title: OpeNni: Color coordinates to depth coordinates
body: <p>I was wondering how can I convert a coordinate that i acquired from a 
  full res color image to coordinates in the depth stream.</p>
  
  <p>E.g, i got (763,234) from the full res color and i want to know what 
  is the (x,y,z)  from the depth image ? 
  (btw i'm doing this in java, but an answer in c++ is probably easily 
  translatable) </p>
  
  <p>Thx in advance</p>