MATLAB程序-信源编码

计算信源熵的MATLAB源程序functionH=entropy(P,r)if(length(find(P=0))~=0)error('Notaprob.vector,negativecomponent');endif(abs(sum(P)-1)10e-10)error('Notaprob.vector,componentdonotaddupto1');endH=(sum(-P.*log2(P)))/(log2(r)+eps);香农编码的MATLAB源程序function[s,L,q]=shannon(p)%if(length(find(p=0))~=0)%error('Notaprob.vector,negativecomponent');%end%if(abs(sum(p)-1)10e-10)%error('Notaprob.vector,componentdonotaddupto1')%endn=length(p);x=1:n;[p,x]=array(p,x);l=ceil(-log2(p));P(1)=0;n=length(p);fori=2:nP(i)=P(i-1)+p(i-1);endfori=1:nforj=1:l(i)temp(i,j)=floor(P(i)*2);P(i)=P(i)*2-temp(i,j);endends=[];fori=1:nforj=1:l(i)t=temp(i,j);%if(temp(i,j)==0)%W(i,j)=48;s=[snum2str(t)];%else%W(i,j)=49;%endends=[s''];endL=sum(p.*l);H=entropy(p,2);q=H/L;fori=1:nB{i}=i;ends0='很好！输入正确，编码结果如下:';s1='Shannon编码所得码字W:';s2='Shannon编码平均码字长度L:';s3='Shannon编码的编码效率q:';disp(s0);disp(s1),disp(B),disp(s);disp(s2),disp(L);disp(s3),disp(q);费诺编码的MATLAB源程序function[W,L,q]=fano(P)if(length(find(P=0))~=0)error('Notaprob.vector,negativecomponent');endif(abs(sum(P)-1)10e-10)error('Notaprob.vector,componentdonotaddupto1');endn=length(P);x=1:n;[P,x]=array(P,x);fori=1:ncurrent_index=i;j=1;current_P=P;while1[next_P,code_num,next_index]=compare(current_P,current_index);current_index=next_index;current_P=next_P;W(i,j)=code_num;j=j+1;if(length(current_P)==1)break;endendl(i)=length(find(abs(W(i,:))~=0));endL=sum(P.*l);H=entropy(P,2);q=H/L;fori=1:nB{i}=i;end[n,m]=size(W);TEMP=32*ones(n,5);W=[W,TEMP];W=W';[n,m]=size(W);W=reshape(W,1,n*m);W=sprintf('%s',W);s0='很好！输入正确，编码结果如下:';s1='Fano编码所得码字W:';s2='Fano编码平均码字长度L:';s3='Fano编码的编码效率q:';disp(s0);disp(s1),disp(B),disp(W);disp(s2),disp(L);disp(s3),disp(q);霍夫曼编码的MATLAB源程序function[W,L,q]=huffman(P)if(length(find(P=0))~=0)error('Notaprob.vector,negativecomponent');endif(abs(sum(P)-1)10e-10)error('Notaprob.vector,componentdonotaddupto1');endn=length(P);p=P;mark=zeros(n-1,n);fori=1:n-1[p,num]=sort(p);mark(i,:)=[num(1:n-i+1),zeros(1,i-1)];p=[p(1)+p(2),p(3:n),1];endfori=1:n-1table(i,:)=blanks(n*n);endtable(n-1,n)='1';table(n-1,2*n)='0';fori=2:n-1table(n-i,1:n-1)=table(n-i+1,n*(find(mark(n-i+1,:)==1))-(n-2):n*(find(mark(n-i+1,:)==1)));table(n-i,n)='1';table(n-i,n+1:2*n-1)=table(n-i,1:n-1);table(n-i,2*n)='0';forj=1:i-1table(n-i,(j+1)*n+1:(j+2)*n)=table(n-i+1,n*(find(mark(n-i+1,:)==j+1)-1)+1:n*find(mark(n-i+1,:)==j+1));endendfori=1:nW(i,1:n)=table(1,n*(find(mark(1,:)==i)-1)+1:find(mark(1,:)==i)*n);l(i)=length(find(abs(W(i,:))~=32));endL=sum(P.*l);H=entropy(P,2);q=H/L;fori=1:nB{i}=i;end;[m,n]=size(W);W=reshape(W',1,m*n);s0='很好！输入正确，编码结果如下：';s1='Huffman编码所得码字W:';s2='Huffman编码的平均码字长度L:';s3='Huffman编码的编码效率q:';disp(s0);disp(s1),disp(B),disp(W);disp(s2),disp(L);disp(s3),disp(q);