Scale- and Shape-Aware Network With Prediction Decoupling for Building Fine-Grained Change Detection

Building change detection (BCD) is a hot topic in geoscience and remote sensing (RS) with widespread applications. However, most existing BCD methods only focus on areas where changes have occurred, but ignore the change statuses. To address this problem, a building fine-grained change detection (BFCD) task is further explored in this work, which aims to judge the time-related “disappeared”, “appeared”, and “rebuilt” change types of buildings. Meanwhile, a scale- and shape-aware network (S2Net) with prediction decoupling is designed. Firstly, a prediction decoupling framework with dual decoders is built to ensure the prediction consistency with the temporal order of bi-temporal images. Secondly, considering the rebuilt type is the changes between building instances, which are often reflected in the scale and shape differences of the buildings. Thereby, a scale-aware module (ScAM) and a shape-aware module (ShAM) are designed. These two modules help extract the discriminative features of buildings with different scales and shapes for subsequent change detection (CD). In addition, two BCD datasets widely used, LEVIR-CD+ and WHU-CD, are relabeled in this work to support the study of BFCD. Experimental results show that S2Net achieves competitive performance, and its effectiveness is confirmed. The code and datasets will be publicly available at https://github.com/ptdoge/S2Net.