Into the Fog: Evaluating Multiple Object Tracking Robustness

State-of-the-art (SOTA) trackers have shown remarkable Multiple Object Tracking (MOT) performance when trained and evaluated on current benchmarks. However, these benchmarks primarily consist of clear scenarios, overlooking adverse atmospheric conditions such as fog, haze, smoke and dust. As a result, the robustness of SOTA trackers remains underexplored. To address these limitations, we propose a pipeline for physic-based volumetric fog simulation in arbitrary real-world MOT dataset utilizing frame-by-frame monocular depth estimation and a fog formation optical model. Moreover, we enhance our simulation by rendering of both homogeneous and heterogeneous fog effects. We propose to use the dark channel prior method to estimate fog (smoke) color, which shows promising results even in night and indoor scenes. We present the leading tracking benchmark MOTChallenge (MOT17 dataset) overlaid by fog (smoke for indoor scenes) of various intensity levels and conduct a comprehensive evaluation of SOTA MOT methods, revealing their limitations under fog and fog-similar challenges.

Identifying and Extracting Pedestrian Behavior in Critical Traffic Situations

A better understanding of interactive pedestrian behavior in critical traffic situations is essential for the development of enhanced pedestrian safety systems. Real-world traffic observations play a decisive role in this, since they represent behavior in an unbiased way. In this work, we present an approach of how a subset of very considerable pedestrian-vehicle interactions can be derived from a camera-based observation system. For this purpose, we have examined road user trajectories automatically for establishing temporal and spatial relationships, using 110h hours of video recordings. In order to identify critical interactions, our approach combines the metric post-encroachment time with a newly introduced motion adaption metric. From more than 11,000 reconstructed pedestrian trajectories, 259 potential scenarios remained, using a post-encroachment time threshold of 2s. However, in 95% of cases, no adaptation of the pedestrian behavior was observed due to avoiding criticality. Applying the proposed motion adaption metric, only 21 critical scenarios remained. Manual investigations revealed that critical pedestrian vehicle interactions were present in 7 of those. They were further analyzed and made publicly available for developing pedestrian behavior models3. The results indicate that critical interactions in which the pedestrian perceives and reacts to the vehicle at a relatively late stage can be extracted using the proposed method.