BIBED-Seg: Block-in-Block Edge Detection Network for Guiding Semantic Segmentation Task of High-Resolution Remote Sensing Images

Edge optimization of semantic segmentation results is a challenging issue in remote sensing image processing. This article proposes a semantic segmentation model guided by a block-in-block edge detection network named BIBED-Seg. This is a two-stage semantic segmentation model, where edges are extracted first and then segmented. We do two key works: The first work is edge detection, and we present BIBED, a block-in-block edge detection network, to extract the accurate boundary features. Here, the edge detection of multiscale feature fusion is first realized by creating the block-in-block residual network structure and devising the multilevel loss function. Second, we add the channel and spatial attention module into the residual structure to improve high-resolution remote sensing images' boundary positioning and detection accuracy by focusing on their channel and spatial dimensions. Finally, we evaluate our method on International Society for Photogrammetry and Remote Sensing (ISPRS) Potsdam and Vaihingen data sets and obtain ODS F-measure of 0.6671 and 0.7432, higher than other excellent edge detection methods. The second work is two-stage segmentation. First, the proposed BIBED is individually pretrained, and subsequently, the pretrained model is introduced into the entire segmentation network to extract boundary features. In the second segmentation stage, the edge detection network is used to constrain semantic segmentation results by loss cycles and feature bootstrapping. Our best model obtains the OA of 90.2%, 87.7%, and 81.5%, the IOU of 76.0%, 69.6%, and 61.3% on the ISPRS and WHDLD datasets, respectively.