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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Inteligentní kamera / An Intelligent camera system

Gogol, František January 2008 (has links)
An intelligent camera includes a processor, which can extract information from images without the need for an external processing unit, and interface devices used to make the results available to other devices. This paper describes the intelligent camera design and implementation into the Field Programmable Gate Array (FPGA). The implemented architecture contains a camera controller, a memory controller, an IIC controller, a VGA controller, and an execution unit. The camera controller communicates with a CMOS chip. The memory controller communicates with a DDR SDRAM memory. The IIC controller is the interface between a PLB bus and an IIC bus. The VGA controller takes data from the memory and transform them into the VGA format (640x480, 60 Hz). The execution unit extracts the image data from the memory. These data are processed by hardware pixel by pixel, which results in a modified image. The camera units has been implemented in the VHDL and Verilog languages.
2

Detector Development for the High Luminosity Large Hadron Collider

Rieger, Julia 02 August 2016 (has links)
Um das Entdeckungspotential des Large Hadron Colliders auszunutzen, wird er beginnend 2024 zum High Luminosity Large Hadron Collider ausgebaut. Neue Detektorherausforderungen entstehen durch die höhere instantane Luminosität und den höheren Teilchenfluss. Der neue ATLAS Inner Tracker wird den aktuellen Spurdetektor ersetzen, um mit diesen Herausforderungen umzugehen. Es gibt viele Pixeldetektortechnologien zur Teilchenspurerkennung, jedoch muss ihre Eignung für den ATLAS Inner Tracker untersucht werden. Aktive Hochspannungs-CMOS-Sensoren, die in industriellen Prozessen produziert werden, bieten eine schnelle Auslese und Strahlenhärte. In dieser Arbeit wird der HV2FEI4v2-Sensor, der kapazitiv mit dem ATLAS-FE-I4-Auslesechip gekoppelt ist, dahingehend charakterisiert, ob er für eine Verwendung in einer der äußeren Lagen des ATLAS Inner Tracker geeignet ist. Schlüsselgrößen des Prototypens, wie die Treffereffizienz und die Subpixelentschlüsselung, werden untersucht. Der frühe HV2FEI4v2-Prototyp zeigt vielversprechende Ergebnisse, die als Ausgangspunkt für weitere Entwicklungen dienen. Aktive CMOS-Sensoren stellen einen möglichen Kandidaten für einen kosteneffizienten Detektor für den High Luminosity Large Hadron Collider.
3

Un spectromètre à pixels actifs pour la métrologie des champs neutroniques / A spectrometer using active pixels sensors for the metrology of neutron fields

Taforeau, Julien 30 September 2013 (has links)
La métrologie fondamentale est la garante de la pérennité des systèmes de mesure et est en charge de fournir les étalons de références. En ce qui concerne la métrologie des rayonnements ionisants et, en particulier la métrologie des neutrons, des détecteurs étalons sont utilisés pour caractériser les champs de références, en énergie et en fluence. Les dosimètres ou détecteurs de particules sont étalonnés. Cette thèse présente le développement d’un spectromètre neutron candidat au statut d’étalon primaire pour la caractérisation de champs neutroniques dans la gamme 5-20 MeV. Le spectromètre utilise le principe du télescope à protons de recul comme moyen de détection ; la technologie CMOS, au travers de trois capteurs de positions, est mise à profit pour réaliser la trajectographie du proton de recul. Un détecteur Si(Li) est en charge de la mesure de l’énergie résiduelle du proton. Les simulations des dispositifs, réalisées sous MCNPX, ont permis d’estimer les performances du dispositif et de valider la procédure de reconstruction de l’énergie des champs neutroniques. Une étape essentielle de caractérisation des éléments du télescope et en particulier des capteurs CMOS est également proposée afin de garantir la validité de mesures expérimentales postérieures. Les tests réalisés aussi bien en champs mono-énergétiques qu’en champs étendus témoignent des très bonnes performances du système. La quantification des incertitudes indiquent une mesure de l’énergie avec une précision de plus de 1.5 % pour une résolution de moins de 6 %. La mesure de la fluence neutronique est quand a elle réalisée avec une incertitude de 4 à 6 %. / The fundamental metrology is responsible for the sustainability of the measurement systems and handles to supply the reference standards. Concerning the metrology of ionizing radiations and, in particular the neutron metrology, detectors standards are used to characterize reference fields, in terms of energy and fluence. The dosimeters or particle detectors are calibrated on these reference fields. This thesis presents the development of a neutron spectrometer neutron candidate to the status of primary standard for the characterization of neutron fields in the range from 5 to 20 MeV. The spectrometer uses the recoil proton telescope as detection principle; the CMOS technology, through three sensor positions, is taking advantage to realize the tracking of protons. A Si(Li) detector handles the measure of the residual proton energy. The device simulations, realized under MCNPX, allow to estimate its performances and to validate the neutron energy reconstruction. An essential step of characterization of the telescope elements and in particular of CMOS sensors is also proposed to guarantee the validity of posterior experimental measurements. The tests realized as well in mono-energy fields as in radionuclide source show the very good performances of the system. The quantification of uncertainties indicates an energy estimation with 1.5 % accuracy and a resolution of less than 6 %. The fluence measurement is performed with an uncertainty about 4 to 6%.
4

