We found that a moving target line, more-vertical than 45 deg-oriented background lines, pops-out (d'=1.2) although it moves at the same speed of background elements and although it is invisible in static presentation (d'=.7). We suggest that the moving more-vertical target is more salient because the motion system responds to the orthogonal-velocity-component (V(perpendicular)=Delta d/Delta t sin theta) that is larger for the more-vertical target than for distracters. However, motion does not produce high d' when the target is more horizontal than background (d'=.6). This result is not expected if saliency resulted from the sum of saliency of orientation and motion independently coded but is instead predicted by visual search asymmetry. A line length effect on the moving target saliency also suggests that V(perpendicular) is extracted on the whole line and this operation is facilitated by line length in the same way for more-vertical and more-horizontal targets. Altogether, these results demonstrate that speed-based segmentation operating on V(perpendicular) not only affects speed and direction of motion discrimination, as previously demonstrated, but accounts for high saliency of image features that would otherwise prove undetectable of the basis of orientation-contrast

Casco, C., Grieco, A., Giora, E., Martinelli, M. (2006). Saliency from orthogonal velocity component in texture segregation. VISION RESEARCH, 46(6-7), 1091-1098 [10.1016/j.visres.2005.09.032].

Saliency from orthogonal velocity component in texture segregation

GIORA, ENRICO;
2006

Abstract

We found that a moving target line, more-vertical than 45 deg-oriented background lines, pops-out (d'=1.2) although it moves at the same speed of background elements and although it is invisible in static presentation (d'=.7). We suggest that the moving more-vertical target is more salient because the motion system responds to the orthogonal-velocity-component (V(perpendicular)=Delta d/Delta t sin theta) that is larger for the more-vertical target than for distracters. However, motion does not produce high d' when the target is more horizontal than background (d'=.6). This result is not expected if saliency resulted from the sum of saliency of orientation and motion independently coded but is instead predicted by visual search asymmetry. A line length effect on the moving target saliency also suggests that V(perpendicular) is extracted on the whole line and this operation is facilitated by line length in the same way for more-vertical and more-horizontal targets. Altogether, these results demonstrate that speed-based segmentation operating on V(perpendicular) not only affects speed and direction of motion discrimination, as previously demonstrated, but accounts for high saliency of image features that would otherwise prove undetectable of the basis of orientation-contrast
Articolo in rivista - Articolo scientifico
Psychophysics; Photic Stimulation; Pattern Recognition, Visual; Field Dependence-Independence; Discrimination (Psychology); Motion Perception; Orientation; Humans
English
2006
46
6-7
1091
1098
none
Casco, C., Grieco, A., Giora, E., Martinelli, M. (2006). Saliency from orthogonal velocity component in texture segregation. VISION RESEARCH, 46(6-7), 1091-1098 [10.1016/j.visres.2005.09.032].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/21251
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