Cross-modal Retrieval Methods Research Articles

Supervised Contrastive Learning for 3D Cross-Modal Retrieval

Interoperability between different virtual platforms requires the ability to search and transfer digital assets across platforms. Digital assets in virtual platforms are represented in different forms or modalities, such as images, meshes, and point clouds. The cross-modal retrieval of three-dimensional (3D) object representations is challenging due to data representation diversity, making common feature space discovery difficult. Recent studies have been focused on obtaining feature consistency within the same classes and modalities using cross-modal center loss. However, center features are sensitive to hyperparameter variations, making cross-modal center loss susceptible to performance degradation. This paper proposes a new 3D cross-modal retrieval method that uses cross-modal supervised contrastive learning (CSupCon) and the fixed projection head (FPH) strategy. Contrastive learning mitigates the influence of hyperparameters by maximizing feature distinctiveness. The FPH strategy prevents gradient updates in the projection network, enabling the focused training of the backbone networks. The proposed method shows a mean average precision (mAP) increase of 1.17 and 0.14 in 3D cross-modal object retrieval experiments using ModelNet10 and ModelNet40 datasets compared to state-of-the-art (SOTA) methods.

Global-aware Fragment Representation Aggregation Network for image-text retrieval

Image-text retrieval is an important kind of cross-modal retrieval method and has recently attracted much attention. Existing image-text retrieval methods often ignore the relative importance of each fragment (region in an image or word in a sentence) on the global semantic of image or text when aggregating features of image or text fragments, resulting in the ineffectiveness of the learned image and text representations. To address this problem, we propose an image-text retrieval method named Global-aware Fragment Representation Aggregation Network (GFRAN). Specifically, it first designs a fine-grained multimodal information interaction module based on the self-attention mechanism to model both the intra-modality and inter-modality relationships between image regions and words. Then, with the guidance of the global image or text feature, it aggregates image or text fragment features conditioned on their attention weights over global feature, to highlight fragments that contribute more to the overall semantics of images and texts. Extensive experiments on two benchmark datasets Flickr30K and MS-COCO demonstrate the superiority of the proposed GFRAN model over several state-of-the-art baselines.

Semi-supervised Cross-modal Hashing with Joint Hyperboloid Mapping

By using a small amount of label information to achieve favorable performance, semi-supervised methods are more practical in real-world application scenarios. However, existing semi-supervised cross-modal retrieval methods mainly focus on preserving similarities and learning more consistent hash codes yet overlook the importance of constructing a joint abstract space shared by multi-modal embeddings. In this paper, we propose a novel Semi-supervised Cross-modal Hashing with Joint Hyperboloid Mapping (SCH-JHM). Firstly, we present a diffusion-based teacher model in SCH-JHM to learn the generalized semantic knowledge and output the pseudo-labels for unlabeled data. Secondly, SCH-JHM establishes a five-tuple plane, resembling an hourglass, for each retrieval task based on the queries, positive pairs, negative pairs, semi-supervised positive pairs, and semi-supervised negative pairs included in the semi-supervised cross-modal retrieval task. Furthermore, it projects the 12 tasks from the image, text, video, and audio modalities into a joint hyperboloid space. Finally, the student model in SCH-JHM is employed to explore the latent semantic relevance between filtered heterogeneous entities, which can be considered as a supervised process. Comprehensive experiments compared with state-of-the-art methods on three widely used datasets verify the effectiveness of our proposed approach.

Coding self-representative and label-relaxed hashing for cross-modal retrieval

In cross-modal retrieval, most existing hashing-based methods merely considered the relationship between feature representations to reduce the heterogeneous gap for data from various modalities, whereas they neglected the correlation between feature representations and the corresponding labels. This leads to the loss of significant semantic information, and the degradation of the class discriminability of the model. To tackle these issues, this paper presents a novel cross-modal retrieval method called coding self-representative and label-relaxed hashing (CSLRH) for cross-modal retrieval. Specifically, we propose a self-representation learning term to enhance the class-specific feature representations and reduce the noise interference. Additionally, we introduce a label-relaxed regression to establish semantic relations between the hash codes and the label information, aiming to enhance the semantic discriminability. Moreover, we incorporate a non-linear regression to capture the correlation of non-linear features in hash codes for cross-modal retrieval. Experimental results on three widely-used datasets verify the effectiveness of our proposed method, which can generate more discriminative hash codes to improve the precisions of cross-modal retrieval.

