Error. Inputs must have the same size

Hello ,I recive the following error for the code bellow .Can you help me please?

Error using bitor.Inputs must have the same size. (line 12)

clc;
clear all;
close all;

cover = input('alegeti poza' , 's');
message = input('introduceti textul dorit ', 's');

x = imread(cover);         % cover message
y = imread(message);    % message image
n = 3  %input('Enter the no of LSB bits to be subsituted- '); 

S = uint8(bitor(bitand(x,bitcmp(2^n-1,8)),bitshift(y,n-8))); %Stego
E = uint8(bitand(255,bitshift(S,8-n))); %Extracted

origImg = double(y);   %message image
distImg = double(E);   %extracted image

[M N] = size(origImg);
distImg1=imresize(distImg,[M N]);
error = origImg - distImg1;
MSE = sum(sum(error .* error)) / (M * N);
if(MSE > 0)
    PSNR = 10*log10(M*N./MSE);
else
    PSNR = 99;
end
disp('PSNR of message image to extracted image is')
disp(abs(PSNR))
disp('MSE is')
disp(abs(MSE))

Answer 1

[Jan]

The message means, that this fails:

bitor(bitand(x, bitcmp(2^n-1, 8)), bitshift(y, n-8))

Because the bitand and bitshift do not change the size of the inputs, the error is caused by the different sizes of x and y. Is it assumd that both images have the same size? If not, how do you want to consider different sizes?

[Walter Roberson]

One difficulty to watch out for is that one of your images might be stored as RGB even though it looks like greyscale, and the other might be stored as true grayscale.

But more likely your images are just different sizes. You should be taking into account that the message will seldom be exactly the same size as the cover image.

Answer 2

[john j sanabria]

nop the error is about bitcmp(2^n-1,8), any n it just said "Error using bitcmp ASSUMEDTYPE must be an integer type name."

[Jan]

But the OP has explained:

 Error using bitor.Inputs must have the same size. (line 12)

In older Matlab versions, e.g. R2009a, the 2nd input of bitcmp was a numerical value.

[john j sanabria]

one possible solution is "bitand(x,bitcmp(2^n-1,'uint8')" with MATLAB Version: 9.0.0.341360 (R2016a)

Answer 3

[Nazish Iqbal]

%ENCRYPTION

clear all

%READ THE COVER IMAGE

I = imread('C:\Users\dell\Desktop\peppers.jpg');

%READ THE IMAGE TO HIDE

J = imread('C:\Users\dell\Desktop\cube.jpg');

%PREALLOCATE THE OUTPUT IMAGE

Output = zeros(size(I));

%REPRESENT THE NUMBER OF ROWS AND COLUMNS OF THE SECRET IMAGE

%IN BINARY FORMAT

Jsize = de2bi([size(J,1),size(J,2)]);

%RED,GREEN AND BLUE COMPONENTS OF THE SECRET IMAGE

Red_Ch = J(:,:,1);

Green_Ch = J(:,:,2);

Blue_Ch = J(:,:,3);

%CONVERT THE RED COMPONENT OF THE SECRET IMAGE INTO BINARY FORMAT

Encrypt_Red = de2bi(Red_Ch(:),8)';

Encrypt_Red = Encrypt_Red(:)';

%CONVERT THE GREEN COMPONENT OF THE SECRET IMAGE INTO BINARY FORMAT

Encrypt_Green = de2bi(Green_Ch(:),8)';

Encrypt_Green = Encrypt_Green(:)';

%CONVERT THE BLUE COMPONENT OF THE SECRET IMAGE INTO BINARY FORMAT

Encrypt_Blue = de2bi(Blue_Ch(:),8)';

Encrypt_Blue = Encrypt_Blue(:)';

%CALCULATE THE INTERVAL AND CONVERT IT INTO BINARY FORMAT

dt=floor((size(I,1)*size(I,2))/numel(Encrypt_Red));

Bi_dt = de2bi(dt,8);

Info_data = [Bi_dt,Jsize(1,:),Jsize(2,:)];

%RED,GREEN AND BLUE COMPONENT OF THE COVER IMAGE

Red_mat = I(:,:,1);

Green_mat = I(:,:,2);

Blue_mat = I(:,:,3);

% INTERVAL,NUMBER OF COLUMNS, NUMBER OF ROWS

Red_mat(1:24) = bitset(Red_mat(1:24),1,Info_data);

Green_mat(1:24) = bitset(Green_mat(1:24),1,Info_data);

Blue_mat(1:24) = bitset(Blue_mat(1:24),1,Info_data);

%%REPLACE THE LEAST SIGNIFICANT BIT OF THE COVER IMAGE

%WITH THE BINARY FORMAT OF THE SECRET IMAGE

EndValue = numel(Encrypt_Red)*dt+24;

Red_mat(25:dt:EndValue) = bitset(Red_mat(25:dt:EndValue),1,Encrypt_Red);

Green_mat(25:dt:EndValue) = bitset(Green_mat(25:dt:EndValue),1,Encrypt_Green);

Blue_mat(25:dt:EndValue) = bitset(Blue_mat(25:dt:EndValue),1,Encrypt_Blue);

%ENCRYPTED IMAGE

Output(:,:,1) = Red_mat;

Output(:,:,2) = Green_mat;

Output(:,:,3) = Blue_mat;

Output = uint8(Output);

figure,subplot(121),imshow(I); subplot(122),imshow(Output);

%DIFFERENCE BETWEEN THE ORIGINAL AND THE ENCRYPTED IMAGE

figure,imagesc(double(I)-double(Output));colormap(jet);colorbar;

%WRITE THE ENCRYPTED IMAGE IN THE PNG FORMAT

imwrite(Output,'Encrypt_Image1.png');

stuck in line 52.kindly help me