RGB=imread('droga.jpg') ;
N=3;
I=rgb2gray(RGB);
I=double(I);
step=32;
partition = [step:step:256];
r = [0:step:256];
[m,n] = size(I);
quant=[m,n];
mf=floor(m/N);
nf=floor(n/N);
for k=0:N-1
for j=0:N-1
    frag=I(mf*k+1:mf*(k+1),nf*j+1:nf*(j+1));
    %imshow(frag);
    frag = reshape(frag,mf*nf,1);
    min=10000;
    res=1:9;
    for i=1:11
        [partition, codebook] = lloyds (frag,r);
        [index,frag2,distor] = quantiz(frag,partition, codebook);
        res(i) = distor;
        if distor<min
            min=distor;
            bestP=partition;
            bestC=codebook;
            bestR=r;
        end
        r =[0:step:256];
        r=round(sort(randn(1,9)*step+r));
    end
    [index,frag,distor]=quantiz(frag,bestP,bestC);
    frag=uint8(reshape(frag,mf,nf));
    quant(mf*k+1:mf*(k+1),nf*j+1:nf*(j+1))=frag;
end
end
quant=uint8(reshape(quant,mf*N,nf*N));
imshow(quant);