Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_realtime_topography”.

  FT_REALTIME_TOPOGRAPHY reads continuous data from a file or from a data stream,
  estimates the power and plots the scalp topography in real time.
  Use as
  with the following configuration options
    cfg.blocksize            = number, size of the blocks/chuncks that are processed (default = 1 second)
    cfg.overlap              = number, amojunt of overlap between chunks (default = 0 seconds)
    cfg.layout               = specification of the layout, see FT_PREPARE_LAYOUT
  The source of the data is configured as
    cfg.dataset       = string
  or alternatively to obtain more low-level control as
    cfg.datafile      = string
    cfg.headerfile    = string
    cfg.eventfile     = string
    cfg.dataformat    = string, default is determined automatic
    cfg.headerformat  = string, default is determined automatic
    cfg.eventformat   = string, default is determined automatic
  To stop this realtime function, you have to press Ctrl-C
  Example use
    cfg           = [];
    cfg.dataset   = 'PW02_ingnie_20061212_01.ds';
    cfg.layout    = 'CTF151.lay';   = 'MEG';
    cfg.blocksize = 0.5;
    cfg.overlap   = 0.25;
    cfg.demean    = 'yes';
    cfg.bpfilter  = [15 25];
    cfg.bpfreq    =	 'yes';