当前的文本到视频检索方法(T2VR)经过培训和测试,并在视频捕获方向的数据集(例如MSVD,MSR-VTT和VATEX)上进行了测试。这些数据集的一个关键属性是,假定视频在短时间内被暂时预先修剪,而提供的字幕很好地描述了视频内容的要旨。因此,对于给定的配对视频和标题,该视频应该与标题完全相关。但是,实际上,由于查询尚不清楚,因此预处理的视频剪辑可能不包含足够的内容来完全满足查询。这表明文学与现实世界之间存在差距。为了填补空白,我们在本文中提出了一个新颖的T2VR子任务,称为部分相关的视频检索(PRVR)。未修剪的视频被认为是部分相关的W.R.T.给定的文本查询是否包含与查询相关的时刻。 PRVR旨在从大量未修剪视频中检索此类相关视频。 PRVR与单个视频时刻检索和视频语料库时刻的检索有所不同,因为后两个是要检索时刻而不是未修剪的视频。我们将PRVR作为多个实例学习(MIL)问题,同时将视频视为一袋视频片段和一袋视频帧。剪辑和帧表示不同时间尺度的视频内容。我们提出了一个多尺度的相似性学习(MS-SL)网络,该网络共同学习PRVR的剪辑规模和框架尺度相似性。在三个数据集(TVR,ActivityNet字幕和Charades-STA)上进行了广泛的实验,证明了该方法的可行性。我们还表明,我们的方法可用于改善视频语料库时刻的检索。
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Visual perception plays an important role in autonomous driving. One of the primary tasks is object detection and identification. Since the vision sensor is rich in color and texture information, it can quickly and accurately identify various road information. The commonly used technique is based on extracting and calculating various features of the image. The recent development of deep learning-based method has better reliability and processing speed and has a greater advantage in recognizing complex elements. For depth estimation, vision sensor is also used for ranging due to their small size and low cost. Monocular camera uses image data from a single viewpoint as input to estimate object depth. In contrast, stereo vision is based on parallax and matching feature points of different views, and the application of deep learning also further improves the accuracy. In addition, Simultaneous Location and Mapping (SLAM) can establish a model of the road environment, thus helping the vehicle perceive the surrounding environment and complete the tasks. In this paper, we introduce and compare various methods of object detection and identification, then explain the development of depth estimation and compare various methods based on monocular, stereo, and RDBG sensors, next review and compare various methods of SLAM, and finally summarize the current problems and present the future development trends of vision technologies.
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交付机器人旨在获得高精度以促进完全自主权。需要一个精确的人行行周围环境的三维点云图来估计自定位。有或没有循环结束方法,由于传感器漂移,较大的城市或城市地图映射后累积误差会逐渐增加。因此,使用漂移或错位的地图存在很高的风险。本文提出了一种融合GPS更新3D点云并消除累积错误的技术。提出的方法与其他现有方法显示了定量比较和定性评估的出色结果。
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在过去几年中,自动驾驶一直是最受欢迎,最具挑战性的主题之一。在实现完全自治的道路上,研究人员使用了各种传感器,例如LIDAR,相机,惯性测量单元(IMU)和GPS,并开发了用于自动驾驶应用程序的智能算法,例如对象检测,对象段,障碍,避免障碍物,避免障碍物和障碍物,以及路径计划。近年来,高清(HD)地图引起了很多关注。由于本地化中高清图的精度和信息水平很高,因此它立即成为自动驾驶的关键组成部分之一。从Baidu Apollo,Nvidia和TomTom等大型组织到个别研究人员,研究人员创建了用于自主驾驶的不同场景和用途的高清地图。有必要查看高清图生成的最新方法。本文回顾了最新的高清图生成技术,这些技术利用了2D和3D地图生成。这篇评论介绍了高清图的概念及其在自主驾驶中的有用性,并详细概述了高清地图生成技术。我们还将讨论当前高清图生成技术的局限性,以激发未来的研究。
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Deep learning models can achieve high accuracy when trained on large amounts of labeled data. However, real-world scenarios often involve several challenges: Training data may become available in installments, may originate from multiple different domains, and may not contain labels for training. Certain settings, for instance medical applications, often involve further restrictions that prohibit retention of previously seen data due to privacy regulations. In this work, to address such challenges, we study unsupervised segmentation in continual learning scenarios that involve domain shift. To that end, we introduce GarDA (Generative Appearance Replay for continual Domain Adaptation), a generative-replay based approach that can adapt a segmentation model sequentially to new domains with unlabeled data. In contrast to single-step unsupervised domain adaptation (UDA), continual adaptation to a sequence of domains enables leveraging and consolidation of information from multiple domains. Unlike previous approaches in incremental UDA, our method does not require access to previously seen data, making it applicable in many practical scenarios. We evaluate GarDA on two datasets with different organs and modalities, where it substantially outperforms existing techniques.
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The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.
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As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.
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Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.
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We propose a distributionally robust return-risk model for Markov decision processes (MDPs) under risk and reward ambiguity. The proposed model optimizes the weighted average of mean and percentile performances, and it covers the distributionally robust MDPs and the distributionally robust chance-constrained MDPs (both under reward ambiguity) as special cases. By considering that the unknown reward distribution lies in a Wasserstein ambiguity set, we derive the tractable reformulation for our model. In particular, we show that that the return-risk model can also account for risk from uncertain transition kernel when one only seeks deterministic policies, and that a distributionally robust MDP under the percentile criterion can be reformulated as its nominal counterpart at an adjusted risk level. A scalable first-order algorithm is designed to solve large-scale problems, and we demonstrate the advantages of our proposed model and algorithm through numerical experiments.
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Witnessing the impressive achievements of pre-training techniques on large-scale data in the field of computer vision and natural language processing, we wonder whether this idea could be adapted in a grab-and-go spirit, and mitigate the sample inefficiency problem for visuomotor driving. Given the highly dynamic and variant nature of the input, the visuomotor driving task inherently lacks view and translation invariance, and the visual input contains massive irrelevant information for decision making, resulting in predominant pre-training approaches from general vision less suitable for the autonomous driving task. To this end, we propose PPGeo (Policy Pre-training via Geometric modeling), an intuitive and straightforward fully self-supervised framework curated for the policy pretraining in visuomotor driving. We aim at learning policy representations as a powerful abstraction by modeling 3D geometric scenes on large-scale unlabeled and uncalibrated YouTube driving videos. The proposed PPGeo is performed in two stages to support effective self-supervised training. In the first stage, the geometric modeling framework generates pose and depth predictions simultaneously, with two consecutive frames as input. In the second stage, the visual encoder learns driving policy representation by predicting the future ego-motion and optimizing with the photometric error based on current visual observation only. As such, the pre-trained visual encoder is equipped with rich driving policy related representations and thereby competent for multiple visuomotor driving tasks. Extensive experiments covering a wide span of challenging scenarios have demonstrated the superiority of our proposed approach, where improvements range from 2% to even over 100% with very limited data. Code and models will be available at https://github.com/OpenDriveLab/PPGeo.
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