read_eeg.m

绝对经典,老外制作的功能强大的matlab实现PLS_TOOBOX

%READ_EEG  will  Read in EEG data file. By default, it will read ASCII 
%  file that contains no header or 1 header line. If EEG_format argument
%  is provided, or if it fails to read ASCII file, it can also read
%  binary data file from different vendors with their corresponding
%  file formats.
%
%  Usage: [data EEG_format] = read_eeg(filename, [EEG_format]);
%
%  data - data matrix with a size of numbers of channel by numbers of
%	time point, or vice versa.
%
%  filename - EEG data file name.
%
%  EEG_format (option) - structure containing a 'vendor' name, and a
%	'machineformat'. If not provided, ASCII file will be assumed.
%
%  - Jimmy Shen ([e-mail])
%
function [data, EEG_format] = read_eeg(filename, varargin)

   if ~exist('filename','var'),
      error('Usage: [data EEG_format] = read_eeg(filename, [EEG_format]);');
   end

   if ~exist(filename,'file')
      error([filename, ': Can''t open file']);
   end

   if nargin > 1
      EEG_format = varargin{1};
   else
      EEG_format = [];
   end

   if ~isempty(EEG_format) & isfield(EEG_format, 'vendor') & ...
	isfield(EEG_format, 'machineformat')

      switch upper(EEG_format.vendor)
         case 'ANT'		% Advanced Neuro Technology

            ant = load_ant(filename, EEG_format.machineformat);
            data = ant.means;

         case 'EGI'		% Electrical Geodesics Inc

            egi = load_egi(filename, EEG_format.machineformat);
            data = egi.data;

         otherwise		% NEUROSCAN and Compumedics

            ns = load_neuroscan(filename, 'avg', EEG_format.machineformat);
            data = ns.data;
      end;

      return;
   end

   try
      data = load(filename);	% fast read for no header EEG file
      return;
   catch
      fid = fopen(filename);	% open file

      if fid == -1		% error to open the file
         error([filename, ': Can''t open file']);
      end

      hdr = fgetl(fid);		% ignore 1st line that is EEG header
      hdr = hdr(1:4);

      if strcmpi(hdr,'npts') | strcmpi(hdr,'[ave')

         %  If it is BESA file, call strip_besa_hdr routine
         %
         fclose(fid);
         data = strip_besa_hdr(filename);

      else

         %  Otherwise, simply try the rest of lines by ignoring
         %  the 1st line, and convert data to double
         %
         i = 1;
         while ~feof(fid)
            tmp = fgetl(fid);
            if ~ischar(tmp)
               if isnumeric(tmp) & tmp == -1
               else
                  data = [];
               end
               break;
            end

            tmp = str2num(tmp);
            if isempty(tmp)
               data = [];
               break;
            end

            if exist('data','var') & length(tmp) ~= size(data,2)
               data = [];
               break;
            end

            data(i,:) = tmp;
            i = i + 1;
         end

         fclose(fid);

      end

   end

   %  If fail to read ASCII file, try to read binary file from
   %  different vendors with their corresponding file formats.
   %
   if isempty(data)
      EEG_format = read_eeg_format;

      if isempty(EEG_format)
         data = [];
         return;
      end

      data = read_eeg(filename, EEG_format);
   end

   return;					% read_eeg