L’amplitude articulaire maximale (AAM) ou flexibilité, est un paramètre fonctionnel fréquemment utilisé dans la pratique clinique, sportive et au sein des protocoles de recherche pour estimer la longueur maximale de l'unité muscle-tendon (UMT). Il a longtemps été considéré que l’AAM est limitée par la tension développée par les UMTs étirées pendant le mouvement articulaire (mechanical theory). Cependant, un nombre important de recherches expérimentales suggèrent que l’étirement peut induire une augmentation de l’AAM en absence d'adaptations mécaniques significatives dans l’UTM (sensory-based theory). Récemment, les structures non-musculaires telles que les nerfs périphériques ont été suggérées comme facteurs limitant l'amplitude d'étirement. Cette thèse vise à mieux comprendre le rôle mécanique des tissus musculaires et nonmusculaires qui peuvent influencer la limitation de l’AAM in-vivo. En utilisant la technique d’élastographie permettant d’évaluer la raideur passive des muscles et des nerfs individuellement, quatre études ont été réalisées pour : déterminer si l’étirement des structures musculaires et non musculaires limite l’AAM et si les propriétés mécaniques des tissus étirés s'adaptent à l’étirement aigu ou chronique. Les résultats ont montré que l’AAM peut être limitée par des structures musculaires ou non-musculaires. Le positionnement des articulations du membre inferieur est décisif pour étirer de manière spécifique le tissu ciblé et induire des changements au niveau des propriétés mécaniques des muscles et des nerfs après l’application des protocoles d’étirement aigus et chroniques. De plus l’amélioration de l’AAM était spécifique selon les tissus étirés. / Maximal joint range of motion (ROM) of a joint, or joint flexibility, is an important functional outcome used in clinical practice, sports and research designs to estimate the maximal length of passive muscle-tendon unit (MTU). Maximal ROM was thought to be mainly restricted by the tension developed by MTUs being stretched during articular motion (mechanical-based theory). However, there is a growing body of experimental research suggesting that stretch training induces increases in maximal ROM in the absence of significant mechanical adaptations in MTU (sensorybased theory). More recently, non-muscular structures such as peripheral nerves have been pointed to limit the stretching amplitude. This doctoral research aimed to extend the knowledge about the mechanical role of muscular and non-muscular tissues underpinning the limitation of maximal ROM in-vivo. Taking advantage of ultrasound shear wave elastography to assess the passive stiffness of individual muscles and nerve, four studies were conducted to: examine whether mechanical loading of muscular and non-muscular structures limit the maximal ROM, and if their mechanical properties adapt to either acute or chronic stretch training. The results show that maximal ROM can be limited by either muscular or non-muscular structures, depending on the posture of the entire lower limb which is decisive to stretch preferentially the target tissue. Acute and chronic stretching targeting separately each structure induces changes in mechanical properties of muscles and nerves. In addition, improvements in maximal ROM were specific to the tissues that were more loaded and correlated with the changes in their mechanical properties.

Radiotherapy is the most widely used treatment for cancer, with 4 out of 10 cancer patients receiving radiotherapy as part of their treatment. The delineation of gross tumour volume (GTV) is crucial in the treatment of radiotherapy. An automatic contouring system would be beneficial in radiotherapy planning in order to generate objective, accurate and reproducible GTV contours. Image guided radiotherapy (IGRT) acquires patient images just before treatment delivery to allow any necessary positional correction. Consequently, real-time contouring system provides an opportunity to adopt radiotherapy on the treatment day. In this thesis, freely deformable models (FDM) and shape constrained deformable models (SCDMs) were used to automatically delineate the GTV for brain cancer and prostate cancer. Level set method (LSM) is a typical FDM which was used to contour glioma on brain MRI. A series of low level image segmentation methodologies are cascaded to form a case-wise fully automatic initialisation pipeline for the level set function. Dice similarity coefficients (DSCs) were used to evaluate the contours. Results shown a good agreement between clinical contours and LSM contours, in 93% of cases the DSCs was found to be between 60% and 80%. The second significant contribution is a novel development to the active shape model (ASM), a profile feature was selected from pre-computed texture features by minimising the Mahalanobis distance (MD) to obtain the most distinct feature for each landmark, instead of conventional image intensity. A new group-wise registration scheme was applied to solve the correspondence definition within the training data. This ASM model was used to delineated prostate GTV on CT. DSCs for this case was found between 0.75 and 0.91 with the mean DSC 0.81. The last contribution is a fully automatic active appearance model (AAM) which captures image appearance near the GTV boundary. The image appearance of inner GTV was discarded to spare the potential disruption caused by brachytherapy seeds or gold markers. This model outperforms conventional AAM at the prostate base and apex region by involving surround organs. The overall mean DSC for this case is 0.85.

