Source code for drizzlepac.wfc3Data

"""
`wfc3Data` module provides classes used to import WFC3 specific instrument data.

:Authors: Megan Sosey, Christopher Hanley

:License: :doc:`LICENSE`

"""
from stsci.tools import fileutil
from nictools import readTDD
from .imageObject import imageObject
import numpy as np

[docs]class WFC3InputImage(imageObject): SEPARATOR = '_' def __init__(self, filename=None, output=None, group=None): super().__init__(filename, output=output, group=group) # define the cosmic ray bits value to use in the dq array self.cr_bits_value = 4096 self._instrument=self._image["PRIMARY"].header["INSTRUME"] self.flatkey = 'PFLTFILE' def _assignSignature(self, chip): """assign a unique signature for the image based on the instrument, detector, chip, and size this will be used to uniquely identify the appropriate static mask for the image this also records the filename for the static mask to the outputNames dictionary """ sci_chip = self._image[self.scienceExt,chip] ny = sci_chip._naxis1 nx = sci_chip._naxis2 detnum = sci_chip.detnum sig = (self.outroot, (nx, ny), int(chip)) #signature is a tuple sci_chip.signature=sig #signature is a tuple
[docs]class WFC3UVISInputImage(WFC3InputImage): def __init__(self,filename=None, output=None, group=None): super().__init__(filename, output=output, group=group) # define the cosmic ray bits value to use in the dq array self.full_shape = (4096,2051) self._detector = self._image["PRIMARY"].header["DETECTOR"] # get cte direction, which depends on which chip but is independent of amp for chip in range(1,self._numchips+1,1): self._assignSignature(chip) #this is used in the static mask if ( chip == 1) : self._image[self.scienceExt,chip].cte_dir = -1 if ( chip == 2) : self._image[self.scienceExt,chip].cte_dir = 1 self._image[self.scienceExt,chip].darkcurrent = self.getdarkcurrent(chip)
[docs] def doUnitConversions(self): # Effective gain to be used in the driz_cr step. Since the # WFC3 images have already been converted to electrons, # the effective gain is 1. for chip in self.returnAllChips(extname=self.scienceExt): chip._effGain=1.
[docs] def setInstrumentParameters(self, instrpars): """ This method overrides the superclass to set default values into the parameter dictionary, in case empty entries are provided. """ pri_header = self._image[0].header if len(instrpars) == 0: instrpars['proc_unit']='native' instrpars['gain']='' instrpars['rdnoise']='' instrpars['exptime']='' instrpars['gnkeyword']='' instrpars['rnkeyword']='' instrpars['expkeyword']='' if self._isNotValid (instrpars['gain'], instrpars['gnkeyword']): instrpars['gnkeyword'] = 'ATODGNA,ATODGNB,ATODGNC,ATODGND' if self._isNotValid (instrpars['rdnoise'], instrpars['rnkeyword']): instrpars['rnkeyword'] = 'READNSEA,READNSEB,READNSEC,READNSED' if self._isNotValid (instrpars['exptime'], instrpars['expkeyword']): instrpars['expkeyword'] = 'EXPTIME' self.proc_unit = instrpars['proc_unit'] for chip in self.returnAllChips(extname=self.scienceExt): chip._gain = self.getInstrParameter(instrpars['gain'], pri_header, instrpars['gnkeyword']) chip._rdnoise = self.getInstrParameter(instrpars['rdnoise'], pri_header, instrpars['rnkeyword']) chip._exptime = self.getInstrParameter(instrpars['exptime'], pri_header, instrpars['expkeyword']) chip._effGain=chip._gain if chip._gain is None or chip._rdnoise is None or chip._exptime is None: print('ERROR: invalid instrument task parameter') raise ValueError # Convert the science data to electrons. self.doUnitConversions()
[docs] def getdarkcurrent(self,chip): """ Return the dark current for the WFC3 UVIS detector. This value will be contained within an instrument specific keyword. Returns ------- darkcurrent: float The dark current value with **units of electrons**. """ darkcurrent = 0. try: darkcurrent = self._image[self.scienceExt, chip].header['MEANDARK'] except: msg = "#############################################\n" msg += "# #\n" msg += "# Error: #\n" msg += "# Cannot find the value for 'MEANDARK' #\n" msg += "# in the image header. WFC3 input images #\n" msg += "# are expected to have this header #\n" msg += "# keyword. #\n" msg += "# #\n" msg += "# Error occured in WFC3UVISInputImage class #\n" msg += "# #\n" msg += "#############################################\n" raise ValueError(msg) return darkcurrent
[docs]class WFC3IRInputImage(WFC3InputImage): def __init__(self, filename=None, output=None, group=None): super().__init__(filename, output=output, group=group) self.timeExt = 'TIME' # define the cosmic ray bits value to use in the dq array self.full_shape = (1024, 1024) self._detector=self._image["PRIMARY"].header["DETECTOR"] self.native_units = 'ELECTRONS/S' # Effective gain to be used in the driz_cr step. Since the # WFC3 images have already been converted to electrons the # effective gain is 1. self._effGain = 1. # no cte correction for WFC3/IR so set cte_dir=0. self.cte_dir = 0 self._image[self.scienceExt,1].cte_dir = 0 self._image[self.scienceExt,1].darkcurrent = self.getdarkcurrent()
