3D扫描技术的最新进展使得在数字双胞胎,远程检验和逆向工程等各种工业应用中部署了3D模型。尽管他们不断变化的性能,3D扫描仪,仍然在所获取的密集模型中引入噪音和伪影。在这项工作中,我们为密集3D扫描工业模型提出了一种快速且坚固的去噪方法。所提出的方法采用条件变化自动化器来有效地滤除面正线。在滑动补丁设置中执行培训和推理,从而减少所需培训数据和执行时间的大小。我们使用3D扫描和CAD模型进行了广泛的评估研究。结果验证了合理的去噪结果,与其他最先进的方法相比,展示了类似或更高的重建准确性。具体地,对于具有超过1E4面的3D模型,所示的管道是具有等效重建误差的方法的两倍。
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网状denoising是数字几何处理中的基本问题。它试图消除表面噪声,同时尽可能准确地保留表面固有信号。尽管传统的智慧是基于专门的先验来平稳表面的,但基于学习的方法在概括和自动化方面取得了巨大的成功。在这项工作中,我们对网格denoising的进步进行了全面的综述,其中包含传统的几何方法和最近的基于学习的方法。首先,要熟悉读者的denoising任务,我们总结了网格denoising中的四个常见问题。然后,我们提供了两种现有的脱氧方法的分类。此外,分别详细介绍和分析了三个重要类别,包括优化,过滤器和基于数据驱动的技术。说明了定性和定量比较,以证明最先进的去核方法的有效性。最后,指出未来工作的潜在方向来解决这些方法的共同问题。这项工作还建立了网格denoising基准测试,未来的研究人员将通过最先进的方法轻松方便地评估其方法。
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Intelligent mesh generation (IMG) refers to a technique to generate mesh by machine learning, which is a relatively new and promising research field. Within its short life span, IMG has greatly expanded the generalizability and practicality of mesh generation techniques and brought many breakthroughs and potential possibilities for mesh generation. However, there is a lack of surveys focusing on IMG methods covering recent works. In this paper, we are committed to a systematic and comprehensive survey describing the contemporary IMG landscape. Focusing on 110 preliminary IMG methods, we conducted an in-depth analysis and evaluation from multiple perspectives, including the core technique and application scope of the algorithm, agent learning goals, data types, targeting challenges, advantages and limitations. With the aim of literature collection and classification based on content extraction, we propose three different taxonomies from three views of key technique, output mesh unit element, and applicable input data types. Finally, we highlight some promising future research directions and challenges in IMG. To maximize the convenience of readers, a project page of IMG is provided at \url{https://github.com/xzb030/IMG_Survey}.
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卷积神经网络(CNNS)在2D计算机视觉中取得了很大的突破。然而,它们的不规则结构使得难以在网格上直接利用CNNS的潜力。细分表面提供分层多分辨率结构,其中闭合的2 - 歧管三角网格中的每个面正恰好邻近三个面。本文推出了这两种观察,介绍了具有环形细分序列连接的3D三角形网格的创新和多功能CNN框架。在2D图像中的网格面和像素之间进行类比允许我们呈现网状卷积操作者以聚合附近面的局部特征。通过利用面部街区,这种卷积可以支持标准的2D卷积网络概念,例如,可变内核大小,步幅和扩张。基于多分辨率层次结构,我们利用汇集层,将四个面均匀地合并成一个和上采样方法,该方法将一个面分为四个。因此,许多流行的2D CNN架构可以容易地适应处理3D网格。可以通过自我参数化来回收具有任意连接的网格,以使循环细分序列连接,使子变量是一般的方法。广泛的评估和各种应用展示了SubDIVNet的有效性和效率。
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Learned 3D representations of human faces are useful for computer vision problems such as 3D face tracking and reconstruction from images, as well as graphics applications such as character generation and animation. Traditional models learn a latent representation of a face using linear subspaces or higher-order tensor generalizations. Due to this linearity, they can not capture extreme deformations and nonlinear expressions. To address this, we introduce a versatile model that learns a non-linear representation of a face using spectral convolutions on a mesh surface. We introduce mesh sampling operations that enable a hierarchical mesh representation that captures non-linear variations in shape and expression at multiple scales within the model. In a variational setting, our model samples diverse realistic 3D faces from a multivariate Gaussian distribution. Our training data consists of 20,466 meshes of extreme expressions captured over 12 different subjects. Despite limited training data, our trained model outperforms state-of-the-art face models with 50% lower reconstruction error, while using 75% fewer parameters. We show that, replacing the expression space of an existing state-of-theart face model with our model, achieves a lower reconstruction error. Our data, model and code are available at http://coma.is.tue.mpg.de/.
