author = {J. Bitzer and K.U. Simmer},
  year = {2001},
  month = {May},
  title = {Superdirective Microphone Arrays},
  editor = {Brandstein, M.; Ward, D.},
  publisher = {Springer},
  pages = {19-37},
  address={Berlin, Heidelberg, New York},
  abstract={This chapter gives an overview of so-called superdirective beamformers, which can be derived by applying the minimum variance distortionless response (MVDR) principle to theoretically well-defined noise fields, as for example the diffuse noise field. We show that all relevant performance measures for beamformer designs are functions of the coherence matrix of the noise field. Additionally, we present unconstrained and constrained MVDR-solutions using modified coherence functions. Solutions for different choices of the optimization criterion are given including a new solution to optimize the front-to-back ratio. Finally, we present a comparison of superdirective beamformers to gradient microphones and an alternative generalized sidelobe canceller (GSC) implementation of the superdirective beamformer.
  booktitle={Microphone Arrays}