- NAME
SKYADJ_CUBE
- PURPOSE
Sky adjust the planes of a datacube.
- EXPLANATION
When removing cosmic rays from a set of images, it is desirable that
all images have the same sky level. This procedure (called by
CR_REJECT) removes the sky from each image in a data cube.
- CALLING SEQUENCE
SKYADJ_CUBE,Datacube,Skyvals,Totsky
- MODIFIED ARGUMENT
Datacube: 3-D array with one image of same field in each plane.
Returned with sky in each plane adjusted to zero.
- OUTPUT ARGUMENTS
Skyvals: Array of sky values used on each plane of datacube.
For a scalar sky, this parameter is a vector
containing the sky value for each image plane. For a
vector sky, this parameter is a 2-D array where each
line corresponds to one image plane.
- INPUT KEYWORD PARAMETERS
REGION - [X0,X1,Y0,Y1] to restrict area used for computation
of sky. Default is 0.1*Xdim, 0.9*Xdim, 0.1*Ydim,
0.9*Ydim. If INPUT_MASK is specified, the two
specs are combined, i.e., the intersection of the
areas is used.
VERBOSE - Flag. If set, print information on skyvals.
NOEDIT - Flag. If set, return sky values without changing
datacube.
XMEDSKY - Flag. If set, return vector sky as a function of X.
SELECT - Array of subscripts of planes of the cube to process.
(Default=all)
EXTRAPR - Applies only in XMEDSKY mode.
Subregion to use for polynomial extrapolation of sky
vector into portions excluded by REGION parameter.
(Default=first and last 10% of pixels; set to zero
to defeat extrapolation)
EDEGREE - Applies only in XMEDSKY mode.
Degree of polynomial for extrapolation (Default=1)
INPUT_MASK - Cube of flags corresponding to data cube. If used,
the sky computation is restricted to the smallest
contiguous rectangle containing all the pixels flagged
valid (with 1 rather than 0).
- PROCEDURE
Uses astronomy library "sky" routine for scalar sky and
column-by-column median for vector sky.
- MODIFICATION HISTORY
10 Jul. 1997 - Written. R. S. Hill, Hughes STX
20 Oct. 1997 - 1-D sky option. RSH
7 Aug. 1998 - SELECT keyword. RSH
6 Oct. 1998 - Extrapolation. RSH
7 Oct. 1998 - INPUT_MASK added. RSH
21 Oct. 1998 - Fallback to 3-sigma clipped mean if mode fails. RSH
22 Mar. 2000 - Combine mask with region rather having mask
override region. Improve comments. RSH
16 June 2000 - On_error and message used. Square brackets for array
subscripts. EXTRAP included in this file.
WBL & RSH, 16 June 2000
- NAME
EXTRAP
- PURPOSE
This procedure fills in the ends of a one-dimensional array from
interior portions using polynomial extrapolation.
- CATEGORY
Image processing
- CALLING SEQUENCE
EXTRAP, Deg, X, Y, Y2
- INPUT POSITIONAL PARAMETERS
Deg: Degree of polynomial
X: Independent variable
Y: Dependent variable
- KEYWORD PARAMETERS
LIMS: 3-element array giving range of X to be used to fit
polynomial and starting point where extrapolation is
to be substituted; if not given, you click on a plot;
order of elements is [xmin, xmax, xstart]; if LIMS is
specified, then program is silent
- OUTPUT POSITIONAL PARAMETERS
Y2: Dependent variable with extrapolated portion filled in
- SIDE EFFECTS
May pop a window for selecting range.
- MODIFICATION HISTORY
Written by RSH, RITSS, 14 Aug 98
Spiffed up for library. RSH, 6 Oct 98