From geons
to structure:
A note on object representation
Emanuel L. J. Leeuwenberg, Peter A. van der
Helm, Rob J. van Lier
Abstract.
Two models of object perception are compared: recognition by components
(RBC), proposed by Biederman, and structural information theory (SIT),
initially proposed by Leeuwenberg. According to RBC a complex object is
decomposed
into predefined elementary objects, called geons. According to SIT, the
decomposition is guided by regularities in the object. Is is assumed
that the simplest
of all possible interpretations of any object is perceptually
preferred.
The comparison deals with two aspects of the models. One is the
representation of simple objects -- various definitions of object axes
are considered.
It is shown that the more these definitions accounts for object
regularity
and thus the more they agree with SIT, the better the object
representations
predict object classification. Another topic concerns assumptions
underlying
the models: the identification of geons is mediated by cues which are
supposed to be invariant under varying viewpoints of objects. It is
argued that such cues are not based on this invariance but on the
regularity of actual objects. The latter conclusion is in line with
SIT. An advantage of RBC, however,
is that it deals with the perceptual process from stimulus to
interpretation, whereas SIT merely concerns the outcome of the process,
not the process
itself.
Peter
A. van der Helm 