Novel developments in time-of-flight particle imaging

Lee, Jason W. L. January 2016 (has links)
In the field of physical chemistry, the relatively recently developed technique of velocity-map imaging has allowed chemical dynamics to be explored with a greater depth than could be previously achieved using other methods. Capturing the scattering image associated with the products resulting from fragmentation of a molecule allows the dissociative pathways and energy landscape to be investigated. In the study of particle physics, the neutron has become an irreplaceable spectroscopic tool due to the unique nature of the interaction with certain materials. Neutron spectroscopy is a non-destructive imaging technique that allows a number of properties to be discerned, including chemical identification, strain tensor measurements and the identification of beneath the sample surface using radiography and tomography. In both of these areas, as well as a multitude of other disciplines, a flight tube is used to separate particles, distinguishing them based upon their mass in the former case and their energy in the latter. The experiments can be vastly enhanced by the ability to record both the position and arrival time of the particle of interest. This thesis describes several new developments made in instrumentation for experiments involving time-of-flight particle imaging. The first development described is the construction of a new velocity-map imaging instrument that utilises electron ionisation to perform both steps of molecular fragmentation and ionisation. Data from CO2 is presented as an example of the ability of the instrument, and a preliminary analysis of the images is performed. The second presented project is the design of a time-resolved and position-resolved detector developed for ion imaging experiments. The hardware, software and firmware are described and presented alongside data from a variety of the experiments showcasing the breadth of investigations that are possible using the sensor. Finally, the modifications made to the detector to allow time-resolved neutron imaging are detailed, with an in-depth description of the various proof-of-concept experiments carried out as part of the development process.
5

<b>INTEGRATED LOW-FREQUESNCY AND HIGH FREQUENCY SENSORS FOR SINGLE-CELL DETECTION</b>

Abdulrahman Nasser a Alghamdi (17537103) 03 December 2023 (has links)
<p dir="ltr">Cell polarity as defined by biologists is the cell ability to sense, determine its direction and orient itself in specific direction (e.g., front and back, top and bottom, and inside and outside). Recent studies have shown that loss of cell polarity at the tissue-level is a signature of a tumor. Detecting tumor cells based on their polarization, i.e., their electrical permittivity at the single-cell level could open the door for potential new diagnosing tools. Developing sensitive tools that are affordable and can perform fast reading is an after-sought goal. Currently, biochemical techniques are the adapted methods for research and analysis. These techniques include fluorescence-based, affinity-based, electrochemistry-based, and optical-based methods. The main disadvantages of these methods are their bulky size, and high cost due to the use of the complex pre-labeling and cannot handle small numbers of cells. On the other hand, biophysical sensing techniques for single cell focus on the whole cell intrinsic properties such as molecular compositions, volume, mass, electrical properties (i.e., conductivity and permittivity), mechanical properties. Biophysical sensing based on electrical methods would be non-invasive, fast, safe for the cells, and affordable. </p><p dir="ltr">In this thesis, novel sensors for single-cell detection are presented. Design, simulation, fabrication, and in some cases, experimental characterization of these proposed microfluidic sensors are discussed in details. The use of low and high frequency readouts for cell detection as well as the long-term goal of integration as a CMOS sensing platform are demonstrated. Detection and counting of air-bubbles on mm-sized RF ring resonator are demonstrated as a first proof of concept. Miniaturized RF ring resonator and co-planar-waveguide (CPW) devices that are integrated with microfluidic channels to characterize single-cells are then discussed. Furthermore, a novel CMOS capacitor sensor for cell detection is proposed for the first time. The idea of the proposed sensor is based on a perforated MIM capacitor that allows the detection of cells by a change in the dielectric constant of the capacitor perforated with a micro-channel.</p>
6

