FCL(1)

NAME

     fcl, getlimb - find location of center and radius of limb of
     solar image

SYNOPSIS

     fcl [-qv] [argument= value ...]
     getlimb [-qv] [argument= value ...]

DESCRIPTION

     fcl and getlimb find the center and radius of the "best fit"
     to a circular limb in a solar image.  The limb is defined as
     the location of  the  maximum  gradient  near  pixels  whose
     values  are  approximately  equal  to  frac_thresh times the
     average value in a central square.  Data in right  triangles
     in  the  corners  are ignored.  The only distinction between
     the two programs is in the format of the output.

     The -q option prints out the list of required arguments  and
     their  default  or environmental values, then quits.  The -v
     option sets verbose mode, redirecting history from stdout to
     stderr.

OPTIONS

     in=name             The dataset name of the input.

     frac_lenside=float  size  of  ignored   triangles   (default
                         70/1024).

     frac_box=float      size  of  central  box  for  determining
                         threshold (default 200/1024).

     frac_thresh=float   threshold multiplier (default 0.3).

EXAMPLES

     fcl in= /scr24/phil/optest/oct508/lev1/V_mdi/V_mdi.048.fits
     produces the output:
     xc = 132.426, yc = 143.998, radius = 114.626

     getlimb                                                  in=
     /scr24/phil/optest/oct508/lev1/V_mdi/V_mdi.048.fits
     produces the output:
     RMAJOR=114.626 X0=132.426 Y0=143.998

FILES

SEE ALSO

DIAGNOSTICS

BUGS

     There is no good reason for  having  two  separate  programs
     simply  to  provide  output strings in different formats.  A
     flag would suffice, if the formats were essential.

     Only works for square data arrays.  The threshold and corner
     zeroing parameters should not have to be supplied.

AUTHOR

     Lyle Bacon, based on a routine by Cliff Toner  as  inherited
     through Robert Ronan

HISTORY

     1994-02-14     SOI Version 0.8