BACKGROUND AND PURPOSE CTA is considered the imaging modality of choice in evaluating the supraaortic vessels in many institutions, but radiation exposure remains a matter of concern. The objective of the study was to evaluate a fully automated, attenuation-based kilovolt selection algorithm in carotid CTA in respect to radiation dose and image quality compared with a standard 120-kV protocol. ...

A new denoising approach is introduced in this paper. It is based on the fact that denoising may be performed by mimicking the human ear function in order to improve the psychoacoustics appearance of speech signal. In the proposed method, the speech signal is decomposed by using a gammatone filterbank in accordance with ERB scale. Spectral attenuation filtering is then applied in each sub-band ...

ELECT The specific differential attenuation caused by large raindrops and a special form of melting hail is computed and studied. Raindrops of smoothed conical shapes and hailstones modelled by an ice sphere surrounded by a water torus are considered. For the former, scattering computation is carried out by the T-matrix method, while the higherorder method of moments in the surface integral equ...

This paper proposes a novel dust-storm total path attenuation prediction model. model is formulated as function of specific (dB/km) and the effective distance, which considers non-uniform dust storm intensity variations throughout link. The distance obtained combination link reduction factor. factor developed based on modeled 2-D structure observed characteristics. A measurement campaign atmosp...

remotely sensed imagery is proving to be a useful tool to estimate water depths in coastalzones. bathymetric algorithms attempt to isolate water attenuation and hence depth from other factors byusing different combinations of spectral bands. in this research, images of absolute bathymetry using twodifferent but related methods in a region in the southern caspian sea coasts has been produced. th...

It is useful to have the ability to analyze the propagation of errors from transmission data into the resulting attenuation-corrected PET reconstruction. We develop theoretical expressions for the mean and covariance of the emission reconstruction when the only noise source is that in the transmission data. There are several ways to impose an attenuation correction onto the PET reconstructions,...

ABSTRACT Since its deployment at the surface of Mars, Seismic Experiment for Interior Structure (SEIS) instrument InSight mission has detected hundreds small-magnitude seismic events. In this work, we highlight some features two specific families: high-frequency (HF) and very-high-frequency (VF) We characterize shape energy envelopes HF VF events with parameters: (1) delay time td between onset...

Full waveform inversion (FWI) is a nonlinear PDE constrained optimization problem, which seeks to estimate constitutive parameters of medium such as phase velocity, density, and anisotropy, by fitting waveforms. Attenuation an additional parameter that needs be taken into account in viscous media exploit the full potential FWI. more easily implemented frequency domain using complex-valued veloc...

We develop non-linear optimization algorithms for attenuation compensation of rapidly time-varying microwave signals in the context breast imaging. The tissues attenuate energy scattered wavefield as it travels within medium. Compensating effect is a challenging and typically unstable task. To address this issue, we inversion-based that take advantage prior knowledge about system. formulate reg...