How to retrieve an embedded image from a .png image?

Hello, I have a university steganography project where I need to retreive a hidden image from a .png RGB image. The embedded image is hidden in the LSBs of the original .png image. I am having problems extracting the hidden information from the image, does anyone have a code that does a similar function?

Thank you

Answer 1

[Abhisek Pradhan]

Considering it as an 16-bit image. The primary image is stored in the most significant byte, while the secondary image is stored in the least significant byte.

Decomposing the image :

imdata = imread('image.png');

Converting RGB 3-D Array to a Vector and typecasting to unit8 (in case the hidden image is stored in the 8 LSBs ).

pixelVals = imData(:);
pixelValsConv = typecast(pixelVals, 'uint8');

Separating both the images:

% This generates a 2D array with first column denoting the most significant digit and the second column 
% denoting least significant digit.
pixelValsConv = reshape(pixelValsConv, 2, [])'; 
imDataPrimary = reshape(pixelValsConv(:, imOrder(1)), size(imData));
imDataSecondary = reshape(pixelValsConv(:, imOrder(2)), size(imData));

Displaying both the images:

figure;imshow(imDataPrimary);
figure;imshow(imDataSecondary);

[Ahmad Al Hamdan]

Thank you that was really helpful