STScI Logo

faradius stsdas.hst_calib.foc.foccs


NAME · USAGE · DESCRIPTION · PARAMETERS · EXAMPLES · BUGS · REFERENCES
SEE_ALSO

NAME

faradius -- Compute a measure of the radius.

USAGE

faradius input output outim

DESCRIPTION

This task computes a measure of the radius of the point spread function (PSF) as an indication of how far each image is out of focus. The fradius task differs from this one in that it computes the radius directly, not using an autocorrelation. The autocorrelation of each row (extracted from a focus image by the fextract task) is computed, the autocorrelation is saved in an output image, and the characteristic radius is computed by taking the average of the radii from pixel [1,1] weighted by the autocorrelation. The autocorrelation is done separately for each box, and only for pixels closer than the box size to [1,1]; the separate autocorrelations are added to give the result saved in the file named by the outim parameter.

PARAMETERS

input = "" [string]
Name of the input image. The input image is produced by the fextract task.
output = "" [string]
Name of output text file which will contain two values per row: the position of the refoc mirror (read from the input header) and the characteristic radius.
outim = "" [string]
Name of the output image for autocorrelation.
(verbose = yes) [boolean]
Print refoc positions?

Computing the autocorrelation can take some time, so printing the focus position lets you know how far the task has gotten.

EXAMPLES

BUGS

REFERENCES

This task was written by Phil Hodge.

SEE ALSO

fradius, fsquares


Source Code · Package Help · Search Form · STSDAS