Most previous progress in object tracking is realized in daytime scenes with favorable illumination. State-of-the-arts can hardly carry on their superiority at night so far, thereby considerably blocking the broadening of visual tracking-related unmanned aerial vehicle (UAV) applications. To realize reliable UAV tracking at night, a spatial-channel Transformer-based low-light enhancer (namely SCT), which is trained in a novel task-inspired manner, is proposed and plugged prior to tracking approaches. To achieve semantic-level low-light enhancement targeting the high-level task, the novel spatial-channel attention module is proposed to model global information while preserving local context. In the enhancement process, SCT denoises and illuminates nighttime images simultaneously through a robust non-linear curve projection. Moreover, to provide a comprehensive evaluation, we construct a challenging nighttime tracking benchmark, namely DarkTrack2021, which contains 110 challenging sequences with over 100 K frames in total. Evaluations on both the public UAVDark135 benchmark and the newly constructed DarkTrack2021 benchmark show that the task-inspired design enables SCT with significant performance gains for nighttime UAV tracking compared with other top-ranked low-light enhancers. Real-world tests on a typical UAV platform further verify the practicability of the proposed approach. The DarkTrack2021 benchmark and the code of the proposed approach are publicly available at https://github.com/vision4robotics/SCT.

翻译：大多数目标跟踪领域的先前进展都是在光照良好的白天场景中实现的。迄今为止，最先进的方法在夜间很难延续其优越性，从而严重阻碍了与视觉跟踪相关的无人机应用的拓展。为实现可靠的夜间无人机跟踪，本文提出了一种基于空间-通道Transformer的低光照增强器（简称SCT），该增强器采用新颖的任务启发式训练方式，并作为预处理模块接入跟踪方法之前。为了针对高层级任务实现语义级别的低光照增强，我们提出了新颖的空间-通道注意力模块，以在保留局部上下文的同时建模全局信息。在增强过程中，SCT通过鲁棒的非线性曲线投影同时完成夜间图像的去噪和增亮。此外，为提供全面评估，我们构建了一个具有挑战性的夜间跟踪基准——DarkTrack2021，该基准包含110个具有挑战性的序列，总计超过10万帧。在公开的UAVDark135基准以及新构建的DarkTrack2021基准上的评估表明，与其他顶级低光照增强器相比，任务启发式设计使SCT在夜间无人机跟踪中实现了显著的性能提升。在典型无人机平台上的真实世界测试进一步验证了所提出方法的实用性。DarkTrack2021基准及所提出方法的代码已在https://github.com/vision4robotics/SCT公开提供。