In-air signature is a new modality which is essential for user authentication and access control in noncontact mode and has been actively studied in recent years.  ...  Inspired by the great progress in deep-learning-based hand pose estimation, we propose a real-time in-air signature acquisition method which estimates hand joint positions in 3D using a single depth image  ...  presented a real-time automatic in-air signature acquisition and verification framework using a low cost multi-modal depth camera.  ...