Evaluation of the color image and video processing chain and visual quality management for consumer systems

With the advent of novel digital display technologies, color processing is increasingly becoming a key aspect in consumer video applications. Today’s state-of-the-art displays require sophisticated color and image reproduction techniques in order to achieve larger screen size, higher luminance and higher resolution than ever before. However, from color science perspective, there are clearly opportunities for improvement in the color reproduction capabilities of various emerging and conventional display technologies. This research seeks to identify potential areas for improvement in color processing in a video processing chain. As part of this research, various processes involved in a typical video processing chain in consumer video applications were reviewed. Several published color and contrast enhancement algorithms were evaluated, and a novel algorithm was developed to enhance color and contrast in images and videos in an effective and coordinated manner. Further, a psychophysical technique was developed and implemented for performing visual evaluation of color image and consumer video quality. Based on the performance analysis and visual experiments involving various algorithms, guidelines were proposed for the development of an effective color and contrast enhancement method for images and video applications. It is hoped that the knowledge gained from this research will help build a better understanding of color processing and color quality management methods in consumer video

Iris Recognition: Robust Processing, Synthesis, Performance Evaluation and Applications

The popularity of iris biometric has grown considerably over the past few years. It has resulted in the development of a large number of new iris processing and encoding algorithms. In this dissertation, we will discuss the following aspects of the iris recognition problem: iris image acquisition, iris quality, iris segmentation, iris encoding, performance enhancement and two novel applications.;The specific claimed novelties of this dissertation include: (1) a method to generate a large scale realistic database of iris images; (2) a crosspectral iris matching method for comparison of images in color range against images in Near-Infrared (NIR) range; (3) a method to evaluate iris image and video quality; (4) a robust quality-based iris segmentation method; (5) several approaches to enhance recognition performance and security of traditional iris encoding techniques; (6) a method to increase iris capture volume for acquisition of iris on the move from a distance and (7) a method to improve performance of biometric systems due to available soft data in the form of links and connections in a relevant social network

Intelligent Side Information Generation in Distributed Video Coding

Distributed video coding (DVC) reverses the traditional coding paradigm of complex encoders allied with basic decoding to one where the computational cost is largely incurred by the decoder. This is attractive as the proven theoretical work of Wyner-Ziv (WZ) and Slepian-Wolf (SW) shows that the performance by such a system should be exactly the same as a conventional coder. Despite the solid theoretical foundations, current DVC qualitative and quantitative performance falls short of existing conventional coders and there remain crucial limitations. A key constraint governing DVC performance is the quality of side information (SI), a coarse representation of original video frames which are not available at the decoder. Techniques to generate SI have usually been based on linear motion compensated temporal interpolation (LMCTI), though these do not always produce satisfactory SI quality, especially in sequences exhibiting non-linear motion. This thesis presents an intelligent higher order piecewise trajectory temporal interpolation (HOPTTI) framework for SI generation with original contributions that afford better SI quality in comparison to existing LMCTI-based approaches. The major elements in this framework are: (i) a cubic trajectory interpolation algorithm model that significantly improves the accuracy of motion vector estimations; (ii) an adaptive overlapped block motion compensation (AOBMC) model which reduces both blocking and overlapping artefacts in the SI emanating from the block matching algorithm; (iii) the development of an empirical mode switching algorithm; and (iv) an intelligent switching mechanism to construct SI by automatically selecting the best macroblock from the intermediate SI generated by HOPTTI and AOBMC algorithms. Rigorous analysis and evaluation confirms that significant quantitative and perceptual improvements in SI quality are achieved with the new framework

Anomaly Detection, Rule Adaptation and Rule Induction Methodologies in the Context of Automated Sports Video Annotation.

Automated video annotation is a topic of considerable interest in computer vision due to its applications in video search, object based video encoding and enhanced broadcast content. The domain of sport broadcasting is, in particular, the subject of current research attention due to its fixed, rule governed, content. This research work aims to develop, analyze and demonstrate novel methodologies that can be useful in the context of adaptive and automated video annotation systems. In this thesis, we present methodologies for addressing the problems of anomaly detection, rule adaptation and rule induction for court based sports such as tennis and badminton. We first introduce an HMM induction strategy for a court-model based method that uses the court structure in the form of a lattice for two related modalities of singles and doubles tennis to tackle the problems of anomaly detection and rectification. We also introduce another anomaly detection methodology that is based on the disparity between the low-level vision based classifiers and the high-level contextual classifier. Another approach to address the problem of rule adaptation is also proposed that employs Convex hulling of the anomalous states. We also investigate a number of novel hierarchical HMM generating methods for stochastic induction of game rules. These methodologies include, Cartesian product Label-based Hierarchical Bottom-up Clustering (CLHBC) that employs prior information within the label structures. A new constrained variant of the classical Chinese Restaurant Process (CRP) is also introduced that is relevant to sports games. We also propose two hybrid methodologies in this context and a comparative analysis is made against the flat Markov model. We also show that these methods are also generalizable to other rule based environments

