{TAIL ~ A method} 4, wherein scanning {HEAD ~ said interference pattern} comprises scanning said pattern directly with a television camera 
{ TAIL ~ A method } 4 , wherein scanning { HEAD ~ said interference pattern } comprises scanning said pattern directly with a television camera
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH