title: How can i change a pixel value from a grayscaled image using Opencv 2.3?
body: <p>When i read a grayscaled image using for example in Opencv  2.3:</p>
  
  <pre><code>Mat src = imread("44.png" ,0);
  </code></pre>
  
  <p>How can i access the pixel value of it?</p>
  
  <p>I know if its RGB i can use:</p>
  
  <pre><code>std::cout &lt;&lt; src.at&lt;cv::Vec3b&gt;(i,j)[0].
  </code></pre>
  
  <p>Thanks in advance.</p>