我们提出了神经链,这是一个新颖的学习框架,用于对多视图图像输入进行准确的头发几何形状和外观进行建模。从任何观点都具有高保真视图依赖性效果,可以实时渲染学习的头发模型。我们的模型可实现直观的形状和风格控制,与体积同行不同。为了实现这些特性,我们提出了一种基于神经头皮纹理的新型头发表示,该神经头皮纹理编码每个Texel位置的单个链的几何形状和外观。此外,我们基于学习的头发链的栅格化引入了一个新型的神经渲染框架。我们的神经渲染是链的和抗氧化的,使渲染视图一致且逼真。将外观与多视图几何事先结合在一起,我们首次启用了外观的联合学习和从多视图设置的显式头发几何形状。我们证明了我们的方法在各种发型的忠诚度和效率方面的功效。
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逼真的触觉需要高保真的身体建模和忠实的驾驶才能使动态合成的外观与现实无法区分。在这项工作中,我们提出了一个端到端框架,该框架解决了建模和推动真实人的全身化身方面的两个核心挑战。一个挑战是驾驶头像,同时忠实地遵守细节和动态,而这些细节和动态无法被全球低维参数化(例如身体姿势)所捕捉。我们的方法支持驾驶穿着皱纹和运动的衣服化身,而真正的驾驶表演者展出了训练语料库。与现有的全局状态表示或非参数屏幕空间方法不同,我们介绍了Texel对准功能 - 一种本地化表示,可以利用基于骨架的参数模型的结构先验和同时观察到的稀疏图像信号。另一个挑战是建模临时连贯的衣服头像,通常需要精确的表面跟踪。为了避免这种情况,我们通过将体积原语的混合物扩展到清晰的物体,提出了一种新型的体积化头像表示。通过明确合并表达,我们的方法自然而然地概括了看不见的姿势。我们还介绍了局部视点条件,从而导致了依赖视图的外观的概括。拟议的体积表示不需要高质量的网格跟踪作为先决条件,并且与基于网格的对应物相比,具有显着的质量改进。在我们的实验中,我们仔细研究了我们的设计选择,并证明了方法的功效,超过了最新方法在挑战驾驶方案方面的最新方法。
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尽管最近在开发动画全身化身方面取得了进展,但服装的现实建模(人类自我表达的核心方面之一)仍然是一个开放的挑战。最先进的物理模拟方法可以以交互速度产生现实行为的服装几何形状。但是,建模光真逼真的外观通常需要基于物理的渲染,这对于交互式应用来说太昂贵了。另一方面,数据驱动的深度外观模型能够有效地产生逼真的外观,但在合成高度动态服装的几何形状和处理具有挑战性的身体套构型方面挣扎。为此,我们通过对服装的明确建模介绍了姿势驱动的化身,这些化身表现出逼真的服装动力学和从现实世界数据中学到的逼真的外观。关键的想法是引入一个在显式几何形状之上运行的神经服装外观模型:在火车时,我们使用高保真跟踪,而在动画时期,我们依靠物理模拟的几何形状。我们的关键贡献是一个具有物理启发的外观网络,能够生成具有视图依赖性和动态阴影效果的影像逼真的外观,即使对于看不见的身体透明构型也是如此。我们对我们的模型进行了彻底的评估,并在几种受试者和不同类型的衣服上展示了不同的动画结果。与以前关于影迷全身化身的工作不同,我们的方法甚至可以为宽松的衣服产生更丰富的动力和更现实的变形。我们还证明,我们的配方自然允许服装与不同人的头像一起使用,同时保持完全动画,因此首次可以采用新颖的衣服来实现逼真的化身。
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基于图像的体积人类使用像素对齐的特征有望泛化,从而看不见姿势和身份。先前的工作利用全局空间编码和多视图几何一致性来减少空间歧义。但是,全球编码通常会过度适应培训数据的分布,并且很难从稀疏视图中学习多视图一致的重建。在这项工作中,我们研究了现有空间编码的常见问题,并提出了一种简单而高效的方法,可以从稀疏视图中对高保真体积的人类进行建模。关键思想之一是通过稀疏3D关键点编码相对空间3D信息。这种方法对观点和跨数据库域间隙的稀疏性很强。我们的方法的表现优于头部重建的最先进方法。关于人体的重建是看不见的受试者,我们还实现了与使用参数人体模型和时间特征聚集的先前工作相当的性能。 Our experiments show that a majority of errors in prior work stem from an inappropriate choice of spatial encoding and thus we suggest a new direction for high-fidelity image-based human modeling. https://markomih.github.io/keypointnerf
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机器学习的最近进步已经创造了利用一类基于坐标的神经网络来解决视觉计算问题的兴趣,该基于坐标的神经网络在空间和时间跨空间和时间的场景或对象的物理属性。我们称之为神经领域的这些方法已经看到在3D形状和图像的合成中成功应用,人体的动画,3D重建和姿势估计。然而,由于在短时间内的快速进展,许多论文存在,但尚未出现全面的审查和制定问题。在本报告中,我们通过提供上下文,数学接地和对神经领域的文学进行广泛综述来解决这一限制。本报告涉及两种维度的研究。在第一部分中,我们通过识别神经字段方法的公共组件,包括不同的表示,架构,前向映射和泛化方法来专注于神经字段的技术。在第二部分中,我们专注于神经领域的应用在视觉计算中的不同问题,超越(例如,机器人,音频)。我们的评论显示了历史上和当前化身的视觉计算中已覆盖的主题的广度,展示了神经字段方法所带来的提高的质量,灵活性和能力。最后,我们展示了一个伴随着贡献本综述的生活版本,可以由社区不断更新。
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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.
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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).
