Search results for " view"
showing 10 items of 337 documents
The on-board calibration system of the X-ray Imaging Polarimetry Explorer (XIPE)
2016
The calibration system for XIPE is aimed at providing a way to check and correct possible variations of performance of the Gas Pixel Detector during the three years of operation in orbit (plus two years of possible extended operation), while facilitating the observation of the celestial sources. This will be performed by using a filter wheel with a large heritage having a set of positions for the calibration and the observation systems. In particular, it will allow for correcting possible gain variation, for measuring the modulation factor using a polarized source, for removing non interesting bright sources in the field of view and for observing very bright celestial sources. The on-board …
Background Simulations of the Wide Field Imager of the ATHENA X-Ray Observatory
2011
The ATHENA X-ray Observatory-IXO is a planned multinational orbiting X-ray observatory with a focal length of 11.5m. ATHENA aims to perform pointed observations in an energy range from 0.1 keV to 15 keV with high sensitivity. For high spatial and timing resolution imaging and spectroscopic observations the 640x640 pixel^2 large DePFET-technology based Wide field Imager (WFI) focal plane detector, providing a field of view of 18 arcsec will be the main detector. Based on the actual mechanics, thermal and shielding design we present estimates for the WFI cosmic ray induced background obtained by the use of Monte-Carlo simulations and possible background reduction measures.
Three-dimensional display by smart pseudoscopic-to-orthoscopic conversion with tunable focus.
2014
The original aim of the integral-imaging concept, reported by Gabriel Lippmann more than a century ago, is the capture of images of 3D scenes for their projection onto an autostereoscopic display. In this paper we report a new algorithm for the efficient generation of microimages for their direct projection onto an integral-imaging monitor. Like our previous algorithm, the smart pseudoscopic-to-orthoscopic conversion (SPOC) algorithm, this algorithm produces microimages ready to produce 3D display with full parallax. However, this new algorithm is much simpler than the previous one, produces microimages free of black pixels, and permits fixing at will, between certain limits, the reference …
Wider is better but sharper is not: optimizing the image of camera-monitor systems
2021
The replacement of rear-view mirrors with camera-monitor systems introduces new opportunities for design, such as altering the image quality and the rearward field-of-view. We investigated how the image quality and field-of-view might affect the distance and time-to-contact estimation of other vehicles. Eighty-six subjects estimated either their egocentric distance to a stationary vehicle (Experiment I) or the time-to-contact to an approaching vehicle (Experiment II). Throughout the experiments, the pixel density and either the field-of-view or the viewing condition varied. A larger field-of-view increased distance estimation accuracy and confidence. Reduced pixel density led to larger esti…
Water‐vapour retrieval from Meteosat 8/SEVIRI observations
2007
This paper aims to propose operational algorithms to retrieve the total atmospheric water vapour content (W) using the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on-board Meteosat 8. MODTRAN3.5 was used to obtain simulated data in the thermal infrared channels IR10.8 and IR12.0, in order to determine the numerical values of the coefficients of the algorithms. The algorithm proposed for land pixels takes into account the SEVIRI observation geometry and the radiometric temperatures obtained in the split-window channels at two different times during a day and requires a minimum difference of 10 K in terms of temperature between the two situations. Comprehensive error analyses gave …
Influence of pixel size on quantification of airway wall thickness in computed tomography.
2009
Objectives: The purpose of this study was to determine the point where a further decrease in voxel size does not result in better automatic quantification of the bronchial wall thickness by using 2 different assessment techniques. Materials and Methods: The results from the commonly used full-width-at-half-maximum (FWHM) principle and a new technique (integral-based method [IBM]) were compared for thin-section multidetector computed tomography (MDCT) data sets from an airway phantom containing 10 different tubular airway phantoms and in a human subsegmental bronchus in vivo. Correlation with the actual wall thickness and comparison of the wall thicknesses assessed for different voxel sizes …
Se l’enunciatore non parla. Note sulla nozione ducrotiana di punto di vista.
2018
«Voice» and «Point of view» have been two of the most debated topics in some fields of linguistics and semiotics. Generally, DUCROT (1984) is considered like one of the first essays which introduced these concepts in the theoretical framework of the analysis of enunciation. As for the first one, the Author limits himself to suggest that it is connected with the notion of «discourse». In fact, by examining some topics of SPERBER & WILSON (1978), he seems to assimilate «voice» to «discourse». Indeed, you can read «j’ai substitué l’expression “faire entendre une voix” à leur expression “mentionner un discours”». As for the second concept, He seems to assimilate «point of view» to intuitive not…
Estilo y autoría en la información. Una aparente ausencia de identidad
2009
Dolors.Palau@uv.es Los textos periodísticos son un reflejo de los diversos estilos, de la diversidad de formas de ver y construir la realidad de los periodistas que los elaboran. Más allá de la prescripción y las posturas acríticas que han presidido la reflexión sobre estas cuestiones, este artículo aboga por un análisis que saque a la luz los mecanismos lingüísticos en los que se refleja el punto de vista, las estrategias que subyacen a una aparente ausencia de identidad, a una autoría pretendidamente enmascarada. Para ello parte de una revisión pluridisciplinar de los conceptos de estilo y autor, antes de proponer y aplicar un método de análisis pragmaestilístico. Journalistic articles ar…
Plagiarists by chance or by choice? Literature and film tell plagiarism
2019
The notion of plagiarism is so controversial and richly stratified that it fascinates scholars from many different disciplines. For the boundary between plagiarism and similar notions is rather hard to be established. Originality is threatened from any direction: consider imitation, copy, theft. Many forgers are around: some start from afar, some others simply seize the opportunity. Then fatally, the threshold between fiction and reality is trespassed: novels’ plots are about plagiarism, and also cinema easily takes that obsession over. There are plenty of stories that concern a literary theft. This set is so large that it justifies a more general question: how plagiarism can be told? This …
The INTEGRAL IBIS/ISGRI System Point Spread Function and Source Location Accuracy
2003
The imager on board INTEGRAL (IBIS) presently provides the most detailed sky images ever obtained at energies above 30 keV. The telescope is based on a coded aperture imaging system which allows to obtain sky images in a large field of view 29deg x 29deg with an angular resolution of 12'. The System Point Spread Function of the telescope and its detailed characteristics are here described along with the specific analysis algorithms used to derive the accurate point-like source locations. The derived location accuracy is studied using the first in-flight calibration data on strong sources for the IBIS/ISGRI system. The dependence of the calibrated location accuracy with the signal to noise r…