title: CreateImageHeader in OpenCV 3.x
body: <p>I am having trouble with this line of code.</p>
  <pre><code>cv_im = cv.CreateImageHeader(pil_im.size, cv.IPL_DEPTH_8U, 1)
  </code></pre>
  <p>Now, I am using OpenCV 3.x which apparently has no such attribute. Is there any substitute for that in version 3.x?</p>