Examples

 > IEXC PIX                interactively exclude individual pixels
 
 > IEXC SOURCE LIST=PSLIST RAD=5      exclude pixels up to a radius
                                      of 5 axis units from positions
                                      in given source list
 
 > IEXC CIRC OUTSIDE       exclude pixels outside given circle
 
 
 > IEXC REG CURR           exclude pixels in current region as
                           previously defined by IREGION