tweakreg_catalog¶
The tweakreg_catalog
module provides functions for generating catalogs
of sources from images.
- jwst.tweakreg.tweakreg_catalog.make_tweakreg_catalog(model, kernel_fwhm, snr_threshold, sharplo=0.2, sharphi=1.0, roundlo=-1.0, roundhi=1.0, brightest=None, peakmax=None, bkg_boxsize=400)[source]¶
Create a catalog of point-line sources to be used for image alignment in tweakreg.
- Parameters
model (
ImageModel
) – The inputImageModel
of a single image. The input image is assumed to be background subtracted.kernel_fwhm (float) – The full-width at half-maximum (FWHM) of the 2D Gaussian kernel used to filter the image before thresholding. Filtering the image will smooth the noise and maximize detectability of objects with a shape similar to the kernel.
snr_threshold (float) – The signal-to-noise ratio per pixel above the
background
for which to consider a pixel as possibly being part of a source.sharplo (float, optional) – The lower bound on sharpness for object detection.
sharphi (float, optional) – The upper bound on sharpness for object detection.
roundlo (float, optional) – The lower bound on roundness for object detection.
roundhi (float, optional) – The upper bound on roundness for object detection.
brightest (int, None, optional) – Number of brightest objects to keep after sorting the full object list. If
brightest
is set toNone
, all objects will be selected.peakmax (float, None, optional) –
Maximum peak pixel value in an object. Only objects whose peak pixel values are strictly smaller than
peakmax
will be selected. This may be used to exclude saturated sources. By default, whenpeakmax
is set toNone
, all objects will be selected.Warning
DAOStarFinder
automatically excludes objects whose peak pixel values are negative. Therefore, settingpeakmax
to a non-positive value would result in exclusion of all objects.bkg_boxsize (float, optional) – The background mesh box size in pixels.
- Returns
catalog – An astropy Table containing the source catalog.
- Return type
Table