In most cases, upgrading from a single-robot system to a multi-robot system comes with increases in system payload and task performance. On the other hand, many multi-robot systems in open environments still rely on teleoperation. Therefore, human performance can be the bottleneck in a teleoperated multi-robot system. Based on this idea, the multi-robot system's shared autonomy and control methods are emerging research areas in open environment robot operations. However, the question remains: how much does the bottleneck of the human agent impact the system performance in a multi-robot system? This research tries to explore the question through the performance comparison of teleoperating a single-robot system and a dual-robot system in a box-pushing task. This robot teleoperation experiment on human agents employs a web-based environment to simulate the robots' two-dimensional movement. The result provides evidence of the hardship for a single human when teleoperating with more than one robot, which indicates the necessity of shared autonomy in multi-robot systems.
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人类的生活是无价的。当需要完成危险或威胁生命的任务时,机器人平台可能是更换人类运营商的理想选择。我们在这项工作中重点关注的任务是爆炸性的手段。鉴于移动机器人在多种环境中运行时表现出强大的功能,机器人触觉有可能提供安全解决方案。但是,与人类的运作相比,在此阶段,自主权可能具有挑战性和风险。远程运行可能是完整的机器人自主权和人类存在之间的折衷方案。在本文中,我们提出了一种相对便宜的解决方案,可用于远程敏感和机器人远程操作,以使用腿部操纵器(即,腿部四足机器人的机器人和RGB-D传感)来协助爆炸的军械处置。我们提出了一种新型的系统集成,以解决四足动物全身控制的非平凡问题。我们的系统基于可穿戴的基于IMU的运动捕获系统,该系统用于远程操作和视觉触发性的VR耳机。我们在实验中验证了现实世界中的方法,用于需要全身机器人控制和视觉触发的机车操作任务。
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图像增强旨在通过修饰颜色和音调来提高照片的美学视觉质量,并且是专业数字摄影的必不可少的技术。近年来,基于学习的图像增强算法已达到有希望的表现,并吸引了日益普及。但是,典型的努力试图为所有像素的颜色转换构建一个均匀的增强子。它忽略了对照片重要的不同内容(例如,天空,海洋等)之间的像素差异,从而导致结果不令人满意。在本文中,我们提出了一个新颖的可学习背景知觉的4维查找表(4D LUT),该表通过适应性地学习照片上下文来实现每个图像中不同内容的增强。特别是,我们首先引入一个轻量级上下文编码器和一个参数编码器,以分别学习像素级类别的上下文图和一组图像自适应系数。然后,通过通过系数集成多个基础4D LUT来生成上下文感知的4D LUT。最后,可以通过将源图像和上下文图馈入融合的上下文感知的4D〜LUT来获得增强的图像。与传统的3D LUT(即RGB映射到RGB)相比,通常用于摄像机成像管道系统或工具,4D LUT,即RGBC(RGB+上下文)映射到RGB,可实现具有不同像素的颜色转换的最佳控制每个图像中的内容,即使它们具有相同的RGB值。实验结果表明,我们的方法在广泛使用的基准中优于其他最先进的方法。
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视频框架插值(VFI)旨在合成两个连续帧之间的中间框架。最先进的方法通常采用两步解决方案,其中包括1)通过基于流动的运动估计来生成本地光线的像素,2)将扭曲的像素混合以通过深神经合成网络形成全帧。但是,由于两个连续的帧不一致,新帧的扭曲功能通常不会对齐,这会导致扭曲和模糊的帧,尤其是在发生大型和复杂的运动时。为了解决这个问题,在本文中,我们提出了一种新颖的视频框架插值变压器(TTVFI)。特别是,我们以不一致的动作为查询令牌制定了扭曲的特征,并将运动轨迹中的相关区域从两个原始的连续帧中提出到键和值。在沿轨迹的相关令牌上学习了自我注意力,以通过端到端训练将原始特征融合到中间框架中。实验结果表明,我们的方法在四个广泛使用的VFI基准中优于其他最先进的方法。代码和预培训模型都将很快发布。
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Unsupervised approaches to learning in neural networks are of substantial interest for furthering artificial intelligence, both because they would enable the training of networks without the need for large numbers of expensive annotations, and because they would be better models of the kind of general-purpose learning deployed by humans. However, unsupervised networks have long lagged behind the performance of their supervised counterparts, especially in the domain of large-scale visual recognition. Recent developments in training deep convolutional embeddings to maximize non-parametric instance separation and clustering objectives have shown promise in closing this gap. Here, we describe a method that trains an embedding function to maximize a metric of local aggregation, causing similar data instances to move together in the embedding space, while allowing dissimilar instances to separate. This aggregation metric is dynamic, allowing soft clusters of different scales to emerge. We evaluate our procedure on several large-scale visual recognition datasets, achieving state-of-the-art unsupervised transfer learning performance on object recognition in ImageNet, scene recognition in Places 205, and object detection in PASCAL VOC.
