A Deep Learning Framework for Recognizing both Static and Dynamic Gestures

Intuitive user interfaces are indispensable to interact with human centric smart environments. In this paper, we propose a unified framework that recognizes both static and dynamic gestures, using simple RGB vision (without depth sensing). This feature makes it suitable for inexpensive human-machine interaction (HMI). We rely on a spatial attention-based strategy, which employs SaDNet, our proposed Static and Dynamic gestures Network. From the image of the human upper body, we estimate his/her depth, along with the region-of-interest around his/her hands. The Convolutional Neural Networks in SaDNet are fine-tuned on a background-substituted hand gestures dataset. They are utilized to detect 10 static gestures for each hand and to obtain hand image-embeddings from the last Fully Connected layer, which are subsequently fused with the augmented pose vector and then passed to stacked Long Short-Term Memory blocks. Thus, human-centered frame-wise information from the augmented pose vector and left/right hands image-embeddings are aggregated in time to predict the dynamic gestures of the performing person. In a number of experiments we show that the proposed approach surpasses the state-of-the-art results on large-scale Chalearn 2016 dataset. Moreover, we also transfer the knowledge learned through the proposed methodology to the Praxis gestures dataset, and the obtained results also outscore the state-of-the-art on this dataset.