精确地重建由单个图像的各种姿势和服装引起的精确复杂的人类几何形状非常具有挑战性。最近，基于像素对齐的隐式函数（PIFU）的作品已迈出了一步，并在基于图像的3D人数数字化上实现了最先进的保真度。但是，PIFU的培训在很大程度上取决于昂贵且有限的3D地面真相数据（即合成数据），从而阻碍了其对更多样化的现实世界图像的概括。在这项工作中，我们提出了一个名为selfpifu的端到端自我监督的网络，以利用丰富和多样化的野外图像，在对无约束的内部图像进行测试时，在很大程度上改善了重建。 SelfPifu的核心是深度引导的体积/表面感知的签名距离领域（SDF）学习，它可以自欺欺人地学习PIFU，而无需访问GT网格。整个框架由普通估计器，深度估计器和基于SDF的PIFU组成，并在训练过程中更好地利用了额外的深度GT。广泛的实验证明了我们自我监督框架的有效性以及使用深度作为输入的优越性。在合成数据上，与PIFUHD相比，我们的交叉点（IOU）达到93.5％，高18％。对于野外图像，我们对重建结果进行用户研究，与其他最先进的方法相比，我们的结果的选择率超过68％。

We propose a differentiable sphere tracing algorithm to bridge the gap between inverse graphics methods and the recently proposed deep learning based implicit signed distance function. Due to the nature of the implicit function, the rendering process requires tremendous function queries, which is particularly problematic when the function is represented as a neural network. We optimize both the forward and backward passes of our rendering layer to make it run efficiently with affordable memory consumption on a commodity graphics card. Our rendering method is fully differentiable such that losses can be directly computed on the rendered 2D observations, and the gradients can be propagated backwards to optimize the 3D geometry. We show that our rendering method can effectively reconstruct accurate 3D shapes from various inputs, such as sparse depth and multi-view images, through inverse optimization. With the geometry based reasoning, our 3D shape prediction methods show excellent generalization capability and robustness against various noises. * Work done while Shaohui Liu was an academic guest at ETH Zurich.

With the success of neural volume rendering in novel view synthesis, neural implicit reconstruction with volume rendering has become popular. However, most methods optimize per-scene functions and are unable to generalize to novel scenes. We introduce VolRecon, a generalizable implicit reconstruction method with Signed Ray Distance Function (SRDF). To reconstruct with fine details and little noise, we combine projection features, aggregated from multi-view features with a view transformer, and volume features interpolated from a coarse global feature volume. A ray transformer computes SRDF values of all the samples along a ray to estimate the surface location, which are used for volume rendering of color and depth. Extensive experiments on DTU and ETH3D demonstrate the effectiveness and generalization ability of our method. On DTU, our method outperforms SparseNeuS by about 30% in sparse view reconstruction and achieves comparable quality as MVSNet in full view reconstruction. Besides, our method shows good generalization ability on the large-scale ETH3D benchmark. Project page: https://fangjinhuawang.github.io/VolRecon.

We introduce Structured 3D Features, a model based on a novel implicit 3D representation that pools pixel-aligned image features onto dense 3D points sampled from a parametric, statistical human mesh surface. The 3D points have associated semantics and can move freely in 3D space. This allows for optimal coverage of the person of interest, beyond just the body shape, which in turn, additionally helps modeling accessories, hair, and loose clothing. Owing to this, we present a complete 3D transformer-based attention framework which, given a single image of a person in an unconstrained pose, generates an animatable 3D reconstruction with albedo and illumination decomposition, as a result of a single end-to-end model, trained semi-supervised, and with no additional postprocessing. We show that our S3F model surpasses the previous state-of-the-art on various tasks, including monocular 3D reconstruction, as well as albedo and shading estimation. Moreover, we show that the proposed methodology allows novel view synthesis, relighting, and re-posing the reconstruction, and can naturally be extended to handle multiple input images (e.g. different views of a person, or the same view, in different poses, in video). Finally, we demonstrate the editing capabilities of our model for 3D virtual try-on applications.

