Temporal smoothing window function
[weight ,Tindex, Nindex]= ...
vb_overlapped_timewindow_weight(Twindow, Tsample, tsubsamp, mode)
--- Input
Twindow(n,:) = [Tstart(n), Tend(n)] : Start and end for n-th time window
Tsample : Total time sample number in MEG data
tsubsamp : subsampled time index
if tsubsamp = [], tsubsamp = 1:Tsample
mode = 0 : weighted average
= 1 : non-overlapped concatenation is done
current time series of each time windows are concatenated
--- Output
Tindex{n} : n-th window time index in the absolute time index
Nindex{n} : n-th window time index within the subsampled data
weight{n} : n-th window weight for window average
Nsample : # of time sample for calculation
Modified by Taku Yoshioka 2005-07-22
2005/08/16 Modified O. Yamshita
2006/10/3 M. Sato
added non-overlapped concatenation mode
Copyright (C) 2011, ATR All Rights Reserved.
License : New BSD License(see VBMEG_LICENSE.txt)0001 function [weight ,Tindex, Nindex, Nsample] = ... 0002 vb_overlapped_timewindow_weight(Twindow, Tsample, tsubsamp, mode) 0003 % Temporal smoothing window function 0004 % [weight ,Tindex, Nindex]= ... 0005 % vb_overlapped_timewindow_weight(Twindow, Tsample, tsubsamp, mode) 0006 % --- Input 0007 % Twindow(n,:) = [Tstart(n), Tend(n)] : Start and end for n-th time window 0008 % Tsample : Total time sample number in MEG data 0009 % tsubsamp : subsampled time index 0010 % if tsubsamp = [], tsubsamp = 1:Tsample 0011 % mode = 0 : weighted average 0012 % = 1 : non-overlapped concatenation is done 0013 % current time series of each time windows are concatenated 0014 % --- Output 0015 % Tindex{n} : n-th window time index in the absolute time index 0016 % Nindex{n} : n-th window time index within the subsampled data 0017 % weight{n} : n-th window weight for window average 0018 % Nsample : # of time sample for calculation 0019 % 0020 % Modified by Taku Yoshioka 2005-07-22 0021 % 2005/08/16 Modified O. Yamshita 0022 % 2006/10/3 M. Sato 0023 % added non-overlapped concatenation mode 0024 % 0025 % Copyright (C) 2011, ATR All Rights Reserved. 0026 % License : New BSD License(see VBMEG_LICENSE.txt) 0027 0028 if ~exist('mode','var'), mode = 0; end; 0029 0030 Nperiod = size(Twindow,1); 0031 Tbegin = Twindow(:,1); 0032 Tend = Twindow(:,2); 0033 0034 0035 % Temporal subsampling index 0036 if nargin <2 | isempty(tsubsamp), 0037 tsubsamp = 1:Tsample; 0038 end 0039 0040 % Subsampling index flag 0041 Nsample = length(tsubsamp); % # of subsampled data 0042 tflag = zeros(1,Tsample); 0043 tflag(tsubsamp) = 1:Nsample; 0044 0045 % Smoothing time window function by sin^2 0046 w_smooth = cell(Nperiod,1); 0047 0048 % First smoothing window 0049 Tperiod = Tend(1)-Tbegin(1)+1; 0050 w_smooth{1} = ones(1,Tperiod); 0051 0052 % 0053 % Following code is for multiple time windows 0054 % 0055 if Nperiod>=2, 0056 if Tend(1)>Tbegin(2), 0057 Toverlap = Tend(1)-Tbegin(2)+1; 0058 w_smooth{1}((Tperiod-Toverlap+1):Tperiod) ... 0059 = sin((pi/2)*(Toverlap:-1:1)./Toverlap).^2; 0060 end 0061 0062 % Middle smoothing window 0063 for i=2:Nperiod-1 0064 Tperiod = Tend(i)-Tbegin(i)+1; 0065 w_smooth{i} = sin(pi*(1:Tperiod)./Tperiod).^2; 0066 end 0067 0068 % Last smoothing window 0069 Tperiod = Tend(end)-Tbegin(end)+1; 0070 w_smooth{end} = ones(1,Tperiod); 0071 if Tbegin(end)<Tend(end-1), 0072 Toverlap = Tend(end-1)-Tbegin(end)+1; 0073 w_smooth{end}(1:Toverlap) ... 0074 = sin((pi/2)*(1:Toverlap)/Toverlap).^2; 0075 end 0076 end 0077 0078 % Subsampling time index for each time window 0079 Tindex = cell(Nperiod,1); 0080 Nindex = cell(Nperiod,1); 0081 0082 % Time window weighting correction 0083 cnt = zeros(1,Nsample); 0084 0085 % Normalized time window function 0086 weight = cell(Nperiod,1); 0087 0088 % mode = 1 : non-overlapped concatenation 0089 nid = 0; 0090 0091 % Time window loop 0092 for j=1:Nperiod 0093 % Subsampling time index 0094 t1 = Tbegin(j); % start time in this period 0095 t2 = Tend(j); % end time in this period 0096 tt = tflag(t1:t2); % time index flag in this period 0097 id = find( tt > 0 ); % subsampled index 0098 Nid = tt(id); % index within 'tsubsamp' 0099 % Tid = id + t1 -1; % subsampled time index 0100 Tid = tsubsamp(Nid); % subsampled time index 0101 T = length(Tid); 0102 0103 Tindex{j} = Tid; 0104 0105 if mode == 0, 0106 Nindex{j} = Nid; 0107 weight{j} = w_smooth{j}(id); 0108 cnt(Nid) = cnt(Nid) + w_smooth{j}(id); 0109 else 0110 n1 = nid + 1; 0111 n2 = nid + T; 0112 Nindex{j} = n1:n2; 0113 weight{j} = ones(1,T); 0114 nid = n2; 0115 end 0116 end; 0117 0118 % Normalization of weighting function 0119 if mode == 0, 0120 for j=1:Nperiod 0121 weight{j} = weight{j}./cnt(Nindex{j}); 0122 end 0123 else 0124 Nsample = nid; 0125 end 0126 0127 return 0128 %----- END of program -----% 0129 0130 % DEBUG check sum is 1 0131 cnt = zeros(1,Nsample); 0132 0133 for j=1:Nperiod 0134 Nid = Nindex{j}; 0135 cnt(Nid) = cnt(Nid) + weight{j}; 0136 end 0137 0138 subplot(2,2,1); 0139 plot(cnt) 0140 0141 subplot(2,2,2); 0142 0143 for j=1:Nperiod 0144 plot(Nindex{j},weight{j}); 0145 hold on 0146 end 0147 0148 subplot(2,2,3); 0149 0150 for j=1:Nperiod 0151 plot(Nindex{j},Tindex{j},'.'); 0152 hold on 0153 end