• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Automatická detekce výpadku ve vrstvě nervových vláken / Automatic detection of neural fibers losses

Václavek, Martin January 2010 (has links)
This work is focused on detection of loss in nerve fibre layer on colour pictures of retina, witch are makes by fundus camera. It describe every simple objects of retina, optic nerve head, macula lutea and vascular bed. It detect optic nerve head and his near area, witch is general for detection of breakdownds. It use several metodes of picture adjusting for picture elaboration and objects detection (segmentation, thresholding, enhancement, hough transformation ). The detection of loss in nerve fibre layer is based on comparing of statistic parameters ( average, standart deviation, skewness coefficient and kurtosis coefficient histogram, entropy ) in choosed areas with and withou destruction of nerve layers. Vascular bed have badwatsh on results, cause of this we using hand choosing of essay.
2

Influência da aplicação de diferentes filtros no diagnóstico de alterações ósseas da articulação temporomandibular em exames de tomografia computadorizada de feixe cônico / Influence of Cone-Beam computed tomography enhancement filters on diagnosis of morphological temporomandibular joint changes

Verner, Francielle Silvestre 27 February 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-27T12:24:58Z No. of bitstreams: 1 franciellesilvestreverner.pdf: 1911397 bytes, checksum: 9ee39372ad372741eb873b6f4284efa0 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-28T13:03:16Z (GMT) No. of bitstreams: 1 franciellesilvestreverner.pdf: 1911397 bytes, checksum: 9ee39372ad372741eb873b6f4284efa0 (MD5) / Made available in DSpace on 2016-06-28T13:03:16Z (GMT). No. of bitstreams: 1 franciellesilvestreverner.pdf: 1911397 bytes, checksum: 9ee39372ad372741eb873b6f4284efa0 (MD5) Previous issue date: 2012-02-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A articulação temporomandibular (ATM) pode ser acometida por alterações em sua superfície óssea, exibindo graus diferentes de remodelação, aplainamento condilar, osteófitos, erosão e esclerose óssea, que podem estar associadas ao desenvolvimento de desordens mecânicas e dores na região das articulações. O exame por imagem é determinante no diagnóstico final e estabelecimento de um correto plano de tratamento. Dentre os métodos por imagem, destaca-se a tomografia computadorizada de feixe cônico (TCFC) que permite uma visualização das ATM sem sobreposição das estruturas contra laterais. Ferramentas disponibilizadas pelos softwares dos aparelhos de TCFC parecem otimizar o diagnóstico. O filtro é a ferramenta capaz de transformar a imagem de acordo com a estrutura que se pretende avaliar, com o objetivo de aumentar a acurácia do exame. O presente estudo avaliou a influência da aplicação de diferentes filtros no diagnóstico de alterações morfológicas das ATM. Foram analisadas imagens de TCFC de 100 ATM. A partir das imagens originais (sem filtro), foram aplicados quatro filtros (Sharpen, Angio_Shapen_Low 3x3, Smooth, Angio_Sharpen_High 5x5), totalizando 500 imagens. Cada imagem foi classificada quanto ao diagnóstico e quanto à qualidade geral da imagem, por dois especialistas em Radiologia Odontológica. Foram calculados os valores de sensibilidade, especificidade, acurácia, preditivo positivo e preditivo negativo para cada condição, em cada um dos filtros testados, e comparou-se os filtros por meio do teste de Cochran. A qualidade da imagem de cada filtro foi comparada através do teste de Friedman. Os valores de sensibilidade, especificidade, acurácia, preditivos positivo e negativo variaram discretamente. Apenas o filtro Angio_Sharpen_High 5x5 influenciou de forma significante o diagnóstico para a condição esclerose da eminência articular (P<0,05). Os filtros não influenciaram de forma significante o diagnóstico de alterações ósseas das ATM, porém os filtros Sharpen e Angio_Sharpen_Low 3x3 apresentaram maior frequência de imagens com ótimas condições de diagnóstico, tornando-se uma alternativa para o diagnóstico de alterações ósseas das superfícies articulares. / A variety of morphological changes in the bone of the mandibular condyle and articular eminence can occur in patients with tempormandibular joint disosders (TMD). Changes include flattening, osteophytes, erosions and sclerosis. Radiographic examination is an essential component of diagnostic evaluation of temporomandibular joint (TMJ). Currently cone-beam computed tomography (CBCT) has been widely used to evaluate TMJ. Many CBCT softwares has been designed to enhance images. Filters are a tool used to minimize image noise using mathematical algorithms to reduce or increase specific characteristics. The aim of this study was to determine if CBCT enhancement filters influence the diagnosis of morphological TMJ changes. Images of 100 TMJ were examined. All images were analyzed without filter application and with de following filters for XoranCat® software: Sharpen, Angio_Shapen_Low 3x3, Smooth e Angio_Sharpen_High 5x5. Each image were examined by two oral radiologists who classified them for the presence of morphological changes and for the image quality. Sensibility, specificity, accuracy, positive predictive value and negative predictive value were calculated for each filter in each condition. Cochran test was used to evaluate all images versus the original images, and Friedman test was used to evaluate the quality of image between all filters. Sensibility, specificity, accuracy, positive predictive value and negative predictive value had little variability. Only Angio_Sharpen_High 5x5 filter had influenced the diagnosis of sclerosis in the articular eminence (P<0,05). In general, filters didn`t influence the diagnosis of morphological changes of TMJ, but Sharpen and Angio_Sharpen_Low 3x3 filters were classified as excellent image quality, and became an alternative to diagnosis of TMJ changes.

Page generated in 0.1019 seconds