Measurements of contrast sensitivity for peripheral vision.

Contrast detection thresholds were measured for the eccentricities from 0° to 27° and a range of stimuli frequencies from 0.125cpd to 16cpd. The measurements were motivated by the need to collect visual performance data for the gaze-contingent rendering system. For this application, the mixed chromatic and achromatic stimuli are even more important than purely chromatic cases. Therefore, the detection of sine-gratings with Gaussian patches was measured for four mixed chromatic/achromatic with a varying share of the achromatic components. To verify that our experimental setup generates the results consistent with the previous work, we also measured the contrast thresholds for achromatic (black to white) stimulus. Five observers participated in the experiments and they individually determined the detection threshold for each stimulus using the QUEST method. The results plotted as the contrast sensitivity function (CSF) follow the state-of-the-art CSF models. However, we report lower sensitivity to contrast for achromatic stimuli caused by the small size of the stimulus. The color directions closer to the chromatic green-to-red axis show higher contrast sensitivity in comparison to achromatic stimuli, while for the yellow-to-blue axis the sensitivity is lower. The higher achromatic component in the mixed stimuli approaches contrast sensitivity to the achromatic CSF.