Region- and edge-based configurational effects in texture segmentation.
We have found a new configurational effect in texture segmentation. In addition to collinear facilitation at the edge, this effect results from contextual modulation within the texture-region, i.e. from texels not abutting the segmented edge. The largest facilitation was found when two conditions were fulfilled: (i) elements along the edge were parallel to the edge and collinear, (ii) elements in the texture-region were also collinear but non-parallel to the edge. We show that this facilitation occurs when there are groups of different orientation from the edge in the texture-region. We suggest two possible underlying mechanisms: either a region-based process that links collinear iso-oriented elements and locates the edge when the orientation changes, or else second-order filters tuned to orientation differences rather than orientation per se.
Giora
Enrico
E
Department of General Psychology, University of Padua, Via Venezia 8, 35131-Padua, Italy. enrico.giora@unipd.it
Casco
Clara
C
D000328:Adult; D015350:Contrast Sensitivity; D004192:Discrimination, Psychological; D006801:Humans; D008960:Models, Psychological; D009949:Orientation; D010775:Photic Stimulation / Q000379:methods; D013997:Time Factors; D014796:Visual Perception