图像压缩经典算法-LBG

function design() % create a codebook % sig--------image signal % re_sig--------reform image signal--fit to VQ % siz_word---the size of codeword % siz_book---the size of codebook % m_sig------the number of image matrix row % n_sig------the number of image matrix column figure(1); %调入和显示原始图像 sig=imread('11.bmp'); %求出图像象素的行数和列数 [m_sig,n_sig]=size(sig); %设置码字大小 siz_word=4; %设置码书大小 siz_book=512; if m_sig~=n_sig error('signal is not fitable for quantization.'); end if mod(m_sig,siz_word)~=0 error('signal is also not fitable for quantization.'); end imshow(sig); %将图像分割和变形 num=m_sig/siz_word;%32 ss=siz_word*siz_word;%64 nn=num*num;%1024 re_sig=[];%64,1024 %图像分块处理 for i=1:m_sig for j=1:m_sig f1=floor(i./siz_word); m1=mod(i,siz_word); if m1==0 m1=siz_word; f1=f1-1; end f2=floor(j./siz_word); m2=mod(j,siz_word); if m2==0 m2=siz_word; f2=f2-1; end re_sig(num*f1+f2+1,siz_word*(m1-1)+m2)=sig(i,j); end end % 码书初始化 codebook=[]; for i=1:siz_book r=floor(rand*nn); codebook=[codebook;re_sig(r,:)]; end % LBG 算法 sea=100; while sea<=0.0001 d1=0.0; for i=1:siz_book VectorNumber(i)=0; % the number of codeword of every class is 0 end for i=1:nn CodeNumber(i)=1; min=VectorDistance(siz_word,re_sig(i,:),codebook(1,:)); for j=2:siz_book d=0.0; for l=2:siz_word d=d+(re_sig(i,l)-codebook(j,l))^2; if d>=min break; end end if d<min min=d; CodeNumber(i)=j; end end VectorNumber(CodeNumber(i))=VectorNumber(CodeNumber(i))+1; d1=d1+min; end sea=(d0-d1)/d1; if sea<=0.0001 break; end d0=d1; for j=1:siz_book if VectorNumber[j]~=0 dd=zeros(1,siz_word); for l=1:nn if CodeNumber(l)==j for k=1:siz_word dd(k)=dd(k)+re_sig(l,k); end end end for k=1:siz_word codebook(j,k)=dd(k)/VectorNumber(j); end else msgbox('select a random vector'); l=floor(rand*nn); codebook(j,:)=re_sig(l,:); end end end save codebook4_512 codebook; %计算矢量距离的子函数 function z=VectorDistance(siz_word, Vector1, Vector2) for i=1:siz_word z=z+(Vector1(i)-Vector2(i))^2; end