Quantitative non-linear ultrasonic imaging of targets with high acoustic impedance contrast—Application to bone imaging

2014 ◽  
Vol 135 (4) ◽  
pp. 2268-2268 ◽  
Author(s):  
Régine Guillermin ◽  
Philippe Lasaygues ◽  
Guy Rabau
Keyword(s):  
Acoustic Impedance ◽  
Ultrasonic Imaging ◽  
Bone Imaging ◽  
Impedance Contrast ◽  
Non Linear

Quantitative non-linear ultrasonic imaging of targets with significant acoustic impedance contrast—An experimental study

2013 ◽  
Vol 134 (2) ◽  
pp. 1001-1010 ◽  
Author(s):  
Régine Guillermin ◽  
Philippe Lasaygues ◽  
Guy Rabau ◽  
Jean-Pierre Lefebvre
Keyword(s):  
Experimental Study ◽  
Acoustic Impedance ◽  
Ultrasonic Imaging ◽  
Impedance Contrast ◽  
Non Linear

Analysis of absorption and dispersion effects in synthetic τ-p seismograms

Geophysics ◽  
1987 ◽  
Vol 52 (8) ◽  
pp. 1033-1047 ◽  
Author(s):  
Ruben D. Martinez ◽  
George A. McMechan
Keyword(s):  
Acoustic Impedance ◽  
Seismic Inversion ◽  
Attenuation Effect ◽  
Dispersion Effects ◽  
Impedance Contrast ◽  
Ocean Sediment ◽  
Reflectivity Method ◽  
P Domain ◽  
Absorption And Dispersion ◽  
Ray Parameter

Analysis of absorption and dispersion effects may be done in intercept time‐ray parameter (τ-p) synthetic seismograms calculated using the slowness formulation of the reflectivity method. Seismograms initially computed in the frequency‐ray parameter (ω-p) domain to incorporate absorption and dispersion effects are then Fourier transformed to the (τ-p) domain. Absorption and dispersion are functions of p. Modeling both simple and more realistic stratigraphic sequences shows the interaction of only velocity and density for infinite Q and the complicated effects added when Q is finite. The observed null reflection at p = 0 for infinite Q is no longer null when Q is finite. For p ≠ 0, the inclusion of absorption and dispersion effects complicates the amplitude and phase of the seismic response. Reflectivity due to Q alone (i.e., at an interface with no impedance contrast), as a function of Q contrast and p, contains interesting variations of amplitude and phase. The responses of three geologically realistic models (a brine sand, a partially saturated gas sand, and an ocean‐sediment interface) demonstrate the cumulative nature of the attenuation effect and how the Q contributions become dominant when the acoustic impedance contrast is small. For large acoustic impedance contrasts, the attenuation effect occurs as an amplitude decay and phase rotation for some (especially high) frequencies. The modeling results suggest that absorption and dispersion effects should be taken into account in seismic inversion. Q estimations (in addition to velocity and density) are particularly desirable in exploration for hydrocarbons because of the sensitivity of Q to lithology and fluid content. Q contributes to the reflectivity information inherent in the seismic data.

Acoustic Impedance Contrast Inversion with Multiplicative Regularization

2021 ◽  
Author(s):  
K. Guo ◽  
J. Li ◽  
X. Chen ◽  
G. Zhu ◽  
D. Liu ◽  
...  
Keyword(s):  
Acoustic Impedance ◽  
Impedance Contrast ◽  
Multiplicative Regularization ◽  
Contrast Inversion

Ultrasonic Imaging of High-contrasted Objects Based on Full-waveform Inversion: Limits under Fluid Modeling

2021 ◽  
Vol 43 (2) ◽  
pp. 88-99
Author(s):  
Luis Espinosa ◽  
Elise Doveri ◽  
Simon Bernard ◽  
Vadim Monteiller ◽  
Régine Guillermin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Acoustic Impedance ◽  
Sound Speed ◽  
Waveform Inversion ◽  
Full Waveform Inversion ◽  
Full Time ◽  
Fluid Medium ◽  
Full Waveform ◽  
Impedance Contrast ◽  
Future Work

Quantitative ultrasound techniques have been previously used to evaluate biological hard tissues, characterized by a large acoustic impedance contrast. Here, we are interested in the imaging of experimental data from different test-targets with high acoustic impedance contrast, using the Full Waveform Inversion (FWI) method to solve the inverse problem. This method is based on high-resolution numerical modeling of the forward problem of interaction between waves and medium, considering the full time series. To reduce the complexity of the numerical implementation, the model considers a fluid medium. Therefore, the aim is to evaluate the precision of the reconstruction under this assumption for materials with a different level of attenuation of shear waves, to study the limits of this hypothesis. Images of the sound speed obtained using the experimental data are presented, and the precision of the reconstruction is evaluated. Future work should include viscoelastic materials.

