ObjFormer: Learning Land-Cover Changes From Paired OSM Data and Optical High-Resolution Imagery via Object-Guided Transformer
arXiv:2310.02674 · doi:10.1109/TGRS.2024.3410389
Abstract
Optical high-resolution imagery and OSM data are two important data sources of change detection (CD). Previous related studies focus on utilizing the information in OSM data to aid the CD on optical high-resolution images. This paper pioneers the direct detection of land-cover changes utilizing paired OSM data and optical imagery, thereby expanding the scope of CD tasks. To this end, we propose an object-guided Transformer (ObjFormer) by naturally combining the object-based image analysis (OBIA) technique with the advanced vision Transformer architecture. This combination can significantly reduce the computational overhead in the self-attention module without adding extra parameters or layers. ObjFormer has a hierarchical pseudo-siamese encoder consisting of object-guided self-attention modules that extracts multi-level heterogeneous features from OSM data and optical images; a decoder consisting of object-guided cross-attention modules can recover land-cover changes from the extracted heterogeneous features. Beyond basic binary change detection, this paper raises a new semi-supervised semantic change detection task that does not require any manually annotated land-cover labels to train semantic change detectors. Two lightweight semantic decoders are added to ObjFormer to accomplish this task efficiently. A converse cross-entropy loss is designed to fully utilize negative samples, contributing to the great performance improvement in this task. A large-scale benchmark dataset called OpenMapCD containing 1,287 samples covering 40 regions on six continents is constructed to conduct detailed experiments. The results show the effectiveness of our methods in this new kind of CD task. Additionally, case studies in Japanese cities demonstrate the framework's generalizability and practical potential. The OpenMapCD and source code are available in https://github.com/ChenHongruixuan/ObjFormer
Accepted by IEEE TGRS
References in corpus (9)
- Decoupled Weight Decay Regularization
- Gaussian Error Linear Units (GELUs)
- Remote Sensing Image Change Detection with Transformers
- Bi-Temporal Semantic Reasoning for the Semantic Change Detection in HR Remote Sensing Images
- OpenStreetMap: Challenges and Opportunities in Machine Learning and Remote Sensing
- Change Guiding Network: Incorporating Change Prior to Guide Change Detection in Remote Sensing Imagery
- Joint Spatio-Temporal Modeling for the Semantic Change Detection in Remote Sensing Images
- Unsupervised Multimodal Change Detection Based on Structural Relationship Graph Representation Learning
- How Much Position Information Do Convolutional Neural Networks Encode?