Search results for "ADAR"
showing 10 items of 781 documents
C# un C++ starp-valodu izsaukumi – pieejas un risinājumi
2018
Mūsdienās savstarpējā valodu sadarbspēja ir aktuāls temats, jo netriviālas programmatūras risinājumu izstrādē visbiežāk tiek izmantota vairāk kā viena programmēšanas valoda. Tomēr sadarbspējas ieviešanai nav viennozīmīgas pieejas, tādēļ autors darbā apskata pieejamo informāciju par eksistējošām valodu pāra C# un C++ sadarbspējas metodēm. Bakalaura darbā autors analizē un salīdzina divas .NET Framework platformas iedzimti nodrošinātās sadarbspējas pieejas - platformas izsaukšanu un C++ Interop metodi-, kā metodes C# starp-valodu izsaukumiem uz C++ kodu. Šo pieeju novērtēšanai tika izmantoti tādi kritēriji kā izmaksas, caurlaidspēja, darbietilpība un uzturamība. Autors veica mērījumus un apko…
Multispectral integral imaging acquisition and processing using a monochrome camera and a liquid crystal tunable filter
2012
This paper presents an acquisition system and a procedure to capture 3D scenes in different spectral bands. The acquisition system is formed by a monochrome camera, and a Liquid Crystal Tunable Filter (LCTF) that allows to acquire images at different spectral bands in the [480, 680]nm wavelength interval. The Synthetic Aperture Integral Imaging acquisition technique is used to obtain the elemental images for each wavelength. These elemental images are used to computationally obtain the reconstruction planes of the 3D scene at different depth planes. The 3D profile of the acquired scene is also obtained using a minimization of the variance of the contribution of the elemental images at each …
Quaderno di Diagnostica. Le indagini diagnostiche nel restauro dei monumenti
2010
Negli ultimi anni il crescente interesse per il costruito urbano e la maturazione di una sensibilità maggiore nei confronti dell'autenticità materiale delle architetture hanno supportato lo sviluppo dell'imponente settore sperimentale della diagnostica, che comprende le indagini preliminari, quelle in corso d'opera (diagnostica interventistica) e le verifiche della qualità degli interventi svolti. Lo sviluppo delle metodologie analitiche diagnostiche, in particolare delle scienze fisiche, chimiche, geognostiche e dei metodi informatici di calcolo, offre oggi ai restauratori una ricca serie di strumenti di previsione, di progettazione dei trattamenti da trasporre nella prassi operativa e di …
Superresolved Holographic Microscopy
2008
Superresolution methods in digital holographic microscopy provide a useful tool to overcome the Abbe's diffraction limit when using modest microscope lenses. The process improves the cutoff frequency of the microscope lens by means of the generation of a synthetic aperture based on time multiplexing and using 3 main stages: optical coding, optical decoding, and digital postprocessing. After the whole process, a superresolved image is obtained by Fourier transformation of the synthetic aperture.
Superesolution in digital holographic microscopy
2011
In this contribution, we address with the possibility to overcome the limited resolving power of imaging systems beyond the limit imposed by Abbe's diffraction theory. We first review the mathematical foundations underlying superresolution (SR) from an information theory point of view and then we focus on two multiplexing approaches in digital holographic microscopy (DHM) for achieving SR by synthetic aperture (SA) generation.
Synthetic Aperture Lensless Digital Holographic Microscopy (SALDHM) for Superresolved Biological Imaging
2013
Lensless digital holographic microscopy (LDHM) relates with the capability to achieve microscopic imaging working without lenses in the regime of holography. LDHM uses an extremely simplified setup and provides micron-range lateral and depth resolutions in three-dimensional (3D) imaging. Typically, LDHM uses a pinhole to provide spherical divergent illumination over the sample. Then, two different basic schemes are usually adopted for providing holographic recording. The first one assumes the interference between two in-line waves since diffraction by the sample can be considered as a perturbation of the reference wave. The second scheme uses an external reference beam in an off-line config…
Superresolved phase-shifting Gabor holography by CCD shift
2009
Holography in the Gabor regime is restricted to weak diffraction assumptions. Otherwise, diffraction prevents an accurate recovery of the object's complex wavefront. We have recently proposed a modified Gabor-like setup to extend Gabor's concept to any sample provided that it be non-diffusive. However, the resolution of the final image becomes limited as a consequence of the additional elements considered in the proposed setup. In this paper we present an experimental approach to overcome such a limitation in which the former configuration is used while the CCD camera is shifted to different off-axis positions in order to generate a synthetic aperture. Thus, once the whole image set is reco…
ETP/GDOP Behavior Study for N-Sensors Arrays ina Multilateration Radar System
2009
In this paper, we evaluated the ETP (Expected Theoretical Precision) and GDOP (Geometric Dilution Of Precision) enhancement related to the number of sensors in a Multilateration radar system. An introduction about the principles of the Multilateration radar system basis operation is described, then, the formulation for evaluation the ETP/GDOP of the 3D positioning is shown. We observed that the ETP and GDOP enhance with the increase of the number of sensors. A substantial improvement was obtained until nine sensors but, for more sensors that improvement is reduced. Results for a 75km×75km area are shown, including LAM (Local Area Multilateration) and WAM (Wide Area Multilateration) settings…
Non-Contact Measurement of River Surface Velocity and Discharge Estimation with a Low-Cost Doppler Radar Sensor
2020
River discharge is an important variable to measure in order to predict droughts and flood occurrences. Once the cross-sectional geometry of the river is known, discharge can be inferred from water level and surface flow velocity measurements. Since river discharges are of particular interest during extreme weather events, when river sites cannot be safely accessed, noncontact sensing technologies are particularly appealing. To this purpose, this work proposes a prototype of a low-cost continuous wave (CW) Doppler radar sensor, which is able to monitor the surface flow velocity of rivers. The prototype is tested at two gauged sites in central Italy, along the Tiber River. The surface flow v…
Using an X-band radar for an urban area early flood warning system
2021
Floods represent a serious hazard in many areas of the world in terms of damage to properties and loss of life. For this reason, the European Floods Directive 2007/60/EC on the assessment and management of flood risk required the relevant bodies of the Member States to have adequate and efficient tools for assessing the flood risk of river basins and establishing flood risk management plans focused on prevention and protection of territory and people. The decision makers involved in flood defense often need some hydro-informatics tools to transform the flood forecast into relatively simple and clear messages that allow them to take prompt action to prevent and/or counteract the flood. From …