PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 10485128

Differences in lightness in achromatic transparency.

S C Masin·M Tommasi
View original source ↗Export metadata ↓

Abstract

It is presently unresolved whether lightnesses or differences in lightness are appropriate independent variables for models of perceived achromatic transparency. This experiment shows that differences in lightness rather than lightnesses affected the rated transparency and that local changes in differences in lightness altered the rated transparency locally. These results indicate that models of the perceived degree of transparency should be separately formulated for the different parts of a transparent surface and for the whole transparent surface. Two new models of the combined effects of lightness differences on the perceived transparency are proposed.

Explore related subjects

Form PerceptionHumansLightMathematicsModels, PsychologicalVisual PerceptionJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S C Masin, M Tommasi. 1999. Differences in lightness in achromatic transparency.. https://doi.org/10.2466/pms.1999.88.3c.1385

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2003

Visual perception: shaping what we see.

A new psychophysical study has examined the free flow of perception as observers viewed stimuli with several possible visual interpretations. The results suggest that our subjective impression of such ambiguous patterns may be more closely linked to the brain's encoding of complex shape than previously appreciated.

Form Perception↗
PubMed2003

The shape of holes.

The shape of holes can be recognized as accurately as the shape of objects (Palmer, S. E. (1999). Vision science: photons to phenomenology. Cambridge, MA: MIT Press), yet the area enclosed by a hole is a background region, and it can be demonstrated that background regions are not represented as having shape. What is therefore the shape of a hole, if any? To resolve this apparent paradox, we suggest that the shape of a hole is available indirectly from the shape of the surrounding object. We exploited the fact that observers are faster at judging the position of convex vertices than concave ones (Perception 30 (2001) 1295), and using a figural manipulation of figure/ground we found a reversal of the relative speeds when the same contours were presented as holes instead of objects. If contours were perceived as belonging to the hole rather than the surrounding object then there would have been no qualitative difference in responses to the object and hole stimuli. We conclude that the contour bounding a hole is automatically assigned to the surrounding object, and that a change in perception of a region from object to hole always drastically changes the encoded information. We discuss the many interesting aspects of holes as a subject of study in different disciplines and predict that much insight especially about shape will continue to come from holes.

Form Perception↗
PubMed2003

Visual comparisons within and between object parts: evidence for a single-part superiority effect.

Subjects judged whether two marks placed at different positions along a curved contour were physically the same. When targets were separated by a concave curvature extremum--corresponding to a part-boundary--decision latencies were longer than when they straddled an equally curved convex extremum, demonstrating a "single-part superiority effect". This difference increased with both stimulus duration and the magnitude of contour curvature. However, it disappeared when the global configuration was not consistent with a part-boundary interpretation, suggesting a critical role of global organization in part decomposition.

Form Perception↗