My research interests focus on time-frequency and spectrum analysis of especially non-stationary stochastic processes. An introduction to time-frequency analysis is found here.The main applications are biomedical signals and also signals and sound/speech connected to humans and animals.
A novel matched phase reassignment (MPR) method that gives perfect time-frequency localization of two phase synchronized oscillating transient signals is proposed. The MPR is thereby a time-frequency local measure of phase synchronization and can also be used to measure phase difference between short transient signals. We have compared to commonly used phase estimators, for different types of disturbances. Simulations show that the MPR method outperforms the state-of-the-art methods. An illustrative example of phase difference estimates in ms of transient responses measured from the electrical signals of the brain is shown below. The research is a part of a WASP-Expedition project in collaboration with Bo Bernhardsson, dept of Automatic Control and Mikael Johansson, dept of Psychology, Lund University.
The reassignment technique is used to increase localization for signal components in the time-frequency representation. The technique gives perfect localization for infinite linear chirp-signals, impulses and constant frequency signals but not for short non-stationary signals. Based on the spectrogram using a Gaussian window we propose a scaled reassignment that gives perfect localization for a Gaussian function. To the right an example of two Gaussian components clearly visualized by the scaled reassignment (ScRe-Spect). The method has been applied to estimation of dolphin echo-location signals in a collaboration with Josefin Starkhammar, division of Biomedical Engineering, Lund University.
The project is a part of the e-science collaboration, eSSENCE, and is performed together with Dennis Hasselquist, Bengt Hansson and Maja Tarka at the Department of Biology, Lund University. The project applies to general bird song but is specifically focused on the song of the Great Reed Warbler.
The project is a part of the e-science collaboration, eSSENCE, and is performed together with Mikael Johansson and Ines Bramao at the Department of Psychology, Lund University. The project will develop robust tools to capture the real-time activation of memories in high temporal resolution multi-channel recordings of brain activity.
Master of Science in Electrical Engineering, Lund University, 1989, and Ph.D. in Signal Processing, Lund University, 1996. Docent in Signal Processing, 2004 and Professor in Mathematical Statistics with speciality in Statistical Signal Processing, 2010.
Main supervisor of 4 PhD students, assistant supervisor of 6 PhD students and supervisor of 2 Post Doc.
Member of the board of recruitments, LTH, 2013-2015. Vice coordinator for the program Engineering in Mathematics, LTH, 2013-2015. Head of division Mathematical Statistics, 2008-2012. Member of the board of the strategic research area E-science at LTH, 2013-2014. Member of the board of Lunarc, 2012-2014.
Larger grants: eSSENCE 1350kkr 2018-2020 (co-appl.), eSSENCE 2000kkr 2016-2019, eSSENCE 3500kkr, 2012-2016, VR-621-2011-5813, 2400 kkr, 2012-2014, VR-621-2007-6264, 750 kkr, 2008. VR-621 2004-4692, 1860 kkr, 2005-2007. Researcher in technical science, 'särskild forskare', VR-622-2003 602, 5700 kkr, 2004-2009. VR-621-2001-3120, 1200 kkr, 2002-2003, (co-applicant). VR-621-2001 3119, 1000 kkr, 2002-2003. TFR-271-2000-605, 490 kkr, 2001. TFR-271-1997-627, 1400 kkr, 1998 2000.
Publications of more than 35 international journal papers and over 60 conference papers. Co-author of 6 patents.
Associate editor for IEEE Trans. on Signal Processing, 2008-2010. Regular referee for IEEE Trans. on Signal Processing, Elsevier Signal Processing, IEEE Trans. on Biomedical Engineering, IEEE Trans. on Speech and Audio Processing, Elsevier Medical Engineering and Physics.