SpaRP: Fast 3D Object Reconstruction and Pose Estimation from Sparse
  Views
Authors: name: Chao Xu, name: Ang Li, name: Linghao Chen, name: Yulin Liu, name: Ruoxi Shi, name: Hao Su, name: Minghua Liu

Open-world 3D generation has recently attracted considerable attention. While
many single-image-to-3D methods have yielded visually appealing outcomes, they
often lack sufficient controllability and tend to produce hallucinated regions
that may not align with users' expectations. In this paper, we explore an
important scenario in which the input consists of one or a few unposed 2D
images of a single object, with little or no overlap. We propose a novel
method, SpaRP, to reconstruct a 3D textured mesh and estimate the relative
camera poses for these sparse-view images. SpaRP distills knowledge from 2D
diffusion models and finetunes them to implicitly deduce the 3D spatial
relationships between the sparse views. The diffusion model is trained to
jointly predict surrogate representations for camera poses and multi-view
images of the object under known poses, integrating all information from the
input sparse views. These predictions are then leveraged to accomplish 3D
reconstruction and pose estimation, and the reconstructed 3D model can be used
to further refine the camera poses of input views. Through extensive
experiments on three datasets, we demonstrate that our method not only
significantly outperforms baseline methods in terms of 3D reconstruction
quality and pose prediction accuracy but also exhibits strong efficiency. It
requires only about 20 seconds to produce a textured mesh and camera poses for
the input views. Project page: https://chaoxu.xyz/sparp.