  Augmenting human computer interaction with automated analysis and synthesis
of facial expressions is a goal towards which much research effort has been
devoted recently. Facial gesture recognition is one of the important component
of natural human-machine interfaces; it may also be used in behavioural
science, security systems and in clinical practice. Although humans recognise
facial expressions virtually without effort or delay, reliable expression
recognition by machine is still a challenge. The face expression recognition
problem is challenging because different individuals display the same
expression differently. This paper presents an overview of gesture recognition
in real time using the concepts of correlation and Mahalanobis distance.We
consider the six universal emotional categories namely joy, anger, fear,
disgust, sadness and surprise.
