reversible contrast mapping based watermarking on dicom image

Question

uthara ravi 2016-1-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/263078-reversible-contrast-mapping-based-watermarking-on-dicom-image

评论： uthara ravi 2016-1-13

i have written a code for watermarking on a dicom image based on reversible contrast mapping algorithm.

trouble shooted many times but didnt get the correct embedding and extraction. kindly help me to correct the same. the code is as follows

clc;
%code for separating the ROI and RONI of a DCM file
clear all;
close all;
[RONI,MAP]=dicomread('189.dcm');
InputImg1 = uint8(255*mat2gray(RONI));
% Display the Image
figure,imshow(InputImg1,[]);title('Select the region of interest(ROI)');
% Get Inputs from Mouse,Select 4 Seed Points in Image
[Col Row]=ginput(4);
c =Col;
r =Row;
% Select polygonal region of interest
BinaryMask = roipoly(InputImg1,c,r);
%figure,imshow(BinaryMask,[]); title('Selected Region of Interest')
%Create Buffer for ROI
ROI=zeros(512,512);
%Create Buffer for NONROI
RONI=zeros(512,512);
for i=1:512
for j=1:512
if BinaryMask(i,j)==1
ROI(i,j)=InputImg1(i,j);
else
RONI(i,j)=InputImg1(i,j);
end
end
end
%Display ROI and Non ROI
figure,imshow(ROI,[]);title('ROI');
impixelinfo
figure,imshow(RONI,[]);title('NON ROI');
img=uint8(ROI);
%img=imread('cameraman.tif');
%figure,imshow(img);
impixelinfo
%grouping the pixel pairs
[rows,cols]=size(img);
x1=img(:);
x2=buffer(x1,2);
pixels=x2';
p=pixels;
[row1,cols1]=size(pixels);
%watermark bit generation
wm=randsrc(row1,1,[0 1]);
for i=1:length(pixels)
    if (0<(2*pixels(i,1)-pixels(i,2)<=511)&& (bitget(pixels(i,1),1)==0)) && (0<(2*pixels(i,2)-pixels(i,1)<=511)&& (bitget(pixels(i,2),1)==0))
        a=pixels(i,1);
        b=pixels(i,2);
        pixels(i,1)=2*a-b;
        c(i,1)=2*a-b;
        pixels(i,2)=2*b-a;
        c(i,2)=2*b-a;
        pixels(i,1)=bitset(pixels(i,1),1,1);
        pixels(i,2)=bitset(pixels(i,1),1,wm(i));
        wmnew(i)=wm(i);
    else if (0<(2*pixels(i,1)-pixels(i,2)<=511)&& (bitget(pixels(i,1),1)==1)) && (0<(2*pixels(i,2)-pixels(i,1)<=511)&& (bitget(pixels(i,2),1)==1))
             pixels(i,1)=bitset(pixels(i,1),1,0);
        pixels(i,2)=bitset(pixels(i,1),1,wm(i));
        wmnew(i)=wm(i);
        else
                         pixels(i,1)=bitset(pixels(i,1),1,0);
                         wmnew(i)=bitget(pixels(i,2),1);
        end
    end
end
x3=pixels';
x4=x3(:);
x5=buffer(x4,512);
figure,imshow(x5)
title('embedded image');
impixelinfo
%1.grouping the pixel pairs
[rows,cols]=size(img);
y1=x5(:);
y2=buffer(y1,2);
expixels=y2';
for i=1:length(expixels)
    if (bitget(expixels(i,1),1)==1)
        extractedwm(i)=bitget(expixels(i,2),1);
        expixels(i,1)=bitset(expixels(i,1),1,0);
        expixels(i,2)=bitset(expixels(i,2),1,0);
expixels(i,1)=ceil(((2*expixels(i,1))+expixels(i,2))/3);
 expixels(i,2)=ceil(((2*expixels(i,2))+expixels(i,1))/3);
    else
        if (bitget(expixels(i,1),1)==1) && (0<(2*expixels(i,1))-expixels(i,2)<+ 511 && 0<(2*expixels(i,2))-expixels(i,1) <=511)
         expixels(i,1)=bitset(expixels(i,1),1,1);
        expixels(i,2)=bitset(expixels(i,2),1,1);
          else 
                      expixels(i,1)=bitset(expixels(i,1),1,wmnew(i));
          end
      end
  end
  y3=expixels';
  y4=y3(:);
  y5=buffer(y4,512);
  figure,imshow(y5)
  title('extracted image');
  impixelinfo