Description:
Creates an equivalent
noise image by swapping the positions of pairs of pixels taken from an image. This ensures that
structure due to galaxies/stars etc is spread randomly throughout the image but the count value
statistics are retained.
The routine may be used in conjunction with SKEW, SELFC, SELFCW or CORR when searching for
low contrast objects. It provides comparison noise images which may be used to determine the
significance of ’objects’ identified by the other applications.
Usage:
MIXUP IN OUT [SEED]
Parameters:
IN = _NDF (Read)
The name of the NDF that is to be scrambled.
OUT = _NDF (Write)
The name of the NDF data that will be created.
SEED = _INTEGER (Read)
An integer seed value to
use for the random number generator. If a null (!) value is given, the seed is set to a non-repeatable
value determined by the time and the process number. The default value is 2001.
Examples:
mixup
in=ic3374 out=ic3374m
The pixel positions in the input file IC3374 will be scrambled
and the resulting image output as IC3374M. mixup in=ic3374 out=ic3374m seed=!
The
same, except that the random numbers wused to mix up the data will be non-repeatable.