Hypergraph clustering based multi-label cross-modal retrieval

Most existing cross-modal retrieval methods face challenges in establishing semantic connections between different modalities due to inherent heterogeneity among them. To establish semantic connections between different modalities and align relevant semantic features across modalities, so as to fully capture important information within the same modality, this paper considers the superiority of hypergraph in representing higher-order relationships, and proposes an image-text retrieval method based on hypergraph clustering. Specifically, we construct hypergraphs to capture feature relationships within image and text modalities, as well as between image and text. This allows us to effectively model complex relationships between features of different modalities and explore the semantic connectivity within and across modalities. To compensate for potential semantic feature loss during the construction of the hypergraph neural network, we design a weight-adaptive coarse and fine-grained feature fusion module for semantic supplementation. Comprehensive experimental results on three common datasets demonstrate the effectiveness of the proposed method.

Semantic Pre-Alignment and Ranking Learning With Unified Framework for Cross-Modal Retrieval

Cross-modal retrieval aims at retrieving highly semantic relevant information among multi-modalities. Existing cross-modal retrieval methods mainly explore the semantic consistency between image and text while rarely consider the rankings of positive instances in the retrieval results. Moreover, these methods seldom take into account the cross-interaction between image and text, which leads to the deficiency of learning their semantic relations. In this paper, we propose a Unified framework with Ranking Learning (URL) for cross-modal retrieval. The unified framework consists of three sub-networks, visual network, textual network, and interaction network. Visual network and textual network project the image feature and text feature into their corresponding hidden spaces respectively. Then, the interaction network forces the target image-text representation to align in the common space. For unifying both semantics and rankings, we propose a new optimization paradigm including pre-alignment for semantic knowledge transfer and ranking learning for final retrieval, which can decouple semantic alignment and ranking learning. The former focuses on the semantic pre-alignment optimized by semantic classification and the latter revolves around the retrieval rankings. For the ranking learning, we introduce a cross-AP loss which can directly optimize the retrieval metric average precision for cross-modal retrieval. We conduct experiments on four widely-used benchmarks, including Wikipedia dataset, Pascal Sentence dataset, NUS-WIDE-10k dataset, and PKU XMediaNet dataset respectively. Extensive experimental results show that the proposed method can obtain higher retrieval precision.

Dual-Pathway Deep Hashing-Based Adversarial Learning for Cross-Modal Retrieval

The application of deep hashing methods for cross-modal retrieval has seen growing interest due to their storage efficiency and fast query execution. However, the challenge posed by the “heterogeneity gap” in multi-modal datasets cannot be understated. To address this, we present a novel framework named Dual-Pathway Deep Hashing-Based Adversarial Learning (DP-DHAL), engineered to surmount this challenge. The architecture of DP-DHAL integrates three key components: (a) a dual-pathway representation learning module tasked with extracting modality-specific features; (b) an adversarial module working to align the distributions of cross-modal features; and (c) a deep hashing module responsible for generating hash codes that uphold the similarity relationships across different modalities. Additionally, we have developed a unique Hamming triplet-margin loss function to refine the assessment of content similarities. The DP-DHAL model is trained through an adversarial process where the adversarial module’s goal is to discern cross-modal features with the aim of reducing the heterogeneity gap. Simultaneously, the representation learning module is focused on producing representations that can both deceive the adversarial module and preserve cross-modal similarities to yield distinctive hash codes. Comprehensive experiments on varied datasets have shown that our proposed method outperforms other leading cross-modal hashing techniques.

