When interpolation-induced reflection artifact meets time-frequency analysis

Yu Ting Lin, Patrick Flandrin, Hau Tieng Wu

Research output: Contribution to journalArticlepeer-review


Objective: While extracting the temporal dynamical features based on the time-frequency analyses, like the reassignment and synchrosqueezing transform, attracts more and more interest in biomedical data analysis, we should be careful about artifacts generated by interpolation schemes, in particular when the sampling rate is not significantly higher than the frequency of the oscillatory component we are interested in. Methods: We formulate the problem called the reflection effect and provide a theoretical justification of the statement.We also show examples in the anesthetic depth analysis with clear but undesirable artifacts. Results: The artifact associated with the reflection effect exists not only theoretically but practically as well. Its influence is pronounced when we apply the time-frequency analyses to extract the time-varying dynamics hidden inside the signal. Conclusion: We have to carefully deal with the artifact associated with the reflection effect by choosing a proper interpolation scheme.

Original languageEnglish (US)
Article number7361992
Pages (from-to)2133-2141
Number of pages9
JournalIEEE Transactions on Biomedical Engineering
Issue number10
StatePublished - Oct 2016


  • Cubic spline (CS) interpolation
  • Electrocardiogram (ECG)-derived respiratory signal
  • Instantaneous heart rate (IHR)
  • Nonuniform sampling
  • Reassignment method
  • Synchrosqueezing transform (SST)

ASJC Scopus subject areas

  • Biomedical Engineering


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