T-junctions, apparent depth, and perceived lightness contrast.
Observers performed lightness matches for physically equivalent gray targets of a simultaneous lightness contrast display and displays in which both targets were on the same background. Targets either shared a common line-texture pattern with their respective backgrounds or did not. Results indicate that when targets share a line-texture pattern with their respective backgrounds, a contrast effect is obtained. However, when the target's pattern is different than the background's pattern, perceived contrast is significantly reduced and the target appears as a separate 3-D entity. This result applies to both vertically and horizontally oriented displays, to targets that are increments or decrements, and to line-texture patterns that are black or white. Line patterns that are shared by targets and backgrounds result in T-junctions that provide occlusion information. We conclude that targets and backgrounds perceived to be on separate planes because of T-junctions are less likely to be perceptually grouped together and that their luminance values are less likely to be compared with one another.
Bonato
Frederick
F
Department of Psychology, Saint Peter's College, Jersey City, New Jersey 07306, USA. bonato_f@spc.edu
Cataliotti
Joseph
J
Manente
Melissa
M
Delnero
Karen
K
D015350:Contrast Sensitivity; D003867:Depth Perception; D006801:Humans; D008027:Light; D009903:Optical Illusions; D010364:Pattern Recognition, Visual