Feature-Augmented Deep Networks for Multiscale Building Segmentation in High-Resolution UAV and Satellite Imagery
Chintan B. Maniyar, Minakshi Kumar, Gengchen Mai
TL;DR
This paper addresses building footprint segmentation from high-resolution RGB imagery where spectral similarity and shadows degrade accuracy. It introduces a feature-augmented multiscale framework using guiding features derived from RGB channels (Sobel edges, VDVI, MBI, and PCA-derived PC1) and a dynamic Res-U-Net trained with a Combo-Loss, defined as $ComboLoss = BCE_{Loss} + \alpha \times Dice_{Loss}$ with $\alpha=1$, plus training policies including cyclical learning rates and SuperConvergence. On a held-out WorldView-3 image the method achieved $96.5\%$ accuracy, $F1$-score $=0.86$, and an IoU $=0.80$, outperforming RGB-based benchmarks. Key contributions include assembling a multiscale RGB UAV/satellite dataset (0.4–2.7 m), three band composites CB0/CB1/CB2, and demonstrating training-time reductions via CLR and SC.
Abstract
Accurate building segmentation from high-resolution RGB imagery remains challenging due to spectral similarity with non-building features, shadows, and irregular building geometries. In this study, we present a comprehensive deep learning framework for multiscale building segmentation using RGB aerial and satellite imagery with spatial resolutions ranging from 0.4m to 2.7m. We curate a diverse, multi-sensor dataset and introduce feature-augmented inputs by deriving secondary representations including Principal Component Analysis (PCA), Visible Difference Vegetation Index (VDVI), Morphological Building Index (MBI), and Sobel edge filters from RGB channels. These features guide a Res-U-Net architecture in learning complex spatial patterns more effectively. We also propose training policies incorporating layer freezing, cyclical learning rates, and SuperConvergence to reduce training time and resource usage. Evaluated on a held-out WorldView-3 image, our model achieves an overall accuracy of 96.5%, an F1-score of 0.86, and an Intersection over Union (IoU) of 0.80, outperforming existing RGB-based benchmarks. This study demonstrates the effectiveness of combining multi-resolution imagery, feature augmentation, and optimized training strategies for robust building segmentation in remote sensing applications.