Simplified fixed pattern noise correction and image display for high dynamic range CMOS logarithmic imagers

Otim, Stephen O. January 2007 (has links)
Biologically inspired logarithmic CMOS sensors offer high dynamic range imaging capabilities without the difficulties faced by linear imagers. By compressing dynamic range while encoding contrast information, they mimic the human visual system’s response to photo stimuli in fewer bits than those used in linear sensors. Despite this prospect, logarithmic sensors suffer poor image quality due to illumination dependent fixed pattern noise (FPN), making individual pixels appear up to 100 times brighter or darker. This thesis is primarily concerned with alleviating FPN in logarithmic imagers in a simple and convenient way while undertaking a system approach to its origin, distribution and effect on the quality of monochrome and colour images, after FPN correction. Using the properties of the Human visual system, I propose to characterise the errors arising from FPN in a perceptually significant manner by proposing an error measure, never used before. Logarithmic operation over a wide dynamic range is first characterised using a new model; yi j =aj +bj ln(exp sqrt(cj +djxi)−1), where yi j is the response of the sensor to a light stimulus xi and aj, bj, cj and dj are pixel dependent parameters. Using a proposed correction procedure, pixel data from a monochromatic sensor array is FPN corrected to approximately 4% error over 5 decades of illumination even after digitisation - accuracy equivalent to four times the human eyes ability to just notice an illumination difference against a uniform background. By evaluating how error affects colour, the possibility of indiscernible residual colour error after FPN correction, is analytically explored using a standard set of munsell colours. After simulating the simple FPN correction procedure, colour quality is analysed using a Delta E76 perceptual metric, to check for perceptual discrepancies in image colour. It is shown that, after quantisation, the FPN correction process yields 1−2 Delta E76 error units over approximately 5 decades of illumination; colour quality being imperceptibly uniform in this range. Finally, tone-mapping techniques, required to compress high dynamic range images onto the low range of standard screens, have a predominantly logarithmic operation during brightness compression. A new Logr'Gb' colour representation is presented in this thesis, significantly reducing computational complexity, while encoding contrast information. Using a well-known tone mapping technique, images represented in this new format are shown to maintain colour accuracy when the green colour channel is compressed to the standard display range, instead of the traditional luminance channel. The trade off between colour accuracy and computation in this tone mapping approach is also demonstrated, offering a low cost alternative for applications with low display specifications.
7

Development of CMOS sensors for a future neutron eleetronie personal dosemeter / Développement d'un capteur CMOS intégré pour un futur dosimètre électronique personnel de neutrons