目前用于学习现实和可动画3D穿衣服的方法需要带有仔细控制的用户的构成3D扫描或2D图像。相比之下，我们的目标是从不受约束的姿势中只有2D人的人们学习化身。给定一组图像，我们的方法估计来自每个图像的详细3D表面，然后将它们组合成一个可动画的化身。隐式功能非常适合第一个任务，因为他们可以捕获像头发或衣服等细节。然而，目前的方法对各种人类的姿势并不稳健，并且通常会产生破碎或肢体的3D表面，缺少细节或非人形状。问题是这些方法使用对全局姿势敏感的全局特征编码器。为了解决这个问题，我们提出图标（“从正规中获得的隐式衣物人类”），它使用本地特征。图标有两个主要模块，两者都利用SMPL（-X）正文模型。首先，图标Infers详细的衣服 - 人类法线（前/后）在SMPL（-X）法线上。其次，可视性感知隐式表面回归系统产生人占用场的ISO表面。重要的是，在推断时间下，反馈回路在使用推断的布料正线改进SMPL（-X）网格之间交替，然后改装正常。给定多种姿势的多个重建帧，我们使用扫描来从中生成可动画的化身。对Agora和Cape数据集的评估显示，即使具有大量有限的培训数据，图标越优于重建中的最新状态。另外，它对分布外样品进行更强大，例如，野外的姿势/图像和帧外裁剪。图标从野外图像中迈向强大的3D穿上人体重建。这使得能够使用个性化和天然姿势依赖布变形来直接从视频创建化身。

在许多计算机视觉和图形应用程序中，从2D图像重建3D室内场景是一项重要任务。这项任务中的一个主要挑战是，典型的室内场景中的无纹理区域使现有方法难以产生令人满意的重建结果。我们提出了一种名为Neuris的新方法，以高质量地重建室内场景。 Neuris的关键思想是将估计的室内场景正常整合为神经渲染框架中的先验，以重建大型无纹理形状，并且重要的是，以适应性的方式进行此操作，以便重建不规则的形状，并具有很好的细节。 。具体而言，我们通过检查优化过程中重建的多视图一致性来评估正常先验的忠诚。只有被接受为忠实的正常先验才能用于3D重建，通常发生在平滑形状的区域中，可能具有弱质地。但是，对于那些具有小物体或薄结构的区域，普通先验通常不可靠，我们只能依靠输入图像的视觉特征，因为此类区域通常包含相对较丰富的视觉特征（例如，阴影变化和边界轮廓）。广泛的实验表明，在重建质量方面，Neuris明显优于最先进的方法。

The combination of artist-curated scans, and deep implicit functions (IF), is enabling the creation of detailed, clothed, 3D humans from images. However, existing methods are far from perfect. IF-based methods recover free-form geometry but produce disembodied limbs or degenerate shapes for unseen poses or clothes. To increase robustness for these cases, existing work uses an explicit parametric body model to constrain surface reconstruction, but this limits the recovery of free-form surfaces such as loose clothing that deviates from the body. What we want is a method that combines the best properties of implicit and explicit methods. To this end, we make two key observations: (1) current networks are better at inferring detailed 2D maps than full-3D surfaces, and (2) a parametric model can be seen as a "canvas" for stitching together detailed surface patches. ECON infers high-fidelity 3D humans even in loose clothes and challenging poses, while having realistic faces and fingers. This goes beyond previous methods. Quantitative, evaluation of the CAPE and Renderpeople datasets shows that ECON is more accurate than the state of the art. Perceptual studies also show that ECON's perceived realism is better by a large margin. Code and models are available for research purposes at https://xiuyuliang.cn/econ

