SUFXDECON - random noise attenuation by
FX-DECONvolution
sufxdecon <stdin >stdout [...]
Required Parameters:
Optional Parameters:
taper=.1 length
of taper
fmin=6.
minimum frequency to process in Hz
(accord to twlen)
fmax=.6/(2*dt) maximum frequency to process in Hz
twlen=entire trace time
window length (minimum 300ms for lower freqs)
ntrw=10 number of
traces in window
ntrf=4 number of traces for filter (smaller
than ntrw)
verbose=0 =1
for diagnostic print
tmpdir= if
non-empty, use the value as a directory path prefix
for
storing temporary files; else, if the CWP_TMPDIR
environment
variable is set, use its value for the path;
else use tmpfile()
Notes: Each trace is transformed to the
frequency domain.
For each frequency, Wiener filtering,
with unity prediction in
space, is used to predict the next sample.
At the end of the process, data is mapped back to t-x domain. ",
Credits:
CWP: Carlos E. Theodoro (10/07/97)
References:
Canales(1984):'Random noise
reduction' 54th. SEGM
Gulunay(1986):'FXDECON and complex
Wiener Predicition
filter' 56th.
SEGM
Galbraith(1991):'Random
noise attenuation by F-X
prediction: a tutorial' 61th. SEGM
Algorithm:
- read
data
- loop over time
windows
- select
data
- FFT (t ->
f)
- loop over space
windows
- select
data
- loop over
frequencies
-
autocorelation
-
matrix problem
-
construct filter
-
filter data
- loop
along space window
-
FFT (f -> t)
-
reconstruct data
- output data
Trace header fields accessed: ns, dt,
d1
Trace header fields modified: