NightAdapter: Learning a Frequency Adapter for Generalizable Night-time Scene Segmentation

Night-time scene segmentation is a critical yet challenging task in the real-world applications, primarily due to the complicated lighting conditions. However, existing methods lack sufficient generalization ability to unseen nighttime scenes with varying illumination. In light of this issue, we focus on investigating generalizable paradigms for night-time scene segmentation and propose an efficient fine-tuning scheme, dubbed NightAdapter, alleviating the domain gap across various scenes. Interestingly, different properties embedded in the day-time and night-time features can be characterized by the bands after discrete sine transform, which can be categorized into illumination-sensitive/-insensitive bands. Hence, our NightAdapter is powered by two appealing designs: (1) Illumination-Insensitive Band Adaptation that provides a foundation for understanding the prior, enhancing the robustness to illumination shifts; (2) Illumination-Sensitive Band Adaptation that fine-tunes the randomized frequency bands, mitigating the domain gap between the day-time and various night-time scenes. As a consequence, illumination-insensitive enhancement improves the domain invariance, while illumination-sensitive diminution strengthens the domain shift between different scenes. NightAdapter yields significant improvements over the state-of-the-art methods under various day-to-night, night-to-night, and in-domain night segmentation experiments. Source code is available at https://github.com/BiQiWHU/NightAdapter.