Large-scale fine-grained image retrieval (FGIR) aims to retrieve images belonging to the same subcategory as a given query by capturing subtle differences in a large-scale setting. Recently, Vision Transformers (ViT) have been employed in FGIR due to their powerful self-attention mechanism for modeling long-range dependencies. However, most Transformer-based methods focus primarily on leveraging self-attention to distinguish fine-grained details, while overlooking the high computational complexity and redundant dependencies inherent to these models, limiting their scalability and effectiveness in large-scale FGIR. In this paper, we propose an Efficient and Effective ViT-based framework, termedEET, which integrates token pruning module with a discriminative transfer strategy to address these limitations. Specifically, we introduce a content-based token pruning scheme to enhance the efficiency of the vanilla ViT, progressively removing background or low-discriminative tokens at different stages by exploiting feature responses and self-attention mechanism. To ensure the resulting efficient ViT retains strong discriminative power, we further present a discriminative transfer strategy comprising bothdiscriminative knowledge transferanddiscriminative region guidance. Using a distillation paradigm, these components transfer knowledge from a larger “teacher” ViT to a more efficient “student” model, guiding the latter to focus on subtle yet crucial regions in a cost-free manner. Extensive experiments on two widely-used fine-grained datasets and four large-scale fine-grained datasets demonstrate the effectiveness of our method. Specifically, EET reduces the inference latency of ViT-Small by 42.7% and boosts the retrieval performance of 16-bit hash codes by 5.15% on the challenging NABirds dataset. The code is publicly available at:https://github.com/WhiteJiang/EET.

In hashing-based long-tailed image retrieval, the dominance of data-rich head classes often hinders the learning of effective hash codes for data-poor tail classes due to inherent long-tailed bias. Interestingly, this bias also contains valuable prior knowledge by revealing inter-class dependencies, which can be beneficial for hash learning. However, previous methods have not thoroughly analyzed this tangled negative and positive effects of long-tailed bias from a causal inference perspective. In this paper, we propose a novel hash framework that employs causal inference to disentangle detrimental bias effects from beneficial ones. To capture good bias in long-tailed datasets, we construct hash mediators that conserve valuable prior knowledge from class centers. Furthermore, we propose a de-biased hash loss To enhance the beneficial bias effects while mitigating adverse ones, leading to more discriminative hash codes. Specifically, this loss function leverages the beneficial bias captured by hash mediators to support accurate class label prediction, while mitigating harmful bias by blocking its causal path to the hash codes and refining predictions through backdoor adjustment. Extensive experimental results on four widely used datasets demonstrate that the proposed method improves retrieval performance against the state-of-the-art methods by large margins. The source code is available at https://github.com/IMAG-LuJin/CIH.

This article proposes a new hashing framework named relational consistency induced self-supervised hashing (RCSH) for large-scale image retrieval. To capture the potential semantic structure of data, RCSH explores the relational consistency between data samples in different spaces, which learns reliable data relationships in the latent feature space and then preserves the learned relationships in the Hamming space. The data relationships are uncovered by learning a set of prototypes that group similar data samples in the latent feature space. By uncovering the semantic structure of the data, meaningful data-to-prototype and data-to-data relationships are jointly constructed. The data-to-prototype relationships are captured by constraining the prototype assignments generated from different augmented views of an image to be the same. Meanwhile, these data-to-prototype relationships are preserved to learn informative compact hash codes by matching them with these reliable prototypes. To accomplish this, a novel dual prototype contrastive loss is proposed to maximize the agreement of prototype assignments in the latent feature space and Hamming space. The data-to-data relationships are captured by enforcing the distribution of pairwise similarities in the latent feature space and Hamming space to be consistent, which makes the learned hash codes preserve meaningful similarity relationships. Extensive experimental results on four widely used image retrieval datasets demonstrate that the proposed method significantly outperforms the state-of-the-art methods. Besides, the proposed method achieves promising performance in out-of-domain retrieval tasks, which shows its good generalization ability. The source code and models are available at https://github.com/IMAG-LuJin/RCSH.

