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Psicologia: Reflexão e Crítica
On-line version ISSN 1678-7153
SANTOS, Natanael Antonio dos; SIMAS, Maria Lúcia de Bustamante and NOGUEIRA, Renata Maria Toscano Barreto Lyra. Visual contrast perception in human beings: psychophysical evidence for high angular frequency channels. Psicol. Reflex. Crit. [online]. 2007, vol.20, n.1, pp. 26-34. ISSN 1678-7153. http://dx.doi.org/10.1590/S0102-79722007000100005.
The aim of this study was to measure narrow-band frequency response curves for four angular frequency filters. The test frequencies were 32, 48, 64 and 96 cycles/360º. Six humans observers with normal or corrected visual acuity measured nine curves for each filter, with a supra-threshold response summation psychophysical method allied with a forced-choice method. The results showed maximum summation effects at test frequency for filter frequencies 32, 48, 64 and 96 cycles/360º, as well as a strong inhibition for neighboring frequencies. These results are consistent with the existence of narrow-band angular frequency filters in the human visual system either through summation or the inhibition of specific high angular frequency ranges.
Keywords : Visual perception of form; angular frequency filter; angular frequency; supra-threshold summation method.