diff options
Diffstat (limited to 'updatewcs/det2im.py')
| -rw-r--r-- | updatewcs/det2im.py | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/updatewcs/det2im.py b/updatewcs/det2im.py new file mode 100644 index 0000000..90c9f28 --- /dev/null +++ b/updatewcs/det2im.py @@ -0,0 +1,155 @@ +import pyfits +from pytools import fileutil + +class DET2IMCorr(object): + def updateWCS(cls, fobj): + """ + :Parameters: + `fobj`: pyfits object + Science file, for which a detector to image correction + is available + + """ + assert isinstance(fobj, pyfits.NP_pyfits.HDUList) + + d2imfile = fobj[0].header['D2IMFILE'] + axiscorr = cls.getAxisCorr(d2imfile) + d2imerr = pyfits.getdata(d2imfile, ext=1).max() + if axiscorr == None: + new_kw = {} + else: + new_kw = {'D2IMEXT': d2imfile, 'AXISCORR': axiscorr, 'D2IMERR': d2imerr} + cls.applyDet2ImCorr(fobj, axiscorr) + cls.updatehdr(fobj, new_kw) + + updateWCS = classmethod(updateWCS) + + def getAxisCorr(cls, refname): + try: + direction = pyfits.getval(refname, ext=1, key='EXTNAME') + if direction == 'DX': return 1 + elif direction == 'DY': return 2 + else: + print '\tDET2IM correction expects the reference file to have' + print '\tan EXTNAME keyword of value "DX" or "DY"' + return None + except AttributeError: + print "\tAxis to which to apply the detector to image " + print "\tcorrection cannot be determined because the reference " + print "\tfile %s is missing a keyword EXTNAME" % refname + direction = None + return direction + getAxisCorr = classmethod(getAxisCorr) + + def applyDet2ImCorr(cls,fobj, axiscorr): + d2imfile = fileutil.osfn(fobj[0].header['D2IMFILE']) + hdu = cls.createDgeoHDU(d2imfile, axiscorr) + d2imarr_ind = cls.getD2imIndex(fobj) + if d2imarr_ind: + fobj[d2imarr_ind] = hdu + else: + fobj.append(hdu) + applyDet2ImCorr = classmethod(applyDet2ImCorr) + + def getD2imIndex(cls,fobj): + index = None + for e in range(len(fobj)): + try: + ename = fobj[e].header['EXTNAME'] + except KeyError: + continue + if ename == 'D2IMARR': + index = e + return index + getD2imIndex = classmethod(getD2imIndex) + + def createDgeoHDU(cls, d2imfile, axiscorr): + + d2im_data = pyfits.getdata(d2imfile, ext=1) + d2im_hdr = cls.createDet2ImHdr(d2im_data.shape, axiscorr) + hdu = pyfits.ImageHDU(header=d2im_hdr, data=d2im_data) + + return hdu + + createDgeoHDU = classmethod(createDgeoHDU) + + def createDet2ImHdr(cls, data_shape, axiscorr): + """ + Creates a header for the D2IMARR extension based on the + reference file recorded in D2IMFILE keyword in the primary header. + """ + + naxis1 = data_shape[0] + naxis2 = 0 + crpix1 = 0.0 + crpix2 = 0.0 + cdelt1 = 1.0 + cdelt2 = 1.0 + crval1 = 0.0 + crval2 = 0.0 + keys = ['XTENSION','BITPIX','NAXIS','NAXIS1','NAXIS2', + 'EXTNAME','EXTVER','PCOUNT','GCOUNT','CRPIX1', + 'CDELT1','CRVAL1','CRPIX2','CDELT2','CRVAL2', 'AXISCORR'] + + comments = {'XTENSION': 'Image extension', + 'BITPIX': 'IEEE floating point', + 'NAXIS': 'Number of axes', + 'NAXIS1': 'Number of image columns', + 'NAXIS2': 'Number of image rows', + 'EXTNAME': 'WCS distortion array', + 'EXTVER': 'Distortion array version number', + 'PCOUNT': 'Special data area of size 0', + 'GCOUNT': 'One data group', + 'CRPIX1': 'Distortion array reference pixel', + 'CDELT1': 'Grid step size in first coordinate', + 'CRVAL1': 'Image array pixel coordinate', + 'CRPIX2': 'Distortion array reference pixel', + 'CDELT2': 'Grid step size in second coordinate', + 'CRVAL2': 'Image array pixel coordinate', + 'AXISCORR': 'Direction in which the det2im correction is applied'} + + values = {'XTENSION': 'IMAGE', + 'BITPIX': -32, + 'NAXIS': 1, + 'NAXIS1': naxis1, + 'NAXIS2': naxis2, + 'EXTNAME': 'D2IMARR', + 'EXTVER': 1, + 'PCOUNT': 0, + 'GCOUNT': 1, + 'CRPIX1': crpix1, + 'CDELT1': cdelt1, + 'CRVAL1': crval1, + 'CRPIX2': crpix2, + 'CDELT2': cdelt2, + 'CRVAL2': crval2, + 'AXISCORR': axiscorr + } + + + cdl = pyfits.CardList() + for c in keys: + cdl.append(pyfits.Card(key=c, value=values[c], comment=comments[c])) + + hdr = pyfits.Header(cards=cdl) + return hdr + + createDet2ImHdr = classmethod(createDet2ImHdr) + + def updatehdr(cls, fobj, kwdict): + """ + Update extension headers to keep record of the files used for the + detector to image correction. + """ + for ext in fobj: + try: + extname = ext.header['EXTNAME'].lower() + except KeyError: + continue + if extname == 'sci': + for kw in kwdict: + ext.header.update(kw, kwdict[kw]) + else: + continue + updatehdr = classmethod(updatehdr) +
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