RFCNet: Enhancing urban segmentation using regularization, fusion, and completion

Abstract

Image segmentation is a fundamental task that has benefited from recent advances in machine learning. One type of segmentation, of particular interest to computer vision, is that of urban segmentation. Although recent solutions have leveraged on deep neural networks, approaches usually do not consider regularities appearing in facade structures (e.g., windows are often in groups of similar alignment, size, or spacing patterns) as well as additional urban structures such as building footprints and roofs. Moreover, both satellite and street-view images are often noisy and occluded, thus getting the complete structure segmentation from a partial observation is difficult. Our key observations are that facades and other urban structures exhibit regular structures, and additional views are often available. In this paper, we present a novel framework (RFCNet) that consists of three modules to achieve multiple goals. Specifically, we propose Regularization to improve the regularities given an initial segmentation, Fusion that fuses multiple views of the segmentation, and Completion that can infer the complete structure if necessary. Experimental results show that our method outperforms previous state-of-the-art methods quantitatively and qualitatively for multiple facade datasets. Furthermore, by applying our framework to other urban structures (e.g., building footprints and roofs), we demonstrate our approach can be generalized to various pattern types.