An Informative Path Planning Framework for Active Learning in UAV-Based Semantic Mapping

Unmanned aerial vehicles (UAVs) are frequently used for aerial mapping and general monitoring tasks. Recent progress in deep learning enabled automated semantic segmentation of imagery to facilitate the interpretation of large-scale complex environments. Commonly used supervised deep learning for segmentation relies on large amounts of pixelwise labeled data, which is tedious and costly to annotate. The domain-specific visual appearance of aerial environments often prevents the usage of models pretrained on publicly available datasets. To address this, we propose a novel general planning framework for UAVs to autonomously acquire informative training images for model retraining. We leverage multiple acquisition functions and fuse them into probabilistic terrain maps. Our framework combines the mapped acquisition function information into the UAV's planning objectives. In this way, the UAV adaptively acquires informative aerial images to be manually labeled for model retraining. Experimental results on real-world data and in a photorealistic simulation show that our framework maximizes model performance and drastically reduces labeling efforts. Our map-based planners outperform state-of-the-art local planning.