Contrast sensitivity to radial frequencies modulated by Jn and jn Bessel profiles.
We measured human contrast sensitivity to radial frequencies modulated by cylindrical (Jo) and spherical (jo) Bessel profiles. We also measured responses to profiles of jo, 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.
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ML
Laboratório de Percepção Visual, Departamento de Psicologia, Universidade Federal de Pernambuco, Recife, PE, Brasil. mlbs@ufpe.br
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D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D010775:Photic Stimulation / Q000379:methods*; D012684:Sensory Thresholds / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology