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sub2full

Given an image specified by the user which contains a subarray readout, return the location of the corner of the subarray in a full frame reference image (including the full physical extent of the chip), in 1-indexed pixels. If the user supplies an X and Y coordinate, then the translated location of that point will be returned.

../_static/sub2full_translate.png

Usage

from wfc3tools import sub2full
coords=sub2full(filename,x=None, y=None,fullExtent=False)

Parameters

  • filename [file]
    Input image name or list of image names. The rootname will be used to find the _SPT files in the same directory, the SPT file has all the necessary information for the transform.
  • x = None [integer] Optional
    Specify an x coordinate in the subarray to translate. If an x and y are specified, the fullExtent option is turned off and only the translated x,y coords are returned
  • y = None [integer] Optional
    Specify a y coordinate in the subarray to translate. If an x and y are specified, the fullExtent option is turned off and only the translated x,y coords are returned
  • fullExtent = False [bool] Optional
    If set, the returned values will include the full extent of the subarray in the reference image, for example: (x0,x1,y0,y1)

Returns

A list of tuples which specify the translated coordinates, either (x0,y0) for each image or the full extent sections

Example Output

Default output:

> sub2full('ibbso1fdq_flt.fits')
> [(3584.0, 1539)]

Optional output:

Specify a list of images:

>im = ['ic5p02e0q_spt.fits',
       'ic5p02e1q_spt.fits',
       'ic5p02e2q_spt.fits',
       'ic5p02e3q_spt.fits',
       'ic5p02e4q_spt.fits']
>
> sub2full(im)
> [(1062.0, 1363),
> (1062.0, 1363),
> (1410.0, 1243),
> (1410.0, 1243),
> (1402.0, 1539)]


Return the full extent of the subarray:

> sub2full('ibbso1fdq_flt.fits',fullExtent=True)
> [(3584.0, 4096, 1539, 2050)]

More information on header keywords

The task uses header keywords from the SPT file of the associated image in order to calculate the offset for the subarray. The keywords it uses are:

Keyword Meaning
SS_DTCTR To get the detector for the image
SS_SUBAR To make sure the image is a subarray
XCORNER The x corner of the subarray
YCORNER The y corner of the subarray
NUMROWS Subarray x size
NUMCOLS Subarray y size

The UVIS full frame detector has 2051 rows, with 25 pixels of serial overscan. The IR detector has 1024 rows and 5 pixels of overscan.