The structure and dynamics of multilayer networks

In the past years, network theory has successfully characterized the interaction among the constituents of a variety of complex systems, ranging from biological to technological, and social systems. However, up until recently, attention was almost exclusively given to networks in which all components were treated on equivalent footing, while neglecting all the extra information about the temporal- or context-related properties of the interactions under study. Only in the last years, taking advantage of the enhanced resolution in real data sets, network scientists have directed their interest to the multiplex character of real-world systems, and explicitly considered the time-varying and multilayer nature of networks. We offer here a comprehensive review on both structural and dynamical organization of graphs made of diverse relationships (layers) between its constituents, and cover several relevant issues, from a full redefinition of the basic structural measures, to understanding how the multilayer nature of the network affects processes and dynamics.Comment: In Press, Accepted Manuscript, Physics Reports 201

Multiscale modelling of woven and knitted fabric membranes

Light-weight fabric membranes have gained increasing popularity over the past years due to their tailorable structural and material performances. These tailorable properties include stretch forming and deep drawing formability that exhibits excellent stretchability and drapeability properties of textiles and textile composites. Since the inception of computerised numerical control for three-dimensional textile-manufacturing machines, technical textiles paved their way to numerous applications, certainly not limited to; aerospace, biomedical, civil engineering, defence, marine and medical industries. Digital interlooping and digital interlacing technology in additive manufacturing greatly advanced the manufacturing processes of textiles. In this work, we consider two branches of technical fabrics, namely plain-woven and weft-knitted. Multiscale modelling is the tool of choice for homogenising periodic structures and has been used extensively to model and analyse the mechanical behaviour of woven and knitted fabrics. But there is a plethora of literature discussing the demerits of such conventional multiscale modelling. These demerits include higher computational costs, rigid numerical models, ineffcient algorithmic computations and inability to incorporate geometric nonlinearities. We propose a data-driven nonlinear multiscale modelling technique to analyse the complex mechanical behaviour of plain-woven and weft-knitted fabrics with a neat extension to fabric material designing. We show how the integration of statistical learning techniques mitigates the weaknesses of conventional multiscale modelling. Moreover, we discuss the avenues that will open in many potential fields with regard to material modelling, structural engineering and textile industries. In the proposed data-driven nonlinear computational homogenisation technique, we effi ciently integrate the microscale and macroscale using Gaussian Process Regression (GPR) statistical learning technique. In the microscale, representative volume elements (RVEs) are modelled using nite deformable isogeometric spatial rods and deformation is homogenised using periodic boundary conditions. This nite deformable rod is profi cient in handling large deformations, rod-to-rod contacts, arbitrary cross-section de finitions and follower loads. Respecting the principle of separation of scales, we construct response databases by applying different homogenised strain states to the RVEs and recording the respective incremental volume-averaged energy values. We use GPR to learn a model using a 5-fold cross-validation technique by optimising the log marginal likelihood. In the macroscale, textiles are modelled as nonlinear orthotropic membranes for which the stresses and material constitutive relations are predicted by the trained GPR model. This coupling between GPR and membrane models is achieved through a systematic and seamless nite element integration using C++ and Python environments. A neat extension to material designing is also discussed with potentials to extend the work into other related fi elds.Cambridge trust and Trinity Hall scholarshi

Selected Papers from the First International Symposium on Future ICT (Future-ICT 2019) in Conjunction with 4th International Symposium on Mobile Internet Security (MobiSec 2019)

The International Symposium on Future ICT (Future-ICT 2019) in conjunction with the 4th International Symposium on Mobile Internet Security (MobiSec 2019) was held on 17–19 October 2019 in Taichung, Taiwan. The symposium provided academic and industry professionals an opportunity to discuss the latest issues and progress in advancing smart applications based on future ICT and its relative security. The symposium aimed to publish high-quality papers strictly related to the various theories and practical applications concerning advanced smart applications, future ICT, and related communications and networks. It was expected that the symposium and its publications would be a trigger for further related research and technology improvements in this field