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Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.
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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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Text clustering and topic extraction are two important tasks in text mining. Usually, these two tasks are performed separately. For topic extraction to facilitate clustering, we can first project texts into a topic space and then perform a clustering algorithm to obtain clusters. To promote topic extraction by clustering, we can first obtain clusters with a clustering algorithm and then extract cluster-specific topics. However, this naive strategy ignores the fact that text clustering and topic extraction are strongly correlated and follow a chicken-and-egg relationship. Performing them separately fails to make them mutually benefit each other to achieve the best overall performance. In this paper, we propose an unsupervised text clustering and topic extraction framework (ClusTop) which integrates text clustering and topic extraction into a unified framework and can achieve high-quality clustering result and extract topics from each cluster simultaneously. Our framework includes four components: enhanced language model training, dimensionality reduction, clustering and topic extraction, where the enhanced language model can be viewed as a bridge between clustering and topic extraction. On one hand, it provides text embeddings with a strong cluster structure which facilitates effective text clustering; on the other hand, it pays high attention on the topic related words for topic extraction because of its self-attention architecture. Moreover, the training of enhanced language model is unsupervised. Experiments on two datasets demonstrate the effectiveness of our framework and provide benchmarks for different model combinations in this framework.
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An increasing number of public datasets have shown a marked clinical impact on assessing anatomical structures. However, each of the datasets is small, partially labeled, and rarely investigates severe tumor subjects. Moreover, current models are limited to segmenting specific organs/tumors, which can not be extended to novel domains and classes. To tackle these limitations, we introduce embedding learned from Contrastive Language-Image Pre-training (CLIP) to segmentation models, dubbed the CLIP-Driven Universal Model. The Universal Model can better segment 25 organs and 6 types of tumors by exploiting the semantic relationship between abdominal structures. The model is developed from an assembly of 14 datasets with 3,410 CT scans and evaluated on 6,162 external CT scans from 3 datasets. We rank first on the public leaderboard of the Medical Segmentation Decathlon (MSD) and achieve the state-of-the-art results on Beyond The Cranial Vault (BTCV). Compared with dataset-specific models, the Universal Model is computationally more efficient (6x faster), generalizes better to CT scans from varying sites, and shows stronger transfer learning performance on novel tasks. The design of CLIP embedding enables the Universal Model to be easily extended to new classes without catastrophically forgetting the previously learned classes.
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Recent advances in self-supervised learning (SSL) in computer vision are primarily comparative, whose goal is to preserve invariant and discriminative semantics in latent representations by comparing siamese image views. However, the preserved high-level semantics do not contain enough local information, which is vital in medical image analysis (e.g., image-based diagnosis and tumor segmentation). To mitigate the locality problem of comparative SSL, we propose to incorporate the task of pixel restoration for explicitly encoding more pixel-level information into high-level semantics. We also address the preservation of scale information, a powerful tool in aiding image understanding but has not drawn much attention in SSL. The resulting framework can be formulated as a multi-task optimization problem on the feature pyramid. Specifically, we conduct multi-scale pixel restoration and siamese feature comparison in the pyramid. In addition, we propose non-skip U-Net to build the feature pyramid and develop sub-crop to replace multi-crop in 3D medical imaging. The proposed unified SSL framework (PCRLv2) surpasses its self-supervised counterparts on various tasks, including brain tumor segmentation (BraTS 2018), chest pathology identification (ChestX-ray, CheXpert), pulmonary nodule detection (LUNA), and abdominal organ segmentation (LiTS), sometimes outperforming them by large margins with limited annotations.
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