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作为3D数据的流行表示,点云可能包含噪声,并且需要在使用前过滤。现有点云过滤方法不能在滤波输出中保留尖锐的功能或导致不均匀的点分布。为了解决这个问题,本文介绍了一种点云过滤方法,在过滤期间考虑点分布和功能保存。关键的想法是将排斥项包含在能量最小化中的数据项。排斥项负责点分布,而数据项是在保留几何特征的同时近似噪声表面。该方法能够处理具有微尺度特征和尖锐功能的型号。广泛的实验表明,我们的方法在几秒钟内以更均匀的点分布产生更好的结果,更均匀的点分布(5.8美元\ times10 ^ {5} $倒角距离)。
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从嘈杂的点云中恢复高质量的表面,称为点云降级,是几何处理中的一个基本而又具有挑战性的问题。大多数现有方法要么直接将嘈杂的输入或过滤器原始正态变为更新点位置。由点云降解和正常过滤之间的基本相互作用的动机,我们从多任务的角度重新访问点云,并提出一个名为PCDNF的端到端网络,以通过关节正常滤波来denoise点云。特别是,我们引入了一项辅助正常过滤任务,以帮助整体网络更有效地消除噪声,同时更准确地保留几何特征。除了整体体系结构外,我们的网络还具有两个新型模块。一方面,为了提高降噪性能,我们设计了一种形状感知的选择器,以全面考虑学习点,正常特征和几何学先验,以构建特定点的潜在切线空间表示。另一方面,点特征更适合描述几何细节,正常特征更有利于表示几何结构(例如,边缘和角落)。结合点和正常特征使我们能够克服它们的弱点。因此,我们设计一个功能改进模块,以融合点和正常功能,以更好地恢复几何信息。广泛的评估,比较和消融研究表明,所提出的方法在点云降解和正常过滤方面优于最先进的方法。
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三角形网格是3D对象的最受欢迎的表示,但是许多网格表面都包含拓扑奇异性,代表了显示或进一步正确处理它们的挑战。这样的奇异性是通过扫描过程或通过变形转换(例如偏离设置)创建的网格表面中存在的自我交流。网格折叠包括一个特殊的筛网表面自相交的情况,其中3D模型的面相交并逆转,相对于网格表面的展开部分。提出了一种识别和修复网格表面折叠的新方法,该方法利用了折叠的结构特征,以有效地检测折叠区域。检测后,卸下折叠,并根据3D模型的几何形状填补了折叠的任何空白。所提出的方法直接适用于简单的网格表面表示,而它不执行3D网格的任何嵌入(即Voxelization,投影)。该方法的目标是以最有效的方式以保留原始结构的方式促进网格退化程序。
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The underlying dynamics and patterns of 3D surface meshes deforming over time can be discovered by unsupervised learning, especially autoencoders, which calculate low-dimensional embeddings of the surfaces. To study the deformation patterns of unseen shapes by transfer learning, we want to train an autoencoder that can analyze new surface meshes without training a new network. Here, most state-of-the-art autoencoders cannot handle meshes of different connectivity and therefore have limited to no generalization capacities to new meshes. Also, reconstruction errors strongly increase in comparison to the errors for the training shapes. To address this, we propose a novel spectral CoSMA (Convolutional Semi-Regular Mesh Autoencoder) network. This patch-based approach is combined with a surface-aware training. It reconstructs surfaces not presented during training and generalizes the deformation behavior of the surfaces' patches. The novel approach reconstructs unseen meshes from different datasets in superior quality compared to state-of-the-art autoencoders that have been trained on these shapes. Our transfer learning errors on unseen shapes are 40% lower than those from models learned directly on the data. Furthermore, baseline autoencoders detect deformation patterns of unseen mesh sequences only for the whole shape. In contrast, due to the employed regional patches and stable reconstruction quality, we can localize where on the surfaces these deformation patterns manifest.
