ezw的Matlab程序

% This is a test program that tests the EZW % matrix X is an example matrix same as Shapiro's paper given X=[63 -34 49 10 7 13 -12 7; -31 23 14 -13 3 4 6 -1; 15 14 3 -12 5 -7 3 9; -9 -7 -14 8 4 -2 3 2; -5 9 -1 47 4 6 -2 2; 3 0 -3 2 3 -2 0 4; 2 -3 6 -4 3 6 3 6; 5 11 5 6 0 3 -4 4]; X0=X; Y0=max(X); Y1=max(Y0); for i=0:12; if 2^i<Y1 & 2^i>0.5*Y1; threshold=2^i; % get initial threshold T0; break; end; end; sublist=[]; [xx,yy]=size(X); global N A=mapping(xx); [m,n]=size(A); k=1; N=[]; for k=1:m*n; flag=0; for i=1:m; if flag==1; break; end for j=1:n; if A(i,j)==k; N=[N;i,j]; flag=1; break; end end end end order=1; while threshold ~= 0.5, % if threshold~=1, do dominantpass and subordinatepass. threshold %Dominant Pass [D,X,sublist] = dominantpass(X,threshold,sublist); DD{order}=D %Subordinate pass threshold=threshold/2; if threshold ==0.5, break; end S = subordinatepass(sublist,threshold); SS{order}=S order=order+1; end % EZW decoder global N; [m,n]=size(N);% the size of initial image % m is the pixels of initial image XX=zeros(8); % initialize the reconstructured image to zero; initialthreshold=32; threshold=initialthreshold; % initial theshold ; sublist=[]; % sublist is the new position matrix % for all significant coefficients 'p' and 'n'; for k=1:6; % laststeplevel=6; RR=zeros(8); % reference matrix RR; [a,b]=size(DD{k}); % ? % dominant pass i=1; j=1; while i<=m; if j>b; % b is the length of dominant pass vector break; end if RR(N(i,1),N(i,2))==1; i=i+1; else if DD{k}(j)=='p'; XX(N(i,1),N(i,2))=threshold; RR(N(i,1),N(i,2))=1; %reference matrix =1; sublist=[sublist;N(i,1),N(i,2)]; end if DD{k}(j)=='n'; XX(N(i,1),N(i,2))=-threshold; RR(N(i,1),N(i,2))=1; %reference matrix =1; sublist=[sublist;N(i,1),N(i,2)]; end if DD{k}(j)=='z'; RR(N(i,1),N(i,2))=1; %reference matrix =1; end if DD{k}(j)=='t'; RR(N(i,1),N(i,2))=1; %reference matrix =1; RR=checkchildren(i,RR);% all zerotree's descendants are set to 1. end i=i+1;j=j+1; end end % subordinate pass %[xx,yy]=size(s{k}); [xx,yy]=size(sublist); threshold=threshold/2; for i=1:xx; if k==6 |threshold==0.5; break; end if SS{k}(i)==1; if XX(sublist(i,1),sublist(i,2))>0; XX(sublist(i,1),sublist(i,2))= XX(sublist(i,1),sublist(i,2))+ threshold; else XX(sublist(i,1),sublist(i,2))= XX(sublist(i,1),sublist(i,2))-threshold; end end end threshold k XX end initialiamge=X0 reconstructuredimage=XX difference=XX-X0