Psicologia: Reflexão e Crítica
On-line version ISSN 1678-7153
SANTOS, Natanael Antonio dos and SIMAS, Maria Lúcia de Bustamante. Perception and visual processing of form in humans: radial frequency filters of 1 and 4 cpd. Psicol. Reflex. Crit. [online]. 2002, vol.15, n.2, pp. 383-391. ISSN 1678-7153. http://dx.doi.org/10.1590/S0102-79722002000200015.
The aim of this work was to measure narrow-band frequency response curves for two radial frequency filters, spatial stimuli modulated by cylindrical Bessel profiles, J0, whose test frequencies were 1 and 4 cpd. Five humans observers with normal or corrected visual acuity measured 15 curves for each filter with a supra-threshold response summation psychophysics method allied within a forced-choice paradigm. The results showed maximum summation effects at test frequency for filters 1 and 4 cpd surrounded on both sides by strong inhibition. These results are consistent with the existence of narrow-band radial frequency filters operating in human visual system either through summation or inhibition of specific frequency ranges.
Keywords : Visual processing of form; radial frequency filter; radial frequency; supra-threshold summation method.