Exploiting Serialized Fine-Grained Action Recognition Using WiFi Sensing

Gestures serve an important role in enabling natural interactions with computing devices, and they form an important part of everyday nonverbal communication. In increasingly many application scenarios of gesture interaction, such as gesture-based authentication, calligraphy, sketching, and even artistic expression, not only are the underlying gestures complex and consist of multiple strokes but also the correctness of the gestures depends on the order at which the strokes are performed. In this paper, we present WiCG, an innovative and novel WiFi sensing approach for capturing and providing feedback on stroke order. Our approach tracks the user’s hand movement during writing and exploits this information in combination with statistical methods and machine learning techniques to infer what characters have been written and at which stroke order. We consider Chinese calligraphy as our use case as the resulting gestures are highly complex, and their assessment depends on the correct stroke order. We develop a set of analyses and algorithms to overcome many issues of this challenging task. We have conducted extensive experiments and user studies to evaluate our approach. Experimental results show that our approach is highly effective in identifying the written characters and their written stroke order. We show that our approach can adapt to different deployment environments and user patterns.