The reconstruction of images from their corresponding noisy Radon transform is a typical example of an ill-posed linear inverse problem as arising in the application of computerized tomography (CT). As the (na\"{\i}ve) solution does not depend on the measured data continuously, regularization is needed to re-establish a continuous dependence. In this work, we investigate simple, but yet still provably convergent approaches to learning linear regularization methods from data. More specifically, we analyze two approaches: One generic linear regularization that learns how to manipulate the singular values of the linear operator in an extension of [1], and one tailored approach in the Fourier domain that is specific to CT-reconstruction. We prove that such approaches become convergent regularization methods as well as the fact that the reconstructions they provide are typically much smoother than the training data they were trained on. Finally, we compare the spectral as well as the Fourier-based approaches for CT-reconstruction numerically, discuss their advantages and disadvantages and investigate the effect of discretization errors at different resolutions.
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Earthquakes, fire, and floods often cause structural collapses of buildings. The inspection of damaged buildings poses a high risk for emergency forces or is even impossible, though. We present three recent selected missions of the Robotics Task Force of the German Rescue Robotics Center, where both ground and aerial robots were used to explore destroyed buildings. We describe and reflect the missions as well as the lessons learned that have resulted from them. In order to make robots from research laboratories fit for real operations, realistic test environments were set up for outdoor and indoor use and tested in regular exercises by researchers and emergency forces. Based on this experience, the robots and their control software were significantly improved. Furthermore, top teams of researchers and first responders were formed, each with realistic assessments of the operational and practical suitability of robotic systems.
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This work proposes a new method for real-time dense 3d reconstruction for common 360{\deg} action cams, which can be mounted on small scouting UAVs during USAR missions. The proposed method extends a feature based Visual monocular SLAM (OpenVSLAM, based on the popular ORB-SLAM) for robust long-term localization on equirectangular video input by adding an additional densification thread that computes dense correspondences for any given keyframe with respect to a local keyframe-neighboorhood using a PatchMatch-Stereo-approach. While PatchMatch-Stereo-types of algorithms are considered state of the art for large scale Mutli-View-Stereo they had not been adapted so far for real-time dense 3d reconstruction tasks. This work describes a new massively parallel variant of the PatchMatch-Stereo-algorithm that differs from current approaches in two ways: First it supports the equirectangular camera model while other solutions are limited to the pinhole camera model. Second it is