我们提出了CrossHuman，这是一种新颖的方法，该方法从参数人类模型和多帧RGB图像中学习了交叉指导，以实现高质量的3D人类重建。为了恢复几何细节和纹理，即使在无形区域中，我们设计了一个重建管道，结合了基于跟踪的方法和无跟踪方法。给定一个单眼RGB序列，我们在整个序列中跟踪参数人模型，与目标框架相对应的点（体素）被参数体运动扭曲为参考框架。在参数体的几何学先验和RGB序列的空间对齐特征的指导下，稳健隐式表面被融合。此外，将多帧变压器（MFT）和一个自我监管的经过修补模块集成到框架中，以放宽参数主体的要求并帮助处理非常松散的布。与以前的作品相比，我们的十字人类可以在可见的和无形区域启用高保真的几何细节和纹理，并提高人类重建的准确性，即使在估计的不准确的参数人类模型下也是如此。实验表明我们的方法达到了最新的（SOTA）性能。

从单视图重建3D形状是一个长期的研究问题。在本文中，我们展示了深度隐式地面网络，其可以通过预测底层符号距离场来从2D图像产生高质量的细节的3D网格。除了利用全局图像特征之外，禁止2D图像上的每个3D点的投影位置，并从图像特征映射中提取本地特征。结合全球和局部特征显着提高了符合距离场预测的准确性，特别是对于富含细节的区域。据我们所知，伪装是一种不断捕获从单视图图像中存在于3D形状中存在的孔和薄结构等细节的方法。 Disn在从合成和真实图像重建的各种形状类别上实现最先进的单视性重建性能。代码可在https://github.com/xharlie/disn提供补充可以在https://xharlie.github.io/images/neUrips_2019_Supp.pdf中找到补充

在不同观点之间找到准确的对应关系是无监督的多视图立体声（MVS）的跟腱。现有方法是基于以下假设：相应的像素具有相似的光度特征。但是，在实际场景中，多视图图像观察到非斜面的表面和经验遮挡。在这项工作中，我们提出了一种新颖的方法，即神经渲染（RC-MVSNET），以解决观点之间对应关系的歧义问题。具体而言，我们施加了一个深度渲染一致性损失，以限制靠近对象表面的几何特征以减轻遮挡。同时，我们引入了参考视图综合损失，以产生一致的监督，即使是针对非兰伯特表面。关于DTU和TANKS \＆Temples基准测试的广泛实验表明，我们的RC-MVSNET方法在无监督的MVS框架上实现了最先进的性能，并对许多有监督的方法进行了竞争性能。该代码在https://github.com/上发布。 BOESE0601/RC-MVSNET

无监督的生成的虚拟人类具有各种外观和动画姿势对于创建3D人体化身和其他AR/VR应用非常重要。现有方法要么仅限于刚性对象建模，要么不生成，因此无法合成高质量的虚拟人类并使它们进行动画化。在这项工作中，我们提出了Avatargen，这是第一种不仅可以具有不同外观的非刚性人类产生的方法，而且还可以完全控制姿势和观点，同时仅需要2D图像进行训练。具体而言，它通过利用粗糙的人体模型作为代理将观察空间扭曲到规范空间下的标准头像，将最近的3D甘斯扩展到了人类的衣服。为了建模非刚性动力学，它引入了一个变形网络，以学习规范空间中的姿势依赖性变形。为了提高生成的人类化身的几何质量，它利用签名距离字段作为几何表示，从而可以从几何学学习上的身体模型中进行更直接的正则化。从这些设计中受益，我们的方法可以生成具有高质量外观和几何形状建模的动画人体化身，从而极大地表现了先前的3D gan。此外，它有能力用于许多应用，例如单视重构造，复活和文本引导的合成。代码和预培训模型将可用。

