title: Get image data of known process
body: <p>For Imageprocessing I want to get all pixel information from a given process.
  Concrete its for testing an image hashing algorithm for identifying hearthstone cards, so i need to get a screenshot of the given process.
  How can I solve it in windows?
  My idea so far:</p>
  <blockquote>
  <ol>
  <li><p>Get the process name.</p>
  </li>
  <li><p>Get the process ID</p>
  </li>
  <li><p>Get Window Handle</p>
  </li>
  </ol>
  </blockquote>
  <p>I have no idea how to go further from this point.
  I hope it understandable what I want to achieve.</p>