The contrast sensitivity of human colour vision to red‐green and blue‐yellow chromatic gratings.

Abstract

SUMMARY1. A method ofproducing red-green and blue-yellow sinusoidal chromatic gratings is used which permits the correction of all chromatic aberrations.2. A quantitative criterion is adopted to choose the intensity match of the two colours in the stimulus: this is the intensity ratio at which contrast sensitivity for the chromatic grating differs most from the contrast sensitivity for a monochromatic luminance grating. Results show that this intensity match varies with spatial frequency and does not necessarily correspond to a luminance match between the colours.3. Contrast sensitivities to the chromatic gratings at the criterion intensity match are measured as a function of spatial frequency, using field sizes ranging from 2 to 23 deg. Both blue-yellow and red-green contrast sensitivity functions have similar low-pass characteristics, with no low-frequency attenuation even at low frequencies below 041 cycles/deg. These functions indicate that the limiting acuities based on red-green and blue-yellow colour discriminations are similar at 11 or 12 cycles/deg.4. Comparisons between contrast sensitivity functions for the chromatic and monochromatic gratings are made at the same mean luminances. Results show that, at low spatial frequencies below 0 5 cycles/deg, contrast sensitivity is greater to the chromatic gratings, consisting of two monochromatic gratings added in antiphase, than to either monochromatic grating alone. Above 0-5 cycles/deg, contrast sensitivity is greater to monochromatic than to chromatic gratings.

Detecting and discriminating the direction of motion of luminance and colour gratings

“…The extent of the difference will depend on the relative degree of summation in colour receptive fields, and in the input stages of motion-detecting sub-units. Since both the spatial (Mullen, 1985) and the temporal (de Lange, 1958) sensitivity of colour detection mechanisms are low-pass we might expect a substantial degree of summation, and so a substantial enhancement in sensitivity for detection tasks over direction discrimination.…”

Towards an independent brain–computer interface using steady state visual evoked potentials

“…Therefore, this form of stimulus should work with subjects who have impaired color vision. However, color may affect results with different SSVEP displays (Mullen, 1985;Regan, 1989;Arakawa et al, 1999).…”

Diagnostic Colors Mediate Scene Recognition

“…Even if it has been observed that pictures of natural scenes do have color information represented in medium to high spatial frequencies (Parraga et al, 1998), the visual system tends to perceive chromatic information at coarser scales better than luminance information (Mullen, 1985). 7 The reported effects of color should therefore arise from the spatial layout of crude color information.…”