My primary research interests lie in the area of Acoustics and Array Signal Processing. I have worked on many interdisciplinary projects in different areas such as Underwater Acoustics, Bioacoustics, Acoustical Imaging, Room Acoustics, etc.
Please click on a topic for more information.
Array Signal Processing
Array Signal Processing is a research area that uses the data collected by an array of receivers to extract knowledge about the source signal and its location. In my research, I have worked on source signal reconstruction, sound source localization, and beamforming.
Acoustic signals received by an array of receivers can be used for imaging and sound source localization. In my research, I have developed a novel beamforming technique which has higher resolution compared to the existing methods. The main application of this method is biomedical imaging.
The localization of marine mammals is important for biological studies and for assessments of the impact of anthropogenic activities on the marine environment. Passive acoustic monitoring (PAM) has become an increasingly popular method for localizing certain marine mammal species that are acoustically active. I have used both vertical and horizontal hydrophone arrays to find the location of Baleen whales.
- Ranging of Bowhead Whale Calls using a Vertical Array
- Ranging of Baleen Whale Calls using a Long Horizontal Array
- Shima H. Abadi, William S. D. Wilcock, Maya Tolstoy, Timothy J. Crone, Suzanne M. Carbotte:
"Sound source localization using data recorded by hydrophone streamers during seismic surveys", Journal of the Acoustical Society of America,
Seismic surveys are under increasing scrutiny because of concern that they may disturb or otherwise harm marine mammals and impede their
communications. Most of the energy from seismic surveys is low frequency, so the concern about their impact is focused on Baleen whales that
communicate in the same frequency range. In this research study, data is analyzed from a seismic reflection experiment conducted by the
R/V Langseth. Many Baleen whale calls have been recorded by
the horizontal hydrophone array. Figure below shows two examples of Fin whale (higher frequency summer call) and Humpback whale calls.
The first call was recorded during the firing of the mitigation gun (the broadband impulsive signal after the whale call) and the second call was
recorded during a complete shut-down.
I have developed a novel localization technique
which utilizes the seismic hydrophone streamer to detect calling Baleen whales at greater range than possible with existing acoustic monitoring,
and locate the calls to study whale behaviour. The calculated locations confirm the estimated locations reported by observers
during the experiment.
More details in:
- Studying the Impact of Seismic Reflection Surveys on Baleen Whales (coming soon)