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ANALOG VLSI VISION SYSTEMS
Vision is the process of extracting high level information from two
dimensional data arrays produced by energy (frequently visible light)
reflected or transmitted from objects in the real world. Human vision
is a complex process which builds a coherent three dimensional, realtime
model of the world from scenes of arbitrary complexity. The first
stages of the human computer vision process occurs in the first few
layers of the retina. My current project is an silicon retina using
mixed analog and digital CMOS technology with a base feature size
(lambda) of .18 microns. This chip can perform arbitrary convolution
operations (operations which produce an output array based on the
immediate neighbourhood of each input array cell) using analog product
and sum circuits. These operations can be used to perform some of
the early vision processing done in biological retinas. The advantages
of this approach include extremely high effective processing speeds
and the very low costs of a CMOS solution, at the cost of a lower
signal to noise ratio compared with other imaging array types (CCD).
By using the advantages of high speed signal processing to compensate
for the lower signal to noise ratio a produce a low cost, high capability
smart vision chip.
ARTIFICIAL LIFE
Artificial Life is a broad field encompassing the study of artificial
systems which in some way mimic biological organisms. My research
in this area focuses on the evolution of co-operative behaviours in
organisms which are able to estimate their degree of relatedness with
other organisms. Non-reciprocal altruism is able to evolve under conditions
where the altruist and the recipient are related, and where the cost
to the altruist is less than the benefit accrued to the recipient
times the degree of relatedness between the altruist and the recipient
(for example a parent/child or sibling relationship implies a relatedness
coefficient of .5). Evolutionary costs and benefits are indirectly
measured in terms of ultimate reproductive success. Because the true
index of relatedness is not directly available to organisms they must
use other markers to decide whether or not to make an altruistic gift
to another organism. In experiments, organisms capable of kin recognition
demonstrate tremendous evolutionary advantages over organisms which
are not. This has obvious analogs to real world biological systems
and may prove useful in developing useful software agents which cooperate
to solve group tasks.
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