title: Cast shadows in wide perspective.
abstract: We investigated the apparent spatial layout of cast shadows up to very wide fields of view. We presented up to 130 degrees wide images in which two 'flat poles' were standing on a green lawn under a cloudless blue sky on a sunny day. The poles threw sharp cast shadows on the green, of which one was fixed. The observer's task was to adjust the azimuth of the shadow of the other pole such that it fitted the scene. The source elevation was kept constant. The two cast shadows are, of course, parallel in physical space, but generically not in the picture plane because of the wide perspective. We found that observers made huge systematic errors, indicating that, generically, they fail to account for these perspective effects. The systematic deviations could be well described by a weighted linear combination of the directions in the picture plane and in the physical space, with weights that depended on the positions of, and distance between, the poles.
authors: Perceptual Intelligence Laboratory (pi-lab), Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628 CE Delft, The Netherlands. s.c.pont@tudelft.nl
authors: Sylvia C
authors: SC
authors: Pont
authors: Maarten W A
authors: MW
authors: Wijntjes
authors: Augustinus H J
authors: AH
authors: Oomes
authors: Andrea
authors: A
authors: van Doom
authors: Onno
authors: O
authors: van Nierop
authors: Huib
authors: H
authors: de Ridder
authors: Jan J
authors: JJ
authors: Koenderink
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009949:Orientation; D011581:Psychological Tests; D012815:Signal Processing, Computer-Assisted; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult