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...

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 ...

We study the compression performance of the quincunx discrete wavelet transform (DWT) and we compare it with the dyadic DWT in terms of PSNR and bit rate. The 2D non-separable quincunx wavelet filters are designed by making use of the ‘transformations of variables’ technique of Tay & Kingsbury starting from the 1D biorthogonal (9,7)-taps filters. The applied transformation functions are respect...

A new lossless scalable coding based on a lossless wavelet transform (LWT) and a lossless multi-channel prediction (LMP) is proposed. A rough image can be expanded from a part of the bit stream for the use of progressive transmission. The LMP, a non-separable 2D filter bank, is optimized for an arbitrary input image signal so that remaining correlation of the band signals of the LWT can be util...

We present a method for using large, high dimension and high dynamic range datasets on modern graphics hardware. Datasets are preprocessed with a discrete wavelet transform, insignificant coefficients are removed, and the resulting compressed data is stored in standard 2D texture memory. A set of drop-in shader functions allows any shader program to sample the wavelet-encoded textures without a...

This paper addresses the problem of multiplicative jump detection and estimation in the time-scale plane. The signature is derived for a multiplicative jump in the time-scale plane. The signature allows the study of two wavelet based detectors. The first detector computes the Continuous Wavelet Transform (CWT) correlation with 2D signature. The second detector sums k e d scale slices of the CWT...

In this paper the damage in clamped-free, clampedclamped and free-free beam are analyzed considering samples without and with structural modifications. The damage location is investigated by the use of the bispectrum and wavelet analysis. The mathematical models are obtained using 2D elasticity theory and the Finite Element Method (FEM). The numerical and experimental data are approximated usin...