The uves_cal_mflat recipe
===============================================================

.. data:: uves_cal_mflat

Synopsis
--------

Creates the master flat field frame

Description
-----------

This recipe creates a master flat frame by 1) subtracting the master bias
frame from each flat field frame, 2) dividing each flat field frame by the
 exposure time for that frame, 3) taking the median of all bias subtracted,
 normalized raw
 flat frames, 4) optionally subtracting the master dark 
frame, and 5) subtracting
 the background to get the bias subtracted, 
optionally dark subtracted, normalized, background subtracted master 
flat-field frame. Symbolically,
 masterflat = median( (flat_i - masterbias)/exptime_i ) - masterdark/exptime
            - background.


The input flat field frames must have same tag which must match
(I|D|S|T|SCREEN|)FLAT_(BLUE|RED), for example TFLAT_BLUE or FLAT_RED. Also, a
master bias (MASTER_BIAS_xxxx) and ordertable (ORDER_TABLE_xxxx) must be
provided for each chip (xxxx = BLUE, REDL, REDU). A master dark frame
(MASTER_(P)DARK_xxxx) may optionally be provided. On blue input the recipe
computes one master flat field frame; on red input the recipe produces a
master flat field frame for each chip (MASTER_FLAT_xxxx, MASTER_IFLAT_xxxx,
MASTER_DFLAT_xxxx, MASTER_TFLAT_xxxx or MASTER_SCREEN_FLAT_xxxx).


Constructor
-----------

.. method:: cpl.Recipe("uves_cal_mflat")
   :noindex:

   Create an object for the recipe uves_cal_mflat.

::

   import cpl
   uves_cal_mflat = cpl.Recipe("uves_cal_mflat")

Parameters
----------

.. py:attribute:: uves_cal_mflat.param.backsub.mmethod

    Background measuring method. If equal to 'median' the background is  sampled using the median of a subwindow. If 'minimum', the subwindow  minimum value is used. If 'no', no background subtraction is done.  (str; default: 'median') [default="median"].
.. py:attribute:: uves_cal_mflat.param.backsub.npoints

    This is the number of columns in interorder space used to sample the  background. (int; default: 82) [default=82].
.. py:attribute:: uves_cal_mflat.param.backsub.radiusy

    The height (in pixels) of the background sampling window is (2*radiusy  + 1). This parameter is not corrected for binning. (int; default: 2) [default=2].
.. py:attribute:: uves_cal_mflat.param.backsub.sdegree

    Degree of interpolating splines. Currently only degree = 1 is  supported (int; default: 1) [default=1].
.. py:attribute:: uves_cal_mflat.param.backsub.smoothx

    If spline interpolation is used to measure the background, the  x-radius of the post-smoothing window is (smoothx * image_width).  Here, 'image_width' is the image width after binning. If negative, the  default values are used: (25.0/4096) for blue flat-field frames,  (50.0/4096) for red flat-field frames, (300.0/4096) for blue science  frames and (300.0/4096) for red science frames. (float; default: -1.0) [default=-1.0].
.. py:attribute:: uves_cal_mflat.param.backsub.smoothy

    If spline interpolation is used to measure the background, the  y-radius of the post-smoothing window is (smoothy * image_height).  Here, 'image_height' is the image height after binning. If negative,  the default values are used: (100.0/2048) for blue flat-field frames,  (300.0/2048) for red flat-field frames, (200.0/2048) for blue science  frames and (500.0/2048) for red science frames. (float; default: -1.0) [default=-1.0].
.. py:attribute:: uves_cal_mflat.param.debug

    Whether or not to save intermediate results to local directory (bool;  default: False) [default=False].
.. py:attribute:: uves_cal_mflat.param.norm_method

    Method used to build master frame  (str; default: 'explevel') [default="explevel"].
.. py:attribute:: uves_cal_mflat.param.plotter

    Any plots produced by the recipe are redirected to the command  specified by this parameter. The plotting command must contain the  substring 'gnuplot' and must be able to parse gnuplot syntax on its  standard input. Valid examples of such a command may include 'gnuplot  -persist' and 'cat > mygnuplot$$.gp'. A finer control of the plotting  options can be obtained by writing an executable script, e.g.  my_gnuplot.pl, that executes gnuplot after setting the desired gnuplot  options (e.g. set terminal pslatex color). To turn off plotting, set  this parameter to 'no' (str; default: 'no') [default="no"].
.. py:attribute:: uves_cal_mflat.param.process_chip

    For RED arm data process the redl, redu, or both chip(s) (str;  default: 'both') [default="both"].


The following code snippet shows the default settings for the available 
parameters.

::

   import cpl
   uves_cal_mflat = cpl.Recipe("uves_cal_mflat")

   uves_cal_mflat.param.backsub.mmethod = "median"
   uves_cal_mflat.param.backsub.npoints = 82
   uves_cal_mflat.param.backsub.radiusy = 2
   uves_cal_mflat.param.backsub.sdegree = 1
   uves_cal_mflat.param.backsub.smoothx = -1.0
   uves_cal_mflat.param.backsub.smoothy = -1.0
   uves_cal_mflat.param.debug = False
   uves_cal_mflat.param.norm_method = "explevel"
   uves_cal_mflat.param.plotter = "no"
   uves_cal_mflat.param.process_chip = "both"


You may also set or overwrite some or all parameters by the recipe 
parameter `param`, as shown in the following example:

::

   import cpl
   uves_cal_mflat = cpl.Recipe("uves_cal_mflat")
   [...]
   res = uves_cal_mflat( ..., param = {"backsub.mmethod":"median", "backsub.npoints":82})


.. seealso:: `cpl.Recipe <https://packages.python.org/python-cpl/recipe.html>`_
   for more information about the recipe object.

Bug reports
-----------

Please report any problems to `Jonas M. Larsen <cpl@eso.org>`_. Alternatively, you may 
send a report to the `ESO User Support Department <usd-help@eso.org>`_.

Copyright
---------

This file is part of the FLAMES/UVES Pipeline
Copyright (C) 2004, 2005, 2006, 2007 European Southern Observatory

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, 
MA  02111-1307  USA

.. codeauthor:: Jonas M. Larsen <cpl@eso.org>
