Psicologia: Reflexão e Crítica
Print version ISSN 0102-7972
SANTOS, Natanael Antonio dos; NOGUEIRA, Renata Maria Toscano Barreto Lyra and SIMAS, Maria Lúcia de Bustamante. Visual processing of form: evidences for angular narrow-band frequency channels in humans. Psicol. Reflex. Crit. [online]. 2005, vol.18, n.1, pp. 98-103. ISSN 0102-7972. http://dx.doi.org/10.1590/S0102-79722005000100013.
The aim of this work was to characterize and to compare the response curves of the human visual system for angular filters of 1 and 4 cycles/360º defined in polar coordinates. We measured 15 curves for each filter with 5 adult volunteers using a supra-threshold summation method with a forced-choice paradigm. The results showed maximum summation effects at test frequencies for angular (1 and 4 cycles/360º) filters surrounded on both sides by strong inhibition. These results were in agreement with the existence of channels or narrow-band angular filters operating in the human visual system either through summation or inhibition of specific frequency ranges.
Keywords : Visual processing of form; angular frequency; narrow-band frequency filters; supra-threshold summation method.