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Curvelet-based non-linear adaptive subtraction with sparseness constraintsHerrmann, Felix J., Moghaddam, Peyman P. January 2004 (has links)
In this paper an overview is given on the application of directional basis
functions, known under the name Curvelets/Contourlets, to various
aspects of seismic processing and imaging, which involve adaptive
subtraction. Key concepts in the approach are the use of (i) directional
basis functions that localize in both domains (e.g. space and angle);
(ii) non-linear estimation, which corresponds to localized muting on
the coefficients, possibly supplemented by constrained optimization. We
will discuss applications that include multiple, ground-roll removal and
migration denoising.
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Separation of primaries and multiples by non-linear estimation in the curvelet domainHerrmann, Felix J., Verschuur, Eric January 2004 (has links)
Predictive multiple suppression methods consist of two main steps: a prediction step, in which multiples are predicted from the seismic data, and a subtraction step, in which the predicted multiples are matched with the true multiples in the data. The last step appears crucial in practice: an incorrect adaptive subtraction method will cause multiples to be sub-optimally subtracted or primaries being distorted, or both. Therefore, we propose a new domain for separation of primaries and multiples via the Curvelet transform. This transform maps the data into almost orthogonal localized events with a directional and spatial-temporal component. The multiples are suppressed by thresholding the input data at those Curvelet components where the predicted multiples have large amplitudes. In this way the more traditional filtering of predicted multiples to fit the input data is avoided. An initial field data example shows a considerable improvement in multiple suppression.
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Curvelet imaging and processing : adaptive multiple eliminationHerrmann, Felix J., Verschuur, Eric January 2004 (has links)
Predictive multiple suppression methods consist of two main steps: a prediction step, in which multiples are predicted from the seismic data, and a subtraction step, in which the predicted multiples are matched with the true multiples in the data. The last step appears crucial in practice: an incorrect adaptive subtraction method will cause multiples to be sub-optimally subtracted or primaries being distorted, or both. Therefore, we propose a new domain for separation of primaries and multiples via the Curvelet transform. This transform maps the data into almost orthogonal localized events with a directional and spatial-temporal component. The multiples are suppressed by thresholding the input data at those Curvelet components where the predicted multiples have large amplitudes. In this way the more traditional filtering of predicted multiples to fit the input data is avoided. An initial field data example shows a considerable improvement in multiple suppression.
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