Documentation on imgen
Task: imgen
Purpose: All-purpose image manipulator/creator
Categories: utility, map manipulation
IMGEN is a MIRIAD task which modifies an image, or creates a new
image.
Key: in
The input image, which is to be modified. The default is a map
with one plane which consists entirely of zeros.
Key: out
The name of the output image. No default. 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.
Key: factor
Factor to multiply the input image by. This is meaningless if no
input image is given. The default is 1.
Key: object
This determines the type of objects added to the input image.
Several objects can be given (the objects can be the same type, or
different), and 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.
disk An elliptical or circular disk.
j1x A J1(x)/x function
shell 2D projection of an optically-thin spherical shell
Key: spar
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
as follows:
Object Type SPAR values
----------- -----------
level offset
noise rms
point amp,x,y
gaussian amp,x,y,bmaj,bmin,pa
disk amp,x,y,bmaj,bmin,pa
j1x amp,x,y,bmaj,bmin,pa
shell amp,x,y,bmaj
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, "bmaj" and
"bmin" are the major and minor axes FWHM (in arcsec), and "pa" is
the position angle of an elliptical component (in degrees). The
position angle is measured from north towards east.
The default is an object of unit amplitude, at the reference pixel,
with a FWHM of 5 arcsec.
Key: imsize
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.
The default is 256 pixels square.
Key: cell
The increment between pixels, in arcseconds. This is only used if
there is no input map. The default is 1 arcsec.
Key: radec
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=45.
Key: options
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).
Generated by rsault@atnf.csiro.au on 11 Jul 1996