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Snieder, R (author), Wapenaar, C.P.A. (author)
Imaging an unknown object in a medium that is known, such as a medium with constant velocity, is not difficult because one knows exactly where the waves are when they interact with the object. It is much more challenging to image an object in an unknown medium, because in that case one may know the waves that one sends into the medium, but one...
abstract 2016
document
Wapenaar, C.P.A. (author), Snieder, Roel (author), Ridder, Sjoerd de (author), Slob, E.C. (author)
Marchenko redatuming, imaging, monitoring and multiple elimination methods are based on Green’s function representations, with the underlying assumption that the wave field in the subsurface can be decomposed into downgoing and upgoing waves and that evanescent waves can be neglected. In this paper we show that up/down decomposition in the...
book chapter 2021
document
Mulder, W.A. (author)
Since most of the easy hydrocarbon reservoirs have been found, accurate sub-surface imaging for oil and gas exploration and production is crucial. Seismic data can provide a band-limited reconstruction of impedance contrasts between different rock formations as well as a subsurface velocity model. Current compute power allows for the use of the...
conference paper 2012
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Singh, S. (author), Snieder, R. (author), Behura, J. (author), van der Neut, J.R. (author), Wapenaar, C.P.A. (author), Slob, E.C. (author)
Recent work on autofocusing with the Marchenko equation has shown how the Green's function for a virtual source in the subsurface can be obtained from reflection data. The response to the virtual source is the Green's function from the location of the virtual source to the surface. The Green's function is retrieved using only the reflection...
conference paper 2014
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Pont, S.C. (author), Koenderink, J.J. (author), Van Doorn, A.J. (author), Wijntjes, M.W.A. (author), Te Pas, S.F. (author)
We present a novel setup in which real objects made of different materials can be mixed optically. For the materials we chose mutually very different materials, which we assume to represent canonical modes. The appearance of 3D objects consisting of any material can be described as linear superposition of 3D objects of different canonical...
conference paper 2012
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Wapenaar, C.P.A. (author), Van der Neut, J.R. (author), Thorbecke, J.W. (author), Vasconcelos, I. (author), Van Manen, D.J. (author), Ravasi, M. (author)
Despite the close links between the fields of time-reversed acoustics, seismic interferometry and Marchenko imaging, a number of subtle differences exist. This paper reviews the various focusing conditions of these methods, the causality/acausality aspects of the corresponding focusing wavefields, and the requirements with respect to...
conference paper 2014
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Minato, S. (author), Ghose, R. (author)
Hydraulic properties of a fractured reservoir are often controlled by large fractures. In order to seismically detect and characterize them, a high-resolution imaging method is necessary. We apply a non-linear imaging condition to image fractures, considered as non-welded interfaces. We derive the imaging condition from the general correlation...
conference paper 2014
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Thorbecke, J.W. (author), Van der Neut, J.R. (author), Wapenaar, C.P.A. (author)
Recent research showed that the Marchenko equation can be used to construct the Green’s function for a virtual source position in the subsurface. The method requires the reflection response at the surface and an estimate of the direct arrival of the wavefield, traveling from the virtual source location to the acquisition surface. In this paper,...
conference paper 2013
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Agbana, T.E. (author), Soloviev, O. (author), Bezzubik, V. (author), Patlan, V. (author), Verhaegen, M. (author), Vdovin, G.V. (author)
We have implemented an extended depth of field optical system by wavefront coding with a micromachined membrane deformable mirror. This approach provides a versatile extension to standard wavefront coding based on fixed phase mask. First experimental results validate the feasibility of the use of adaptive optics for variable depth wavefront...
conference paper 2015
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Kumar, A. (author), Blacquiere, G. (author), Verschuur, D.J. (author)
Recent advances in survey design have led to conventional common-midpoint-based analysis being replaced by the subsurface-based seismic acquisition analysis and design, with the emphasis on advance techniques of illumination analysis. Amongst them are wave-equation-based seismic illumination analyses such as the so-called focal beam method. The...
conference paper 2014
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Holicki, M.E. (author), Wapenaar, C.P.A. (author), Drijkoningen, G.G. (author)
We propose a novel acoustic decomposition operator for time slices, loosely based on conventional surface decomposition operators. The proposed operators hold for constant velocity models and require two 2D Fourier Transforms (one forward, one backward) per decomposed time slice per decomposition direction. We then demonstrate the capabilities...
conference paper 2016
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Cornel, W.A. (author), Westerweel, J. (author), Poelma, C. (author)
The challenge presented in this research is to determine the local volumetric bubble concentration (or void fraction) in the center of a microbubble cloud with limited optical access and without disturbing the flow. By applying defocused volumetric shadowgraphy to an aerated water column we were able to measure the characteristics of single...
conference paper 2018
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Wilding, D. (author), Pozzi, P. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)
Aberrations, scattering and absorption degrade the performance light-sheet fluorescence microscopes (LSFM). An adaptive optics system to correct for these artefacts and to optimize the light-sheet illumination is presented. This system allows a higher axial resolution to be recovered over the field-of-view of the detection objective. It is...
conference paper 2016
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Wapenaar, C.P.A. (author), van der Neut, J.R. (author), Thorbecke, J.W. (author), Slob, E.C. (author), Singh, Satyan (author)
The homogeneous Green’s function (i.e., the Green’s function and its time-reversed counterpart) plays an important role in optical, acoustic and seismic holography, in inverse scattering methods, in the field of time-reversal acoustics, in reversetime migration and in seismic interferometry. Starting with the classical closed-boundary...
conference paper 2016
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de Ridder, Sjoerd (author), van der Neut, J.R. (author), Curtis, A (author), Wapenaar, C.P.A. (author)
Recently, a novel method to redatum the wavefield in the sub-surface from a reflection response measured at the surface has gained interest for imaging primaries in the presence of strong internal multiples. A prerequisite for the algorithm is an accurate and correct estimate of the direct-wave Green's function. However, usually we use an...
conference paper 2016
document
Perenzoni, M. (author), Cavallo, D. (author)
This paper describes and addresses the challenges that are encountered while designing a 900 GHz antenna for FET detectors using a standard submicron CMOS technology. The reduced metal stack, the problem of surface waves and technology-related rules are taken into account in order to properly design an efficient antenna, with the objective to...
conference paper 2015
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Staal, X.R. (author)
Seismic imaging projects aim to reveal the structure of the earths crust from seismic data. These projects typically include three separate processing steps, being: • attenuation of multiple reflections in the seismic data. • estimating seismic wave propagation velocities from the seismic data. • mapping the measured reflection data to the...
doctoral thesis 2015
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Zhuge, X. (author)
Compact, cost-efficient and high-resolution imaging sensors are especially desirable in the field of short-range observation and surveillance. Such sensors are of great value in fields of security, rescue and medical applications. Systems can be formed for various practical purposes, such as detecting concealed weapons in public places, locating...
doctoral thesis 2010
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Kumar, A. (author)
A seismic survey should be designed such that imaging of the acquired data leads to a sufficiently accurate subsurface image. For that purpose, methods for acquisition geometry analysis and design are available. These methods are used to judge whether an acquisition geometry is suited for the specified objectives. Conventional 2D and 3D...
doctoral thesis 2015
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Montilla, I. (author)
The main goal of this thesis is to develop a system to permit wide field operation of Michelson Interferometers. A wide field of view is very important in applications such as the observation of extended or multiple objects, the fringe acquisition and/ or tracking on a nearby unresolved object, and also to reduce the observation time. For ground...
doctoral thesis 2004
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