Quantitative evaluation of deep and shallow tissue layers' contribution to fNIRS signal using multi-distance optodes and independent component analysis

► Method for evaluating deep/shallow-tissue contribution to fNIRS signal is proposed. ► We assume both deep and shallow signals are linear combinations of multiple sources. ► Multi-distance optodes and ICA are combined for the proposed method (MD-ICA). ► The method is demonstrated with a dynamic phantom and human brain measurements. ► MD-ICA can be applied to data that is highly correlated between deep/shallow signals.