Eduard Gabriel Bazavan
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SPHEAR: Spherical Head Registration for Complete Statistical 3D Modeling
Andrei Zanfir
Teodor Szente
Mihai Zanfir
International Conference on 3D Vision (2024)
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We present SPHEAR, an accurate, differentiable parametric statistical 3D human head model, enabled by a novel 3D registration method based on spherical embeddings. We shift the paradigm away from the classical Non-Rigid Registration methods, which operate under various surface priors, increasing reconstruction fidelity and minimizing required human intervention. Additionally, SPHEAR is a complete model that allows not only to sample diverse synthetic head shapes and facial expressions, but also gaze directions, high-resolution color textures, surface normal maps, and hair cuts represented in detail, as strands. SPHEAR can be used for automatic realistic visual data generation, semantic annotation, and general reconstruction tasks. Compared to state-of-the-art approaches, our components are fast and memory efficient, and experiments support the validity of our design choices and the accuracy of registration, reconstruction and generation techniques.
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Instant 3D Human Avatar Generation using Image Diffusion Models
Enric Corona
European Conference on Computer Vision (ECCV) (2024)
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We present AvatarPopUp, a method for fast, high quality 3D human avatar generation from different input modalities, such as images and text prompts and with control over the generated pose and shape. The common theme is the use of diffusion-based image generation networks that are specialized for each particular task, followed by a 3D lifting network. We purposefully decouple the generation from the 3D modeling which allow us to leverage powerful image synthesis priors, trained on billions of text-image pairs. We fine-tune latent diffusion networks with additional image conditioning for image generation and back-view prediction, and to support qualitatively different multiple 3D hypotheses. Our partial fine-tuning approach allows to adapt the networks for each task without inducing catastrophic forgetting. In our experiments, we demonstrate that our method produces accurate, high-quality 3D avatars with diverse appearance that respect the multimodal text, image, and body control signals. Our approach can produce a 3D model in as few as 2 seconds, a four orders of magnitude speedup w.r.t. the vast majority of existing methods, most of which solve only a subset of our tasks, and with fewer controls. AvatarPopUp enables applications that require the controlled 3D generation of human avatars at scale.
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DreamHuman: Animatable 3D Avatars from Text
Andrei Zanfir
Mihai Fieraru
Advances in Neural Information Processing Systems (2023)
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We present DreamHuman, a method to generate realistic animatable 3D human avatar models solely from textual descriptions. Recent text-to-3D methods have made considerable strides in generation, but are still lacking in important aspects. Control and often spatial resolution remain limited, existing methods produce fixed rather than animated 3D human models, and anthropometric consistency for complex structures like people remains a challenge. DreamHuman connects large text-to-image synthesis models, neural radiance fields, and statistical human body models in a novel modeling and optimization framework. This makes it possible to generate dynamic 3D human avatars with high-quality textures and learned, instance-specific, surface deformations. We demonstrate that our method is capable to generate a wide variety of animatable, realistic 3D human models from text. Our 3D models have diverse appearance, clothing, skin tones and body shapes, and significantly outperform both generic text-to-3D approaches and previous text-based 3D avatar generators in visual fidelity.
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Structured 3D Features for Reconstructing Controllable Avatars
Enric Corona
Mihai Zanfir
Andrei Zanfir
Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) (2023)
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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 & 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.
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Neural Descent for Visual 3D Human Pose and Shape
Andrei Zanfir
Mihai Zanfir
Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) (2021), pp. 14484-14493
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We present a deep neural network methodology to reconstruct the 3d pose and shape of people, given image or video inputs. We rely on a recently introduced, expressive full body statistical 3d human model, GHUM, with facial expression and hand detail and aim to learn to reconstruct the model pose and shape states in a self-supervised regime. Central to our methodology, is a learning to learn approach, referred to as HUman Neural Descent (HUND) that avoids both second-order differentiation when training the model parameters, and expensive state gradient descent in order to accurately minimize a semantic differentiable rendering loss at test time. Instead, we rely on novel recurrent stages to update the pose and shape parameters such that not only losses are minimized effectively but the process is regularized in order to ensure progress.
The newly introduced architecture is tested extensively, and achieves state-of-the-art results on datasets like H3.6M and 3DPW, as well as in complex imagery collected in-the-wild.
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THUNDR: Transformer-based 3D HUmaN Reconstruction with Markers
Mihai Zanfir
Andrei Zanfir
Proceedings of the IEEE/CVF International Conference on Computer Vision (2021)
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We present THUNDR, a transformer-based deep neural network methodology to reconstruct the 3D pose and shape of people, given monocular RGB images. Key to our methodology is an intermediate 3D marker representation, where we aim to combine the predictive power of model-free output architectures and the regularizing, anthropometrically-preserving properties of a statistical human surface models like GHUM—a recently introduced, expressive full body statistical 3d human model, trained end-to-end. Our novel transformer-based prediction pipeline can focus on image regions relevant to the task, supports self-supervised regimes, and ensures that solutions are consistent with human anthropometry. We show state-of-the-art results on Human3.6M and 3DPW, for both the fully-supervised and the self-supervised models, for the task of inferring 3D human shape, joint positions, and global translation. Moreover, we observe very solid 3d reconstruction performance for difficult human poses collected in the wild. Models will be made available for research.
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Weakly Supervised 3D Human Pose and Shape Reconstruction with Normalizing Flows
Andrei Zanfir
Hongyi Xu
European Conference on Computer Vision (ECCV) (2020), pp. 465-481
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Monocular 3D human pose and shape estimation is challenging due to the many degrees of freedom of the human body and thedifficulty to acquire training data for large-scale supervised learning incomplex visual scenes. In this paper we present practical semi-supervisedand self-supervised models that support training and good generalizationin real-world images and video. Our formulation is based on kinematiclatent normalizing flow representations and dynamics, as well as differ-entiable, semantic body part alignment loss functions that support self-supervised learning. In extensive experiments using 3D motion capturedatasets like CMU, Human3.6M, 3DPW, or AMASS, as well as imagerepositories like COCO, we show that the proposed methods outperformthe state of the art, supporting the practical construction of an accuratefamily of models based on large-scale training with diverse and incom-pletely labeled image and video data.
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GHUM & GHUML: Generative 3D Human Shape and Articulated Pose Models
Hongyi Xu
Andrei Zanfir
IEEE/CVF Conference on Computer Vision and Pattern Recognition (Oral) (2020), pp. 6184-6193
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We present a statistical, articulated 3D human shape modeling pipeline, within a fully trainable, modular, deep learning framework. Given high-resolution complete 3D body scans of humans, captured in various poses, together with additional closeups of their head and facial expressions, as well as hand articulation, and given initial, artist designed, gender neutral rigged quad-meshes, we train all model parameters including non-linear shape spaces based on variational auto-encoders, pose-space deformation correctives, skeleton joint center predictors, and blend skinning functions, in a single consistent learning loop. The models are simultaneously trained with all the 3d dynamic scan data (over60,000diverse human configurations in our new dataset) in order to capture correlations and en-sure consistency of various components. Models support facial expression analysis, as well as body (with detailed hand) shape and pose estimation. We provide fully train-able generic human models of different resolutions – the moderate-resolution GHUM consisting of 10,168 vertices and the low-resolution GHUML(ite) of 3,194 vertices –, run comparisons between them, analyze the impact of different components and illustrate their reconstruction from image data. The models are available for research.
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