261 research outputs found
Recovering refined surface normals for relighting clothing in dynamic scenes
In this paper we present a method to relight captured 3D video sequences of non-rigid, dynamic scenes, such as clothing of real actors, reconstructed from multiple view video. A view-dependent approach is introduced to refine an initial coarse surface reconstruction using shape-from-shading to estimate detailed surface normals. The prior surface approximation is used to constrain the simultaneous estimation of surface normals and scene illumination, under the assumption of Lambertian surface reflectance. This approach enables detailed surface normals of a moving non-rigid object to be estimated from a single image frame. Refined normal estimates from multiple views are integrated into a single surface normal map. This approach allows highly non-rigid surfaces, such as creases in clothing, to be relit whilst preserving the detailed dynamics observed in video
NARRATE: A Normal Assisted Free-View Portrait Stylizer
In this work, we propose NARRATE, a novel pipeline that enables
simultaneously editing portrait lighting and perspective in a photorealistic
manner. As a hybrid neural-physical face model, NARRATE leverages complementary
benefits of geometry-aware generative approaches and normal-assisted physical
face models. In a nutshell, NARRATE first inverts the input portrait to a
coarse geometry and employs neural rendering to generate images resembling the
input, as well as producing convincing pose changes. However, inversion step
introduces mismatch, bringing low-quality images with less facial details. As
such, we further estimate portrait normal to enhance the coarse geometry,
creating a high-fidelity physical face model. In particular, we fuse the neural
and physical renderings to compensate for the imperfect inversion, resulting in
both realistic and view-consistent novel perspective images. In relighting
stage, previous works focus on single view portrait relighting but ignoring
consistency between different perspectives as well, leading unstable and
inconsistent lighting effects for view changes. We extend Total Relighting to
fix this problem by unifying its multi-view input normal maps with the physical
face model. NARRATE conducts relighting with consistent normal maps, imposing
cross-view constraints and exhibiting stable and coherent illumination effects.
We experimentally demonstrate that NARRATE achieves more photorealistic,
reliable results over prior works. We further bridge NARRATE with animation and
style transfer tools, supporting pose change, light change, facial animation,
and style transfer, either separately or in combination, all at a photographic
quality. We showcase vivid free-view facial animations as well as 3D-aware
relightable stylization, which help facilitate various AR/VR applications like
virtual cinematography, 3D video conferencing, and post-production.Comment: 14 pages,13 figures https://youtu.be/mP4FV3evmy
Self-supervised Outdoor Scene Relighting
Outdoor scene relighting is a challenging problem that requires good
understanding of the scene geometry, illumination and albedo. Current
techniques are completely supervised, requiring high quality synthetic
renderings to train a solution. Such renderings are synthesized using priors
learned from limited data. In contrast, we propose a self-supervised approach
for relighting. Our approach is trained only on corpora of images collected
from the internet without any user-supervision. This virtually endless source
of training data allows training a general relighting solution. Our approach
first decomposes an image into its albedo, geometry and illumination. A novel
relighting is then produced by modifying the illumination parameters. Our
solution capture shadow using a dedicated shadow prediction map, and does not
rely on accurate geometry estimation. We evaluate our technique subjectively
and objectively using a new dataset with ground-truth relighting. Results show
the ability of our technique to produce photo-realistic and physically
plausible results, that generalizes to unseen scenes.Comment: Published in ECCV '20,
http://gvv.mpi-inf.mpg.de/projects/SelfRelight
State of the Art on Neural Rendering
Efficient rendering of photo-realistic virtual worlds is a long standing effort of computer graphics. Modern graphics techniques have succeeded in synthesizing photo-realistic images from hand-crafted scene representations. However, the automatic generation of shape, materials, lighting, and other aspects of scenes remains a challenging problem that, if solved, would make photo-realistic computer graphics more widely accessible. Concurrently, progress in computer vision and machine learning have given rise to a new approach to image synthesis and editing, namely deep generative models. Neural rendering is a new and rapidly emerging field that combines generative machine learning techniques with physical knowledge from computer graphics, e.g., by the integration of differentiable rendering into network training. With a plethora of applications in computer graphics and vision, neural rendering is poised to become a new area in the graphics community, yet no survey of this emerging field exists. This state-of-the-art report summarizes the recent trends and applications of neural rendering. We focus on approaches that combine classic computer graphics techniques with deep generative models to obtain controllable and photo-realistic outputs. Starting with an overview of the underlying computer graphics and machine learning concepts, we discuss critical aspects of neural rendering approaches. This state-of-the-art report is focused on the many important use cases for the described algorithms such as novel view synthesis, semantic photo manipulation, facial and body reenactment, relighting, free-viewpoint video, and the creation of photo-realistic avatars for virtual and augmented reality telepresence. Finally, we conclude with a discussion of the social implications of such technology and investigate open research problems
Relighting4D: Neural Relightable Human from Videos
Human relighting is a highly desirable yet challenging task. Existing works
either require expensive one-light-at-a-time (OLAT) captured data using light
stage or cannot freely change the viewpoints of the rendered body. In this
work, we propose a principled framework, Relighting4D, that enables
free-viewpoints relighting from only human videos under unknown illuminations.
Our key insight is that the space-time varying geometry and reflectance of the
human body can be decomposed as a set of neural fields of normal, occlusion,
diffuse, and specular maps. These neural fields are further integrated into
reflectance-aware physically based rendering, where each vertex in the neural
field absorbs and reflects the light from the environment. The whole framework
can be learned from videos in a self-supervised manner, with physically
informed priors designed for regularization. Extensive experiments on both real
and synthetic datasets demonstrate that our framework is capable of relighting
dynamic human actors with free-viewpoints.Comment: ECCV 2022; Project Page
https://frozenburning.github.io/projects/relighting4d Codes are available at
https://github.com/FrozenBurning/Relighting4
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