No description available.

No description available.

The work in this thesis aims at studying the problems related to the robustness of a face recognition system where specific attention is given to the issues of handling the image variation complexity and inherent limited Unique Characteristic Information (UCI) within the scope of unfamiliar identity recognition environment. These issues will be the main themes in developing a mutual understanding of extraction and classification tasking strategies and are carried out as a two interdependent but related blocks of research work. Naturally, the complexity of the image variation problem is built up from factors including the viewing geometry, illumination, occlusion and other kind of intrinsic and extrinsic image variation. Ideally, the recognition performance will be increased whenever the variation is reduced and/or the UCI is increased. However, the variation reduction on 2D facial images may result in loss of important clues or UCI data for a particular face alternatively increasing the UCI may also increase the image variation. To reduce the lost of information, while reducing or compensating the variation complexity, a hybrid technique is proposed in this thesis. The technique is derived from three conventional approaches for the variation compensation and feature extraction tasks. In this first research block, transformation, modelling and compensation approaches are combined to deal with the variation complexity. The ultimate aim of this combination is to represent (transformation) the UCI without losing the important features by modelling and discard (compensation) and reduce the level of the variation complexity of a given face image. Experimental results have shown that discarding a certain obvious variation will enhance the desired information rather than sceptical in losing the interested UCI. The modelling and compensation stages will benefit both variation reduction and UCI enhancement. Colour, gray level and edge image information are used to manipulate the UCI which involve the analysis on the skin colour, facial texture and features measurement respectively. The Derivative Linear Binary transformation (DLBT) technique is proposed for the features measurement consistency. Prior knowledge of input image with symmetrical properties, the informative region and consistency of some features will be fully utilized in preserving the UCI feature information. As a result, the similarity and dissimilarity representation for identity parameters or classes are obtained from the selected UCI representation which involves the derivative features size and distance measurement, facial texture and skin colour. These are mainly used to accommodate the strategy of unfamiliar identity classification in the second block of the research work. Since all faces share similar structure, classification technique should be able to increase the similarities within the class while increase the dissimilarity between the classes. Furthermore, a smaller class will result on less burden on the identification or recognition processes. The proposed method or collateral classification strategy of identity representation introduced in this thesis is by manipulating the availability of the collateral UCI for classifying the identity parameters of regional appearance, gender and age classes. In this regard, the registration of collateral UCI s have been made in such a way to collect more identity information. As a result, the performance of unfamiliar identity recognition positively is upgraded with respect to the special UCI for the class recognition and possibly with the small size of the class. The experiment was done using data from our developed database and open database comprising three different regional appearances, two different age groups and two different genders and is incorporated with pose and illumination image variations.

No description available.

L'objectif de cette thèse est d'étudier la formation et le contrôle de structures spatiales apparaissant dans un cristal photoréfractif soumis à une simple boucle de rétro-action optique (simple feedback). Suite au mécanisme d'instabilité de modulation, un faisceau laser entrant dans un milieu non linéaire peut subir une structuration spatiale transverse,connue sous le nom de filamentation. Dans la configuration dite simple feedback, l'interaction de deux faisceaux laser contra-propageants peut donner naissance à des structures transverses auto-organisées (dites patterns) plus régulières que les filaments : par exemple une structure de type hexagonal. Dans ce document, nous étudions, à la fois théoriquement et expérimentalement le phénomène de formation de patterns photoréfractifs. Notre but est d'aller au-delà de la simple observation de patterns. En effet, nous focalisons notre étude sur l'adressage et la sélection de patterns, en utilisant les propriétés de contrôle de la lumière que fournissent les structures périodiques telles que les cristaux photoniques. L'insertion de telles structures au sein même du milieunon linéaire photoréfractif permet la création, la sélection et l'orientation de différents patterns. La géométrie, la vélocité et la dynamique de ces structures spatiales sont également fortement influencées lorsqu'un décalage transverse, induit par un désalignement du miroir de rétro-action, est imposé au système. Ainsi, pour la première fois dans un système photoréfractif, il devient possible d'observer des dynamiques dites convectives, c'est-à-dire entretenues par le bruit. Pour finir, une partie de cette thèse est dédiée à l'obtention de structures dites localisées. Trouvant leur originalité dans des applications comme les mémoires optiques adressables, ces structures ont été intensément étudiées ces dernière années. Nous proposons de les observer dans notre système photoréfractif, peu voire pas étudié dans cette configuration / The aim of the present manuscript is to study the formation and the controlof transverse structures in nonlinear optical systems by using photorefractivematerials as the optical nonlinear medium. A single laser beam entering insuch a nonlinear medium can experience transverse structuring due to themechanisms of modulation instability, which may lead to beam filamentation.In another case, the interaction of two beams may lead to spatially regularpatterns, as in the case of the single-feedback configuration.In this study, we focus on the conditions for the appearance of ordered patternedstructures and describe the theoretical and experimental background forthe observation of these effects. Our challenge is to go beyond the observation,classification and understanding of the nonlinear phenomena encountered. Weare especially interested in the properties of the free-running nonlinear system,combined with different control mechanisms. Principally, on one hand, we focuson the active addressing, selection and orientation of a desired pattern bysuitably using a periodic photonic structures as the control mechanisms.On the other hand, the dynamics, the geometry, and the velocity of thedifferent patterns are strongly influenced by an imposed misalignment of themirror producing the optical feedback. Consequently, convective dynamics, sustainedby noise, are expected in the system and will be observed for the firsttime in a photorefractive experiment.Finally, a part of the manuscript is devoted to the observation of localizedstructures. Potentially useful for optical memories, these structures have beenintensively studied in different configurations, but experiments in photorefractivematerials remain scarce. Thus, we will focus

