1-20 OF 507 RESULTS FOR

wiener filters

Results shown limited to content with bounding coordinates.
Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
×Close Modal
Sort by
Journal Article
Journal: Geophysics
Published: 18 September 2012
Geophysics (2012) 77 (6): V183-V192.
... tractable narrow-band filter designs, using a 1D complex wavelet frame. This decomposition enables a single-pass adaptive subtraction via complex, single-sample (unary) Wiener filters, consistently estimated on overlapping windows in a complex wavelet transformed domain. Each unary filter compensates...
FIGURES | View All (10)
Journal Article
Journal: Geophysics
Published: 25 November 2009
Geophysics (2009) 74 (6): V133-V141.
... local earthquakes will benefit from reduced noise levels and the ability to detect smaller events will be increased. We propose a frequency-dependent multichannel Wiener filtering technique with linear constraints that uses an adaptive least-squares method to remove coherent noise in seismic array data...
FIGURES | View All (9)
Journal Article
Journal: The Leading Edge
Published: 01 February 2008
The Leading Edge (2008) 27 (2): 232-238.
... excluded) if the noise were completely incoherent. However, actual stacking only improved SNR by 3–6 dB, caused by partially constructive noise interference. When the noise is coherent and distinct from the signal, we can do better. In this section, we apply the multichannel Wiener filter to three...
FIGURES | View All (8)
Journal Article
Journal: Geophysics
Published: 01 June 1996
Geophysics (1996) 61 (3): 882-890.
...Milton J. Porsani Abstract Two recursive algorithms for designing discrete Wiener filters for wavelets of different phase characteristics are the Simpson and the Manolakis recursions. Both procedures are efficient; however, both recursions work with a prefixed length filter. Two fast algorithms...
Journal Article
Journal: Geophysics
Published: 01 July 1983
Geophysics (1983) 48 (7): 887-899.
...Samuel H. Bickel; D. R. Martinez Abstract When Wiener filters are applied to seismic data, the bandwidth of noise increases along with the bandwidth of the signal. Thus the signal-to-noise ratio is degraded. To reduce signal ambiguity it is common practice to prewhiten the Wiener filter...
Journal Article
Journal: Geophysics
Published: 01 August 1975
Geophysics (1975) 40 (4): 617-620.
...P. J. Gunn Abstract It is possible to design multichannel Wiener filters to simultaneously process gravity and magnetic data in profile form so as to produce diagnostic rectangular wave outputs only if anomalies due to bodies with a specified density-magnetization ratio are input. This method has...
Journal Article
Journal: Geophysics
Published: 01 April 1973
Geophysics (1973) 38 (2): 310-326.
...R. J. Wang; S. Treitel Abstract The normal equations for the discrete Wiener filter are conventionally solved with Levinson's algorithm. The resultant solutions are exact except for numerical roundoff. In many instances, approximate rather than exact solutions satisfy seismologists' requirements...
Journal Article
Journal: Geophysics
Published: 01 April 1972
Geophysics (1972) 37 (2): 235-259.
... and the frequency content of individual signal and noise wavelets (events) on these traces. Therefore, a so-called “wavelet” Wiener filter is introduced which suppresses “noise” wavelets and enhances “signal” wavelets; this filter can be contrasted with an ordinary Wiener filter which discriminates between signal...
Journal Article
Published: 01 June 1986
Bulletin of the Seismological Society of America (1986) 76 (3): 847-864.
...H. J. Hwang; B. J. Mitchell Abstract A new technique which combines frequency-domain Wiener filtering and modal isolation is developed for determining interstation phase velocities, group velocities, and attenuation coefficients for seismic surface waves. Frequency-domain Wiener filtering is more...
Journal Article
Journal: Geophysics
Published: 01 February 1988
Geophysics (1988) 53 (2): 186-191.
...A. T. Walden Abstract Deconvolution in the presence of additive noise is a well known problem for which there exists a Wiener filter which spectrally whitens while also suppressing the noise. A simple variant of this standard Wiener filter incorporates a parameter p which is intended to allow...
