Modification of Kirchhoff migration with variable sound speed and attenuation for tomographic imaging of the breast

2011 ◽  
Author(s):  
Steven P. Schmidt ◽  
Olivier Roy ◽  
Cuiping Li ◽  
Nebojsa Duric ◽  
Zhi-Feng Huang
Keyword(s):  
Sound Speed ◽  
Tomographic Imaging ◽  
Kirchhoff Migration

scholarly journals Modification of Kirchhoff migration with variable sound speed and attenuation for acoustic imaging of media and application to tomographic imaging of the breast

2011 ◽  
Vol 38 (2) ◽  
pp. 998-1007 ◽  
Author(s):  
Steven Schmidt ◽  
Nebojsa Duric ◽  
Cuiping Li ◽  
Olivier Roy ◽  
Zhi-Feng Huang
Keyword(s):  
Sound Speed ◽  
Tomographic Imaging ◽  
Acoustic Imaging ◽  
Kirchhoff Migration

Body surface scanner for the abdominal sound speed tomographic imaging

2012 ◽  
Vol 131 (4) ◽  
pp. 3363-3363
Author(s):  
Akira Yamada ◽  
Kensuke Sasaki ◽  
Toshihiko Yokoyama
Keyword(s):  
Body Surface ◽  
Sound Speed ◽  
Tomographic Imaging

On the imaging of reflectors in the earth

Geophysics ◽  
1987 ◽  
Vol 52 (7) ◽  
pp. 931-942 ◽  
Author(s):  
Norman Bleistein
Keyword(s):  
Reflection Coefficient ◽  
Sound Speed ◽  
Geometrical Optics ◽  
Opening Angle ◽  
Singular Function ◽  
Dirac Delta ◽  
Kirchhoff Migration ◽  
Inversion Operator ◽  
Band Limited ◽  
Reflecting Surface

In this paper, I present a modification of the Beylkin inversion operator. This modification accounts for the band‐limited nature of the data and makes the role of discontinuities in the sound speed more precise. The inversion presented here partially dispenses with the small‐parameter constraint of the Born approximation. This is shown by applying the proposed inversion operator to upward scattered data represented by the Kirchhoff approximation, using the angularly dependent geometrical‐optics reflection coefficient. A fully nonlinear estimate of the jump in sound speed may be extracted from the output of this algorithm interpreted in the context of these Kirchhoff‐approximate data for the forward problem. The inversion of these data involves integration over the source‐receiver surface, the reflecting surface, and frequency. The spatial integrals are computed by the method of stationary phase. The output is asymptotically a scaled singular function of the reflecting surface. The singular function of a surface is a Dirac delta function whose support is on the surface. Thus, knowledge of the singular functions is equivalent to mathematical imaging of the reflector. The scale factor multiplying the singular function is proportional to the geometrical‐optics reflection coefficient. In addition to its dependence on the variations in sound speed, this reflection coefficient depends on an opening angle between rays from a source and receiver pair to the reflector. I show how to determine this unknown angle. With the angle determined, the reflection coefficient contains only the sound speed below the reflector as an unknown, and it can be determined. A recursive application of the inversion formalism is possible. That is, starting from the upper surface, each time a major reflector is imaged, the background sound speed is updated to account for the new information and data are processed deeper into the section until a new major reflector is imaged. Hence, the present inversion formalism lends itself to this type of recursive implementation. The inversion proposed here takes the form of a Kirchhoff migration of filtered data traces, with the space‐domain amplitude and frequency‐domain filter deduced from the inversion theory. Thus, one could view this type of inversion and parameter estimation as a Kirchhoff migration with careful attention to amplitude.

2.5D Algorithm for Tomographic Imaging of the Deep Electromagnetic Geophysical Measurement

PIERS Online ◽  
2006 ◽  
Vol 2 (2) ◽  
pp. 214-218
Author(s):  
Aria Abubakar ◽  
Tarek M Habashy ◽  
V. Druskin ◽  
D. Alumbaugh ◽  
P. Zhang ◽  
...  
Keyword(s):  
Tomographic Imaging ◽  
Geophysical Measurement

Effect of Nada Yoga on Hypertension & Anxiety Level

GIS Business ◽  
2019 ◽  
Vol 14 (6) ◽  
pp. 1-16
Author(s):  
Naveen Kumar ◽  
Kuldeep singh
Keyword(s):  
Sound Speed ◽  
Anxiety Level ◽  
Hatha Yoga ◽  
Significant Difference ◽  
The Subject ◽  
Level Of Significance

In Nada yoga the sound speed of an object vibrates (as well as its size, however infinitesimal) contributes to its particular sound. Different tone and frequencies contains the subject of meditation in Nada Yoga, which also takes into consideration the musical intervals used in music and in the musical recitation of mantras, is brought together with meditation techniques and certain Hatha Yoga practices that are conducive to sonic exploration. Recently a study conducted on anxiety and hypertension level in Raigarh entitled as “The effect of Nada Yoga on Hypertension and anxiety level”.  The outcome of the study shows that Nada Yoga significantly reduces Anxiety as well as Hypertension. Results founds were surprisingly shows a significant difference between the two means, at .01 level of significance. It shows how Nada Yoga can effectively help to reduce anxiety and hypertension as well as many improves in health also.

ANALYSIS OF SOUND SPEED IN LONGITUDINAL DIRECTION AT REFERENCE MOISTURE CONTENT (w = 12 %) IN SAWMILL ASSORTMENTS (FAGUS SYLVATICA, L.)

Akustika ◽  
2020 ◽  
pp. 45-50
Author(s):  
Alena Rohanová
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Sound Speed ◽  
Longitudinal Direction ◽  
Structural Timber ◽  
Sound Speeds ◽  
Dynamic Modulus Of Elasticity ◽  
Round Timber

This paper explores the analysis of sound speeds in the longitudinal direction and their reduction to the reference moisture content w = 12 %. The sound speed cw was determined with Sylvatest Duo device. Moisture content of beech sawmill assortments (round timber: N = 16, logs: N = 2 × 16, structural boards: N = 54) in the range of 12 – 72 % was measured. For the analysis purposes, the sound speed was converted to reference conditions (c12, uref = 12%). A second-degree polynomial (parabola) with a regression equation of the form: c// = 5649 - 27,371 × w + 0.0735 × w2 was used to convert cw to c12, and correction of measured and calculated values was used as well. The sound speeds c12 in sawmill assortments (c12,round, c12,log, c12,board) were evaluated by linear dependences. Dependence was not confirmed for c12,round and c12,board1 (r = 0.168), in contrast for c12,round and c12,log2 the dependence is statistically very significant (r = 0.634). The results of testing showed that the most suitable procedure for predicting quality of structural timber is the first step round timber – log2, the second step: log2 - board2. More exact results of the construction boards were obtained from log2 than from log1. The sound speed is used in the calculation of dynamic modulus of elasticity (Edyn). EN 408 mentions the possibility of using dynamic modulus of elasticity as an alternative method in predicting the quality of structural timber.

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