Visual Content Recognition by Exploiting Semantic Feature Map with Attention and Multi-task Learning

Recent studies have shown that spatial relationships among objects are very important for visual recognition, since they can provide rich clues on object contexts within the images. In this article, we introduce a novel method to learn the Semantic Feature Map (SFM) with attention-based deep neural networks for image and video classification in an end-to-end manner, aiming to explicitly model the spatial object contexts within the images. In particular, we explicitly apply the designed gate units to the extracted object features for important objects selection and noise removal. These selected object features are then organized into the proposed SFM, which is a compact and discriminative representation with the spatial information among objects preserved. Finally, we employ either Fully Convolutional Networks (FCN) or Long-Short Term Memory (LSTM) as the classifiers on top of the SFM for content recognition. A novel multi-task learning framework with image classification loss, object localization loss, and grid labeling loss are also introduced to help better learn the model parameters. We conduct extensive evaluations and comparative studies to verify the effectiveness of the proposed approach on Pascal VOC 2007/2012 and MS-COCO benchmarks for image classification. In addition, the experimental results also show that the SFMs learned from the image domain can be successfully transferred to CCV and FCVID benchmarks for video classification.