Two-Dimensional High-Frequency and Mid-Frequency Hydrophone Arrays and Recording Systems

OCEANS 2006 ◽  
2006 ◽  
Author(s):  
J.D. Skinner ◽  
G.L. D'Spain ◽  
W.S. Hodgkiss
Keyword(s):  
High Frequency ◽  
Two Dimensional

Despeckling of Sar Images Using Shrinkage of Two-Dimensional Discrete Orthonormal S-Transform

2020 ◽  
pp. 2150023
Author(s):  
Priya R. Kamath ◽  
Kedarnath Senapati ◽  
P. Jidesh
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Relevant Information ◽  
Detection Algorithm ◽  
Two Dimensional ◽  
Sar Images ◽  
S Transform ◽  
Processing Step ◽  
Frequency Components ◽  
Shock Filter

Speckles are inherent to SAR. They hide and undermine several relevant information contained in the SAR images. In this paper, a despeckling algorithm using the shrinkage of two-dimensional discrete orthonormal S-transform (2D-DOST) coefficients in the transform domain along with shock filter is proposed. Also, an attempt has been made as a post-processing step to preserve the edges and other details while removing the speckle. The proposed strategy involves decomposing the SAR image into low and high-frequency components and processing them separately. A shock filter is used to smooth out the small variations in low-frequency components, and the high-frequency components are treated with a shrinkage of 2D-DOST coefficients. The edges, for enhancement, are detected using a ratio-based edge detection algorithm. The proposed method is tested, verified, and compared with some well-known models on C-band and X-band SAR images. A detailed experimental analysis is illustrated.

Discriminating intra-parasequence stratigraphic units from two-dimensional quantitative parameters

2021 ◽  
Vol 91 (8) ◽  
pp. 887-911
Author(s):  
Manuel F. Isla ◽  
Ernesto Schwarz ◽  
Gonzalo D. Veiga ◽  
Jerónimo J. Zuazo ◽  
Mariano N. Remirez
Keyword(s):  
High Frequency ◽  
Two Dimensional ◽  
Facies Associations ◽  
Different Types ◽  
Lateral Extent ◽  
Successive Wave ◽  
Shell Bed ◽  
Definition Of ◽  
High Resolution Sequence Stratigraphy ◽  
Bounding Surfaces

ABSTRACT The intra-parasequence scale is still relatively unexplored territory in high-resolution sequence stratigraphy. The analysis of internal genetic units of parasequences has commonly been simplified to the definition of bedsets. Such simplification is insufficient to cover the complexity involved in the building of individual parasequences. Different types of intra-parasequence units have been previously identified and characterized in successive wave-dominated shoreface–shelf parasequences in the Lower Cretaceous Pilmatué Member of the Agrio Formation in central Neuquén Basin. Sedimentary and stratigraphic attributes such as the number of intra-parasequence units, their thickness, the proportions of facies associations in the regressive interval, the lateral extent of bounding surfaces, the degree of deepening recorded across these boundaries, and the type and lateral extent of associated transgressive deposits are quantitatively analyzed in this paper. Based on the analysis of these quantified attributes, three different scales of genetic units in parasequences are identified. 1) Bedset complexes are 10–40 m thick, basin to upper-shoreface successions, bounded by 5 to 16 km-long surfaces with a degree of deepening of one to three facies belts. These stratigraphic units represent the highest hierarchy of intra-parasequence stratigraphic units, and the vertical stacking of two or three of them typically forms an individual parasequence. 2) Bedsets are 2–20 m thick, offshore to upper-shoreface successions, bounded by up to 10 km long surfaces with a degree of deepening of zero to one facies belt. Two or three bedsets stack vertically build a bedset complex. 3) Sub-bedsets are 0.5–5 m thick, offshore transition to upper-shoreface successions, bounded by 0.5 to 2 km long surfaces with a degree of deepening of zero to one facies belt. Two or three sub-bedsets commonly stack to form bedsets. The proposed methodology indicates that the combination of thickness with the proportion of facies associations in the regressive interval of stratigraphic units can be used to discriminate between bedsets and sub-bedsets, whereas for higher ranks (bedsets and bedset complexes) the degree of deepening, lateral extent of bounding surfaces, and the characteristics of associated shell-bed deposits become more effective. Finally, the results for the Pilmatué Member are compared with other ancient and Holocene examples to improve understanding of the high-frequency evolution of wave-dominated shoreface–shelf systems.

scholarly journals LDRD final report on Bloch Oscillations in two-dimensional nanostructure arrays for high frequency applications.

2008 ◽  
Author(s):  
Sungkwun Kenneth Lyo ◽  
Wei Pan ◽  
John Louis Reno ◽  
Joel Robert Wendt ◽  
Daniel Lee Barton
Keyword(s):  
High Frequency ◽  
Final Report ◽  
Two Dimensional ◽  
Bloch Oscillations ◽  
Nanostructure Arrays

Conservative Finite-Difference Scheme for High-Frequency Acoustic Waves Propagating at an Interface Between Two Media

2012 ◽  
Vol 11 (2) ◽  
pp. 351-366
Author(s):  
J. Staudacher ◽  
É Savin
Keyword(s):  
Phase Space ◽  
Acoustic Waves ◽  
High Frequency ◽  
Numerical Scheme ◽  
Propagation Model ◽  
Uniform Grid ◽  
Two Dimensional ◽  
Reflection And Transmission ◽  
Conservative Finite Difference Scheme ◽  
Homogeneous Media

AbstractThis paper is an introduction to a conservative, positive numerical scheme which takes into account the phenomena of reflection and transmission of high frequency acoustic waves at a straight interface between two homogeneous media. Explicit forms of the interpolation coefficients for reflected and transmitted wave vectors on a two-dimensional uniform grid are derived. The propagation model is a Liouville transport equation solved in phase space.

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