SUVELAN_NCCS - compute stacking VELocity panel for cdp gathers
using Normalized CrossCorrelation Sum
suvelan_uccs stdout [optional parameters]
Optional Parameters:
nx=tr.cdpt number of traces in cdp
nv=50 number of velocities
dv=50.0 velocity sampling interval
fv=1500.0 first velocity
smute=1.5 samples with NMO stretch exceeding smute are zeroed
dtratio=5 ratio of output to input time sampling intervals
nsmooth=dtratio*2+1 length of smoothing window
verbose=0 =1 for diagnostic print on stderr
pwr=1.0 semblance value to the power
Notes:
Normalized CrossCorrelation sum: sum all possible crosscorrelation
trace pairs in a CMP gather for each trial velocity and zero-offset
two-way travel time inside a time window. This coherence measure is
normalized by dividing each crosscorrelation trace pair by the geometric
mean of the energy, inside the chosen time window, of each trace pair
involved in each crosscorrelation. Then, to achieve a maximum amplitude
of unity, the result is multiplied by 2/(M(M-1)), which is the inverse
of the total number of crosscorrelation. The normalization allows to
bring out weak reflection as long as these reflections have moveouts close
to a hyperbola.
Credits:
CWP: Valmore Celis, Sept 2002
Based on the original code: suvelan.c
Colorado School of Mines: Dave Hale, c. 1989
Trace header fields accessed: ns, dt, delrt, offset, cdp, cdpt
Trace header fields modified: ns, dt, offset, cdp
Reference: Neidell, N.S., and Taner, M.T., 1971, Semblance and
other coherency measures for multichannel data:
Geophysics, 36, 498-509.