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A fixation and viewpoint
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2 Perceptual Control Theory
Traditional approaches to Artificial Intelligence systems, including
Computer Vision, have been highly anthropomorphic in that they have
tried to emulate high-level behaviours, such as logical reasoning,
symbol manipulation and identification, which are only relevant to human
behaviour. The view taken here is that the key to understanding human
behaviour is to first look at the foundations upon which all living
systems are built and work upwards from there. Briefly raised in this
section are some of the main Cognitive Science issues relevant to the
modelling of AI systems and some of the engineering benefits that arise
out of such a naturally parsimonious approach.
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Functional Decomposition
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Natural systems are more appropriately modelled as distributed systems
than a collection of functionally distinct models with a central
controller.
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Representation
-
The nature of representation is probably one of the most prominent
debates in the AI world. Traditional approaches have gone for models
based upon explicit high-level or metric properties. The more likely
candidate for representation in neural systems is of distributions of
activations of neurons.
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Commitment
-
A major goal in much vision research is to deliver reconstructed 3-D
models of the world, irrespective of relevance, following the principle
of
least
commitment. Natural animate systems, on the other hand, follow the
principle of
most
commitment, in that it is only necessary to process what has meaning for
them.
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Feedback Control
-
Natural systems act continually upon feedback from the environment which
means it is not necessary to compute specific actions. Traditional AI
approaches are categorised by systems that are designed to compute
specific outputs.
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Situatedness
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Reasoning or symbolic systems which have no connection to any
environment tell us little about how systems acquire relevant semantics.
Natural systems being situated in a real environment, interact with and
experience meaningful events and objects directly.
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Action
-
Active systems benefit greatly from being able to change the state of
their perceived world and to acquire new information.
In consideration of producing a realistic cognitive model of a basic
vision-based, animate system the policies of the non-traditional
approaches and the principles of natural systems are adopted. Also noted
are significant engineering benefits for systems developed along these
lines.
-
Reconstruction
-
3-D mapping of an agent's environment is an extremely costly endeavour.
It requires processes and techniques that can measure the world, as well
as knowledge of its own position and the effects of changes to the world
due to its actions. A system which behaves independently of such
knowledge benefits from a simplified design that does not require
calibration or measurement mechanisms.
-
Action
-
A static vision system may have to transform internal representations if
its current viewpoint is not optimal. An active system, on the other
hand, does not require such complex processes, but is able, by moving to
a new viewpoint, to
transform
the world.
-
Perceptual Control
-
Continual update of its position relative to a goal perception removes
the necessity to compute specific outputs, which would have lead to the
architectural rationale of measure and model and its associated
complexity.
Next:
4 Control theory applied
Up:
A fixation and viewpoint
Previous:
2 Perceptual Control Theory
Rupert J Young
Mon Jul 7 17:45:52 BST 1997