这项工作研究了图像目标导航问题,需要通过真正拥挤的环境引导具有嘈杂传感器和控制的机器人。最近的富有成效的方法依赖于深度加强学习,并学习模拟环境中的导航政策,这些环境比真实环境更简单。直接将这些训练有素的策略转移到真正的环境可能非常具有挑战性甚至危险。我们用由四个解耦模块组成的分层导航方法来解决这个问题。第一模块在机器人导航期间维护障碍物映射。第二个将定期预测实时地图上的长期目标。第三个计划碰撞命令集以导航到长期目标,而最终模块将机器人正确靠近目标图像。四个模块是单独开发的,以适应真实拥挤的情景中的图像目标导航。此外,分层分解对导航目标规划,碰撞避免和导航结束预测的学习进行了解耦,这在导航训练期间减少了搜索空间,并有助于改善以前看不见的真实场景的概括。我们通过移动机器人评估模拟器和现实世界中的方法。结果表明,我们的方法优于多种导航基线,可以在这些方案中成功实现导航任务。
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我们介绍了一个目标驱动的导航系统,以改善室内场景中的Fapless视觉导航。我们的方法在每次步骤中都将机器人和目标的多视图观察为输入,以提供将机器人移动到目标的一系列动作,而不依赖于运行时在运行时。通过优化包含三个关键设计的组合目标来了解该系统。首先,我们建议代理人在做出行动决定之前构建下一次观察。这是通过从专家演示中学习变分生成模块来实现的。然后,我们提出预测预先预测静态碰撞,作为辅助任务,以改善导航期间的安全性。此外,为了减轻终止动作预测的训练数据不平衡问题,我们还介绍了一个目标检查模块来区分与终止动作的增强导航策略。这三种建议的设计都有助于提高培训数据效率,静态冲突避免和导航泛化性能,从而产生了一种新颖的目标驱动的FLASES导航系统。通过对Turtlebot的实验,我们提供了证据表明我们的模型可以集成到机器人系统中并在现实世界中导航。视频和型号可以在补充材料中找到。
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为了基于深度加强学习(RL)来增强目标驱动的视觉导航的交叉目标和跨场景,我们将信息理论正则化术语引入RL目标。正则化最大化导航动作与代理的视觉观察变换之间的互信息,从而促进更明智的导航决策。这样,代理通过学习变分生成模型来模拟动作观察动态。基于该模型,代理生成(想象)从其当前观察和导航目标的下一次观察。这样,代理学会了解导航操作与其观察变化之间的因果关系,这允许代理通过比较当前和想象的下一个观察来预测导航的下一个动作。 AI2-Thor框架上的交叉目标和跨场景评估表明,我们的方法在某些最先进的模型上获得了平均成功率的10美元。我们进一步评估了我们的模型在两个现实世界中:来自离散的活动视觉数据集(AVD)和带有TurtleBot的连续现实世界环境中的看不见的室内场景导航。我们证明我们的导航模型能够成功实现导航任务这些情景。视频和型号可以在补充材料中找到。
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Brain midline shift (MLS) is one of the most critical factors to be considered for clinical diagnosis and treatment decision-making for intracranial hemorrhage. Existing computational methods on MLS quantification not only require intensive labeling in millimeter-level measurement but also suffer from poor performance due to their dependence on specific landmarks or simplified anatomical assumptions. In this paper, we propose a novel semi-supervised framework to accurately measure the scale of MLS from head CT scans. We formulate the MLS measurement task as a deformation estimation problem and solve it using a few MLS slices with sparse labels. Meanwhile, with the help of diffusion models, we are able to use a great number of unlabeled MLS data and 2793 non-MLS cases for representation learning and regularization. The extracted representation reflects how the image is different from a non-MLS image and regularization serves an important role in the sparse-to-dense refinement of the deformation field. Our experiment on a real clinical brain hemorrhage dataset has achieved state-of-the-art performance and can generate interpretable deformation fields.
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Current mainstream object detection methods for large aerial images usually divide large images into patches and then exhaustively detect the objects of interest on all patches, no matter whether there exist objects or not. This paradigm, although effective, is inefficient because the detectors have to go through all patches, severely hindering the inference speed. This paper presents an Objectness Activation Network (OAN) to help detectors focus on fewer patches but achieve more efficient inference and more accurate results, enabling a simple and effective solution to object detection in large images. In brief, OAN is a light fully-convolutional network for judging whether each patch contains objects or not, which can be easily integrated into many object detectors and jointly trained with them end-to-end. We extensively evaluate our OAN with five advanced detectors. Using OAN, all five detectors acquire more than 30.0% speed-up on three large-scale aerial image datasets, meanwhile with consistent accuracy improvements. On extremely large Gaofen-2 images (29200$\times$27620 pixels), our OAN improves the detection speed by 70.5%. Moreover, we extend our OAN to driving-scene object detection and 4K video object detection, boosting the detection speed by 112.1% and 75.0%, respectively, without sacrificing the accuracy. Code is available at https://github.com/Ranchosky/OAN.
