Faculty of Engineering
Christian-Albrechts-University, Kiel
Institute for Circuit and System Theory
Logo der Technischen Fakultät
Research Areas

Speech enhancement and noise reduction of speech signals
  • Speech-model oriented approaches
  • Frequency-domain approaches

Speech coding
  • Source coding at low bitrates (particularly CELP-approaches)
  • Source coding at medium bitrates (e.g. Low-Delay-CELP and RPE-LTP)
  • Channel coding (fault protection of coded speech transmitted via mobile channels)
  • Combined source and channel coding with variable bitrate assignment
  • Transform and sub-band coding

Filter banks
  • FFT and DCT
  • Polyphase filter banks and wavelets
  • Theory and applications of analysis-synthesis systems

Objective assessment of speech quality
  • Extraction of speech-quality related factors from a speech signal
  • Psychoacoustical approaches for the determination of speech quality
  • Implementation of a speech-quality measurement system
  • "In-service non-intrusive measurement devices" (INMD)

Speech-model processes
  • Spherically invariant stochastic processes (SIRP) as model signals for bandlimited (e.g. telephone) speech
  • Extension of SIRPs with short-time properties of speech (e.g. formant and pitch structure) using Markov chains

Voice Conversion
  • Extraction of speaker related features to model the prosody
  • Implementation of a prosodic model within a voice conversion algorithm
  • Implementation of a voice-converion system

Signal-processing applications in medicine
  • Analysis of ECG signals
  • Methods to distinguish sleep stages with ECG signals