Merge pull request #182 from IrinaNicolae/multiband_ssd

added proc_ssdbank Close #144
bbci · Jul 12, 2016 · e41ed9c · e41ed9c
2 parents d82927b + b1f2891
commit e41ed9c
Showing 1 changed file with 66 additions and 0 deletions.
diff --git a/processing/proc_ssdbank.m b/processing/proc_ssdbank.m
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+function dat = proc_ssdbank(dat, freqs)
+%PROC_SSDBANK - apply Spatio-Spectral Decomposition (SSD) for a  set of
+%frequency bands of interest
+%
+%Synopsis:
+% dat= proc_ssdbank(dat, freqs)
+%
+%Arguments
+%     dat    - data structure of continuous data
+%     freqs  - matrix of frequencies bands of interest (nBands x 2)
+%                 (See example below)
+%             
+%Returns:
+%     dat    - updated data structure
+%
+%Description:
+% applies SSD (Spatio-Spectral Decomposition) on multiple bands and gives the
+% entire bank of decomposed features as output. 
+% The flanking frequencies chosen to supress the noise are set default to 
+% 1 Hz below and 1 Hz above the band of interest(as described in proc_ssd).
+% 
+% Example for FREQS:
+% Frequency bands of interest: 8-10 Hz and 16-18 Hz, then:
+%   freqs = [8 10; 16 18];
+%
+% SEE also proc_ssd, proc_multiBandSpatialFilter
+% 
+% 02-2016: [email protected]
+
+misc_checkType(freqs,'DOUBLE[2 2]');
+
+nBands = length(freqs);
+[T, nChans, nEpochs] = size(dat.x);
+
+% check if data is segmented or continous
+is_epoched = ndims(dat.x) == 3;
+if is_epoched
+    % if the data is segmented (i.e. epoched), then concatenate epochs
+    dat.x = reshape(permute(dat.x, [1,3,2]), [T*nEpochs, nChans]);
+end
+
+% apply SSD on multiple bands
+prev_Nc = 0; xo = [];clab={};
+for ii= 1:nBands,
+    x_ssd = proc_ssd(dat,[freqs(ii,:); freqs(ii,1)-2 freqs(ii,2)+2; freqs(ii,1)-1 freqs(ii,2)+1]); 
+    % put all the SSD features together
+    xo = [xo x_ssd.x];
+    % Update dimensions (needed in case of dimensionality reduction)
+    Nc = size(x_ssd.x,2); 
+    % Assign channels labels corresponding to nBands 
+    clab(prev_Nc+1:prev_Nc+Nc) = cellstr(['_flt' int2str(ii)]);
+    prev_Nc = prev_Nc + Nc;
+end
+
+% put the data back in the correct format 
+if is_epoched
+    xo = permute(reshape(xo, [T, nEpochs, size(xo,2)]), [1,3,2]);
+end
+
+% save old channel labels after SSD
+if isfield(x_ssd,'origClab')
+    dat.origClab = x_ssd.origClab;
+end
+% store the transformed data
+dat.x = xo;
+dat.clab = clab;