Frequency-Decomposed INR for NIR-Assisted Low-Light RGB Image Denoising

TL;DR

This paper introduces FDINR, a frequency-decomposed neural approach leveraging NIR guidance for improved low-light RGB image denoising, effectively restoring details and reducing artifacts.

Contribution

It proposes a novel frequency decoupling framework with cross-modal supervision and adaptive loss, enhancing low-light image restoration beyond existing methods.

Findings

Outperforms existing methods in arbitrary-resolution reconstruction.

Effectively restores luminance and structural details in low-light images.

Reduces artifacts and color distortion in denoised images.

Abstract

Addressing the issues of severe noise and high frequency structural degradation in visible images under low-light conditions, this paper proposes a Near Infrared (NIR) aided low light image restoration method based on Frequency Decoupled Implicit Neural Representation (FDINR). Based on the statistical prior of RGB-NIR cross-modal frequency correlations, specifically that low-frequency RGB signals are more reliable, whereas high frequency NIR signals exhibit higher correlation, we explicitly decompose images into distinct frequency components via multi-scale wavelet transforms and construct a dual-branch implicit neural representation framework. Within this framework, we design a cross modal differentiated frequency supervision mechanism, leveraging low light RGB to guide the reconstruction of low frequency luminance and color, and utilizing high-SNR NIR signals to constrain the generation of high frequency texture details, thereby achieving complementary advantages in the frequency domain. Furthermore, an uncertainty-based adaptive weighting loss function is introduced to automatically balance the contributions of different frequency tasks, solving the problems of color distortion and artifacts caused by rigid fusion in the spatial domain common in traditional methods. Experimental results demonstrate that FD-INR not only effectively restores image luminance consistency and structural details but also, benefitting from its implicit continuous representation, outperforms existing methods in arbitrary-resolution reconstruction tasks, significantly enhancing the reliability of low light perception.