KPG1_PSFSx

Finds the approximate size of a two-dimensional PSF

Description:

Marginal profiles are formed of the absolute PSF values along both axes. For each axis the maximum and minimum values in the corresponding profile are found. The first and last point at which each profile reaches a specified fraction of its total range is found, and the difference returned as the corresponding PSF size. N.B., it is assumed that the input PSF contains no bad pixels.

Invocation

CALL KPG1_PSFSx( PSF, NPIX, NLIN, WORK, NPW, NLW, FRACT, ILEVEL, XSIZE, YSIZE, STATUS )

Arguments

PSF( NPIX, NLIN ) = ? (Given)
The PSF image.
NPIX = INTEGER (Given)
Number of pixels per line in the PSF image.
NLIN = INTEGER (Given)
Number of lines in the PSF image.
WORK( NPW, NLW ) = ? (Given)
Work space.
NPW = INTEGER (Given)
Number of elements per line in the work array. This should be at least equal to the maximum of NPIX and NLIN.
NLW = INTEGER (Given)
Number of lines in the work array. This should be at least 2.
ILEVEL = INTEGER (Given)
The user information level. If ILEVEL is 2 or more, then the user is told what the calculated sizes are.
FRACT = REAL (Given)
The fraction of the PSF peak amplitude at which the PSF size is determined. It should be positive and less than 0.5. If it is outside this range one sixteenth is used.
XSIZE = INTEGER (Returned)
The width in x of the PSF, in units of pixels.
YSIZE = INTEGER (Returned)
The width in y of the PSF, in units of lines.
STATUS = INTEGER (Given and Returned)
The global status.

Notes: