我们提出了一种使用高质量的OCTREE发射的代表来渲染复杂灯具的有效方法。复杂的灯具在渲染中是一个特别具有挑战性的问题,因为它们的腐蚀性光路在灯具内部。我们通过使用简单的代理几何形状来降低照明器的几何复杂性,并使用神经辐射场编码视觉复杂的发射光场。我们通过提出专门的损失函数来应对代表灯具的多重挑战,包括其高动态范围,高频含量和空发射区域。为了进行渲染,我们将灯具的nerf提炼成圆锥状的,我们可以轻松地将其集成到传统的渲染系统中。我们的方法允许在包含最小误差的复杂灯具的场景中加速2个数量级。
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Physically based rendering of complex scenes can be prohibitively costly with a potentially unbounded and uneven distribution of complexity across the rendered image. The goal of an ideal level of detail (LoD) method is to make rendering costs independent of the 3D scene complexity, while preserving the appearance of the scene. However, current prefiltering LoD methods are limited in the appearances they can support due to their reliance of approximate models and other heuristics. We propose the first comprehensive multi-scale LoD framework for prefiltering 3D environments with complex geometry and materials (e.g., the Disney BRDF), while maintaining the appearance with respect to the ray-traced reference. Using a multi-scale hierarchy of the scene, we perform a data-driven prefiltering step to obtain an appearance phase function and directional coverage mask at each scale. At the heart of our approach is a novel neural representation that encodes this information into a compact latent form that is easy to decode inside a physically based renderer. Once a scene is baked out, our method requires no original geometry, materials, or textures at render time. We demonstrate that our approach compares favorably to state-of-the-art prefiltering methods and achieves considerable savings in memory for complex scenes.
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重建反向渲染技术的最新趋势使用神经网络将3D表示作为神经领域。基于NERF的技术将多层感知器(MLP)拟合到一组训练图像,以估算一个辐射场字段,然后可以通过卷渲染算法从任何虚拟摄像机呈现。这些表示形式的主要缺点是缺乏定义明确的表面和非交互式渲染时间,因为必须查询宽大和深的MLP,每个框架必须查询数百万次。这些限制最近被单一克服了,但是设法同时完成了这一限制,从而打开了新的用例。我们提出了Kiloneus,这是一种新的神经对象表示,可以在交互式框架速率下的路径跟踪场景中渲染。 Kiloneus可以在共享场景中对神经和经典原语之间的逼真的光相互作用进行模拟,并且它可以实时执行,并有足够的空间进行未来的优化和扩展。
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We present a method that takes as input a set of images of a scene illuminated by unconstrained known lighting, and produces as output a 3D representation that can be rendered from novel viewpoints under arbitrary lighting conditions. Our method represents the scene as a continuous volumetric function parameterized as MLPs whose inputs are a 3D location and whose outputs are the following scene properties at that input location: volume density, surface normal, material parameters, distance to the first surface intersection in any direction, and visibility of the external environment in any direction. Together, these allow us to render novel views of the object under arbitrary lighting, including indirect illumination effects. The predicted visibility and surface intersection fields are critical to our model's ability to simulate direct and indirect illumination during training, because the brute-force techniques used by prior work are intractable for lighting conditions outside of controlled setups with a single light. Our method outperforms alternative approaches for recovering relightable 3D scene representations, and performs well in complex lighting settings that have posed a significant challenge to prior work.
