Facial Expression Recognition (FER) seeks to classify affective states from facial images, which remains a challenging problem due to variations in real-world conditions. FER task becomes particularly complex when handling unconstrained environments characterized by partial occlusions, different head poses, and so on. To address the above problems, current approaches rely on extensive learnable parameters and complex model architectures, which inevitably lead to overfitting and cause the FER model to focus on non-discriminative facial regions. In this work, we propose an HKAFER model that can adaptively enhance visual expression representations through efficiently fine-tuning the image encoder in large Visual Foundation Models (VFMs) and Vision-Language Models (VLMs). Specifically, we establish Heterogeneous Kronecker Adaptation (HeKA), which consists of multi-scale adapters based on Kronecker product in a parallel manner, offering significantly diverse subspaces to learn the incremental matrices. Besides, we also propose Dual-Branch Interactive Router (DBIR) to dynamically assign the weights of adapters, which promotes collaboration and information flow among them. In this way, our HKAFER can effectively capture robust spatial features and the regional associations. Experimental results demonstrate that our proposed model not only outperforms state-of-the-art methods on several FER benchmarks but also uses significantly fewer trainable parameters.

Emotion Recognition in Conversation (ERC) plays an important role in driving the development of human-machine interaction. After the extensive exploration of the text modality, visual and audio information has attracted considerable attention. Most of the existing approaches adopt either the attention mechanism or graph neural networks to conduct multi-modal fusion by directly utilizing pre-extracted single modal features, but they ignore the inherent priors and characteristics (highly related to emotions) contained in different modalities. For example, for visual modality, facial expression can well reveal a person's emotional state, and the intonation, speech rate and volume of audio modality also reflect emotional fluctuation. Thus, in this work, we aim to promote context fusion among multi-modal features by exploring inherent modal priors. Firstly, we create textual descriptions for different emotion categories belonging to different modalities, denoted as multimodal prompts which can be generated either from common sense or using large language models (e.g., ChatGPT). Then, we propose an adaptive gating fusion module which dynamically learns the weights between unimodal features and prompts, and allows the multimodal prompts to participate in encoding and enriching modal information. Finally, to facilitate multimodal fusion, we design a multimodal progressive encoder to learn inter-modal interactions among conversational utterances. Experimental results show that our model outperforms state-of-the-art models in ERC on two popular benchmark datasets.

Facial Expression Recognition (FER) aims to categorize emotional expressions depicted on a human face, and is a challenging task under unconstrained conditions, such as face occlusions and pose variations. Recent methods usually adopt self attention or cross attention to explore global or local relationships among different level features. However, these methods are inclined to focus on the redundant facial regions, causing model overfitting. To address this problem, we propose a new FER model named JADFER, which drops the joint attention in the weight matrix to adaptively enhance facial expression representations. Specifically, our JADFER model consists of three components: Spatial Branch (SB), Contextual Branch (CB), and Spatial-Contextual Interaction (SCI). First, SB runs$N$paths in parallel, where a Variety loss is designed to guide the paths of SB to focus on different discriminative regions. Meanwhile, CB abstracts the contextual facial representations using self attention with Joint Attention Dropping (JAD). Then, the SCI adopts the spatial features from SB to query the contextual representations from CB through cross attention with JAD, which regulates the attention weights by dropping the similar activations to further enhance the facial embeddings. Experimental results demonstrate that the proposed model outperforms the state-of-the-art methods on several FER benchmarks.

