Blind Deconvolution Using Unconventional Beamforming

When an acoustic wave travels in a medium which encounters the boundary of a second medium, recorded signals by a receiver array (an array of microphones or hydrophones) is commonly distorted by reflected waves from the boundaries. Such recordings are the convolution of the source signal and the impulse response of environment at the time of signal transmission. “Blind deconvolution” is the name given to the task of determining the source signal and the impulse response from array-recorded signals when the source signal and the environment’s impulse response are both unknown. This presentation will describe how the basic physics of sound propagation can be combined with novel nonlinear array-signal processing to recover out-of-band lower- or higher-frequency signal information from finite bandwidth signals. This manufactured signal information can be used for source localization to surpass the usual spatial Nyquist and diffraction limits of the receiving array at in-band signal frequencies. In addition, the manufactured below-band signal information can be exploited to overcome the ill-posed character of blind deconvolution, even when the receiving array is sparse in the signal's frequency band and ordinary beamforming is not useful.