Decouple to Reconcile: Explicit Inter- and Intra-Exposure Motion Modeling for Night Image Restoration

Photon scarcity in low-light environments makes high-quality night image restoration from a single exposure inherently challenging. Dual-exposure imaging offers an effective solution by exploiting the complementary characteristics of short- and long-exposure images. However, motion-induced inter-frame misalignment and intra-exposure blur hinder their effective collaborative restoration. To this end, we propose an explicit inter- and intra-exposure motion decoupling framework that separately models cross-exposure displacement and within-exposure motion blur, enabling accurate alignment and collaborative restoration of complementary dual-exposure information. Specifically, I2EM follows a two-stage decouple-to-reconcile paradigm. The decoupling stage separately models cross-exposure displacement and intra-exposure blur using bidirectional optical flow and exposure-specific motion-conditioned kernels. The reconciliation stage restores and aligns long-exposure features against the sharper short-exposure reference, then integrates complementary information through confidence-guided multi-scale fusion and residual denoising. On D2, I2EM achieves state-of-the-art performance among the compared methods, demonstrating the effectiveness of explicit inter- and intra-exposure motion modeling for dual-exposure night-image restoration.