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HuGDiffusion: Generalizable Single-Image Human Rendering via 3D Gaussian Diffusion

Yingzhi Tang, Qijian Zhang, Junhui Hou

TL;DR

HuGDiffusion tackles single-image novel-view synthesis of humans by learning a generalizable 3D Gaussian splatting (3DGS) representation through diffusion, conditioned on human priors extracted from the input image. It introduces a two-stage proxy ground-truth construction to produce attribute-level supervision and uses a position generator plus a conditional diffuser to predict Gaussian positions and attributes, respectively, with pixel-aligned and SMPL-semantic conditioning. The approach achieves state-of-the-art quantitative and perceptual results across multiple datasets and demonstrates strong generalization to in-the-wild images, while offering insights into the benefits of diffusion over regression for occluded regions. With its fast, view-consistent rendering and open-sourced implementation plan, HuGDiffusion has practical potential for real-time humanoid rendering in games, film, and AR/VR pipelines.

Abstract

We present HuGDiffusion, a generalizable 3D Gaussian splatting (3DGS) learning pipeline to achieve novel view synthesis (NVS) of human characters from single-view input images. Existing approaches typically require monocular videos or calibrated multi-view images as inputs, whose applicability could be weakened in real-world scenarios with arbitrary and/or unknown camera poses. In this paper, we aim to generate the set of 3DGS attributes via a diffusion-based framework conditioned on human priors extracted from a single image. Specifically, we begin with carefully integrated human-centric feature extraction procedures to deduce informative conditioning signals. Based on our empirical observations that jointly learning the whole 3DGS attributes is challenging to optimize, we design a multi-stage generation strategy to obtain different types of 3DGS attributes. To facilitate the training process, we investigate constructing proxy ground-truth 3D Gaussian attributes as high-quality attribute-level supervision signals. Through extensive experiments, our HuGDiffusion shows significant performance improvements over the state-of-the-art methods. Our code will be made publicly available.

HuGDiffusion: Generalizable Single-Image Human Rendering via 3D Gaussian Diffusion

TL;DR

HuGDiffusion tackles single-image novel-view synthesis of humans by learning a generalizable 3D Gaussian splatting (3DGS) representation through diffusion, conditioned on human priors extracted from the input image. It introduces a two-stage proxy ground-truth construction to produce attribute-level supervision and uses a position generator plus a conditional diffuser to predict Gaussian positions and attributes, respectively, with pixel-aligned and SMPL-semantic conditioning. The approach achieves state-of-the-art quantitative and perceptual results across multiple datasets and demonstrates strong generalization to in-the-wild images, while offering insights into the benefits of diffusion over regression for occluded regions. With its fast, view-consistent rendering and open-sourced implementation plan, HuGDiffusion has practical potential for real-time humanoid rendering in games, film, and AR/VR pipelines.

Abstract

We present HuGDiffusion, a generalizable 3D Gaussian splatting (3DGS) learning pipeline to achieve novel view synthesis (NVS) of human characters from single-view input images. Existing approaches typically require monocular videos or calibrated multi-view images as inputs, whose applicability could be weakened in real-world scenarios with arbitrary and/or unknown camera poses. In this paper, we aim to generate the set of 3DGS attributes via a diffusion-based framework conditioned on human priors extracted from a single image. Specifically, we begin with carefully integrated human-centric feature extraction procedures to deduce informative conditioning signals. Based on our empirical observations that jointly learning the whole 3DGS attributes is challenging to optimize, we design a multi-stage generation strategy to obtain different types of 3DGS attributes. To facilitate the training process, we investigate constructing proxy ground-truth 3D Gaussian attributes as high-quality attribute-level supervision signals. Through extensive experiments, our HuGDiffusion shows significant performance improvements over the state-of-the-art methods. Our code will be made publicly available.
Paper Structure (31 sections, 12 equations, 24 figures, 8 tables)

This paper contains 31 sections, 12 equations, 24 figures, 8 tables.

Figures (24)

  • Figure 1: (a) The traditional paradigm uses a splat-based rasterizer to supervise training with image signals. (b) HugDiffusion trains a diffusion model with 3D Gaussian attributes as supervision signals.
  • Figure 2: The two-stage workflow of creating proxy ground-truth Gaussian attributes.
  • Figure 3: The framework of our HuGDiffusion. HuGDiffusion predicts 3D Gaussian positions and a back-view image using a position generator and a stable diffusion module. It assigns SMPL semantic labels to points in 3D Gaussians, deducing an SMPL-semantic feature. The 3D Gaussians are decomposed for front- and back-view projection, achieving a pixel-aligned feature. Both features condition the 3D Gaussian attribute diffuser.
  • Figure 4: (a) The large variation of vanilla-3DGS spherical harmonic values after 200 attempts on a scene. (b) Spherical harmonic values comparison of the local area (marked with yellow) between vanilla-3DGS and our proxy ground-truth 3D Gaussian attributes. (c) Visualization of spherical harmonic, opacity, and scale for vanilla-3DGS and our proxy ground-truth 3D Gaussian attributes. Zoom in for details.
  • Figure 5: The visualization of distributions and loss. Zoom in for details.
  • ...and 19 more figures