remove bias from MEG data
[usage]
[data] = vb_megfile_remove_bias(megfile)
[input]
megfile : <required> <<file>> MEG-MAT file
procspec : <optional> <<struct>> specification of removing
: <<fields>>
: .channel_type : channel type
: : [1]) MEG
: : 2 ) EXTRA
: : 3 ) REFFERENCE
: .method : how to remove (defined in vb_define_mode)
: : [0]) REMOVE_BIAS_OFF
: : 1 ) REMOVE_BIAS_PRETRIGGER
: : 2 ) REMOVE_BIAS_LINEAR
[output]
data : processed data
[note]
if specified REMOVE_BIAS_OFF, only returns loaded data
[history]
2007-07-13 (Sako) separated from Yoshioka-san's program
2008-06-06 (Sako) modified using new vb_load_meg_data
Copyright (C) 2011, ATR All Rights Reserved.
License : New BSD License(see VBMEG_LICENSE.txt)0001 function [data] = vb_megfile_remove_bias(megfile, procspec) 0002 % remove bias from MEG data 0003 % [usage] 0004 % [data] = vb_megfile_remove_bias(megfile) 0005 % [input] 0006 % megfile : <required> <<file>> MEG-MAT file 0007 % procspec : <optional> <<struct>> specification of removing 0008 % : <<fields>> 0009 % : .channel_type : channel type 0010 % : : [1]) MEG 0011 % : : 2 ) EXTRA 0012 % : : 3 ) REFFERENCE 0013 % : .method : how to remove (defined in vb_define_mode) 0014 % : : [0]) REMOVE_BIAS_OFF 0015 % : : 1 ) REMOVE_BIAS_PRETRIGGER 0016 % : : 2 ) REMOVE_BIAS_LINEAR 0017 % [output] 0018 % data : processed data 0019 % [note] 0020 % if specified REMOVE_BIAS_OFF, only returns loaded data 0021 % [history] 0022 % 2007-07-13 (Sako) separated from Yoshioka-san's program 0023 % 2008-06-06 (Sako) modified using new vb_load_meg_data 0024 % 0025 % Copyright (C) 2011, ATR All Rights Reserved. 0026 % License : New BSD License(see VBMEG_LICENSE.txt) 0027 0028 % --- CHECK ARGUMENTS --- % 0029 if ~exist('megfile', 'var'), megfile = []; end 0030 if ~exist('procspec', 'var'), procspec = []; end 0031 [megfile, procspec] = inner_check_arguments(megfile, procspec); 0032 0033 % --- MAIN PROCEDURE --------------------------------------------------------- % 0034 % 0035 const_def = vb_define_mode; 0036 func_ = mfilename; 0037 0038 const = vb_define_const; 0039 switch procspec.channel_type 0040 case 1 % MEG 0041 loadspec.ChannelType = const.DATA_TYPE_MAIN; 0042 data = vb_load_meg_data(megfile, loadspec); 0043 case 2 % EXTRA 0044 loadspec.ChannelType = const.DATA_TYPE_EXTRA; 0045 data = vb_load_meg_data(megfile, loadspec); 0046 case 3 % REFFERENCE 0047 loadspec.ChannelType = const.DATA_TYPE_REFERENCE; 0048 data = vb_load_meg_data(megfile, loadspec); 0049 otherwise 0050 error('(%s)unexpected channel_type in procspec : %d', ... 0051 func_, procspec.channel_type); 0052 end 0053 0054 if procspec.method == const_def.REMOVE_BIAS_OFF 0055 % do nothing 0056 return; 0057 end 0058 0059 meginfo = vb_megfile_load_meginfo(megfile); 0060 0061 % every trial - data [Nchannel x Nsample x Ntrial] 0062 for i=1:size(data,3) 0063 switch procspec.method 0064 0065 case const_def.REMOVE_BIAS_PRETRIGGER 0066 pre = vb_meginfo_get_pre_trigger(meginfo); 0067 0068 if ~isempty(pre) && pre > 0, 0069 tmp = mean(data(:, 1:pre ,i )')'; 0070 data(:, :, i) = data(:, :, i) - repmat(tmp, [1 size(data, 2)]); 0071 else 0072 warning('(%s)there is not pretrigger in MEG-MAT file: %s\n', ... 0073 func_, megfile); 0074 % need to confirmation whether it can be returned here or not 0075 return; 0076 end 0077 0078 case const_def.REMOVE_BIAS_LINEAR 0079 % not be implemented yet 0080 end 0081 end 0082 return; 0083 % 0084 % --- END OF MAIN PROCEDURE -------------------------------------------------- % 0085 0086 % --- INNER FUNCTIONS -------------------------------------------------------- % 0087 % 0088 % --- inner_check_arguments() 0089 % 0090 function [megfile, procspec] = inner_check_arguments(megfile, procspec) 0091 func_ = mfilename; 0092 0093 if isempty(megfile) 0094 error('(%s)megfile is a required parameter', func_); 0095 end 0096 0097 if exist(megfile, 'file') ~= 2 0098 error('(%s)cannot find MEG-MAT file : %s', func_, megfile); 0099 end 0100 0101 if isempty(procspec) 0102 procspec.channel_type = 1; % MEG 0103 procspec.method = 0; % OFF 0104 else 0105 if ~isfield(procspec, 'channel_type') 0106 procspec.channel_type = 1; % MEG 0107 end 0108 if ~isfield(procspec, 'method') 0109 procspec.method = 0; % OFF 0110 end 0111 end 0112 0113 return; 0114 % 0115 % --- end of inner_check_arguments() 0116 % 0117 % --- END OF INNER FUNCTIONS ------------------------------------------------- % 0118 0119 %%% END OF FILE %%%