NOISE

        SHOW NOISE [VarName [Rms]]

    Compute and display the noise statistic of the specified SIC variable, using
    a  Gaussian fit to the histogram of pixel intensities for each channel. Var-
    Name  must be the name of a 2-D or 3-D SIC image variable.

    If no VarName is specified, the last displayed image (by SHOW  or  VIEW)  is
    used.  If  none  was ever displayed, SHOW selects among SKY, CLEAN and DIRTY
    images in this priority order.

    If specified, Rms indicates the expected rms noise of  the  data,  which  is
    otherwised  taken  from  the data itself. It is used to automatically scaled
    the display to provide a good sampling of the noise distribution.

    See SHOW INTENSITY for a Log scale equivalent.