Real-Scene Image Dehazing via Laplacian Pyramid-Based Conditional Diffusion Model

Recent diffusion models have demonstrated exceptional efficacy across various image restoration tasks, but still suffer from time-consuming and substantial computational resource consumption. To address these challenges, we present LPCDiff, a novel Laplacian Pyramid-based Conditional Diffusion model designed for real-scene image dehazing. LPCDiff leverages the Laplacian pyramid decomposition to decouple the input image into two components: the low-resolution low-pass image and the high-frequency residuals. These components are subsequently reconstructed through a diffusion model and a well-designed high-frequency residual recovery module. With such a strategy, LPCDiff can substantially accelerate inference speed and reduce computational costs without sacrificing image fidelity. In addition, the framework empowers the model to capture intrinsic high-frequency details and low-frequency structural information within the image, resulting in sharper and more realistic haze-free outputs. Moreover, to extract more valuable information from the limited training data, we introduce a low-frequency refinement module to further enhance the intricate details of the final dehazed images. Through extensive experimentation, our method significantly outperforms 12 state-of-the-art approaches on three real-world and one synthetic image dehazing benchmarks. Code is available at https://github.com/yz-wang/LPCDiff.