4D隐式表示中的最新进展集中在全球控制形状和运动的情况下，低维潜在向量，这很容易缺少表面细节和累积跟踪误差。尽管许多深层的本地表示显示了3D形状建模的有希望的结果，但它们的4D对应物尚不存在。在本文中，我们通过提出一个新颖的局部4D隐性代表来填补这一空白，以动态穿衣人，名为Lord，具有4D人类建模和局部代表的优点，并实现具有详细的表面变形的高保真重建，例如衣服皱纹。特别是，我们的主要见解是鼓励网络学习本地零件级表示的潜在代码，能够解释本地几何形状和时间变形。为了在测试时间进行推断，我们首先估计内部骨架运动在每个时间步中跟踪本地零件，然后根据不同类型的观察到的数据通过自动编码来优化每个部分的潜在代码。广泛的实验表明，该提出的方法具有强大的代表4D人类的能力，并且在实际应用上胜过最先进的方法，包括从稀疏点，非刚性深度融合（质量和定量）进行的4D重建。

虽然3D人类重建方法使用像素对齐的隐式功能（PIFU）开发快速，但我们观察到重建细节的质量仍然不令人满意。扁平的面部表面经常发生在基于PIFU的重建结果中。为此，我们提出了一个双重PIFU表示，以提高重建的面部细节的质量。具体地，我们利用两只MLP分别代表面部和人体的PIFU。专用于三维面重建的MLP可以提高网络容量，并降低面部细节重建的难度，如前一级PIFU表示。要解决拓扑错误，我们利用3个RGBD传感器捕获多视图RGBD数据作为网络的输入，稀疏，轻量级捕获设置。由于深度噪声严重影响重建结果，我们设计深度细化模块，以减少输入RGB图像的引导下的原始深度的噪声。我们还提出了一种自适应融合方案来熔化身体的预测占用场和面部的预测占用场，以消除其边界处的不连续性伪影。实验证明了我们在重建生动的面部细节和变形体形状方面的效果，并验证了其优于最先进的方法。

尽管通过自学意识到，基于多层感知的方法在形状和颜色恢复方面取得了令人鼓舞的结果，但在学习深层隐式表面表示方面通常会遭受沉重的计算成本。由于渲染每个像素需要一个向前的网络推断，因此合成整个图像是非常密集的。为了应对这些挑战，我们提出了一种有效的粗到精细方法，以从本文中从多视图中恢复纹理网格。具体而言，采用可区分的泊松求解器来表示对象的形状，该求解器能够产生拓扑 - 敏捷和水密表面。为了说明深度信息，我们通过最小化渲染网格与多视图立体声预测深度之间的差异来优化形状几何形状。与形状和颜色的隐式神经表示相反，我们引入了一种基于物理的逆渲染方案，以共同估计环境照明和对象的反射率，该方案能够实时呈现高分辨率图像。重建的网格的质地是从可学习的密集纹理网格中插值的。我们已经对几个多视图立体数据集进行了广泛的实验，其有希望的结果证明了我们提出的方法的功效。该代码可在https://github.com/l1346792580123/diff上找到。

Recent advances in image-based 3D human shape estimation have been driven by the significant improvement in representation power afforded by deep neural networks. Although current approaches have demonstrated the potential in real world settings, they still fail to produce reconstructions with the level of detail often present in the input images. We argue that this limitation stems primarily form two conflicting requirements; accurate predictions require large context, but precise predictions require high resolution. Due to memory limitations in current hardware, previous approaches tend to take low resolution images as input to cover large spatial context, and produce less precise (or low resolution) 3D estimates as a result. We address this limitation by formulating a multi-level architecture that is end-to-end trainable. A coarse level observes the whole image at lower resolution and focuses on holistic reasoning. This provides context to an fine level which estimates highly detailed geometry by observing higher-resolution images. We demonstrate that our approach significantly outperforms existing state-of-the-art techniques on single image human shape reconstruction by fully leveraging 1k-resolution input images.

