  Gravitational radiation is properly defined only at future null infinity
($\scri$), but in practice it is estimated from data calculated at a finite
radius. We have used characteristic extraction to calculate gravitational
radiation at $\scri$ for the inspiral and merger of two equal mass non-spinning
black holes. Thus we have determined the first unambiguous merger waveforms for
this problem. The implementation is general purpose, and can be applied to
calculate the gravitational radiation, at $\scri$, given data at a finite
radius calculated in another computation.
