%Image compression for color images
clear all;
close all;
clc;
% Reading an image file
[imagefile1 , pathname]= uigetfile('*.bmp;*.BMP;*.tif;*.TIF;*.jpg','Open An image');
if imagefile1 ~= 0
cd(pathname);
I=imread(char(imagefile1));
end;
X=I;
% inputting the decomposition level and name of the wavelet
n=input('Enter the decomposition level:');
wname = 'haar';
x = double(X);
TotalColors = 255;
map = gray(TotalColors);
x = uint8(x);
%Conversion of RGB to Grayscale
x = double(X);
xrgb = 0.2990*x(:,:,1) + 0.5870*x(:,:,2) + 0.1140*x(:,:,3);
colors = 255;
x = wcodemat(xrgb,colors);
map = pink(colors);
x = uint8(x);
% A wavelet decomposition of the image
[c,s] = wavedec2(x,n,wname);
% wdcbm2 for selecting level dependent thresholds
alpha = 1.5; m = 2.7*prod(s(1,:));
[thr,nkeep] = wdcbm2(c,s,alpha,m)
% Compression
[xd,cxd,sxd,perf0,perfl2] = wdencmp('lvd',c,s,wname,n,thr,'h');
disp('Compression Ratio');
disp(perf0);
% Decompression
R = waverec2(c,s,wname);
rc = uint8(R);
% Plot original and compressed images.
subplot(221), image(x);
colormap(map);
title('Original image')
subplot(222), image(xd);
colormap(map);
title('Compressed image')
% Displaying the results
xlab1 = ['2-norm rec.: ',num2str(perfl2)];
xlab2 = [' % -- zero cfs: ',num2str(perf0), ' %'];
xlabel([xlab1 xlab2]);
subplot(223), image(rc);
colormap(map);
title('Reconstructed image');
%Computing the image size
disp('Original Image');
imwrite(x,'original.tif');
imfinfo('original.tif')
disp('Compressed Image');
imwrite(xd,'compressed.tif');
imfinfo('compressed.tif')
disp('Decompressed Image');
imwrite(rc,'decompressed.tif');
imfinfo('decompressed.tif')
