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Stability has traditionally been one of the most compelling advantages of implicit methods for seismic wavefield extrapolation. The common 4S-degree, finite difference migration algorithm, for example, is based on an implicit wavefield extrapolation that is guaranteed to be stable. Specifically, wavefield energy will not grow exponentially with depth as the(More)
(a) (b) (c) Figure 1. A seismic image (a) after applying structure-oriented smoothing (b) and semblance (c) filters. ABSTRACT Smoothing along structures apparent in seismic images can enhance these structural features while preserving important discontinuities such as faults or channels. Filters appropriate for such smoothing must seamlessly adapt to(More)
a) b) c) d) Amplitude Figure 1. A recorded seismic shot record before (a) and after (b) warping with large shifts that vary with time and o↵set. Reflections are obscured by two di↵erent ambient bandlimited noise images that have been added to the original and warped shot records. (The rms signal:noise ratio in this example is 1:1.) Shifts (c) computed from(More)
Consider two multi-dimensional digital signals, each with N s samples. For some number of lags N l N s , the cost of computing a single cross-correlation of these two signals is proportional to N s × N l. By exploiting several properties of Gaussian windows, we can compute N s local cross-correlations, again with computational cost proportional to N s ×N l.(More)
BABAR, the detector for the SLAC PEP-II asymmetric e þ e À B Factory operating at the Uð4SÞ resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons(More)
By combining a digital image with a lattice of points called atoms, in which atom coordinates are computed to minimize a potential energy function of the combination, we obtain a mesh suitable for further computations, such as flow simulation. Each atom in the lattice contributes a potential function to an atomic potential field. The image represents(More)
Three-dimensional seismic wavefields may be extrapolated in depth, one frequency at a time by two-dimensional convolution with a circularly symmetric , frequency-and velocity-dependent filter. This depth extrapolation, performed for each frequency independently, lies at the heart of 3-D finite-difference depth migration. The computational efficiency of 3-D(More)
(a) (b) (c) Figure 1. A seismic image (a) and scattered data (b) used in image-guided blended neighbor interpolation (c). ABSTRACT Uniformly sampled images are often used to interpolate other data acquired more sparsely with an entirely different mode of measurement. For example, downhole tools enable geophysical properties to be measured with high(More)