  Gesture recognition is a much studied research area which has myriad
real-world applications including robotics and human-machine interaction.
Current gesture recognition methods have focused on recognising isolated
gestures, and existing continuous gesture recognition methods are limited to
two-stage approaches where independent models are required for detection and
classification, with the performance of the latter being constrained by
detection performance. In contrast, we introduce a single-stage continuous
gesture recognition framework, called Temporal Multi-Modal Fusion (TMMF), that
can detect and classify multiple gestures in a video via a single model. This
approach learns the natural transitions between gestures and non-gestures
without the need for a pre-processing segmentation step to detect individual
gestures. To achieve this, we introduce a multi-modal fusion mechanism to
support the integration of important information that flows from multi-modal
inputs, and is scalable to any number of modes. Additionally, we propose
Unimodal Feature Mapping (UFM) and Multi-modal Feature Mapping (MFM) models to
map uni-modal features and the fused multi-modal features respectively. To
further enhance performance, we propose a mid-point based loss function that
encourages smooth alignment between the ground truth and the prediction,
helping the model to learn natural gesture transitions. We demonstrate the
utility of our proposed framework, which can handle variable-length input
videos, and outperforms the state-of-the-art on three challenging datasets:
EgoGesture, IPN hand, and ChaLearn LAP Continuous Gesture Dataset (ConGD).
Furthermore, ablation experiments show the importance of different components
of the proposed framework.
