NAME

     fkstrip  - attenuate/enhance flat events

SYNOPSIS

     fkstrip [ -Nntap ] [ -Ootap ] [ -nsnstr  ]  [  -nenetr  ]  [
     -rsnrst  ]  [  -renred  ]  [  -siwst ] [ -eiwed ] [ -bwb ] [
     -hwstrwrd ] [ -llsf ] [ -wex ] [ -iaint ] [ -titapr ] [ -P ]
     [ -V ] [ -? ]

DESCRIPTION

     fkstrip attenuates or enhances flat events on  a  record-by-
     record  basis  using  a bessel filter approach.  This can be
     extremely useful for removal of noise and multiples.  Linear
     noise  can  be  removed  by  flattening the noise with vred,
     using fkstrip, then unflattening.  Multiples may be attacked
     by  applying anmo with the multiple velocity, using fkstrip,
     then removing the moveout

     fkstrip gets both its data and its parameters  from  command
     line  arguments.  These arguments specify the input, output,
     the start and end records and traces, start  and  end  times
     for processing, filter length, weighting, tapering, and ver-
     bose printout, if desired.

     Note:  there should be at least as many traces per record as
     there  are  filter points lsf.  If there are not the program
     will attempt to adjust the trace reading to conform to this;
     an  alternative  is  to use utop with -L and -R command line
     entries to force the data to conform  to  this  restriction.
     After  fkstrip  has been applied to the modified header data
     the reverse utop should be applied .  All this can  be  done
     in a pipeline, naturally.

  Command line arguments
     -N ntap
          Enter the input data set name or file immediately after
          typing  -N.   If piping in this command line entry will
          be omitted.  The 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).

     -ns nstr
          Enter the process start trace  number.   Trace  numbers
          below this value will not be processed.  The default is
          1.

     -ne netr
          Enter the process  end  trace  number.   Trace  numbers
          above this value will not be processed.  The default is
          the last trace number on the input data set.

     -rs nrst
          Enter process start record number. Record numbers below
          this value will not be processed.  Default value is the
          first record.

     -re nred
          Enter end process record number. Record  numbers  above
          this  value  will  not  be processed.  Default value is
          last record.

     -s iwst
          Enter start time for processing.  Before this time  the
          data  will  be untouched by the filter.  Default is the
          start of the trace.  See -b[] option below as an alter-
          native start time.

     -e iwed
          Enter end time for processing.   After  this  time  the
          data  will  be untouched by the filter.  Default is the
          end of the trace.

     -b wb
          Enter optional water bottom start time multiplier.  The
          start  time  is  computed by averaging the water depths
          over the current record (the value associated with  the
          WDepDP  trace  header  mnemonic),  dividing this by the
          water velocity (line header word WatVel), and multiply-
          ing  the result by the b factor.  The end time is given
          by -e[] above.  Default = 0.0 (i.e. do  not  use  water
          bottom option)

     -hw strwrd
          Enter optional application  window  time  trace  header
          word.  The  times  are  pulled from the live traces for
          each gather then averaged to give a window time for the
          whole  gather.   The application start time is the -s[]
          subtracted from the window time;  the  application  end
          time  is  the  window time plus -e[]. Using this option
          causes the water bottom start time option to be ignored
          and no scaling is applied to the start time. Default is
          to ignore trace header window times.

     -l lsf
          Enter filter length in points.  Default length is 31

     -w ex
          Enter bessel weighting  factor.   Default  is  0  which
          results in a very deep sharp notch.  By increasing this
          value the filter becomes more stable  (fewer  potential
          ringing  problems)  but  at the cost of less rejection.
          Values are usually in the range 0.0 - 3.0

     -i aint
          Enter filter intercept.  Default is .05

     -t itapr
          Enter number of traces either side of spread to  taper.
          This  will  be  applied  to  both  sides so the maximum
          allowed is 1/2  Default is 0

     -P   Enter the command line argument '-P' to enhance  rather
          than attenuate flat dips

     -V   Enter the command line argument '-V' to get  additional
          printout.

     -?   Enter the command line  argument  '-?'  to  get  online
          help.   The program terminates after the help screen is
          printed.

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.