locdetrend

  Remove running line fit (using local linear regression)-continuous
  processes
  Usage: data=locdetrend(data,Fs,movingwin)
  Inputs:
  Note that units of Fs, movinwin have to be consistent.
  data         (data as a matrix times x channels or a single vector) 
  Fs           (sampling frequency) - optional. Default 1
  movingwin    (length of moving window, and stepsize) [window winstep] - optional.
                   Default. window=full length of data (global detrend).
                   winstep=window -- global detrend
 
 Output:
 data:         (locally detrended data)

0001 function data=locdetrend(data,Fs,movingwin)
0002 %  Remove running line fit (using local linear regression)-continuous
0003 %  processes
0004 %  Usage: data=locdetrend(data,Fs,movingwin)
0005 %  Inputs:
0006 %  Note that units of Fs, movinwin have to be consistent.
0007 %  data         (data as a matrix times x channels or a single vector)
0008 %  Fs           (sampling frequency) - optional. Default 1
0009 %  movingwin    (length of moving window, and stepsize) [window winstep] - optional.
0010 %                   Default. window=full length of data (global detrend).
0011 %                   winstep=window -- global detrend
0012 %
0013 % Output:
0014 % data:         (locally detrended data)
0015 data=change_row_to_column(data);
0016 [N,C]=size(data);
0017 if nargin < 2 || isempty(Fs); Fs=1; end;
0018 if nargin < 3 || isempty(movingwin); movingwin=[N/Fs N/Fs]; end;
0019 Tw=movingwin(1); Ts=movingwin(2);
0020 if Ts>Tw; error('Use step size shorter than window size'); end;
0021 n=round(Fs*Tw);
0022 dn=round(Fs*Ts);
0023 if ~isreal(data) 
0024   yr=real(data); 
0025   yi=imag(data);
0026   if n==N;
0027      yr=detrend(yr);
0028      yi=detrend(yi);
0029      data=yr+i*yi;
0030   else;
0031      for ch=1:C
0032          tmp=runline(yr(:,ch),n,dn); 
0033          yr=yr-tmp;
0034          tmp=runline(yi(:,ch),n,dn); 
0035          yi=yi-tmp;
0036          data(:,ch)=yr+i*yi;
0037      end;
0038   end;
0039 else
0040   if n==N;
0041      data=detrend(data);
0042   else;
0043      for ch=1:C;
0044          tmp=runline(data(:,ch),n,dn); 
0045          data(:,ch)=data(:,ch)-tmp;
0046      end;
0047   end
0048 end