In the fields of health care and clinical monitoring, vision-based Facial Expression Recognition (FER) has achieved significantly progress, but it still faces the challenge of poor generalization ability under unconstrained conditions of occlusions and pose variation. Recently, Vision-Language Model (VLM) has greatly advanced the FER task. However, the existing VLM-based FER methods typically leverage a hard-crafted prompt (e.g., “a photo of [class]”) and only focus on the holistic semantic alignment, which may suffer from modal heterogeneity. In this work, we propose a fine-grained vision-language model via Prompt Masking for FER (PMFER). Specifically, for each expression, we first create fine-grained prompts using facial action units to guide the image encoder to learn discriminative representations. Further, to finely align text prompts and visual action units, we randomly drop a phrase description in the prompts and then predict the dropped phrase by conducting modal cross attention, implicitly promoting fine-grained vision-language alignment. In addition, we also design a modal-adversarial strategy to holistically eliminate the modal difference between visual and textual embeddings in a common latent space. Experimental results demonstrate that our PMFER model outperforms the state-of-the-art methods on several FER benchmarks, especially under the conditions of occlusions and pose variations. Note to Practitioners—Facial expression recognition is very important in health care and clinical monitoring, which provides an useful tool to assess the psychological and physiological conditions of patients. Although FER has made significant progress with the development of deep learning technologies, it still faces problems in the complex environments (e.g., occlusions and pose variations). To address the above issues, we propose a novel FER method in this work based on the recent vision-language model. It takes RGB image and text prompts as input and finally predicts the expression classification. Different from the existing methods, the proposed PMFER can enable fine-grained modal alignment for facial key units. Compared with the state-of-the-art methods on the public datasets, it can achieve better results, especially under the conditions of occlusions and pose variations. Also, we evaluate the proposed method on a real-world pain dataset, and the results demonstrate that PMFER has a good generalization and can be applied to health care.

In the field of robotics, vision-based Emotion Recognition (ER) has achieved significant progress, but it still faces the challenge of poor generalization ability under unconstrained conditions (e.g., occlusions and pose variations). In this work, we propose MLPER model, which introduces Vision-Language Model for Emotion Recognition to learn discriminative representations adaptively. Specifically, different from typically leveraging a hand-crafted prompt (e.g., "a photo of a [class] person"), we first establish Multi-Level Prompts from three aspects: facial expression, human posture and situational condition using large language models, like ChatGPT. Correspondingly, we extract the visual tokens from three levels: the face, body, and context. Further, to achieve fine-grained alignment at each level, we adopt textual tokens from the positive and the hard negative to query visual tokens, predicting whether a pair of image and text is matched. Experimental results demonstrate that our MLPER model outperforms the state-of-the-art methods on several ER benchmarks, especially under the conditions of occlusions and pose variations.

The main challenge of Multi-Object Tracking (MOT) lies in maintaining a distinctive identity for each target in dense crowds or occluded scenarios. Although the existing methods have achieved significantly progress by using robust object detectors or complex association strategies, they cannot effectively solve long-term tracking due to individually motion or appearance modeling for each single target. In this paper, we propose a novel 2D MOT tracker GroupTrack, to learn reliable motion state for each target using group motion patterns. Specifically, for each tracklet, we first choose its neighboring ones to form a group of motion patterns, which can provide informative clues for the motion estimation of the current tracklet. Then, we apply the group motion patterns to perform tracklet prediction and data association. By integrating prior from neighboring motion patterns into the data association process, GroupTrack provides a new paradigm for target motion modeling in extremely crowded and occluded scenarios. Through extensive experiments on the public MOT17 and MOT20 datasets, we demonstrate the effectiveness of our approach in challenging scenarios and show state-of-the-art performance at various MOT metrics.

Facial Expression Recognition (FER) aims to identify emotional expressions in human faces, and it is a fundamental task in computer vision. Recently, some methods apply Vision Transformer (ViT) to FER and have achieved promising results. However, FER still suffers from two key issues: inter-class similarity and intra-class discrepancy. To address the issues, in this letter, we propose a Multi-Scale Attention Learning Network (MALN) based on ViT, which can learn facial expression embeddings in a multi-scale manner. Specifically, we adopt a multi-branch ViT architecture to adaptively explore multi-scale correlations without self-attention. Furthermore, we also design a Scale Distinction Loss (SDL) to dynamically regulate facial embeddings from multiple branches, which can guide ViT to capture discriminative facial regions. Experimental results on three public datasets (inluding RAF-DB, AffectNet and FERPlus) demonstrate the effectiveness of our proposed MALN for FER