Mapping features from natural scenes.

Intensity (brightness) on the top-down map (B) reflects saliency of perceptual object representation within the original scene [5, 6] (A), while the bottom-up map (C) indicates edge energy content [3, 7]. We identify 4 locations that are rich/poor on the top-down map (green/red circles in B) and/or rich/poor on the bottom-up map (solid/dashed circles in C); the two locations indicated by dashed-green and solid-red circles in D are rich on one map and poor on the other. An oriented wavelet is inserted at one location in congruent (E) or incongruent (F) configuration, orientation noise is added [8] (G), and observers must determine whether probe is congruent or not [9, 10].