Cross-modal retrieval based on multi-dimensional feature fusion hashing

Along with the continuous breakthrough and popularization of information network technology, multi-modal data, including texts, images, videos, and audio, is growing rapidly. We can retrieve different modal data to meet our needs, so cross-modal retrieval has important theoretical significance and application value. In addition, because the data of different modalities can be mutually retrieved by mapping them to a unified Hamming space, hash codes have been extensively used in the cross-modal retrieval field. However, existing cross-modal hashing models generate hash codes based on single-dimension data features, ignoring the semantic correlation between data features in different dimensions. Therefore, an innovative cross-modal retrieval method using Multi-Dimensional Feature Fusion Hashing (MDFFH) is proposed. To better get the image’s multi-dimensional semantic features, a convolutional neural network, and Vision Transformer are combined to construct an image multi-dimensional fusion module. Similarly, we apply the multi-dimensional text fusion module to the text modality to obtain the text’s multi-dimensional semantic features. These two modules can effectively integrate the semantic features of data in different dimensions through feature fusion, making the generated hash code more representative and semantic. Extensive experiments and corresponding analysis results on two datasets indicate that MDFFH’s performance outdoes other baseline models.

Video and audio are images: A cross-modal mixer for original data on video–audio retrieval

Cross-modal retrieval has become popular in recent years, particularly with the rise of multimedia. Generally, the information from each modality exhibits distinct representations and semantic information, which makes feature tends to be in separate latent spaces encoded with dual-tower architecture and makes it challenging to establish semantic relationships between modalities, resulting in poor retrieval performance. To address this issue, we propose a novel framework for cross-modal retrieval consisting of a cross-modal mixer, a masked autoencoder for pre-training, and a cross-modal retriever for downstream tasks. Specifically, we first adopt cross-modal mixer and mask modeling to fuse the original modality and eliminate redundancy. Then, an encoder–decoder architecture is applied to achieve a fuse-then-separate task in the pre-training phase. We feed masked fused representations into the encoder and reconstruct them with the decoder, ultimately separating the original data of two modalities. We use the pre-trained encoder in downstream tasks to build the cross-modal retrieval method. Extensive experiments on 2 real-world datasets show that our approach outperforms previous state-of-the-art methods in video–audio matching tasks, improving retrieval accuracy by up to 2×. Furthermore, we prove our model performance by transferring it to other downstream tasks as a universal model.

Disambiguity and Alignment: An Effective Multi-Modal Alignment Method for Cross-Modal Recipe Retrieval.

As a prominent topic in food computing, cross-modal recipe retrieval has garnered substantial attention. However, the semantic alignment across food images and recipes cannot be further enhanced due to the lack of intra-modal alignment in existing solutions. Additionally, a critical issue named food image ambiguity is overlooked, which disrupts the convergence of models. To these ends, we propose a novel Multi-Modal Alignment Method for Cross-Modal Recipe Retrieval (MMACMR). To consider inter-modal and intra-modal alignment together, this method measures the ambiguous food image similarity under the guidance of their corresponding recipes. Additionally, we enhance recipe semantic representation learning by involving a cross-attention module between ingredients and instructions, which is effective in supporting food image similarity measurement. We conduct experiments on the challenging public dataset Recipe1M; as a result, our method outperforms several state-of-the-art methods in commonly used evaluation criteria.

Improving semantic video retrieval models by training with a relevance-aware online mining strategy

To retrieve a video via a multimedia search engine, a textual query is usually created by the user and then used to perform the search. Recent state-of-the-art cross-modal retrieval methods learn a joint text–video embedding space by using contrastive loss functions, which maximize the similarity of positive pairs while decreasing that of the negative pairs. Although the choice of these pairs is fundamental for the construction of the joint embedding space, the selection procedure is usually driven by the relationships found within the dataset: a positive pair is commonly formed by a video and its own caption, whereas unrelated video-caption pairs represent the negative ones. We hypothesize that this choice results in a retrieval system with limited semantics understanding, as the standard training procedure requires the system to discriminate between groundtruth and negative even though there is no difference in their semantics. Therefore, differently from the previous approaches, in this paper we propose a novel strategy for the selection of both positive and negative pairs which takes into account both the annotations and the semantic contents of the captions. By doing so, the selected negatives do not share semantic concepts with the positive pair anymore, and it is also possible to discover new positives within the dataset. Based on our hypothesis, we provide a novel design of two popular contrastive loss functions, and explore their effectiveness on four heterogeneous state-of-the-art approaches. The extensive experimental analysis conducted on four datasets, EPIC-Kitchens-100, MSR-VTT, MSVD, and Charades, validates the effectiveness of the proposed strategy, observing, e.g., more than +20% nDCG on EPIC-Kitchens-100. Furthermore, these results are corroborated with qualitative evidence both supporting our hypothesis and explaining why the proposed strategy effectively overcomes it.

