An Introduction to Underwater Acoustics

Lurton, Xavier

doi:10.1007/978-3-642-13835-5

Cited by 314 publications

(252 citation statements)

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“…According to the relationship of selected CFP coordinates, the problem of target ghosting and dislocation can be solved by the adjustment model as displayed in Equation (2). Meanwhile, the refined adjustment operation is only conducted independently in segmented overlapping areas and the track line constraint is used.…”

Section: Evaluation Of the Mosaic Methodsmentioning

confidence: 99%

“…Thus, the refined adjustment can just be carried out in these overlapping areas, which are determined by the image coordinates. From a practical point of view, the port and starboard sides can be considered independent and the corresponding images are treated as if coming from two one-sided systems [2,3]. For each side, echoes are received by the transducer to form the image.…”

Section: Determination and Segment Of The Overlapping Areamentioning

confidence: 99%

“…Combining the detected CPFs (Xf, Yf ) and selected track line positions (Xc, Yc), the adjustment model based on TPS function is established in Equation (2).…”

Section: Adjustment Model Using Cfps and Track Line Positionsmentioning

confidence: 99%

“…Side-scan sonar (SSS) is the most widely used for remote sensing in water environment. SSS transducer built in a towfish is usually towed behind a surveying vessel by a cable, emits a wide-angle beam and receives the seabed echoes at fixed time intervals in a linear path to form the seabed image simultaneously on port and starboard sides [1][2][3]. SSS images can vividly reflect the seabed targets, topography features and sediment distributions [1,2], which has important applications in underwater target detection [4,5], terrain reconstruction [6,7], underwater navigation and localization [8] and many other fields.…”

Section: Introductionmentioning

confidence: 99%

“…In such a situation, the track line positions are usually reckoned through the vessel positions provided by GNSS and the cable length. Next, the reckoned towfish positions are combined with heading data the data decoding, bottom tracking, radiometric distortion correction, slant range correction and geocoding must be conducted to form the SSS geocoded images with clear seabed targets and coordinates [1][2][3]12]. After these preprocessing steps, radiation aberration and geometric distortion can be weakened and the image pixel coordinates are obtained.…”

Section: Introductionmentioning

confidence: 99%

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Side-Scan Sonar Image Mosaic Using Couple Feature Points with Constraint of Track Line Positions

2018

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Abstract:To obtain large-scale seabed surface image, this paper proposes a side-scan sonar (SSS) image mosaic method using couple feature points (CFPs) with constraint of track line positions. The SSS geocoded images are firstly used to form a coarsely mosaicked one and the overlapping areas between adjacent strip images can be determined based on geographic information. Inside the overlapping areas, the feature point (FP) detection and registration operation are adopted for both strips. According to the detected CFPs and track line positions, an adjustment model is established to accommodate complex local distortions as well as ensure the global stability. This proposed method effectively solves the problem of target ghosting or dislocation and no accumulated errors arise in the mosaicking process. Experimental results show that the finally mosaicked image correctly reflects the object distribution, which is meaningful for understanding and interpreting seabed topography.

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Section: Evaluation Of the Mosaic Methodsmentioning

confidence: 99%

Section: Determination and Segment Of The Overlapping Areamentioning

confidence: 99%

“…Combining the detected CPFs (Xf, Yf ) and selected track line positions (Xc, Yc), the adjustment model based on TPS function is established in Equation (2).…”

Section: Adjustment Model Using Cfps and Track Line Positionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Side-Scan Sonar Image Mosaic Using Couple Feature Points with Constraint of Track Line Positions

2018

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Morphological characterization of coral reefs by combining lidar and MBES data: A case study from Yuanzhi Island, South China Sea

Zhang

Yang

Zhang³

et al. 2017

JGR Oceans

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The correlation between seafloor morphological features and biological complexity has been identified in numerous recent studies. This research focused on the potential for accurate characterization of coral reefs based on high‐resolution bathymetry from multiple sources. A standard deviation (STD) based method for quantitatively characterizing terrain complexity was developed that includes robust estimation to correct for irregular bathymetry and a calibration for the depth‐dependent variablity of measurement noise. Airborne lidar and shipborne sonar bathymetry measurements from Yuanzhi Island, South China Sea, were merged to generate seamless high‐resolution coverage of coral bathymetry from the shoreline to deep water. The new algorithm was applied to the Yuanzhi Island surveys to generate maps of quantitive terrain complexity, which were then compared to in situ video observations of coral abundance. The terrain complexity parameter is significantly correlated with seafloor coral abundance, demonstrating the potential for accurately and efficiently mapping coral abundance through seafloor surveys, including combinations of surveys using different sensors.

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Compositional Signatures in Acoustic Backscatter Over Vegetated and Unvegetated Mixed Sand‐Gravel Riverbeds

2017

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Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high‐frequency, decimeter‐resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand‐gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small‐scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two‐stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain‐scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam‐to‐beam) bed‐sonar geometry, are removed. Then, coherent scales between high‐resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high‐pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low‐frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

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An Introduction to Underwater Acoustics

Cited by 314 publications

References 0 publications

Side-Scan Sonar Image Mosaic Using Couple Feature Points with Constraint of Track Line Positions

Side-Scan Sonar Image Mosaic Using Couple Feature Points with Constraint of Track Line Positions

Morphological characterization of coral reefs by combining lidar and MBES data: A case study from Yuanzhi Island, South China Sea

Compositional Signatures in Acoustic Backscatter Over Vegetated and Unvegetated Mixed Sand‐Gravel Riverbeds

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