We address the problem of retrieving a specific moment from an untrimmed video by a query sentence. This is a challenging problem because a target moment may take place in relations to other temporal moments in the untrimmed video. Existing methods cannot tackle this challenge well since they consider temporal moments individually and neglect the temporal dependencies. In this paper, we model the temporal relations between video moments by a two-dimensional map, where one dimension indicates the starting time of a moment and the other indicates the end time. This 2D temporal map can cover diverse video moments with different lengths, while representing their adjacent relations. Based on the 2D map, we propose a Temporal Adjacent Network (2D-TAN), a single-shot framework for moment localization. It is capable of encoding the adjacent temporal relation, while learning discriminative features for matching video moments with referring expressions. We evaluate the proposed 2D-TAN on three challenging benchmarks, i.e., Charades-STA, ActivityNet Captions, and TACoS, where our 2D-TAN outperforms the state-of-the-art.

本文提出了一个基于2D时间映射的Temporal Adjacent Network（2D-TAN）框架，用于在未修剪的视频中匹配与查询句子相关的特定时间点，该框架可以编码相邻的时间关系，并学习具有区分性的特征以提高活动识别的准确性，通过在Charades-STA，ActivityNet Captions和TACoS等数据集上的表现，证明了该方法的优越性。

自然语言时序相邻网络学习用于时刻定位