An Improvement in Representation of Audio Signal in Time-Frequency Plane using EMD-2TEMD Based Approach


  • Kazi Mahmudul Hassan Department of Computer Science and Engineering, Varendra University, Rajshahi 6204
  • Md. Ekramul Hamid Department of Computer Science and Engineering, University of Rajshahi, Rajshahi 6205
  • Takayoshi Nakai Department of Electric and Electronic Engineering, Shizuoka University, Hamamatsu-shi



Time-Frequency Representation, HHT, Hilbert Spectrum, EMD, 2T-EMD, Filter Bank, Fractional Gaussian Noise, Independent Subspace Analysis


This study proposed an enhanced time-frequency representation of audio signal using EMD-2TEMD based approach. To analyze non-stationary signal like audio, timefrequency representation is an important aspect. In case of representing or analyzing such kind of signal in time-frequency-energy distribution, hilbert spectrum is a recent approach and popular way which has several advantages over other methods like STFT, WT etc. Hilbert-Huang Transform (HHT) is a prominent method consists of Empirical Mode Decomposition (EMD) and Hilbert Spectral Analysis (HSA). An enhanced method called Turning Tangent empirical mode decomposition (2T-EMD) has recently developed to overcome some limitations of classical EMD like cubic spline problems, sifting stopping condition etc. 2T-EMD based hilbert spectrum of audio signal encountered some issues due to the generation of too many IMFs in the process where EMD produces less. To mitigate those problems, a mutual implementation of 2T-EMD & classical EMD is proposed in this paper which enhances the representation of hilbert spectrum along with significant improvements in source separation result using Independent Subspace Analysis (ISA) based clustering in case of audio signals. This refinement of hilbert spectrum not only contributes to the future work of source separation problem but also many other applications in audio signal processing.


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How to Cite

Hassan, K. M., Hamid, M. E., & Nakai, T. (2016). An Improvement in Representation of Audio Signal in Time-Frequency Plane using EMD-2TEMD Based Approach. Rajshahi University Journal of Science and Engineering, 44, 141–150.