A review of advances in pixel detectors for experiments with high rate and radiation

The Large Hadron Collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog. Phy

Manufacturing Metrology

Metrology is the science of measurement, which can be divided into three overlapping activities: (1) the definition of units of measurement, (2) the realization of units of measurement, and (3) the traceability of measurement units. Manufacturing metrology originally implicates the measurement of components and inputs for a manufacturing process to assure they are within specification requirements. It can also be extended to indicate the performance measurement of manufacturing equipment. This Special Issue covers papers revealing novel measurement methodologies and instrumentations for manufacturing metrology from the conventional industry to the frontier of the advanced hi-tech industry. Twenty-five papers are included in this Special Issue. These published papers can be categorized into four main groups, as follows: Length measurement: covering new designs, from micro/nanogap measurement with laser triangulation sensors and laser interferometers to very-long-distance, newly developed mode-locked femtosecond lasers. Surface profile and form measurements: covering technologies with new confocal sensors and imagine sensors: in situ and on-machine measurements. Angle measurements: these include a new 2D precision level design, a review of angle measurement with mode-locked femtosecond lasers, and multi-axis machine tool squareness measurement. Other laboratory systems: these include a water cooling temperature control system and a computer-aided inspection framework for CMM performance evaluation

Techniques and Technologies for Earth-twin Discoveries

In this Thesis I present and discuss the work completed during my three and a half years as a PhD student in the Exoplanet Research Group of the Cavendish Laboratory, University of Cambridge, UK. Most of my work has been in collaboration and partnership with the HARPS3 instrument and the Terra Hunting Experiment. My focus is on the development of new techniques and technologies that are aimed at aiding the discovery of an ‘Earth-twin’ exoplanet. In the context of this work, I use the term Earth-twin to mean an Earth-massed rocky planet orbiting a Sun-like star at a period of around 300 days. I created a pipeline prototype for fitting planetary models to radial velocity (RV) data. The data can contain any number of random or systematic noise sources, and can be poorly sampled. The analysis is conducted in a nested-sampling Bayesian framework and thus allows for the direct statistical comparison of different planetary models given some data set, and produces full posterior estimation for all the parameters of all the models. I used this analysis technique to test the feasibility of using intense ground-based RV surveys to detect Earth-twins, and to compare the results with typical survey cadences. I found that an intense survey reliably and regularly finds a variety of planets, including the Earth-twins, and out-performs the typical survey cadence. The major new technology I have developed is an experiment to measure the geometric positions of the pixels of an optical CCD, and the data analysis pipeline to compute the results. In exoplanet science, precise measurements of the Doppler shift of the stellar spectral lines enable us to confirm the presence of planets. However, at some level of precision, our uncertainty of the detector itself starts to inhibit our detection capability. Hence, if we are to be successful in the discovery of low mass planets, we require knowledge of the sub-pixel structure of our detector. I used the analysis scripts to help plan and design an optical experiment which was then built to analyse a large format optical detector and measure the positions of the pixels. I found the simulation of the experiment can measure the pixel positions to a precision of less than 0.001 pixels, but the experiment was plagued with thermal variations and ultimately was not capable of such precise measurements.STF

Design of LCOS microdisplay backplanes for projection applications

De evolutie van licht emitterende diodes (LED) heeft ervoor gezorgd dat het op dit moment interessant wordt om deze componenten als lichtbron te gebruiken in projectiesystemen. LED’s hebben belangrijke voordelen vergeleken met klassieke booglampen. Ze zijn compact, ze hebben een veel grotere levensduur en ogenblikkelijke schakeltijden, ze werken op lage spanningen, etc. LED’s zijn smalbandig en kunnen een groterekleurenbereik realiseren. Ze hebben momenteel echter een beperkte helderheid. Naast de lichtbron is het type van de lichtklep ook bepalend voor de kwaliteit van een projectiesysteem. Er bestaan verschillende lichtkleptechnologieën waaronder die van de reflectieve LCOS-panelen. Deze lichtkleppen kunnen zeer hoge resoluties hebben en wordenvaak gebruikt in kwalitatieve, professionele projectiesystemen. LED’s zijn echter totaal verschillend van booglampen. Ze hebben een andere vorm, package, stralingspatroon, aansturing, fysische en thermische eigenschappen, etc. Hoewel er een twintigtal optische architecturen bekend zijn voor reflectieve beeldschermen (met een booglamp als lichtbron), zijn ze niet geschikt voor LED-projectoren en moeten nieuwe optische architecturen en een elektronische aansturing ontwikkeld worden. In dit doctoraat werd er hieromtrent onderzoek gedaan. Er werd uiteindelijk een driekleurenprojector (R, G, B) met een efficiënt LED-belichtingssysteem gebouwd met twee LCOS-lichtkleppen. Deze LEDprojector heeft superieure eigenschappen (zeer lange levensduur, beeldkwaliteit, etc.) en een matige lichtopbrengst

