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Seabed minerals in form of ferromanganese or polymetallic nodules (PMN) have been reported in the Pacific, Atlantic, and Indian oceans. The distribution of these PMN are influenced by several factors, such as the associated topographic undulations, surface chlorophyll levels, sediment type and thickness, and water depth. Traditionally, determination of the existence and the distribution of PMN involves...
This paper proposes using the sparse-recovery (SR) based 2-D multiple-signal classification (MUSIC) to enhance the multi-target detection capability of high-frequency surface wave radars (HFSWRs). Usually, for wide-beam HFSWRs, target detection is first conducted in the range-Doppler spectrum; bearings are then estimated by super-resolution methods, such as MUSIC. Unfortunately, this approach can...
The MUSIC(MUltiple SIgnal Classification) method with high resolution is typically used to estimate far-field source bearing. When the source is located in the near-field, it can be applied by compensating the time-delay difference and the magnitude attenuation using spherical wave rules. However, it has a problem with complex calculations, such as eigen-decomposition of a matrix. In this paper, we...
Underwater acoustic (UA) channel is often affected by strong impulsive noise. In this paper, a compressive sensing based iterative algorithm is proposed to accurately estimate the channel state information and mitigate the impulsive noise, which is important to ensure high-speed data transmission in UA orthogonal frequency-division multiplexing communication systems. By exploiting the sparsity of...
The method of compressive sensing is applied to moving source data created by simulation to estimate the mode wavenumbers, mode depth functions and mode amplitudes without any environmental acoustic information, such as sound speed profile or bottom properties. The method needs in principle only data covering a short range span and is thus applicable to a range-dependent environment to estimate the...
This paper proposes a localization method for wireless sensor nodes that utilize tri-directional coils for near-field magnetic induction (MI) communications. Taking advantage of magnetic field measurements of the tri-directional coils, the proposed localization algorithm uses only two anchor nodes to locate a sensor node in the 3-D space. Assuming each anchor node sequentially transmits the communication...
Accurate estimation of detection/classification performance for sidescan sonar systems in Mine Counter-Measure (MCM) applications is important for informing mission tactics and adapting autonomous behaviors. The approach presented in this paper assumes that detection/classification performance can be estimated solely from historical data collected from similar surveys. This paper introduces an algorithm...
This paper presents the theory of passive localization for underwater sources based on multipath arrival structures. The principles of channel modelling in Ray-theory, determination of eigenrays which connect source and receiver, the information of source range and source depth is included primarily in arrival angles and time delays. The weighted-subspace-fitting (WSF) technique is used to minimize...
In this paper, a joint synchronization and Doppler scaling factor estimation algorithm has been proposed for underwater acoustic communications. The training sequence, which consists of two Zadoff-Chu (ZC) sequences being conjugate with each other, is utilized to synchronize and estimate Doppler scaling factor, time delay and carrier frequency offsets (CFOs). ZC sequences are well designed to show...
A technique is presented for estimating the covariance matrix due to underwater ambient noise by enforcing frequency- and angle-smoothness on the power-angle spectrum underlying an observed sample covariance matrix. This smoothing is achieved through a combination of least-squares fitting procedures and explicit suppression of contributions from discrete broadband emitters. The process preserves contributions...
Enhancement of underwater images and videos is an important task required in several image-based applications like survey, seafloor mapping, telepresence, documentation etc. Color correction or white balance of underwater images is the most challenging issue because of the highly-variable illumination conditions, increasing bluish shift with the depth. Another problem is the low image contrast with...
In this paper we present a proof-of-concept for an hydro acoustic fish-tag position estimation and tracking system. In our field-tested concept, a formation of Unmanned Surface Vehicles (USV) creates a mobile array of low-cost hydro acoustic fish-tag receivers. The array of receivers is able to estimate fish-tag locations and follow the fish on open waters, significantly increasing capabilities as...
Although light field data provides abundant cues for depth estimation, light field depth estimation suffers from occlusion and uncertain edges. In this paper, we propose occlusion robust light field depth estimation using segmentation guided bilateral filtering. First, we calculate refocused images from light field data using digital refocusing. Second, we perform support vector machines (SVM) classification...
In this paper, we propose a new adaptation approach for viewport-adaptive streaming of 360-degree videos over the Internet. The proposed approach is able to systematically decide quality levels of tiles according to user head movements and network conditions by taking into account not only prediction errors but also user head movements in each adaptation interval. Experimental results show that the...
Films seek to elicit emotions in viewers by infusing the story they tell with an affective character or tone - in a word, a mood. In content-based multimedia analysis, considerable effort has been made to develop methods to estimate film affect computationally. However, results have been hampered by a tendency to classify film scenes either by genre or not at all, while other potentially helpful classification...
Three-dimensional (3D) ultrasound is extensively used in obstetrics and gynecology, and realistic rendering results can both enhance the accuracy of diagnosis and facilitate communication between obstetricians and pregnant women. This paper proposes an interactive and realistic rendering method using global illumination effects for 3D ultrasound images with low signal-to-noise-ratio (SNR) values....
Methods based on order statistics are often used in finance, quality control, data and signal processing, especially when signals of interest are immersed in impulsive noise. These allow to include rank information by increasing the dimension of the problem. In large dimension problems, we are usually required to know only the second order statistics. In this article we use a rank-one quadratic measurement...
The paper deals with the estimation method of a carrier and time of arrival by chirp-like phase-coded sequence. The developed estimation method of the carrier and time of arrival is suitable for primary synchronization upon signal detection in phase and frequency modulation modems. This method is of less computational complexity relative to the realization of matched filter assembly. To implement...
The comparative analysis of the efficiency of processing of signals information parameters by the discriminators of tracking meters when exposed non-Gaussian broadband and band-limited noise is carried out. It is shown that when band-limited noise influences the discriminator, the efficiency of non-linear processing is higher and it the band-limited path and it increases with the increase of the signal/noise...
Subspace based techniques for direction of arrival (DOA) estimation need large amount of snapshots to detect source directions accurately. This poses a problem in the form of computational burden on practical applications. The introduction of compressive sensing (CS) to solve this issue has become a norm in the last decade. In this paper, a novel CS beamformer root-MUSIC algorithm is presented with...
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