Automatic face recognition has long been studied because it has a wide potential for application. Several systems have been developed to identify faces from small face populations via detailed face feature analysis, or by using neural nets, or through model based approaches. This study has aimed to provide satisfactory recognition within large populations of human faces and has concentrated on improving feature definition and extraction to establish an extended feature set to lead to a fully structured recognition system based on a single frontal view. An overall review on the development and the techniques of automatic face recognition is included, and performances of earlier systems are discussed. A novel profile description has been achieved from a frontal view of a face and is represented by a Walsh power spectrum which was selected from seven different descriptions due to its ability to distinguish the differences between profiles of different faces. A further feature has concerned the face contour which is extracted by iterative curve fitting and described by normalized Fourier descriptors. To accompany an extended set of geometric measurements, the eye region feature is described statistically by eye-centred moments. Hair texture has also been studied for the purpose of segmenting it from other parts of the face and to investigate the possibility of using it as a set of feature. These new features combine to form an extended feature vector to describe a face. The algorithms for feature extraction have been implemented on face images from different subjects and multiple views from the same person but without the face normal to the camera or without constant illumination. Features have been assessed in consequence on each feature set separately and on the composite feature vector. The results have continued to emphasize that though each description can be used to recognise a face there is a clear need for an extended feature set to cope with the requirements of recognizing faces within large populations.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaf 81). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaf 81). Also available on the Internet.

Typescript. Includes bibliographical references (leaves 96-99).

The traditional view of vision is that neurons in early cortical areas process information about simple features (e.g. orientation and spatial frequency) in small, spatially localised regions of visual space (the neuron's receptive field). This piecemeal information is then fed-forward into later stages of the visual system where it gets combined to form coherent and meaningful global (higher-level) representations. The overall aim of this thesis is to examine and quantify this higher level processing; how we encode global features in natural images and to understand the extent to which our perception of these global representations is determined by the local features within images. Using the tilt after-effect as a tool, the first chapter examined the processing of a low level, local feature and found that the orientation of a sinusoidal grating could be encoded in both a retinally and spatially non-specific manner. Chapter 2 then examined these tilt aftereffects to the global orientation of the image (i.e., uprightness). We found that image uprightness was also encoded in a retinally / spatially non-specific manner, but that this global property could be processed largely independently of its local orientation content. Chapter 3 investigated if our increased sensitivity to cardinal (vertical and horizontal) structures compared to inter-cardinal (45° and 135° clockwise of vertical) structures, influenced classification of unambiguous natural images. Participants required relatively less contrast to classify images when they retained near-cardinal as compared to near-inter-cardinal structures. Finally, in chapter 4, we examined category classification when images were ambiguous. Observers were biased to classify ambiguous images, created by combining structures from two distinct image categories, as carpentered (e.g., a house). This could not be explained by differences in sensitivity to local structures and is most likely the result of our long-term exposure to city views. Overall, these results show that higher-level representations are not fully dependent on the lower level features within an image. Furthermore, our knowledge about the environment influences the extent to which we use local features to rapidly identify an image.

Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 133. Thesis directors: Zoran Duric, Dana Richards. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science. Title from PDF t.p. (viewed Mar. 17, 2009). Includes bibliographical references (p. 127-132). Also issued in print.

Thesis (Ph. D.)--State University of New York at Binghamton, Computer Science Department, 2006. / Includes bibliographical references.

[pt] Os minérios, uma vez extraídos, passam por diversas etapas de beneficiamento antes que possam ser devidamente utilizados. Os finos de minérios que, ao final dessa etapa, não possuem a granulometria necessária para alimentar os fornos de redução, passam por processos de aglomeração para alcançá-la, como a pelotização e a sinterização, cujo material produzido em uma das etapas deste último processo é o foco do presente trabalho. Esses finos passam primeiramente por uma etapa de microaglomeração, que é fundamental para o processo, pois muitas das características e propriedades do sínter são função da estrutura do microaglomerado pré-tratamento térmico. Ela consiste numa mistura do sinter feed com água, fundentes e combustível sólido (coque). Existem 3 estruturas típicas para um microaglomerado: quasipartícula, micropelota e partícula não aglomerada. A presente dissertação desenvolveu uma rotina automática no programa de processamento e análise de imagens FIJI, baseada em processamento e análise de imagens do microaglomerado obtidas por microscópio ótico, que é capaz de identificar as partículas de diferentes granulometrias que compõem a amostra, e classificá-las quanto às 3 classes supramencionadas. Após a classificação, a rotina é capaz de extrair atributos dos objetos identificados (percentual de cada classe, circularidade média, espessura média), e analisar os núcleos das quasipartículas, classificando-os quanto à fase (hematita, magnetita, goethita e outros). Ademais, a rotina apresenta todos os dados já citados na forma de um relatório em pdf, que contém também uma listagem das quasipartículas e micropelotas em ordem crescente de tamanho. Essa rotina elimina a imprecisão e a subjetividade do operador humano, obtém medidas não realizáveis manualmente, permitindo prever características futuras do sínter de forma totalmente automática. / [en] The ores, once extracted, undergo several stages of processing before they can be properly used. The fines of ores that, at the end of this stage, do not have the granulometry required to feed the reduction furnaces, pass through agglomeration processes to reach it, such as pelletizing and sintering. The material produced in one of the stages of the latter process is the focus of this work. These fines first go through a micro-agglomeration stage, which is fundamental to the process because many of the characteristics and properties of the sinter are function of the structure of the pre-heat treatment microcluster. It consists of a mixture of the sinter feed, water, fluxes and solid fuel (coke). There are 3 typical structures for a microcluster: quasiparticle, micropellet, and non-agglomerated particles. The present dissertation has developed an automatic routine in the FIJI image-processing program, based on optical microscope image processing and analysis, which is able to identify the particles of different granulometry that compose the sample, and classify them in the 3 classes mentioned above. After classification, the routine is able to extract attributes of the identified objects (percentage of each class, average circularity, average thickness), and to analyze the quasiparticle nuclei, classifying them as to the phase (hematite, magnetite, goethite and others). In addition, the routine presents all the data in the form of a pdf report, which also contains a listing of quasiparticles and micropellets in increasing order of size. This automatic classification eliminates the lack of reproducibility and subjectivity of the human operator, provides measures that would be untenable manually, allowing the forecast of the future characteristics of the sinter in a fully automatic fashion.

Made available in DSpace on 2014-06-11T19:22:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-25Bitstream added on 2014-06-13T18:49:33Z : No. of bitstreams: 1 silva_jf_me_ilha.pdf: 1508098 bytes, checksum: a71768d52f587fb0eddda6d0c43e13e9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho é apresentado um sistema interativo para o processamento e armazenamento de imagens no domínio wavelet e uma interface para processamento de imagens digitais. A proposta apresentada baseia-se na transformada wavelet e em métodos de limiar. O sistema de armazenamento tem como objetivo a otimização do espaço computacional, tanto para armazenamento como para transmissão de imagens. Sendo para isso necessário a aplicação da Transformada Wavelet nas respectivas imagens e dos diversos métodos de limiar a serem escolhidos. Estas aplicações permitem extrair informações relevantes para o armazenamento de uma imagem com um menor custo computacional e com uma margem de erro muito pequena quando se compara as imagens, original e processada, ou seja, não há perda de qualidade ao aplicar o sistema de codificação apresentado. Os resultados obtidos a partir das informações extraídas das imagens são apresentados numa interface gráfica. É através da interface gráfica que o usuário usa os arquivos para visualizar e analisar os resultados dos programas diretamente na tela do computador sem a preocupação de lidar com os códigos fontes. A interface gráfica, os programas de processamento de imagens via Transformada Wavelet e os métodos de limiar foram desenvolvidos no ambiente do MATLAB, possibilitando uma troca direta de informações entre eles e o usuário. / In this work an interactive system processing and storage of compressed images in the wavelet domain, and an interface for digital image processing are presented. The storage method proposed is based on the wavelet transform and a threshold method. It has the objective of optimizing the computational space, for storage and for transmission of images. It is necessary first a pre-processing routine and after, the characterization through the application of the wavelet transform to the respective images and the several threshold methods to be chosen. These applications allow the extraction of relevant information for an image compression or storage image with a smaller computational cost and with a very small of error when the original and processed images are compared, in other words, there is no quality loss when applying the codification system presented. The results obtained from the extracted information of the images are presented in a graphic interface for image processing. The graphic interface, the programs for image processing using the wavelet transform and the thresholding methods were developed in a MATLAB environment, making possible a direct change of information between them and the user, without the concern of working with source codes. Through this graphic interface the user can use files which permits him visualize and analyze the results of the programs in the computer screen.

Orientador: Francisco Villarreal Alvarado / Banca: Jozué Vieira Filho / Banca: Pedro Henrique Cox / Resumo: Neste trabalho é apresentado um sistema interativo para o processamento e armazenamento de imagens no domínio wavelet e uma interface para processamento de imagens digitais. A proposta apresentada baseia-se na transformada wavelet e em métodos de limiar. O sistema de armazenamento tem como objetivo a otimização do espaço computacional, tanto para armazenamento como para transmissão de imagens. Sendo para isso necessário a aplicação da Transformada Wavelet nas respectivas imagens e dos diversos métodos de limiar a serem escolhidos. Estas aplicações permitem extrair informações relevantes para o armazenamento de uma imagem com um menor custo computacional e com uma margem de erro muito pequena quando se compara as imagens, original e processada, ou seja, não há perda de qualidade ao aplicar o sistema de codificação apresentado. Os resultados obtidos a partir das informações extraídas das imagens são apresentados numa interface gráfica. É através da interface gráfica que o usuário usa os arquivos para visualizar e analisar os resultados dos programas diretamente na tela do computador sem a preocupação de lidar com os códigos fontes. A interface gráfica, os programas de processamento de imagens via Transformada Wavelet e os métodos de limiar foram desenvolvidos no ambiente do MATLAB, possibilitando uma troca direta de informações entre eles e o usuário. / Abstract: In this work an interactive system processing and storage of compressed images in the wavelet domain, and an interface for digital image processing are presented. The storage method proposed is based on the wavelet transform and a threshold method. It has the objective of optimizing the computational space, for storage and for transmission of images. It is necessary first a pre-processing routine and after, the characterization through the application of the wavelet transform to the respective images and the several threshold methods to be chosen. These applications allow the extraction of relevant information for an image compression or storage image with a smaller computational cost and with a very small of error when the original and processed images are compared, in other words, there is no quality loss when applying the codification system presented. The results obtained from the extracted information of the images are presented in a graphic interface for image processing. The graphic interface, the programs for image processing using the wavelet transform and the thresholding methods were developed in a MATLAB environment, making possible a direct change of information between them and the user, without the concern of working with source codes. Through this graphic interface the user can use files which permits him visualize and analyze the results of the programs in the computer screen. / Mestre