addText.m

function [output] = addText(image, text)
   red_data = image(:,:,1);
   text = strcat(num2str(length(text), '%03.f'), text);
   binary_data = dec2bin(text)'; 
   data_to_encode = str2num(binary_data(:));
   for i = 1:length(data_to_encode)
     red_data(i) = bitset(red_data(i), 1, data_to_encode(i));
   end
   output = image;
   output(:,:,1) = red_data;
end