Wavelet-Based Bi-Dimensional Aggregation Network for SAR Image Change Detection

Jiangwei Xie, Feng Gao, Xiaowei Zhou, Junyu Dong

Abstract: Synthetic aperture radar (SAR) image change detection is critical in remote sensing image analysis. Recently, the attention mechanism has been widely used in change detection tasks. However, existing attention mechanisms often use downsampling operations such as average pooling on the key and value components to enhance computational efficiency. These irreversible operations result in the loss of high-frequency components and other important information. To address this limitation, we develop wavelet-based bi-dimensional aggregation network (WBANet) for SAR image change detection. We design a wavelet-based self-attention block that includes discrete wavelet transform (DWT) and inverse DWT (IDWT) operations on key and value components. Hence, the feature undergoes downsampling without any loss of information, while simultaneously enhancing local contextual awareness through an expanded receptive field. In addition, we have incorporated a bi-dimensional aggregation module (BAM) that boosts the nonlinear representation capability by merging spatial and channel information via broadcast mechanism. Experimental results on three SAR datasets demonstrate that our WBANet significantly outperforms contemporary state-of-the-art methods. Specifically, our WBANet achieves 98.33%, 96.65%, and 96.62% of percentage of correct classification (PCC) on the respective datasets, highlighting its superior performance. Source codes are available at https://github.com/summitgao/WBANet .