Deep networks have been proved to encode high-level features with semantic meaning and delivered superior performance in salient object detection. In this paper, we take one step further by developing a new saliency detection method based on recurrent fully convolutional networks (RFCNs). Compared with existing deep network based methods, the proposed network is able to incorpor- ate saliency prior knowledge for more accurate inference. In addition, the recurrent architecture enables our method to automatically learn to refine the saliency map by iteratively correcting its previous errors, yielding more reliable final predictions. To train such a netw- ork with numerous parameters, we propose a pre-training strategy using semantic segmentation data, which simultaneously leverages the strong supervision of segmentation tasks for effective training and enables the network to capture generic representations to chara- cterize category-agnostic objects for saliency detection. Extensive experimental evaluations demonstrate that the proposed method compares favorably against state-of-the-art saliency detection approaches. Additional validations are also performed to study the impact of the recurrent architecture and pre-training strategy on both saliency detection and semantic segmentation, which provides important knowledge for network design and training in the future research.
Linzhao Wang, Lijun Wang, Huchuan Lu
IEEE Transactions on Pattern Analysis and Machine Intelligence