LEFormer: A Hybrid CNN-Transformer Architecture for Accurate Lake Extraction from Remote Sensing Imagery

Lake extraction from remote sensing imagery is challenging due to the complex shapes of lakes and the presence of noise. Existing methods suffer from blurred segmentation boundaries and poor foreground modeling. In this paper, we propose a hybrid CNN-Transformer architecture, called LEFormer, for accurate lake extraction. LEFormer contains four main modules: CNN encoder, Transformer encoder, cross-encoder fusion, and lightweight decoder. The CNN encoder recovers local spatial information and improves fine-scale details. Simultaneously, the Transformer encoder captures long-range dependencies between sequences of any length, allowing them to obtain global features and context information better. Finally, a lightweight decoder is employed for mask prediction. We evaluate the performance and efficiency of LEFormer on two datasets, the Surface Water (SW) and the Qinghai-Tibet Plateau Lake (QTPL). Experimental results show that LEFormer consistently achieves state-of-the-art (SOTA) performance and efficiency on these two datasets, outperforming existing methods. Specifically, LEFormer achieves 90.86% and 97.42% mIoU on the SW and QTPL datasets with a parameter count of 3.61M, respectively, while being 20x minor than the previous SOTA method.