Shape constancy from novel views
Department of Psychological Sciences, Purdue University
West Lafayette IN, 47907-1364
Electronic correspondence should be addressed to: firstname.lastname@example.org
Abstract: Prior experiments
on shape constancy from novel views are inconclusive: some show that shapes
of objects can be recognized reliably from novel views, while others show
just the opposite. Our analysis of prior results suggests that shape
constancy from novel views is reliable when the object has properties which
constrain its shape: the object has volumetric primitives, surfaces, it
is symmetrical, it is composed of geons, its contours are planar, its images
provide useful topological information about its 3D structure. To test
the role of some of these constraints we performed a set of experiments.
Solid shapes (polyhedra) were shown on a computer monitor by means of Kinetic
Depth Effect. Experiment 1 showed that shape constancy can be reliably
achieved when a polyhedron is represented by its contours (most of the
constraints are present), but not when it is represented by vertices or
by a polygonal line connecting the vertices in a random order (all the
constraints are absent). Experiments 2 and 3 tested the role of individual
constraints. Results of these experiments show that shape constancy from
novel views is reliable when the object has planar contours, and when the
shapes of the contours together with topological information about the
relations among the contours allow for unique interpretation of the shape.
Symmetry of the object and the topological stability of its image also
contribute to shape constancy.
Pizlo, Z. & Stevenson, A. (1999) "Shape constancy from novel
views". Perception & Psychophysics 61, 1299-1307.
This is a fairly simple applet that rotates a 3D wireframe or pixel set.
It requires a Java-capable browser.
It works with most Java capable browsers. Successfully tested browsers/applet
Here is a list of browsers that work, but in a weird way:
Internet Explorer 4.0
Internet Explorer 3.0
Netscape Communicator 4.0
Appletviewer in JDK 1.1
Appletviewer in JVIEW 1.1
Conditions by Experiment
||Partially non-planar, symmetric
|Polygonal line (16 vertices)
||Polygonal line (7 vertices)
Applet by Filip Pizlo; page and algorithms written by:
Filip Pizlo, email@example.com
& Adam Stevenson, firstname.lastname@example.org