title: Does cv2.Canny() perform a Gaussian blur?
body: <p>I know it's important to apply Gaussian blur to an image before using Canny to detect edges. My question is: does <code>cv2.Canny()</code> do Gaussian blur on its own or it is necessary to apply <code>cv2.GaussianBlur()</code> before <code>cv2.Canny()</code>? The documentation isn't clear on this point.</p>