Find onset time that signal exceed the threshold value 'y0'
vb_trigger_onset_pre(y,y0,tpre)
vb_trigger_onset_pre(y,y0,tpre,ymax,twin)
--- main input
y : analog signal
y0 : threshold value
--- condition for event rejection
time to previous event shoud be larger than 'tpre'
'y' value shoud be larger than 'ymax' within 'twin' period, if ymax~=[]
--- Output
ix : extracted onset time index
2009-6-16 Masa-aki Sato
Copyright (C) 2011, ATR All Rights Reserved.
License : New BSD License(see VBMEG_LICENSE.txt)0001 function ix = vb_trigger_onset_pre(y,y0,tpre,ymax,twin) 0002 % Find onset time that signal exceed the threshold value 'y0' 0003 % vb_trigger_onset_pre(y,y0,tpre) 0004 % vb_trigger_onset_pre(y,y0,tpre,ymax,twin) 0005 % --- main input 0006 % y : analog signal 0007 % y0 : threshold value 0008 % --- condition for event rejection 0009 % time to previous event shoud be larger than 'tpre' 0010 % 'y' value shoud be larger than 'ymax' within 'twin' period, if ymax~=[] 0011 % --- Output 0012 % ix : extracted onset time index 0013 % 0014 % 2009-6-16 Masa-aki Sato 0015 % 0016 % Copyright (C) 2011, ATR All Rights Reserved. 0017 % License : New BSD License(see VBMEG_LICENSE.txt) 0018 0019 % find event start (signal exceed the threshold) 0020 ix = vb_trigger_start(y,y0); 0021 0022 if isempty(ix), return; end; 0023 0024 N = length(ix); 0025 % avoid dimension swap for exceptional case 0026 y = y(:); 0027 0028 if nargin == 5 && ~isempty(ymax) && twin > 0 0029 twin = round(twin); 0030 t = 1:twin; 0031 ii = repmat(ix(:)',twin,1) + repmat(t(:),1,N); 0032 ii = min(ii, length(y)); 0033 0034 yy = max(y(ii), [], 1); 0035 0036 jj = find(yy >= ymax); 0037 0038 ix = ix(jj); 0039 end 0040 0041 % time to previous event shoud be larger than tpre 0042 dx = [tpre diff(ix)]; 0043 jj = find(dx >= tpre); 0044 ix = ix(jj) ; 0045