Distortionless Data Hiding.rar_data hiding_data hiding matlab_dw

% Distortionless data hiding based on integer wavelet transform (Watermark Embedding) % Guorong Xuan Jiang Zhu Jidong Chen Shi, Y.Q. Zhicheng Ni Wei Su % Department of Computer Science, Tongji University, Shanghai % % This paper appears in: Electronics Letters % Publication Date: 5 Dec 2002 % Volume: 38, Issue: 25 % On page(s): 1646- 1648 % ISSN: 0013-5194 % August 12, 2007, 4:37pm % updated August 19, 2007, 5:45pm % updated 13 December, 2008 % By: Asad (asad_82@yahoo.com) % NOTE: In case of error change the bit plane number as embedding may not be possible using that bitplane. % Also in order to achieve more bpp, bit plane number can be changed. clear all; close all; % define constants BITPLANE_NUMBER = 4; %4 % specifies the bitplane number to embedd watermark ERROR_NUM = 16; %16 % prevents this gray value from being used in embedding WM_SIZE = 300; % select the bitplane number and then the corresponding error num from the % table below % BITPLANE_NUMBER = [1 2 3 4 5 6 7 8] % ERROR_NUM = [128 64 32 16 8 4 2 1] disp('------------------------ Embedding -------------------------------'); % read image and convert to gray scale if necessary originalImage = imresize(imread('lena.tif'),[512 512],'bicubic'); if (isrgb(originalImage)) originalImage = rgb2gray(originalImage); end % STEP 1: perform necessary preprocessing %[valCount,X] = imhist(originalImage); % STEP 2: perfom wavelet decomposition LS = liftwave('cdf2.2','Int2Int'); [CA,CH,CV,CD] = lwt2(double(originalImage),LS); % STEP 3: construct binary images from 5th bit of CH, CV and CD for i=1:size(CH,1) for j=1:size(CH,2) % for constructing binary image using CH binSeq = dec2bin(abs(CH(i,j)),8); if binSeq(BITPLANE_NUMBER) == '1' bICH5(i,j) = 2; else bICH5(i,j) = 1; end % for constructing binary image using CV binSeq = dec2bin(abs(CV(i,j)),8); if binSeq(BITPLANE_NUMBER) == '1' bICV5(i,j) = 2; else bICV5(i,j) = 1; end % for constructing binary image using CD binSeq = dec2bin(abs(CD(i,j)),8); if binSeq(BITPLANE_NUMBER) == '1' bICD5(i,j) = 2; else bICD5(i,j) = 1; end end end % STEP 4a: Compress data in 5th Bit plane of CH % find how many times 1 occurs in the level 5 binary bICH5 (horizontal) [xx,yy,val] = find(bICH5 == 1); totalVals = size(CH,1)*size(CH,2); % code the sequence using arithmetic coding count1 = [round((size(xx,1)/totalVals)*100) round(((totalVals - size(xx,1))/totalVals) * 100)]; seq1 = reshape(bICH5,1,size(CH,1)*size(CH,2)); arcCH5 = arithenco(seq1,count1); str = sprintf('Original CH Bits Length = %d ------ Compressed CH Bits Length = %d',size(seq1,2),size(arcCH5,2)); disp(str); % STEP 4b: Compress data in 5th Bit plane of CV % find how many times 1 occurs in the level 5 binary bICV5 (vertical) [xx,yy,val] = find(bICV5 == 1); totalVals = size(CV,1)*size(CV,2); % code the sequence using arithmetic coding count2 = [round((size(xx,1)/totalVals)*100) round(((totalVals - size(xx,1))/totalVals) * 100)]; seq2 = reshape(bICV5,1,size(CV,1)*size(CV,2)); arcCV5 = arithenco(seq2,count2); str = sprintf('Original CV Bits Length = %d ------ Compressed CV Bits Length = %d',size(seq2,2),size(arcCV5,2)); disp(str); % STEP 4c: Compress data in 5th Bit plane of CD % find how many times 1 occurs in the level 5 binary bICD5 (diagonal) [xx,yy,val] = find(bICD5 == 1); totalVals = size(CD,1)*size(CD,2); % code the sequence