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3D表面的复杂性通常会导致表面降解中的尖端点云降解(PCD)模型,包括残余噪声,错误地被错误的几何细节。尽管使用多尺度贴片来编码点的几何形状已成为PCD中的共同智慧,但我们发现,根据有关嘈杂点的几何信息,提取的多尺度特征的简单聚合无法自适应地利用适当的比例信息。它导致表面降解,尤其是对于接近边缘和复杂曲面上的点的点。我们提出了一个有趣的问题 - 如果采用多尺度的几何感知信息来指导网络利用多尺度信息,可以消除严重的表面降解问题吗?为了回答它,我们提出了一个为多尺度补丁定制的多关型denoising网络(MODNET)。首先,我们通过补丁功能编码器提取三个量表补丁的低级特征。其次,一个多尺度感知模块设计用于嵌入每个刻度功能的多尺度几何信息,并回归多尺度权重,以指导多关机deoising位移。第三,一个多偏移解码器会回归三个比例偏移,这些缩放量偏移以多尺度权重为指导,以通过适应性加权来预测最终位移。实验表明,我们的方法在合成和实范围的数据集上都实现了新的最新性能。
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点云过滤和正常估计是3D场中的两个基本研究问题。现有方法通常会单独执行正常的估计和过滤,并且经常表现出对噪声和/或无法保留尖锐几何特征(例如角和边缘)的敏感性。在本文中,我们提出了一种新颖的深度学习方法,以共同估计正态和过滤点云。我们首先引入了一个基于3D补丁的对比学习框架,并以噪声损坏为增强,以训练能够生成点云斑块的忠实表示的功能编码器,同时保持噪音的强大功能。这些表示由简单的回归网络消耗,并通过新的关节损失进行监督,同时估算用于过滤贴片中心的点正常和位移。实验结果表明,我们的方法同时支持这两个任务,并保留尖锐的功能和细节。通常,它在这两个任务上都胜过最先进的技术。
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培训和测试监督对象检测模型需要大量带有地面真相标签的图像。标签定义图像中的对象类及其位置,形状以及可能的其他信息,例如姿势。即使存在人力,标签过程也非常耗时。我们引入了一个新的标签工具,用于2D图像以及3D三角网格:3D标记工具(3DLT)。这是一个独立的,功能丰富和跨平台软件,不需要安装,并且可以在Windows,MacOS和基于Linux的发行版上运行。我们不再像当前工具那样在每个图像上分别标记相同的对象,而是使用深度信息从上述图像重建三角形网格,并仅在上述网格上标记一次对象。我们使用注册来简化3D标记,离群值检测来改进2D边界框的计算和表面重建,以将标记可能性扩展到大点云。我们的工具经过最先进的方法测试,并且在保持准确性和易用性的同时,它极大地超过了它们。
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点云降级旨在从噪音和异常值损坏的原始观察结果中恢复清洁点云,同时保留细粒细节。我们提出了一种新型的基于深度学习的DeNoising模型,该模型结合了正常的流量和噪声解散技术,以实现高降解精度。与提取点云特征以进行点校正的现有作品不同,我们从分布学习和特征分离的角度制定了denoising过程。通过将嘈杂的点云视为清洁点和噪声的联合分布,可以从将噪声对应物从潜在点表示中解​​散出来,而欧几里得和潜在空间之间的映射是通过标准化流量来建模的。我们评估了具有各种噪声设置的合成3D模型和现实世界数据集的方法。定性和定量结果表明,我们的方法表现优于先前的最先进的基于深度学习的方法。
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Geometric rectification of images of distorted documents finds wide applications in document digitization and Optical Character Recognition (OCR). Although smoothly curved deformations have been widely investigated by many works, the most challenging distortions, e.g. complex creases and large foldings, have not been studied in particular. The performance of existing approaches, when applied to largely creased or folded documents, is far from satisfying, leaving substantial room for improvement. To tackle this task, knowledge about document rectification should be incorporated into the computation, among which the developability of 3D document models and particular textural features in the images, such as straight lines, are the most essential ones. For this purpose, we propose a general framework of document image rectification in which a computational isometric mapping model is utilized for expressing a 3D document model and its flattening in the plane. Based on this framework, both model developability and textural features are considered in the computation. The experiments and comparisons to the state-of-the-art approaches demonstrated the effectiveness and outstanding performance of the proposed method. Our method is also flexible in that the rectification results can be enhanced by any other methods that extract high-quality feature lines in the images.
