diff options
Diffstat (limited to 'lib/stwcs/updatewcs/det2im.py')
| -rw-r--r-- | lib/stwcs/updatewcs/det2im.py | 94 |
1 files changed, 47 insertions, 47 deletions
diff --git a/lib/stwcs/updatewcs/det2im.py b/lib/stwcs/updatewcs/det2im.py index 5e03f74..b658d53 100644 --- a/lib/stwcs/updatewcs/det2im.py +++ b/lib/stwcs/updatewcs/det2im.py @@ -10,43 +10,43 @@ logger = logging.getLogger('stwcs.updatewcs.Det2IM') class DET2IMCorr(object): """ - Stores a small correction to the detector coordinates as a d2imarr + Stores a small correction to the detector coordinates as a d2imarr extension in the science file. - + Notes ----- For the case of ACS/WFC every 68th column is wider than the rest. - To compensate for this a small correction needs to be applied to the - detector coordinates. We call this a detector to image transformation. - The so obtained image coordinates are the input to all other distortion - corrections. The correction is originally stored in an external - reference file pointed to by 'D2IMFILE' keyword in the primary header. - This class attaches the correction array as an extension to the science - file with extname = `d2imarr`. - + To compensate for this a small correction needs to be applied to the + detector coordinates. We call this a detector to image transformation. + The so obtained image coordinates are the input to all other distortion + corrections. The correction is originally stored in an external + reference file pointed to by 'D2IMFILE' keyword in the primary header. + This class attaches the correction array as an extension to the science + file with extname = `d2imarr`. + Other keywords used in this correction are: - `AXISCORR`: integer (1 or 2) - axis to which the detector to image + `AXISCORR`: integer (1 or 2) - axis to which the detector to image correction is applied - + `D2IMEXT`: string = name of reference file which was used to create the lookup table extension - + `D2IMERR`: float, optional - maximum value of the correction - + """ def updateWCS(cls, fobj): """ Parameters ---------- fobj: pyfits object - Science file, for which a detector to image correction + Science file, for which a detector to image correction is available - + Notes ----- - Uses the file pointed to in the primary header keyword 'D2IMFILE' - to create an extension with a detector to image correction. + Uses the file pointed to in the primary header keyword 'D2IMFILE' + to create an extension with a detector to image correction. """ logger.info("\n\tStarting Det2IM Correction: %s" % time.asctime()) try: @@ -54,7 +54,7 @@ class DET2IMCorr(object): except AssertionError: logger.exception('\n\tInput must be a pyfits.HDUList object') raise - + d2imfile = fileutil.osfn(fobj[0].header['D2IMFILE']) axiscorr = cls.getAxisCorr(d2imfile) d2imerr = pyfits.getdata(d2imfile, ext=1).max() @@ -64,15 +64,15 @@ class DET2IMCorr(object): new_kw = {'D2IMEXT': d2imfile, 'AXISCORR': axiscorr, 'D2IMERR': d2imerr} cls.applyDet2ImCorr(fobj,axiscorr) cls.updatehdr(fobj, new_kw) - - updateWCS = classmethod(updateWCS) - + + updateWCS = classmethod(updateWCS) + def getAxisCorr(cls, refname): try: direction = pyfits.getval(refname, 'EXTNAME', ext=1) if direction == 'DX': return 1 elif direction == 'DY': return 2 - else: + else: logger.warning('\n\tDET2IM correction expects the reference file to have \ an EXTNAME keyword of value "DX" or "DY", EXTNAMe %s detected' % direction) return None @@ -82,7 +82,7 @@ class DET2IMCorr(object): direction = None return direction getAxisCorr = classmethod(getAxisCorr) - + def applyDet2ImCorr(cls,fobj, axiscorr): binned = utils.getBinning(fobj) hdu = cls.createDgeoHDU(fobj, axiscorr, binned) @@ -92,7 +92,7 @@ class DET2IMCorr(object): else: fobj.append(hdu) applyDet2ImCorr = classmethod(applyDet2ImCorr) - + def getD2imIndex(cls,fobj): index = None for e in range(len(fobj)): @@ -104,43 +104,43 @@ class DET2IMCorr(object): index = e return index getD2imIndex = classmethod(getD2imIndex) - + def createDgeoHDU(cls, fobj, axiscorr, binned=1): d2imfile = fileutil.osfn(fobj[0].header['D2IMFILE']) d2im_data = pyfits.getdata(d2imfile, ext=1) sci_hdr = fobj['sci',1].header d2im_hdr = cls.createDet2ImHdr(fobj, binned) hdu = pyfits.ImageHDU(header=d2im_hdr, data=d2im_data) - + return hdu - + createDgeoHDU = classmethod(createDgeoHDU) - - def createDet2ImHdr(cls, fobj, binned=1): + + def createDet2ImHdr(cls, fobj, binned=1): """ - Creates a header for the D2IMARR extension based on the + Creates a header for the D2IMARR extension based on the reference file recorded in D2IMFILE keyword in the primary header. fobj - the science file - + """ d2imfile = fileutil.osfn(fobj[0].header['D2IMFILE']) axiscorr = cls.getAxisCorr(d2imfile) sci_hdr = fobj[1].header data_shape = pyfits.getdata(d2imfile, ext=1).shape naxis = pyfits.getval(d2imfile, 'NAXIS', ext=1 ) - - kw = { 'NAXIS': 'Size of the axis', - 'CRPIX': 'Coordinate system reference pixel', + + kw = { 'NAXIS': 'Size of the axis', + 'CRPIX': 'Coordinate system reference pixel', 'CRVAL': 'Coordinate system value at reference pixel', 'CDELT': 'Coordinate increment along axis'} - + 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] = data_shape[i-1] @@ -148,8 +148,8 @@ class DET2IMCorr(object): kw_val1['CDELT'+si] = 1./binned kw_val1['CRVAL'+si] = (sci_hdr.get('NAXIS'+si, 1)/2. + \ sci_hdr.get('LTV'+si, 0.)) / binned - - + + kw_comm0 = {'XTENSION': 'Image extension', 'BITPIX': 'IEEE floating point', 'NAXIS': 'Number of axes', @@ -158,7 +158,7 @@ class DET2IMCorr(object): 'PCOUNT': 'Special data area of size 0', 'GCOUNT': 'One data group', 'AXISCORR': 'Direction in which the det2im correction is applied'} - + kw_val0 = { 'XTENSION': 'IMAGE', 'BITPIX': -32, 'NAXIS': naxis, @@ -168,8 +168,8 @@ class DET2IMCorr(object): 'GCOUNT': 1, 'AXISCORR': axiscorr } - - + + cdl = pyfits.CardList() for key in kw_comm0.keys(): cdl.append(pyfits.Card(key=key, value=kw_val0[key], comment=kw_comm0[key])) @@ -189,15 +189,15 @@ class DET2IMCorr(object): if start_indx >= 0: for card in d2im_phdr[start_indx:end_indx]: cdl.append(card) - + 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 + Update extension headers to keep record of the files used for the detector to image correction. """ for ext in fobj: @@ -211,4 +211,4 @@ class DET2IMCorr(object): else: continue updatehdr = classmethod(updatehdr) - + |