optimized for low latency while keeping a high level of completeness and accuracy. To achieve this it operates only on small sequences of keyframes, but employs techniques to compensate for the potential loss of accuracy due to the limited number of frames. Results demonstrate that dense 3d reconstruction is possible on a consumer grade laptop with a recent mobile GPU and that it is possible with improved accuracy and completeness over common offline-MVS solutions with comparable quality settings.
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策略分解(PODEC)是一个框架,在将政策推导到最佳控制问题时,可以减少维度的诅咒。对于给定的系统表示形式,即描述系统的状态变量和控制输入,PODEC生成了分解所有控制输入的策略的策略。因此,不同输入的策略以脱钩或级联的方式得出,作为状态变量某些子集的函数,导致计算减少。但是,系统表示的选择至关重要,因为它决定了由此产生的策略的次优性。我们提出了一种启发式方法,可以找到更适合分解的表示形式。我们的方法是基于这样的观察结果,即每个分解都以最佳成本为代价,并且已经导致稀疏最佳策略的表示形式在产生的政策中实现了稀疏模式,这可能会产生较低的次级优势的分解。由于尚不清楚最佳策略,我们构建了一个剥夺其LQR近似值的系统表示。对于简化的双头,4个自由度的操纵器和四轮驱动器,我们发现分解物比Vanilla Podec确定的轨迹成本降低了10%。此外,与最先进的强化学习算法获得的政策相比,分解政策产生的轨迹的成本大大降低。
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韵律在言语交流中起着至关重要的作用。韵律的声明已被广泛研究。但是,韵律特征不仅被视而不见,而且在视觉上是基于头部和面部运动的视觉上。本报告的目的是提出一种使用虚拟现实检查视听韵律的方法。我们表明,基于虚拟人的动画提供了与真正说话者视频录音相似的运动提示。虚拟现实的使用开辟了新的途径,以检查口头交流的多模式效应。我们讨论了研究人工耳蜗听众中韵律感知的框架中的方法。
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多机器人导航是一项具有挑战性的任务,其中必须在动态环境中同时协调多个机器人。我们应用深入的加固学习(DRL)来学习分散的端到端策略,该政策将原始传感器数据映射到代理的命令速度。为了使政策概括,培训是在不同的环境和场景中进行的。在常见的多机器人场景中测试和评估了学识渊博的政策,例如切换一个地方,交叉路口和瓶颈情况。此策略使代理可以从死端恢复并浏览复杂的环境。
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气候变化导致越来越多的极端天气事件,例如大雨和洪水。该技术报告涉及一个问题,即在使用无人驾驶汽车(无人机)(即2021年7月在中欧的洪水中,更具体地说,更具体地说是在Erftstadt / Blessem)的洪水灾害期间如何更好,更快地提供洪水灾难的当前信息。一方面,将无人机用于实时观察和定期检查洪水边缘,另一方面,用于系统数据采集,以便使用Motion和Multiview Stereo的结构来计算3D模型。嵌入GIS应用程序中的3D模型是系统探索和决策支持,以部署其他较小的无人机和救援力量的计划。通过自主曲折航班对无人机进行系统的数据采集提供了高分辨率图像,这些图像在15分钟内通过专用机器人命令车辆(ROBLW)计算为周围区域的地理参与3D模型。从连续几天从3D模型中提取的高分辨率高程轮廓的比较,水位的变化变得可见。该信息使应急管理能够计划对建筑物的进一步检查,并在现场寻找失踪人员。
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对于痴呆症筛查和监测,标准化测试在临床常规中起着关键作用,因为它们旨在通过测量各种认知任务的性能来最大程度地降低主观性。在本文中,我们报告了一项由半标准化病史组成的研究,然后进行了两个标准化的神经心理学测试,即SKT和CERAD-NB。这些测试包括基本任务,例如命名对象,学习单词列表,以及广泛使用的工具,例如MMSE。大多数任务是在口头上执行的,因此应适用于基于成绩单的自动评分。对于第一批30例患者,我们根据手动和自动转录分析了专家手动评估与自动评估之间的相关性。对于SKT和CERAD-NB,我们都可以使用手动笔录观察到高至完美的相关性。对于某些相关性较低的任务,自动评分比人类参考更严格,因为它仅限于音频。使用自动转录,相关性降低,并且与识别精度有关;但是,我们仍然观察到高达0.98(SKT)和0.85(CERAD-NB)的高相关性。我们表明,使用单词替代方案有助于减轻识别错误,并随后改善与专家分数的相关性。
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标准化测试在检测认知障碍中起着至关重要的作用。先前的工作表明,使用标准化图片描述任务中的音频数据可以自动检测认知障碍。提出的研究超出了这一点,评估了我们对来自两个标准化神经心理学测试的数据,即德国SKT和德国版本的CERAD-NB,以及患者与心理学家之间的半结构化临床访谈。对于测试,我们关注三个子测试的语音记录:阅读数字(SKT 3),干扰(SKT 7)和口头流利度(Cerad-NB 1)。我们表明,标准化测试的声学特征可用于可靠地区分非受损的人的认知受损个体。此外,我们提供的证据表明,即使是从访谈的随机语音样本中提取的特征也可能是认知障碍的歧视者。在我们的基线实验中,我们使用开米的功能和支持向量机分类器。在改进的设置中,我们表明使用WAV2VEC 2.0功能,我们可以达到高达85%的精度。
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量子技术有可能彻底改变我们如何获取和处理实验数据以了解物理世界。一种实验设置,将来自物理系统的数据转换为稳定的量子存储器,以及使用量子计算机的数据的处理可以具有显着的优点,这些实验可以具有测量物理系统的传统实验,并且使用经典计算机处理结果。我们证明,在各种任务中,量子机器可以从指数较少的实验中学习而不是传统实验所需的实验。指数优势在预测物理系统的预测属性中,对噪声状态进行量子主成分分析,以及学习物理动态的近似模型。在一些任务中,实现指数优势所需的量子处理可能是适度的;例如,可以通过仅处理系统的两个副本来同时了解许多非信息可观察。我们表明,可以使用当今相对嘈杂的量子处理器实现大量超导QUBITS和1300个量子门的实验。我们的结果突出了量子技术如何能够实现强大的新策略来了解自然。
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