<p>This thesis aims at building a system capable of automatically extracting and parameterizing the position of a face and its features in images acquired from a low-end monocular camera. Such a challenging task is justified by the importance and variety of its possible applications, ranging from face and expression recognition to animation of virtual characters using video depicting real actors. The implementation includes the construction of Active Appearance Models of the human face from training images. The existing face model Candide-3 is used as a starting point, making the translation of the tracking parameters to standard MPEG-4 Facial Animation Parameters easy.</p><p>The Inverse Compositional Algorithm is employed to adapt the models to new images, working on a subspace where the appearance is "projected out" and thus focusing only on shape.</p><p>The algorithm is tested on a generic model, aiming at tracking different people’s faces, and on a specific model, considering one person only. In the former case, the need for improvements in the robustness of the system is highlighted. By contrast, the latter case gives good results regarding both quality and speed, with real time performance being a feasible goal for future developments.</p>

Le visage joue un rôle prépondérant en langue des signes, notamment par le sens porté par ses expressions. Peu d'études existent sur les expressions faciales en langue des signes ; cela est dû au manque d'outil de description. Dans cette thèse, il s'agit de développer des méthodes permettant la description la plus précise et exhaustive possible des différents mouvements faciaux observables au cours d'une séquence vidéo de langue des signes.<br /><br />Le formalisme des modèles à apparence active (Active Appearance Models - AAM) est utilisé ici pour modéliser le visage en termes de déplacements d'un certain nombre de points d'intérêt et en termes de variations de texture. Quand il est associé à une méthode d'optimisation, ce formalisme permet de trouver les coordonnées des points d'intérêt sur un visage. Nous utilisons ici une méthode d'optimisation dite "à composition inverse", qui permet une implémentation efficace et l'obtention de résultats précis.<br /><br />Dans le contexte de la langue des signes, les rotations hors-plan et les occultations manuelles sont fréquentes. Il est donc nécessaire de développer des méthodes robustes à ces conditions. Il existe pour cela une variante robuste des méthodes d'optimisation d'AAM qui permet de considérer une image d'entrée éventuellement bruitée.<br />Nous avons étendu cette variante de façon à ce que la détection des occultations puisse se faire de manière automatique, en supposant connu le comportement de l'algorithme dans le cas non-occulté.<br />Le résultat de l'algorithme est alors constitué des coordonnées 2D de chacun des points d'intérêt du modèle en chaque image d'une séquence vidéo, associées éventuellement à un score de confiance. Ces données brutes peuvent ensuite être exploitées dans plusieurs applications.<br /><br />Nous proposons ainsi comme première application de décrire une séquence vidéo expressive en chaque instant par une combinaison de déformations unitaires activées à des intensités différentes. Une autre application originale consiste à traiter une vidéo de manière à empêcher l'identification d'un visage sans perturber la reconnaissance de ses expressions.

在電腦硬體快速發展的時代，以前被視為只能在工作站上執行的3D繪圖現今也可以輕易地在普通的家用電腦上執行。藉著網路視訊攝影機低廉的價格以及其普及化的趨勢，我們設計一套兼顧快速以及經濟性的系統。使用者可以輕易自行架構攝影環境，不需專業的操作便可以自動產生立體的人臉誇張模型。另一方面我們改良並結合先前的2D誇張肖像漫畫研究，除了大幅提升五官定位的精確度外，藉著替換多張參考畫作，產生出來的模型可以呈現不同藝術風格的外觀，以供廣泛的娛樂用途。 / With the advances of hardware nowadays, the computation and demonstration of 3D graphics are readily attained on a personal computer. At the same time, thanks to the prevalence of instant messaging software, webcam has become very popular. These combined factors have motivated us to design an economic and effective solution for general users to create their own 3D caricature models without complex procedures or instructions. In this thesis, we have developed a system which can extract and analyze facial features from an image pair captured by two webcams, and then generate a 3D face model based on it. Specifically, we improved previous research to obtain more accurate feature locations, and extended the exaggeration algorithm to generate more impressive effects. By fusing a caricature produced with different work as references, the system is capable of painting the face model with various artists’ styles.