[docs] def doUnitConversions(self): """WF3 IR data come out in electrons, and I imagine the photometry keywords will be calculated as such, so no image manipulation needs be done between native and electrons """ # Image information _handle = fileutil.openImage(self._filename, mode='readonly', memmap=False) for chip in self.returnAllChips(extname=self.scienceExt): conversionFactor = 1.0 if '/S' in chip._bunit: conversionFactor = chip._exptime else: print("Input %s[%s,%d] already in units of ELECTRONS" %(self._filename,self.scienceExt,chip._chip)) chip._effGain = 1.0# chip._gain #1. chip._conversionFactor = conversionFactor #1. _handle.close() self._effGain= 1.0 #conversionFactor #1.0
[docs] def setInstrumentParameters(self, instrpars): """ This method overrides the superclass to set default values into the parameter dictionary, in case empty entries are provided. """ pri_header = self._image[0].header if len(instrpars) == 0: instrpars['proc_unit']='native' instrpars['gain']='' instrpars['rdnoise']='' instrpars['exptime']='' instrpars['gnkeyword']='' instrpars['rnkeyword']='' instrpars['expkeyword']='' if self._isNotValid (instrpars['gain'], instrpars['gnkeyword']): instrpars['gnkeyword'] = 'ATODGNA,ATODGNB,ATODGNC,ATODGND' if self._isNotValid (instrpars['rdnoise'], instrpars['rnkeyword']): instrpars['rnkeyword'] = 'READNSEA,READNSEB,READNSEC,READNSED' if self._isNotValid (instrpars['exptime'], instrpars['expkeyword']): instrpars['expkeyword'] = 'EXPTIME' self.proc_unit = instrpars['proc_unit'] for chip in self.returnAllChips(extname=self.scienceExt): chip._gain = self.getInstrParameter(instrpars['gain'], pri_header, instrpars['gnkeyword']) chip._rdnoise = self.getInstrParameter(instrpars['rdnoise'], pri_header, instrpars['rnkeyword']) chip._exptime = self.getInstrParameter(instrpars['exptime'], pri_header, instrpars['expkeyword']) chip._effGain= 1 if chip._gain is None or chip._rdnoise is None or chip._exptime is None: print('ERROR: invalid instrument task parameter') raise ValueError self._assignSignature(chip.extnum) #this is used in the static mask #Convert from ELECTRONS/S to ELECTRONS self.doUnitConversions()
[docs] def getexptimeimg(self,chip): """ Return an array representing the exposure time per pixel for the detector. Returns ------- dark: array Exposure time array in the same shape as the input image """ return self._image[self.timeExt,chip].data
[docs] def getdarkimg(self,chip): """ Return an array representing the dark image for the detector. Returns ------- dark: array Dark image array in the same shape as the input image with **units of cps** """ sci_chip = self._image[self.scienceExt,chip] # First attempt to get the dark image specified by the "DARKFILE" # keyword in the primary keyword of the science data. try: filename = self.header["DARKFILE"] handle = fileutil.openImage(filename, mode='readonly', memmap=False) hdu = fileutil.getExtn(handle,extn="sci,1") darkobj = hdu.data[sci_chip.ltv2:sci_chip.size2,sci_chip.ltv1:sci_chip.size1] # If the darkfile cannot be located, create the dark image from # what we know about the detector dark current and assume a # constant dark current for the whole image. except: darkobj = (np.ones(sci_chip.image_shape, dtype=sci_chip.image_dtype) * self.getdarkcurrent()) return darkobj
[docs] def getskyimg(self,chip): """ Notes ===== Return an array representing the sky image for the detector. The value of the sky is what would actually be subtracted from the exposure by the skysub step. :units: electrons """ sci_chip = self._image[self.scienceExt,chip] skyimg = np.ones(sci_chip.image_shape,dtype=sci_chip.image_dtype)*sci_chip.subtractedSky if sci_chip._conversionFactor != 1.0: # If units are not already ELECTRONS skyimg *= self.getexptimeimg(chip) return skyimg
[docs] def getdarkcurrent(self): """ Return the dark current for the WFC3/IR detector. This value will be contained within an instrument specific keyword. Returns ------- darkcurrent: float The dark current value in **units of electrons**. """ darkcurrent = 0 try: darkcurrent = self._image[self.scienceExt,1].header['MEANDARK'] except: str = "#############################################\n" str += "# #\n" str += "# Error: #\n" str += "# Cannot find the value for 'MEANDARK' #\n" str += "# in the image header. WFC3 input images #\n" str += "# are expected to have this header #\n" str += "# keyword. #\n" str += "# #\n" str += "# Error occured in WFC3IRInputImage class #\n" str += "# #\n" str += "#############################################\n" raise ValueError(str) return darkcurrent