Fredpack—a program package for linear filtering in the frequency domain

Bezvoda, Václav; Ježek, Josef; Segeth, Karel

doi:10.1016/0098-3004(90)90053-v

Cited by 13 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These computations are however faster if a special processor for the discrete Fourier transform is used. Bezvoda et al (1990) have implemented 2-D linear filters in a program package FREDPACK for MS DOS, which can be easily modified for other operating systems.…”

Section: Discussionmentioning

confidence: 99%

Linear filters for solving the direct problem of potential fields

1992

Self Cite

View full text Add to dashboard Cite

One of the major advances of computer science in recent years is the introduction of parallel processors. The efficiency of such devices depends strongly on the symmetry of the algorithms implemented; probably the most efficient are fast Fourier transform‐type (FFT‐type) algorithms. It is possible to show that for these algorithms a SIMD (Single Instruction Multiple Data) processor reduces the number of operations from [Formula: see text] to [Formula: see text] (where N is the number of input data and P is the number of processors) provided that both N and P are integer powers of 2. It thus seems advantageous to reconsider the possible uses of the fast algorithms in geophysics, including those not successful on nonparallel computers (Bezvoda et al., 1986).

show abstract

Section: Discussionmentioning

confidence: 99%

Linear filters for solving the direct problem of potential fields

1992

Self Cite

View full text Add to dashboard Cite

show abstract

“…Directional filtering is typically a process conducted in the Fourier domain of the signal (see Fuller ; Bezvoda et al ; Ferraccioli et al ; Pilkington and Roest for examples). Decorrugation of magnetic data in the direction of data collection has also been shown using wavelet transforms (Fedi and Florio , however Fourier domain methods have the advantage of being ubiquitous in potential field processing and interpretation software packages.…”

Section: The Fourier Transformationmentioning

confidence: 99%

“…Once the bearing of the features to be removed is identified, it is possible to isolate and remove all power from the wavenumbers representing this bearing. This method was presented by Fuller () and Bezvoda et al () and is typically done by selecting a minimum and maximum bearing. Any wavenumbers within this zone are set to zero in the Fourier domain, all other wavenumbers remaining the same.…”

Section: Directional Pass/reject Filtermentioning

confidence: 99%

New approach to directional filtering of near‐surface magnetic data

Cheyney

Hill

Linford

et al. 2012

Near Surface Geophysics

View full text Add to dashboard Cite

Topographical anomalies or compressed areas of soil caused by ploughing or more significant relic features such as ridge and furrow produce a response in near-surface magnetic surveys that are usually identified by their repetitive, linear pattern. While they are accurate recordings of the subsurface magnetic properties and micro-topographical features of the site, it is often the anomalies due to deeper features that are the primary focus of the survey. These target anomalies can be masked by the nearsurface pattern and it is therefore often preferable to remove these from the final presentation of the data.Two routines used for removing these features are common in commercial processing software. These are the directional pass/reject and cosine-taper filters. While these filtering techniques can dramatically improve the clarity of the data image, it is shown here that they make significant changes to the data that remain. As interpretation of near-surface magnetic data moves beyond image analysis towards more quantitative methods, it is important to ensure that the final processed data set represents as close as possible the response to the subsurface features of interest.Here an alternative filtering routine dependant on both the azimuth and power-content of the anomalies is proposed that overcomes the problems encountered by the traditional techniques. It is shown that patterns of agricultural linear anomalies can be removed from the data without significantly changing the properties of the desired responses and therefore quantitative interpretation can be subsequently carried out without the data being significantly compromised by the choice of previous processing techniques. sor offsets from zigzag traverses. However, when it is not possible or convenient to incorporate the direction of unwanted features into the survey design, it becomes necessary to identify and remove them using directional filters during postprocessing.

show abstract

T

Howarth¹

2017

Dictionary of Mathematical Geosciences

View full text Add to dashboard Cite

Fredpack—a program package for linear filtering in the frequency domain

Cited by 13 publications

References 4 publications

Linear filters for solving the direct problem of potential fields

Linear filters for solving the direct problem of potential fields

New approach to directional filtering of near‐surface magnetic data

T

Contact Info

Product

Resources

About