package Routines;
#
# implemented functions:
#
#  * find_location ......... find location of data region in spectrum
#

require Exporter;

@EXPORT = qw( find_location );

use PDL;

######################################################################
# find location of data region in spectrum
# call   : &find_location($data)
# return : min ......
#          max ......
#          signal ... 
#          start .... start of data section
#          end ...... end of data section
######################################################################
sub find_location ($)
  {
  my ($data) = @_;

  my $threshold = 0.05;

  my $header = $image->gethdr;

  my $na1 = ${$header}{"NAXIS1"};
  my $na2 = ${$header}{"NAXIS2"};
  my $a1s = int($na1*0.5-5);
  my $a1e = int($na1*0.5+5);

  my $slice = ushort($image->slice(($a1s-1).':'.($a1e-1).',0:'.($na2-1)));

  my $cut = oddmedover($slice);
  my $max = max($cut);
  my $min = min($cut);
  my $signal = $min + $threshold*($max-$min);
  my $cols = which($cut > $signal);
  my $cols = $cols + 1;

  return ($min,$max,$signal,$cols->min,$cols->max);
  }