More recently there have been several purely data-driven end-to-end approaches to sign recognition from continuous signing based on Recurrent Neural Net (RNN) architectures (Cui, Liu, and Zhang, 2017;Koller, Zargaran, and Ney, 2017).
the performance of these imagebased approaches is held back by limitations in the data- Figure 1: Framework Overview sets and the fact that they do not integrate linguistic knowledge and perform 3D analysis.