Input: meg_dir % $MEG_DIR ex. /data1/toyama2/
sysid % System ID ex. 1000987
Output:
meg_info : structure with following field
.nch, % number of active gardiometers
.nch0 % number of gardiometers
.nsamp, % sampling number of measurement
.nprsamp, % sampling number for pre-trigger
.sampf, % sampling frequency
.nrept, % repeat number
.active_ch % Active channel index
.ch_name % Active channel name
.ch_name0 % All channel name
.ad_factor % AD multiplicative factor to convert MEG data to [T]
pick1(ch,:) % position and direction of detection coils
on DICOM cord. [m],[normal unit vector]
pick2(ch,:) % position and direction of compensation coils
on DICOM cord. [m],[normal unit vector]
Copyright (C) 2011, ATR All Rights Reserved.
License : New BSD License(see VBMEG_LICENSE.txt)0001 function [meg_info, pick1, pick2 ] = read_sbi_meg_header(meg_dir,sysid) 0002 % Input: meg_dir % $MEG_DIR ex. /data1/toyama2/ 0003 % sysid % System ID ex. 1000987 0004 % Output: 0005 % meg_info : structure with following field 0006 % .nch, % number of active gardiometers 0007 % .nch0 % number of gardiometers 0008 % .nsamp, % sampling number of measurement 0009 % .nprsamp, % sampling number for pre-trigger 0010 % .sampf, % sampling frequency 0011 % .nrept, % repeat number 0012 % .active_ch % Active channel index 0013 % .ch_name % Active channel name 0014 % .ch_name0 % All channel name 0015 % .ad_factor % AD multiplicative factor to convert MEG data to [T] 0016 % 0017 % pick1(ch,:) % position and direction of detection coils 0018 % on DICOM cord. [m],[normal unit vector] 0019 % pick2(ch,:) % position and direction of compensation coils 0020 % on DICOM cord. [m],[normal unit vector] 0021 % 0022 % Copyright (C) 2011, ATR All Rights Reserved. 0023 % License : New BSD License(see VBMEG_LICENSE.txt) 0024 0025 % 2005-12-22 M. Sato 0026 0027 global vbmeg_inst; 0028 define = vbmeg_inst.const; 0029 0030 % MEGディレクトリからheaderディレクトリへの相対path 0031 head_dir = '../head/'; 0032 0033 % 0034 % --- read SBI header 0035 % 0036 fname = sprintf('%s%s%s%s',meg_dir,head_dir,sysid,define.HEADER_EXTENSION); 0037 fid = fopen(fname ,'r','l'); 0038 if fid==-1, disp('XXX Error : Cannot open head file !!\n'); return; end 0039 0040 % file info. 0041 H_file = meg_hread('file',fid); 0042 0043 % MEG data dimension 0044 H_meg = meg_hread('meg',fid, H_file.i_meg_begin); 0045 nch0 = H_meg.i_nch; 0046 nsamp = H_meg.i_nsample; % sampling number of measurement 0047 nprsamp = H_meg.i_nprsample; % sampling number for pre-trigger 0048 sampf = H_meg.i_samp_freq; % sampling frequency 0049 nrept = H_meg.i_nwave; % repeat number 0050 vbit = H_meg.f_ad_weight; % ＡＤ変換器１ｂｉｔの重み[V/digit] 0051 0052 % Sensor variable 0053 kind0 = zeros(nch0,1); 0054 lock0 = zeros(nch0,1); 0055 amp0 = zeros(nch0,1); 0056 sens0 = zeros(nch0,1); 0057 0058 chname0= cell(nch0,1); 0059 0060 pick10 = zeros(nch0,6); 0061 pick20 = zeros(nch0,6); 0062 0063 % Sensor position 0064 for i=1:nch0 0065 H_meg_ch = meg_hread('meg_ch',fid,... 0066 H_file.i_meg_ch_begin + H_file.i_meg_ch_size*(i-1)); 0067 0068 kind0(i) = H_meg_ch.i_pick_type; % ピックアップコイルタイプ 0069 lock0(i) = H_meg_ch.i_meg_lock; % ＭＥＧ計測時のＳＱＵＩＤロック状態 0070 amp0(i) = H_meg_ch.f_amp_gain; % 増幅器増幅度 0071 sens0(i) = H_meg_ch.f_phy_v_coef; % 磁束−電圧変換係数［Ｔ／Ｖ］ 0072 chname0{i} = H_meg_ch.c_ch_name; 0073 0074 % sensor position 0075 pick10(i,1:3) = (H_meg_ch.st_dcp)'; 0076 pick10(i,4:6) = (H_meg_ch.st_dca)'; 0077 pick20(i,1:3) = (H_meg_ch.st_ccp)'; 0078 pick20(i,4:6) = (H_meg_ch.st_cca)'; 0079 end 0080 0081 fclose(fid); 0082 0083 clear H_file H_meg 0084 0085 % 0086 % --- select active coils and data 0087 % 0088 % kind0 ; ピックアップコイルタイプ 0089 % ０：マグネトメータ １：グラジオメータ 0090 % lock0 ; ＭＥＧ計測時のＳＱＵＩＤロック状態 0091 % ０：ロック １：リセット ２:エラー 0092 0093 % Index for active gardiometers 0094 okix=find(kind0==1 & lock0==0); 0095 % number of active gardiometers 0096 nch=length(okix); 0097 0098 % position and direction of detection coils on DEWAR cord. ([m],[rad,]) 0099 pick1=pick10(okix,:); 0100 % position and direction of compensation coils on DEWAR cord. ([m],[rad,]) 0101 pick2=pick20(okix,:); 0102 0103 % AD multiplicative factor to convert MEG data to [T] 0104 % bexp = bexp0 .* (sens0) * vbit ./(amp0); 0105 amp = vbit*sens0(okix)./amp0(okix); 0106 0107 chname = cell(1,nch); 0108 0109 for i=1:nch 0110 chname{i}=chname0{okix(i)}; 0111 end 0112 0113 meg_info = struct( ... 0114 'nch',nch, ... % number of active gardiometers 0115 'nch0',nch0, ... % number of gardiometers 0116 'nsamp',nsamp, ... % sampling number of measurement 0117 'nprsamp',nprsamp, ... % sampling number for pre-trigger 0118 'sampf',sampf, ... % sampling frequency 0119 'nrept',nrept); % repeat number 0120 0121 meg_info.active_ch = okix; % Active channel index 0122 meg_info.ch_name = chname; % Active channel name 0123 meg_info.ch_name0 = chname0; % All channel name 0124 meg_info.ad_factor = amp; % AD factor to convert MEG data to [T]