Deep Neighborhood-aware Proxy Hashing with Uniform Distribution Constraint for Cross-modal Retrieval

Cross-modal retrieval methods based on hashing have gained significant attention in both academic and industrial research. Deep learning techniques have played a crucial role in advancing supervised cross-modal hashing methods, leading to significant practical improvements. Despite these achievements, current deep cross-modal hashing still encounters some underexplored limitations. Specifically, most of the available deep hashing usually utilizes pair-wise or triplet-wise strategies to promote the separation of the inter-classes by calculating the relative similarities between samples, weakening the compactness of intra-class data from different modalities, which could generate ambiguous neighborhoods. In this article, the Deep Neighborhood-aware Proxy Hashing (DNPH) framework is proposed to learn a discriminative embedding space with the original neighborhood relation preserved. By introducing learnable shared category proxies, the neighborhood-aware proxy loss is proposed to project the heterogeneous data into a unified common embedding, in which the sample is pulled closer to the corresponding category proxy and is pushed away from other proxies, capturing small within-class scatter and big between-class scatter. To enhance the quality of the obtained binary codes, the uniform distribution constraint is developed to make each hash bit independently obey the discrete uniform distribution. In addition, the discrimination loss is designed to preserve modality-specific semantic information of samples. Extensive experiments are performed on three benchmark datasets to prove that our proposed DNPH framework achieves comparable or even better performance compared with the state-of-the-art cross-modal retrieval applications. The corresponding code implementation of our DNPH framework is as follows: https://github.com/QinLab-WFU/OUR-DNPH .

Unpaired robust hashing with noisy labels for zero-shot cross-modal retrieval

With new social media concepts emerging, zero-shot cross-modal retrieval methods have gained significant attention. Most of the existing methods assume that the labels of training data are correct and the different modalities are perfectly matched, which is unrealistic in real-life retrieval scenarios. This paper presents a novel approach, termed unpaired robust hashing with noisy labels (URHNL), for zero-shot cross-modal retrieval. Specifically, we developed a zero-shot cross-modal hash retrieval framework that can learn distinct hash codes for different modalities, which is suitable for unpaired cross-modal retrieval scenarios. In addition, it incorporates the sparse constraint on the noise matrix and the low-rank constraint on the recovered label matrix, respectively. These constraints are applied to mitigate the negative effects of noisy labels. Furthermore, we introduce the concept of drag ɛ into the learning process of label semantic embedding, which aims to generate more discriminative hash codes. To improve the similarity of semantic information within hash codes, we consider both intra-modal and inter-modal similarity. A large number of experiments on cross-modal datasets show the effectiveness of the URHNL approach in real and complex zero-shot cross-modal retrieval scenarios. The source code of this word can be found at https://github.com/szq0816/URHNL.

Incomplete Cross-Modal Retrieval with Deep Correlation Transfer

Most cross-modal retrieval methods assume the multi-modal training data is complete and has a one-to-one correspondence. However, in the real world, multi-modal data generally suffers from missing modality information due to the uncertainty of data collection and storage processes, which limits the practical application of existing cross-modal retrieval methods. Although some solutions have been proposed to generate the missing modality data using a single pseudo sample, this may lead to incomplete semantic restoration and sub-optimal retrieval results due to the limited semantic information it provides. To address this challenge, this article proposes an Incomplete Cross-Modal Retrieval with Deep Correlation Transfer (ICMR-DCT) method that can robustly model incomplete multi-modal data and dynamically capture the adjacency semantic correlation for cross-modal retrieval. Specifically, we construct intra-modal graph attention-based auto-encoder to learn modality-invariant representations by performing semantic reconstruction through intra-modality adjacency correlation mining. Then, we design dual cross-modal alignment constraints to project multi-modal representations into a common semantic space, thus bridging the heterogeneous modality gap and enhancing the discriminability of the common representation. We further introduce semantic preservation to enhance adjacency semantic information and achieve cross-modal semantic correlation. Moreover, we propose a nearest-neighbor weighting integration strategy with cross-modal correlation transfer to generate the missing modality data according to inter-modality mapping relations and adjacency correlations between each sample and its neighbors, which improves the robustness of our method against incomplete multi-modal training data. Extensive experiments on three widely tested benchmark datasets demonstrate the superior performance of our method in cross-modal retrieval tasks under both complete and incomplete retrieval scenarios. Our used datasets and source codes are available at https://github.com/shidan0122/DCT.git .