Journal Article
Journal: Geophysics
Published: 01 October 1969
Geophysics (1969) 34 (5): 683-695.
... to the calculation of time-varying Wiener filters. The Berndt and Cooper technique produces an upper bound for the mean-square error between the true and a given approximated time-varying correlation function. The minimization of this upper bound leads to a relation which enables one to establish gate lengths...
Journal Article
Journal: Geophysics
Published: 01 May 1990
Geophysics (1990) 55 (5): 539-548.
...R. S. Pawlowski; R. O. Hansen Abstract We introduce a gravity anomaly separation method based on frequency-domain Wiener filtering. Gravity anomaly separation can be effected by such wavelength filtering when the gravity response from the geologic feature of interest (the signal) dominates one...
Journal Article
Journal: Geophysics
Published: 01 August 1987
Geophysics (1987) 52 (8): 1138-1148.
...Bo Holm Jacobsen Abstract Separation filtering is incomplete even under the ideal synthetic condition of known power spectra of the regional and residual fields. I have designed some Wiener filters, which minimize the inevitable separation error, from previous statistical source models of Naidu...
Journal Article
Published: 01 December 2011
Bulletin of the Seismological Society of America (2011) 101 (6): 2887-2896.
...J. Wang; J. Schweitzer; F. Tilmann; R. S. White; H. Soosalu Abstract Seismic arrays for detection of small earthquakes benefit from array processing aimed at reducing noise levels. We present a frequency-dependent multichannel Wiener filtering ( MCWF ) technique, which employs an adaptive least...
FIGURES | View All (10)
Journal Article
Journal: Geophysics
Published: 01 August 1976
Geophysics (1976) 41 (4): 659-672.
... the number of sub-filters N according to the formula 2 N - 1. The Wiener filter is an optimum filter in the least-squares sense but its errors occur across the output. The new filter is an optimum filter in an 'error-distribution' sense. Its errors are in reality the noncentral spikes of the spike sequence...
Journal Article
Journal: Geophysics
Published: 01 April 1974
Geophysics (1974) 39 (2): 169-173.
...Sven Treitel Abstract The ordinary time or space domain Wiener filter is conventionally obtained for real-valued inputs and real-valued desired outputs. Situations exist for which these variables are complex-valued.It is possible to develop a solution for the resulting complex Wiener filter...
Journal Article
Journal: Geophysics
Published: 01 April 1975
Geophysics (1975) 40 (2): 358-359.
... normal equations were also derived: ∑ m = 0 N f N ( m Δ t ) R x , x [ ( n − m ) Δ t ] = R x , y ( d ) ( n Δ t ) for n = 0, 1, …, N . In (1a), R x,x (t) is the autocorrelation function of a complex input signal x ( t ), f N ( t ) is the complex least-squares filter of duration ( N + 1)Δ t, y (d) ( t...
Image
A synthetic data application of <b>Wiener</b> <b>filtering</b>. (a) Synthetic trace inclu...
Published: 01 February 2008
Figure 2. A synthetic data application of Wiener filtering. (a) Synthetic trace including only four spikes, (b) ground-roll model (black solid line) and estimated ground roll (dashed red line), (c) noisy data calculated by adding (a) with (b), (d) corresponding spectra of signals in (b) and (c
Image
Comparison of the spectra of the <b>Wiener</b>-<b>filtered</b> output results from the sp...
Published: 01 February 2008
Figure 4. Comparison of the spectra of the Wiener-filtered output results from the spike test (A S /A N =2). The transfer functions generated from noise data are applied on the raw noise data only, and the transfer functions generated from semisynthetic data are applied on the synthetic signal
Image
Experimental HRTEM image (<b>Wiener</b>-<b>filtered</b>) and simulated contrasts for para...
Published: 01 August 2007
F igure 4. Experimental HRTEM image (Wiener-filtered) and simulated contrasts for paragonite and its dehydroxylate. The thickness and defocus value for the simulation are 2.5 nm and −40 nm, respectively. Note that the relative position between adjacent layers (cf. white vertical lines