This master's thesis considers methods of face recognition. There are described methods with different approachs: knowledge-based methods, feature invariant approaches, template matching methods and appearance-based methods. This master's thesis is focused particulary on template matching method and statistical methods like a principal component analysis (PCA) and linear discriminant analysis (LDA). There are described in detail template matching methods like active shape models (ASM) and active appearance models (AAM).

Recently, automatic age progression has gained popularity due to its numerous applications. Among these is the frequent search for missing people, in the UK alone up to 300,000 people are reported missing every year. Although many algorithms have been proposed, most of the methods are affected by image noise, illumination variations, and facial expressions. Furthermore, most of the algorithms use a pattern caricaturing approach which infers ages by manipulating the target image and a template face formed by averaging faces at the intended age. To this end, this thesis investigates the problem with a view to tackling the most prominent issues associated with the existing algorithms. Initially using active appearance models (AAM), facial features are extracted and mapped to people’s ages, afterward a formula is derived which allows the convenient generation of age progressed images irrespective of whether the intended age exists in the training database or not. In order to handle image noise as well as varying facial expressions, a nonlinear appearance model called kernel appearance model (KAM) is derived. To illustrate the real application of automatic age progression, both AAM and KAM based algorithms are then used to synthesise faces of two popular long missing British and Irish kids; Ben Needham and Mary Boyle. However, both statistical techniques exhibit image rendering artefacts such as low-resolution output and the generation of inconsistent skin tone. To circumvent this problem, a hybrid texture enhancement pipeline is developed. To further ensure that the progressed images preserve people’s identities while at the same time attaining the intended age, rigorous human and machine based tests are conducted; part of this tests resulted to the development of a robust age estimation algorithm. Eventually, the results of the rigorous assessment reveal that the hybrid technique is able to handle all existing problems of age progression with minimal error. / National Information Technology Development Agency of Nigeria (NITDA)

The diploma thesis is focused on the development of composites from alkali activated materials (AAM) and their resistance to extreme temperatures. The theoretical part describes alkaline activation and precursors for the production of AAM. Furthermore, the problem of the effect of extreme temperatures on these materials is described. In the experimental part, the optimal silicate modulus with respect to the properties of AAM was gradually determined, and the effect of extreme temperatures on the AAM matrix was verified. In the next stage, the effect of the filler with respect to the behavior at extreme temperatures was tested and then the final formulation was optimized.

Reliability worth analysis is an important tool for distribution systems planning and operations. The interruption cost model used in the analysis directly affects the accuracy of the reliability worth evaluation. In this dissertation, the reliability worth analysis was dealt with two interruption cost models including an average or aggregated model (AAM), and a probabilistic distribution model (PDM) in two phases. In the first phase, the dissertation presents a reliability cost model based AAM for distribution system planning. The reliability cost model has been derived as a linear function of line flows for evaluating the outages. The objective is to minimize the total cost including the outage cost, feeder resistive loss, and fixed investment cost. The Evolutionary Programming (EP) was used to solve the very complicated mixed-integer, highly non-linear, and non-differential problem. A real distribution network was modeled as the sample system for tests. There is also a higher opportunity to obtain the global optimum during the EP process. In the second phase, the interruption cost model PDM was proposed by using the radial basis function (RBF) neural network with orthogonal least-squares (OLS) learning method. The residential and industrial interruption costs in PDM were integrated by the proposed neural network technique. A Monte-Carlo time sequential simulation technique was adopted for worth assessment. The technique is tested by evaluating the reliability worth of a Taipower system for the installation of disconnected switches, lateral fuses, transformers and alternative supplies. The results show that the two cost models result in very different interruption costs, and PDM may be more realistic in modeling the system.

This thesis aims at building a system capable of automatically extracting and parameterizing the position of a face and its features in images acquired from a low-end monocular camera. Such a challenging task is justified by the importance and variety of its possible applications, ranging from face and expression recognition to animation of virtual characters using video depicting real actors. The implementation includes the construction of Active Appearance Models of the human face from training images. The existing face model Candide-3 is used as a starting point, making the translation of the tracking parameters to standard MPEG-4 Facial Animation Parameters easy. The Inverse Compositional Algorithm is employed to adapt the models to new images, working on a subspace where the appearance is "projected out" and thus focusing only on shape. The algorithm is tested on a generic model, aiming at tracking different people’s faces, and on a specific model, considering one person only. In the former case, the need for improvements in the robustness of the system is highlighted. By contrast, the latter case gives good results regarding both quality and speed, with real time performance being a feasible goal for future developments.