www.pudn.com > new_SPIHT.rar > func_SPIHT_Main.m

function func_SPIHT_Main 
% Matlab implementation of SPIHT (without Arithmatic coding stage) 
% 
% Main function  
% 
% input:    Orig_I : the original image. 
%           rate : bits per pixel 
% output:   img_spiht  
% 
% Jing Tian 
% Contact me : scuteejtian@hotmail.com 
% This program is part of my undergraduate project in GuangZhou, P. R. China. 
% April - July 1999 
 
%-----------   Input   ---------------- 
%I=imread('3668.tif');I1=I(1:512,1:512); 
%X=mat2gray(I1); 
load wbarb 
Orig_I = X; 
rate =0.80; 
 
%-----------   Pre-processing   ---------------- 
 
OrigSize = size(Orig_I, 1); 
max_bits = floor(rate * OrigSize^2); 
 
OutSize = OrigSize; 
image_spiht = zeros(size(Orig_I)); 
% "image " is the input of codec 
[nRow, nColumn] = size(Orig_I); 
 
 
%-----------   Wavelet Decomposition   ---------------- 
n = size(Orig_I,1); 
n_log = log2(n);  
level = n_log; 
% wavelet decomposition level can be defined by users manually. 
 
type = 'db4'; 
[Lo_D,Hi_D,Lo_R,Hi_R] = wfilters(type); 
 
[I_W, S] = func_DWT(Orig_I,3, Lo_D, Hi_D); 
 
%-----------   Coding   ---------------- 
img_enc = func_SPIHT_Enc(I_W, max_bits, nRow*nColumn,5);   
L=length(img_enc); 
%-----------   Decoding   ---------------- 
img_dec = func_SPIHT_Dec(img_enc); 
 
%-----------   Wavelet Reconstruction   ---------------- 
img_spiht = func_InvDWT(img_dec, S, Lo_R, Hi_R, 3); 
X0=img_spiht; 
%-----------   PSNR analysis   ---------------- 
Q = 255; 
%r=(16*256*256)/L 
MSE = sum(sum((img_spiht - Orig_I).^2))/( nRow * nColumn); 
psnr = 10*log10(Q*Q/MSE) 
%figure(1);imshow(X) 
figure(2);subplot(121);image(X0);colormap(map);title('SPITH Image'); 
subplot(122);image(X);colormap(map);title('origine image');