title: OpenCV: Find all non-zero coordinates of a binary Mat image
body: <p>I'm atttempting to find the non-zero (x,y) coordinates of a binary image. </p>
  
  <p>I've found a few references to the function <code>countNonZero()</code> which only counts the non-zero coordinates and <code>findNonZero()</code> which I'm unsure how to access or use since it seems to have been removed from the documentation completely.</p>
  
  <p><a href="https://stackoverflow.com/questions/15229951/opencv-locations-of-all-non-zero-pixels-in-binary-image">This</a> is the closest reference I found, but still not helpful at all. I would appreciate any specific help.</p>
  
  <p>Edit:
  - To specify, this is using C++</p>