testgenlloyd.m

Sparse Signal Representation using Overlapping Frames (matlab toolbox)

% TestGenLloyd  Test of the function GenLloyd 

%----------------------------------------------------------------------
% Copyright (c) 2002.  Karl Skretting.  All rights reserved.
% Hogskolen in Stavanger (Stavanger University), Signal Processing Group
% Mail:  [e-mail]   Homepage:  http://www.ux.his.no/~karlsk/
% 
% HISTORY:  dd.mm.yyyy
% Ver. 1.0  26.11.2002  KS: function made
%----------------------------------------------------------------------

clear all;
Mfile='TestGenLloyd';

L=100;
X=randn(2,L);
X(:,(floor(L/2)+1):L)=2+X(:,(floor(L/2)+1):L);
F=GenLloyd(X,6,0);
figure(1);clf;
plot(X(1,:),X(2,:),'b.');hold on;
plot(F(1,:),F(2,:),'r*');
% 
for j=1:L; 
    x=X(:,j); 
    temp=x'*x;
    if (temp==0); temp=1; else temp=sqrt(temp); end;
    if (sum(x)<0); temp=-temp; end;
    X(:,j)=x/temp; 
end
F=GenLloyd(X,4,1);
figure(1);clf;
plot(X(1,:),X(2,:),'b.');hold on;
plot(F(1,:),F(2,:),'r*');


% a larger test
L=5000;K=40;N=25;
TextureFile = 'C:\Karl\FraWWW\Bilder\Textures\D5D92_1.BMP';  % an image
X=imread(TextureFile);
[Mx,Nx,Cx]=size(X);
if (Cx==3)     
    X=rgb2gray(X);Cx=1;
    disp([Mfile,': make grayscale image of color image.']);
end
B=double(X);
[X,H2]=SetFfromImage(B,L,[5,5]);     % this picks blocks form B into X and normalize X
F=GenLloyd(X,K,1);    
n1=13;
for n2=1:N
    if (n2~=n1)
        figure(1);clf;
        plot(X(n1,:),X(n2,:),'b.');hold on;
        plot(F(n1,:),F(n2,:),'r*');
        xlabel(['coordinate number ',int2str(n1)]);
        ylabel(['coordinate number ',int2str(n2)]);
        pause;
    end
end
% and not normalized, this takes much longer time
X=X-0.2;
F=GenLloyd(X(:,1:(L/10)),10,0);    % do not use all in initialization
F=GenLloyd(X,F,0);