Search results for "filtering"

Facepiece filtering respirators with exhalation valve should not be used in the community to limit SARS-CoV-2 diffusion.

2020

Isolation of the left atrial surface from cardiac multi-detector CT images based on marker controlled watershed segmentation

2006

The delineation of left atrium (LA) and pulmonary veins (PVs) anatomy from high resolution images holds importance for atrial fibrillation (AF) investigation and treatment. In this study, a semiautomatic segmentation procedure for LA and PVs inner surface from contrast enhanced CT data was developed. The procedure consists of a three dimensional marker controlled watershed segmentation applied to the external morphological gradient, followed by variable threshold surface extraction from the original intensity image. A preliminary anisotropic non-linear filtering was implemented to improve the S/N ratio of CT images. The performance of segmentation was evaluated on cardiac CT scans of 12 AF …

Intensity-invariant nonlinear filtering for detection in camouflage.

2005

We introduce a method based on an orthonormal vector space basis representation to detect camouflaged targets in natural environments. The method is intensity invariant so that camouflaged targets are detected independently of the illumination conditions. The detection technique does not require one to know the exact camouflage pattern, but only the class of patterns (e.g., foliage, netting, woods). We use nonlinear filtering and the calculation of several correlations. The nonlinearity of the filtering process also allows high discrimination against false targets. Several experiments confirm the target detectability where strong camouflage might delude even human viewers.

The data acquisition system for the ANTARES neutrino telescope

2006

The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described.

R-Score: A New Parameter to Assess the Quality of Variants’ Calls Assessed by NGS Using Liquid Biopsies

2021

Next-generation sequencing (NGS) has enabled a deeper knowledge of the molecular landscape in non-small cell lung cancer (NSCLC), identifying a growing number of targetable molecular alterations in key genes. However, NGS profiling of liquid biopsies risk for false positive and false negative calls and parameters assessing the quality of NGS calls remains lacking. In this study, we have evaluated the positive percent agreement (PPA) between NGS and digital PCR calls when assessing EGFR mutation status using 85 plasma samples from 82 EGFR-positive NSCLC patients. According to our data, variant allele fraction (VAF) was significantly lower in discordant calls and the median of the absolute va…

Programmable opticaldigital processor for rank order and morphological filtering

1995

A flexible hybrid opto-electronic processor for rank-order and morphological filtering is presented. The system is based on the shadow-casting convolver architecture, and the threshold decomposition concept. It provides the possibility of programming the input image and structuring element at video rate. The possibilities of the processor are experimentally demonstrated.

Digital estimators of relaxation spectra

2007

Determination of the distribution of relaxation times (DRT) from a wide variety of the time- and the frequency-domain material functions, such as polarization current and charge, real and imaginary parts of complex dielectric permittivity and complex dielectric modulus, the appropriate mechanical and magnetic counterparts is generalized as a filtering problem on a logarithmic time or frequency scale. Algorithms of the appropriate digital DRT estimators are derived. A novel regularization strategy is proposed based on choosing sampling rate for the input data, which ensures acceptably low random error of the recovered spectra. Optimum frequency ranges and sampling rates are found for determi…

Backbone of credit relationships in the Japanese credit market

2016

We detect the backbone of the weighted bipartite network of the Japanese credit market relationships. The backbone is detected by adapting a general method used in the investigation of weighted networks. With this approach we detect a backbone that is statistically validated against a null hypothesis of uniform diversification of loans for banks and firms. Our investigation is done year by year and it covers more than thirty years during the period from 1980 to 2011. We relate some of our findings with economic events that have characterized the Japanese credit market during the last years. The study of the time evolution of the backbone allows us to detect changes occurred in network size,…

Implementation and Performance of the Signal Reconstruction in the ATLAS Hadronic Tile Calorimeter

2012

AbstractThe Tile Calorimeter (TileCal) for the ATLAS experiment at the CERN Large Hadron Collider (LHC) is currently taking data with proton-proton collisions. The Tile Calorimeter is a sampling calorimeter with steel as absorber and scintillators as active medium. The scintillators are read-out by wavelength shifting fibers coupled to photomultiplier tubes (PMT). The analogue signals from the PMTs are amplified, shaped and digitized by sampling the signal every 25ns. The TileCal front-end electronics allows to read-out the signals produced by about 10000 channels measuring energies ranging from ∼30 MeV to ∼2 TeV. The read-out system is designed to reconstruct the data in real-time fulfilli…

Management and use of filter masks in the “none-medical” population during the Covid-19 period

2020

Abstract SARS-CoV-2 has become a pandemic disease declared by the World Health Organization, consequently each nation has taken a series of actions managed by the government in order to prevent the spread of this dangerous virus. The most common countermeasure is the use of a mask that should cover the mouth and nose to filter the inhaled and exhaled air. Those masks are medical devices that should be handled properly; unfortunately in our study, observation of the population during the so-called “phase 2″ has very often shown an inappropriate use of any type of mask which reduces its effectiveness. The correct dissemination of adequate information on how to use the mask and the strict cont…