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dc.contributor.authorCunningham, Roberten_US
dc.contributor.authorBeck, Jacoben_US
dc.contributor.authorMingolla, Ennioen_US
dc.date.accessioned2011-11-14T19:07:58Z
dc.date.available2011-11-14T19:07:58Z
dc.date.issued1998-12en_US
dc.identifier.urihttp://hdl.handle.net/2144/2368
dc.description.abstractVisual search is extended from the domain of polygonal figures presented on a uniform field to photo-realistic scenes containing target objects in dense, naturalistic backgrounds. The target in a trial is a computer-rendered rock protruding in depth from a "wall" of rocks of roughly similar size but different shapes. Subjects responded "present" when one rock appeared closer than the rest, owing to occlusions or cast shadows, and "absent" when all rocks appeared to be at the same depth. Results showed that cast shadows can significantly decrease reaction times compared to scenes with no cast shadows, in which the target was revealed only by occlusions of rocks behind it. A control experiment showed that cast shadows can be utilized even for displays involving rocks of several achromatic surface colors (dark through light), in which the shadow cast by the target rock was not the darkest region in the scene. Finally, in contrast with reports of experiments by others involving polygonal figures, we found no evidence for an effect of illumination direction (above vs. below) on search times.en_US
dc.description.sponsorshipOffice of Naval Research (N00014-94-1-0597, N00014-95-1-0409)en_US
dc.language.isoen_USen_US
dc.publisherBoston University Center for Adaptive Systems and Department of Cognitive and Neural Systemsen_US
dc.relation.ispartofseriesBUCAS/CNS Technical Reports; BUCAS/CNS-TR-1998-034en_US
dc.rightsCopyright 1998 Boston University. Permission to copy without fee all or part of this material is granted provided that: 1. The copies are not made or distributed for direct commercial advantage; 2. the report title, author, document number, and release date appear, and notice is given that copying is by permission of BOSTON UNIVERSITY TRUSTEES. To copy otherwise, or to republish, requires a fee and / or special permission.en_US
dc.subjectVisual searchen_US
dc.subjectShadingen_US
dc.subjectShadowsen_US
dc.subjectCast shadowsen_US
dc.subjectIllumination directionen_US
dc.subjectPhoto-realistic renderingen_US
dc.subjectNaturalistic sceneen_US
dc.subjectSearch asymetriesen_US
dc.titlePhoto-Realistic Scenes with Cast Shadows Show No Above/Below Search Asymmetries for Illumination Directionen_US
dc.typeTechnical Reporten_US
dc.rights.holderBoston University Trusteesen_US


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