Multiple Object Tracking (MOT) is a critical task in computer vision with a wide range of practical applications. However, current methods often use a uniform approach for associating all targets, overlooking the varying conditions of each target. This can lead to performance degradation, especially in crowded scenes with dense targets. To address this issue, we propose a novel Condition-Aware Tracking method (CATrack) to differentiate the appearance feature flow for targets under different conditions. Specifically, we propose three designs for data association and feature update. First, we develop an Adaptive Appearance Association Module (AAAM) that selects suitable track templates based on detection conditions, reducing association errors in long-tail cases like occlusions or motion blur. Second, we design an ambiguous track filtering Selective Update strategy (SU) that filters out potential low-quality embeddings. Thus, the noise accumulation in the maintained track feature will also be reduced. Meanwhile, we propose a confidence-based Adaptive Exponential Moving Average (AEMA) method for the feature state transition. By adaptively adjusting the weights of track and detection embeddings, our AEMA better preserves high-quality target features. By integrating the above modules, CATrack enhances the discriminative capability of appearance features and improves the robustness of appearance-based associations. Extensive experiments on the MOT17 and MOT20 benchmarks validate the effectiveness of the proposed CATrack. Notably, the state-of-the-art results on MOT20 demonstrate the superiority of our method in highly crowded scenarios.

Open-vocabulary multi-object tracking (OVMOT) is a cutting research direction within the multi-object tracking field. It employs large multi-modal models to effectively address the challenge of tracking unseen objects within dynamic visual scenes. While models require robust domain generalization and temporal adaptability, OVTrack, the only existing open-vocabulary multi-object tracker, relies solely on static appearance information and lacks these crucial adaptive capabilities. In this paper, we propose OVSORT, a new framework designed to improve domain generalization and temporal information processing. Specifically, we first propose the Adaptive Contextual Normalization (ACN) technique in OVSORT, which dynamically adjusts the feature maps based on the dataset's statistical properties, thereby fine-tuning our model's to improve domain generalization. Then, we introduce motion cues for the first time. Using our Joint Motion and Appearance Tracking (JMAT) strategy, we obtain a joint similarity measure and subsequently apply the Hungarian algorithm for data association. Finally, our Hierarchical Adaptive Feature Update (HAFU) strategy adaptively adjusts feature updates according to the current state of each trajectory, which greatly improves the utilization of temporal information. Extensive experiments on the TAO validation set and test set confirm the superiority of OVSORT, which significantly improves the handling of novel and base classes. It surpasses existing methods in terms of accuracy and generalization, setting a new state-of-the-art for OVMOT.

Entropy search and its derivative methods are one class of Bayesian Optimization methods that achieve active exploration of black-box functions. They maximize the information gain about the position in the input space where the black-box function gets the global optimum. However, existing entropy search methods suffer from harassment caused by high dimensional optimization problems. On the one hand, the computation for estimating entropies increases exponentially as dimensions increase, which limits the applicability of entropy search to high dimensional problems. On the other hand, many high-dimensional problems have the property that a large number of dimensions have little influence on the objective function, but currently there is no compress mechanism to exclude these redundant dimensions. In this work, we propose Active Compact Entropy Search (AcCES) to fix these defects. Under the guidance of historical evaluation, AcCES actively explores the prevalent inter-dimensional correlations by maximizing the linear or non-linear relationships that may exist between dimensions in the acquisition function, which is ignored by existing Bayesian Optimization methods. In order to build a more compact input space, redundant dimensions are compressed by exploiting inter-dimensional correlations. Experiments demonstrate that AcCES achieves higher query efficiency and optimal results than existing entropy search methods.

Vehicle Re-Identification targets at searching for vehicle instances of the same identity with a given query. It has gained an increasing attention recently with a wide application prospects in video surveillance and intelligent transportation. The main challenge lies in how to distinguish the subtle differences between different vehicles, while capturing the slight similarity between the instance of the same vehicle in different viewpoints or illuminations. To this end, most existing methods focus on learning discriminative global representations, which leave the unique local details such as stickers, inspection labels and driver wearing being unexploited. In this paper, we present a novel coarse-to-fine scheme that aggregates global and local visual representations to boost the retrieval accuracy. Specifically, a multi-task learning framework combining an Attribute Learning branch and a Deep Ranking branch (termed ALDR) is first adopted to learn robust global features, which produces an initial ranking list. Then the local similarities between image patches in the initial ranking list and in the query is computed via a Multi-Channel and Multi-Scale Siamese network (termed MCMS-Siam). Finally, the retrieval result is returned after re-ranking the initial list according to such a combination of global and local similarities. Experimental results on the widely-used VehicleID dataset and VECH-WILD dataset demonstrate the merits of the proposed method over the state-of-the-art methods.

Most existing fine-grained image retrieval schemes are built based upon deep feature learning paradigms, which typically leverage the feature maps of the last convolutional layer as features. However, such representation focuses only on the global information of the object, leaving the local details unexploited, which is however crucial to identifying subtle differences for fine-grained retrieval. In this paper, we have discovered that the mid-level feature map roles as local salient regions, which well complements the existing global feature representations. To this end, a multi-layer framework is proposed to integrate both local and global representations with generalized mean (GeM) pooling and attention mechanism, trained with the proposed N-pair Center loss to learn more discriminative features. By doing so, state-of-the-art performance can be achieved without using the hard or negative example minings. In the experiments, our approach outperforms favourably compared to the current state-of-the-art methods on the CUB-200-2011, CARS196 and In-shop Clothes Retrieval datasets.