BCIduino脑机社区|EEG bdf reader
通过以下代码可以从一个bdf文件中读取数据（需要将以下代码保存为一个.m文件：eeg_read_bdf.m）。
参考：
https://www.mathworks.com/matlabcentral/fileexchange/13070-eeg-bdf-reader
function[data,numChan,labels,txt,fs,gain,prefiltering,ChanDim] = eeg_read_bdf(filename,SecLoad,reshape)
% this function loads at least "SecLoad" seconds of EEG data from the
% specified bdf-file "filename". If all available data is needed, specify
% 'all' instead of "SecLoad" like this:
% [...] = eeg_read_bdf('test.bdf','all');
% EEg data is read from the first sample.
% "reshape" ('y' or 'n') specifies whether data must be reshaped (ActiveTwo
% by BioSemi 65 electrodes)... according to author's humble understanding.
%
% The outputs are:
% "data" - EEG data of size numChan by SecLoad*fs
% "numChan" - number of EEG channel (including the status channel)
% "labels" - EEG electrode labels
% "txt" - a string containg information about the subject entered wile
% recorging EEG
% "fs" - sampling frequency, Hz
% "gain" - gain factor, times
% "ChanDim" - Physical dimension of the EEG channels (for instance, uV)
% "prefiltering" - information about filters used during EEG recording
%
% Note: for some reason, bdf format specifies separate sets of "fs",
% "gain", "ChanDim", and "prefiltering" for every EEG channel. This
% function returns these values for the first channel (electrode) only!
%
% Copyleft by Gleb Tcheslavski, gleb@vt.edu
if ~exist(filename,'file')
error(['Specified file ' filename ' does not exist in MATLAB path.']);
end
idx = [1 34 5 40 13 50 21 58 27 64 7 42 15 52 23 60 38 48 31 47 32 18 55 10 45 16 53 8 43 33 37 30 26 63 3 36 2 35 25 62 4 39 12 49 20 57 6 41 9 44 14 51 17 54 22 59 19 56 11 46 24 61 28 29 65];
fid = fopen(filename);
fseek(fid,130,'bof');
txt = cellstr(char(fread(fid,54,'10*char'))'); %user text
fseek(fid,236,'bof');
numRec =str2double(deblank(char(fread(fid,7,'1*char')))); %number of data records
fseek(fid,244,'bof');
RecDur = str2double(deblank(char(fread(fid,3,'1*char')))); %duration of a data record, sec
fseek(fid,252,'bof');
numChan = str2double(deblank(char(fread(fid,3,'1*char')))); %number of EEG channels
fseek(fid,256,'bof');
labels = cellstr(deblank(char(fread(fid,7,numChan],'7*char',9)')));
%EEG labels
if reshape == 'y'
labels={
'Fp1','Fp2','F3','F4','C3','C4','P3','P4','O1','O2','F7','F8','T7','T8','P7','P8','Fz','Cz','Pz','Fcz','Cpz','Cp3','Cp4'... 'Fc3' 'Fc4' 'Tp7' 'Tp8' 'Ft7' 'Ft8' 'Fpz' 'Afz' 'Poz' 'Po3' 'Po4' 'Af3' 'Af4' 'Af7' 'Af8' 'Po7' 'Po8' 'F1' 'F2' 'C1' 'C2' 'P1' 'P2'... 'F5' 'F6' 'Fc5' 'Fc6' 'C5' 'C6' 'Cp5' 'Cp6' 'P5' 'P6' 'Cp1' 'Cp2' 'Fc1' 'Fc2' 'P9' 'P10' 'Iz' 'Oz' 'Status'};endfseek(fid,256+numChan*136,'bof');
prefiltering = cellstr(char(fread(fid,25,'10*char'))'); %filters applied - need to check from this pointfseek(fid,256+numChan*96,'bof');
ChanDim = cellstr(deblank(char(fread(fid,5,'5*char'))'));
%Physical dimention of the channels (uV, for instance)
fseek(fid,256+numChan*216,'bof');
numSam = str2double(deblank(char(fread(fid,4,'1*char'))));
%number of samples in each recordfs = numSam/RecDur;
%sampling frequencyfseek(fid,256+numChan*104,'bof');
Pmin = str2double(deblank(char(fread(fid,8,'1*char'))));
%physical minfseek(fid,256+numChan*112,'bof');
Pmax = str2double(deblank(char(fread(fid,8,'1*char'))));
%physical maxfseek(fid,256+numChan*120,'bof');
Dmin = str2double(deblank(char(fread(fid,8,'1*char'))));
%digital minfseek(fid,256+numChan*128,'bof');
Dmax = str2double(deblank(char(fread(fid,8,'1*char'))));
%digital maxgain = (Pmax-Pmin)/(Dmax-Dmin); %gain factorif SecLoad == 'all' %if all data needs to be loaded...
RecsLoad = numRec;
else
RecsLoad = ceil(SecLoad/RecDur); %determine how many records need to be loaded
if RecsLoad > numRec
RecsLoad = numRec;
end;
end
fseek(fid,256*(numChan+1),'bof');
%positions the pointer to the beginning of datadata = [];
for ind = 1:RecsLoad
aux = fread(fid,[RecDur*numSam,numChan],'bit24')';
if reshape == 'y'
aux = aux(idx,:);
end;
data = [data, aux];
end;
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