DS-1998-05: Languages of Perception

DS-1998-05: Dastani, Mehdi (1998) Languages of Perception. Doctoral thesis, University of Amsterdam.

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%Nr: DS-1998-05
%Author: Mehdi Dastani
%Title: Languages of Perception

In everyday life, we are confronted with visual information
provided by the environment. This visual information may
originate from the scenes of cities or forests, but also from
television images, computer interfaces, and many other natural or
artificial sources. In general, we have no difficulties in
recognizing meaningful entities in the visual information we
receive, and in organizing it coherently. For example, when we
look at an urban neighborhood which we have never seen before, we
perceive individual buildings and separate them from each other
even when they are continuously bounded to each other. Also, in a
natural environment, we easily perceive individual flowers,
plants, or trees and discriminate them from each other even when
one is partially hidden by the other. Although this ability seems
to be effortless and direct, it is far from trivial to
understand, describe, and model it.

In order to understand and model the human visual system, one
should analyze visual information as it is presented to human
visual sensors (human eyes) and describe how this information can
be mapped into meaningful entities for which we have names and
which we can place in a conceptual framework. We assume two steps
in mapping visual information into meaningful entities. The first
step concerns the low-level structuring of visual information.
This step provides the constituent structure of visual
information, i.e. it determines: A) constituents of visual
information and B) how they are composed to build up larger
wholes. In the second step, the visual constituents resulting
from the first step should then be interpreted in some conceptual
framework. The interpretation of visual constituents is based on
many factors such as reasoning and past experiences. It should be
noted that these two steps interact with each other: when the
structured visual information from the first step cannot be
placed into a conceptual framework coherently, the low-level
structuring step should provide an alternative constituent
structure for the visual input.

In this thesis, we will concentrate on the first step of
structuring visual information and investigate the principles on
the basis of which visual constituents are composed to form
larger wholes. However, we do not discuss how primitive visual
constituents are determined. In an ultimate theory, these should
probably be pixels, line-segments, and/or edges between
contrastive areas. But for the moment we will avoid commitments
about this issue, by focusing on classes of pictures for which a
particular type of higher-level units may be assumed as
primitives. What we focus on in this thesis is the problem of
gestalt perception: assuming a set of primitive elements, we try
to account for the phenomena that pictures built up of these
elements are perceived by humans as having a particular
hierarchical constituent structure. In the study of gestalt
perception primitive elements are assumed to be composed and
structured unconsciously and directly according to some innate
principles that are believed to underlie the human visual system.
During the last century, there have been several formulations for
these suggested innate principles. We start with a recent
formulation of the innate principles of the human visual system
and develop a mathematical model for gestalt perception. We
discuss various aspects of gestalt perception and work out an
application in which a model of human visual system is

Item Type: Thesis (Doctoral)
Report Nr: DS-1998-05
Series Name: ILLC Dissertation (DS) Series
Year: 1998
Subjects: Language
Depositing User: Dr Marco Vervoort
Date Deposited: 14 Jun 2022 15:16
Last Modified: 14 Jun 2022 15:16
URI: https://eprints.illc.uva.nl/id/eprint/2008

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