Occupant protection design with FE human body models

The second leading cause of occupant fatalities in traffic accidents are thoracic injuries. Sternal fractures are the most typical moderate thoracic injury in frontal crash. Until now there is no clear understanding about the sternal injury mechanisms and how to minimize the risk of sternal fracture of the occupants. The design and assessment of advanced restraint systems capable to minimize such injuries is currently based on the Hybrid-III 50th percentile (H350) dummy in frontal crash. Despite the great benefits achieved with the H350 dummy, the inclusion of transducers and specific metrics for sternal loading were not part of its design purposes nor the representation of age-dependent factors. This suggests a gap of information in the design process of a restraint system. This gap could lead to an erroneous optimization of the system in terms of sternal injury risk minimization. It was hypothesized that the restraint design process needs to be complemented with more accurate and biofidelic tools, as human body models (HBMs), in terms of sternal loading minimization. A comparative analysis was needed. Three dimensions have been addressed in order to analyze the hypothesis: (i) Development of a novel elderly human model called Thums-elderly (based on the Thums-original) in order to address age-dependency factors and realistic geometrical properties of the thoracic cortical bone. This development included novel µCT data from PMHS and a multi-level validation process. (ii) Development of thoracic injury risk assessment methods for HBMs aiming for a direct comparison against dummy predictions. (iii) Comparison of the driver and passenger injury prediction of the dummy model and both HBMs (Thums-original and Thums-elderly) in a wide range of crash severities including a real-world accident reconstruction. A total of 168 occupant simulations were run and analyzed. The comparison addressed four different restraint systems including three adaptive restraint system variants. The assessment methods were grouped on rib fracture risk and sternal fracture risk. Sternal fracture risk was approached using HBM simulations by comparing two loadcases (non-injurious and injurious in terms of sternal fractures). Bending moments at the second inter-costal space (ICS_2) suggested to be a realistic criterion to quantify the risk of sternal fractures. An injury reference value of resultant moments at the second ICS “MXYZ ICS_2” of 20 Nm was proposed. Out of the benchmark crash cases, it was found that the H350 may underestimate the risk of thoracic injuries and sternal fractures particularly in frontal crash cases with considerably high lateral pulses. This is inherent to the H350 design purposes (frontal-crash dedicated dummy), nevertheless the dummy is currently still an injury prediction tool in assessment programs with crash cases precisely addressing lateral pulses as oblique barriers, offset deformable barriers, small-overlaps and accident reconstructions. For sternal fracture risk, the H350 is a not applicable tool, as this dummy was not designed to accurately measure sternal loading nor predict a risk of sternal fracture. An example of this fact was shown with the restraint system variant A (accident reconstruction case): A rather low AIS3 injury risk with the H350 indicated a safe design (at least for severe injuries) while no metrics of sternal loading or fracture risk were generated. The same variant tested with the HBMs showed an increased risk of sternal fracture. Restraint system variants (B, C and D) showed loading reduction with the HBMs up to non-injurious levels (under 20Nm). The same variants showed rather a marginal benefit with the H350. Lateral pulses are also believed to have an influence on the injury outcome of the front passengers, as the restraint system force transfer will be different due to the asymmetry of the belt paths. This effect is shown with the HBMs in terms of AIS2 (as sternal fracture). Regarding the effects of introducing age dependent factors (represented by the Thums-elderly), a reduced thorax stiffness was found in local- (component-) and body-region validation loadcases, specifically for cartilage, sternum and upper ribs. As the analysis was restricted to morphological dependency rather than material or failure limits, a “fragility” of the elderly model was not clearly represented. Nevertheless, the structural deformation is believed to be realistic due to the improvement achieved by introducing real cortical thicknesses from µCT data, especially on the sternal region. The Thums-elderly showed to be less sensitive, in terms of sternal loading, to successive shoulder belt force reduction than the Thums-original in high severity pulses. Sternal fractures and other moderate injuries will play an important role in the near future as optimization target in restraint system design. Sternal loading and sternal fracture risk need to be accurately predicted in order to assess the mitigation capabilities of a specific restraint system. While current dummies seem to be insufficient to reach the needed accuracy, HBMs show potential to assume this task. A simulation matrix with different crash severities and restraint system variants was built for benchmark purposes. The benchmark showed that current H350 dummies are not capable to discriminate noticeable improvements at sternal loading level, whereas HBMs do. Ageing and its effect on sternal fracture risk cannot be neither correctly represent with dummies. In order to represent ageing effects, HBMs need to be improved (e.g. realistic cortical thickness distribution and cartilage calcification). The injury prediction of an improved “elderly” HBM (Thums-elderly) showed to be strong dependent on the crash severity, although, it showed a less sensitive response to restraint loading reduction compared to the HBM without age-dependent factors (Thums-original).Nach Kopfverletzungen sind Thoraxverletzungen die zweithäufigste Todesursache bei Verkehrsunfällen. Darunter sind Brustbeinfrakturen die häufigsten mittelschweren Thorax-verletzungen in Frontalaufprall-Unfällen. Gegenwärtig gibt es weder eine eindeutige Erklärung bzgl. des Verletzungsmechanismus von Brustbeinfrakturen noch klare Strategien, um deren Risiko in der Insassenschutzauslegung zu minimieren. Die aktuelle Auslegung im Frontalaufprall basiert auf Messwerten des Hybrid-III 50th Prozent (H350) Dummys. Dessen Verletzungs-prognose anhand der gemessenen Werte lassen eine eingeschränkte Bewertung der Effektivität des Rückhaltesystems erstellen. Der Dummy und dessen Messtechnik mangelt an Sensoren spezifisch für die Bewertung von Brustbein-verletzungen. Darüber hinaus wurde eine altersabhängige Prognose nicht dazu mitentwickelt. Diese Fakten weisen auf eine inkomplette Analyse in der Insassenschutzauslegung für die Minimierung der Brustbeinverletzungen hin. Die Hypothese lautet deshalb, dass diese „Lücke“ des Hardware- und virtuellen Entwicklungsprozesses durch genauere und biofidelere Modelle (es entspricht Menschmodellen) gelöst werden kann. Eine vergleichende Analyse von Dummy vs. Menschmodell ist dazu erforderlich. Die Analyse der Hypothese erfolgte anhand drei Schritten: (i) Entwicklung eines neuen Menschmodells „Thums-elderly“ (basiert auf Thums-original), um altersabhängige Faktoren und realistischerer Kortikalis (Kortikalschicht) der Rippen nachzubilden. Diese Entwicklung enthält neuartige µCT Daten von PMHS und die Ergebnisse eines Mehrebenen-Validierungsprozesses. (ii) Entwicklung der Auswertungsmethoden spezifisch für Menschmodelle gezielt um die Vergleichbarkeit zur Dummy-Prognose zu gewährleisten. (iii) Vergleichende Analyse Dummy vs. Menschmodell auf Fahrer- und Beifahrerpositionen in einem breiteren Spektrum von Unfallschweren. Ein Realunfall wurde ebenfalls rekonstruiert und analysiert. Insgesamt wurden 168 Insassensimulationen durchgeführt und ausgewertet. Der Vergleich adressiert ebenso vier Rückhaltesystemvarianten, drei davon adaptiv. Die Auswertungsmethode der Simulationen mit Menschmodellen wurde in Rippenfrakturen und Brustbeinfrakturen unterteilt. Biegeversuche und Gurtstraffung wurden mit dem Menschmodell nachsimuliert, um Verletzungskriterien für Brustbeinfrakturen zu definieren und zu quantifizieren. Binäre Versuchsergebnisse (Verletzung oder Nicht-Verletzung) dienten als Referenz. Die Biegemomente auf ICS_2 (zweiter interkostalraum) zeigten sich als realistisches Kriterium). Als Verletzungsreferenzwert (IRV) ist ein resultierendes Biegemoment auf ICS_2 (MXYZ ICS_2) von 20 Nm vorgeschlagen. Anhand der simulierten Lastfälle wurde festgestellt, dass der H350 zu einer Unterprognose des Risikos der Thoraxverletzungen tendiert, insbesondere in Frontallastfällen mit erheblichen Lateralpulsen. Diese Unterprognose erklärt sich teilweise dadurch, dass der Dummy spezifisch für Frontalcrashanwendung ausgelegt wurde. Jedoch wird der Dummy aktuell noch als Auswertungstool in Gesetz- und Verbraucherschutzlastfälle eingesetzt, obwohl die oben genannten Lateralpulse präsent sind (z.B. Oblique- und Offset-deformable Barrieren, Small-overlaps und Unfallrekonstruktionen). Für eine Prognose der Brustbeinverletzungen ist der H350 weder dazu ausgelegt noch wurden Verletzungsrisikokurven spezifisch dafür entwickelt. Ein Beispiel dafür ist die Verletzungsprognose in der Unfallrekonstruktion (siehe Rückhaltesystem Variante A, Kapitel 4.3): Bei der Betrachtung der Ergebnisse liefert die Prognose des Dummys ein niedriges AIS3+ Verletzungsrisiko. Diese Prognose entspricht prinzipiell einer robusten Performance des Rückhaltesystems. Dabei ist zu beachten, dass keine Informationen bzgl. der Brustbein-belastungen bzw. dem Verletzungsrisiko generiert sind. Auf der anderen Seite weist die Simulation mit dem Menschmodell (ebenso Rückhaltesystem Variante A) ein höheres Verletzungsrisiko des Brustbeins auf. Darüber hinaus zeigten die Rückhaltesystemvarianten B, C und D eine stetige Reduktion der Belastung bis zu einem optimalen Punkt unter dem Verletzungsreferenzwert (20 Nm). Die gleichen Varianten mit dem H350 zeigen eine minimale Verbesserung, allerdings immer auf ein AIS3+ Niveau bezogen. Die Prognosegüte des Menschmodells weist zusätzlich darauf hin, dass die Verletzungs-wahrscheinlichkeit auch in Abhängigkeit der Insassenposition (Fahrer oder Beifahrer) zu betrachten ist, insbesondere bei Lastfällen mit Lateralpulsen, bei welchen die asymmetrische Konstellation der Schulter-gurtverlauf einem anderen Deformationsmuster des Brustkorbes entsprechen muss. Dieser Effekt ist nur mit dem Menschmodell quantifizierbar, wenn auf dem Beifahrerbrustbein gemessene Biegemomente vom Fahrerbrustbein abweichen. Bzgl. altersabhängigen Effekten weist die Anwendung von einem altersabhängigen Menschmodell (Thums-Elderly) eine reduzierte Steifigkeit auf. Dies geht aus der Validierung der Körperregion des Brustkorbs und einzelnen Komponenten insbesondere Knorpel, Brustbein und obere Rippen hervor. Die vergleichende Analyse mit dem Thums-elderly war beschränkt auf eine morphologische Abhängigkeit. Altersabhängige Materialparameter wie Fließkurven und Versagenskriterien blieben unverändert. Eine typische „Zerbrechlichkeit“ wurde mit dem modifizierten Modell nicht komplett abgebildet. Nichtsdestotrotz erreicht das Thums-elderly ein realistisches Deformationsmuster anhand der Anwendung von µCT Daten für die Kortikalis (Kortikalschicht) der Rippen und des Brustbeins. Das Thums-elderly weist zusätzlich eine geringere Sensitivität bei sukzessiver Senkung des Niveaus des Gurtkraftbegrenzers im Vergleich mit Thums-original auf. Allerdings ist dieser Effekt nur bei Lastfällen mit „härteren“ Pulsen zu erkennen. Brustbeinfrakturen und andere mittelschwere Verletzungen werden eine wichtige Rolle als Optimierungsziel bei der Auslegung zukünftiger Rückhaltesysteme spielen. Dazu ist eine realistische Prognose dieser Verletzungen notwendig, um eine korrekte Auslegung und Optimierung des Rückhaltesystems durchzuführen. Aktuelle Dummys sind nicht in der Lage, eine realistische Prognose dieser Verletzungen zu generieren. HBMs zeigen ein deutliches Potential, um diese Aufgabe zu übernehmen. Eine Simulationsmatrix mit einem breiten Spektrum von Crashschweren und Rückhaltsystemen wurde als Benchmarkbasis aufgebaut. Die Ergebnisse aus dem H350 zeigen bei einer stetigen Reduktion der Rückhaltbelastung keine Reduktion des Brustbeinverletzungsrisikos. Mit HBMs zeigt diese Reduktion jedoch eine deutliche Minimierung dieses Risikos. Eine Altersabhängigkeit des Brustbeinverletzungsrisikos ist nicht von aktuellen Dummys prognostizierbar. Nur optimierte HBMs werden altersabhängige Effekte korrekt nachbilden. Faktoren wie eine realistischere Kortikalschicht und ein korrektes Verknöcherungsmuster der Knorpel sind erforderlich. Die Verletzungsprognose eines optimierten „altersabhängigen“ HBM (Thums-elderly) zeigt eine starke Abhängigkeit von der Crashschwere, es zeigt jedoch eine geringere Sensitivität nach einer Reduktion der Rückhaltbelastung im Vergleich zu dem nicht-altersabhängigen HBM (Thums-original)