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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

Solu??o do problema inverso da tomografia por imped?ncia el?trica utilizando o simulated annealing : uma nova abordagem / Image reconstruction using simulated annealing in electrical impedance tomography: a new approach

Martins, Jefferson Santana 26 January 2016 (has links)
Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-04-27T17:29:27Z No. of bitstreams: 1 TES_JEFFERSON_SANTANA_MARTINS_COMPLETO.pdf: 2903533 bytes, checksum: 3856ba9ee2be72e3002b673e81e63fd4 (MD5) / Made available in DSpace on 2016-04-27T17:29:27Z (GMT). No. of bitstreams: 1 TES_JEFFERSON_SANTANA_MARTINS_COMPLETO.pdf: 2903533 bytes, checksum: 3856ba9ee2be72e3002b673e81e63fd4 (MD5) Previous issue date: 2016-01-26 / Image reconstruction in electrical impedance tomography (EIT) deals with an ill-posed and nonlinear inverse problem. It intends to minimize the difference between simulated (virtual) object data and data from a non simulated (real) object. In this paper, a new approach to the Simulated Annealing method applied to reconstruction of EIT images is described. The main advantage in this approach is that all conductivity parameters are updated simultaneously. Other methods that employ Simulated Annealing to the problem of EIT evaluate each conductivity parameter individually resulting in high computational cost. The algorithm was tested both with computationally generated data and with measurements performed on a physical simulation tank. In both cases, the method was able to make data inversion, determining the position, the dimensions and the conductivity of materials in an opaque object plane. / O problema de reconstru??o da tomografia por imped?ncia el?trica (TIE) ? um problema de otimiza??o inverso, n?o linear e mal-condicionado, no qual se objetiva minimizar a diferen?a entre dados medidos e calculados atrav?s de um modelo num?rico. No presente trabalho, ? descrita uma nova abordagem do m?todo de recozimento simulado aplicado ? reconstru??o de imagens de TIE. A principal vantagem do algoritmo apresentado ? que todos os par?metros de condutividade do dom?nio s?o atualizados conjuntamente. Outros m?todos que empregam o recozimento simulado para a solu??o do problema da TIE avaliam individualmente cada par?metro de condutividade, tendo, por isso, grande custo computacional. O m?todo proposto foi testado com dados gerados computacionalmente e com medidas realizadas em um tanque de simula??o f?sica. Em ambos os casos, ele p?de fazer a invers?o dos dados, sendo capaz de determinar a posi??o, as dimens?es e a condutividade de diferentes materiais em um plano transverso de um objeto opaco.

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