stegocombine.m

stegenogrpahy in matlab based on dwt

        % force wolverine restored image color values to be between 0 and 255
        wolverine_restored_big_image = uint8( wolverine_restored_big_image );

        if DISPLAY_INTERMEDIATE_IMAGES

            % display the restored wolverine.jpg that is still the size of tree_path.jpg
            figure, imshow( wolverine_restored_big_image ); title( 'Restored Wolverine - Tree Path Size - Combined Image Resized' );
        end

        % resize wolverine_restored_big_image to the size of the original wolverine.jpg
        wolverine_restored_image = imresize( wolverine_restored_big_image, [ original_wolverine_y_size , original_wolverine_x_size ] );

        % display the restored wolverine image that is the original wolverine.jpg size
        figure, imshow( wolverine_restored_image ); title( 'Restored Wolverine - Original Size - Combined Image Resized' );
                
        % compute the Peak Signal-to-Noise Ratio (PSNR)
        % Displayed in the Matlab command window
        mean_square_error = sum( sum( sum( ( original_wolverine_image - wolverine_restored_image ).^2 ) ) ) / double( original_wolverine_x_size * original_wolverine_y_size * 3 );
        disp(' ')
        disp('The PSNR after resizing the combined image:')
        PSNR = 10 * log10( ( 255 )^2 / mean_square_error )
    end
    
    % try to restore the wolverine image from the combined image when the
    % combined image is made a heavily compressed .jpg
    if (DISPLAY_TESTING_IMAGES == 2) || (DISPLAY_TESTING_IMAGES == 4)
    
        % accepts values 0 to 100
        % even if you specify 100 Matlab will compress the image to a minor
        % degree, if you want absolutely no loss set PERCENT_OF_COMPRESSION
        % to 100 and add this line to the inside of the imwrite function:
        % , 'Mode', 'lossless'
        PERCENT_OF_COMPRESSION = 50;
        
        % uses Matlab to save the combined image as the compressed .jpg
        % image 'compressed_combined.jpg'
        imwrite( combined_image, 'combined_compressed.jpg', 'Quality', PERCENT_OF_COMPRESSION );
        
        % reads in the compressed combined .jpg image
        restored_combined_image = uint8( imread( 'combined_compressed.jpg' ) );

        if DISPLAY_INTERMEDIATE_IMAGES

            % display the compressed combined image .jpg image
            figure, imshow( restored_combined_image ); title( 'Combined Image - After Saving As a Compressed .jpg' );
        end

        % try to get the original values in wolverine.jpg
        for x_value = 1:tree_path_x_size
            for y_value = 1:tree_path_y_size
                wolverine_restored_big_image( y_value, x_value, 1 ) = ( restored_combined_image( y_value, x_value, 1 ) - original_tree_path_image( y_value, x_value, 1 ) ) / WEIGHTED_COMBINE_VALUE;
                wolverine_restored_big_image( y_value, x_value, 2 ) = ( restored_combined_image( y_value, x_value, 2 ) - original_tree_path_image( y_value, x_value, 2 ) ) / WEIGHTED_COMBINE_VALUE;
                wolverine_restored_big_image( y_value, x_value, 3 ) = ( restored_combined_image( y_value, x_value, 3 ) - original_tree_path_image( y_value, x_value, 3 ) ) / WEIGHTED_COMBINE_VALUE;
            end
        end

        % force wolverine restored image color values to be between 0 and 255
        wolverine_restored_big_image = uint8( wolverine_restored_big_image );

        if DISPLAY_INTERMEDIATE_IMAGES

            % display the restored wolverine.jpg that is still the size of tree_path.jpg
            figure, imshow( wolverine_restored_big_image ); title( 'Restored Wolverine - Tree Path Size - Combined Image Saved As a Compressed .jpg' );
        end

        % resize wolverine_restored_big_image to the size of the original wolverine.jpg
        wolverine_restored_image = imresize( wolverine_restored_big_image, [ original_wolverine_y_size , original_wolverine_x_size ] );

        % display the restored wolverine image that is the original wolverine.jpg size
        figure, imshow( wolverine_restored_image ); title( 'Restored Wolverine - Original Size - Combined Image Saved As a Compressed .jpg' );
        
        % compute the Peak Signal-to-Noise Ratio (PSNR)
        % Displayed in the Matlab command window
        mean_square_error = sum( sum( sum( ( original_wolverine_image - wolverine_restored_image ).^2 ) ) ) / double( original_wolverine_x_size * original_wolverine_y_size * 3 );
        disp(' ')
        disp('The PSNR after compressing the combined image to a .jpg:')
        PSNR = 10 * log10( ( 255 )^2 / mean_square_error )

    end

    % try to restore the wolverine image from the combined image when the
    % combined image has random added noise
    if (DISPLAY_TESTING_IMAGES == 3) || (DISPLAY_TESTING_IMAGES == 4)
    
