Synopsis
		sftxpscan < cmp.rsf > scan.rsf v0= dv= nv= extend=4 mute=12 str=0.5 smin=1.0 smax=2.0

Parameters
		float dv= step in velocity   int extend=4 trace extension   int mute=12 mute zone   int nv= number of scanned velocities   float smax=2.0 maximum heterogeneity   float smin=1.0 minimum heterogeneity   float str=0.5 maximum stretch allowed   float v0= first scanned velocity