The sensitivity of the peripheral visual system to amplitude-modulation and frequency-modulation of sine-wave patterns

Abstract

The detectability of amplitude modulation and spatial frequency modulation of suprathreshold sine-wave gratings was measured at retinal eccentricities ranging from 0 to 30 deg. The main conclusions to be drawn from the experimental results are: (1) for this visual task it is not possible to bring peripheral sensitivity to the same level as foveal sensitivity by scaling the stimuli with the inverse of the cortical magnification factor M. (2) Increasing the number of cycles in the carrier grating improves modulation detectability. For gratings in the periphery this holds up to the largest stimulus size used (64 cycles). In earlier investigations it has been shown that for central vision the improvement ends at about 16 cycles.