基于matlab四叉树图像分割

ubeautqq · 发表于 2021-5-14 15:07

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一、源代码

%Reversible Data hiding using Quad tree decomposition and histogrma
%shifting
%using quad tree to increase the hiding capacity
clc;
clear all;
close all;
z=1;
%--------------------reading the image------------------------
b=imread('goldhill.jpg');
I=rgb2gray(b);
figure(1);
imshow(I);
title('original image');
[m,n]=size(I);
figure(2);
imhist(I);
title('histogram of original image');
%--------------------quadtree decomposition---------------------
mindim=4;
S = qtdecomp(I,@Split,mindim,@Predicate);
%-------------------showing the block representation------------
blocks = repmat(uint8(0),size(S));
for dim = [512 256 128 64 32 16 8 4 2 1];
numblocks = length(find(S==dim));
if (numblocks > 0)
values = repmat(uint8(1),[dim dim numblocks]);
values(2:dim,2:dim,：） = 0;
blocks = qtsetblk(blocks,S,dim,values);
end
end
blocks(end,1:end) = 1;
blocks(1:end,end) = 1;
figure(3);
imshow(blocks,[]);
title('decomposed image blocks');
%-------------------showing fullimage-----------------------------------
vals1 = repmat(uint8(0),size(S));
for dim = [512 256 128 64 32 16 8 4 2 1]
[vals,r,c]=qtgetblk(I,S,dim);
numblocks = length(find(S==dim));
if (numblocks > 0)
values = repmat(uint8(1),[dim dim numblocks]);
values(2:dim,2:dim,：） = vals(2:dim,2:dim,1:numblocks) ;
vals1 = qtsetblk(vals1,S,dim,values);
end
end
figure(4);
imshow(vals1,[]);
title('decomposed image');
%----------------inputting the message/data to be hide---------------------
hide_data=input('Enter the data to be hide'); %for manual input
%cell_data=textread('myfile.txt', '%s', 'whitespace', ''); %reading data from text file
%hide_data=char(cell_data);
bin_data=convert_binary(hide_data); %calling function to convert data to binary
binary_data=bin_data';
size_binary=size(binary_data,1)*size(binary_data,2);
bin=1;
a=1;
% %-------------------embedding data in the image blocks---------------------
vals5 = repmat(uint8(0),size(S));
pd=1;
q=1;
ind=1;
rec_data(size_binary)=0;
for h=1:size_binary
rec_data(h)=0;
end
for dim = [512 256 128 64 32 16 8 4 2 1]
[vals2,r,c]=qtgetblk(I,S,dim);
numblocks = length(find(S==dim));
if (numblocks > 0)
values = repmat(uint8(1),[dim dim numblocks]);
values1 = repmat(uint8(1),[dim dim numblocks]);
full_hideimage = repmat(uint8(1),[dim dim numblocks]);
values(1:dim,1:dim,：） = vals2(1:dim,1:dim,1:numblocks) ;
%full_hideimage(1:dim,1:dim,：）=vals2(1:dim,1:dim,1:numblocks);
for i=1:size(values,3)
get_block=values(:,:,i);
newblock=values(:,:,i);
hide_image=values(:,:,i);
recover_block=values(:,:,i);
original=get_block;
l_block=length(get_block);
count(255)=0;
for h=1:255
count(h)=0;
end
for k=1:255
for l=1:l_block
for j=1:l_block
if get_block(l,j)==k
count(k)=count(k)+1;
end
end
end
end
[C,max_point]=max(count);
[C1,min_point]=min(count);
for l=1:l_block
for j=1:l_block
if (get_block(l,j)>min_point)&&(get_block(l,j)<max_point)
newblock(l,j)=get_block(l,j)+1;
elseif get_block(l,j)==(max_point+1)
newblock(l,j)=get_block(l,j)+1;
else
newblock(l,j)=get_block(l,j);
end
end
end
for l=1:l_block
for j=1:l_block
if (newblock(l,j)==max_point)
if (bin<=size_binary)
dat=binary_data(bin);
if dat==dec2bin(1)
hide_image(l,j)=newblock(l,j)+ 1;
else
hide_image(l,j)=newblock(l,j);
end
else
hide_image(l,j)=newblock(l,j);
end
bin=bin+1;
else
hide_image(l,j)=newblock(l,j);
end
end
end
full_hideimage(:,:,i)=hide_image;
end
%------------showing data hided image---------------
values(1:dim,1:dim,1:numblocks)=full_hideimage(1:dim,1:dim,1:numblocks);
vals5 = qtsetblk(vals5,S,dim,values);
end
end
figure(5);
imshow(vals5,[]);
title('data hided image');
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