title: track the user with camera in javascript and getuserMedia
body: <p>I need track to user with camera and I found the headtrackr library (<a href="https://github.com/auduno/headtrackr/" rel="nofollow">https://github.com/auduno/headtrackr/</a>) and is very useful because you can determine the body with the head reference, but give me problems when I cover my face with something or if I don´t have shirt.  What I really need is to separate the body from the background.
  Perhaps with a blending mode or something like that? any idea?
  Thanks.</p>