edf文件读取

function [hdr, record] = edfread(fname, varargin) % Read European Data Format file into MATLAB % % [hdr, record] = edfread(fname) % Reads data from ALL RECORDS of file fname ('*.edf'). Header % information is returned in structure hdr, and the signals % (waveforms) are returned in structure record, with waveforms % associated with the records returned as fields titled 'data' of % structure record. % % [...] = edfread(fname, 'assignToVariables', assignToVariables) % Triggers writing of individual output variables, as defined by % field 'labels', into the caller workspace. % % [...] = edfread(...,'desiredSignals',desiredSignals) % Allows user to specify the names (or position numbers) of the % subset of signals to be read. |desiredSignals| may be either a % string, a cell array of comma-separated strings, or a vector of % numbers. (Default behavior is to read all signals.) % E.g.: % data = edfread(mydata.edf,'desiredSignals','Thoracic'); % data = edfread(mydata.edf,'desiredSignals',{'Thoracic1','Abdominal'}); % or % data = edfread(mydata.edf,'desiredSignals',[2,4,6:13]); % % FORMAT SPEC: Source: http://www.edfplus.info/specs/edf.html SEE ALSO: % http://www.dpmi.tu-graz.ac.at/~schloegl/matlab/eeg/edf_spec.htm % % The first 256 bytes of the header record specify the version number of % this format, local patient and recording identification, time information % about the recording, the number of data records and finally the number of % signals (ns) in each data record. Then for each signal another 256 bytes % follow in the header record, each specifying the type of signal (e.g. % EEG, body temperature, etc.), amplitude calibration and the number of % samples in each data record (from which the sampling frequency can be % derived since the duration of a data record is also known). In this way, % the format allows for different gains and sampling frequencies for each % signal. The header record contains 256 + (ns * 256) bytes. % % Following the header record, each of the subsequent data records contains % 'duration' seconds of 'ns' signals, with each signal being represented by % the specified (in the header) number of samples. In order to reduce data % size and adapt to commonly used software for acquisition, processing and % graphical display of polygraphic signals, each sample value is % represented as a 2-byte integer in 2's complement format. Figure 1 shows % the detailed format of each data record. % % DATA SOURCE: Signals of various types (including the sample signal used % below) are available from PHYSIONET: http://www.physionet.org/ % % % % EXAMPLE 1: % % Read all waveforms/data associated with file 'ecgca998.edf': % % [header, recorddata] = edfRead('ecgca998.edf'); % % % EXAMPLE 2: % % Read records 3 and 5, associated with file 'ecgca998.edf': % % header = edfRead('ecgca998.edf','AssignToVariables',true); % % Header file specifies data labels 'label_1'...'label_n'; these are % % created as variables in the caller workspace. % % Coded 8/27/09 by Brett Shoelson, PhD % brett.shoelson@mathworks.com % Copyright 2009 - 2012 MathWorks, Inc. % % Modifications: % 5/6/13 Fixed a problem with a poorly subscripted variable. (Under certain % conditions, data were being improperly written to the 'records' variable. % Thanks to Hisham El Moaqet for reporting the problem and for sharing a % file that helped me track it down.) % % 5/22/13 Enabled import of a user-selected subset of signals. Thanks to % Farid and Cindy for pointing out the deficiency. Also fixed the import of % signals that had "bad" characters (spaces, etc) in their names. % HEADER RECORD % 8 ascii : version of this data format (0) % 80 ascii : local patient identification % 80 ascii : local recording identification % 8 ascii : startdate of recording (dd.mm.yy) % 8 ascii : starttime of recording (hh.mm.ss) % 8 ascii : number of bytes in header record % 44 ascii : reserved % 8 ascii : number of data records (-1 if unknown) % 8 ascii : duration of a data record, in seconds % 4 ascii : number of signals (ns) in data record % ns * 16 ascii : ns * label (e.g. EEG FpzCz or Body temp) % ns * 80 ascii : ns * transducer type (e.g. AgAgCl electrode) % ns * 8 ascii : ns * physical dimension (e.g. uV or degreeC) % ns * 8 ascii : ns * physical minimum (e.g. -500 or 34) % ns * 8 ascii : ns * physical maximum (e.g. 500 or 40) % ns * 8 ascii : ns * digital minimum (e.g. -2048) % ns * 8 ascii : ns * digital maximum (e.g. 2047) % ns * 80 ascii : ns * prefiltering (e.g. HP:0.1Hz LP:75Hz) % ns * 8 ascii : ns * nr of samples in each data record % ns * 32 ascii : ns * reserved % DATA RECORD % nr of samples[1] * integer : first signal in the data record % nr of samples[2] * integer : second signal % .. % .. % nr of samples[ns] * integer : last signal if nargin > 5 error('EDFREAD: Too many input arguments.'); end if ~nargin error('EDFREAD: Requires at least one input argument (filename to read).'); end [fid,msg] = fopen(fname,'r'); if fid == -1 error(msg) end assignToVariables = false; %Default targetSignals = []; %Default for ii = 1:2:numel(varargin) switch lower(varargin{ii}) case 'assigntovariables' assignToVariables = varargin{ii+1}; case 'targetsignals' targetSignals = varargin{ii+1}; otherwise error('EDFREAD: Unrecognized parameter-value pair specified. Valid values are ''assignToVariables'' and ''targetSignals''.') end end % HEADER hdr.ver = str2double(char(fread(fid,8)')); hdr.patientID = fread(fid,80,'*char')'; hdr.recordID = fread(fid,80,'*char')'; hdr.startdate = fread(fid,8,'*char')';% (dd.mm.yy) % hdr.startdate = datestr(datenum(fread(fid,8,'*char')','dd.mm.yy'), 29); %'yyyy-mm-dd' (ISO 8601) hdr.starttime = fread(fid,8,'*char')';% (hh.mm.ss) % hdr.starttime = datestr(datenum(fread(fid,8,'*char')','hh.mm.ss'), 13); %'HH:MM:SS' (ISO 8601) hdr.bytes = str2double(fread(fid,8,'*char')'); reserved = fread(fid,44); hdr.records = str2double(fread(fid,8,'*char')'); hdr.duration = str2double(fread(fid,8,'*char')'); % Number of signals hdr.ns = str2double(fread(fid,4,'*char')'); for ii = 1:hdr.ns hdr.label{ii} = regexprep(fread(fid,16,'*char')','\W',''); end if isempty(targetSignals) targetSignals = 1:numel(hdr.label); elseif iscell(targetSignals)||ischar(targetSignals) targetSignals = find(ismember(hdr.label,regexprep(targetSignals,'\W',''))); end if isempty(targetSignals) error('EDFREAD: The signal(s) you requested were not detected.') end for ii = 1:hdr.ns hdr.transducer{ii} = fread(fid,80,'*char')'; end % Physical dimension for ii = 1:hdr.ns hdr.units{ii} = fread(fid,8,'*char')'; end % Physical minimum for ii = 1:hdr.ns hdr.physicalMin(ii) = str2double(fread(fid,8,'*char')'); end % Physical maximum for ii = 1:hdr.ns hdr.physicalMax(ii) = str2double(fread(fid,8,'*char')'); end % Digital minimum for ii = 1:hdr.ns hdr.digitalMin(ii) = str2double(fread(fid,8,'*char')'); end % Digital maximum for ii = 1:hdr.ns hdr.digitalMax(ii) = str2double(fread(fid,8,'*char')'); end for ii = 1:hdr.ns hdr.prefilter{ii} = fread(fid,80,'*char')'; end for ii = 1:hdr.ns hdr.samples(ii) = str2double(fread(fid,8,'*char')'); end for ii = 1:hdr.ns reserved = fread(fid,32,'*char')'; end hdr.label = hdr.label(targetSignals); hdr.label = regexprep(hdr.label,'\W',''); hdr.units = regexprep(hdr.units,'\W',''); disp('Step 1 of 2: Reading requested records. (This may take a few minutes.)...'); if nargout > 1 || assignToVariables % Scale data (linear scaling) scalefac = (hdr.physicalMax - hdr.physicalMin)./(hdr.digitalMax - hdr.digitalMin);