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最近的工作建模3D开放表面培训深度神经网络以近似无符号距离字段(UDF)并隐含地代表形状。要将此表示转换为显式网格,它们要么使用计算上昂贵的方法来对表面的致密点云采样啮合,或者通过将其膨胀到符号距离字段(SDF)中来扭曲表面。相比之下,我们建议直接将深度UDFS直接以延伸行进立方体的开放表面,通过本地检测表面交叉。我们的方法是幅度的序列,比啮合致密点云,比膨胀开口表面更准确。此外,我们使我们的表面提取可微分,并显示它可以帮助稀疏监控信号。
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Computational fluid dynamics (CFD) is a valuable asset for patient-specific cardiovascular-disease diagnosis and prognosis, but its high computational demands hamper its adoption in practice. Machine-learning methods that estimate blood flow in individual patients could accelerate or replace CFD simulation to overcome these limitations. In this work, we consider the estimation of vector-valued quantities on the wall of three-dimensional geometric artery models. We employ group-equivariant graph convolution in an end-to-end SE(3)-equivariant neural network that operates directly on triangular surface meshes and makes efficient use of training data. We run experiments on a large dataset of synthetic coronary arteries and find that our method estimates directional wall shear stress (WSS) with an approximation error of 7.6% and normalised mean absolute error (NMAE) of 0.4% while up to two orders of magnitude faster than CFD. Furthermore, we show that our method is powerful enough to accurately predict transient, vector-valued WSS over the cardiac cycle while conditioned on a range of different inflow boundary conditions. These results demonstrate the potential of our proposed method as a plugin replacement for CFD in the personalised prediction of hemodynamic vector and scalar fields.
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近年来,由于其表达力和灵活性,神经隐式表示在3D重建中获得了普及。然而,神经隐式表示的隐式性质导致缓慢的推理时间并且需要仔细初始化。在本文中,我们重新审视经典且无处不在的点云表示,并使用泊松表面重建(PSR)的可分辨率配方引入可分化的点对网格层,其允许给予定向的GPU加速的指示灯的快速解决方案点云。可微分的PSR层允许我们通过隐式指示器字段有效地和分散地桥接与3D网格的显式3D点表示,从而实现诸如倒角距离的表面重建度量的端到端优化。因此,点和网格之间的这种二元性允许我们以面向点云表示形状,这是显式,轻量级和富有表现力的。与神经内隐式表示相比,我们的形状 - 点(SAP)模型更具可解释,轻量级,并通过一个级别加速推理时间。与其他显式表示相比,如点,补丁和网格,SA​​P产生拓扑无关的水密歧管表面。我们展示了SAP对无知点云和基于学习的重建的表面重建任务的有效性。
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Point Cloud升级旨在从给定的稀疏中产生密集的点云,这是一项具有挑战性的任务,这是由于点集的不规则和无序的性质。为了解决这个问题,我们提出了一种新型的基于深度学习的模型,称为PU-Flow,该模型结合了正常的流量和权重预测技术,以产生均匀分布在基础表面上的致密点。具体而言,我们利用标准化流的可逆特征来转换欧几里得和潜在空间之间的点,并将UPSMPLING过程作为潜在空间中相邻点的集合,从本地几何环境中自适应地学习。广泛的实验表明,我们的方法具有竞争力,并且在大多数测试用例中,它在重建质量,近距到表面的准确性和计算效率方面的表现优于最先进的方法。源代码将在https://github.com/unknownue/pu-flow上公开获得。
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我们提出了Cortexode,这是一种用于皮质表面重建的深度学习框架。 Cortexode利用神经普通微分方程(ODE)通过学习差异流来使输入表面变形为目标形状。表面上的点的轨迹将其建模为ODE,其中其坐标的衍生物通过可学习的Lipschitz-Conluble变形网络进行了参数化。这为预防自身干扰提供了理论保证。 Cortexode可以集成到基于自动学习的管道上,该管道可在不到5秒钟内有效地重建皮质表面。该管道利用3D U-NET来预测大脑磁共振成像(MRI)扫描的白质分割,并进一步生成代表初始表面的签名距离函数。引入快速拓扑校正以确保对球体的同构。遵循等曲面提取步骤,对两个Cortexode模型进行了训练,以分别将初始表面变形为白质和曲面。在包括新生儿(25-45周),年轻人(22-36岁)和老年受试者(55-90岁)(55-90岁)(55-90岁)的各个年龄段的大规模神经图像数据集上对拟议的管道进行评估。我们的实验表明,与常规处理管道相比,基于Cortexode的管道可以达到平均几何误差的平均几何误差小于0.2mm的平均几何误差。
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Recent approaches to drape garments quickly over arbitrary human bodies leverage self-supervision to eliminate the need for large training sets. However, they are designed to train one network per clothing item, which severely limits their generalization abilities. In our work, we rely on self-supervision to train a single network to drape multiple garments. This is achieved by predicting a 3D deformation field conditioned on the latent codes of a generative network, which models garments as unsigned distance fields. Our pipeline can generate and drape previously unseen garments of any topology, whose shape can be edited by manipulating their latent codes. Being fully differentiable, our formulation makes it possible to recover accurate 3D models of garments from partial observations -- images or 3D scans -- via gradient descent. Our code will be made publicly available.
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