نتایج جستجو برای: 3d wavelet transform
تعداد نتایج: 320659 فیلتر نتایج به سال:
We summarise the construction of exact axisymmetric scalediscretised wavelets on the sphere and on the ball. The wavelet transform on the ball relies on a novel 3D harmonic transform called the Fourier-Laguerre transform which combines the spherical harmonic transform with damped Laguerre polynomials on the radial half-line. The resulting wavelets, called flaglets, extract scale-dependent, spat...
The aim of this paper is to examine a set of wavelet functions (wavelets) used in image watermarking system. Several wavelet functions are used to transform the component detail of the image in frequency domain. Discrete wavelet transform (DWT), discrete Fourier transform (DFT) and discrete cosine transform (DCT) are some commonly used transform domain functions out of which discrete wavelet tr...
introduction: an efficient method of tomographic imaging in nuclear medicine is positron emission tomography (pet). compared to spect, pet has the advantages of higher levels of sensitivity, spatial resolution and more accurate quantification. however, high noise levels in the image limit its diagnostic utility. noise removal in nuclear medicine is traditionally based on fourier decomposition o...
there are two methods for identifying formation interface in oil wells: core analysis, which is a precise approach but costly and time consuming, and well logs analysis, which petrophysists perform, which is subjective and not completely reliable. in this paper, a novel coupled method was proposed to detect the formation interfaces using gr logs. second approximation level (a2) of gr log gained...
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introduction: spect is a diagnostic imaging technique the main disadvantage of which is the existence of poisson noise. so far, different methods have been used by scientists to improve spect images. the wavelet transform is a new method for de-noising which is widely used for noise reduction and quality enhancement of images. the purpose of this paper is evaluation of noise reduction in spect ...
Mutual information is a widely-used metric in medical image registration, which achieves good results; however it can lead to misregistration because of the absence of spatial information. One of the works to overcome this problem is proposed by [10] in which a gradient-based term is combined with mutual information. In this paper, we improve the method in [10] and propose a registration strate...
Title: Abstract: I will discuss a new decomposition of the 3D X-ray transform based on the shearlet representation, a multiscale directional representation which is optimally efficient in handling 3D data containing edge singularities. This decomposition yields a highly effective reconstruction algorithm providing a near-optimal rate of convergence in estimating piecewise smooth objects from 3D...
A wide-spread use of 3D models in cultural heritage application requires low cost equipment and simple modeling procedures. In this context, passive 3D reconstruction methods allow to build 3D models from a set of calibrated cameras, without the need of expensive machinery. Unfortunately the surfaces characteristics often lead to bad quality reconstructions. Recent efforts attempt to combine to...
in exploration seismology quality factor is widely used as a seismic attribute to identify anomalies related to attenuation, especially those caused by hydrocarbon. previous studies have indicated that seismic energy loss known as attenuation is greater for high frequency components of seismic data compared to the low frequency components. here the continuous wavelet transform is used to study ...
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