THESE/codes/graphe/Ncut_9/doog1.m

   1 function H=doog1(sig,r,th,N);
   2 % H=doog1(sig,r,th,N);
   3 % Serge Belongie
   4
   5 no_pts=N;  % no. of points in x,y grid
   6
   7 [x,y]=meshgrid(-(N/2)+1/2:(N/2)-1/2,-(N/2)+1/2:(N/2)-1/2);
   8
   9 phi=pi*th/180;
  10 sigy=sig;
  11 sigx=r*sig;
  12 R=[cos(phi) -sin(phi); sin(phi) cos(phi)];
  13 C=R*diag([sigx,sigy])*R';
  14
  15 X=[x(:) y(:)];
  16
  17 Gb=gaussian(X,[0 0]',C);
  18 Gb=reshape(Gb,N,N);
  19
  20 m=R*[0 sig]';
  21
  22 a=1;
  23 b=-1;
  24
  25 % make odd-symmetric filter
  26 Ga=gaussian(X,m/2,C);
  27 Ga=reshape(Ga,N,N);
  28 Gb=rot90(Ga,2);
  29 H=a*Ga+b*Gb;
  30