www.pudn.com > SPIHT_bandelet.rar > func_InvDWT.m

function im_rec = func_InvDWT(I_W, S, Lo_R, Hi_R, level); 
% Matlab implementation of SPIHT (without Arithmatic coding stage) 
% 
% Inverse wavelet decomposition 
% 
% input:    I_W : decomposed image vector 
%           S : corresponding bookkeeping matrix 
%           Lo_D : low-pass decomposition filter 
%           Hi_D : high-pass decomposition filter 
%           level : wavelet decomposition level 
% 
% output:   im_rec : reconstruted image 
% 
% Jing Tian 
% Contact me : scuteejtian@hotmail.com 
% This program is part of my undergraduate project in GuangZhou, P. R. China. 
% April - July 1999 
 
L = length(S); 
 
m = I_W; 
 
C1 = zeros(1,S(1,3)+3*sum(S(2:L-1,3))); 
 
% approx part 
C1(1:S(1,3)) = reshape( m( 1:S(1,1) , 1:S(1,2) ), 1 , S(1,3) ); 
 
for k = 2:L-1 
    rows = [sum(S(1:k-1,1))+1:sum(S(1:k,1))]; 
    columns = [sum(S(1:k-1,2))+1:sum(S(1:k,2))]; 
    % horizontal part 
    c_start = S(1,3) + 3*sum(S(2:k-1,3)) + 1; 
    c_stop = S(1,3) + 3*sum(S(2:k-1,3)) + S(k,3); 
    C1(c_start:c_stop) = reshape( m( 1:S(k,1) , columns ) , 1, c_stop-c_start+1); 
    % vertical part 
    c_start = S(1,3) + 3*sum(S(2:k-1,3)) + S(k,3) + 1; 
    c_stop = S(1,3) + 3*sum(S(2:k-1,3)) + 2*S(k,3); 
    C1(c_start:c_stop) = reshape( m( rows , 1:S(k,2) ) , 1 , c_stop-c_start+1 ); 
    % diagonal part 
    c_start = S(1,3) + 3*sum(S(2:k-1,3)) + 2*S(k,3) + 1; 
    c_stop = S(1,3) + 3*sum(S(2:k,3)); 
    C1(c_start:c_stop) = reshape( m( rows , columns ) , 1 , c_stop-c_start+1); 
end 
 
if (( L - 2) > level)   %set those coef. in higher scale to 0 
    temp = zeros(1, length(C1) - (S(1,3)+3*sum(S(2:(level+1),3)))); 
    C1(S((level+2),3)+1 : length(C1)) = temp; 
end 
 
S(:,3) = []; 
 
im_rec = func_Mywaverec2(C1,S, Lo_R, Hi_R);