In recent years, abnormal human behavior recognition has become an attractive research topic of computer vision due to the rapid growth of demand to monitor human activities on closed-circuit television (CCTV) cameras. However, developing a deep learning-based model for abnormal/violent behavior recognition in surveillance systems is still quite challenging and costly due to inadequate data and model complexity. This paper presents an efficient approach to recognize violent behavior such as fighting, sexual harassment, and climbing fence in real-time on a multi-camera-one-edge-device system. Our approach develops a lightweight 3DCNN model trained by an effective optimization process to recognize human behavior from sequence frames of CCTV video signal input. In the optimization method, we utilize two advantages of deep learning techniques of knowledge distillation and contrastive learning to enhance the quality of the lightweight model on recognizing recorded human behaviors, which can help the student network learn distilled information from both the bigger model and contrastive object representations. We also establish a large CCTV human behavior video dataset containing 4,200 abnormal and 24,000 normal videos. The effectiveness of the proposed approach is shown by the high inference performance and impressive results evaluated on both public datasets the RWF-2000 dataset, the UCF101 dataset, and our collected datasets.

Object re-identification (ReID) is prone to errors under variations in scale, illumination, complex background, and object occlusion scenarios. To overcome these challenges, attention mechanisms are employed to focus on the object's characteristics, thereby extracting better discriminative features. This paper introduces a local-global vision transformer (LoGoViT) for object re-identification by learning a hierarchical-level representation from fine-grained (local) to general (global) context features. It comprises two components: (i) shift and shuffle operations to generate robust local features and (ii) local-global module to aggregate the multi-level hierarchy features of an object. Extensive experiments show that our method achieves state-of-the-art on the ReID benchmarks. We further investigate effective augmentation operations and discuss how the patch modifications improve the proposed model's generalization under occlusion scenarios. The source code is available at https://github.com/nguyenphan99/LoGoViT.

Deep metric learning (or simply called metric learning) uses the deep neural network to learn the representation of images, leading to widely used in many applications, e.g. image retrieval and face recognition. In the metric learning approaches, proxy anchor takes advantage of proxy-based and pair-based approaches to enable fast convergence time and robustness to noisy labels. However, in training the proxy anchor, selecting the hyperparameter margin is important to achieve a good performance. This selection requires expertise and is time-consuming. This paper proposes a novel method to learn the margin while training the proxy anchor approach adaptively. The proposed adaptive proxy anchor simplifies the hyperparameter tuning process while advancing the proxy anchor. We achieve state of the art on three public datasets with a noticeably faster convergence time. Our code is available at https: //github.com/tks1998/Adaptive-Proxy-Anchor

As an improvement over the standard simple online real-time tracking (SORT) method, DeepSORT introduces a cascade matching mechanism to track objects during a certain period of occlusion, effectively reducing the number of identity (ID) switches. However, DeepSORT lacks the capability of lost-identities recovery, which enables robustness and performance in face recognition systems. To address the issue, we propose a novel multi-face tracking method, named ReSORT, that can recover lost identities. Our method removes the cascade matching block in DeepSORT and extends a similarity matching (SM) block after the Kalman filter to assign uncertain tracks to their probable tracking IDs. Such arrangement significantly reduces the processing time while maintaining the longevity of tracking IDs. The SM block functions by storing existing facial features and comparing the similarity between the new and the existing facial features, enabling ReSORT to recover the lost IDs or IDs from other cameras. To benchmark the ID-recovery ability, we introduce three new metrics, calling IDnew, TIDRate, and TReRate. We also produce face tracking annotations for three public surveillance camera datasets, i.e., LAB, MSU-AVIS, and ChokePoint. Extensive experiments conducted on the three datasets with various resolutions and frame-rates settings demonstrate the superiority of ReSORT over DeepSORT, i.e. reducing the identity switches by average 36.38%, and the processing time by 5.19 times. Source code and annotations of all three datasets are available at https://github.com/tantm97/ReSORT.

Abstract We propose a novel approach to developing a tractable affective dialogue model for probabilistic frame-based dialogue systems. The affective dialogue model, based on Partially Observable Markov Decision Process (POMDP) and Dynamic Decision Network (DDN) techniques, is composed of two main parts: the slot-level dialogue manager and the global dialogue manager. It has two new features: (1) being able to deal with a large number of slots and (2) being able to take into account some aspects of the user's affective state in deriving the adaptive dialogue strategies. Our implemented prototype dialogue manager can handle hundreds of slots, where each individual slot might have hundreds of values. Our approach is illustrated through a route navigation example in the crisis management domain. We conducted various experiments to evaluate our approach and to compare it with approximate POMDP techniques and handcrafted policies. The experimental results showed that the DDN–POMDP policy outperforms three handcrafted policies when the user's action error is induced by stress as well as when the observation error increases. Further, performance of the one-step look-ahead DDN–POMDP policy after optimizing its internal reward is close to state-of-the-art approximate POMDP counterparts.