Nonlocal Neural Networks, Nonlocal Diffusion and Nonlocal Modeling
Nonlocal neural networks have been proposed and shown to be effective in several computer vision tasks, where the nonlocal operations can directly capture long-range dependencies in the feature space. In this paper, we study the nature of diffusion and damping effect of nonlocal networks by doing the spectrum analysis on the weight matrices of the well-trained networks, and propose a new formulation of the nonlocal block. The new block not only learns the nonlocal interactions but also has stable dynamics and thus allows deeper nonlocal structures. Moreover, we interpret our formulation from the general nonlocal modeling perspective, where we make connections between the proposed nonlocal network and other nonlocal models, such as nonlocal diffusion processes and nonlocal Markov jump processes.
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