有效的点云压缩对于虚拟和混合现实,自动驾驶和文化遗产等应用至关重要。在本文中,我们为动态点云几何压缩提出了一个基于深度学习的框架间编码方案。我们提出了一种有损的几何压缩方案,该方案通过使用新的预测网络,使用先前的框架来预测当前帧的潜在表示。我们提出的网络利用稀疏的卷积使用层次多尺度3D功能学习来使用上一个帧编码当前帧。我们在目标坐标上采用卷积来将上一个帧的潜在表示为当前帧的降采样坐标,以预测当前帧的特征嵌入。我们的框架通过使用学习的概率分解熵模型来压缩预测功能的残差和实际特征。在接收器中,解码器层次结构通过逐步重新嵌入功能嵌入来重建当前框架。我们将我们的模型与基于最先进的视频点云压缩(V-PCC)和基于几何的点云压缩(G-PCC)方案进行了比较,该方案由Moving Picture Experts Group(MPEG)标准化。我们的方法实现了91%以上的BD率Bjontegaard三角洲率)降低了G-PCC,针对V-PCC框架内编码模式的BD率降低了62%以上,而对于V-PC。使用HEVC,基于PCC P框架的框架间编码模式。
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最近,大型高质量的公共数据集导致了卷积神经网络的发展,这些神经网络可以在专家病理学家水平上检测乳腺癌的淋巴结转移。许多癌症,无论起源地点如何,都可以转移到淋巴结。但是,收集和注释每种癌症类型的高量,高质量数据集都是具有挑战性的。在本文中,我们研究了如何在多任务设置中最有效地利用现有的高质量数据集,以实现紧密相关的任务。具体而言,我们将探索不同的训练和领域适应策略,包括预防灾难性遗忘,用于结肠和头颈癌症转移淋巴结中的灾难性遗忘。我们的结果表明,两项癌症转移检测任务的最新性能。此外,我们显示了从一种癌症类型到另一种癌症的反复适应以获得多任务转移检测网络的有效性。最后,我们表明,利用现有的高质量数据集可以显着提高新目标任务的性能,并且可以使用正则化有效地减轻灾难性遗忘。
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放射线学使用定量医学成像特征来预测临床结果。目前,在新的临床应用中,必须通过启发式试验和纠正过程手动完成各种可用选项的最佳放射组方法。在这项研究中,我们提出了一个框架,以自动优化每个应用程序的放射线工作流程的构建。为此,我们将放射线学作为模块化工作流程,并为每个组件包含大量的常见算法。为了优化每个应用程序的工作流程,我们使用随机搜索和结合使用自动化机器学习。我们在十二个不同的临床应用中评估我们的方法,从而在曲线下导致以下区域:1)脂肪肉瘤(0.83); 2)脱粘型纤维瘤病(0.82); 3)原发性肝肿瘤(0.80); 4)胃肠道肿瘤(0.77); 5)结直肠肝转移(0.61); 6)黑色素瘤转移(0.45); 7)肝细胞癌(0.75); 8)肠系膜纤维化(0.80); 9)前列腺癌(0.72); 10)神经胶质瘤(0.71); 11)阿尔茨海默氏病(0.87);和12)头颈癌(0.84)。我们表明,我们的框架具有比较人类专家的竞争性能,优于放射线基线,并且表现相似或优于贝叶斯优化和更高级的合奏方法。最后,我们的方法完全自动优化了放射线工作流的构建,从而简化了在新应用程序中对放射线生物标志物的搜索。为了促进可重复性和未来的研究,我们公开发布了六个数据集,框架的软件实施以及重现这项研究的代码。
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Deep learning algorithms, in particular convolutional networks, have rapidly become a methodology of choice for analyzing medical images. This paper reviews the major deep learning concepts pertinent to medical image analysis and summarizes over 300 contributions to the field, most of which appeared in the last year. We survey the use of deep learning for image classification, object detection, segmentation, registration, and other tasks. Concise overviews are provided of studies per application area: neuro, retinal, pulmonary, digital pathology, breast, cardiac, abdominal, musculoskeletal. We end with a summary of the current state-of-the-art, a critical discussion of open challenges and directions for future research.
