What’s New in Photutils 1.5?#
Smoothing data prior to source detection and deblending#
The kernel keyword was deprecated from the
detect_sources and
deblend_sources functions. Instead the user
should create a (background-subtracted) convolved image and input it
directly into these functions. Doing so improves the overall performance
by omitting extra convolution steps within each function or class. Both
the (background subtracted) unconvolved and convolved images should be
input into the SourceCatalog class.
A make_2dgaussian_kernel convenience function
was added for creating 2D Gaussian kernels.
New SourceFinder class#
A new SourceFinder
convenience class was added, combining source detection and
deblending. The detect_sources and
deblend_sources functions also still remain
available. The separate tools can be used, for example, to effienciently
explore the various deblending parameters.
Source Deblending Performance Improvements#
The performance of the deblend_sources
has been significantly improved. Also,
deblend_sources and
SourceFinder now have a nproc keyword to
enable multiprocessing during source deblending. Please note that due
to overheads, multiprocessing may be slower than serial processing.
This is especially true if one only has a small number of sources to
deblend. The benefits of multiprocessing require ~1000 or more sources
to deblend, with larger gains as the number of sources increase.
Also, a new sinh multi-thresholding mode was added to
deblend_sources (also available in
the new SourceFinder).
New SegmentationImage methods#
SegmentationImage has a new
make_source_mask method
to create a source mask by dilating the segmentation image with a
user-defined footprint. A new circular_footprint
convenience function was added to create circular footprints.
There is also a new imshow
convenience method for plotting the segmentation image.
SourceCatalog minimum Kron radius#
A minimum value for the unscaled Kron radius can now be specified
as the second element of the kron_params keyword input to
SourceCatalog. The kron_params keyword now
has an optional third item representing the minimum circular radius.
Custom cutouts from SourceCatalog#
The SourceCatalog has a new
make_cutouts method
for making custom-sized image cutouts for each labeled source
centered at their centroid. The cutouts are instances of a new
CutoutImage class.
PSF-Fitting Masks#
The ~photutils.psf.BasicPSFPhotometry,
~photutils.psf.IterativelySubtractedPSFPhotometry and
~photutils.psf.DAOPhotPSFPhotometry PSF-fitting instances now accept
a mask keyword when called with the input data to mask bad pixels.
Invalid data values (i.e., NaN or inf) are now automatically masked
when performing PSF fitting. The Astropy/Scipy fitters do not actually
perform a fit if such invalid values are in the data.
Keyword-only arguments are now required for PSF tools#
Keyword arguments used in the PSF tools must now be explicitly input using the keyword name.
Progress Bars#
The deblend_sources function and the
EPSFBuilder class now have options to use a progress
bar using the new tqdm optional dependency.
Other changes#
Please see the Changelog for the complete list of changes.