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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Abordagem wavelet para detecÃÃo de cantos em formas / Wavelet boarding for detention of corners in forms

IÃlis Cavalcante de Paula JÃnior 26 March 2007 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A anÃlise de formas representa um papel importante em aplicaÃÃes de visÃo computacional e processamento de imagens, e a representaÃÃo da forma à o primeiro passo para esta anÃlise. Esta presente dissertaÃÃo discute e aborda um conjunto de tÃcnicas disponÃveis na literatura para a geraÃÃo de uma representaÃÃo adequada de formas baseada em cantos. A abordagem proposta provà uma decomposiÃÃo wavelet nÃo-decimada do contorno representado pelo sinal de angulaÃÃo e curvatura afim de representar uma forma por seus pontos mais relevantes sem requerer intervenÃÃo do usuÃrio. A metodologia adotada apresenta resultados promissores, faz uso de ferramentas disponÃveis na literatura e elimina caracterÃsticas redundantes da forma com o intuito de alcanÃar uma representaÃÃo que mantenha uma reconstruÃÃo adequada da forma original. Uma nova medida de avaliaÃÃo, sob o aspecto do erro obtido na reconstruÃÃo, tambÃm à apresentada de modo a confirmar que o algoritmo proposto realiza com sucesso a sua meta e supera os detectores de cantos utilizados para testes e comparaÃÃes. / Shape analysis plays an important role in computer vision and image processing applications and shape representation is the first step towards it. The current dissertation discusses a set of techniques available in the literature in order to generate an adequate shape representation based on corners. The proposed approach provides an non-decimated wavelet decomposition of the represented contour by curvature and angulation signals in order to represent the shape using the most relevant contour points without requiring any user intervention. The adopted methodology presents promising results and it uses a set of tools, with little highlight in the literature, and it eliminates the redundant shape features in order to accomplish the suitable representation of the original shape. A novel evaluation measure, concerning the reconstruction error, is also presented to confirm that the proposed algorithm achieves its goal and outperforms other corner detectors used for tests and comparison.

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