Microgesture ＋ Grasp: A journey from human capabilities to interaction with microgestures

Microgestures, i.e. fast and subtle finger movements, have shown a high potential for ubiquitous interaction. However, work to-date either focuses on grasp contexts (holding an object) or on the free-hand context (no held object). These two contexts influence the microgestures feasibility. Researchers have created sets of microgesture feasible across the entire taxonomy of everyday grasps, called transferable microgestures. However, those sets include a limited number of microgestures as compared to those for the free-hand context, for which microgestures are distinguished according to fine characteristics such as the part of the finger being touched or the number of fingers used. We provide knowledge and methods for identifying and recognizing microgestures that can transfer across contexts. First, we report a study on ergonomics factors that influence the feasibility of a microgesture in a given context. Then, we propose a conceptual model serving as a tool to determine the feasibility of a microgesture in a given context without the need for time-consuming user studies. As expected, not all microgestures were transferable to all considered contexts. Thus, we then expose two different ways of defining a set of microgestures transferable between free-hand and grasping contexts. Finally, we report a user study on recognition factors of a transferable microgesture set.