{HEAD ~ The method} 1 wherein {TAIL ~ the step} of comparing includes generating an output corresponding to a 3 D position of any said obstacle relative to said 3 D reference model 
wherein
{ HEAD ~ The method } 1 wherein { TAIL ~ the step } of comparing includes generating an output corresponding to a 3 D position of any said obstacle relative to said 3 D reference model
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH