NAME
slicetrp - take time slices (or seismic records) and
interpolate interior dead cells
SYNOPSIS
slicetrp [ -Nntap ] [ -Ootap ] [ -iternum ] [ [ -nP ] [ -P ]
[ -x1x1 ] [ -y1y1 ] [ -x2x2 ] [ -y2y2 ] [ -x3x3 ] [ -y3y3 ]
[ -x4x4 ] [ -y4y4 ] [ -cldmcldm ] [ -ildmildm ] ] [ -V ] [
-? ]
DESCRIPTION
slicetrp will interpolate interior dead cells of each input
X-Y time slice using a sameness search algorithm. This
algorithm looks at the sign of samples around the sample to
be interpolated and averages the set of samples with the
same sign. If more than one set have the same sign then the
maximum amplitude is used to further decide on the make up
of the average. A scematic of the star search is
xt -- - -- yt
x -- o -- y
xb -- - -- yb
where one of (xt+yb)/2 , (x+y)/2 or (xb+yt)/2 is used
depending on the weighting for sameness which is based on
sign.
For slices that have only isolated dead cells only a single
iteration is necessary; for several contiguous dead cells
more iterations are required to fill in all the zero samples
since the results of each iteration are passed on to the
next. If there are large holes in the data then this scheme
will not be able to infill properly. Testing on a represen-
tative slice is recommended.
slicetrp can be run twice for a given flow: the first run is
done on time slice data and does the actual interpolation;
the second post-process run is done after the data have been
transposed back to LI/DI orientation and takes care of the
headers of the interpolated cells. Only those cells that
were zero for all input time slices will be affected by the
second post process run. This post interpolation run is
optional and this funcrionality can be duplicated using
codes like li_di.
The downstream slicetrp needs to know what cells were dead
on input so the first slicetrp sacrifices the last time
slice (last sample of every trace) to store a 30000 in each
sample corresponding to a dead cell and zero everywhere
else. The default is to fix up the LI and DI numbering of
the formerly dead traces. If the survey coordinates are pro-
vided the CDPBCX & CDPBCY will also be reconstructed.
slicetrp gets both its data and its parameters from command
line arguments. These arguments specify the input, output,
number of iterations, and verbose printout, if desired.
Command line arguments
-N ntap
Enter the input data set name or file immediately after
typing -N unless the input is from a pipe in which case
the -N entry must be omitted. This input file should
include the complete path name if the file resides in a
different directory. Example -N/b/vsp/dummy tells the
program to look for file 'dummy' in directory '/b/vsp'.
-O otap
Enter the output data set name or file immediately
after typing -O. This output file is not required when
piping the output to another process. The output data
set also requires the full path name (see above).
-iter num
Pre-process phase: enter the desired number of itera-
tions. Default value is 3.
-nP No post-process phase: records will be processed and
output with no attempt made to determine dead cells
(see post-process -P below). This option can be used
for any input seismic records not just time slices.
-P Post-process phase: enter the command line argument '-
P' to post process the LI/DI transposed data to fix up
trace headers of formerly dead cells. It knows which
cells were dead from the upstream run of slicetrp
because the very last time slice was sacrificed to
store a 30000 value at each sample corresponding to a
dead cell - all other samples being set to zero. After
transposing the data this time slice is the last sample
of every trace. Reasonable LI & DI numbers are put into
the formerly dead trace headers based on LI & DI incre-
ments of one
x4, y4]
-x1, -y1, -x2, -y2, -x3, -y3, -x4, -
y4 [x1, y1, x2, y2, x3, y3,
Post-process phase optional input (to fill in CDPBCX &
CDPBCY): Enter the area of interest over the survey
with the X-Y coordinates (ft,m) defining the four
corners of a parallelogram on the ground. Corner 1 is
always defined to be the northeast corner. Going either
clockwise or counter clockwise (clockwise recommended)
from Corner 1 the first move to Corner 2 should be in
the direction of a receiver or shot line. The origin
will always be defined to be the lower left (corner 3)
of the survey. The values must be the same units as
those given in the source, receiver, and midpoint X-Ys
in the trace headers.
-cldm cldm
Post-process phase optional input (to fill in CDPBCX &
CDPBCY): Enter the crossline (along X or side 2-3) cell
dimension (ft,m). For most shooting geometries this
will be 1/2 the line or group spacing depending on the
orientation of side 2-3 with respect to the receiver
lines. The sides are defined to be X along side 1-4
(roughly cross-line direction), Y along side 1-2
(roughly in-line direction). Remember when setting up
the coordinate system the line joining Corner (1) to
Corner (2) should be in the direction of a receiver or
shot line. No default.
-ildm ildm
Post-process phase optional input (to fill in CDPBCX &
CDPBCY): Enter the inline (along Y or side 1-2) cell
dimension (ft,m). For most recording geometries this
will be 1/2 the line or group spacing depending on the
orientation of side 1-2 with respect to the receiver
lines. The sides are defined to be X along side 1-4
(roughly cross-line direction), Y along side 1-2
(roughly in-line direction). Remember when setting up
the coordinate system the line joining Corner (1) to
Corner (2) should be in the direction of a receiver or
shot line. No default.
-V Enter the command line argument '-V' to get additional
printout.
-? Enter the command line argument '-?' or -h to get
online help. The program terminates after the help
screen is printed.
EXAMPLE
Suppose the input file junkin is an LI oriented data set
that has dead cells. The flow to do the interpolation might
look like
ttds3d -Njunkin -NDtxy -ODxyt -M16 -Ttmp1 |
slicetrp |
ttds3d -NDxyt -ODtxy -M16 -Ttmp2 |
hdrswap -N2junkin |
slicetrp -Ojunko -P
where the ttds3d steps have been set up for the suns (16mb
memory) and the the temporary files tmp1 and tmp2 are
created in the current working directory. The hdrswap has
picked up the original trace headers (destroyed by the tran-
sposition of the input data). The post-process phase (second
slicetrp step) only reconstructs LI & DI numbers of the
formerly dead traces.
BUGS
unknown
SEE ALSO
gentrp spacetrp
AUTHOR
Paul Gutowski cadged from program zombie by P.G.A. Garossino
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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