Positive-Sample-Free Object Tracking via a Soft Constraint

Most of the existing bounding box-based trackers rely on a classification subnetwork and a regression subnetwork to predict the location and scale of the bounding box. They learn the classification subnetwork by processing each sample individually and applying the suggested classification confidence to produce the final prediction. They typically involve heuristic positive sample configurations, which inevitably introduce mislabelled training samples and therefore deteriorate their tracking performance. Moreover, the parallel prediction of the bounding box position and scale may lead to misalignment of classification and regression. To address these issues,we propose a simple yet effective soft constraint-based tracking framework without positive samples (named SoftCT). SoftCT adaptively senses the target's pixel position through a soft constraint mechanism, which eliminates potential performance gaps caused by artificially marking the target's pixel position. In addition, SoftCT computes the state of the bounding box by aggregating such positional information, thereby allowing the tracker to avoid misalignment in classification and regression due to uninformed communication. Specifically, SoftCT directly senses the position of the target pixel and fuses this information into the bounding box prediction, rather than requiring explicit annotation or regression of the target pixel. Extensive experiments on six tracking benchmarks including GOT-10k, TrackingNet, LaSOT, UAV123, LaSOText and TNL2K demonstrate that our tracker achieves state-of-the-art performance, confirming its effectiveness and efficiency.