digital image watermarking. using DWT

Question

TJ Singh 2012-3-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/33322-digital-image-watermarking-using-dwt

评论： meziane madani 2017-5-19

I'm working in digital image watermarking. I've found DWT matlab code on internet, but it can't give proper results. plz debug it, so that it works properly.

% Watermark Embeding
clear all;
 % save start time
start_time=cputime;
 k=2;            % set the gain factor for embeding
 % read in the cover object
file_name='_lena_std_bw.bmp';
cover_object=double(imread(file_name));
 % determine size of watermarked image
Mc=size(cover_object,1);    %Height
Nc=size(cover_object,2);    %Width
 % read in the message image and reshape it into a vector
file_name='_copyright.bmp';
message=double(imread(file_name));
Mm=size(message,1);                         %Height
Nm=size(message,2);                         %Width
message_vector=round(reshape(message,Mm*Nm,1)./256);
[cA1,cH1,cV1,cD1] = dwt2(cover_object,'haar');
 % add pn sequences to H1 and V1 componants when message = 0 
for (kk=1:length(message_vector))
    pn_sequence_h=round(2*(rand(Mc/2,Nc/2)-0.5));
    pn_sequence_v=round(2*(rand(Mc/2,Nc/2)-0.5));
       if (message(kk) == 0)
        cH1=cH1+k*pn_sequence_h;
        cV1=cV1+k*pn_sequence_v;
    end
end
 % perform IDWT
watermarked_image = idwt2(cA1,cH1,cV1,cD1,'haar',[Mc,Nc]); 
 % convert back to uint8
watermarked_image_uint8=uint8(watermarked_image);
 % write watermarked Image to file
imwrite(watermarked_image_uint8,'dwt_watermarked.bmp','bmp');
 % display processing time
elapsed_time=cputime-start_time,
% display watermarked image
figure(1)
imshow(watermarked_image_uint8,[])
title('Watermarked Image')
% Watermark Recovery
clear all;
% save start time
start_time=cputime;
% read in the watermarked object
file_name='dwt_watermarked.bmp';
watermarked_image=double(imread(file_name));
% determine size of watermarked image
Mw=size(watermarked_image,1);           %Height
Nw=size(watermarked_image,2);           %Width
% read in original watermark
file_name='_copyright.bmp';
orig_watermark=double(imread(file_name));
% determine size of original watermark
Mo=size(orig_watermark,1);  %Height
No=size(orig_watermark,2);  %Width
 % initalize message to all ones
message_vector=ones(1,Mo*No);
 [cA1,cH1,cV1,cD1] = dwt2(watermarked_image,'haar');
 % add pn sequences to H1 and V1 componants when message = 0 
for (kk=1:length(message_vector))
    pn_sequence_h=round(2*(rand(Mw/2,Nw/2)-0.5));
    pn_sequence_v=round(2*(rand(Mw/2,Nw/2)-0.5));
       correlation_h(kk)=corr2(cH1,pn_sequence_h);
    correlation_v(kk)=corr2(cV1,pn_sequence_v);
    correlation(kk)=(correlation_h(kk)+correlation_v(kk))/2;
end
 for (kk=1:length(message_vector))
    if (correlation(kk) > mean(correlation))
        message_vector(kk)=0;
    end
end
 % reshape the message vector and display recovered watermark.
figure(2)
message=reshape(message_vector,Mo,No);
imshow(message,[])
title('Recovered Watermark')
 % display processing time
elapsed_time=cputime-start_time,

2 个评论
显示无隐藏无

DAVID KING 2016-1-17

编辑：DAVID KING 2016-1-17

If u have any query thn regarding ur project either mail at matlabprojects35@gmail.com or, https://www.facebook.com/MatlabProjects-909644652486619. Kindly Spread it to Help Others.

meziane madani 2017-5-19

hi, what is exectly your problem ?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Afroja Akter 2013-7-30

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/33322-digital-image-watermarking-using-dwt#answer_93098

could u give any code for evalution purpose like NC(NORMALISED CORRELATION),,also could u tell me why not i could not save ma image wchich has been embedded,,