Influence Of Wavelet Research Articles

High-dimensional co-occurrence matrix: A new tool for 3D seismic target visualization and interpretation

The interpretation of seismic attributes has been developed for more than 40 years, but it still cannot be fully matched with the study of geologic sedimentology. There are two main bottlenecks. One is that almost no attributes can completely characterize amplitudes from a 3D perspective. Another is the influence of wavelets (frequency and phase). Accordingly, a new volumetric attribute extraction technique is presented for solving these two problems as much as possible. A high-dimensional co-occurrence matrix (HCM), as a statistical representation of the spatial structural relationship between data points, can be one of the solutions to extracting 3D attributes. By considering the global spatial distribution, the HCM fixes the directional distortion of the existing co-occurrence matrix methods and effectively suppresses vertical wavelet illusions. By realizing a rapid transformation of seismic data to 3D geologic target visualizations, this method does not rely heavily on structural information such as dip and azimuth and becomes a convenient bridge from seismic to geologic interpretation. We have applied the methodology to channel delineation in a 3D seismic survey acquired in Ordos, China. The results indicate that the attribute volume extracted from HCM expresses the geologic target convincingly and eliminates the illusions caused by the wavelets. The deposition history of the channels could be observed continuously through geologic time.

Magnetometer calibration improvement using wavelet and genetic algorithm

Three‐axis magnetometer error and measurement noise influence the accuracy of magnetic measurements. Genetic algorithm (GA) is proposed to calibrate the magnetometer error, and wavelet is proposed for noise cancellation. The noise of a Mag3300 magnetometer and a DM magnetometer were tested within a horizontal barrel shield equipment. Five kinds of wavelet analysis and two kinds of wavelet package were used for noise cancellation, and the performance of different wavelets was compared. Noise of the Mag3300 magnetometer and DM magnetometer were suppressed from 29.6 and 2.3466 to 3.7 and 1.0789 nT, respectively. The scalar error of the Mag3300 magnetometer was tested using a two‐dimensional nonmagnetic rotation equipment and a GSM‐19T proton magnetometer. Scalar calibration performances of the unscented Kalman filter (UKF), the two‐step algorithm, and GA were compared. Experimental results show that GA provides less error intensity (about 370 and 70 nT) than UKF and the two‐step algorithm. In addition, the influence of wavelet on scalar calibration using UKF, the two‐step algorithm, and GA was analyzed. Results show that wavelet improved the scalar calibration performance. Mean error of the Mag3300 magnetometer scalar was 795.5 nT. When combined with the wavelet package, the error was suppressed to −22.3, 3.3, and −0.4 nT using UKF, the two‐step algorithm, and GA, respectively. The results suggest an effective way for magnetometer calibration using GA and wavelet. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

The influence of wavelets on music research

Starting in the late 1980s, wavelets have been used for a variety of purposes in music research. The earliest and still most prevalent use of wavelets has been time–frequency representations of musical signals, as a superior alternative to Fourier analysis. Computer music specialists interested in sound synthesis have also used wavelets as a means of dynamic filtering and separating monaurally superimposed sounds. One researcher has explored the use of wavelets in detecting patterns of whole pitches or rhythms, with varied results. And researchers at Yale University have used wavelets for noise reduction of a 1889 recording of Johannes Brahms performing his Hungarian Dance Number 1. In this paper the different types of wavelet transforms used in the music research mentioned above are explained, and future uses in timber research and sound synthesis is explored.