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. 2013 Mar 26;13(4):21. doi: 10.1167/13.4.21

Figure 2.

Figure 2

Psychometric functions for individual image statistics that carry orientation information. (A) Second-order correlations in cardinal (β_, β|) and oblique directions (β\, β/) directions. For each statistic, psychometric functions are shown for negative excursions (left element of each pair) and positive excursions (right element of each pair). Chance performance is 0.25. The patches above the psychometric functions show typical 32 × 32 samples of images defined by the corresponding second-order statistic, constructed with β = ±0.4. For second-order statistics, positive values correspond to correlation in one direction; negative values correspond to anticorrelation in that direction. (B) Third-order correlations in each of three directions (θ⌋, θ⌊, θ⌈). Psychometric functions as in (A). The image samples are constructed with θ = ±0.72. For third-order statistics, positive values correspond to an excess of white triangular patches in a particular orientation; negative values correspond to an excess of dark triangular patches in the same orientation. Data from two representative subjects, MC and DT, out of N = 6.