Nonparametric algorithm for the instantaneous frequency (IF) estimation, by using the Wigner distribution (WD) with an adaptive window length, is considered in the paper. This algorithm produces a bias-to-variance trade-o7 close to optimal, meaning almost minimal mean squared error (MSE) of the estimation. Thus, the adaptive window length is characterized by a small bias at the considered insta...

Computing global illumination in complex scenes is even with todays computational power a demanding task. In this work we propose a novel irradiance caching scheme that combines the advantages of two state-of-the-art algorithms for high-quality global illumination rendering: lightcuts, an adaptive and hierarchical instant-radiosity based algorithm and the widely used (ir)radiance caching algori...

X. Ma, S. M. LaConte, Y. M. Kadah, D. H. Frakes, A. P. Yoganathan, X. Hu Biomedical Engineering, Emory University/Georgia Tech, Atlanta, Georgia, United States, 4-D Imaging, Inc., Atlanta, Georgia, United States Introduction DTI is a useful tool for studying neuronal fiber structures of the human brain in vivo. However, the physical limitations on resolution and voxel size when using EPI-based ...

The problem of oscillatory polynomial interpolants arising from equally spaced mesh points is considered. It is shown that by making use of adaptive approaches that the oscillations may be contained and that the resulting polynomials are data bounded and monotone on each interval. This is achieved at the cost of using a different polynomial on each sub-interval. Computational results for a numb...

A novel tensor interpolation method is introduced that allows Diffusion Tensor Imaging (DTI) streamlining to overcome low-anisotropy regions and permits branching of trajectories using information gathered from the neighbourhood of low-anisotropy voxels met during the tracking. The interpolation method is performed in Log-Euclidean space and collects directional information in a spherical neigh...

A new seismic trace interpolation method based on adaptive prediction filters (PF) is introduced. In order to estimate local PFs, the contribution of adjacent windows of data to the process of local PF estimation is reduced via the introduction of a forgetting factor. Using a Recursive Least Square (RLS) algorithm, the problem of estimating PFs for each window of data is avoided and the local P...

Progressive image transmission is a mechanism that transmits the most significant portion of an image, followed by its less important parts. Applications of such a mechanism include browsing large image files on the Internet. We propose an adaptive mechanism, based on the characteristics of images. The mechanism use neighbor pixels to guess a target pixel value, without actually transmitting th...

The analysis of transient signals is an attractive framework for many problems in digital signal processing. This paper provides an application of the data adaptive linear decomposition transform (LDT) to detect transients in the sinusoidal signal corrupted by an additive impulse noise. The LDT procedure entails obtaining an interpolation error sequence of half-length of the sinusoidal signal, ...

In Magnetic Resonance Imaging, image resolution is limited by several factors such as hardware or time constraints. In many cases, the acquired images have to be upsampled to match a specific resolution. In such cases, image interpolation techniques have been traditionally applied. However, traditional interpolation techniques are not able to recover high frequency information of the underlying...

The aim of this paper is to present results on finite element adaptive strategies for computational fluid dynamics problems with singularities arising from shock phenomena and/or discontinuous boundary data. The adaptive analysis is based on an optimalmesh-adaptive strategy which is employed to refine the mesh, stretch and orient the elements in such a way that, along the adaptation process, th...