Nonbright‐spot AVO: Two examples

Geophysics ◽  
1995 ◽  
Vol 60 (5) ◽  
pp. 1398-1408 ◽  
Author(s):  
Christopher P. Ross ◽  
Daniel L. Kinman
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Normal Incidence ◽  
Bright Spot ◽  
Seismic Section ◽  
Amplitude Variation With Offset ◽  
Avo Analysis ◽  
Impedance Contrast ◽  
Seismic Anomalies ◽  
Low Amplitude

The use of amplitude variation with offset (AVO) attribute sections such as the product of the normal incidence trace (A) and the gradient trace (B) have been used extensively in bright spot AVO analysis and interpretation. However, while these sections have often worked well with low acoustic impedance bright spot responses, they are not reliable indicators of nonbright‐spot seismic anomalies. Analyzing nonbright‐spot seismic data with common AVO attribute sections will: (1) not detect the gas‐charged reservoir because of near‐zero acoustic impedance contrast between the sands and encasing shales, or (2) yield an incorrect (negative) AVO product if the normal incidence and gradient values are opposite in sign. We divide nonbright‐spot AVO offset responses into two subcategories: those with phase reversals and those without. An AVO analysis procedure for these anomalies is presented through two examples. The procedure exploits the nature of the prestack response, yielding a more definitive AVO attribute section, and this technique is adaptive to both subcategories of nonbright‐spot AVO responses. This technique identifies the presence of gas‐charged pore fluids within the reservoir when compared to a conventionally processed, relative amplitude seismic section with characteristically low amplitude responses for near‐zero acoustic impedance contrast sands.

Acoustic impedance-based size-independent isolation of circulating tumour cells from blood using acoustophoresis

Lab on a Chip ◽  
2018 ◽  
Vol 18 (24) ◽  
pp. 3802-3813 ◽  
Author(s):  
S. Karthick ◽  
P. N. Pradeep ◽  
P. Kanchana ◽  
A. K. Sen
Keyword(s):  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Acoustic Impedance ◽  
Mononuclear Cells ◽  
Tumour Cells ◽  
Circulating Tumour Cells ◽  
Label Free ◽  
Peripheral Blood Mononuclear ◽  
Impedance Contrast ◽  
Blood Mononuclear Cells

Here, we report a label-free method based on acoustic impedance contrast for the isolation of CTCs from peripheral blood mononuclear cells (PBMCs) in a microchannel using acoustophoresis. Applying this method, we demonstrate the label-free isolation of HeLa and MDA-MB-231 cells from PBMCs.

Investigating depth structure uncertainty for horizontal well placement, Bauer Field, Cooper-Eromanga Basin

2018 ◽  
Vol 58 (2) ◽  
pp. 865
Author(s):  
Erin Shirley
Keyword(s):  
Acoustic Impedance ◽  
Horizontal Well ◽  
Average Depth ◽  
Vertical Wells ◽  
Well Placement ◽  
Secondary Target ◽  
Seismic Resolution ◽  
Western Flank ◽  
Impedance Contrast ◽  
Eromanga Basin

The Bauer Field was discovered in August 2011 on the Western Flank of the Cooper-Eromanga Basin. Bauer 1 discovered an 11 m oil column in the Namur Sandstone, directly overlain by a 4 m oil column in the McKinlay Member. The Bauer Field has been developed by vertical wells targeting the high deliverability Namur Sandstone with the McKinlay Member as a secondary target. In 2017 the decision was made to specifically target the McKinlay Member with a horizontal well, requiring a multi-disciplinary approach to combine geological, geophysical and engineering datasets. The McKinlay Member is 3–5 m in thickness and below seismic resolution with the wavelet being dominated by the larger acoustic impedance contrast produced from the Namur Sandstone. The McKinlay Member depth structure was mapped using various depth conversion methods to investigate the uncertainty in the depth structure expected for the landing of the well and along the lateral section. An average depth surface generated from the different techniques was useful for providing the general form of the structure and was used to predict dip changes along the lateral section. Understanding the uncertainty led to successful well placement of the first horizontal well in the McKinlay Member on the Western Flank.

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