Understanding Identity Continuity in Thermal Video through Scene-Level Consistency

2026-06-01

AI Summary

This work addresses the challenges of fragmented trajectories and poor identity continuity in thermal multi-object tracking, which stem from weak appearance cues and frequent detection interruptions. Building upon the YOLOv8 and SORT baseline, the authors propose a lightweight post-processing module that integrates online short-gap remapping with offline trajectory relinking driven by spatio-temporal, motion, and boundary cues. This approach significantly enhances identity preservation without relying on complex re-identification models or online association mechanisms. Experimental results on the PBVS thermal MOT benchmark demonstrate that the method improves IDF1 from 82.25 to 84.93 while maintaining stable MOTA, underscoring the critical role of scene-level spatio-temporal consistency in sustaining identity continuity in thermal video tracking.

Abstract

Thermal pedestrian MOT remains challenging because weak appearance cues and frequent detection interruptions cause severe trajectory fragmentation. We study whether lightweight post-processing can recover identity continuity without relying on heavy re-identification models or complex online association. Starting from a YOLOv8 and SORT baseline, we add a modular identity-repair backend consisting of online short-gap remapping and offline tracklet relinking based on temporal, spatial, motion, and border cues. Controlled ablations on a fixed validation split and evaluation on the official PBVS Thermal Pedestrian MOT benchmark show that the main identity gains arise from conservative relinking, improving IDF1 from 82.25 to 84.93 while preserving MOTA, whereas many heuristic thresholds remain stable across broad operating ranges. These results suggest that, in low-information thermal imagery, robust identity recovery can be achieved more effectively through high-precision trajectory relinking than through increasing tracker complexity. These results provide a controlled analysis of identity recovery in thermal video, showing that scene-level spatial-temporal consistency plays a dominant role in identity continuity compared to local frame-to-frame association.

Problem

• thermal pedestrian MOT
• identity continuity
• trajectory fragmentation
• appearance cues
• detection interruptions

Innovation

• thermal pedestrian MOT
• identity continuity
• trajectory relinking
• scene-level consistency
• lightweight post-processing