Measurements of the spectral modulation sensitivity function for two normal observers with CRT monitors

We have measured the sensitivity of the human visual system to chromatic stimuli of single chromatic frequency, ranging from 0.2 to 8.2 cycles/400 nm, and for eight initial phases from 0◦ to 315◦. The optimal phase curves obtained for two observers show a CSF-type shape, with minima at certain frequencies which did not appear in previous computational predictions. The implications of a value of the cut-off frequency of somewhat less than 8 cycles/400 nm are also discussed.