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-rw-r--r--stwcs/updatewcs/det2im.py299
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diff --git a/stwcs/updatewcs/det2im.py b/stwcs/updatewcs/det2im.py
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+from __future__ import absolute_import, division # confidence high
+
+import numpy as np
+from astropy.io import fits
+from stsci.tools import fileutil
+
+from . import utils
+
+import logging, time
+logger = logging.getLogger('stwcs.updatewcs.d2im')
+
+class DET2IMCorr(object):
+ """
+ Defines a Lookup table prior distortion correction as per WCS paper IV.
+ It uses a reference file defined by the D2IMFILE (suffix 'd2im') keyword
+ in the primary header.
+
+ Notes
+ -----
+ - Using extensions in the reference file create a WCSDVARR extensions
+ and add them to the science file.
+ - Add record-valued keywords to the science extension header to describe
+ the lookup tables.
+ - Add a keyword 'D2IMEXT' to the science extension header to store
+ the name of the reference file used to create the WCSDVARR extensions.
+
+ If WCSDVARR extensions exist and `D2IMFILE` is different from `D2IMEXT`,
+ a subsequent update will overwrite the existing extensions.
+ If WCSDVARR extensions were not found in the science file, they will be added.
+
+ """
+
+ def updateWCS(cls, fobj):
+ """
+ Parameters
+ ----------
+ fobj: `astropy.io.fits.HDUList` object
+ Science file, for which a distortion correction in a NPOLFILE is available
+
+ """
+ logger.info("\n\tStarting DET2IM: %s" %time.asctime())
+ try:
+ assert isinstance(fobj, fits.HDUList)
+ except AssertionError:
+ logger.exception('\n\tInput must be a fits.HDUList object')
+ raise
+
+ cls.applyDet2ImCorr(fobj)
+ d2imfile = fobj[0].header['D2IMFILE']
+
+ new_kw = {'D2IMEXT': d2imfile}
+ return new_kw
+
+ updateWCS = classmethod(updateWCS)
+
+ def applyDet2ImCorr(cls, fobj):
+ """
+ For each science extension in a fits file object:
+ - create a WCSDVARR extension
+ - update science header
+ - add/update D2IMEXT keyword
+ """
+ d2imfile = fileutil.osfn(fobj[0].header['D2IMFILE'])
+ # Map D2IMARR EXTVER numbers to FITS extension numbers
+ wcsdvarr_ind = cls.getWCSIndex(fobj)
+ d2im_num_ext = 1
+ for ext in fobj:
+ try:
+ extname = ext.header['EXTNAME'].lower()
+ except KeyError:
+ continue
+ if extname == 'sci':
+ extversion = ext.header['EXTVER']
+ ccdchip = cls.get_ccdchip(fobj, extname='SCI', extver=extversion)
+ header = ext.header
+ # get the data arrays from the reference file
+ dx, dy = cls.getData(d2imfile, ccdchip)
+ # Determine EXTVER for the D2IMARR extension from the D2I file (EXTNAME, EXTVER) kw.
+ # This is used to populate DPj.EXTVER kw
+ for ename in zip(['DX', 'DY'], [dx, dy]):
+ if ename[1] is not None:
+ error_val = ename[1].max()
+ cls.addSciExtKw(header, wdvarr_ver=d2im_num_ext, d2im_extname=ename[0], error_val=error_val)
+ hdu = cls.createD2ImHDU(header, d2imfile=d2imfile,
+ wdvarr_ver=d2im_num_ext,
+ d2im_extname=ename[0],
+ data=ename[1],ccdchip=ccdchip)
+ if wcsdvarr_ind and d2im_num_ext in wcsdvarr_ind:
+ fobj[wcsdvarr_ind[d2im_num_ext]] = hdu
+ else:
+ fobj.append(hdu)
+ d2im_num_ext = d2im_num_ext + 1
+ applyDet2ImCorr = classmethod(applyDet2ImCorr)
+
+ def getWCSIndex(cls, fobj):
+
+ """
+ If fobj has WCSDVARR extensions:
+ returns a mapping of their EXTVER kw to file object extension numbers
+ if fobj does not have WCSDVARR extensions:
+ an empty dictionary is returned
+ """
+ wcsd = {}
+ for e in range(len(fobj)):
+ try:
+ ename = fobj[e].header['EXTNAME']
+ except KeyError:
+ continue
+ if ename == 'D2IMARR':
+ wcsd[fobj[e].header['EXTVER']] = e
+ logger.debug("A map of D2IMARR extensions %s" % wcsd)
+ return wcsd
+
+ getWCSIndex = classmethod(getWCSIndex)
+
+ def addSciExtKw(cls, hdr, wdvarr_ver=None, d2im_extname=None, error_val=0.0):
+ """
+ Adds kw to sci extension to define WCSDVARR lookup table extensions
+
+ """
+ if d2im_extname =='DX':
+ j=1
+ else:
+ j=2
+
+ d2imerror = 'D2IMERR%s' %j
+ d2imdis = 'D2IMDIS%s' %j
+ d2imext = 'D2IM%s.' %j + 'EXTVER'
+ d2imnaxes = 'D2IM%s.' %j +'NAXES'
+ d2imaxis1 = 'D2IM%s.' %j+'AXIS.1'
+ d2imaxis2 = 'D2IM%s.' %j+'AXIS.2'
+ keys = [d2imerror, d2imdis, d2imext, d2imnaxes, d2imaxis1, d2imaxis2]
+ values = {d2imerror: error_val,
+ d2imdis: 'Lookup',
+ d2imext: wdvarr_ver,
+ d2imnaxes: 2,
+ d2imaxis1: 1,
+ d2imaxis2: 2}
+
+ comments = {d2imerror: 'Maximum error of NPOL correction for axis %s' % j,
+ d2imdis: 'Detector to image correction type',
+ d2imext: 'Version number of WCSDVARR extension containing d2im lookup table',
+ d2imnaxes: 'Number of independent variables in d2im function',
+ d2imaxis1: 'Axis number of the jth independent variable in a d2im function',
+ d2imaxis2: 'Axis number of the jth independent variable in a d2im function'
+ }
+ # Look for HISTORY keywords. If present, insert new keywords before them
+ before_key = 'HISTORY'
+ if before_key not in hdr:
+ before_key = None
+
+ for key in keys:
+ hdr.set(key, value=values[key], comment=comments[key], before=before_key)
+
+ addSciExtKw = classmethod(addSciExtKw)
+
+ def getData(cls,d2imfile, ccdchip):
+ """
+ Get the data arrays from the reference D2I files
+ Make sure 'CCDCHIP' in the npolfile matches "CCDCHIP' in the science file.
+ """
+ xdata, ydata = (None, None)
+ d2im = fits.open(d2imfile)
+ for ext in d2im:
+ d2imextname = ext.header.get('EXTNAME',"")
+ d2imccdchip = ext.header.get('CCDCHIP',1)
+ if d2imextname == 'DX' and d2imccdchip == ccdchip:
+ xdata = ext.data.copy()
+ continue
+ elif d2imextname == 'DY' and d2imccdchip == ccdchip:
+ ydata = ext.data.copy()
+ continue
+ else:
+ continue
+ d2im.close()
+ return xdata, ydata
+ getData = classmethod(getData)
+
+ def createD2ImHDU(cls, sciheader, d2imfile=None, wdvarr_ver=1,
+ d2im_extname=None,data = None, ccdchip=1):
+ """
+ Creates an HDU to be added to the file object.
+ """
+ hdr = cls.createD2ImHdr(sciheader, d2imfile=d2imfile,
+ wdvarr_ver=wdvarr_ver, d2im_extname=d2im_extname,
+ ccdchip=ccdchip)
+ hdu = fits.ImageHDU(header=hdr, data=data)
+ return hdu
+
+ createD2ImHDU = classmethod(createD2ImHDU)
+
+ def createD2ImHdr(cls, sciheader, d2imfile, wdvarr_ver, d2im_extname, ccdchip):
+ """
+ Creates a header for the D2IMARR extension based on the D2I reference file
+ and sci extension header. The goal is to always work in image coordinates
+ (also for subarrays and binned images). The WCS for the D2IMARR extension
+ is such that a full size d2im table is created and then shifted or scaled
+ if the science image is a subarray or binned image.
