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Inferring the complete 3D shape of an object from an RGB image has shown impressive results, however, existing methods rely primarily on recognizing the most similar 3D model from the training set to solve the problem. These methods suffer from poor generalization and may lead to low-quality reconstructions for unseen objects. Nowadays, stereo cameras are pervasive in emerging devices such as dual-lens smartphones and robots, which enables the use of the two-view nature of stereo images to explore the 3D structure and thus improve the reconstruction performance. In this paper, we propose a new deep learning framework for reconstructing the 3D shape of an object from a pair of stereo images, which reasons about the 3D structure of the object by taking bidirectional disparities and feature correspondences between the two views into account. Besides, we present a large-scale synthetic benchmarking dataset, namely StereoShapeNet , containing 1,052,976 pairs of stereo images rendered from ShapeNet along with the corresponding bidirectional depth and disparity maps. Experimental results on the StereoShapeNet benchmark demonstrate that the proposed framework outperforms the state-of-the-art methods. The project page is available at https://haozhexie.com/project/stereo-3d-reconstruction. [ABSTRACT FROM AUTHOR]

Recognition of general actions has witnessed great success in recent years. However, the existing general action representations cannot work well to recognize fine-grained actions, which usually share high similarities in both appearance and motion pattern. To solve this problem, we introduce the visual attention mechanism into the proposed descriptor, termed Actionness-pooled Deep-convolutional Descriptor (ADD). Instead of pooling features uniformly from the entire video, we aggregate features in sub-regions that are more likely to contain actions according to actionness maps. This endows ADD with the superior capability of capturing the subtle differences between fine-grained actions. We conduct experiments on HIT Dances dataset, one of the few existing datasets for fine-grained action analysis. Quantitative results have demonstrated that ADD remarkably outperforms traditional CNN-based representations. Extensive experiments on two general action benchmarks, JHMDB and UCF101, have additionally proved that combining ADD with end-to-end ConvNet can further boost the recognition performance. Besides, taking advantage of ADD, we reveal the sparsity characteristic existing in actions and point out a potential direction to design more effective action analysis models by extracting both representative and discriminative action patterns. [ABSTRACT FROM AUTHOR]