This work is exploring the rectangle as a pattern construction. It is the most recognised geometric shape, can it still provide us with new expressions in fashion? This project is conducted through clear restrictions in the method, and through draping translated into garments through flat pattern construction. The result is a collection with a complex expression, mixing poetic shapes with playful prints full of contrast, which signifes harmony but does not follow the classical notions of beauty. The value of this work lies in the finding of new expressions in fashion, proposing that it is of utmost importance to challenge what we think we know to be true.

The study attempts to determine the degree of powerlessness and the deferment of gratification among children as measured by instruments designed for this purpose. An effort will be made to test whether the deferred gratification pattern exists in inverse relationship to the feeling of powerlessness among the lower classes; and to determine whether children who feel they are estranged from society have a psychological need for an impulsive release of feelings.

Humans are well suited to the reading of textual information, but unfortunately it has not yet been possible to develop a machine to emulate this form of human behaviour. In the past, machines have been characterised by having static forms of specific knowledge necessary for character recognition. The resulting form of reading behaviour is most uncharacteristic of the way humans perceive textual information. The major problem with handprinted character recognition is the infinite variability in the character shapes and the ambiguities many of these shapes exhibit. Human perception of handprinted characters makes extensive use of "world knowledge" to remove such ambiguities. Humans are also continually modifying their world knowledge to further enhance their reading behaviour by acquiring new knowledge as they read. An information processing model for perception and learning of handprinted characters is proposed. The function of the model is to enable ambiguous character descriptions to converge to single character classifications. The accuracy of this convergence improves with reading experience on handprinted text. The model consists of three compon,ent parts. Firstly, a character classifier to recognise character patterns. These patterns may be both distorted anq noisy, where distortion is defined to be a consistent variability from known archetypical character descriptions and noise as a random inconsistent variability in character shape. Secondly, a perceptive mechanism that makes inferences from an incomplete linguistic world model of an author or of a specific domain of discourse from many authors. Finally, a incremental learning capability is integrated into the character classifier and perceptive mechanisms. This is to enable the internal world model to be continually adaptive to either changes in the domain of discourse or to different authors. A demonstrator is described, together with a summary of experimental results that clearly show the improvement in machine perception which results from continuous incremental learning.

Includes folded charts in pocket. / Digitized by Kansas Correctional Industries

Turing theory plays an important role in real biological pattern formation problems, such as solid tumor growth and animal coat patterns. To understand how patterns form and develop over time due to growth, we consider spatiotemporal patterns, in particular Turing patterns, for reaction diffusion systems on growing surfaces with curvature. Of particular interest is isotropic growth of the sphere, where growth of the domain occurs in the same proportion in all directions. Applying a modified linear stability analysis and a separation of timescales argument, we derive the necessary and sufficient conditions for a diffusion driven instability of the steady state and for the emergence of spatial patterns. Finally, we explore these results using numerical simulations.