FreqSpatNet: Frequency and Spatial Dual-Domain Collaborative Learning for Low-Light Image Enhancement

Low-light images often contain noise due to the conditions under which they are taken. Fourier transform can reduce this noise in frequency while preserving the image detail embedded in the low-frequency components. Existing low-light image-enhancement methods based on CNN frameworks often fail to extract global feature information and introduce excessive noise, resulting in detail loss. To solve the above problems, we propose a low-light image-enhancement framework and achieve detail restoration and denoising by using Fourier transform. In addition, we design a dual-domain enhancement strategy, which cooperatively utilizes global frequency-domain feature extraction to improve the overall brightness of the image and the amplitude modulation of the spatial-domain convolution operation to perform local detail refinement to improve the quality of the image by suppressing noise, enhancing the contrast, and preserving the texture at the same time. Extensive experiments on low-light datasets show that our results outperform mainstream methods, especially in maintaining natural color distributions and recovering fine-grained details under extreme lighting conditions. We adopted two evaluation indicators, PSNR and SSIM. Our method improved the PSNR by 4.37% compared to the Restormer method and by 1.76% compared to the DRBN method.