Continual learning for cross-modal image-text retrieval based on domain-selective attention

Cross-modal image-text retrieval (CMITR) has been a high-value research topic for more than a decade. In most of the previous studies, the data for all tasks are trained as a single set. However, in reality, a more likely scenario is that the dataset has multiple tasks and trains them in sequence. The consequence is the limited ability to memorize the old task once a new task arrives; in other words, catastrophic forgetting. To solve this issue, this paper proposes a novel continual learning for cross-modal image-text retrieval (CLCMR) method to alleviate catastrophic forgetting. We construct a multilayer domain-selective attention (MDSA) based network to obtain knowledge from task-relevant and domain-specific attention levels. Moreover, a memory factor has been designed to achieve weight regularization, and a novel memory loss function is utilized to constrain MDSA. The extensive experimental results from multiple datasets (Wikipedia, Pascal Sentence, and PKU XMedianet datasets) demonstrate that CLCMR can effectively alleviate catastrophic forgetting and achieve a superior continual learning ability compared with the state-of-the-art methods.

Cross-Modal Retrieval and Semantic Refinement for Remote Sensing Image Captioning

Two-stage remote sensing image captioning (RSIC) methods have achieved promising results by incorporating additional pre-trained remote sensing tasks to extract supplementary information and improve caption quality. However, these methods face limitations in semantic comprehension, as pre-trained detectors/classifiers are constrained by predefined labels, leading to an oversight of the intricate and diverse details present in remote sensing images (RSIs). Additionally, the handling of auxiliary remote sensing tasks separately can introduce challenges in ensuring seamless integration and alignment with the captioning process. To address these problems, we propose a novel cross-modal retrieval and semantic refinement (CRSR) RSIC method. Specifically, we employ a cross-modal retrieval model to retrieve relevant sentences of each image. The words in these retrieved sentences are then considered as primary semantic information, providing valuable supplementary information for the captioning process. To further enhance the quality of the captions, we introduce a semantic refinement module that refines the primary semantic information, which helps to filter out misleading information and emphasize visually salient semantic information. A Transformer Mapper network is introduced to expand the representation of image features beyond the retrieved supplementary information with learnable queries. Both the refined semantic tokens and visual features are integrated and fed into a cross-modal decoder for caption generation. Through extensive experiments, we demonstrate the superiority of our CRSR method over existing state-of-the-art approaches on the RSICD, the UCM-Captions, and the Sydney-Captions datasets

Cross-Modal Retrieval With Noisy Correspondence via Consistency Refining and Mining.

The success of existing cross-modal retrieval (CMR) methods heavily rely on the assumption that the annotated cross-modal correspondence is faultless. In practice, however, the correspondence of some pairs would be inevitably contaminated during data collection or annotation, thus leading to the so-called Noisy Correspondence (NC) problem. To alleviate the influence of NC, we propose a novel method termed Consistency REfining And Mining (CREAM) by revealing and exploiting the difference between correspondence and consistency. Specifically, the correspondence and the consistency only be coincident for true positive and true negative pairs, while being distinct for false positive and false negative pairs. Based on the observation, CREAM employs a collaborative learning paradigm to detect and rectify the correspondence of positives, and a negative mining approach to explore and utilize the consistency. Thanks to the consistency refining and mining strategy of CREAM, the overfitting on the false positives could be prevented and the consistency rooted in the false negatives could be exploited, thus leading to a robust CMR method. Extensive experiments verify the effectiveness of our method on three image-text benchmarks including Flickr30K, MS-COCO, and Conceptual Captions. Furthermore, we adopt our method into the graph matching task and the results demonstrate the robustness of our method against fine-grained NC problem. The code is available on https://github.com/XLearning-SCU/2024-TIP-CREAM.

Geometric Matching for Cross-Modal Retrieval.

