DEC: Low-Bitrate Perceptual Restoration-aware Compression via Decoupled Energy-Complementary Method

Despite the rapid progress of restoration-aware compression, existing studies still face challenges in low-bitrate restoration scenarios. Real-world image acquisition is inevitably affected by degradations, such as noise, blur, and adverse weather, while subsequent compression further reduces perceptual quality. These coupled degradations make it difficult to recover high-quality images from compact bitstreams. To address this issue, we propose a Decoupled Energy-Complementary method for low-bitrate perceptual restoration-aware compression (DEC). DEC jointly considers acquisition distortions and compression effects within a unified restoration framework. It adopts a decoupled dual-branch architecture with a MainInfo Branch and a SideInfo Branch. The MainInfo Branch preserves structural information for reliable reconstruction, whereas the SideInfo Branch compactly encodes boundary and texture cues with only a few additional bits. These two branches form a compact but informative representation that balances compression efficiency and restoration quality. Extensive experiments show that the SideInfo Branch enhances local restoration details across bitrates, while the MainInfo Branch maintains structural fidelity. Overall, DEC achieves an average 35.49% BD-rate reduction with consistent LPIPS gains over state-of-the-art restoration-aware compression methods, confirming its efficiency and visual quality.