cant have for round corners. if i use rectangle in back reconstruction i recive recuntungle without round corner
i use the
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
in case i use for rectangle d=2 , i recive first two points instead recive circle in back reconstruction. i use fft and ifft also i try to use the fftshift
here is my function
==============================
% image_edged is binary image 1,0 of border
% n size of fft
function [border_fft,border_restored]=make_fft(image_edged,n)

[a,b]=size(image_edged);
% finde indexes of edge
f=find(image_edged);
[ii,jj]=ind2sub(size(image_edged),f);
border_cmplx=ii+j*jj;
border_fft =(fft(border_cmplx,n)); % i try also fftshift(fft(... ?

border_ifft = (ifft(border_fft,n));% i try also length(f) ?
f=find(abs(border_ifft)>0.1);% im not sure here ....
rifftt=border_ifft(f);


border_restored = zeros(size(image_edged));
xx=real(rifftt);yy=imag(rifftt);


hind=sub2ind(size(border_restored),round(yy),round(xx));%here do i need the %round
border_restored(round(hind))=1;
===================
%here is how i call it[m is rectangle]
m=zeros(15);
m(4:8,4)=1;m(4:8,9)=1;
m(4,4:8)=1;m(9,4:9)=1;
figure,imshow(m)
border_fft,border_restored]=make_fft(m,32);% i try 1,2,4,8
% it behave starnge
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