Expression Glasses provide a wearable "appliance-based" alternative to general-purpose
machine vision face recognition systems. The glasses sense facial muscle movements,
and use pattern recognition to identify meaningful expressions such as confusion or
interest. A prototype of the glasses has been built and evaluated. The prototype uses
piezoelectric sensors hidden in a visor extension to a pair of glasses, providing for
compactness, user control, and anonymity. On users who received no training or feedback,
the glasses initially performed at 94% accuracy in detecting an expression, and at 74%
accuracy in recognizing whether the expression was confusion or interest. Significant
improvement beyond these numbers appears to be possible with extended use, and with a
small amount of feedback (letting the user see the output of the system).