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Provedor de dados:  56
País:  Brazil
Título:  Contrast sensitivity to radial frequencies modulated by Jn and j n Bessel profiles
Autores:  Simas,M.L.B.
Santos,N.A.
Data:  2002-11-01
Ano:  2002
Palavras-chave:  Spatial frequency
Angular frequency
Polar gratings
Face perception
Contrast sensitivity
Resumo:  We measured human contrast sensitivity to radial frequencies modulated by cylindrical (Jo) and spherical (j o) Bessel profiles. We also measured responses to profiles of j o, j1, j2, j4, j8, and j16. Functions were measured three times by at least three of eight observers using a forced-choice method. The results conform to our expectations that sensitivity would be higher for cylindrical profiles. We also observed that contrast sensitivity is increased with the j n order for n greater than zero, having distinct orderly effects at the low and high frequency ends. For n = 0, 1, 2, and 4 sensitivity tended to occur around 0.8-1.0 cpd while for n = 8 and 16 it seemed to shift gradually to 0.8-3.0 cpd. We interpret these results as being consistent with the possibility that spatial frequency processing by the human visual system can be defined a priori in terms of polar coordinates and discuss its application to study face perception.
Tipo:  Info:eu-repo/semantics/article
Idioma:  Inglês
Identificador:  http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002001100014
Editor:  Associação Brasileira de Divulgação Científica
Relação:  10.1590/S0100-879X2002001100014
Formato:  text/html
Fonte:  Brazilian Journal of Medical and Biological Research v.35 n.11 2002
Direitos:  info:eu-repo/semantics/openAccess
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