Visual processing of form: evidences for angular narrow-band frequency channels in human / Processamento visual da forma: evidências para canais múltiplos de freqüências angulares em humanos

Abstract

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