Identity-Aware Language Gaussian Splatting for Open-Vocabulary 3D Semantic Segmentation

Open-vocabulary 3D semantic segmentation has been actively studied by incorporating language features into 3D scene representations. Even though many methods have shown the notable improvement in this task, they still have difficulties to make language embeddings be consistent across different views. This inconsistency highly results in mis-labeling where different language embeddings are assigned to the same part of an object. To address this issue, we propose a simple yet powerful method that aligns language embeddings via the identity information. The key idea is to locate language embeddings for the same identity closely in the latent space while putting them apart otherwise. This approach allows the same object to have identical language embeddings in novel views with accurate semantic masks, which are well aligned with the input text. Furthermore, we propose a progressive mask expanding scheme that enables more accurate extraction of semantic mask boundaries. This scheme is very effective in preserving the boundary shape of the target region by allowing the model to consider the local relationship between segments. Experimental results on benchmark datasets demonstrate that our method delivers state-of-the-art performance in open-vocabulary 3D semantic segmentation.