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Matrix dimensions must agree. Error in pre (line 146) inv_trans_img(:,l)=v{m-1}.*trans_img(:,l);..............I am getting this error if anybody would help me to sortout this then it will be a goodhelp
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if true
% code
endclear all
close all
clc
[filename, pathname] = uigetfile('*.bmp', 'Pick an M-file');
if isequal(filename,0) || isequal(pathname,0)
warndlg('Image is not selected');
else
a=imread(filename);
figure(1)
imshow(a)
a=rgb2gray(a);
figure(2);
imshow(a)
title('converted image from rgb to gray')
a=imresize(a,[512,512]);
figure(3)
imshow(a,[])
title('cover image')
a=im2double(a);
%imshow(a);
end
[filename, pathname] = uigetfile('*.bmp', 'Pick an M-file');
if isequal(filename,0) || isequal(pathname,0)
warndlg('Image is not selected');
else
secret=imread(filename);
%imshow(secret);
figure(4)
imshow(secret,[])
title('Watermark Image')
end
m=1;
% k=30;
for i=1:8:256
for j=1:8:256
for x=0:7
for y=0:7
img(x+1,y+1)=a(i+x,j+y);
end
end
k=0;
for l=1:8
img_expect{k+1}=img(:,l)*img(:,l)';
k=k+1;
end
imgexp=zeros(8:8);
for l=1:8
imgexp=imgexp+(1/8)*img_expect{l};%expectation of E[xx']
end
img_mean=zeros(8,1);
for l=1:8
img_mean=img_mean+(1/8)*img(:,l);
end
img_mean_trans=img_mean*img_mean';
img_covariance=imgexp - img_mean_trans;
[v{m},d{m}]=eig(img_covariance);
temp=v{m};
m=m+1;
for l=1:8
v{m-1}(:,l)=temp(:,8-(l-1));
end
for l=1:8
trans_img1(:,l)=v{m-1}*img(:,l);
end
for x=0:7
for y=0:7
transformed_img(i+x,j+y)=trans_img1(x+1,y+1);
end
end
end
end
% transformed image is assigned to cover_object
cover_object=double(transformed_img);
Mc=size(cover_object,1); %Height
Nc=size(cover_object,2); %Width
% determine maximum message size based on cover object, and blocksize
max_message=Mc*Nc;
% read in the message image
message=double(secret);
Mm=size(message,1); %Height
Nm=size(message,2); %Width
% reshape the message to a vector
message=round(reshape(message,Mm*Nm,1)./256);
% check that the message isn't too large for cover
if (length(message) > max_message)
error('Message too large to fit in Cover Object')
end
% pad the message out to the maximum message size with ones's
message_vector=ones(1,max_message);
message_vector(1:length(message))=message;
% generate shell of watermarked image
watermarked_image=cover_object;
% read in key for PN generator
file_name='_key.bmp';
% key=double(imread(file_name))./256;
% reset MATLAB's PN generator to state "key"
rand('state',35);
% generate PN sequence
pn_sequence_zero=round(2*(rand(1,sum(sum(512)))-0.5));
pn_sequence_one=round(2*(rand(1,sum(sum(512)))-0.5));
% process the image in blocks
%x=1;
%y=1;
for kk = 1:length(message_vector)
% transform block using DCT
dct_block=(cover_object(1:256,1:256));
% if message bit contains zero then embed pn_sequence_zero into the mid-band
% componants of the dct_block
ll=1;
if (message_vector(kk)==0)
for ii=1:256
for jj=1:256
if (dct_block(jj,ii)==1)
dct_block(jj,ii)=(dct_block(jj,ii))+k*pn_sequence_zero(ll);
ll=ll+1;
end
end
end
else
for ii=1:256
for jj=1:256
if (dct_block(jj,ii)==1)
dct_block(jj,ii)=(dct_block(jj,ii))+k*pn_sequence_zero(ll);
ll=ll+1;
end
end
end
end
% transform block back into spatial domain
% watermarked_image(1:256,1:256)=((dct_block));
% move on to next block. At and of row move to next row
% % if (x+512) >= Nc
% x=1;
% y=y+512;
% else
% x=x+512;
% end
end
mask=[1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 1 ];
trans_img=dct_block'.*1;
for l=1:256
inv_trans_img(:,l)=v{m-1}.*trans_img(:,l);
end
for x=0:3
for y=0:3
inv_transformed_img(i+x,j+y)=inv_trans_img(x+1,y+1);
imwrite(uint8(inv_transformed_img),'Lena_wtermarked_image.bmp','bmp');
end
end
figure(5)
imshow(transformed_img);
title('transformed image')
figure(6)
imshow(inv_transformed_img);
title('inverse transformed image')
% imwrite(uint8(inv_transformed_img),'Lena_wtermarked_image.bmp','bmp');
figure(7)
LWI=imread('Lena_wtermarked_image.bmp');
imshow(LWI);
title('Watermarked Image')
4 Comments
Walter Roberson
on 9 Oct 2018
I doubt that anyone will read the code thoroughly and work through the undocumented mathematical operations and mentally work backwards to figure out what a useful set of operations would be instead and tell you the appropriate code, all without even having your test image.
Answers (0)
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