1. A method for measuring a physiological parameter, comprising: measuring a plurality of signals, wherein each of said signals comprises a source component corresponding to said physiological parameter and an interference component; processing said plurality of signals to obtain a plurality of principal components; processing said plurality of principal components to obtain a plurality of independent components, wherein a matrix of said plurality of signals corresponds to a matrix product of a matrix of said plurality of independent components and a matrix of mixing coefficients; and extracting a first measure of said physiological parameter corresponding to said source component from one of said plurality of independent components.