TouchLog: Finger Micro Gesture Recognition Using Photo-Reflective Sensors

Fingertip input allows for interactions that are natural, easy to perform, and socially acceptable. It also has advantages in terms of low physical demand, confidentiality, and haptic feedback. In this study, we propose TouchLog, a fingernail-type device that uses skin deformation of the fingertip to identify finger micro gestures written with the thumb on the index finger. TouchLog is attached to the index fingernail and allows for one-handed fingertip input without compromising the haptic feedback on the finger. To evaluate the accuracy of 11 types of finger micro gesture recognition, we conducted a user study (N = 10) and obtained an average identification accuracy of 91.5\% (SD = 3.1\%). A continuous input method using skin deformation and contact pressure was also examined, and its usefulness as a wearable device was discussed.