Core Viewpoint - A new algorithm, RegGS, developed by the Hong Kong University of Science and Technology (Guangzhou), can reconstruct 3D models from sparse 2D images without precise camera positioning, achieving centimeter-level accuracy suitable for VR applications [2][4]. Group 1: Methodology - RegGS combines feed-forward Gaussian representation with structural registration to address the challenges of sparse and pose-less images, providing a new pathway for practical 3D reconstruction [6][8]. - The core mechanism involves registering local 3D Gaussian mixture models to gradually build a global 3D scene, avoiding reliance on traditional Structure from Motion (SfM) initialization and requiring fewer input images [8][12]. Group 2: Experimental Results - In experiments on the RE10K and ACID datasets, RegGS outperformed existing mainstream methods across various input frame counts (2×/8×/16×/32×) in metrics such as PSNR, SSIM, and LPIPS [9][12]. Group 3: Applications - RegGS addresses the "sparse + pose-less" problem with significant real-world applications, including: - 3D reconstruction from user-generated content (UGC) videos, which often lack camera parameters [13]. - Drone aerial mapping, demonstrating robustness to large viewpoint variations and low frame rates [13]. - Restoration of historical images/documents, enabling 3D reconstruction from a few photos taken from different angles [13]. - Compared to traditional SfM or Bundle Adjustment methods, RegGS requires less structural input and is more feasible for unstructured data applications [13]. Group 4: Limitations and Future Directions - The performance and efficiency of RegGS are currently limited by the quality of the upstream feed-forward model and the computational cost of the MW2 distance calculation, indicating areas for future optimization [13].