Search results for "HTN"
showing 10 items of 252 documents
An adapted optical flow algorithm for robust quantification of cardiac wall motion from standard cine-MR examinations
2012
International audience; This paper presents a method for local myocardial motion estimation from a conventional steady-state free precession cine-MRI sequence using a modified phase-based optical flow (OF) technique. Initially, the technique was tested on synthetic images to evaluate its robustness with regards to Rician noise and to brightness variations. The method was then applied to cardiac images acquired on 11 healthy subjects. Myocardial velocity is measured in centimeter per second in each studied pixel and visualized as colored vectors superimposed on MRI images. The estimated phase-based OF results were compared with a reference OF method and gave similar results on synthetic imag…
Investigation of the skin lesions in lightning strike death
2021
Lightning strike-related deaths are unusual, and the victim bodies can present different lesions due to the different injury mechanisms associated with this event. Since the post mortem assessment can be challenging, the evaluation of the characteristics of the skin lesions becomes fundamental to reconstruct the event. Due to the paucity of literature on this topic, the authors report the case of a 59-year-old man found dead near his home after a thunderstorm. Initially considered a murder by gunshot, the autopsy revealed the typical lightning strike lesions, also known as Lichtenberg figures. The adequate interpretation of the autopsy data and the histological evidences allowed to reconstr…
The effect of an advertisement’s colour on emotions evoked by attitude towards the ad
2007
Despite its importance surprisingly little is known about the influence of colour in advertising. This paper studies the effects of the three components of an ad’s colour (hue, saturation and lightness) on the emotions it evokes and on attitudes towards it. It is assumed that the influence of colour varies with the individual, whose optimal stimulation level (OSL) is considered a moderator variable. Analyses of covariance were conducted. The results show that OSL is a moderator variable accounting for the relations between hue and the pleasure evoked by the ad, and hue and the attitude towards the ad. Moreover, OSL proves to be a moderator for the relation between saturation and the same de…
Improved Temperature and Emissivity Separation Algorithm for Multispectral and Hyperspectral Sensors
2017
The Temperature and Emissivity Separation (TES) algorithm was originally developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). This paper focuses on improving the TES algorithm. The main modification is the replacement of the normalized emissivity module with a new module, which is based on the smoothing of spectral radiance signatures. Smoothing is performed by estimating emissivity using an optimized approximation of the relationship between brightness temperature and emissivity. The improved TES algorithm, which is called Optimized Smoothing for Temperature Emissivity Separation (OSTES), was first tested on simulated data from three different sensors, …
First evaluation of the simultaneous SMOS and ELBARA-II observations in the Mediterranean region
2012
Abstract The SMOS (Soil Moisture and Ocean Salinity) mission was launched on November 2, 2009. Over the land surfaces, simultaneous retrievals of surface soil moisture (SM) and vegetation characteristics made from the multi-angular and dual polarization SMOS observations are now available from Level-2 (L2) products delivered by the European Space Agency (ESA). Therefore, first analyses evaluating the SMOS observations in terms of Brightness Temperatures (TB) and L2 products (SM and vegetation optical depth TAU) can be carried out over several calibration/validation (cal/val) sites selected by ESA over all continents. This study is based on SMOS observations and in situ measurements carried …
L-Band radiative properties of vine vegetation at the MELBEX III SMOS Cal/Val Site
2012
Radiative properties at 1.4 GHz of vine vegetation are investigated by measuring brightness temperatures with the ETH L-band Radiometer II (ELBARA II) operated on a tower at the Mediterranean Ecosystem L-band Characterisation Experiment III (MELBEX III) field site in Spain. To this aim, experiments with and without a reflecting foil placed under the vines were performed for the vegetation winter and summer states, respectively, to provide prevailingly information on vegetation transmissivities. The resulting parameters, which can be considered as "ground truth" for the MELBEX III vineyard, were retrieved from brightness temperature at horizontal and vertical polarization measured at observa…
Comparison of high‐speed optical observations of a lightning flash from space and the ground
2020
We analyze a nighttime negative cloud-to-ground lightning flash in Colombia observed from the ground with a high-speed camera at 5,000 images per second and from space by the Atmosphere-Space Interactions Monitor (ASIM) on the International Space Station (ISS), the Lightning Imaging Sensor also on the ISS (ISS-LIS), and the Geostationary Lightning Mapper (GLM) on GOES-16. The space instruments measure the oxygen band at 777.4 nm, allowing for direct comparisons of measurements, and the ground-based camera observes in a wide visible band. After conversion to energy emitted at the cloud top, we find a good linear correspondence of the optical energies measured by the three space instruments, …
Accuracy assessment of land surface temperature retrievals from MSG2-SEVIRI data
2011
The accuracy of the Land Surface Temperature (LST) product generated operationally by the EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) from the data registered by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the geostationary METEOSAT Second Generation 2 (MSG2, Meteosat 9) satellite was assessed on two test sites in Eastern Spain: a homogeneous, fully vegetated rice field and a high-plain, homogeneous area of shrubland. The LSA SAF LSTs were compared with ground LST measurements in the conventional temperature-based (T-based) method. We also validated the LSA SAF LST product by using an alternative radiance-based (R-based) method, with grou…
Examining the utility of pinhole-type screens for lightfield display
2021
The use of microlens arrays for lightfield display has the drawback of providing images with strong chromatic aliasing. To overcome this problem, pinhole-type lightfield monitors are proposed. This paper is devoted to evaluating the capability for such lightfield monitors to offer the user a convincing 3D experience with images with enough brightness and continuous aspect. Thus, we have designed a psychophysical test specifically adapted for lightfield monitors, which allowed us to confirm the usability of pinhole-type monitors.
The Modular X- and Gamma-Ray Sensor (MXGS)of the ASIM Payload on the International Space Station
2019
The Modular X- and Gamma-ray Sensor (MXGS) is an imaging and spectral X- and Gamma-ray instrument mounted on the starboard side of the Columbus module on the International Space Station. Together with the Modular Multi-Spectral Imaging Assembly (MMIA) (Chanrion et al. this issue) MXGS constitutes the instruments of the Atmosphere-Space Interactions Monitor (ASIM) (Neubert et al. this issue). The main objectives of MXGS are to image and measure the spectrum of X- and γ-rays from lightning discharges, known as Terrestrial Gamma-ray Flashes (TGFs), and for MMIA to image and perform high speed photometry of Transient Luminous Events (TLEs) and lightning discharges. With these two instruments sp…