MATLAB程序-信源编码

1、计算信源熵的MATLAB源程序function H=entropy(P,r) if (length(find(P<=0)=0) error('Not a prob.vector,negative component'); end if(abs(sum(P)-1)>10e-10) error('Not a prob.vector,component do not add up to 1'); end H=(sum(-P.*log2(P)/(log2(r)+eps);香农编码的MATLAB源程序function s,L,q=shannon(p)%if(l

2、ength(find(p<=0)=0) % error('Not a prob.vector,negative component');%end%if(abs(sum(p)-1)>10e-10) % error('Not a prob.vector,component do not add up to 1')%endn=length(p);x=1:n;p,x=array(p,x);l=ceil(-log2(p);P(1)=0;n=length(p);for i=2:n P(i)=P(i-1)+p(i-1);endfor i=1:n for j=1:l

3、(i) temp(i,j)=floor(P(i)*2); P(i)=P(i)*2-temp(i,j); endends=;for i=1:n for j=1:l(i) t=temp(i,j); % if(temp(i,j)=0) % W(i,j)=48; s=s num2str(t); %else %W(i,j)=49; % end end s=s ' 'endL=sum(p.*l);H=entropy(p,2);q=H/L;for i=1:n Bi=i;ends0='很好！输入正确，编码结果如下:'s1='Shannon 编码所得码字W:'s2

4、='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functionW,L,q=fano(P)if(length(find(P<=0)=0) error('Not a prob.vector,negative component');endif(abs(sum(P)-1)>10e-10) error('Not a prob.vect

5、or,component do not add up to 1');endn=length(P);x=1:n;P,x=array(P,x);for i=1:n current_index=i; j=1; current_P=P; while 1 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; end end l(i)=

6、length(find(abs(W(i,:)=0);endL=sum(P.*l);H=entropy(P,2);q=H/L;for i=1:n Bi=i;endn,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

7、(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('Not a prob.vector,negative component');endif(abs(sum(P)-1)>10e-10) error('Not a prob.vector,component do not add up to 1');endn=length(P);p=P;m

8、ark=zeros(n-1,n);for i=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;endfor i=1:n-1 table(i,:)=blanks(n*n);endtable(n-1,n)='1'table(n-1,2*n)='0'for i=2:n-1 table(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

9、,n)='1' table(n-i,n+1:2*n-1)=table(n-i,1:n-1); table(n-i,2*n)='0' for j=1:i-1 table(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); endend for i=1:n W(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); end L=sum(P.*l); H=entropy(P,2); q=H/L; for i=1:n Bi=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