An Entropy Based Method for Local Time-Adaptation of the Spectrogram

  • Marco Liuni
  • Axel Röbel
  • Marco Romito
  • Xavier Rodet
Part of the Lecture Notes in Computer Science book series (LNCS, volume 6684)


We propose a method for automatic local time-adaptation of the spectrogram of audio signals: it is based on the decomposition of a signal within a Gabor multi-frame through the STFT operator. The sparsity of the analysis in every individual frame of the multi-frame is evaluated through the Rényi entropy measures: the best local resolution is determined minimizing the entropy values. The overall spectrogram of the signal we obtain thus provides local optimal resolution adaptively evolving over time. We give examples of the performance of our algorithm with an instrumental sound and a synthetic one, showing the improvement in spectrogram displaying obtained with an automatic adaptation of the resolution. The analysis operator is invertible, thus leading to a perfect reconstruction of the original signal through the analysis coefficients.


adaptive spectrogram sound representation sound analysis sound synthesis Rényi entropy sparsity measures frame theory 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Marco Liuni
    • 1
    • 2
  • Axel Röbel
    • 2
  • Marco Romito
    • 1
  • Xavier Rodet
    • 2
  1. 1.Dip. di Matematica ”U. Dini”Universitá di FirenzeFlorenceItaly
  2. 2.IRCAM - CNRS STMSAnalysis/Synthesis Team 1ParisFrance

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