File size: 5,078 Bytes
6654bb7 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 |
% Small edits to the EEGLAB file
% Cleaned up and removed irrelevant sections.
%
% eeg_interp() - interpolate data channels
%
% Usage: EEGOUT = eeg_interp(EEG, badchans, method);
%
% Inputs:
% EEG - EEGLAB dataset
% badchans - [integer array] indices of channels to interpolate.
% For instance, these channels might be bad.
% [chanlocs structure] channel location structure containing
% either locations of channels to interpolate or a full
% channel structure (missing channels in the current
% dataset are interpolated).
% method - [string] method used for interpolation (default is 'spherical').
% 'invdist' uses inverse distance on the scalp
% 'spherical' uses superfast spherical interpolation.
% 'spacetime' uses griddata3 to interpolate both in space
% and time (very slow and cannot be interupted).
% Output:
% EEGOUT - data set with bad electrode data replaced by
% interpolated data
%
% Author: Arnaud Delorme, CERCO, CNRS, Mai 2006-
% Copyright (C) Arnaud Delorme, CERCO, 2006, arno@salk.edu
%
% This program is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; if not, write to the Free Software
% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
% $Log: eeg_interp.m,v $
% Revision 1.7 2009/08/05 03:20:42 arno
% new interpolation function
%
% Revision 1.6 2009/07/30 03:32:47 arno
% fixed interpolating bad channels
%
% Revision 1.5 2009/07/02 19:30:33 arno
% fix problem with empty channel
%
% Revision 1.4 2009/07/02 18:23:33 arno
% fixing interpolation
%
% Revision 1.3 2009/04/21 21:48:53 arno
% make default spherical in eeg_interp
%
% Revision 1.2 2008/04/16 17:34:45 arno
% added spherical and 3-D interpolation
%
% Revision 1.1 2006/09/12 18:46:30 arno
% Initial revision
%
function EEG = h_eeg_interp_spl(EEG, badchans, ignore_chans)
if nargin < 2
help eeg_interp;
return;
end;
if ~exist('ignore_chans','var')
ignore_chans=[];
end
badchans = setdiff(badchans,ignore_chans);
if isempty(badchans)
return;
end
goodchans = setdiff(1:EEG.nbchan, badchans);
goodchans = setdiff(goodchans, ignore_chans);
% find non-empty good channels
% ----------------------------
nonemptychans = find(~cellfun('isempty', { EEG.chanlocs.theta }));
goodchans = intersect(goodchans, nonemptychans);
badchans = intersect(badchans, nonemptychans);
fprintf('Interpolating %d channels:', length(badchans));fprintf(' %d',badchans);fprintf('\n');
% scan data points
% ----------------
% get theta, rad of electrodes
% ----------------------------
xelec = [ EEG.chanlocs(goodchans).X ];
yelec = [ EEG.chanlocs(goodchans).Y ];
zelec = [ EEG.chanlocs(goodchans).Z ];
rad = sqrt(xelec.^2+yelec.^2+zelec.^2);
xelec = xelec./rad;
yelec = yelec./rad;
zelec = zelec./rad;
xbad = [ EEG.chanlocs(badchans).X ];
ybad = [ EEG.chanlocs(badchans).Y ];
zbad = [ EEG.chanlocs(badchans).Z ];
rad = sqrt(xbad.^2+ybad.^2+zbad.^2);
xbad = xbad./rad;
ybad = ybad./rad;
zbad = zbad./rad;
EEG.data(badchans,:) = spheric_spline( xelec, yelec, zelec, xbad, ybad, zbad, EEG.data(goodchans,:));
EEG = eeg_checkset(EEG);
function allres = spheric_spline( xelec, yelec, zelec, xbad, ybad, zbad, values)
newchans = length(xbad);
numpoints = size(values,2);
Gelec = computeg(xelec,yelec,zelec,xelec,yelec,zelec);
Gsph = computeg(xbad,ybad,zbad,xelec,yelec,zelec);
% compute solution for parameters C
% ---------------------------------
meanvalues = mean(values);
values = values - repmat(meanvalues, [size(values,1) 1]); % make mean zero
values = [values;zeros(1,numpoints)];
C = pinv([Gelec;ones(1,length(Gelec))]) * values;
clear values;
allres = zeros(newchans, numpoints);
% apply results
% -------------
for j = 1:size(Gsph,1)
allres(j,:) = sum(C .* repmat(Gsph(j,:)', [1 size(C,2)]));
end
allres = allres + repmat(meanvalues, [size(allres,1) 1]);
% compute G function
% ------------------
function g = computeg(x,y,z,xelec,yelec,zelec)
unitmat = ones(length(x(:)),length(xelec));
EI = unitmat - sqrt((repmat(x(:),1,length(xelec)) - repmat(xelec,length(x(:)),1)).^2 +...
(repmat(y(:),1,length(xelec)) - repmat(yelec,length(x(:)),1)).^2 +...
(repmat(z(:),1,length(xelec)) - repmat(zelec,length(x(:)),1)).^2);
g = zeros(length(x(:)),length(xelec));
%dsafds
m = 4; % 3 is linear, 4 is best according to Perrin's curve
for n = 1:7
L = legendre(n,EI);
g = g + ((2*n+1)/(n^m*(n+1)^m))*squeeze(L(1,:,:));
end
g = g/(4*pi);
|