scholarly journals A MODIFIED RANSAC METHOD FOR THREE-DIMENSIONAL SCATTERING CENTER EXTRACTION AT A SINGLE ELEVATION

2016 ◽  
Vol 68 ◽  
pp. 89-103
Author(s):  
Qinglin Zhai ◽  
Jiemin Hu ◽  
Xingwei Yan ◽  
Ronghui Zhan ◽  
Jianping Ou ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Scattering Center

Velocity estimates derived from three‐dimensional seismic data

Geophysics ◽  
1983 ◽  
Vol 48 (11) ◽  
pp. 1486-1497 ◽  
Author(s):  
Kwame Owusu ◽  
G. H. F. Gardner ◽  
Wulf F. Massell
Keyword(s):  
Seismic Data ◽  
Constant Velocity ◽  
Three Dimensional ◽  
Logarithmic Scale ◽  
Model Data ◽  
Reconstruction Process ◽  
Input Field ◽  
Scattering Center ◽  
Straight Line ◽  
The Matrix

A new computer algorithm is described by which velocity estimates can be derived from three‐dimensional (3-D) multifold seismic data. The velocity estimate, referred to as “imaging velocity,” is that which best describes the diffraction hyperboloid due to a scatterer. The scattering center is best imaged when this velocity is used in the reconstruction process. The method is based on the 3-D Kirchhoff summation migration before stack. The implementation consists of two basic phases: (1) differentiating the input field traces and resampling them to a logarithmic time scale, and (2) shifting, weighting, and summing each resampled trace to a range of depth levels also chosen on a logarithmic scale. Peak amplitudes in the resulting image matrix give a time T and depth Z from which velocity is obtained using the relation [Formula: see text] The locus of constant velocity is a slanted straight line in the coordinate system of the matrix. In the usual application of migration for velocity analysis, each input trace of N samples is migrated for each of M constant velocity functions requiring [Formula: see text] moveout shift calculations. In the new method presented here, a constant shift is calculated for a given resampled trace, for each depth into which it is summed. This reduces the number of calculations per trace to about N, resulting in a significant improvement in computing efficiency. The operation of the algorithm is illustrated using synthetic and physical model data.

Three dimensional electromagnetic model guided scattering center extraction

2016 ◽  
Author(s):  
CongHui Ma ◽  
GongJian Wen ◽  
JinRong Zhong ◽  
Xiaoliang Yang ◽  
BaiYuan Ding ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Electromagnetic Model ◽  
Scattering Center

Accurate Three-Dimensional Scattering Center Extraction for ISAR Image Using the Matched Filter-Based CLEAN Algorithm

2018 ◽  
Vol E101.B (2) ◽  
pp. 418-425 ◽  
Author(s):  
Dal-Jae YUN ◽  
Jae-In LEE ◽  
Ky-Ung BAE ◽  
Won-Young SONG ◽  
Noh-Hoon MYUNG
Keyword(s):  
Matched Filter ◽  
Three Dimensional ◽  
Scattering Center ◽  
Clean Algorithm

The Study of Three-Dimensional Micro-Motion Feature Extraction of Ballistic Target Based on Netted Radar

2014 ◽  
Vol 530-531 ◽  
pp. 534-539
Author(s):  
Dong Zhang ◽  
Cun Qian Feng ◽  
Ning Ning Tong ◽  
Si San He ◽  
Teng Lei
Keyword(s):  
Feature Extraction ◽  
Three Dimensional ◽  
Motion Feature ◽  
Feature Extraction Method ◽  
Scattering Center ◽  
Motion Features ◽  
Micro Motion ◽  
New Feature ◽  
Motion Characteristics ◽  
Relationship Of

To solve the problem of sliding-type scattering center and the problem of angle limitation of single radar, a kind of method for extracting three-dimensional micro-motion characteristics of ballistic target based on netted radars was proposed. Firstly, A new feature extraction method based on half period delay multiplication was introduced which establishes the relationship of sliding-type scattering center and ideal scattering center, then making use of the expand hough transformation, the parameters of echo signals were extracted. At last, the three-dimensional micro-motion features and the structure features were obtained by solving nonlinear multivariable equation systems which were established by the multi-view of netted radar. Simulation validated the method can get both the high estimating precision and the three-dimensional micro-motion parameters.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

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