+ """
+ d2im = fits.open(d2imfile)
+ d2im_phdr = d2im[0].header
+ for ext in d2im:
+ try:
+ d2imextname = ext.header['EXTNAME']
+ d2imextver = ext.header['EXTVER']
+ except KeyError:
+ continue
+ d2imccdchip = cls.get_ccdchip(d2im, extname=d2imextname, extver=d2imextver)
+ if d2imextname == d2im_extname and d2imccdchip == ccdchip:
+ d2im_header = ext.header
+ break
+ else:
+ continue
+ d2im.close()
+
+ naxis = d2im[1].header['NAXIS']
+ ccdchip = d2imextname
+
+ kw = { 'NAXIS': 'Size of the axis',
+ 'CDELT': 'Coordinate increment along axis',
+ 'CRPIX': 'Coordinate system reference pixel',
+ 'CRVAL': 'Coordinate system value at reference pixel',
+ }
+
+ kw_comm1 = {}
+ kw_val1 = {}
+ for key in kw.keys():
+ for i in range(1, naxis+1):
+ si = str(i)
+ kw_comm1[key+si] = kw[key]
+
+ for i in range(1, naxis+1):
+ si = str(i)
+ kw_val1['NAXIS'+si] = d2im_header.get('NAXIS'+si)
+ kw_val1['CDELT'+si] = d2im_header.get('CDELT'+si, 1.0) * sciheader.get('LTM'+si+'_'+si, 1)
+ kw_val1['CRPIX'+si] = d2im_header.get('CRPIX'+si, 0.0)
+ kw_val1['CRVAL'+si] = (d2im_header.get('CRVAL'+si, 0.0) - \
+ sciheader.get('LTV'+str(i), 0))
+ kw_comm0 = {'XTENSION': 'Image extension',
+ 'BITPIX': 'IEEE floating point',
+ 'NAXIS': 'Number of axes',
+ 'EXTNAME': 'WCS distortion array',
+ 'EXTVER': 'Distortion array version number',
+ 'PCOUNT': 'Special data area of size 0',
+ 'GCOUNT': 'One data group',
+ }
+
+ kw_val0 = { 'XTENSION': 'IMAGE',
+ 'BITPIX': -32,
+ 'NAXIS': naxis,
+ 'EXTNAME': 'D2IMARR',
+ 'EXTVER': wdvarr_ver,
+ 'PCOUNT': 0,
+ 'GCOUNT': 1,
+ 'CCDCHIP': ccdchip,
+ }
+ cdl = []
+ for key in kw_comm0.keys():
+ cdl.append((key, kw_val0[key], kw_comm0[key]))
+ for key in kw_comm1.keys():
+ cdl.append((key, kw_val1[key], kw_comm1[key]))
+ # Now add keywords from NPOLFILE header to document source of calibration
+ # include all keywords after and including 'FILENAME' from header
+ start_indx = -1
+ end_indx = 0
+ for i, c in enumerate(d2im_phdr):
+ if c == 'FILENAME':
+ start_indx = i
+ if c == '': # remove blanks from end of header
+ end_indx = i+1
+ break
+ if start_indx >= 0:
+ for card in d2im_phdr.cards[start_indx:end_indx]:
+ cdl.append(card)
+
+ hdr = fits.Header(cards=cdl)
+
+ return hdr
+
+ createD2ImHdr = classmethod(createD2ImHdr)
+
+ def get_ccdchip(cls, fobj, extname, extver):
+ """
+ Given a science file or npol file determine CCDCHIP
+ """
+ ccdchip = 1
+ if fobj[0].header['INSTRUME'] == 'ACS' and fobj[0].header['DETECTOR'] == 'WFC':
+ ccdchip = fobj[extname, extver].header['CCDCHIP']
+ elif fobj[0].header['INSTRUME'] == 'WFC3' and fobj[0].header['DETECTOR'] == 'UVIS':
+ ccdchip = fobj[extname, extver].header['CCDCHIP']
+ elif fobj[0].header['INSTRUME'] == 'WFPC2':
+ ccdchip = fobj[extname, extver].header['DETECTOR']
+ elif fobj[0].header['INSTRUME'] == 'STIS':
+ ccdchip = fobj[extname, extver].header['DETECTOR']
+ elif fobj[0].header['INSTRUME'] == 'NICMOS':
+ ccdchip = fobj[extname, extver].header['CAMERA']
+ return ccdchip
+
+ get_ccdchip = classmethod(get_ccdchip)
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