function out = preprocessingQRSdetection(in, fs, mode)
% preprocessing of ecg signal for QRS detector published in [1]
% (c) Jakub Kuzilek, Lenka Lhotska
% http://bio.felk.cvut.cz/~kuziljak/ E-mail: jakub.kuzilek@gmail.com
% Version: 1.0 Last update: 07/01/2013.
% (Version: 1.0, 07/01/2013)
%
%======================================================
%
% PURPOSE: This function preprocess ECG signal in order to obtain
% complex lead data.
%
% MANDATORY INPUT ARGUMENTS
% in ..... input data MxN, M - length of data, N - number of leads
% fs ..... sampling frequency in Hz
% mode ... 0 - Christov, 1 - Christov + ICA
% OPTIONAL INPUT ARGUMENTS
% none
% OUTPUT ARGUMENTS
% out .... complex lead signal
%=========================================================
%
% Related Bibliography:
%
% [1] Kuzilek J, Lhotska L. Electrocardiogram beat detection
% enhancement using independent component analysis. Medical
% Engineering and Physics. 2012.
%
%=========================================================
in = in-ones(size(in,1),1)*mean(in); % remove mean
out = movingAverage(in, fs, 50); % remove grid noise
out = movingAverage(out, fs, 35); % remove muscle noise
if (mode)
out = performICA(out);
out = movingAverage(out, fs, 50); % remove grid noise
out = movingAverage(out, fs, 35); % remove muscle noise
end
out = complexL(out); % transform to complex lead
out = movingAverage(out, fs, 25); % remove transforming noise