A main difference between Magnetic Resonance (MR) imaging and other medical imaging modalities is the control over the data acquisition and how it can be managed to finally show the adequate reconstructed image. With some basic programming adjustments, the user can modify the spatial resolution, field of view (FOV), image contrast, acquisition velocity, artifacts and so many other parameters th...

Synaptic efficacy can increase (synaptic facilitation) or decrease (synaptic depression) markedly within milliseconds after the onset of specific temporal patterns of activity. Recent evidence suggests that short-term synaptic depression contributes to low-pass temporal filtering, and can account for a well-known paradox - many low-pass neurons respond vigorously to transients and the onsets of...

Decimating a uniformly sampled signal a factor D involves low-pass antialias filtering with normalized cutoff frequency 1/D followed by picking out every Dth sample. Alternatively, decimation can be done in the frequency domain using the fast Fourier transform (FFT) algorithm, after zero-padding the signal and truncating the FFT. We outline three approaches to decimate nonuniformly sampled sign...

Natural open joints in rocks commonly present multi-scale self-affine apertures. This geometrical complexity affects fluid transport and heat exchange between the flowing fluid and the surrounding rock. In particular, long range correlations of self-affine apertures induce strong channeling of the flow which influences both mass and heat advection. A key question is to find a geometrical model ...

This work demonstrates the first measurements of blood flow velocity using photoacoustic flowmetry (PAF) employing a transducer array. The measurements were made in a flow phantom consisting of a tube (580 μm inner diameter) containing blood flowing steadily at physiological speeds ranging from 3 mm/s to 25 mm/s. Velocity measurements were based on the generation of two successive photoacoustic...

Introduction: Phase images of the brain generated using gradient echo sequences at high field strength show excellent contrast attributed to small field perturbations produced by susceptibility differences between tissues. In order to reveal the small phase variations related to the local anatomy it is however necessary to eliminate the large field offsets caused by remote tissue/air interfaces...

At present, the best way to render textured pointsampled 3D objects is doubtless the use of elliptical weighted average (EWA) surface splatting. This technique provides a high quality rendering of complex point models with anisotropic texture filtering. In this paper we present a new multi-pass approach to perform EWA surface splatting on modern PC graphics hardware. The main advantage of our a...

Evoked otoacoustic emissions (EOAEs) are currently used as the most reliable test for hearing screening. The presence of emission is commonly detected by the visual inspection of the signals and the cross-correlation function between replicate responses recorded in the same conditions. Performances of these methods are greatly influenced by the residual noise level. Residual noise is often of l...

The linear transform kernel for fractional Fourier transforms is derived. The spatial resolution and the space-bandwidth product for propagation in graded-index media are discussed in direct relation to fractional Fourier transforms, and numerical examples are presented. It is shown how fractional Fourier transforms can be made the basis of generalized spatial filtering systems: Several filters...

We demonstrate integrated, mode-evolution-based, 1x2 port high-pass/low-pass filters in a silicon photonics platform that can simultaneously achieve broadband operation, single cutoff wavelength, and a record high filter roll-off of 2.5 dB/nm for the first time. OCIS codes: (130.7408) Wavelength filtering devices; (230.1360) Beam splitters; (130.3120) Integrated optics devices.