RWNet: A Recursive Wavelet-Driven Network for Deformable Medical Image Registration
摘要
Deformable image registration is crucial for medical imaging tasks such as disease diagnosis and treatment planning. Recent advances have relied on either transformer- or attention-based deep learning registration architectures for dense deformation field estimation, resulting in high complexity but with insufficient granularity. Moreover, the insufficient capability of multi-scale resolution modeling still poses a challenge to the accurate and effective registration of large volume deformations. Therefore, we propose a Recursive Wavelet-driven Network (RWNet) by integrating multi-level wavelet sub-bands and a recursive strategy to facilitate multi-scale deformation representation learning for deformation field prediction. Specifically, a pure convolutional encoder with discrete wavelet transform is developed for deep feature mining at multiple scales with different frequency components without high-weight attentions. Then, a deformation fusion-based field estimation method is carefully designed, which combines the frequency-driven field with the spatially-enhanced one to facilitate the reconstruction of the displacement field. Finally, a step-by-step recursive strategy is adopted by integrating high-level features to iteratively refine transformations in a coarse-to-fine manner. Extensive experiments on two publicly available brain MRI datasets demonstrate the superior performance against existing registration methods.