tweakreg_step¶
The tweakreg_step
function (class name TweakRegStep
)
is the top-level function used to call the “tweakreg” operation
from the JWST calibration pipeline.
JWST pipeline step for image alignment.
- Authors
Mihai Cara
- class jwst.tweakreg.tweakreg_step.TweakRegStep(name=None, parent=None, config_file=None, _validate_kwds=True, **kws)[source]¶
TweakRegStep: Image alignment based on catalogs of sources detected in input images.
Create a
Step
instance.- Parameters
name (str, optional) – 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 instance, optional) – 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 path, optional) – The path to the config file that this step was initialized with. Use to determine relative path names of other config files.
**kws (dict) – Additional parameters to set. These will be set as member variables on the new Step instance.
- class_alias = 'tweakreg'¶
- process(input)[source]¶
This is where real work happens. Every Step subclass has to override this method. The default behaviour is to raise a NotImplementedError exception.
- reference_file_types = []¶
- spec = "\n save_catalogs = boolean(default=False) # Write out catalogs?\n use_custom_catalogs = boolean(default=False) # Use custom user-provided catalogs?\n catalog_format = string(default='ecsv') # Catalog output file format\n catfile = string(default='') # Name of the file with a list of custom user-provided catalogs\n kernel_fwhm = float(default=2.5) # Gaussian kernel FWHM in pixels\n snr_threshold = float(default=10.0) # SNR threshold above the bkg\n sharplo = float(default=0.2) # The lower bound on sharpness for object detection.\n sharphi = float(default=1.0) # The upper bound on sharpness for object detection.\n roundlo = float(default=-1.0) # The lower bound on roundness for object detection.\n roundhi = float(default=1.0) # The upper bound on roundness for object detection.\n brightest = integer(default=200) # Keep top ``brightest`` objects\n peakmax = float(default=None) # Filter out objects with pixel values >= ``peakmax``\n bkg_boxsize = integer(default=400) # The background mesh box size in pixels.\n enforce_user_order = boolean(default=False) # Align images in user specified order?\n expand_refcat = boolean(default=False) # Expand reference catalog with new sources?\n minobj = integer(default=15) # Minimum number of objects acceptable for matching\n searchrad = float(default=2.0) # The search radius in arcsec for a match\n use2dhist = boolean(default=True) # Use 2d histogram to find initial offset?\n separation = float(default=1.0) # Minimum object separation in arcsec\n tolerance = float(default=0.7) # Matching tolerance for xyxymatch in arcsec\n xoffset = float(default=0.0), # Initial guess for X offset in arcsec\n yoffset = float(default=0.0) # Initial guess for Y offset in arcsec\n fitgeometry = option('shift', 'rshift', 'rscale', 'general', default='rshift') # Fitting geometry\n nclip = integer(min=0, default=3) # Number of clipping iterations in fit\n sigma = float(min=0.0, default=3.0) # Clipping limit in sigma units\n abs_refcat = string(default='') # Catalog file name or one of: 'GAIADR2' or 'GAIADR1', or None, or ''\n save_abs_catalog = boolean(default=False) # Write out used absolute astrometric reference catalog as a separate product\n abs_minobj = integer(default=15) # Minimum number of objects acceptable for matching when performing absolute astrometry\n abs_searchrad = float(default=6.0) # The search radius in arcsec for a match when performing absolute astrometry\n # We encourage setting this parameter to True. Otherwise, xoffset and yoffset will be set to zero.\n abs_use2dhist = boolean(default=True) # Use 2D histogram to find initial offset when performing absolute astrometry?\n abs_separation = float(default=0.1) # Minimum object separation in arcsec when performing absolute astrometry\n abs_tolerance = float(default=0.7) # Matching tolerance for xyxymatch in arcsec when performing absolute astrometry\n # Fitting geometry when performing absolute astrometry\n abs_fitgeometry = option('shift', 'rshift', 'rscale', 'general', default='rshift')\n abs_nclip = integer(min=0, default=3) # Number of clipping iterations in fit when performing absolute astrometry\n abs_sigma = float(min=0.0, default=3.0) # Clipping limit in sigma units when performing absolute astrometry\n output_use_model = boolean(default=True) # When saving use `DataModel.meta.filename`\n "¶