Xiaojun Peng

Pengzhi Zhong, Xiaoyu Guo, Defeng Huang et al.

In recent years, the field of visual tracking has made significant progress with the application of large-scale training datasets. These datasets have supported the development of sophisticated algorithms, enhancing the accuracy and stability of visual object tracking. However, most research has primarily focused on favorable illumination circumstances, neglecting the challenges of tracking in low-ligh environments. In low-light scenes, lighting may change dramatically, targets may lack distinct texture features, and in some scenarios, targets may not be directly observable. These factors can lead to a severe decline in tracking performance. To address this issue, we introduce LLOT, a benchmark specifically designed for Low-Light Object Tracking. LLOT comprises 269 challenging sequences with a total of over 132K frames, each carefully annotated with bounding boxes. This specially designed dataset aims to promote innovation and advancement in object tracking techniques for low-light conditions, addressing challenges not adequately covered by existing benchmarks. To assess the performance of existing methods on LLOT, we conducted extensive tests on 39 state-of-the-art tracking algorithms. The results highlight a considerable gap in low-light tracking performance. In response, we propose H-DCPT, a novel tracker that incorporates historical and darkness clue prompts to set a stronger baseline. H-DCPT outperformed all 39 evaluated methods in our experiments, demonstrating significant improvements. We hope that our benchmark and H-DCPT will stimulate the development of novel and accurate methods for tracking objects in low-light conditions. The LLOT and code are available at https://github.com/OpenCodeGithub/H-DCPT.

Jihao Long, Xiaojun Peng, Lei Wu

Kernel ridge regression (KRR), also known as the least-squares support vector machine, is a fundamental method for learning functions from finite samples. While most existing analyses focus on the noisy setting with constant-level label noise, we present a comprehensive study of KRR in the noiseless regime -- a critical setting in scientific computing where data are often generated via high-fidelity numerical simulations. We establish that, up to logarithmic factors, noiseless KRR achieves minimax optimal convergence rates, jointly determined by the eigenvalue decay of the associated integral operator and the target function's smoothness. These rates are derived under Sobolev-type interpolation norms, with the $L^2$ norm as a special case. Notably, we uncover two key phenomena: an extra-smoothness effect, where the KRR solution exhibits higher smoothness than typical functions in the native reproducing kernel Hilbert space (RKHS), and a saturation effect, where the KRR's adaptivity to the target function's smoothness plateaus beyond a certain level. Leveraging these insights, we also derive a novel error bound for noisy KRR that is noise-level aware and achieves minimax optimality in both noiseless and noisy regimes. As a key technical contribution, we introduce a refined notion of degrees of freedom, which we believe has broader applicability in the analysis of kernel methods. Extensive numerical experiments validate our theoretical results and provide insights beyond existing theory.