Reconstuction of RGB image after embedding

I'm currently preforming LSB operations on RGB image for each channel

But I'm confused on the way to reconstruct the image after manipulating the LSB bits

%Load Cover Image 24-bit RGB
Cover_Image=imread('RGB_24bits_palette_sample_image.jpg');

% Extract the individual red, green, and blue color channels.
redChannel = Cover_Image(:, :, 1);
greenChannel = Cover_Image(:, :, 2);
blueChannel = Cover_Image(:, :, 3);

% Get LSB's of each pixel for every channel.
redLsb = rem(redChannel, 2);
greenLsb = rem(greenChannel, 2);
blueLsb = rem(blueChannel, 2);

%Resizing the LSB into vector

redLsbVector = reshape(redLsb.',1,[]);
greenLsbVector = reshape(greenLsb.',1,[]);
blueLsbVector = reshape(blueLsb.',1,[]);

%Load Hidden message 
HiddenMessage = 'Hello';

%Convert Hidden message to Binary
HiddenMessageInBinary = reshape(dec2bin(HiddenMessage, 8)', 1, []) - '0';

%Start Embedding
MissMatchCount = 0;
for i=1:length(HiddenMessageInBinary)
    if redLsbVector(i)~= HiddenMessageInBinary(i)
    MissMatchCount=MissMatchCount+1;
    %embed
    redLsbVector(i) = HiddenMessageInBinary(i);
    end
end

%Reconstruct the image

Answer 1

[Geoff Hayes]

Geboz - rather than updating the redLsbVector every time that you are changing a bit (because of the message), why not just update the redChannel data directly? You would first need to remove the transpose operation that occurs during the reshaping, so this code would now become

 redLsbVector   = reshape(redLsb,1,[]);
 greenLsbVector = reshape(greenLsb,1,[]);
 blueLsbVector  = reshape(blueLsb,1,[]);

Then, the embedding of the message code changes to

 for i=1:length(HiddenMessageInBinary)
    if redLsbVector(i)~= HiddenMessageInBinary(i)

        MissMatchCount=MissMatchCount+1;

        % change the least significant bit of the ith byte
        redChannel(i) = bitxor(redChannel(i),1);
    end
 end

After the above code (so try with a breakpoint), you should be able to observe that HiddenMessageInBinary is identical to

 redLsb = rem(redChannel, 2);
 redLsb(1:40)

which suggests that we have embedded the message correctly in these first 40 bytes of the red channel.