5 research outputs found

    Analyse de mouvements faciaux à partir d'images vidéo

    Full text link
    Lors d'une intervention conversationnelle, le langage est supportĂ© par une communication non-verbale qui joue un rĂŽle central dans le comportement social humain en permettant de la rĂ©troaction et en gĂ©rant la synchronisation, appuyant ainsi le contenu et la signification du discours. En effet, 55% du message est vĂ©hiculĂ© par les expressions faciales, alors que seulement 7% est dĂ» au message linguistique et 38% au paralangage. L'information concernant l'Ă©tat Ă©motionnel d'une personne est gĂ©nĂ©ralement infĂ©rĂ©e par les attributs faciaux. Cependant, on ne dispose pas vraiment d'instruments de mesure spĂ©cifiquement dĂ©diĂ©s Ă  ce type de comportements. En vision par ordinateur, on s'intĂ©resse davantage au dĂ©veloppement de systĂšmes d'analyse automatique des expressions faciales prototypiques pour les applications d'interaction homme-machine, d'analyse de vidĂ©os de rĂ©unions, de sĂ©curitĂ©, et mĂȘme pour des applications cliniques. Dans la prĂ©sente recherche, pour apprĂ©hender de tels indicateurs observables, nous essayons d'implanter un systĂšme capable de construire une source consistante et relativement exhaustive d'informations visuelles, lequel sera capable de distinguer sur un visage les traits et leurs dĂ©formations, permettant ainsi de reconnaĂźtre la prĂ©sence ou absence d'une action faciale particuliĂšre. Une rĂ©flexion sur les techniques recensĂ©es nous a amenĂ© Ă  explorer deux diffĂ©rentes approches. La premiĂšre concerne l'aspect apparence dans lequel on se sert de l'orientation des gradients pour dĂ©gager une reprĂ©sentation dense des attributs faciaux. Hormis la reprĂ©sentation faciale, la principale difficultĂ© d'un systĂšme, qui se veut ĂȘtre gĂ©nĂ©ral, est la mise en Ɠuvre d'un modĂšle gĂ©nĂ©rique indĂ©pendamment de l'identitĂ© de la personne, de la gĂ©omĂ©trie et de la taille des visages. La dĂ©marche qu'on propose repose sur l'Ă©laboration d'un rĂ©fĂ©rentiel prototypique Ă  partir d'un recalage par SIFT-flow dont on dĂ©montre, dans cette thĂšse, la supĂ©rioritĂ© par rapport Ă  un alignement conventionnel utilisant la position des yeux. Dans une deuxiĂšme approche, on fait appel Ă  un modĂšle gĂ©omĂ©trique Ă  travers lequel les primitives faciales sont reprĂ©sentĂ©es par un filtrage de Gabor. MotivĂ© par le fait que les expressions faciales sont non seulement ambigĂŒes et incohĂ©rentes d'une personne Ă  une autre mais aussi dĂ©pendantes du contexte lui-mĂȘme, Ă  travers cette approche, on prĂ©sente un systĂšme personnalisĂ© de reconnaissance d'expressions faciales, dont la performance globale dĂ©pend directement de la performance du suivi d'un ensemble de points caractĂ©ristiques du visage. Ce suivi est effectuĂ© par une forme modifiĂ©e d'une technique d'estimation de disparitĂ© faisant intervenir la phase de Gabor. Dans cette thĂšse, on propose une redĂ©finition de la mesure de confiance et introduisons une procĂ©dure itĂ©rative et conditionnelle d'estimation du dĂ©placement qui offrent un suivi plus robuste que les mĂ©thodes originales.In a face-to-face talk, language is supported by nonverbal communication, which plays a central role in human social behavior by adding cues to the meaning of speech, providing feedback, and managing synchronization. Information about the emotional state of a person is usually carried out by facial attributes. In fact, 55% of a message is communicated by facial expressions whereas only 7% is due to linguistic language and 38% to paralanguage. However, there are currently no established instruments to measure such behavior. The computer vision community is therefore interested in the development of automated techniques for prototypic facial expression analysis, for human computer interaction applications, meeting video analysis, security and clinical applications. For gathering observable cues, we try to design, in this research, a framework that can build a relatively comprehensive source of visual information, which will be able to distinguish the facial deformations, thus allowing to point out the presence or absence of a particular facial action. A detailed review of identified techniques led us to explore two different approaches. The first approach involves appearance modeling, in which we use the gradient orientations to generate a dense representation of facial attributes. Besides the facial representation problem, the main difficulty of a system, which is intended to be general, is the implementation of a generic model independent of individual identity, face geometry and size. We therefore introduce a concept of prototypic referential mapping through a SIFT-flow registration that demonstrates, in this thesis, its superiority to the conventional eyes-based alignment. In a second approach, we use a geometric model through which the facial primitives are represented by Gabor filtering. Motivated by the fact that facial expressions are not only ambiguous and inconsistent across human but also dependent on the behavioral context; in this approach, we present a personalized facial expression recognition system whose overall performance is directly related to the localization performance of a set of facial fiducial points. These points are tracked through a sequence of video frames by a modification of a fast Gabor phase-based disparity estimation technique. In this thesis, we revisit the confidence measure, and introduce an iterative conditional procedure for displacement estimation that improves the robustness of the original methods

    Organising a photograph collection based on human appearance

    Get PDF
    This thesis describes a complete framework for organising digital photographs in an unsupervised manner, based on the appearance of people captured in the photographs. Organising a collection of photographs manually, especially providing the identities of people captured in photographs, is a time consuming task. Unsupervised grouping of images containing similar persons makes annotating names easier (as a group of images can be named at once) and enables quick search based on query by example. The full process of unsupervised clustering is discussed in this thesis. Methods for locating facial components are discussed and a technique based on colour image segmentation is proposed and tested. Additionally a method based on the Principal Component Analysis template is tested, too. These provide eye locations required for acquiring a normalised facial image. This image is then preprocessed by a histogram equalisation and feathering, and the features of MPEG-7 face recognition descriptor are extracted. A distance measure proposed in the MPEG-7 standard is used as a similarity measure. Three approaches to grouping that use only face recognition features for clustering are analysed. These are modified k-means, single-link and a method based on a nearest neighbour classifier. The nearest neighbour-based technique is chosen for further experiments with fusing information from several sources. These sources are context-based such as events (party, trip, holidays), the ownership of photographs, and content-based such as information about the colour and texture of the bodies of humans appearing in photographs. Two techniques are proposed for fusing event and ownership (user) information with the face recognition features: a Transferable Belief Model (TBM) and three level clustering. The three level clustering is carried out at “event” level, “user” level and “collection” level. The latter technique proves to be most efficient. For combining body information with the face recognition features, three probabilistic fusion methods are tested. These are the average sum, the generalised product and the maximum rule. Combinations are tested within events and within user collections. This work concludes with a brief discussion on extraction of key images for a representation of each cluster

    Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields

    Get PDF
    Innovations in Road, Railway and Airfield Bearing Capacity – Volume 1 comprises the first part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field

    Using MapReduce Streaming for Distributed Life Simulation on the Cloud

    Get PDF
    Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

    Volume 1 – Symposium

    Get PDF
    We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group A: Materials Group B: System design & integration Group C: Novel system solutions Group D: Additive manufacturing Group E: Components Group F: Intelligent control Group G: Fluids Group H | K: Pumps Group I | L: Mobile applications Group J: Fundamental
    corecore