Image

This module contains the Image abstract class, with the SDSS and SDSS-LSST class that inherit from it. The Image abstract class is meant to be a base class for future expansion of the code for other sources of images. The SDSS image class should function as a catch all for any source of FITS images, not just SDSS images. All that is needed to use the SDSS image class is a FITS image and a RA, and DEC value to pinpoint the object of interest.

The LSST image class for now only works with SDSS images in a certain folder structure. However, this is provided in order to help any future developers

This package can be extended by sub classing Image and implementing the required methods, and _IMAGE_TYPE.

class pawlikMorphLSST.Image.Image(filename=None)

Abstract base class for images

abstract getHeader()
abstract getImage()
pawlikMorphLSST.Image.readImage(filename: str, ra: float, dec: float, npix=128, header=False)
Helper function that can be used to read images directly without need

to manually create Image class.

Parameters

  • filename (sty) – location of image to read

  • ra (float) – RA, right ascension of object of interest in image

  • dec (float) – DEC, declination of object of interest in image

  • npix (int, optional) – Size of cutout to return from larger image. Default is 128

  • header (bool, optional) – If true return header information as well. Default is False

Returns

  • img (np.ndarray, 2D, float) – Cutout image.

  • If header=True then also returns the header from the FITS file.

class pawlikMorphLSST.Image.sdssImage(*args, **kwargs)

Class for SDSS images, as ingested by standard ‘method’

getHeader() → astropy.io.fits.header.Header

Returns the image header

Returns

self.header – The header for the cutout.

Return type

astropy.io.fits.Header

getImage() → numpy.ndarray

Returns the cutout image

Returns

self.image – The cutout image centered on the view provided in setview.

Return type

np.ndarray, float (2D)

setView(ra=None, dec=None, npix=128)
Get the correct view in larger image, and create the cutout on the

correct view

Parameters

  • ra (float) – RA position

  • dec (float) – DEC position

  • npix (int) – Size to make cutout

class pawlikMorphLSST.Image.lsstImage(*args, **kwargs)

Class for SDSS images ingested via LSST dataButler.

Some metadata not available, this includes wcs, and pixel value conversion information (bscale, bzero etc). Shouldn’t really recreate butler on each image call…

This code is far from the optimal way to read images. https://github.com/LSSTScienceCollaborations/StackClub

The above source maybe of help for future developer.

getHeader()
getImage()
setView(ra, dec, run, camCol, field, filter='r', npix=128)