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This study targets the mixed-integer black-box optimization (MI-BBO) problem where continuous and integer variables should be optimized simultaneously. The CMA-ES, our focus in this study, is a population-based stochastic search method that samples solution candidates from a multivariate Gaussian distribution (MGD), which shows excellent performance in continuous BBO. The parameters of MGD, mean and (co)variance, are updated based on the evaluation value of candidate solutions in the CMA-ES. If the CMA-ES is applied to the MI-BBO with straightforward discretization, however, the variance corresponding to the integer variables becomes much smaller than the granularity of the discretization before reaching the optimal solution, which leads to the stagnation of the optimization. In particular, when binary variables are included in the problem, this stagnation more likely occurs because the granularity of the discretization becomes wider, and the existing modification to the CMA-ES does not address this stagnation. To overcome these limitations, we propose a simple extension of the CMA-ES based on lower-bounding the marginal probabilities associated with the generation of integer variables in the MGD. The numerical experiments on the MI-BBO benchmark problems demonstrate the efficiency and robustness of the proposed method. Furthermore, in order to demonstrate the generality of the idea of the proposed method, in addition to the single-objective optimization case, we incorporate it into multi-objective CMA-ES and verify its performance on bi-objective mixed-integer benchmark problems.
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Removing reverb from reverberant music is a necessary technique to clean up audio for downstream music manipulations. Reverberation of music contains two categories, natural reverb, and artificial reverb. Artificial reverb has a wider diversity than natural reverb due to its various parameter setups and reverberation types. However, recent supervised dereverberation methods may fail because they rely on sufficiently diverse and numerous pairs of reverberant observations and retrieved data for training in order to be generalizable to unseen observations during inference. To resolve these problems, we propose an unsupervised method that can remove a general kind of artificial reverb for music without requiring pairs of data for training. The proposed method is based on diffusion models, where it initializes the unknown reverberation operator with a conventional signal processing technique and simultaneously refines the estimate with the help of diffusion models. We show through objective and perceptual evaluations that our method outperforms the current leading vocal dereverberation benchmarks.
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我们提出了一种基于多任务对抗训练的多扬声器神经文本到语音(TTS)模型的新型培训算法。传统的基于基于的训练算法的常规生成对抗网络(GAN)通过减少自然语音和合成语音之间的统计差异来显着提高合成语音的质量。但是,该算法不能保证训练有素的TTS模型的概括性能在综合培训数据中未包括的看不见的说话者的声音中。我们的算法替代训练两个深神经网络:多任务歧视器和多扬声器神经TTS模型(即GAN的生成器)。对歧视者的训练不仅是为了区分自然语音和合成语音,而且还存在验证输入语音的说话者的存在或不存在(即,通过插值可见的说话者的嵌入向量而新生成)。同时,对发电机进行了训练,以最大程度地减少语音重建损失的加权总和和欺骗歧视者的对抗性损失,即使目标扬声器看不见,也可以实现高质量的多演讲者TT。实验评估表明,我们的算法比传统的甘斯多克算法更好地提高了合成语音的质量。
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