abstract = "Emotions are an integral part of human daily life as
they can influence behaviour. A reliable emotion
detection system may help people in varied things, such
as social contact, health care and gaming experience.
Emotions can often be identified by facial expressions,
but this can be difficult to achieve reliably as people
are different and a person can mask or suppress an
expression. Instead of analysis on static image, the
computing of the motion of an expression occurrence
plays more important role for these reasons. The work
described in this thesis considers an automated and
objective approach to recognition of facial expressions
using extracted optical flow, which may be a reliable
alternative to human interpretation. The Farneback fast
estimation has been used for the dense optical flow
extraction. Evolutionary algorithms, inspired by
Darwinian evolution, have been shown to perform well on
complex,nonlinear datasets and are considered for the
basis of this automated approach. Specifically,
Cartesian Genetic Programming (CGP) is implemented,
which can find computer programme that approaches
user-defined tasks by the evolution of solutions, and
modified to work as a classifier for the analysis of
extracted flow data. Its performance compared with
Support Vector Machine (SVM), which has been widely
used in expression recognition problem, on a range of
pre-recorded facial expressions obtained from two
separate databases (MMI and FG-NET). CGP was shown
flexible to optimise in the experiments: the imbalanced
data classification problem is sharply reduced by
applying an Area under Curve (AUC) based fitness
function. Results presented suggest that CGP is capable
to achieve better performance than SVM. An automatic
expression recognition system has also been implemented
based on the method described in the thesis. The future
work is to propose investigation of an ensemble
classifier implementing both CGP and SVM.",