NAME

     glitches  - remove glitches from seismic data

SYNOPSIS

     glitches [ -Nntap ] [ -Ootap ] [ -bnnbins ] [ -kbnbins  ]  [
     -pdibinl  ] [ -psist ] [ -peiend ] [ -nsnstr ] [ -nenetr ] [
     -rsnrst ] [ -renred ] [ -L ] [ -R ] [ -F ] [ -T ] [ -V  ]  [
     -? ]

DESCRIPTION

     glitches computes record or trace  amplitude  histogram  and
     based  on amplitude limits determined by the end bins of the
     histogram the program does a  threshold  limit  of  all  the
     amplitudes  in the record or trace.  The action is either to
     zero the amplitudes which exceed limits  calculated  by  the
     histogram  analysis,  or  try  to  fix them up using a cubic
     sline interpolation around the killed areas of  each  trace.
     This  procedure  is  quite  robust in that if a false glitch
     (i.e. good data) is found and "healed" the output looks like
     the input.  Of course if many samplea are hit this situation
     will degrade as the cubic spline routine has  a  harder  and
     harder time reconstructing the data.

     The user specifies the number of bins in the histogram (this
     should  be less than the total number of samples per trace).
     In the default record mode, the histogram of amplitudes  for
     the  entire  reocrd  is  computed.  The user then sets the %
     limits on the number of killed samples in  each  trace  that
     can  be  tolerated  before  a trace is killed (in which case
     program zombie can be  used).   If  the  histograms  exhibit
     "tails"  containing several bins of bad data multiple passes
     of glitches can be made in a pipeline.

     The actual processing only occurs within the start  and  end
     times, start and end traces, and start and end records.

     glitches gets both its data and its parameters from  command
     line  arguments.  These arguments specify the input, output,
     the application window, the bin specifications, 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).

     -bn nbin
          Enter the number of bins to use.  Default = 100

     -kb kbin
          Enter the number of leftmost and/or rightmost  bins  to
          clip.  Default = 1

     -pd idd
          Enter the maximum % glitchey samples tolerated in  each
          trace.   If this limit is exceeded the trace is killed,
          i.e. declared officially dead with a 30000 static.   If
          this  happens try using zombie.  Setting pd = 100% will
          never declare a trace dead even if all the samples  are
          killed.  Default = 10%

     -ps ist
          Enter the process start time (ms).  The default is  the
          first  sample  of  the  trace.  Data before this sample
          will be passed unprocessed.

     -pe iend
          Enter the process end time (ms).  The  default  is  the
          last  sample of the trace.  Data after this sample will
          be passed unprocessed.

     -ns nstr
          Enter the process start trace number.  The  default  is
          the  first trace of the record.  Data before this trace
          will be passed unprocessed.

     -ne netr
          Enter the process end trace number. The default is  the
          last  trace  of the record.  Data after this trace will
          be passed unprocessed.

     -rs nrst
          Enter process start record number.   Default  value  is
          the  first  record.   Data  before  this record will be
          passed unprocessed.

     -re nred
          Enter process end record number.  Default value is last
          record.   Data  after this record will be passed unpro-
          cessed.

     -L   Enter the command line argument '-L' to kill the ampli-
          tudes  residing in the kbinth left-most bins.  Default,
          i.e. no -L or -R is to treat both left- and  right-most
          bins.

     -R   Enter the command line argument '-R' to kill the ampli-
          tudes  residing in the kbinth right-most bins. Default,
          i.e. no -L or -R is to treat both left- and  right-most
          bins.

     -F   Enter the command line argument '-F' to attempt  a  fix
          of  the  glitchey  areas  in each trace by use of cubic
          spline fitting of the good portions.

     -T   Enter the command line argument '-T' to do all calcula-
          tion  trace-by-trace.  Unless the user really knows the
          data this is more likely to result in good  data  being
          trashed.

     -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.

SEE ALSO

     zombie

BUGS

     unknown

AUTHOR

     Paul Gutowski

COPYRIGHT

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