MSR-TRACK: MITIGATING SEARCH REPRESENTATION DILUTION IN INFRARED ANTI-UAV TRACKING

Reliable infrared anti-UAV tracking is difficult because aerial targets occupy few pixels, provide weak appearance cues, and are frequently obscured by clutter, thermal distractors, rapid motion, or temporary disappearance. Although adaptive local trackers enlarge the search area to recover targets, resizing the larger crop to a fixed input shrinks the target’s relative scale and admits additional background. We call this effect search representation dilution. To address it, we introduce MSR-Track, which enhances search representations at complementary token and spatial stages. Lightweight Token Refinement (LTR) recalibrates search tokens before template–search interaction without altering their number or spatial order. The Multi-Scale Response Enhancement (MSRE) head aggregates fine-scale evidence and broad context to reinforce weak UAV responses before bounding-box prediction. MSR-Track obtains 62.5% AUC, 86.1% Precision, and 82.2% Normalized Precision on Anti-UAV410, exceeding our FocusTrack-SRA by 2.3, 2.9, and 2.7 points while adding little computation. Tests on Anti-UAV300 and CST Anti-UAV demonstrate cross-dataset generalization under unseen distributions.