SourceCatalogStep

class romancal.source_catalog.SourceCatalogStep(name=None, parent=None, config_file=None, _validate_kwds=True, **kws)[source]

Bases: RomanStep

Create a catalog of sources including photometry and basic shape measurements.

Parameters:

  • input (str, ImageModel, or MosaicModel) – Path to an ASDF file, or an ImageModel or MosaicModel.

  • bkg_boxsize (int, optional) – Edge length, in pixels, of the square mesh boxes used by Background2D to estimate the global 2D background.

  • kernel_fwhm (float, optional) – Full-width-at-half-maximum, in pixels, of the Gaussian smoothing kernel used for source detection.

  • snr_threshold (float, optional) – Per-pixel signal-to-noise ratio above the background required for a pixel to be considered part of a source.

  • npixels (int, optional) – Minimum number of connected pixels above snr_threshold required for a detection to be retained as a source.

  • deblend (bool, optional) – If True, deblend overlapping sources after detection.

  • suffix (str, optional) – Suffix appended to the output filenames. Default 'cat'.

  • fit_psf (bool, optional) – If True, fit source PSFs.

  • forced_segmentation (str, optional) – If non-empty, path to a pre-computed segmentation image to use in place of fresh source detection (forced photometry mode).

Create a Step instance.

Parameters:

  • name (str) – The name of the Step instance. Used in logging messages and in cache filenames. If not provided, one will be generated based on the class name.

  • parent (Step) – The parent step of this step. Used to determine a fully-qualified name for this step, and to determine the mode in which to run this step.

  • config_file (str or pathlib.Path) – The path to the config file that this step was initialized with. Use to determine relative path names of other config files.

  • _validate_kwds (bool) – Validate given kws against specs/config.

  • **kws (dict) – Additional parameters to set. These will be set as member variables on the new Step instance.

Attributes Summary

class_alias

reference_file_types

spec

Methods Summary

process(dataset)

This is where real work happens.

Attributes Documentation

class_alias = 'source_catalog'
reference_file_types: ClassVar = ['apcorr']
spec
bkg_boxsize = integer(default=1000)   # background mesh box size in pixels
kernel_fwhm = float(default=2.0)      # Gaussian kernel FWHM in pixels
snr_threshold = float(default=3.0)    # per-pixel SNR threshold above the bkg
npixels = integer(default=25)         # min number of pixels in source
deblend = boolean(default=False)      # deblend sources?
suffix = string(default='cat')        # Default suffix for output files
fit_psf = boolean(default=True)       # fit source PSFs for accurate astrometry?
forced_segmentation = string(default='')  # force the use of this segmentation map

Methods Documentation

process(dataset)[source]

This is where real work happens. Every Step subclass has to override this method. The default behaviour is to raise a NotImplementedError exception.