i have written a code to hide a grayscale image within a rgb image.but while decrypting.the rgb image is retrieved.but the grayscale image is not.a black image is displayed instead.
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chaithra
le 28 Jan 2014
Commenté : Soumyaa Ghosal
le 25 Avr 2017
%/encryption
p=imread('flower.jpg');
q=imread('msgimage.jpg');
p1=rgb2gray(p)
s=size(q);
[r c]=size(p1);
figure(1),imshow(q),title('original');
q2=imresize(q,[r c]);
qr=q2(:,:,1);
qg=q2(:,:,2);
qb=q2(:,:,3);
l=r*c;
qr=bitand(qr,uint8(240));
p2=bitshift(p1,-3);
im=bitor(qr,p2);
im=cat(3,qr,qg,qb);
%im1=imresize(im1,[s(1) s(2)]);
figure(2),imshow(p1);
figure(3),imshow(im),title('final');
=========================================
%/decryption
ir=im(:,:,1);
ig=im(:,:,2);
ib=im(:,:,3);
x=bitand(ir,uint8(240));
y=bitand(ir,uint8(15));
x=cat(3,ir,ig,ib);
figure(1),imshow(x);
figure(2),imshow(y);
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Walter Roberson
le 28 Jan 2014
You have
im=bitor(qr,p2);
im=cat(3,qr,qg,qb);
which calculates im and then throws away that result and writes in a new one.
Plus de réponses (1)
Shivaputra Narke
le 28 Jan 2014
Modifié(e) : Walter Roberson
le 28 Jan 2014
Use following code...
Compare code and find the changes done.
Hope this help..
%/encryption
p=imread('flowers.jpg');
q=imread('msgimage.jpg');
p1=rgb2gray(p)
s=size(q);
[r c]=size(p1);
figure(1),imshow(q),title('original');
q2=imresize(q,[r c]);
qr=q2(:,:,1);
qg=q2(:,:,2);
qb=q2(:,:,3);
l=r*c;
qr=bitand(qr,uint8(240));
p2=bitshift(p1,-3);
im=bitor(qr,p2);
im=cat(3,im,qg,qb);
%im1=imresize(im1,[s(1) s(2)]);
figure(2),imshow(p1);
figure(3),imshow(im),title('final');
%/decryption
ir=im(:,:,1);
ig=im(:,:,2);
ib=im(:,:,3);
x=bitand(ir,uint8(240));
y=bitand(ir,uint8(15));
x=cat(3,ir,ig,ib);
figure(1),imshow(x);
figure(2),imshow(y,[]);
2 commentaires
Soumyaa Ghosal
le 25 Avr 2017
Can you please tell me which method of steganography is this ? Is this LSB or some other method ? Thanks in advance.
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