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我们介绍了Plenoxels(plenoptic voxels),是一种光电型观测合成系统。Plenoxels表示作为具有球形谐波的稀疏3D网格的场景。该表示可以通过梯度方法和正则化从校准图像进行优化,而没有任何神经元件。在标准,基准任务中,Plenoxels优化了比神经辐射场更快的两个数量级,无需视觉质量损失。
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最近的神经渲染方法通过用神经网络预测体积密度和颜色来证明了准确的视图插值。虽然可以在静态和动态场景上监督这种体积表示,但是现有方法隐含地将完整的场景光传输释放到一个神经网络中,用于给定场景,包括曲面建模,双向散射分布函数和间接照明效果。与传统的渲染管道相比,这禁止在场景中改变表面反射率,照明或构成其他物体。在这项工作中,我们明确地模拟了场景表面之间的光传输,我们依靠传统的集成方案和渲染方程来重建场景。所提出的方法允许BSDF恢复,具有未知的光条件和诸如路径传输的经典光传输。通过在传统渲染方法中建立的表面表示的分解传输,该方法自然促进了编辑形状,反射率,照明和场景组成。该方法优于神经,在已知的照明条件下可发光,并为refit和编辑场景产生现实的重建。我们验证了从综合和捕获的视图上了解的场景编辑,致密和反射率估算的建议方法,并捕获了神经数据集的子集。
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We introduce a method to render Neural Radiance Fields (NeRFs) in real time using PlenOctrees, an octree-based 3D representation which supports view-dependent effects. Our method can render 800×800 images at more than 150 FPS, which is over 3000 times faster than conventional NeRFs. We do so without sacrificing quality while preserving the ability of NeRFs to perform free-viewpoint rendering of scenes with arbitrary geometry and view-dependent effects. Real-time performance is achieved by pre-tabulating the NeRF into a PlenOctree. In order to preserve viewdependent effects such as specularities, we factorize the appearance via closed-form spherical basis functions. Specifically, we show that it is possible to train NeRFs to predict a spherical harmonic representation of radiance, removing the viewing direction as an input to the neural network. Furthermore, we show that PlenOctrees can be directly optimized to further minimize the reconstruction loss, which leads to equal or better quality compared to competing methods. Moreover, this octree optimization step can be used to reduce the training time, as we no longer need to wait for the NeRF training to converge fully. Our real-time neural rendering approach may potentially enable new applications such as 6-DOF industrial and product visualizations, as well as next generation AR/VR systems. PlenOctrees are amenable to in-browser rendering as well; please visit the project page for the interactive online demo, as well as video and code: https://alexyu. net/plenoctrees.
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综合照片 - 现实图像和视频是计算机图形的核心,并且是几十年的研究焦点。传统上,使用渲染算法(如光栅化或射线跟踪)生成场景的合成图像,其将几何形状和材料属性的表示为输入。统称,这些输入定义了实际场景和呈现的内容,并且被称为场景表示(其中场景由一个或多个对象组成)。示例场景表示是具有附带纹理的三角形网格(例如,由艺术家创建),点云(例如,来自深度传感器),体积网格(例如,来自CT扫描)或隐式曲面函数(例如,截短的符号距离)字段)。使用可分辨率渲染损耗的观察结果的这种场景表示的重建被称为逆图形或反向渲染。神经渲染密切相关,并将思想与经典计算机图形和机器学习中的思想相结合,以创建用于合成来自真实观察图像的图像的算法。神经渲染是朝向合成照片现实图像和视频内容的目标的跨越。近年来,我们通过数百个出版物显示了这一领域的巨大进展,这些出版物显示了将被动组件注入渲染管道的不同方式。这种最先进的神经渲染进步的报告侧重于将经典渲染原则与学习的3D场景表示结合的方法,通常现在被称为神经场景表示。这些方法的一个关键优势在于它们是通过设计的3D-一致,使诸如新颖的视点合成捕获场景的应用。除了处理静态场景的方法外,我们还涵盖了用于建模非刚性变形对象的神经场景表示...
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Photo-realistic free-viewpoint rendering of real-world scenes using classical computer graphics techniques is challenging, because it requires the difficult step of capturing detailed appearance and geometry models. Recent studies have demonstrated promising results by learning scene representations that implicitly encode both geometry and appearance without 3D supervision. However, existing approaches in practice often show blurry renderings caused by the limited network capacity or the difficulty in finding accurate intersections of camera rays with the scene geometry. Synthesizing high-resolution imagery from these representations often requires time-consuming optical ray marching. In this work, we introduce Neural Sparse Voxel Fields (NSVF), a new neural scene representation for fast and high-quality free-viewpoint rendering. NSVF defines a set of voxel-bounded implicit fields organized in a sparse voxel octree to model local properties in each cell. We progressively learn the underlying voxel structures with a diffentiable ray-marching operation from only a set of posed RGB images. With the sparse voxel octree structure, rendering novel views can be accelerated by skipping the voxels containing no relevant scene content. Our method is typically over 10 times faster than the state-of-the-art (namely, NeRF (Mildenhall et al., 2020)) at inference time while achieving higher quality results. Furthermore, by utilizing an explicit sparse voxel representation, our method can easily be applied to scene editing and scene composition. We also demonstrate several challenging tasks, including multi-scene learning, free-viewpoint rendering of a moving human, and large-scale scene rendering. Code and data are available at our website: https://github.com/facebookresearch/NSVF.
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Google Research Basecolor Metallic Roughness Normal Multi-View Images NeRD Volume Decomposed BRDF Relighting & View synthesis Textured MeshFigure 1: Neural Reflectance Decomposition for Relighting. We encode multiple views of an object under varying or fixed illumination into the NeRD volume.We decompose each given image into geometry, spatially-varying BRDF parameters and a rough approximation of the incident illumination in a globally consistent manner. We then extract a relightable textured mesh that can be re-rendered under novel illumination conditions in real-time.
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We present a method that achieves state-of-the-art results for synthesizing novel views of complex scenes by optimizing an underlying continuous volumetric scene function using a sparse set of input views. Our algorithm represents a scene using a fully-connected (nonconvolutional) deep network, whose input is a single continuous 5D coordinate (spatial location (x, y, z) and viewing direction (θ, φ)) and whose output is the volume density and view-dependent emitted radiance at that spatial location. We synthesize views by querying 5D coordinates along camera rays and use classic volume rendering techniques to project the output colors and densities into an image. Because volume rendering is naturally differentiable, the only input required to optimize our representation is a set of images with known camera poses. We describe how to effectively optimize neural radiance fields to render photorealistic novel views of scenes with complicated geometry and appearance, and demonstrate results that outperform prior work on neural rendering and view synthesis. View synthesis results are best viewed as videos, so we urge readers to view our supplementary video for convincing comparisons.
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潜水员在NERF的关键思想和其变体 - 密度模型和体积渲染的关键思想中建立 - 学习可以从少量图像实际渲染的3D对象模型。与所有先前的NERF方法相比,潜水员使用确定性而不是体积渲染积分的随机估计。潜水员的表示是基于体素的功能领域。为了计算卷渲染积分,将光线分为间隔,每个体素;使用MLP的每个间隔的特征估计体渲染积分的组件,并且组件聚合。结果,潜水员可以呈现其他集成商错过的薄半透明结构。此外,潜水员的表示与其他这样的方法相比相对暴露的语义 - 在体素空间中的运动特征向量导致自然编辑。对当前最先进的方法的广泛定性和定量比较表明,潜水员产生(1)在最先进的质量或高于最先进的质量,(2)的情况下非常小而不会被烘烤,(3)在不被烘烤的情况下渲染非常快,并且(4)可以以自然方式编辑。
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NeRF synthesizes novel views of a scene with unprecedented quality by fitting a neural radiance field to RGB images. However, NeRF requires querying a deep Multi-Layer Perceptron (MLP) millions of times, leading to slow rendering times, even on modern GPUs. In this paper, we demonstrate that real-time rendering is possible by utilizing thousands of tiny MLPs instead of one single large MLP. In our setting, each individual MLP only needs to represent parts of the scene, thus smaller and faster-to-evaluate MLPs can be used. By combining this divide-and-conquer strategy with further optimizations, rendering is accelerated by three orders of magnitude compared to the original NeRF model without incurring high storage costs. Further, using teacher-student distillation for training, we show that this speed-up can be achieved without sacrificing visual quality.
