Estimating 3D Finger Angle on Commodity Touchscreens

We describe a novel approach for estimating the pitch and yaw of fingers relative to a touchscreen's surface, offering two additional, analog degrees of freedom for interactive functions. Further, we show that our approach can be achieved on off-the-shelf consumer touchscreen devices: a smartphone and smartwatch. We validate our technique though a user study on both devices and conclude with several demo applications that illustrate the value and immediate feasibility of our approach.