FRBNet: Revisiting Low-Light Vision through Frequency-Domain Radial Basis Network

TL;DR

FRBNet introduces a frequency-domain radial basis network that enhances illumination-invariant features for low-light vision tasks, significantly improving detection and segmentation performance without altering existing loss functions.

Contribution

The paper extends the classical Lambertian model to the frequency domain and proposes FRBNet, a novel trainable module for better low-light image analysis.

Findings

Achieves +2.2 mAP in dark object detection

Improves nighttime segmentation by +2.9 mIoU

Demonstrates superior performance across various downstream tasks

Abstract

Low-light vision remains a fundamental challenge in computer vision due to severe illumination degradation, which significantly affects the performance of downstream tasks such as detection and segmentation. While recent state-of-the-art methods have improved performance through invariant feature learning modules, they still fall short due to incomplete modeling of low-light conditions. Therefore, we revisit low-light image formation and extend the classical Lambertian model to better characterize low-light conditions. By shifting our analysis to the frequency domain, we theoretically prove that the frequency-domain channel ratio can be leveraged to extract illumination-invariant features via a structured filtering process. We then propose a novel and end-to-end trainable module named \textbf{F}requency-domain \textbf{R}adial \textbf{B}asis \textbf{Net}work (\textbf{FRBNet}), which integrates the frequency-domain channel ratio operation with a learnable frequency domain filter for the overall illumination-invariant feature enhancement. As a plug-and-play module, FRBNet can be integrated into existing networks for low-light downstream tasks without modifying loss functions. Extensive experiments across various downstream tasks demonstrate that FRBNet achieves superior performance, including +2.2 mAP for dark object detection and +2.9 mIoU for nighttime segmentation. Code is available at: https://github.com/Sing-Forevet/FRBNet.