Name
stcube - cube statistics
Synopsis
stcube [options] <cubes...>
Description
stcube gives basic statistics about each plane in a cube.
It is used to have a quick look at what kind of data is in
the cube.
The display looks like :
FILE flat_h.fits
PLANE MIN MAX MEAN STDEV ENERGY FLUX
0001 36.25 1008.25 203.157 105.928 6.61e+09 2.56e+07
...
MIN is the minimum value found in each plane
MAX is the maximum value found in each plane
MEAN is the mean value found in each plane, i.e.
MEAN = Sum(pix) / nbpix
STDEV is the standard deviation on each plane, i.e.
STDEV = Sum(sqr(pix - meanpix)) (aka square sigma)
ENERGY is the sum of squared pixels, i.e.
ENERGY = Sum(sqr(pix))
AFLUX is the sum of absolute pixel values, i.e.
AFLUX = Sum(abs(pix))
Names are separated by tabulations, values by ASCII
blanks, which is often not the best way to visualize them
on an xterm, but is readable by any ASCII data reading
software (awk, Tcl, MIDAS...).
There is one display for each FITS file given on command
line. stcube accepts jokers on command line :
> stcube *.fits
Options
-b or --badpixmap filename
give a bad pixel map to take into account when com-
puting statistics on the cube.
-m or --median
To perform a search for the median pixel value in
the image only. The algorithm is simple: sort out
all pixel values and return the central pixel. It
is not possible to use this option together with -b
or -z.
-z or --zone 'llx lly urx ury'
To compute statistics only on a rectangular zone in
the images. The zone is specified by giving the
coordinates of its lower left and upper right cor-
ners. Corners are included in the rectangle. The
coordinate system is the one used by FITS, namely
that the lower left pixel in the image is labelled
(1,1), x-axis increasing from left to right, y-axis
increasing from bottom to top.
-s or --stdev <name>
To compute a standard deviation frame (only), with
name <name>. This mode of stcube accepts only one
input file name, which should correspond to the
name of a 3d FITS file or a valid ASCII list (i.e.
a data cube). The input cube is processed to obtain
a frame that is giving the standard deviation of
all pixels along time. If several input names are
provided, only the first one will be taken into
account.
Examples
To compute the standard deviation frame named 'stdev.fits'
from a cube named 'cube.fits', you would use:
> stcube --stdev stdev.fits cube.fits
To compute statistics on the lower left quadrant only of a
256x256 image, you would use:
> stcube --zone '1 1 128 128' image.fits
Files
Files shall all comply with FITS format