Le travail présenté dans ce mémoire a pour objectif le développement d'une nouvelle architecture pour les systèmes de vidéosurveillance. Tout d'abord, une étude bibliographique nous a conduit à classer les systèmes existants selon le niveau de leurs applications qui dépend directement des fonctions analytiques exécutées. Nous avons également constaté que les systèmes habituels traitent toutes les données enregistrées alors que réellement une faible partie des scènes sont utiles pour l'analyse. Ainsi, nous avons étendu l'architecture ordinaire des systèmes de surveillance par une phase de pré-analyse qui extrait et simplifie les régions d'intérêt en conservant les caractéristiques importantes. Deux méthodes différentes pour la pré-analyse dans le contexte de la vidéosurveillance ont été proposées : une méthode de filtrage spatio-temporel et une technique de modélisation des objets en mouvement. Nous avons contribué, aussi, par l'introduction du concept de la scalabilité orientée vers l'application à travers une architecture multi-niveaux applicatifs pour les systèmes de surveillance. Les différents niveaux d'applications des systèmes de vidéosurveillance peuvent être atteints incrémentalement pour répondre aux besoins progressifs de l'utilisateur final. Un exemple de système de vidéosurveillance respectant cette architecture et utilisant nos méthodes de pré-analyse est proposé. / The work presented in this thesis aims to develop a new architecture for video surveillance systems. Firstly, a literature review has led to classify the existing systems based on their applications level which dependents directly on the performed analytical functions. We, also, noticed that the usual systems treat all captured data while, actually, a small part of the scenes are useful for analysis. Hence, we extended the common architecture of surveillance systems with a pre-analysis phase that extracts and simplifies the regions of interest with keeping the important characteristics. Two different methods for preanalysis were proposed : a spatio-temporal filtering and a modeling technique for moving objects. We contributed, too, by introducing the concept of application-oriented scalability through a multi-level application architecture for surveillance systems. The different applications levels can be reached incrementally to meet the progressive needs of the enduser. An example of video surveillance system respecting this architecture and using the preanalysis methods was proposed.

Activated Partial Thromboplastin Time (APTT) is a screening method used to detect defects in the intrinsic pathway. Different preanalytical variables such as centrifugation and thawing can affect the given test results from APTT analysis. The purpose of the study was to evaluate how the results for APTT were affected when frozen citrate plasma was thawed in a heating cabinet or a water bath, and how the results for APTT were affected if the samples were single or double centrifuged before freezing. A total of 40 fresh samples were collected for each study purpose and analyzed. To study how thawing conditions affected frozen samples, aliquoted plasma was frozen at –20°C for a week and then thawed in either a water bath or in a heating cabinet. To study how single and double centrifugation affected the test results, one of the two aliquots per sample was centrifuged again while the other remained single centrifuged. The samples were then stored frozen for one week and afterwards thawed. The results showed statistically significant differences between fresh samples and frozen samples thawed in a heath incubator or water bath. Regarding centrifugation conditions, both single and double centrifugation yielded statistically significant differences in comparison to fresh plasma. All the evaluated sample treatments showed statistically significant differences in comparison to fresh samples. However, in all cases the mean percentage change was ≤10%, which indicates no clinical significance. In conclusion APTT-samples seem to be sensitive to preanalytical variables and further studies are needed to evaluate their effects.