An orthogonal technique for empirical mode decomposition in Hilbert-Huang transform

First, it is indicated that the intrinsic mode functions (IMF) obtained by the empirical mode decomposition (EMD) are not orthogonal. Then an orthogonal technique based on Gram-Schmidt method is proposed to obtain the complete orthogonal intrinsic mode functions. Three ways of the orthogonal processes are suggested and compared in the paper. Finally, the suggested method is validated through the decomposition of a typical time history. The numerical results show that the orthogonal IMF can be obtained easily by the technique proposed in the paper.