Zhang, Ying 19 September 2012 (has links)
La thèse présente le développement de capteurs CMOS pour un futur dosimètre électronique neutrons. A côté des systèmes passifs largement répandus, les dosimètres actifs existants ne donnent pas satisfaction, alors qu’ils sont fermement recommandés par une directive européenne (IEC 1323). Le groupe RaMsEs de l’IPHC développe un nouveau concept de dosimètre électronique personnel neutrons à base de capteurs CMOS. Au cours de cette thèse, le circuit intégré AlphaRad2, à très bas bruit et très faible consommation électrique, a été implémenté dans une technologie commerciale. Il intègre un réseau de micro-diodes sur une surface sensible de 6.55 cm2 avec sa chaîne de traitement sur le même substrat de silicium. Des simulations physiques ont permis d’étudier le processus de collection de charge et d’optimiser l'efficacité de collection. La géométrie du capteur est un compromis entre la collection des électrons secondaires et de la capacité totale du détecteur. Le circuit de lecture comprend un amplificateur de charge (CSA), un circuit de mise en forme (shaper) et un discriminateur pour une réponse digitale. Nous présentons une analyse théorique complète du circuit, les paramètres de dessin, ainsi que des tests électriques et des tests en sources de rayonnement. La sensibilité effective du système est au niveau de la particule unique (proton ou alpha), grâce à un très bon rapport signal à bruit. Une série complète de mesures en sources de photons, de neutrons et de particules chargées a permis de démontrer une bonne efficacité aux neutrons rapides et surtout une excellente réjection gamma grâce à l’application d’un seuil électronique approprié. / This thesis presents the development of CMOS sensors for a future neutron sensitive electronic individual dosemeter. Active dosemeters, exist but do not yet give results as satisfactory as passive devices, being however, mandatory for workers in addition to the passive dosimetry since 1995 (IEC 1323). The RaMsEs group in the laboratory IPHC is exploring a new compact device based on CMOS sensors for operational neutron dosimetry. In this thesis, a dedicated sensor, AlphaRad-2, with low noise and very low power consumption (314 μW), has been implemented in a commercial CMOS technology. The AlphaRad-2 integrates the sensing part made of a micro-diode array of 32×32 n-well/p-epi diodes on a sensitive area of 6.55 mm2 and the signal processing electronics on the same silicon substrate. Device physics simulations have been performed to study the charge collection mechanism in diode matrices, and to optimize the collection efficiency and its time properties. The sensor geometry is a compromise between the collection performance and the total capacitance of the detector. A charge sensitive amplifier (CSA), a shaper, and a discriminator are employed in the readout circuit. We present its theoretical analysis, circuit design, and electrical tests. Our device has a sensitivity at the level of one single secondary charge particle (proton or α) thanks to its excellent noise performance. Extensive measurements to radioactive sources of α-particles, photons, and fast neutrons, have demonstrated good detection efficiency to fast neutrons and excellent γ-rejection through applying an appropriate electronic threshold.
8

Study of the time-dependent CP asymmetry in D° decays in the Belle II experiment / Etude de l'asymétrie de CP en fonction du temps dans les désintegrations du méson D° dans l'expérience Belle II

Maria, Robert Daniel 30 October 2015 (has links)
Nous étudions la sensibilité de Belle II avec 50 ab-1 de données sur l'angle βc du triangle d'unitarité, avec une mesure en fonction du temps de l'asymétrie de CP dans les désintégrations des mésons D0. Nous montrons que cette mesure est limitée statistiquement, avec une incertitude totale attendue de l'ordre de 3°. La mesure de βc nécessite la reconstruction de trajectoires de particules de très faible impulsion, impactée par le bruit de fond induit par SuperKEKB. Deux échelles PLUME vont être utilisées pour étudier ce bruit de fond. Ici, une étude des performances de PLUME est effectuée. Ainsi, la résolution spatiale avec des traces à 0° et 36° est mesurée, de 1,8 µm et 3,5µm respectivement. Par ailleurs nous proposons d'améliorer la mesure des faibles impulsions en utilisant la charge déposée par la particule dans le trajectomètre interne au silicium. L'estimateur permet d'améliorer par 2% la résolution sur l'impulsion pour les particules n'atteignant pas le trajectomètre interne. / We are studying the sensitivity of Belle II with 50 ab-1 data to the βc angle of the c-u unitarity triangle, with a time-dependent measurement of the CP asymmetry in the D0 decays. We show that such a measurement is still statistically limited, with a total expected incertitude of 3°.This measurement relies on the reconstruction of soft momenta, impacted by the SuperKEKB induced background.Two PLUME ladders will be used to study this background, therefore a study on the performances of PLUME was performed. The spatial resolution is of 1.8 µm and 3.5 µm for 0° and 36° tilted tracks respectivelly.We also propose to improve the estimation of soft momenta using the energy depositions of charged particles in the silicon layers of the inner tracker. Our estimator improves by approximately 2 % the resolution on momentum for particles which do not penetrate the central tracking system.

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