Sound field analysis and synthesis in 3D by microphone and loudspeaker arrays, with applications in speech enhancement, spatial audio, spatial hearing, and source localization
Researcher: Boaz Rafaely
Department: Electrical and Computer Engineering
Faculty: Engineering
E-mail: br@ee.bgu.ac.il
Current research focuses on spatial analysis of enclosed sound fields using spherical microphone arrays. These arrays can provide true 3D measurement and analysis, and have become a topic of major international research since 2002, with several special sessions in recent IEEE conferences. Current research in this area involves design and analysis of spherical arrays, development of spatial signal processing algorithms, and experimental investigations in real enclosures. Applications cover a wide range, including speech enhancement, spatial music recordings and reproduction, room acoustics analysis, and noise control.
Some very recent research topics involved the relation between 3D enclosed sound fields and their perception. A sound field captured by a spherical microphone array and reproduced by headphones with head tracking, was used in the investigation of spatial perception of recorded sound fields. This research aims to lead to an understanding of spatially recorded sound fields and the recording requirements that lead to desirable spatial perception.
Another specific topic of interest is the development of algorithms for spherical arrays that facilitate enhancement of signals, such as speech and other sound sources recorded in difficult conditions of significant reverberation and noise. The true 3D capabilities of spherical arrays, together with spherical-harmonics based array processing, could lead the way to signal enhancement under extremely difficult conditions, with applications ranging from telecommunications to security.
The use of remote sensing for rapid response
Researcher: Dan G. Blumberg
Department: Geography and Environmental Development
Faculty: Humanities and Social Sciences
E-mail: blumberg@bgu.ac.il
Natural hazards are unexpected and uncontrollable events of unusual magnitude that threaten daily life and often impact the civil infrastructure and livelihood of a site for many years. Many natural hazards even carry devastating consequences including high death tolls. The tsunami of December 26th, 2004 caused over 220,000 deaths, affected 2.4 million people, and generated an estimated $7.7 billion (US dollars) in damages (EM-DAT). While this natural disaster is one of the most destructive events in recent memory, roughly 600 natural disasters are recorded each year including droughts, floods, earthquakes, storms, landslides, and other severe geological phenomenon. A recent World Bank study estimates that roughly 25 million square kilometers and 3.4 billion people are relatively highly exposed to at least one hazard annually.
In the wake of a disaster, it is paramount to be able to quickly identify the population exposure or risk, and then ensuing loss of life and livelihoods. Similarly, in disaster prone regions, it is important for preparedness and prevention, to establish a baseline of populations at risk and characteristics associated with those populations. Natural hazards, however, pay no regard to national or subnational boundaries. In contrast, demographic information is usually provided on a national basis (when comparisons between countries are made) or on a country-by-country basis, by administrative boundaries. To be most useful in analyses of natural hazards, population data must be transformed into units that are compatible with hazard information and satellite imagery, i.e., a raster format. (Transformation in the other direction, that is, associating the geographic aspects of hazards with the native vector census geography may also be possible, but generally leads to information loss and over simplification (REF)). Remote sensing imagery alongside detailed population data are valuable for identifying hazard vulnerability, assisting with relief efforts, and even mitigating the adverse impacts of natural hazards.
