lsb嵌入水印代码

%Name:ChrisShoemaker
%Course:EER-280-DigitalWatermarking
%Project:LeastSignificantBitSubstitution
%WatermarkEmbeding

clearall;

%savestarttime
start_time=cputime;

%readinthecoverobject
file_name='_lena_std_bw.bmp';
[cover_object,map]=imread(file_name);

%readinthemessageimage
file_name='key.bmp';
[message,map1]=imread(file_name);
message1=message;

%converttodoublefornormalization,thenbackagain
message=double(message);
message=fix(message./2);
message=uint8(message);

%determinesizeofcoverobject
Mc=size(cover_object,1);%Height
Nc=size(cover_object,2);%Width

%determinesizeofmessageobject
Mm=size(message,1);%Height
Nm=size(message,2);%Width

%titlethemessageobjectouttocoverobjectsizetogeneratewatermark
forii=1:Mc
forjj=1:Nc
watermark(ii,jj)=message(mod(ii,Mm)+1,mod(jj,Nm)+1);
end
end

%nowwesetthelsbofcover_object(ii,jj)tothevalueofwatermark(ii,jj)
watermarked_image=cover_object;
forii=1:Mc
forjj=1:Nc
watermarked_image(ii,jj)=bitset(watermarked_image(ii,jj),1,watermark(ii,jj));
end
end

%writethewatermarkedimageouttoafile
imwrite(watermarked_image,'lsb_watermarked.bmp','bmp');

%displayprocessingtime
elapsed_time=cputime-start_time,

%calculatethePSNR
psnr=psnr(cover_object,watermarked_image,Mc,Nc),

%displaywatermarkedimage
figure(1)
imshow(watermarked_image,[])
title('WatermarkedImage')
figure(2)
imshow(cover_object,[])
title('originalimage')
forii=1:Mc
forjj=1:Nc
watermark1(ii,jj)=message1(mod(ii,Mm)+1,mod(jj,Nm)+1);
end
end
%watermark1=watermark1*256;
%message1=message1*256;
figure(3)
imshow(watermark1,[])
title('thewatermark')
figure(4)
imshow(message1,[])
title('thewatermark')