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自动生物医学图像分析的领域至关重要地取决于算法验证的可靠和有意义的性能指标。但是,当前的度量使用通常是不明智的,并且不能反映基本的域名。在这里,我们提出了一个全面的框架,该框架指导研究人员以问题意识的方式选择绩效指标。具体而言,我们专注于生物医学图像分析问题,这些问题可以解释为图像,对象或像素级别的分类任务。该框架首先编译域兴趣 - 目标结构 - ,数据集和算法与输出问题相关的属性的属性与问题指纹相关,同时还将其映射到适当的问题类别,即图像级分类,语义分段,实例,实例细分或对象检测。然后,它指导用户选择和应用一组适当的验证指标的过程,同时使他们意识到与个人选择相关的潜在陷阱。在本文中,我们描述了指标重新加载推荐框架的当前状态,目的是从图像分析社区获得建设性的反馈。当前版本是在由60多个图像分析专家的国际联盟中开发的,将在社区驱动的优化之后公开作为用户友好的工具包提供。
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尽管自动图像分析的重要性不断增加,但最近的元研究揭示了有关算法验证的主要缺陷。性能指标对于使用的自动算法的有意义,客观和透明的性能评估和验证尤其是关键,但是在使用特定的指标进行给定的图像分析任务时,对实际陷阱的关注相对较少。这些通常与(1)无视固有的度量属性,例如在存在类不平衡或小目标结构的情况下的行为,(2)无视固有的数据集属性,例如测试的非独立性案例和(3)无视指标应反映的实际生物医学领域的兴趣。该动态文档的目的是说明图像分析领域通常应用的性能指标的重要局限性。在这种情况下,它重点介绍了可以用作图像级分类,语义分割,实例分割或对象检测任务的生物医学图像分析问题。当前版本是基于由全球60多家机构的国际图像分析专家进行的关于指标的Delphi流程。
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We present the interpretable meta neural ordinary differential equation (iMODE) method to rapidly learn generalizable (i.e., not parameter-specific) dynamics from trajectories of multiple dynamical systems that vary in their physical parameters. The iMODE method learns meta-knowledge, the functional variations of the force field of dynamical system instances without knowing the physical parameters, by adopting a bi-level optimization framework: an outer level capturing the common force field form among studied dynamical system instances and an inner level adapting to individual system instances. A priori physical knowledge can be conveniently embedded in the neural network architecture as inductive bias, such as conservative force field and Euclidean symmetry. With the learned meta-knowledge, iMODE can model an unseen system within seconds, and inversely reveal knowledge on the physical parameters of a system, or as a Neural Gauge to "measure" the physical parameters of an unseen system with observed trajectories. We test the validity of the iMODE method on bistable, double pendulum, Van der Pol, Slinky, and reaction-diffusion systems.
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Recent advancements in sensing and communication facilitate obtaining high-frequency real-time data from various physical systems like power networks, climate systems, biological networks, etc. However, since the data are recorded by physical sensors, it is natural that the obtained data is corrupted by measurement noise. In this paper, we present a novel algorithm for online real-time learning of dynamical systems from noisy time-series data, which employs the Robust Koopman operator framework to mitigate the effect of measurement noise. The proposed algorithm has three main advantages: a) it allows for online real-time monitoring of a dynamical system; b) it obtains a linear representation of the underlying dynamical system, thus enabling the user to use linear systems theory for analysis and control of the system; c) it is computationally fast and less intensive than the popular Extended Dynamic Mode Decomposition (EDMD) algorithm. We illustrate the efficiency of the proposed algorithm by applying it to identify the Van der Pol oscillator, the IEEE 68 bus system, and a ring network of Van der Pol oscillators.
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We introduce PRISM, a method for real-time filtering in a probabilistic generative model of agent motion and visual perception. Previous approaches either lack uncertainty estimates for the map and agent state, do not run in real-time, do not have a dense scene representation or do not model agent dynamics. Our solution reconciles all of these aspects. We start from a predefined state-space model which combines differentiable rendering and 6-DoF dynamics. Probabilistic inference in this model amounts to simultaneous localisation and mapping (SLAM) and is intractable. We use a series of approximations to Bayesian inference to arrive at probabilistic map and state estimates. We take advantage of well-established methods and closed-form updates, preserving accuracy and enabling real-time capability. The proposed solution runs at 10Hz real-time and is similarly accurate to state-of-the-art SLAM in small to medium-sized indoor environments, with high-speed UAV and handheld camera agents (Blackbird, EuRoC and TUM-RGBD).
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Strategic test allocation plays a major role in the control of both emerging and existing pandemics (e.g., COVID-19, HIV). Widespread testing supports effective epidemic control by (1) reducing transmission via identifying cases, and (2) tracking outbreak dynamics to inform targeted interventions. However, infectious disease surveillance presents unique statistical challenges. For instance, the true outcome of interest - one's positive infectious status, is often a latent variable. In addition, presence of both network and temporal dependence reduces the data to a single observation. As testing entire populations regularly is neither efficient nor feasible, standard approaches to testing recommend simple rule-based testing strategies (e.g., symptom based, contact tracing), without taking into account individual risk. In this work, we study an adaptive sequential design involving n individuals over a period of {\tau} time-steps, which allows for unspecified dependence among individuals and across time. Our causal target parameter is the mean latent outcome we would have obtained after one time-step, if, starting at time t given the observed past, we had carried out a stochastic intervention that maximizes the outcome under a resource constraint. We propose an Online Super Learner for adaptive sequential surveillance that learns the optimal choice of tests strategies over time while adapting to the current state of the outbreak. Relying on a series of working models, the proposed method learns across samples, through time, or both: based on the underlying (unknown) structure in the data. We present an identification result for the latent outcome in terms of the observed data, and demonstrate the superior performance of the proposed strategy in a simulation modeling a residential university environment during the COVID-19 pandemic.
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