A statistical technique for high amplitude noise detection: Application to swell noise attenuation

2008 ◽  
Author(s):  
Maïza Bekara ◽  
Analiese Ferreira ◽  
Mirko van der Baan
Keyword(s):  
High Amplitude ◽  
Statistical Technique ◽  
Noise Attenuation ◽  
Noise Detection ◽  
Amplitude Noise

High-amplitude noise detection by the expectation-maximization algorithm with application to swell-noise attenuation

Geophysics ◽  
2010 ◽  
Vol 75 (3) ◽  
pp. V39-V49 ◽  
Author(s):  
Maïza Bekara ◽  
Mirko van der Baan
Keyword(s):  
Expectation Maximization ◽  
Main Idea ◽  
Threshold Value ◽  
High Amplitude ◽  
Noise Power ◽  
Noise Attenuation ◽  
Noise Detection ◽  
Data Set ◽  
Amplitude Noise ◽  
Probability Threshold

High-amplitude noise is a common problem in seismic data. Current filtering techniques that target this problem first detect the location of the noise and then remove it by damping or interpolation. Detection is done conventionally by comparing individual data amplitudes in a certain domain to a user-controlled local threshold. In practice, the threshold is optimally tuned by trial and error and is often changed to match the varying noise power across the data set. We have developed an automatic method to compute the appropriate threshold for high-amplitude noise detection and attenuation. The main idea is to exploit differences in statistical properties between noise and signal amplitudes to construct a detection criterion. A model that consists of a mixtureof two statistical distributions, representing the signal and the noise, is fitted to the data. Then it is used to estimate the probability (i.e., likelihood) that each sample in the data is noisy by means of an expectation-maximization (EM) algorithm. Only those samples with a likelihood greater than a specific threshold are considered to be noise. The resulting probability threshold is better adapted to the data compared to a conventional amplitude threshold. It offers the user, through the probability threshold value, the possibility to quantify the confidence in whether a large amplitude anomaly is considered as noise. The method is generic; however, our work develops and implements the method for swell-noise attenuation. Initial results are encouraging, showing slightly better performance than an optimized conventional method but with much less parameter testing and variation.

Lateral prediction for noise attenuation by t-x and f-x techniques

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1887-1896 ◽  
Author(s):  
Ray Abma ◽  
Jon Claerbout
Keyword(s):  
Random Noise ◽  
High Amplitude ◽  
Noise Attenuation ◽  
Space Domain ◽  
Frequency Space ◽  
Amplitude Noise ◽  
Time Space ◽  
Domain Prediction ◽  
Prediction Techniques ◽  
Prediction Filter

Attenuating random noise with a prediction filter in the time‐space domain generally produces results similar to those of predictions done in the frequency‐space domain. However, in the presence of moderate‐ to high‐amplitude noise, time‐space or t-x prediction passes less random noise than does frequency‐space, or f-x prediction. The f-x prediction may also produce false events in the presence of parallel events where t-x prediction does not. These advantages of t-x prediction are the result of its ability to control the length of the prediction filter in time. An f-x prediction produces an effective t-x domain filter that is as long in time as the input data. Gulunay’s f-x domain prediction tends to bias the predictions toward the traces nearest the output trace, allowing somewhat more noise to be passed, but this bias may be overcome by modifying the system of equations used to calculate the filter. The 3-D extension to the 2-D t-x and f-x prediction techniques allows improved noise attenuation because more samples are used in the predictions, and the requirement that events be strictly linear is relaxed.

Effects of modifications of the crackle percept in high-amplitude noise on sound quality and statistical metrics

2017 ◽  
Vol 141 (5) ◽  
pp. 3879-3879
Author(s):  
S. Hales Swift ◽  
Kent L. Gee ◽  
Tracianne B. Neilsen ◽  
Micah Downing ◽  
Michael M. James
Keyword(s):  
Sound Quality ◽  
High Amplitude ◽  
Amplitude Noise ◽  
Statistical Metrics

Harmonic distortion on a seismic reflection profile across the Quebec Appalachians: relation to Bouguer gravity and implications for crustal structure

1984 ◽  
Vol 21 (3) ◽  
pp. 346-353 ◽  
Author(s):  
Frederick A. Cook
Keyword(s):  
Seismic Reflection ◽  
Far East ◽  
Harmonic Distortion ◽  
High Amplitude ◽  
Seismic Reflection Profile ◽  
Bouguer Gravity ◽  
Seismic Reflection Data ◽  
Arrival Times ◽  
Amplitude Noise ◽  
Reflection Data

Seismic reflection data obtained across the Quebec Appalachians using the VIBROSEIS (trademark Conoco) technique were recorded with parameters that allowed harmonic distortion arrivals to interfere with layered reflections. The data exhibit reflections from layered miogeoclinal rocks dipping eastward beneath the allochthonous rocks of the orogen; the layering appears to terminate beneath the Notre Dame Anticlinorium. However, as the apparent termination of the layers also occurs at the arrival times of high-amplitude noise harmonics, it may have no geological significance. Precambrian Grenville crust, which probably underlies the layered sediments, extends at least as far east as the apparent termination, and may extend much farther. Examination of the Bouguer gravity field in relation to the seismic reflection data shows that a major gravity change is due to density differences that occur considerably west of the eastern limit of Precambrian Grenville crust. The gravity thus shows no correlation with surface structures proposed as suture zones. An actualistic model incorporates subduction of a passive (Atlantic-type) margin beneath an arc terrain during the Ordovician.

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