TitleSpatial and photometric factors modulating the effect of depth on lightness
NameRadonjić, Ana (author), Gilchrist, Alan (chair), Shiffrar, Maggie (internal member), Van de Walle, Gretchen (internal member), Brainard, David (outside member), Rutgers University, Graduate School - Newark,
DescriptionAccording to the coplanar ratio principle (CRP), when the luminance range in the image is larger than 30:1 the lightness of a target surface depends on the luminance ratio between that target and its adjacent, coplanar neighbor. This conclusion was based on experiments (Gilchrist, 1977) using a dihedral corner display in which a change in the perceived spatial position of a target produced large changes in its perceived lightness, with no significant change in the observer’s retinal image. Using variations of this dihedral display, a series of experiments was conducted to test a group of conflicting claims made by CRP, the anchoring theory (Gilchrist et al., 1999) and other writers (e.g. Kardos, 1934, Howe, 2006) concerning the role of coplanarity, adjacency, surroundedness, articulation, and luminance range.
Generally consistent with the predictions of the anchoring theory, the results show the following: (1) Articulation can substantially increase the depth effect. (2) Target lightness depends, not simply on its adjacent coplanar luminance, but on the highest luminance in its plane, irrespective of its position relative to the target. (3) When two or more levels of illumination are present on a plane, target lightness depends on the highest luminance in its framework of illumination, not on the highest luminance in its plane. (4) The size of the depth effect depends on the luminance ratio between the highest luminance values in the two planes, not on the overall luminance range across the planes. Thus strong depth effects can be obtained with a luminance range no greater than 30:1. (5) Surface continuity within a plane is necessary for the operation of coplanar ratios, although surroundedness can partially substitute for continuity, but only within the brightly illuminated plane.
NoteIncludes bibliographical references (p. 155-166)
Noteby Ana Radonjić
CollectionGraduate School - Newark Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work