ÐSophisticated mathematical algorithms (such as differencing, thresholding,
aggregation and statistical analysis of skin colours) are used to compare successive
frames of computer-captured images of the face. From these, changes in state of the
eyes are determined and are used to detect blinks. A recognition performance of
83.74+0.03% is achieved over ®ve subjects with a low rate of false positives
2.71+0.01%. A logical decision rule identi®es purposeful blinks and applies them
to control either a custom-designed communication package or an external device