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We propose a general approach towards feature extraction for identifying sonar targets based on their composition and geometry. The key idea is to discover the geometric connections between braid-like features within acoustic color topography that includes magnitude and phase information. Specifically, we characterize each target as a graph of intersecting braided features, detected across the complex-valued...
We present a geometry-inspired characterization of target response for active sonar that exploits similarity between intra-class features to distinguish between different targets against environmental objects such as a rock. Key innovation is to represent feature manifolds as a set of ellipsoids, each of which geometrically encompasses a unique physical characteristic of the target's response. We...
We address the long-standing challenge of sonar target identification against weak ground truths and interfering scatter components by harnessing robust topographic elements of target resonance profiles. Our goal is to achieve unknown target discovery when supervised learning is not practical due to ground truth uncertainties. Specifically, we examine topographic manifolds to localize resonance components,...
We address the well-known challenge of detecting a target in non-stationary clutter in active sonar using dynamic time-frequency localization. The challenge is to track a target against non-stationary reverberation from the bottom and sea surface, as well as backscatter from biologics. Definition of "target" is application-specific, e.g. in a Naval application the target would typically...
The Hilbert envelope is a well-known indicator for amplitude modulation in subband time series. However, frequency modulation estimators typically impose temporal smoothness constraints that limit their general use for stochastic signals. We introduce the complementary envelope as a direct indicator of stochastic phase coherence and frequency modulation. Rooted in the second-order statistics of randomly-phased...
Propeller radiated cavitation noise is broadband yet audibly rhythmic, taking on the characteristics of amplitude-modulated noise. The study of this process is important because the shaft and blade rates, as well as other identifying features of the ship, can be inferred from the cavitation signal envelope. Unlike the conventional method for estimating the modulation frequency, this paper proposes...
Motivated by a form of the likelihood-ratio-tesf statistic for detection of a rank-one Gaussian signal in colored Gaussian noise, we apply our earlier technique for estimation of a low-rank signal to the problem of estimating and subtracting the waveform of a strong sinusoidal interference prior to detection of a weak sinusoidal signal. We consider the difficult case in which samples of data are taken...
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