Low-light image enhancement techniques have significantly progressed, but unstable image quality recovery and unsatisfactory visual perception are still significant challenges. To solve these problems, we propose a novel and robust low-light image enhancement method via CLIP-Fourier guided wavelet diffusion, abbreviated as CFWD. Specifically, the CFWD leverages multimodal visual-language information in the frequency domain space created by multiple wavelet transforms to guide the enhancement process. Multiscale supervision across different modalities facilitates the alignment of image features with semantic features during the wavelet diffusion process, effectively bridging the gap between the degraded and normal domains. Moreover, to further promote the effective recovery of the image details, we combine the Fourier transform based on the wavelet transform and construct a hybrid high-frequency perception module (HFPM) with a significant perception of the detailed features. This module avoids the diversity confusion of the wavelet diffusion process by guiding the fine-grained structure recovery of the enhancement results to achieve favourable metrics and perceptually oriented enhancement. Extensive quantitative and qualitative experiments on publicly available real-world benchmarks show that our approach outperforms existing state-of-the-art methods, achieving significant progress in image quality and noise suppression. The project code is available at https://github.com/hejh8/CFWD .

Low-lightimage enhancement methods are difficult to fit the complex nonlinear relationship between normal and low-light images due to uneven illumination and noise effects. The recently proposed Kolmogorov-Arnold networks (KANs) feature spline-based convolutional layers and learnable activation functions, which can effectively capture nonlinear dependencies. In this paper, we design a KAN-Block based on KANs and innovatively apply it to low-light image enhancement. This method effectively alleviates the limitations of current methods constrained by linear network structures and lack of interpretability, further demonstrating the potential of KANs in low-level vision tasks. Given the poor perception of current low-light image enhancement methods and the stochastic nature of the inverse diffusion process, we further introduce frequency-domain perception for visually oriented enhancement. Extensive experiments demonstrate the competitive performance of our method on benchmark datasets.

Low-light image enhancement is an essential task in image restoration. Inspired by the diffusion model, the related methods have achieved remarkable results in low-level visual tasks. However, such methods are susceptible to large-scale images, generating problems such as overconsumption of resources and low recovery efficiency. To address this, we propose a detail-guided latent space low-light image enhancement diffusion model called DLDiff. Leveraging the generative power of the latent diffusion model, we explore ways to speed up inference better while producing excellent perceptual fidelity. Specifically, we initially employ the latent diffusion model to transform low-light image features into a latent space representation, thereby reducing computational resource consumption. Next, we design a lightweight detail prompt module that combines cross-convolution and vast-receptive-field convolution blocks. This module enhances the fine-grained details of the image, effectively supplements multiscale feature information, and minimizes feature loss in the latent space. Furthermore, we devise the content-aware loss group to facilitate learning noise and image information, enhancing the model's recovery capability, guiding stable sampling, and constraining diverse content generation. Through extensive experiments, we demonstrate the model's significant efficiency and quality advantages in low-light image enhancement tasks. The code is available at https://github.com/Yuii666/DLDiff .

Due to the singularity of real-world paired datasets and the complexity of low-light environments, this leads to supervised methods lacking a degree of scene generalisation. Meanwhile, limited by poor lighting and content guidance, existing zero-shot methods cannot handle unknown severe degradation well. To address this problem, we will propose a new zero-shot low-light enhancement method to compensate for the lack of light and structural information in the diffusion sampling process by effectively combining the wavelet and Fourier frequency domains to construct rich a priori information. The key to the inspiration comes from the similarity between the wavelet and Fourier frequency domains: both light and structure information are closely related to specific frequency domain regions, respectively. Therefore, by transferring the diffusion process to the wavelet low-frequency domain and combining the wavelet and Fourier frequency domains by continuously decomposing them in the inverse process, the constructed rich illumination prior is utilised to guide the image generation enhancement process. Sufficient experiments show that the framework is robust and effective in various scenarios. The code will be available at: https://github.com/hejh8/Joint-Wavelet-and-Fourier-priors-guided-diffusion.