To enable robots to use tools, the initial step is teaching robots to employ dexterous gestures for touching specific areas precisely where tasks are performed. Affordance features of objects serve as a bridge in the functional interaction between agents and objects. However, leveraging these affordance cues to help robots achieve functional tool grasping remains unresolved. To address this, we propose a granularity-aware affordance feature extraction method for locating functional affordance areas and predicting dexterous coarse gestures. We study the intrinsic mechanisms of human tool use. On one hand, we use fine-grained affordance features of object-functional finger contact areas to locate functional affordance regions. On the other hand, we use highly activated coarse-grained affordance features in hand-object interaction regions to predict grasp gestures. Additionally, we introduce a model-based post-processing module that includes functional finger coordinate localization, finger-to-end coordinate transformation, and force feedback-based coarse-to-fine grasping. This forms a complete dexterous robotic functional grasping framework GAAF-Dex, which learns Granularity-Aware Affordances from human-object interaction for tool-based Functional grasping in Dexterous Robotics. Unlike fully-supervised methods that require extensive data annotation, we employ a weakly supervised approach to extract relevant cues from exocentric (Exo) images of hand-object interactions to supervise feature extraction in egocentric (Ego) images. We have constructed a small-scale dataset, FAH, which includes near 6K images of functional hand-object interaction Exo- and Ego images of 18 commonly used tools performing 6 tasks. Extensive experiments on the dataset demonstrate our method outperforms state-of-the-art methods. The code will be made publicly available at https://github.com/yangfan293/GAAF-DEX.

为了使机器人能够使用工具，我们提出了一种从人-物互动中学习粒度感知功能性工具握持的方法，该方法利用物体的显著特征来定位功能性作用区域并预测熟练的粗略手势。通过弱监督学习从外心图像中提取相关线索以监督视角中的特征提取，我们的方法在功能手-物互动图像数据集上表现出优于现有方法的效果。

从人物-物体互动中学习粒度感知特性，为灵巧机器人的基于工具的功能抓取提供支持