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We study the problem of semantic segmentation calibration. For image classification, lots of existing solutions are proposed to alleviate model miscalibration of confidence. However, to date, confidence calibration research on semantic segmentation is still limited. We provide a systematic study on the calibration of semantic segmentation models and propose a simple yet effective approach. First, we find that model capacity, crop size, multi-scale testing, and prediction correctness have impact on calibration. Among them, prediction correctness, especially misprediction, is more important to miscalibration due to over-confidence. Next, we propose a simple, unifying, and effective approach, namely selective scaling, by separating correct/incorrect prediction for scaling and more focusing on misprediction logit smoothing. Then, we study popular existing calibration methods and compare them with selective scaling on semantic segmentation calibration. We conduct extensive experiments with a variety of benchmarks on both in-domain and domain-shift calibration, and show that selective scaling consistently outperforms other methods.
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In this paper, we propose a large-scale language pre-training for text GENeration using dIffusion modEl, which is named GENIE. GENIE is a pre-training sequence-to-sequence text generation model which combines Transformer and diffusion. The diffusion model accepts the latent information from the encoder, which is used to guide the denoising of the current time step. After multiple such denoise iterations, the diffusion model can restore the Gaussian noise to the diverse output text which is controlled by the input text. Moreover, such architecture design also allows us to adopt large scale pre-training on the GENIE. We propose a novel pre-training method named continuous paragraph denoise based on the characteristics of the diffusion model. Extensive experiments on the XSum, CNN/DailyMail, and Gigaword benchmarks shows that GENIE can achieves comparable performance with various strong baselines, especially after pre-training, the generation quality of GENIE is greatly improved. We have also conduct a lot of experiments on the generation diversity and parameter impact of GENIE. The code for GENIE will be made publicly available.
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Developing autonomous vehicles (AVs) helps improve the road safety and traffic efficiency of intelligent transportation systems (ITS). Accurately predicting the trajectories of traffic participants is essential to the decision-making and motion planning of AVs in interactive scenarios. Recently, learning-based trajectory predictors have shown state-of-the-art performance in highway or urban areas. However, most existing learning-based models trained with fixed datasets may perform poorly in continuously changing scenarios. Specifically, they may not perform well in learned scenarios after learning the new one. This phenomenon is called "catastrophic forgetting". Few studies investigate trajectory predictions in continuous scenarios, where catastrophic forgetting may happen. To handle this problem, first, a novel continual learning (CL) approach for vehicle trajectory prediction is proposed in this paper. Then, inspired by brain science, a dynamic memory mechanism is developed by utilizing the measurement of traffic divergence between scenarios, which balances the performance and training efficiency of the proposed CL approach. Finally, datasets collected from different locations are used to design continual training and testing methods in experiments. Experimental results show that the proposed approach achieves consistently high prediction accuracy in continuous scenarios without re-training, which mitigates catastrophic forgetting compared to non-CL approaches. The implementation of the proposed approach is publicly available at https://github.com/BIT-Jack/D-GSM
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Data compression is becoming critical for storing scientific data because many scientific applications need to store large amounts of data and post process this data for scientific discovery. Unlike image and video compression algorithms that limit errors to primary data, scientists require compression techniques that accurately preserve derived quantities of interest (QoIs). This paper presents a physics-informed compression technique implemented as an end-to-end, scalable, GPU-based pipeline for data compression that addresses this requirement. Our hybrid compression technique combines machine learning techniques and standard compression methods. Specifically, we combine an autoencoder, an error-bounded lossy compressor to provide guarantees on raw data error, and a constraint satisfaction post-processing step to preserve the QoIs within a minimal error (generally less than floating point error). The effectiveness of the data compression pipeline is demonstrated by compressing nuclear fusion simulation data generated by a large-scale fusion code, XGC, which produces hundreds of terabytes of data in a single day. Our approach works within the ADIOS framework and results in compression by a factor of more than 150 while requiring only a few percent of the computational resources necessary for generating the data, making the overall approach highly effective for practical scenarios.
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Inspired by the recent success of Transformers for Natural Language Processing and vision Transformer for Computer Vision, many researchers in the medical imaging community have flocked to Transformer-based networks for various main stream medical tasks such as classification, segmentation, and estimation. In this study, we analyze, two recently published Transformer-based network architectures for the task of multimodal head-and-tumor segmentation and compare their performance to the de facto standard 3D segmentation network - the nnU-Net. Our results showed that modeling long-range dependencies may be helpful in cases where large structures are present and/or large field of view is needed. However, for small structures such as head-and-neck tumor, the convolution-based U-Net architecture seemed to perform well, especially when training dataset is small and computational resource is limited.
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