Wyniki wyszukiwania - BazTech

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Resolution-oriented weighted stacking based on global optimization algorithm

Sun Yaoguang, Chen Siyuan, Cao Siyuan

Acta Geophysica

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2023

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Vol. 71, no. 5

2125--2135

EN

Stacking is one crucial seismic data processing technique that gives a composite record made by combining traces from different shot records. The quality of stacking dramatical affects the performance of many seismic data processing tasks. The conventional equal-weight stacking method is the average of all traces in the pre-stack CMP gather, improving the signal-to-noise ratio (SNR) but reducing resolution. Most weighted stacking algorithms aim to enhance image quality by the increased SNR; however, these algorithms do not consider the resolution. Therefore, we proposed a weighted stacking algorithm with resolution enhancement, which is regarded as having maximum bandwidth and dominant frequency. Based on the genetic algorithm (GA), we calculated the stacking weights in common midpoint (CMP), or common-reflection-point (CRP) gathers. Then, we presented a weighted stacking approach to obtain the resolution-enhancement stacked data. The proposed method can obtain the resolution-enhancement stacked data by the single-trace spectrum constraint without wavelet estimation. Applications to synthetic and field seismic datasets demonstrate that compared with the traditional stacking method, the proposed method can improve the stacking resolution better, which is beneficial for subsequent interpretation.

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An Efficient Edge Preserving Interpolation Method for Underwater Acoustic Image Resolution Enhancement

Priyadharsini R., Sree Sharmila T.

Archives of Acoustics

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2022

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Vol. 47, No. 2

267--274

EN

Underwater acoustic images are acquired using sonar instrument that uses sound propagation to navigate and map the sea floor. The sonar devices are effectively used to create images of large area of the seabed. However, the visual perception of the object in the acoustic image depends on refraction, which is a function of changes in the speed of sound in successive layers of water. And refraction depends mainly on temperature, slightly on salinity and hydrostatic pressure. The quality and resolution of sonar imaging of the bottom depends on many other factors such as pitch, yaw and heave of the side scan sonar, the presence of volume scatterers in the water body, the distance of the sonar from the bottom and orientation of the object. Generally, the objects in an acoustic image would be of small size compared to their normal size as the distance between the sonar and object is larger. To detect and recognize the objects in the images, the resolution should be enhanced. In this paper, we propose an efficient edge preserving interpolation method for underwater acoustic image resolution enhancement which preserves the edge sharpness. The method handles the diagonal pixels in the first pass, in turn fills the horizontal and vertical pixels in the second pass. The results obtained are compared with the state-of-the-art interpolation techniques and the performance measures such as Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index Measurement (SSIM) shows an improved result.

3

Integrated geophysical data for sweet spot identification in Baltic Basin, Poland

Cichostępski Kamil, Kwietniak Anna, Dec Jerzy, Kasperska Monika, Pietsch Kaja

Annales Societatis Geologorum Poloniae

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2019

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Vol. 89, No. 2

215--231

EN

In the paper, the authors present the results of seismic reservoir characterization of shale gas deposits of the Lower Silurian and Ordovician (Sasino Formation and Jantar Formation), which are localized within the onshore part of the Baltic Basin, N Poland. For this purpose, acoustic inversion of seismic data and petrophysical analysis of well-log data were incorporated. The new approach that the authors used for acoustic inversion was the resolution enhancement algorithm, known as spectral blueing, before proceeding with the acoustic inversion process. The spectral blueing procedure enhances the seismic spectrum by weighting it with the well reflectivity spectrum. The resulting enhanced seismic volume manifests itself in higher energies of the high frequency component, while keeping the frequency range constant. With the results of acoustic inversion after the spectral blueing procedure, the authors were able to define two more potential exploration sites within the Ordovician deposits.

4

Investigation of lime mortars and plasters from archaeological excavations in Hippos (Israel) using Electron Paramagnetic Resonance

Kabacińska Z., Krzyminiewski R., Michalska D., Dobosz B.

Geochronometria

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2014

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Vol. 41, no. 2

112--120

EN

This study presents the preliminary results of investigation of the lime mortars and plasters from archaeological excavations in Hippos (Israel), using Electron Paramagnetic Resonance (EPR) spectroscopy. The research was conducted in order to characterize the building material and its reaction to ionizing radiation. The ancient settlement Hippos, situated on the east shore of the Sea of Galilee, functioned from the 3rd cent. BC until it was destroyed by the earthquake in 749 AD. Lime mortars and plasters show carbonate and locally gypsum character of binder and different kind of aggregate. Samples were γ-irradiated and measured using X-band EPR spectrometer. Computer Resolution Enhancement Method was applied to the complex spectra. Some of the γ-induced EPR signals were attributed to CO 2 and CO 3 3- paramagnetic centres. Exponential growth of the dose response curve above 1 kGy and saturation for doses above 20 kGy was observed. For doses lower than 1 kGy the dose response curve has a linear character. The presence of γ-sensitive carbonate paramagnetic centres could indicate that, after further studies, well-chosen samples of mortars and plasters might be suitable for EPR dating, assuming the centres have been sufficiently bleached during the manufacturing process.