Browsing by Author "Drijkoningen, Guy G"

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    Decomposition of seismic signals via time-frequency representations
    (1996-01-15) Tobback, Tom; Steeghs, Philippe; Drijkoningen, Guy G; Fokkema, Jacob T; Digital Signal Processing (http://dsp.rice.edu/)
    In this paper we discuss the use of a time-frequency representation, the Wigner distribution, for the decomposition and characterization of seismic signals. The advantage of the Wigner distribution over other representations, such as the wavelet and sliding window Fourier transform, is its sharp localization properties in the time-frequency plane. However, the Wigner distribution is a not a linear transformation. This non-linearity complicates the use of the Wigner distribution for time-frequency filtering and decomposition. We present an optimization method for the reconstruction of a time signal from its Wigner distribution. The reconstruction technique enables a decomposition of a signal into its time-frequency components, where the reconstructed components are stripped off from the signal one by one. The method is illustrated a real data example. We also demonstrate how the decomposition can be used for suppression and enhancement of events in the time-frequency plane.
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    Time-frequency analysis of seismic sequences
    (1995-01-15) Steeghs, Philippe; Drijkoningen, Guy G; Digital Signal Processing (http://dsp.rice.edu/)
    Reflection patterns play an important role in seismic sequence stratigraphy, therefore making their quantitative description essential for the construction and validation of sequence stratigraphic models from seismic data. The characteristics of a seismic reflection pattern can be elicited from the data by representing the data as a joint function of time and frequency. Developments in the field of time-frequency analysis have led to t-f representations with better resolution than can be obtained with classical methods for local frequency analysis. This justifies a study of the application of these new representations to the analysis of seismic data. Some examples of the t-f representation of the seismic response of layered sequences are given. They clearly show the contribution of the stratigraphic sequence to the spectral content of the data. The construction of a sequence stratigraphic model from a t-f representation is demonstrated with a field data example where we match a pattern that was observed in the data to a sequence model.