Planar sensor arrays have many advantages including ease of manufacture and low cost. However, when used for photoacoustic (PA) imaging, planar sensors have a limited view of the acoustic field, which means some of the waves from the PA source are not recorded. This results in artifacts in the reconstructed image of the PA source (the initial acoustic pressure distribution). In this paper, we d...

In this abstract, we present a beamforming method for estimating the directions and locations of multiple sources and separating each source’s spectrum from field data collected by a wireless acoustic sensor network. Each acoustic sensor is equipped with four microphones that receive acoustic signals in a timesynchronized manner. The difference in time-of-arrival of proximal signals depends on ...

This part discusses signal processing methods for speech extraction in use with voice communication applications such as personal digital assistants (PDA:s), mobile telephone terminals and personal computers. The speaker will be distant from the device and thus the speech signal entering the device will be subject to reverberation as well as disturbed by background noise. Further more, the comp...

Introduction To meet the threats of quiet submarines and high clutter in the littoral undersea battlespace the Navy is developing high-gain acoustic sensor arrays consisting of a large number of sensors. These arrays are intended to be disposable and completely autonomous over mission times as long as 30 days. They will be deployed by unmanned glider or submarine and are designed to perform a l...

This paper presents an analysis of the acoustic emissions emitted by an underway REMUS-100 autonomous underwater vehicle (AUV) that were obtained near Honolulu Harbor, HI using a fixed, bottom-mounted horizontal line array (HLA). Spectral analysis, beamforming, and cross-correlation facilitate identification of independent sources of noise originating from the AUV. Fusion of navigational record...

In this paper we present experimental results on propagation, coherence, and time delay estimation (TDE) in an acoustic microphone array. The primary goal is to understand the achievable accuracy of acoustic TDE using low-cost, commercial off the shelf (COTS) speakers and microphones. In addition, the experiment seeks to provide an empirical understanding of the effects of center frequency, ban...

We report on an amplitude-division-multiplexed interferometric sensor array for locating acoustic emission. Preliminary experiments were carried out with a modified Mach-Zehnder interferometer consisting of two sensing arms and a reference arm and demonstrated a one-dimensional location accuracy of a few centimeters. The system can be extended for two- and three-dimensional location of acoustic...

The goals of this research included comparisons of standard and novel, non-standard processing techniques on linear arrays of vector sensors, and development of new inversion methods based on information contained in the acoustic vector field. A result of this study is then to show how the additional information contained in the acoustic vector field (pressure and particle velocity) may be used...

The throughput is an important parameter for label-free biosensors. Acoustic resonators like the quartz crystal microbalance have a low throughput because the number of sensors which can be used at the same time is limited. Here we present an array of 64 CMOS-integrated film bulk acoustic resonators. We compare the performance with surface plasmon resonance and the quartz crystal microbalance a...