Can any one have a code where a .wav file embedded into a image as a watermark using LSB technique?

Image to image embedding using LSB is done.Just need a code where audio file will be embedded in image and create a new watermarked image.

[Walter Roberson]

How does this differ from https://www.mathworks.com/matlabcentral/answers/1659580-recently-i-have-a-work-to-watermark-a-image-using-lsb-method-now-i-try-to-watermark-a-audio-to-a-ima ?

Answer 1

[Image Analyst]

Try this:

% Demo by Image Analyst to hide an audio signal in a uint8 gray scale image by encoding it in the least significant bit.
%============================================================================================================================================
% Initialization Steps.
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 15;
markerSize = 4;
%============================================================================================================================================
% Read in image
% grayImage = imread('moon.tif'); % This image is too small to contain the sound file.
baseFileName = 'concordorthophoto.png';
grayImage = imread(baseFileName); % A uint8 image.
numPixels = numel(grayImage);
subplot(2, 2, 1);
imshow(grayImage, []);
impixelinfo;
caption = sprintf('Original Image : "%s"', baseFileName);
title(caption, 'FontSize', fontSize)
%============================================================================================================================================
% Read in demo audio file that ships with MATLAB.
[y, fs] = audioread("handel_audio.wav");
y = y(:); % If stereo, stack left channel on top of right channel.
% Get the time axis
t = linspace(0, length(y) / fs, length(y))';
subplot(2, 2, [3,4]);
plot(t, y, 'b-');
grid on;
yline(0, 'Color', 'k'); % Draw line along x axis.
title('Original Audio Signal vs. Time that is Encoded into Above Right Image', 'FontSize', fontSize)
xlabel('Time (seconds)', 'FontSize', fontSize)
ylabel('Audio Signal', 'FontSize', fontSize)
ylim([-1, 1]);
xlim([0, max(t)]);
drawnow;	% Force immediate screen painting so we can see the inputs while the encoding and decoding process go on.
% Play the sound.
% playerObject = audioplayer(y, fs);
% play(playerObject)
% Convert y to 16 bits to have enough resolution so that the sound signal value won't be changed much due to round off error.
y16 = uint16(rescale(y, 0, 65535));
% Sound was converted to uint16 so we will need 16 pixels to store to store one sound value.
% Make an output image initialized to the same as the original image.
stegoImage = grayImage;
% See if the image is big enough to hide all bits of the audio signal.
numPixelsRequired = length(y) * 16;
if numPixels < numPixelsRequired
    errorMessage = sprintf('Cannot fit image.\nThe image is %d elements long.\nThe sound is %d elements long.\nThe sound file needs the image to have at least %d pixels (= 16 * %d) to contain the entire sound.\n', ...
        numPixels, length(y), numPixelsRequired, length(y))
    uiwait(errordlg(errorMessage));
else
    fprintf('The image is %d elements long.\nThe sound is %d elements long.\nThe sound file needs the image to have at least %d pixels (= 16 * %d) to contain the entire sound.\n', ...
        numPixels, length(y), numPixelsRequired, length(y));	
end
%============================================================================================================================================
% Now encode the audio signal in the least significant bit of the uint8 gray scale image.
for k = 1 : numel(y16)
    binaryNumberString = dec2bin(y16(k), 16);
    if mod(k, 10000) == 0
        fprintf('Changing pixel #%d of %d.\n', k, numel(y16));
    end
    % 	fprintf('%d in uint16 is %s in binary', y16(k), binaryNumberString);
    imageIndex = (k - 1) * 16 + 1;
    these16GrayLevels = stegoImage(imageIndex : imageIndex + 15);
    for k2 = 1 : length(binaryNumberString)
        gl = these16GrayLevels(k2);
        if binaryNumberString(k2) == '1'
            % Image gray level needs to be odd.
            % If the gray level is not already odd, make it odd.
            if rem(gl, 2) == 0 % if it's even...
                % It's even.  Add 1 to it to make it odd.
                gl = gl + 1;
                stegoImage(imageIndex + k2 - 1) = gl;
            end
        else % binaryNumberString(k2) == '0'
            % Image gray level needs to be even.
            % If the gray level is not already even, make it even.
            if rem(gl, 2) == 1 % If it's odd...
                % It's odd.  Add 1 to it to make it even, unless it's already 255 because we can't have a value of 256 for a uint8 variable.
                if gl <= 254
                    gl = gl + 1;
                else
                    % Value is 255 initially.  Make it even by making it 254, since we can't do 256.
                    gl = 254;
                end
                stegoImage(imageIndex + k2 - 1) = gl;
            end
        end
    end
    % 	these16GrayLevelsNow = stegoImage(imageIndex : imageIndex + 15)
end
subplot(2, 2, 2);
imshow(stegoImage, []);
impixelinfo;
title('With embedded sound file', 'FontSize', fontSize)
drawnow;
% Maximize the figure.
g = gcf;
g.WindowState = 'maximized';
g.Name = 'Demo by Image Analyst';
g.NumberTitle = 'off';
%============================================================================================================================================
% Now undo the encoding process and recover the hidden sound 
% by looking at the last (least significant) bit of the image gray levels and assigning that to a new sound.
yExtracted = zeros(length(y16), 1);
counter = 1;
for k = 1 : 16 : numel(y16) * 16
    % Get a vector of 16 pixel values.
    these16GrayLevels = stegoImage(k : k+15);
    % Get the least significant bits of those 16 pixel values.
    b = bitget(these16GrayLevels, 1);
    % Convert to a string, then to a decimal number.
    soundValue = bin2dec(sprintf('%c', b+48));
    if mod(counter, 10000) == 0
        fprintf('Assigning sound sample #%d of %d.\n', counter, numel(y16));
    end
    % Assign that sound value to the output sound signal.
    yExtracted(counter) = soundValue;
    counter = counter + 1;
end
% Convert back y from uint16 back to floating point like the original y.
yRecovered = yExtracted / 65535;
%============================================================================================================================================
% Play the recovered sound.
playerObject = audioplayer(yRecovered, fs);
play(playerObject)
% Double check that they're the same.
% If they're the same, the value below should be 1, true.
theyAreTheSame = isequal(y16, yExtracted)