• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Master's Dissertation
DOI
https://doi.org/10.11606/D.59.2008.tde-11092013-112028
Document
Author
Full name
Lina Maria Perilla Rodriguez
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2008
Supervisor
Committee
Fukusima, Sergio Sheiji (President)
Ben, Cristina Marta Del
Galera, Cesar Alexis
Title in Portuguese
Efeitos de bandas de frequência espacial alta e baixa no reconhecimento de faces em campo visual lateralizado
Keywords in Portuguese
Assimetria Cerebral
Bandas de Frequência Espacial.
Reconhecimento de faces
Abstract in Portuguese
O presente trabalho teve por objetivo pesquisar os efeitos que as bandas de freqüência espacial alta e baixa têm no reconhecimento de faces em campo visual lateralizado. Foram distribuídos aleatoriamente 40 participantes em dois grupos. Os voluntários observaram 14 fotos de faces sem filtragem até memorizá-las. A seguir foram apresentadas 56 fotos de faces com filtragens de freqüências espaciais, intercaladas aleatoriamente com apresentações de faces não mostradas anteriormente. Cada uma delas foi exibida na tela durante 300 ms mediante a metodologia de apresentação dicótica. O participante devia responder se a face mostrada pertencia ao grupo de fotos inicialmente observado. As freqüências de respostas permitiram calcular as curvas ROC (Receiver Operating Characteristic) e os parâmetros Az e da preconizado pela Teoria de Detecção de Sinal (MACMILLAN; CREELMAN, 2005) para as faces naturais, faces compostas de freqüências espaciais baixas e faces compostas de freqüências espaciais altas. Os resultados obtidos mostram que as faces Originais foram melhor reconhecidas do que as faces com Freqüências Espaciais Altas (FEA) ou Freqüências Espaciais Baixas (FEB). Ao contrário do achado na literatura, o Hemisfério Esquerdo (HE) teve uma tendência a reconhecer mais eficazmente as faces do que o Hemisfério Direito (HD), independente da condição de filtragem. O HD é igualmente competente do que o HE para processar FEB, mas pior do que o HE para processar FEA. Quanto à performance por gênero, tanto homens quanto mulheres tiveram um desempenho similar quando as faces foram processadas com o HD. O desempenho das mulheres ficou de acordo com a hipótese da FE, pois o reconhecimento que fizeram para as faces com FEA foi melhor do que para as que tinham predomínio de FEB. Os homens, mesmo com o HE, fizeram um reconhecimento melhor das faces com predomínio de FEB do que das faces com FEA.
Title in English
Effects of high and low spatial frequency bands in face recognition in lateralized visual field.
Keywords in English
Cerebral Asymmetry
Face Recognition
Spatial Frequency Bands.
Abstract in English
This study was made with the objective of investigate the effects of high and low spatial frequency bands in face recognition in lateralized visual field. 40 participants were randomly distributed in two groups. The volunteers viewed fourteen non-filtered pictures of faces until they managed to memorize them. After that, fifty six spatial frequency filtered pictures of faces were presented randomly interspersed with pictures of faces previously showed. Each one of them was exhibited in the screen for three hundred milliseconds using the dichotic presentation procedure. The participant should answer whether the face presented belonged to the group of pictures initially viewed. The frequency of responses allowed to calculate the ROC (Receiver Operating Characteristic) Curves and the Az and da parameters praised by the Signal Detection Theory (Macmillan; Creelman, 2005) for natural faces, low spatial frequency composed faces and high spatial frequency composed faces. Results showed that original faces were better recognized than faces with high spatial frequencies (HSF) and low spatial frequencies (LSF). Differently from literature, the left hemisphere was more accurate than the right to recognize faces, regardless of the filter condition. The RH was equivalent to the LH to process LSF, but worse than the LH to process HSF. Concerning the performance of the genders, men and women judged faces in a very similar way when they used the RH. The performance of women agreed with the FE hypothesis, being faces with HSF recognized better than faces with LSF. Men, even using the LH, were more accurate to recognize faces with LSF than HSF.
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
Dissertacaofinal.pdf (1.01 Mbytes)
Publishing Date
2014-02-20
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2024. All rights reserved.