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Basic Information on imgen
Purpose: All-purpose image manipulator/creator
Categories: utility, map manipulation
IMGEN is a MIRIAD task that modifies an image, or creates a new
image. See also maths to create images based on expressions
involving X, Y and Z.
The input image, which is to be modified. The default is a map
with one plane which consists entirely of zeros.
The name of the output image. The output image has the same
characteristics as the input image, if present. If no input
image is given, the `imsize', `cell' and `radec' keywords give
the characteristics of the output. No default.
Factor to multiply the input image by. This is meaningless if no
input image is given. The default is 1.
This determines the type of objects added to the input image.
Several objects can be given (of the same type or different).
Minimum match is supported. Possible objects are:
level An offset (DC) level.
noise Noise (gaussian distribution).
point A point source.
gaussian An elliptical or circular gaussian.
gauss3 3D elliptical or circular gaussian (for cubes).
disk An elliptical or circular disk.
j1x J1(x)/x function
jet Jet model with power law brightness.
shell 2D projection of an optically-thin spherical shell
comet 2D projection of a parent molecule in comet.
cluster standard isothermal 2D projection for cluster gas.
Parameters which give the characteristics of the object. The
parameters are given as a sequence of values, with one to six
values needed per object (depending on the object type). When
there are multiple objects, the parameter value for the second
object follow those for the first object, etc. The values are
Object Type SPAR values
cluster amp,x,y,core radius
Here offset is the offset level, "rms" is the rms value of the
noise, "amp" is the normally peak value of the object (but see
options=totflux below), "x" and "y" are the offset positions (in
arcsec) of the object relative to the reference pixel, "z" is
the absolute pixel position on the third axis, "bmaj" and "bmin"
are the major and minor axes FWHM (in arcsec), "pa" is the
position angle of the major axis (in deg), and "bz" is the FWHM
(in pixels) in the 3rd dimension. The position angle is
measured from north towards east.
Comet scalelength, and cluster core radius are in arcsec units.
Jet model has brightness with power law index bmaj and bmin
along major and minor axes.
The default is an object of unit amplitude, at the reference
pixel, with a FWHM of 5 arcsec in x and y and 5 pixels in z.
If not input image is given, then this determines the size, in
pixels, of the output image. Either one or two numbers can be
given. If only one number is given, then the output is square.
For testing purposes a third number can be given to create a
cube, no good coordinate headers however are written for such
cubes. Default is 256 pixels square.
The increment between pixels, in arcsec. Only used if there is
no input map. Default is 1 arcsec.
If no input image is given, this gives the RA and DEC of the
image, in hours and degrees, respectively. They can be given in
hh:mm:ss,dd:mm:ss, or as decimal hours and degrees. The default
is RA=0, DEC=30.
Extra processing options. Several can be given, separated by
commas. Minimum match is used. Possible values are:
totflux Interpret the "amp" values in the spar keyword as
total integrated flux densities (Normally the "amp"
parameters are interpretted as peak values).
Integer used to initialise the random number generator. The
same value of SEED produces the same noise, different values
produce different noise.
Revision: 1.6, 2011/10/24 06:35:38 UTC
Generated by email@example.com on 24 Oct 2011