SYNOPSIS
PERL PROGRAM NAME:
AUTHOR: Juan Lorenzo (Perl module only)
DATE:
DESCRIPTION:
Version:
USE
NOTES
Examples
SYNOPSIS
SEISMIC UNIX NOTES SUGAZMIGQ - SU version of Jeno GAZDAG's phase-shift migration
for zero-offset data, with attenuation Q.
sugazmig <infile >outfile vfile= [optional parameters]
Optional Parameters:
dt=from header(dt) or .004 time sampling interval
dx=from header(d2) or 1.0 midpoint sampling interval
ft=0.0 first time sample
ntau=nt(from data) number of migrated time samples
dtau=dt(from header) migrated time sampling interval
ftau=ft first migrated time sample
tmig=0.0 times corresponding to interval velocities in vmig
vmig=1500.0 interval velocities corresponding to times in tmig
vfile= name of file containing velocities
Q=1e6 quality factor
ceil=1e6 gain ceiling beyond which migration ceases
verbose=0 verbose = 1 echoes information
tmpdir= if non-empty, use the value as a directory path
prefix for storing temporary files; else if the
the CWP_TMPDIR environment variable is set use
its value for the path; else use tmpfile()
Note: ray bending effects not accounted for in this version.
The tmig and vmig arrays specify an interval velocity function of time.
Linear interpolation and constant extrapolation is used to determine
interval velocities at times not specified. Values specified in tmig
must increase monotonically.
Alternatively, interval velocities may be stored in a binary file
containing one velocity for every time sample in the data that is to be
migrated. If vfile is specified, then the tmig and vmig arrays are ignored.
Caveat: Adding Q is a first attempt to address GPR issues.
Credits:
Constant Q attenuation correction by Chuck Oden 5 May 2004
CWP John Stockwell 12 Oct 1992
Based on a constant v version by Dave Hale.
Trace header fields accessed: ns, dt, delrt, d2
Trace header fields modified: ns, dt, delrt
User's notes (Juan Lorenzo) untested
CHANGES and their DATES
Import packages
instantiation of packages
Encapsulated hash of private variables
sub Step
collects switches and assembles bash instructions by adding the program name
sub note
collects switches and assembles bash instructions by adding the program name
sub clear
sub Q
sub ceil
sub dt
sub dtau
sub dx
sub ft
sub ftau
sub ntau
sub tmig
sub tmpdir
sub verbose
sub vfile
sub vmig
sub get_max_index
max index = number of input variables -1