  Facial features deformed according to the intended facial expression.
Specific facial features are associated with specific facial expression, i.e.
happy means the deformation of mouth. This paper presents the study of facial
feature deformation for each facial expression by using an optical flow
algorithm and segmented into three different regions of interest. The
deformation of facial features shows the relation between facial the and facial
expression. Based on the experiments, the deformations of eye and mouth are
significant in all expressions except happy. For happy expression, cheeks and
mouths are the significant regions. This work also suggests that different
facial features' intensity varies in the way that they contribute to the
recognition of the different facial expression intensity. The maximum magnitude
across all expressions is shown by the mouth for surprise expression which is
9x10-4. While the minimum magnitude is shown by the mouth for angry expression
which is 0.4x10-4.
