This is a dct code on watermark embedding. Please fix it
1 view (last 30 days)
Show older comments
Lester
on 27 Feb 2013
Commented: Walter Roberson
on 2 Jul 2016
The error I'm encountering is this -->
Warning: Size vector should be a row vector with integer elements.
> In watermarkemb at 27
??? Index exceeds matrix dimensions.
Error in ==> watermarkemb at 36
dct_block=dct2(cover_object(x:x+blocksize-1,y:y+blocksize-1));
This is the code -->
clc;
clear all;
start_time=cputime;
k=50;
blocksize=8;
file_name='scene.jpg';
cover_object=double(rgb2gray(imread(file_name)));
Mc=size(cover_object,1);
Nc=size(cover_object,2);
max_message=Mc*Nc/(blocksize^2);
file_name='fishy.jpg';
message=double(rgb2gray(imread(file_name)));
Mm=size(message,1);
Nm=size(message,2);
message=round(reshape(message,Mm*Nm,1)./256);
if (length(message) > max_message)
error('Message too large to fit in Cover Object')
end
message_pad=ones(1,max_message);
message_pad(1:length(message))=message;
watermarked_image_r=cover_object;
x=1;
y=1;
for (kk = 1:length(message_pad))
dct_block=dct2(cover_object(y:y+blocksize-1,x:x+blocksize-1));
if (message_pad(kk) == 0)
if (dct_block(5,2) < dct_block(4,3))
temp=dct_block(4,3);
dct_block(4,3)=dct_block(5,2);
dct_block(5,2)=temp;
end
elseif (message_pad(kk) == 1)
if (dct_block(5,2) >= dct_block(4,3))
temp=dct_block(4,3);
dct_block(4,3)=dct_block(5,2);
dct_block(5,2)=temp;
end
end
if dct_block(5,2) > dct_block(4,3)
if dct_block(5,2) - dct_block(4,3) < k
dct_block(5,2)=dct_block(5,2)+(k/2);
dct_block(4,3)=dct_block(4,3)-(k/2);
end
else
if dct_block(4,3) - dct_block(5,2) < k
dct_block(4,3)=dct_block(4,3)+(k/2);
dct_block(5,2)=dct_block(5,2)-(k/2);
end
end
watermarked_image(y:y+blocksize-1,x:x+blocksize-1)=idct2(dct_block);
if (x+blocksize) >= Nc
x=1;
y=y+blocksize;
else
x=x+blocksize;
end
end
watermarked_image_int=uint8(watermarked_image);
imwrite(watermarked_image_int,'dct1_watermarked_circuit.jpg','jpg');
elapsed_time=cputime-start_time,
subplot(211);imshow(cover_object,[]);title('Original Image')
subplot(212);imshow(watermarked_image,[]);title('Watermarked Image')
0 Comments
Accepted Answer
More Answers (1)
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Products
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!