DCT.rar_image hiding matlab_image steganography_it_steganography

%%% This program hides an image into the original by the algorithm clear; clc; img=double(imread('lena.bmp'));%% Read the original [row col]=size(img); sec=double(imread('images.jpg'));%% Read the secret image %%Standard quantization table qTable=[16 11 10 16 24 40 51 61; 12 12 14 19 26 58 60 55; 14 13 16 24 40 57 69 56; 14 17 22 29 51 87 80 62; 18 22 37 56 68 109 103 77; 24 35 55 64 81 104 113 92; 49 64 78 87 103 121 120 101; 72 92 95 98 112 100 103 99]; nimg=zeros(row,col); mrec=zeros(row/8,col/8); rec=zeros(row/8,col/8); th=175; correct=0; %ptr=1; for m=1:row/8 for n=1:col/8 s1=img((m-1)*8+1:m*8,(n-1)*8+1:n*8); d1=dct2(s1); %u=A(:,:,j,k)-128; %v=a*u*a'; q1=floor(d1./qTable+0.5); if sec(m,n)>th mark=1; else mark=0; end; w1=embed(q1,mark); r1=w1.*qTable; k1=idct2(r1); nimg((m-1)*8+1:m*8,(n-1)*8+1:n*8)=k1; end; end; %mse=mean(mean((nimg-img).^2)); %psnr=10*log10(255*255/mse) %calculation [PSNR_OUT,Z] = psnr(img,nimg); str = sprintf('PSNR = %f',PSNR_OUT); disp(str); %I0 = double(img); %I1 = double(nimg); %Id = (I0-I1); %signal = sum(sum(I0.^2)); %noise = sum(sum(Id.^2)); %SNR = 10*log10(signal/noise); %disp('SNR Signal to Noise Ratio'); %disp(SNR); %MSE = noise/numel(I0); %peak = max(I0(:)); %PSNR = 10*log10(peak^2/MSE); %disp('PSNR Peak Signal to Noise Ratio'); %disp(PSNR); %show subplot(1,3,1) imshow(uint8(img)) title('Cover image') subplot(1,3,2) imshow(uint8(sec)) title('Secret image') subplot(1,3,3) imshow(nimg,[]) %AutoImage(nimg) title('Stego image') imwrite(uint8(round(nimg)),'Stego image.jpg');