Existing unbiased VQA models reduce the spurious correlation between questions and answers to force the models to focus on visual information. However, the visual information captured by these unbiased models is irrelevant to the correct answer, resulting in leveraging spurious correlation to predict incorrect answers. This makes these unbiased methods fail to obtain critical visual information, thus performing poorly on questions dominated by the visual information. To capture the valuable visual information, this paper proposes a novel unbiased VQA model based on causal inference, leveraging Instrumental Variable (IVar) to increase the causal effect between visual features and answers. First, to obtain suitable instrumental variables, the noise generator is proposed according to the constraints of IVar. The generated noise can be regarded as IVar, which is used to pollute the original visual features. Then, this paper proposes IVar loss which utilizes the generated IVar to increase the causal effect between visual features and answers. When the visual feature is polluted by IVar, IVar loss guides the model to predict incorrect answers to enhance the correlation between IVar and the answer. Since the correlation between IVar and the answer is proportional to the causal effect between the visual feature and the answer, IVar loss enhances the importance of the visual information, thereby rectifying the model to capture critical visual information. The extensive experimental results on widely-used benchmarks demonstrate the advantages of the proposed method. The proposed method gains the best accuracy on answer typeOtherof VQA-CP v2. These results demonstrate the superiority of the proposed method in capturing critical visual information since most questions on the answer typeOtherare dominated by visual information.

Compositional action recognition which aims to identify the unseen combinations of actions and objects has recently attracted wide attention. Conventional methods bring in additional cues (e.g., dynamic motions of objects) to alleviate the inductive bias between the visual appearance of objects and the human action-level labels. Besides, compared with non-compositional settings, previous methods only pursue higher performance in compositional settings, which can not prove their generalization ability. To this end, we firstly rethink the problem and design a more generalized metric (namely Drop Ratio) and a more practical setting to evaluate the compositional generalization of existing action recognition algorithms. Beyond that, we propose a simple yet effective framework, Look Less Think More (LLTM), to reduce the strong association between visual objects and action-level labels (Look Less), and then discover the commonsense relationships between object categories and human actions (Think More). We test the rationality of the proposed Drop Ratio and Practical setting by comparing several popular action recognition methods on SSV2. Besides, the proposed LLTM achieves state-of-the-art performance on SSV2 with different settings.

Recently, many Visual Question Answering (VQA) models rely on the correlations between questions and answers yet neglect those between the visual information and the textual information. They would perform badly if the handled data distribute differently from the training data (i.e., out-of-distribution (OOD) data). Towards this end, we propose a two-stage unbiased VQA approach that addresses the unbiased issue from a causal perspective. In the causal inference stage, we mark the spurious correlation on the causal graph, explore the counterfactual causality, and devise a causal target based on the inherent correlations between the conventional and counterfactual VQA models. In the distillation stage, we introduce the causal target into the training process and leverages distilling as well as curriculum learning to capture the unbiased model. Since Causal Inference with Knowledge Distilling and Curriculum Learning (CKCL) reinforces the contribution of the visual information and eliminates the impact of the spurious correlation by distilling the knowledge in causal inference to the VQA model, it contributes to the good performance on both the standard data and out-of-distribution data. The extensive experimental results on VQA-CP v2 dataset demonstrate the superior performance of the proposed method compared to the state-of-the-art (SotA) methods.

With the popularization of social websites, many methods have been proposed to explore the noisy tags for weakly-supervised image hashing.The main challenge lies in learning appropriate and sufficient information from those noisy tags. To address this issue, this work proposes a novel Masked visual-semantic Graph-based Reasoning Network, termed as MGRN, to learn joint visual-semantic representations for image hashing. Specifically, for each image, MGRN constructs a relation graph to capture the interactions among its associated tags and performs reasoning with Graph Attention Networks (GAT). MGRN randomly masks out one tag and then make GAT to predict this masked tag. This forces the GAT model to capture the dependence between the image and its associated tags, which can well address the problem of noisy tags. Thus it can capture key tags and visual structures from images to learn well-aligned visual-semantic representations. Finally, the auto-encoders is leveraged to learn hash codes that can preserve the local structure of the joint space. Meanwhile, the joint visual-semantic representations are reconstructed from those hash codes by using a decoder. Experimental results on two widely-used benchmark datasets demonstrate the superiority of the proposed method for image retrieval compared with several state-of-the-art methods.

Current Visual Question Answering (VQA) models mainly explore the statistical correlations between answers and questions, which fail to capture the relationship between the visual information and answers. The performance dramatically decreases when the distribution of handled data is different from the training data. Towards this end, this paper proposes a novel unbiased VQA model by exploring the Casual Inference with Knowledge Distillation (CIKD) to reduce the influence of bias. Specifically, the causal graph is first constructed to explore the counterfactual causality and infer the casual target based on the causal effect, which well reduces the bias from questions and obtain answers without training. Then knowledge distillation is leveraged to transfer the knowledge of the inferred casual target to the conventional VQA model. It makes the proposed method enable to handle both the biased data and standard data. To address the problem of the bad bias from the knowledge distillation, the ensemble learning is introduced based on the hypothetical bias reason. Experiments are conducted to show the performance of the proposed method. The significant improvements over the state-of-the-art methods on the VQA-CP v2 dataset well validate the contributions of this work.