| Abstract: | It was shown that human contrast sensitivity function (CSF) had noticeable extremums (Evseev et al, 1987). This phenomenon has not been closely investigated yet. In present paper, we studied human CSFs that were obtained by using gratings with 0 degrees, 90 degrees and 135 degrees orientations. It has been shown that, firstly, periodic extremums are clearly visible in averaged CSF obtained by using 0 degrees orientation gratings but they are weakly evident when 90 degrees and 135 degrees gratings were used. Secondly, the extremum amplitudes dramatically decrease in repeated testing, and virtually disappear after the 5th one. The data obtained suggest that local extremums phenomenon is related to mirror visual system information processing rather than subject's casual mistakes. |