Despite its significant progress, cross-modal retrieval still suffers from one-to-many matching cases, where the multiplicity of semantic instances in another modality could be acquired by a given query. However, existing approaches usually map heterogeneous data into the learned space as deterministic point vectors. In spite of their remarkable performance in matching the most similar instance, such deterministic point embedding suffers from the insufficient representation of rich semantics in one-to-many correspondence. To address the limitations, we intuitively extend a deterministic point into a closed geometry and develop geometric representation learning methods for cross-modal retrieval. Thus, a set of points inside such a geometry could be semantically related to many candidates, and we could effectively capture the semantic uncertainty. We then introduce two types of geometric matching for one-to-many correspondence, i.e., point-to-rectangle matching (dubbed P2RM) and rectangle-to-rectangle matching (termed R2RM). The former treats all retrieved candidates as rectangles with zero volume (equivalent to points) and the query as a box, while the latter encodes all heterogeneous data into rectangles. Therefore, we could evaluate semantic similarity among heterogeneous data by the Euclidean distance from a point to a rectangle or the volume of intersection between two rectangles. Additionally, both strategies could be easily employed for off-the-self approaches and further improve the retrieval performance of baselines. Under various evaluation metrics, extensive experiments and ablation studies on several commonly used datasets, two for image-text matching and two for video-text retrieval, demonstrate our effectiveness and superiority.

Unsupervised Dual Deep Hashing with Semantic-Index and Content-Code for Cross-Modal Retrieval.

Hashing technology has exhibited great cross-modal retrieval potential due to its appealing retrieval efficiency and storage effectiveness. Most current supervised cross-modal retrieval methods heavily rely on accurate semantic supervision, which is intractable for annotations with ever-growing sample sizes. By comparison, the existing unsupervised methods rely on accurate sample similarity preservation strategies with intensive computational costs to compensate for the lack of semantic guidance, which causes these methods to lose the power to bridge the semantic gap. Furthermore, both kinds of approaches need to search for the nearest samples among all samples in a large search space, whose process is laborious. To address these issues, this paper proposes an unsupervised dual deep hashing (UDDH) method with semantic-index and content-code for cross-modal retrieval. Deep hashing networks are utilized to extract deep features and jointly encode the dual hashing codes in a collaborative manner with a common semantic index and modality content codes to simultaneously bridge the semantic and heterogeneous gaps for cross-modal retrieval. The dual deep hashing architecture, comprising the head code on semantic index and tail codes on modality content, enhances the efficiency for cross-modal retrieval. A query sample only needs to search for the retrieved samples with the same semantic index, thus greatly shrinking the search space and achieving superior retrieval efficiency. UDDH integrates the learning processes of deep feature extraction, binary optimization, common semantic index, and modality content code within a unified model, allowing for collaborative optimization to enhance the overall performance. Extensive experiments are conducted to demonstrate the retrieval superiority of the proposed approach over the state-of-the-art baselines.

Keyword-Based Diverse Image Retrieval With Variational Multiple Instance Graph.

The task of cross-modal image retrieval has recently attracted considerable research attention. In real-world scenarios, keyword-based queries issued by users are usually short and have broad semantics. Therefore, semantic diversity is as important as retrieval accuracy in such user-oriented services, which improves user experience. However, most typical cross-modal image retrieval methods based on single point query embedding inevitably result in low semantic diversity, while existing diverse retrieval approaches frequently lead to low accuracy due to a lack of cross-modal understanding. To address this challenge, we introduce an end-to-end solution termed variational multiple instance graph (VMIG), in which a continuous semantic space is learned to capture diverse query semantics, and the retrieval task is formulated as a multiple instance learning problems to connect diverse features across modalities. Specifically, a query-guided variational autoencoder is employed to model the continuous semantic space instead of learning a single-point embedding. Afterward, multiple instances of the image and query are obtained by sampling in the continuous semantic space and applying multihead attention, respectively. Thereafter, an instance graph is constructed to remove noisy instances and align cross-modal semantics. Finally, heterogeneous modalities are robustly fused under multiple losses. Extensive experiments on two real-world datasets have well verified the effectiveness of our proposed solution in both retrieval accuracy and semantic diversity.