Continuous sign language recognition based on hierarchical memory sequence network

With the goal of solving the problem of feature extractors lacking strong supervision training and insufficient time information concerning single-sequence model learning, a hierarchical sequence memory network with a multi-level iterative optimisation strategy is proposed for continuous sign language recognition. This method uses the spatial-temporal fusion convolution network (STFC-Net) to extract the spatial-temporal information of RGB and Optical flow video frames to obtain the multi-modal visual features of a sign language video. Then, in order to enhance the temporal relationships of visual feature maps, the hierarchical memory sequence network is used to capture local utterance features and global context dependencies across time dimensions to obtain sequence features. Finally, the decoder decodes the final sentence sequence. In order to enhance the feature extractor, the authors adopted a multi-level iterative optimisation strategy to fine-tune STFC-Net and the utterance feature extractor. The experimental results on the RWTH-Phoenix-Weather multi-signer 2014 dataset and the Chinese sign language dataset show the effectiveness and superiority of this method.