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神经辐射场(NERFS)产生最先进的视图合成结果。然而,它们慢渲染,需要每像素数百个网络评估,以近似卷渲染积分。将nerfs烘烤到明确的数据结构中实现了有效的渲染,但导致内存占地面积的大幅增加,并且在许多情况下,质量降低。在本文中,我们提出了一种新的神经光场表示,相反,相反,紧凑,直接预测沿线的集成光线。我们的方法支持使用每个像素的单个网络评估,用于小基线光场数据集,也可以应用于每个像素的几个评估的较大基线。在我们的方法的核心,是一个光线空间嵌入网络,将4D射线空间歧管映射到中间可间可动子的潜在空间中。我们的方法在诸如斯坦福光场数据集等密集的前置数据集中实现了最先进的质量。此外,对于带有稀疏输入的面对面的场景,我们可以在质量方面实现对基于NERF的方法具有竞争力的结果,同时提供更好的速度/质量/内存权衡,网络评估较少。
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我们建议使用以光源方向为条件的神经辐射场(NERF)的扩展来解决多视光度立体声问题。我们神经表示的几何部分预测表面正常方向,使我们能够理解局部表面反射率。我们的神经表示的外观部分被分解为神经双向反射率函数(BRDF),作为拟合过程的一部分学习,阴影预测网络(以光源方向为条件),使我们能够对明显的BRDF进行建模。基于物理图像形成模型的诱导偏差的学到的组件平衡使我们能够远离训练期间观察到的光源和查看器方向。我们证明了我们在多视光学立体基准基准上的方法,并表明可以通过NERF的神经密度表示可以获得竞争性能。
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我们提出了一种可区分的渲染算法,以进行有效的新型视图合成。通过偏离基于音量的表示,支持学习点表示,我们在训练和推理方面的内存和运行时范围内改进了现有方法的数量级。该方法从均匀采样的随机点云开始,并使用基于可区分的SPLAT渲染器来发展模型以匹配一组输入图像,从而学习了每点位置和观看依赖性外观。在训练和推理中,我们的方法比NERF快300倍,质量只有边缘牺牲,而在静态场景中使用少于10 〜MB的记忆。对于动态场景,我们的方法比Stnerf训练两个数量级,并以接近互动速率渲染,同时即使在不施加任何时间固定的正则化合物的情况下保持较高的图像质量和时间连贯性。
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神经辐射场(NERF)是一种普遍的视图综合技术,其表示作为连续体积函数的场景,由多层的感知来参数化,其提供每个位置处的体积密度和视图相关的发射辐射。虽然基于NERF的技术在代表精细的几何结构时,具有平稳变化的视图依赖性外观,但它们通常无法精确地捕获和再现光泽表面的外观。我们通过引入Ref-nerf来解决这些限制,该ref-nerf替换了nerf的视图依赖性输出辐射的参数化,使用反射辐射的表示和使用空间不同场景属性的集合来构造该函数的表示。我们展示了与正常载体上的规范器一起,我们的模型显着提高了镜面反射的现实主义和准确性。此外,我们表明我们的模型的外向光线的内部表示是可解释的,可用于场景编辑。
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在本文中,我们为复杂场景进行了高效且强大的深度学习解决方案。在我们的方法中,3D场景表示为光场,即,一组光线,每组在到达图像平面时具有相应的颜色。对于高效的新颖视图渲染,我们采用了光场的双面参数化,其中每个光线的特征在于4D参数。然后,我们将光场配向作为4D函数,即将4D坐标映射到相应的颜色值。我们训练一个深度完全连接的网络以优化这种隐式功能并记住3D场景。然后,特定于场景的模型用于综合新颖视图。与以前需要密集的视野的方法不同,需要密集的视野采样来可靠地呈现新颖的视图,我们的方法可以通过采样光线来呈现新颖的视图并直接从网络查询每种光线的颜色,从而使高质量的灯场呈现稀疏集合训练图像。网络可以可选地预测每光深度,从而使诸如自动重新焦点的应用。我们的小说视图合成结果与最先进的综合结果相当,甚至在一些具有折射和反射的具有挑战性的场景中优越。我们在保持交互式帧速率和小的内存占地面积的同时实现这一点。
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可区分渲染的最新进展已实现了从多视图图像中对3D场景的高质量重建。大多数方法都依赖于简单渲染算法:预滤波的直接照明或学习的辐照度表示。我们表明,更现实的阴影模型,结合了射线追踪和蒙特卡洛整合,大大改善了形状,材料和照明的分解。不幸的是,即使在大型样本计数下,蒙特卡洛集成也能提供巨大的噪音,这使得基于梯度的逆渲染非常具有挑战性。为了解决这个问题,我们将多重重要性采样和降解纳入新的逆渲染管道中。这显着改善了收敛性,并在低样本计数下实现了基于梯度的优化。我们提出了一种有效的方法,可以共同重建几何形状(显式三角形网格),材料和照明,与以前的工作相比,它显着改善了材料和光分离。我们认为,Denoising可以成为高质量逆渲染管道的组成部分。
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Creating realistic virtual assets is a time-consuming process: it usually involves an artist designing the object, then spending a lot of effort on tweaking its appearance. Intricate details and certain effects, such as subsurface scattering, elude representation using real-time BRDFs, making it impossible to fully capture the appearance of certain objects. Inspired by the recent progress of neural rendering, we propose an approach for capturing real-world objects in everyday environments faithfully and fast. We use a novel neural representation to reconstruct volumetric effects, such as translucent object parts, and preserve photorealistic object appearance. To support real-time rendering without compromising rendering quality, our model uses a grid of features and a small MLP decoder that is transpiled into efficient shader code with interactive framerates. This leads to a seamless integration of the proposed neural assets with existing mesh environments and objects. Thanks to the use of standard shader code rendering is portable across many existing hardware and software systems.
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