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How to detect watermarking in DWT~ Include matlab source~ please help me~~

Asked by DoSeok Lee on 25 Jun 2015
Latest activity Edited by DoSeok Lee on 26 Jun 2015
how to detect watermarking??
I don't know how about detecting watermarking code
please help me!
I successed insert watermarking but I can't exctract watermark
clear all;
clc
% read gray image
gray_img = imread('body_1_gray256.jpg');
% convert double image
gray_img = double(gray_img);
init = 0.0001; %
%
[p q] = size(gray_img);
%
sign_img = imread('sign_image.jpg');
[Lo_D,Hi_D,Lo_R,Hi_R] = wfilters('haar');
[cA,cH,cV,cD] = dwt2(gray_img,Lo_D,Hi_D);
% watermarking start
y = [cA cH;cV cD];
Y = y + init*abs(y).* double(sign_img);
p=p/2;q=q/2;
for i=1:p
for j=1:q
ncA(i,j) = Y(i,j);
ncV(i,j) = Y(i+p,j);
ncH(i,j) = Y(i,j+q);
ncD(i,j) = Y(i+p,j+q);
end
end
Watermarked_img = idwt2(ncA,ncH,ncV,ncD,Lo_R,Hi_R);

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1 Answer

Answer by B.k Sumedha on 25 Jun 2015
 Accepted Answer

clc
close all
%host
rgbimage=imread('host.jpg');
figure;imshow(rgbimage);title('original color image');
[h_LL,h_LH,h_HL,h_HH]=dwt2(rgbimage,'haar');
dec2d = [...
h_LL, h_LH; ...
h_HL, h_HH ...
];
figure,imshow(uint8(dec2d));title('DWT2 of original color image');
%watermark
rgbimage=imread('watermark.jpg');
figure;imshow(rgbimage);title('Watermark image');
[w_LL,w_LH,w_HL,w_HH]=dwt2(rgbimage,'haar');
dec2d = [...
w_LL, w_LH; ...
w_HL, w_HH ...
];
figure,imshow(uint8(dec2d));title('DWT2 of Watermark image');
%watermarked
rgbimage=imread('watermarked.jpg');
figure;imshow(rgbimage);title('Watermarked image');
[wm_LL,wm_LH,wm_HL,wm_HH]=dwt2(rgbimage,'haar');
dec2d = [...
wm_LL, wm_LH; ...
wm_HL, wm_HH ...
];
figure,imshow(uint8(dec2d));title('DWT2 of Watermarked image');
%watermarking
newwatermark_LL= (wm_LL-h_LL)/0.30;
%extracted watermark image
rgb2=idwt2(newwatermark_LL,w_LH,w_HL,w_HH,'haar');
figure;imshow(uint8(rgb2));title('Extracted watermark');
imwrite(uint8(rgb2),'EWatermark.jpg');

  1 Comment

Hi~ B.k Sumedha thank you for my Question But I wonder your matlab source~
%host rgbimage=imread('host.jpg');%<-- example cameraman.tif (my file name)256x256
%watermark rgbimage=imread('watermark.jpg'); %<-- exmaple rice.tif (my file name)256x256
%watermarked rgbimage=imread('watermarked.jpg'); <-- I don't know what image insert?

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