Basic Information on velimage

Task: velimage
Purpose: Make (x,y,z) image from an (x,y) image and model z-values.
Categories: image analysis

        VELIMAGE is a MIRIAD task to make an (x,y,z) image from an (x,y)
        image and a model for the z-values and dispersion.  The
        z-values, for example the mean velocity, are input as an (x,y)
        image, whilst the dispersion can be input as either an (x,y)
        image or a fixed value.  The output image is formed as
 
           out(x,y,z) = in1(x,y) * exp(-(z-in2(x,y))**2/(2*sigma**2)))
 
        VELIMAGE can be used to compare models with the data.  For
        example one can generate a model image corresponding to a
        rotating galaxy, convolve it with the actual beam and subtract
        the model from the data to determine if there is residual
        emission which deviates from the model rotation curve.

Key: in
        The input image names, separated by commas.  The first image is
        the (x,y) intensity distribution integrated over the z-axis,
        e.g. velocity-integrated image.  The second image is an (x,y)
        model for the z-values, e.g. a mean velocity image.  No default
        for either.
        A 3rd input image gives the z-dispersion at each point, e.g. a
        velocity dispersion image.  If the 3rd image is not specified
        then fixed dispersion, sigma must be specified.

Key: region
        Region of image to be used.  See documentation on region for
        details.  All pixels within the bounding box are used; pixel
        masking is not used.  Default is the entire image.

Key: sigma
        Fixed value for z-dispersion if not specified by 3rd input
        image.

Key: nchan
        Number of channels for z-axis of output image.  Default=1.

Key: start
        Starting value for z-axis of output image.  No default.

Key: step
        Interval for z-axis of output image.  No default.

Key: out
        The output (x,y,z) image.  No default.

Key: options
        Options.  Minimum match is active.
          relax  ignore axis descriptor mismatches
                 (e.g. pixel increments etc).  Use with care.
 
Revision: 1.7, 2017/12/11 22:26:28 UTC