数字内容安全LSB替换算法MATLAB实现.rar_lsb替换算法；MATLAB_matlab lsb 修改_serviceak

%Name: Chris Shoemaker %Course: EER-280 - Digital Watermarking %Project: Least Significant Bit Substitution % Watermark Recovery clc clear all close all %% save start time start_time=cputime; %% read in watermarked image file_name='lsb_watermarked.bmp'; %file_name='_lena_std_bw.bmp'; watermarked_image=imread(file_name); figure,imshow(watermarked_image),title('Watermarked Image') %% %%%%%%%%%%%%%%%%%% distortion %%%%%%%%%%%% % imwrite(watermarked_image,'temp.jpg','Quality',99); % watermarked_image2=imread('temp.jpg'); % psnr_Dist=psnr(watermarked_image2,watermarked_image,size(watermarked_image,1),size(watermarked_image,2)); % figure,imshow(watermarked_image2),title(strcat('distorted wked image, PSNR=',num2str(psnr_Dist))) % watermarked_image=watermarked_image2; % watermarked_image2 = imnoise(watermarked_image,'gaussian',0,2*10^(-6)); %1~7*10^(-6) % psnr_Dist=psnr(watermarked_image2,watermarked_image,size(watermarked_image,1),size(watermarked_image,2)); % figure,imshow(watermarked_image2),title(strcat('distorted wked image, PSNR=',num2str(psnr_Dist))) % watermarked_image=watermarked_image2; watermarked_image2 = imnoise(watermarked_image,'salt & pepper',0.30); % 0~100% psnr_Dist=psnr(watermarked_image2,watermarked_image,size(watermarked_image,1),size(watermarked_image,2)); figure,imshow(watermarked_image2),title(strcat('distorted wked image, PSNR=',num2str(psnr_Dist))) watermarked_image=watermarked_image2; %% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %% determine size of watermarked image Mw=size(watermarked_image,1); %Height Nw=size(watermarked_image,2); %Width %% use lsb of watermarked image to recover watermark watermark = uint8(zeros(Mw,Nw)); for i = 1:Mw for j = 1:Nw watermark(i,j)=bitget(watermarked_image(i,j),1); end end % scale the recovered watermark % watermark=2*double(watermark); %% display processing time elapsed_time=cputime-start_time %% read in original watermark %%%%%%%%%%%%%%%%%%%%%%%%%% the first key image %%%%%%%%% file_name='key.bmp'; message=imread(file_name); message1=message; % pixel values: 1, 2 % convert to double for normalization, then back again message=double(message); % message=fix(message./2); % % pixel values: 1, 2 ==> 0, 1%******** message=fix(message./128); % % pixel values: 1, 2 ==> 0, 1 message=uint8(message); %%%%%%%%%%%%%%%%%%%%%%%%%% the second key image %%%%%%%%% % path_image = 'cuc.jpg'; % im0 = double(imread(path_image)); % figure,imshow(uint8(im0)),title('color ico of cuc') % dimIm = ndims(im0); % if dimIm == 3 % imRgb = rgb2hsv(im0); % output float % im0 = imRgb(:,:,3); % original image - value(luminance) channel % end % figure,imshow(uint8(im0)),title('gary ico of cuc') % im0 = double(imresize(uint8(im0), 0.8)); % figure,imshow(uint8(im0)),title('resized gary ico of cuc') % message = im0; % message1=message; % pixel values: 1, 2 % % convert to double for normalization, then back again % message=double(message); % % message=fix(message./2); % % pixel values: 1, 2 ==> 0, 1 %******** % % message=fix(message./128); % % pixel values: 1, 2 ==> 0, 1 % message= message>220; % thresholding % figure,imshow(message),title('binary resized gary ico of cuc') % message=uint8(message); %% determine size of message object Mm=size(message,1); %Height Nm=size(message,2); %Width %% title the message object out to cover object size to generate watermark watermarkOrig = uint8(zeros(Mw,Nw)); for i = 1:Mw for j = 1:Nw % watermark(i,j)=message(mod(i,Mm)+1,mod(j,Nm)+1); watermarkOrig(i,j)=message(mod(i-1,Mm)+1,mod(j-1,Nm)+1); % 从（2,2）位置开始复制-平铺 ==》从（1,1）位置开始复制-平铺 end end %% display wked image figure, subplot(2,2,1),imshow(watermarked_image),title('(Distored) Watermarked Image'),colorbar % display recovered watermark subplot(2,2,2),imshow(watermark,[]),title('Recovered Watermark'),colorbar % display original watermark subplot(2,2,3),imshow(watermarkOrig,[]),title('Original Watermark'),colorbar % display difference between recovered watermark and original watermark Wk_Diff_sum = 1-sum(sum(abs(double(double(watermark)-double(watermarkOrig)))))/Mw/Nw; subplot(2,2,4),imshow(abs(double(double(watermark)-double(watermarkOrig))),[0,1]),title(strcat('正确检出率=',num2str(Wk_Diff_sum))),colorbar