OpenScan: A Benchmark for Generalized Open-Vocabulary 3D Scene Understanding
Youjun Zhao, Jiaying Lin, Shuquan Ye, Qianshi Pang, Rynson W. H. Lau
TL;DR
This work defines Generalized Open-Vocabulary 3D Scene Understanding (GOV-3D) to extend OV-3D beyond object-class queries to abstract object attributes. It introduces OpenScan, a large-scale benchmark based on ScanNet200 that annotates 341 attributes across eight linguistic aspects (affordance, property, type, manner, synonym, requirement, element, material) over 1,513 scenes, enabling comprehensive evaluation of attribute-grounded 3D understanding. Across seven strong OV-3D baselines, results reveal substantial gaps in attribute comprehension, with performance drops particularly for abstract attributes like affordance and property, and demonstrate that simply enlarging the vocabulary or transferring OV-3D methods to GOV-3D is insufficient. The paper also analyzes the impact of query form, vocabulary size, and reveals the potential of attribute-aware reasoning, including leveraging LLMs for attribute-to-class mapping and incorporating attribute knowledge into visual-language models. Overall, OpenScan provides a robust platform for diagnosing and guiding improvements in generalized open-vocabulary 3D scene understanding and suggests promising directions for integrating structured attribute knowledge into 3D perception systems.
Abstract
Open-vocabulary 3D scene understanding (OV-3D) aims to localize and classify novel objects beyond the closed set of object classes. However, existing approaches and benchmarks primarily focus on the open vocabulary problem within the context of object classes, which is insufficient in providing a holistic evaluation to what extent a model understands the 3D scene. In this paper, we introduce a more challenging task called Generalized Open-Vocabulary 3D Scene Understanding (GOV-3D) to explore the open vocabulary problem beyond object classes. It encompasses an open and diverse set of generalized knowledge, expressed as linguistic queries of fine-grained and object-specific attributes. To this end, we contribute a new benchmark named \textit{OpenScan}, which consists of 3D object attributes across eight representative linguistic aspects, including affordance, property, and material. We further evaluate state-of-the-art OV-3D methods on our OpenScan benchmark and discover that these methods struggle to comprehend the abstract vocabularies of the GOV-3D task, a challenge that cannot be addressed simply by scaling up object classes during training. We highlight the limitations of existing methodologies and explore promising directions to overcome the identified shortcomings.