Geomatics support to the metric documentation of the archaeological heritage. Tests and validations on the use of low-cost, rapid, image-based sensors and systems.

L'abstract è presente nell'allegato / the abstract is in the attachmen

Microoptical multi aperture imaging systems

Die Verkleinerung digitaler Einzelapertur-Abbildungssysteme erreicht aktuell physikalische sowie technische Limits. Die Miniaturisierung führt zu einer Verringerung sowohl des Auflösungsvermögens als auch des Signal-Rausch-Verhältnisses. Einen Ausweg zeigen die Prinzipien der kleinsten in der Natur bekannten Sehsysteme - die Facettenaugen. Die parallelisierte Anordnung einer großen Anzahl von Optiken ermöglicht, trotz der geringen Baugröße, eine große Informationsmenge aus einem ausgedehnten Gesichtsfeld zu übertragen. Ziel ist es, die Vorteile natürlicher Facettenaugen zu analysieren und diese zur Überwindung aktueller Grenzen der Miniaturisierung von digitalen Kameras zu adaptieren. Durch die Synergie von Optik, Opto-Elektronik und Bildverarbeitung wird die Miniaturisierung unter Erreichung praxisrelevanter Parameter angestrebt. Dafür wurde eine systematische Einteilung bereits bekannter und neuartiger Prinzipien von Multiapertur-Abbildungssystemen vorgenommen. Das grundlegende Verständnis der Vor- und Nachteile sowie des Skalierungsverhaltens der verschiedenen Ansätze ermöglichte die detaillierte Untersuchung der zwei erfolgversprechendsten Systemklassen. Für die Auslegung der Multiapertur-Optiken wurde eine Kombination aus Ansätzen des klassischen Optikdesigns und neuen semi-automatisierten Simulations- und Optimierungsmethoden mittels Ray-Tracing angewandt. Die mit natürlichen Facettenaugen vergleichbare Größe der Optiken ermöglichte die Verwendung mikrooptischer Herstellungsverfahren im Wafermaßstab. Es wurden Prototypen experimentell untersucht und die simulierten Systemparameter mit Hilfe der für die Multiapertur Anordnungen angepassten Messmethoden bestätigt. Die dargestellten Lösungen demonstrieren grundsätzlich neue Ansätze für den Bereich der hochauflösenden, miniaturisierten Abbildungsoptik, die kleinste Baulängen bei gegebenem Auflösungsvermögen erzielen. Somit sind sie im Stande die Skalierungslimits der Einzelapertur-Abbildungsoptik zu überwinden

Vision Sensors and Edge Detection

Vision Sensors and Edge Detection book reflects a selection of recent developments within the area of vision sensors and edge detection. There are two sections in this book. The first section presents vision sensors with applications to panoramic vision sensors, wireless vision sensors, and automated vision sensor inspection, and the second one shows image processing techniques, such as, image measurements, image transformations, filtering, and parallel computing

A gaussian process-based multi-sensor metrology system for precision measurement of freeform surfaces

Nowadays, precision freeform surfaces play an important role since they have superior performance and indispensable functionalities. Due to their geometrical complexity, high form accuracy and low surface roughness, precision freeform surfaces introduce a lot of research challenges in precision manufacturing and measurement processes. This is particularly true when the measurement is performed on traditional off-line single-sensor instruments such as white light interferometers (WLIs) and coordinate measuring machines (CMMs) whose measurement abilities are limited. For a single-sensor instrument, the measurement range and measurement resolution always need to strike a balance since the two terms appear to be contradictory. Moreover, when the workpiece is extremely large and error compensation procedure is needed to correct the form error of the workpiece, it is necessary to perform the measurement on machining facilities since repositioning error is unacceptable. However, off-line based measurement instruments cannot fulfil the in-situ measurement requirement. To address the above issues, this research firstly established a generic Gaussian process data modelling and image registration-based stitching method for the measurement of precision freeform surfaces based on traditional single-sensor surface measurement instruments using multiple measurement methods. With the proposed method, a dataset with a large measurement range and high resolution can be obtained. The proposed stitching method provides a turn-key solution for high dynamic range measurement using single-sensor instruments with a multiple measurement method. For multi-sensor instruments such as multi-sensor coordinate measuring machines (CMMs), this study proposes a Gaussian process-based data modelling and maximum likelihood data fusion method for the measurement of freeform surfaces for multi-sensor CMMs. The method utilizes an optical sensor such as laser sensor and a touch trigger probe mounted on the multi-sensor coordinate measuring machine for the measurement of freeform surfaces, and the measurement data are modelled using the Gaussian process modelling method. The combination of different kinds of sensors balances the measurement efficiency and accuracy since most optical sensors have a fast measurement speed and high density but low accuracy while contact sensors have an accurate measurement result but low efficiency. The measurement datasets from the laser sensor and touch trigger probe were fused with a maximum likelihood method so as to reduce the overall measurement uncertainty. To address the in-situ measurement issue, this thesis proposes an autonomous multi-sensor in-situ metrology system for high dynamic range measurement of freeform surfaces for precision machine tools. The system utilizes a laser scanner and a motion sensor together with a designed trajectory so as to perform in-situ measurement on the machining facilities. The proposed system is independent of the machining facilities which makes it extendable to a wide range of industrial applications. Based on the theory developed for the autonomous multi-sensor in-situ metrology system, a homogeneous multi-sensor in-situ measurement metrology system was developed equipped with a laser line sensor and laser point sensor. The laser line sensor provides high lateral resolution data while the laser point sensor gives accurate data. The measurement data from these two kinds of sensors are fused to obtain a more accurate result without losing the high lateral resolution. The present study has very large potential applications in industry. The successful development of the Gaussian process and image registration-based stitching method provides an important means for high dynamic range measurement, while the Gaussian process-based data modelling and maximum likelihood-based data fusion method establishes a generic measurement strategy for multi-sensor coordinate measuring machines so as to improve the measurement accuracy for precision freeform surfaces. The proposed in-situ multi-sensor high dynamic range measurement method and hence the homogeneous multi-sensor in-situ metrology system enable the measurement ability of machine tools so as to improve the efficiency and accuracy of the precision manufacture of complex freeform surfaces. The outcome of the research contributes significantly to the measurement science and technology, especially in the field of multi-sensor measurement and in-situ measurement of precision freeform surfaces

Algorithms for the enhancement of dynamic range and colour constancy of digital images & video

One of the main objectives in digital imaging is to mimic the capabilities of the human eye, and perhaps, go beyond in certain aspects. However, the human visual system is so versatile, complex, and only partially understood that no up-to-date imaging technology has been able to accurately reproduce the capabilities of the it. The extraordinary capabilities of the human eye have become a crucial shortcoming in digital imaging, since digital photography, video recording, and computer vision applications have continued to demand more realistic and accurate imaging reproduction and analytic capabilities. Over decades, researchers have tried to solve the colour constancy problem, as well as extending the dynamic range of digital imaging devices by proposing a number of algorithms and instrumentation approaches. Nevertheless, no unique solution has been identified; this is partially due to the wide range of computer vision applications that require colour constancy and high dynamic range imaging, and the complexity of the human visual system to achieve effective colour constancy and dynamic range capabilities. The aim of the research presented in this thesis is to enhance the overall image quality within an image signal processor of digital cameras by achieving colour constancy and extending dynamic range capabilities. This is achieved by developing a set of advanced image-processing algorithms that are robust to a number of practical challenges and feasible to be implemented within an image signal processor used in consumer electronics imaging devises. The experiments conducted in this research show that the proposed algorithms supersede state-of-the-art methods in the fields of dynamic range and colour constancy. Moreover, this unique set of image processing algorithms show that if they are used within an image signal processor, they enable digital camera devices to mimic the human visual system s dynamic range and colour constancy capabilities; the ultimate goal of any state-of-the-art technique, or commercial imaging device