The kmos_flat recipe =============================================================== .. data:: kmos_flat Synopsis -------- Create master flatfield frame and badpixel map Description ----------- This recipe creates the master flat field and calibration frames needed for spatial calibration for all three detectors. It must be called after the kmo_dark-recipe, which generates a bad pixel mask (badpixel_dark.fits). The bad pixel mask will be updated in this recipe. As input at least 3 dark frames, 3 frames with the flat lamp on are recommended. Additionally a badpixel mask from kmo_dark is required. The badpixel mask contains 0 for bad pixels and 1 for good ones. The structure of the resulting xcal and ycal frames is quite complex since the arrangement of the IFUs isn't just linear on the detector. Basically the integer part of the calibration data shows the offset of each pixels centre in mas (Milli arcsec) from the field centre. The viewing of an IFU is 2800 mas (14pix*0.2arcsec/pix). So the values in these two frames will vary between +/-1500 (One would expect 1400, but since the slitlets aren't expected to be exactly vertical, the values can even go up to around 1500). Additionally in the calibration data in y-direction the decimal part of the data designates the IFU to which the slitlet corresponds to (for each detector from 1 to 8). Because of the irregular arrangement of the IFUs not all x-direction calibration data is found in xcal and similarly not all y-direction calibration data is located in ycal. For certain IFUs they are switched and/or flipped in x- or y-direction: For IFUs 1,2,3,4,13,14,15,16: x- and y- data is switched For IFUs 17,18,19,20: y-data is flipped For IFUs 21,22,23,24: x-data is flipped For IFUs 5,6,7,8,9,10,11,12: x- and y- data is switched and x- and y- data is flipped Furthermore frames can be provided for several rotator angles. In this case the resulting calibration frames for each detector are repeatedly saved as extension for every angle. Advanced features: ------------------ To create the badpixel mask the edges of all slitlets are fitted to a polynomial. Since it can happen that some of these fits (3 detectors 8 IFUs * 14slitlets * 2 edges (left and right edge of slitlet)= 672 edges) fail, the fit parameters are themselves fitted again to detect any outliers. By default, the parameters of all left and all right edges are grouped individually and then fitted using chebyshev polynomials. The advantage of a chebyshev polynomial is, that it consists in fact of a series of orthogonal polynomials. This implies that the parameters of the polynomials are independent. This fact predestines the use of chebyshev polynomials for our case. So each individual parameter can be examined independently. The reason why the left and right edges are fitted individually is that there is a systematic pattern specific to these groups. The reason for this pattern is probably to be found in the optical path the light is traversing. Input files ^^^^^^^^^^^^ :: DO CATG Type Explanation Required #Frames ------- ----- ----------- -------- ------- FLAT_ON RAW Flatlamp-on exposures Y 1-n (at least 3 frames recommended) FLAT_OFF RAW Flatlamp-off exposures Y 1-n (at least 3 frames recommended) BADPIXEL_DARK B2D Bad pixel mask Y 1 Output files ^^^^^^^^^^^^ :: DO CATG Type Explanation ------- ----- ----------- MASTER_FLAT F2D Normalised flat field (6 extensions: alternating data & noise BADPIXEL_FLAT B2D Updated bad pixel mask (3 Extensions) XCAL F2D Calibration frame 1 (3 Extensions) YCAL F2D Calibration frame 2 (3 Extensions) FLAT_EDGE F2L Frame containing parameters of fitted slitlets of all IFUs of all detectors Constructor ----------- .. method:: cpl.Recipe("kmos_flat") :noindex: Create an object for the recipe kmos_flat. :: import cpl kmos_flat = cpl.Recipe("kmos_flat") Parameters ---------- .. py:attribute:: kmos_flat.param.badpix_thresh The threshold level to mark bad pixels [%]. (int; default: 35) [default=35]. .. py:attribute:: kmos_flat.param.surrounding_pixels The nb of bad surrounding pix to mark a pixel bad (int; default: 5) [default=5]. .. py:attribute:: kmos_flat.param.suppress_extension Suppress arbitrary filename extension (bool; default: False) [default=False]. .. py:attribute:: kmos_flat.param.cmethod Apply "average", "median", "sum", "min_max." or "ksigma". (str; default: 'ksigma') [default="ksigma"]. .. py:attribute:: kmos_flat.param.cpos_rej The positive rejection threshold for kappa-sigma-clipping (sigma). (float; default: 3.0) [default=3.0]. .. py:attribute:: kmos_flat.param.cneg_rej The negative rejection threshold for kappa-sigma-clipping (sigma). (float; default: 3.0) [default=3.0]. .. py:attribute:: kmos_flat.param.citer The number of iterations for kappa-sigma-clipping. (int; default: 3) [default=3]. .. py:attribute:: kmos_flat.param.cmax The number of maximum pixel values to clip with min/max-clipping. (int; default: 1) [default=1]. .. py:attribute:: kmos_flat.param.cmin The number of minimum pixel values to clip with min/max-clipping. (int; default: 1) [default=1]. .. py:attribute:: kmos_flat.param.det Only reduce the specified detector (int; default: 0) [default=0]. .. py:attribute:: kmos_flat.param.angle Only reduce the specified angle (float; default: 370.0) [default=370.0]. The following code snippet shows the default settings for the available parameters. :: import cpl kmos_flat = cpl.Recipe("kmos_flat") kmos_flat.param.badpix_thresh = 35 kmos_flat.param.surrounding_pixels = 5 kmos_flat.param.suppress_extension = False kmos_flat.param.cmethod = "ksigma" kmos_flat.param.cpos_rej = 3.0 kmos_flat.param.cneg_rej = 3.0 kmos_flat.param.citer = 3 kmos_flat.param.cmax = 1 kmos_flat.param.cmin = 1 kmos_flat.param.det = 0 kmos_flat.param.angle = 370.0 You may also set or overwrite some or all parameters by the recipe parameter `param`, as shown in the following example: :: import cpl kmos_flat = cpl.Recipe("kmos_flat") [...] res = kmos_flat( ..., param = {"badpix_thresh":35, "surrounding_pixels":5}) .. seealso:: `cpl.Recipe `_ for more information about the recipe object. Bug reports ----------- Please report any problems to `Alex Agudo Berbel, Yves Jung `_. Alternatively, you may send a report to the `ESO User Support Department `_. Copyright --------- This file is part of the CRIRES Instrument Pipeline Copyright (C) 2002,2003 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA .. codeauthor:: Alex Agudo Berbel, Yves Jung