We present a novel neural surface reconstruction method called NeuralRoom for reconstructing room-sized indoor scenes directly from a set of 2D images. Recently, implicit neural representations have become a promising way to reconstruct surfaces from multiview images due to their high-quality results and simplicity. However, implicit neural representations usually cannot reconstruct indoor scenes well because they suffer severe shape-radiance ambiguity. We assume that the indoor scene consists of texture-rich and flat texture-less regions. In texture-rich regions, the multiview stereo can obtain accurate results. In the flat area, normal estimation networks usually obtain a good normal estimation. Based on the above observations, we reduce the possible spatial variation range of implicit neural surfaces by reliable geometric priors to alleviate shape-radiance ambiguity. Specifically, we use multiview stereo results to limit the NeuralRoom optimization space and then use reliable geometric priors to guide NeuralRoom training. Then the NeuralRoom would produce a neural scene representation that can render an image consistent with the input training images. In addition, we propose a smoothing method called perturbation-residual restrictions to improve the accuracy and completeness of the flat region, which assumes that the sampling points in a local surface should have the same normal and similar distance to the observation center. Experiments on the ScanNet dataset show that our method can reconstruct the texture-less area of indoor scenes while maintaining the accuracy of detail. We also apply NeuralRoom to more advanced multiview reconstruction algorithms and significantly improve their reconstruction quality.

While deep learning has recently achieved great success on multi-view stereo (MVS), limited training data makes the trained model hard to be generalized to unseen scenarios. Compared with other computer vision tasks, it is rather difficult to collect a large-scale MVS dataset as it requires expensive active scanners and labor-intensive process to obtain ground truth 3D structures. In this paper, we introduce BlendedMVS, a novel large-scale dataset, to provide sufficient training ground truth for learning-based MVS. To create the dataset, we apply a 3D reconstruction pipeline to recover high-quality textured meshes from images of well-selected scenes. Then, we render these mesh models to color images and depth maps. To introduce the ambient lighting information during training, the rendered color images are further blended with the input images to generate the training input. Our dataset contains over 17k high-resolution images covering a variety of scenes, including cities, architectures, sculptures and small objects. Extensive experiments demonstrate that BlendedMVS endows the trained model with significantly better generalization ability compared with other MVS datasets. The dataset and pretrained models are available at https: //github.com/YoYo000/BlendedMVS.

Pixel-aligned Implicit function (PIFu): We present pixel-aligned implicit function (PIFu), which allows recovery of high-resolution 3D textured surfaces of clothed humans from a single input image (top row). Our approach can digitize intricate variations in clothing, such as wrinkled skirts and high-heels, including complex hairstyles. The shape and textures can be fully recovered including largely unseen regions such as the back of the subject. PIFu can also be naturally extended to multi-view input images (bottom row).

在这项工作中，我们为来自多视图RGB图像的3D面部重建提供了一种新方法。与以前的方法（3DMMS）构建的先前方法不同，我们的方法利用隐式表示来编码丰富的几何特征。我们的整体管道由两个主要组件组成，包括几何网络，它学习可变形的神经签名距离函数（SDF）作为3D面部表示，以及渲染网络，该渲染网络学会呈现神经SDF的面积点以匹配通过自我监督优化输入图像。要处理在测试时间的不同表达式的相同目标的野外稀疏视图输入，我们进一步提出了残余潜代码，以有效地扩展了学习的隐式面部表示的形状空间，以及新颖的视图开关丢失强制执行不同视图之间的一致性。我们在多个基准数据集上的实验结果表明，与最先进的方法相比，我们的方法优于替代基准，实现了优越的面部重建结果。

我们介绍了我们称呼STYLESDF的高分辨率，3D一致的图像和形状生成技术。我们的方法仅在单视图RGB数据上培训，并站在StyleGan2的肩部，用于图像生成，同时解决3D感知GANS中的两个主要挑战：1）RGB图像的高分辨率，视图 - 一致生成RGB图像，以及2）详细的3D形状。通过使用基于样式的2D发生器合并基于SDF的3D表示来实现这一目标。我们的3D隐式网络呈现出低分辨率的特征映射，其中基于样式的网络生成了View-Consive，1024x1024图像。值得注意的是，基于SDF的3D建模定义了详细的3D曲面，导致一致的卷渲染。在视觉和几何质量方面，我们的方法显示出更高的质量结果。