using arithmetic coding count3 = [round((size(xx,1)/totalVals)*100) round(((totalVals - size(xx,1))/totalVals) * 100)]; seq3 = reshape(bICD5,1,size(CD,1)*size(CD,2)); arcCD5 = arithenco(seq3,count3); str = sprintf('Original CD Bits Length = %d ------ Compressed CD Bits Length = %d',size(seq3,2),size(arcCD5,2)); disp(str); % STEP 5: read the watermark and reshape it for insertion watermark = imresize(rgb2gray(imread('logo_im.jpg')),[WM_SIZE WM_SIZE],'bicubic'); %watermark = imresize(DMlcd5,[WM_SIZE WM_SIZE],'bicubic'); watermark = im2bw(watermark); %figure,imshow(watermark,[]),title('Watermark'); watermark = reshape(watermark,1,WM_SIZE*WM_SIZE); % STEP 6: Insert the watermark and compressed data into the image % compute length of data to insert dataLength = size(watermark,2) + size(arcCH5,2) + size(arcCV5,2) + size(arcCD5,2) + 6*8 + 4*16;%(2*8)*3; available = size(CH,1)*size(CH,2) + size(CV,1)*size(CV,2) + size(CD,1)*size(CD,2); if available < dataLength disp('Data to Embedd must be less than available limit.'); end % allocate memory and initialize embedData = zeros(1,dataLength); % insert the header information str1 = dec2bin(count1(1,1),8); str2 = dec2bin(count1(1,2),8); header = strcat(str1,str2); str1 = dec2bin(count2(1,1),8); str2 = dec2bin(count2(1,2),8); header = strcat(header,str1,str2); str1 = dec2bin(count3(1,1),8); str2 = dec2bin(count3(1,2),8); header = strcat(header,str1,str2); % insert length of each sequence for decoding str1 = dec2bin(size(arcCH5,2),16); str2 = dec2bin(size(arcCV5,2),16); str3 = dec2bin(size(arcCD5,2),16); str4 = dec2bin(size(watermark,2),32); header = strcat(header,str1,str2,str3,str4); for i=1:size(header,2) if header(1,i) == '1' embedData(1,i) = 1; else embedData(1,i) = 0; end end % get the header length HL = size(header,2); % concatenate data to get a single compressed data vector embedData(1,HL+1:HL+size(arcCH5,2)) = arcCH5(1,:); embedData(1,HL+size(arcCH5,2)+1:(HL+size(arcCH5,2) + size(arcCV5,2))) = arcCV5(1,:); embedData(1,HL+size(arcCH5,2)+ size(arcCV5,2)+1:(HL + size(arcCH5,2) + size(arcCV5,2) + size(arcCD5,2))) = arcCD5(1,:); embedData(1,HL+size(arcCH5,2)+ size(arcCV5,2)+size(arcCD5,2)+1:(HL+size(arcCH5,2) + size(arcCV5,2) + size(arcCD5,2)+ size(watermark,2))) = watermark(1,:); originalBitsLength = HL + size(arcCH5,2)+ size(arcCV5,2)+size(arcCD5,2); % embedd compressed data, watermark and header information index = 1; % counter for obtaining 8 bit chunks brk = 0; for x=1:size(CH,1) for y=1:size(CH,2) if CH(x,y) ~= -ERROR_NUM neg = 0; if CH(x,y) < 0 neg = 1; end binSeq = dec2bin(abs(CH(x,y)),8); if embedData(1,index) == 1 binSeq(BITPLANE_NUMBER) = '1'; else binSeq(BITPLANE_NUMBER) = '0'; end num = bin2dec(binSeq); if neg == 1 CH(x,y) = num * -1; else CH(x,y) = num; end % break the loop if all watermark bits are embedded if index < size(embedData,2) index = index + 1; else brk = 1; break; end end end if brk == 1 break; end end if index < size(embedData,2) for x=1:size(CV,1) for y=1:size(CV,2) if CV(x,y) ~= -ERROR_NUM neg = 0; if CV(x,y) < 0 neg = 1; end binSeq = dec2bin(abs(CV(x,y)),8); if embedData(1,index) == 1 binSeq(BITPLANE_NUMBER) = '1'; else binSeq(BITPLANE_NUMBER) = '0'; end num = bin2dec(binSeq); if neg == 1 CV(x,y) = num * -1; else CV(x,y) = num; end % break the loop if all watermark bits are embedded if index < size(embedData,2) index = index + 1; else brk = 1; break; end