title: How does "bwareaopen" work?
body: <p>I saw the documentation of <code>bwareaopen</code>, but what was confusing me is the number of pixels. When we say <code>8-neighbourhood</code>, doesn't that mean <code>9-pixels</code>? In this function, we specify the number of pixels, and if you see the example provided in the documentation, you will find that they mention <code>50-pixels</code>, does that simply mean a <code>10x5</code> window?</p>
  
  <p>So, if we specify the number of pixels, what will the function exactly do? It mentions removing small pixels. What does this exactly mean? Isn't each square in an image matrix considered a square? What is a <code>small</code> pixel in this case?</p>
  
  <p>Thanks.</p>