eeg_interp_sph_spline_scd - Spherical Spline Scalp Current Density
Useage: [FV,C] = eeg_interp_sph_spline_scd(Zi,Ei)
This function calls eeg_interp_sph_spline,
and replaces the relevant sections from Perrin et al. (1990)
to calculate the scalp current density (SCD).
FV => interpolated spherical surface
FV.faces => triangulation of FV.vertices
FV.vertices => cartesian coordinates (Nx3)
FV.Cdata => spherical spline SCD at FV.vertices
C => interpolation coefficients of Ei (includes co = C(1))
Notes: This function calculates the spherical spline SCD of
Perrin et al (1989). Electroenceph. & Clin.
Neurophysiology, 72: 184-187. Corrigenda (1990),
Electroenceph. & Clin. Neurophysiology, 76: 565.
(see comments in the .m file for details).0001 function [FV,C] = eeg_interp_sph_spline_scd(Zi,Ei) 0002 0003 % eeg_interp_sph_spline_scd - Spherical Spline Scalp Current Density 0004 % 0005 % Useage: [FV,C] = eeg_interp_sph_spline_scd(Zi,Ei) 0006 % 0007 % This function calls eeg_interp_sph_spline, 0008 % and replaces the relevant sections from Perrin et al. (1990) 0009 % to calculate the scalp current density (SCD). 0010 % 0011 % FV => interpolated spherical surface 0012 % 0013 % FV.faces => triangulation of FV.vertices 0014 % FV.vertices => cartesian coordinates (Nx3) 0015 % FV.Cdata => spherical spline SCD at FV.vertices 0016 % 0017 % C => interpolation coefficients of Ei (includes co = C(1)) 0018 % 0019 % Notes: This function calculates the spherical spline SCD of 0020 % Perrin et al (1989). Electroenceph. & Clin. 0021 % Neurophysiology, 72: 184-187. Corrigenda (1990), 0022 % Electroenceph. & Clin. Neurophysiology, 76: 565. 0023 % (see comments in the .m file for details). 0024 0025 % $Revision: 1.1 $ $Date: 2004/11/12 01:32:33 $ 0026 0027 % Licence: GNU GPL, no implied or express warranties 0028 % History: 10/2003 Darren.Weber_at_radiology.ucsf.edu, with 0029 % adapted from eeg_interp_sph_spline 0030 % 0031 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0032 0033 [C,r] = eeg_interp_sph_spline_c(Zi,Ei); 0034 0035 Co = C(1); 0036 Ci = C(2:end); 0037 0038 eegversion = '$Revision: 1.1 $'; 0039 fprintf('EEG_INTERP_SPH_SPLINE_SCD [v %s]\n',eegversion(11:15)); tic 0040 0041 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0042 % Now that C is solved, we can obtain interpolated scalp current density 0043 % at Ej (Eq. 5) 0044 0045 % create spherical interpolation positions 0046 fprintf('...generating spherical interpolation points\n'); 0047 FV = sphere_tri('ico',4,r); 0048 0049 % cosines between measurement electrodes and interpolation points 0050 Cos = elec_cosines(Ei,FV.vertices); 0051 0052 % Calculate h(x) 0053 Hx = eeg_interp_sph_spline_h(Cos,r); % nElectrodes x NinterpolationPoints 0054 0055 % Solve Eq 5. 0056 FV.Cdata = (Ci' * Hx)'; 0057 0058 t=toc; fprintf('...done (%6.2f sec)\n',t); 0059 0060 return