MEASUREMENTS OF SENSITIVITY TO SIMULATED CHROMATIC FREQUENCIES FOR NORMAL AND DICHROMATIC OBSERVERS

In recent years, the study of the human colour vision system in the ch romatic-frequency domain has been a source of interesting results, con cerning especially the spectral modulation sensitivity function (SMSF) . Here, we present a detailed study of the mid-frequency range of this function for two normal observers and also the SMSF for two observers with colour-vision deficiencies (protanopes). The measurements have b een obtained by simulating stimuli of sinusoidal spectral power distri bution. Observers viewed metamers of these stimuli which were generate d on a CRT monitor. The minimum found at 1.6 c/400 nm for normal obser vers is confirmed and some explanation is attempted by the calculation of the Fourier transform of the spectral response of colour-vision me chanisms. The results for dichromatic observers show a general toss of sensitivity with respect to the normal subjects, especially at certai n frequencies.