Difference between revisions of "Exporting Data from Matlab to BESA Statistics"

%% Export single trial data for condition 1
 
NumChannels = size(timelock_cond1.avg, 1);
NumTrials = size(timelock_cond1.trial, 1);
 
% the output directory
custom_path = 'D:\Data\C1';
% Multiply by 1000 to get the time in milliseconds.
time_samples = timelock_cond1.time.*1000;
channel_labels = timelock_cond1.label;
data_scale_factor = 1.0;
time_scale_factor = 1.0;
 
for iTr = 1:NumTrials
 
    % The file name where data should be written.
    file_name = ['Condition1Trial' num2str(iTr) '.avr'];
    % Multiply by 1e15 to get the data in femtoTesla.
    data_matrix = squeeze(timelock_cond1.trial(iTr, :, :)).*1e15;
 
    % Save the data
    besa_save2Avr(custom_path, file_name, data_matrix, time_samples, ...
        channel_labels, data_scale_factor, time_scale_factor);
 
end
 
%% Export single trial data for condition 2
 
NumTrials = size(timelock_cond2.trial, 1);
 
% the output directory
custom_path = 'D:\Data\C2';
% Multiply by 1000 to get the time in milliseconds.
time_samples = timelock_cond2.time.*1000;
channel_labels = timelock_cond2.label;
data_scale_factor = 1.0;
time_scale_factor = 1.0;
 
for iTr = 1:NumTrials
 
    % The file name where data should be written.
    file_name = ['Condition2Trial' num2str(iTr) '.avr'];
    % Multiply by 1e15 to get the data in femtoTesla.
    data_matrix = squeeze(timelock_cond2.trial(iTr, :, :)).*1e15;
 
    % Save the data
    besa_save2Avr(custom_path, file_name, data_matrix, time_samples, ...
        channel_labels, data_scale_factor, time_scale_factor);
 
end

%% Rearrange channels in grad
 
SortedCoordinates = zeros(NumChannels, 3);
 
NumBadChannels = 1; % A106
 
for iCh1 = 1:NumChannels
 
    CurrLabel1 = timelock_cond1.label{iCh1};
 
    for iCh2 = 1:NumChannels+NumBadChannels
 
        CurrLabel2 = timelock_cond1.grad.label{iCh2};
 
        if(strcmp(CurrLabel1, CurrLabel2))
 
            SortedCoordinates(iCh1, :) = timelock_cond1.grad.chanpos(iCh2, :);
 
        end
 
    end
 
end

%% Transform to spherical coordinates
 
SphericalCoords = zeros(NumChannels, 3);
 
% Create a matrix for rotation about the z-axis.
Angle1 = -90;
rotate1 = [cosd(Angle1) -sind(Angle1) 0; sind(Angle1) cosd(Angle1) 0; 0 0 1];
 
% Perform rotation.
RotatedPositions = SortedCoordinates*rotate1;
 
for iCh = 1:NumChannels
 
    % Get the current coordinates and normalize the radius to 1.0.
    CurrCartesianCoords = RotatedPositions(iCh, :) / ...
        sqrt(sum(RotatedPositions(iCh, :).^2));
    % Perform the transformation from Cartesian to spherical coordinates.
    [azimuth, elevation, r] = besa_transformCartesian2Spherical( ...
        CurrCartesianCoords(1), CurrCartesianCoords(2), ...
        CurrCartesianCoords(3));
    % Assign the transform values to the output matrix.
    SphericalCoords(iCh, 1) = azimuth;
    SphericalCoords(iCh, 2) = elevation;
    SphericalCoords(iCh, 3) = r;
 
end

%% Export elp-file
 
% the output directory
custom_path = 'D:\Data';
% The file name where data should be written.
file_name = 'Subject1.elp';
% The type of the channels to be stored.
channel_type = 'MEG';
 
status = besa_save2Elp(custom_path, file_name, ...
    SphericalCoords, channel_labels, channel_type);