        % specifies the maximum noise value
        MAX_NOISE_VALUE = 20;

        % specifies the approximate amount of noise
        % amount of noise = (1 / AMOUNT_OF_NOISE)%
        % 0 means every pixel of the combined image will have added noise
        % 1 means ~50% will have added noise, 2 means ~33%, 3 means ~25%, ....
        AMOUNT_OF_NOISE = 3;
        
        noise_image = uint8( zeros( tree_path_y_size, tree_path_x_size, 3 ) );
        
        % create a random noise image
        for x_value = 1:tree_path_x_size
            for y_value = 1:tree_path_y_size

                if round( rand() * AMOUNT_OF_NOISE ) == 0
                    noise_image( y_value, x_value, 1 ) = round( rand() * (MAX_NOISE_VALUE + 1) );
                    noise_image( y_value, x_value, 2 ) = round( rand() * (MAX_NOISE_VALUE + 1) );
                    noise_image( y_value, x_value, 3 ) = round( rand() * (MAX_NOISE_VALUE + 1) );
                end
                
            end
        end
                       
        % add the noise image to the combined image
        noise_added_combined_image = combined_image + noise_image;
        
        if DISPLAY_INTERMEDIATE_IMAGES

            noise_display_image = ones( tree_path_y_size, tree_path_x_size, 3 ) * 255;

            % create a random noise image
            for x_value = 1:tree_path_x_size
                for y_value = 1:tree_path_y_size

                    if noise_image( y_value, x_value, 1 ) ~= 0
                        noise_display_image( y_value, x_value, 1 ) = noise_image( y_value, x_value, 1 );
                    end
                    
                    if noise_image( y_value, x_value, 2 ) ~= 0
                        noise_display_image( y_value, x_value, 2 ) = noise_image( y_value, x_value, 2 );
                    end
                    
                    if noise_image( y_value, x_value, 3 ) ~= 0
                        noise_display_image( y_value, x_value, 3 ) = noise_image( y_value, x_value, 3 );
                    end

                end
            end
            
            % display the noise image
            figure, imshow( uint8(noise_display_image) ); title( 'Noise to Add to Combined Image' );
            
            % display the combined image with added noise
            figure, imshow( restored_combined_image ); title( 'Combined Image - After Adding Noise' );
        end

        % try to get the original values in wolverine.jpg
        for x_value = 1:tree_path_x_size
            for y_value = 1:tree_path_y_size
                                
                    wolverine_restored_big_image( y_value, x_value, 1 ) = ( noise_added_combined_image( y_value, x_value, 1 ) - original_tree_path_image( y_value, x_value, 1 ) ) / WEIGHTED_COMBINE_VALUE;
                    wolverine_restored_big_image( y_value, x_value, 2 ) = ( noise_added_combined_image( y_value, x_value, 2 ) - original_tree_path_image( y_value, x_value, 2 ) ) / WEIGHTED_COMBINE_VALUE;
                    wolverine_restored_big_image( y_value, x_value, 3 ) = ( noise_added_combined_image( y_value, x_value, 3 ) - original_tree_path_image( y_value, x_value, 3 ) ) / WEIGHTED_COMBINE_VALUE;                
            end
        end

        % force wolverine restored image color values to be between 0 and 255
        wolverine_restored_big_image = uint8( wolverine_restored_big_image );

        if DISPLAY_INTERMEDIATE_IMAGES

            % display the restored wolverine.jpg that is still the size of tree_path.jpg
            figure, imshow( wolverine_restored_big_image ); title( 'Restored Wolverine - Tree Path Size - Combined Image With Added Noise' );
        end

        % resize wolverine_restored_big_image to the size of the original wolverine.jpg
        wolverine_restored_image = imresize( wolverine_restored_big_image, [ original_wolverine_y_size , original_wolverine_x_size ] );

        % display the restored wolverine image that is the original wolverine.jpg size
        figure, imshow( wolverine_restored_image ); title( 'Restored Wolverine - Original Size - Combined Image With Added Noise' );
        
        % compute the Peak Signal-to-Noise Ratio (PSNR)
        % Displayed in the Matlab command window
        mean_square_error = sum( sum( sum( ( original_wolverine_image - wolverine_restored_image ).^2 ) ) ) / double( original_wolverine_x_size * original_wolverine_y_size * 3 );
        disp(' ')
        disp('The PSNR after adding random noise to the combined image:')
        PSNR = 10 * log10( ( 255 )^2 / mean_square_error )

    end
end