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A new algorithm for a compact mobile four-hydrophone array “RAPID Array” that displays the dolphin's real-time direction data on a graphical user interface (GUI) was proposed to accurately estimate the number of Ganges river dolphins from acoustic data recorded during the census. By considering the trajectory changes in dolphins' click data depending on the time (t) and azimuth (θ) in the coordinate...
The speed of the target can be estimated by the sound pressure cross-correlation of the line spectrum of the moving target at different time intervals. However, a slight deviation of the line spectrum has a significant influence on the estimated result. In this paper this phenomenon is analyzed from the theory, then the speed of the target is estimated when the line spectrum is biased. Experimental...
This paper investigates the consistency in phased array element performance by extracting information from the Full Matrix Capture (FMC) of a reflection from a planar interface. The purpose of this work is to generate a robust methodology for tracking phased array performance over time, therefore, ensuring the reliability of measured data. To achieve this, a calibration method has been developed that...
Explosive charges are widely used in underwater acoustics experiments because it has wide bandwidth and high source level. the received signals are the shock wave and followed by a series of bubble pulses, which seriously affect the observation and applications of the signal. But for the shallow water waveguides, the bubble pulses could be seen as anther “signal”. In this paper, we treat the first...
In this paper method of location determination is proposed for objects that are sources of sound. Authors propose to use beamforming algorithms on data from Microphone arrays and neural-network algorithms for determining the similarity of the results with the typical sound of a given object for this purpose.
This work explores integrating sparse recovery methods into the ray space transform. Sparse recovery methods have proven useful in microphone array analysis of sound fields. In particular, they can provide extremely accurate estimates of source direction in the presences of multiple, simultaneous sources and noise. The ray space transform has recently emerged as a useful tool to analyse sound fields,...
Surveillance tasks, both in the public security and in the military domains, exploit sensors and sensor networks with complementary functionalities. Systems with an integrated multisensory suite benefit from the complementarity of the sensed data types. Capability gaps can indeed be reduced and an enhanced profile of the Area of Interest (AoI) can be retrieved. Although a diversified selection of...
In this paper we propose a method for the localization of acoustic sources using small microphone arrays randomly placed in the acoustic scene. The presented approach is based on a ray-based plane wave decomposition performed locally on each microphone array followed by a fusion of the obtained results in order to build a sound field representation that is convenient for the localization of acoustic...
The backbone of modern infrastructure is concrete, yet modern ultrasonic characterization techniques often fail to be accurate and repeatable. Recent advances in low frequency ultrasonic array hardware have generated a new potential for improved material and structural characterization of concrete. However, the analysis and interpretation associated with the new array based hardware is more difficult...
Recent development of the air-coupled sensing technique provides great potential for practical data measurement in the field; however, an improved data analysis method and careful design of test configuration are required to inspect structures appropriately. Impact-echo (IE) is an efficient method to evaluate delamination-like defects in concrete bridge decks. However, practical application of air-coupled...
An ultrasonic array system is designed for wirelessly powering and communicating with implantable medical devices. A flexible hardware interface is used to drive a 32-element linear phased array with emphasis on programmability and efficiency rather than bandwidth or peak power. Various beam patterns and data modulation schemes are verified at a depth of 6 cm in a tissue phantom with more than sufficient...
Bio-medical ultrasound imaging has recently gained considerable attention. A two-dimensional (2-D) array is essential for three-dimensional (3-D) volumetric imaging. Fully populated 2-D dense array requires thousands of active elements and their interconnections. We present a 2-D CMUT sparse array with 128 elements for 3-D volumetric imaging. This CMUT sparse array with a die size of 6.3 mm × 6.3...
The arrival time detection probability and the measurement range of transit-time ultrasonic flow meters are undermined by the sound drift effect. One solution to this problem is utilizing a phased-array beam steering technique to compensate the bend of the ultrasonic beams. The design, the fabrication and the characterization of two-dimensional flexural ultrasonic phased arrays is investigated in...
Ultrasound (US) therapy is, for a large panel of application, a promising technique which still requires an accurate monitoring system. Therefore, the passive acoustic mapping (PAM) beamforming technique is outlined. It reconstructs cavitation activity maps by beamforming acoustic signals passively recorded by an array. This method has already been explored in 2D with optimizations as phase coherence...
Transit-time ultrasonic flow meters, measuring the time difference between upstream and downstream propagation of ultrasonic beams, have been widely utilized to obtain the average velocity of flow in many applications including natural gas flow rate measurement. The signal-to-noise ratio (SNR) of the ultrasonic signals frequently suffers from the sound drift effect, and thus, the arrival time detection...
We present a fully-populated 8×8 2D-phased array, capable of emitting directed air-coupled ultrasound at 40 kHz with λ/2-pitch size for zero grating lobes. In comparison to our previous work, in which we describe a 1D-phased array, we use 3D-printing to realize the wave guide structure. Besides the key idea to separate the vibrating from the acoustic aperture, the 3D-printing approach allows implementing...
Audio-visual beamforming involves both an acoustic sensor and an omni-camera to form a composite 3D audio-visual representation of the environment. Information from the respective modalities is combined in the process of acoustic localization taking into account high level cognitive features of the signals, namely the presence of specific sounds - speech and tones - which have characteristic signatures...
In this paper we present a source extraction technique for multiple uniform linear arrays distributed in space. The technique adopts the Ray Space Transform representation of the sound field, which is inherently based on the Plane Wave Decomposition. The Ray Space Transform gives us an intuitive representation of the acoustic field, thus enabling the adoption of geometrically-motivated constraints...
Acoustic telemetry is an essential tool for ecological and behavioral analysis of fish and marine mammals in fresh and sea water. However, the accuracy of acoustic telemetry is a challenging problem in that acoustic detection is affected by various environmental factors that govern sound speed and propagation: density, density stratification, mixing, and the environmental processes that control them...
Six years have passed since the Deepwater Horizon oil spill. Work is still ongoing to assess and repair the economic and property damage caused by the accident, which was considered to be the largest accidental marine oil spill in the history of the petroleum industry. An estimated 4.9 million barrels of crude oil leaked into the sea over an 87-day period after the initial explosion.
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