Graph based methods have been widely used in incomplete multi-view clustering (IMVC). Most recent methods try to fill the original missing samples or incomplete affinity matrices to obtain a complete similarity graph for the subsequent spectral clustering. However, recovering the original high-dimensional data or complete n X n similarity matrix is usually time-consuming and noise-sensitive. Besides, they generally separate the cluster indicator learning into an individual step, which may result in sub-optimal graphs or spectral embeddings for clustering. To address these problems, this paper proposes a robust Spectral Embedding Completion based IMVC (SEC-IMVC) method, which incorporates spectral embedding completion and discrete cluster indicator learning into a unified framework. SEC-IMVC performs completion on spectral embeddings, and the embedding noise is eliminated to reduce the negative influence of original data noise. The discrete cluster indicator matrix is seamlessly learned by using spectral rotation, and it can explore the first-order feature consistency among different views. To further improve the completion robustness, the second-order correlation consistency is also captured by pairwise relations alignment. We compare our method with some state-of-the-art approaches on several datasets, and the experimental results show the effectiveness and advantages of our method.
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Domain generalization (DG) refers to the task of training a model on multiple source domains and test it on a different target domain with different distribution. In this paper, we address a more challenging and realistic scenario known as Single Long-Tailed Domain Generalization, where only one source domain is available and the minority class in this domain has an abundance of instances in other domains. To tackle this task, we propose a novel approach called Mixture-of-Experts Learner for Single Long-Tailed Domain Generalization (MoEL), which comprises two key strategies. The first strategy is a simple yet effective data augmentation technique that leverages saliency maps to identify important regions on the original images and preserves these regions during augmentation. The second strategy is a new skill-diverse expert learning approach that trains multiple experts from a single long-tailed source domain and leverages mutual learning to aggregate their learned knowledge for the unknown target domain. We evaluate our method on various benchmark datasets, including Digits-DG, CIFAR-10-C, PACS, and DomainNet, and demonstrate its superior performance compared to previous single domain generalization methods. Additionally, the ablation study is also conducted to illustrate the inner workings of our approach.
The task of domain generalization is to learn a classification model from multiple source domains and generalize it to unknown target domains. The key to domain generalization is learning discriminative domain-invariant features. Invariant representations are achieved using adversarial domain generalization as one of the primary techniques. For example, generative adversarial networks have been widely used, but suffer from the problem of low intra-class diversity, which can lead to poor generalization ability. To address this issue, we propose a new method called auxiliary classifier in adversarial domain generalization (CloCls). CloCls improve the diversity of the source domain by introducing auxiliary classifier. Combining typical task-related losses, e.g., cross-entropy loss for classification and adversarial loss for domain discrimination, our overall goal is to guarantee the learning of condition-invariant features for all source domains while increasing the diversity of source domains. Further, inspired by smoothing optima have improved generalization for supervised learning tasks like classification. We leverage that converging to a smooth minima with respect task loss stabilizes the adversarial training leading to better performance on unseen target domain which can effectively enhances the performance of domain adversarial methods. We have conducted extensive image classification experiments on benchmark datasets in domain generalization, and our model exhibits sufficient generalization ability and outperforms state-of-the-art DG methods.
Face recognition has made significant advances with the development of deep learning and has begun to be deployed in some unrestricted scenarios. Many smartphones, for example, have infrared sensors that allow them to capture clear images even in low-light conditions. Face authentication under complex environmental conditions can thus be accomplished by matching NIR-VIS face images across modalities. However, existing NIR-VIS datasets lack enough variation in face attributes and are insufficient for real-world scenarios. To address the aforementioned issues, we first propose a 300-person NIR-VIS cross-modality face dataset with a variety of attributes. Based on modal information removal, we proposed a NIR-VIS cross-modal face recognition model. We can effectively extract modal information by constraining the similarity distribution of modalities and then using the orthogonal loss to remove modal information from identity features. The method achieves excellent results on our dataset and CASIA NIR-VIS 2.0 dataset.
Audio and vision are important senses for high-level cognition, and their special strong correlation makes audio-visual coding a crucial factor in many multimodal tasks. However, there are two challenges in audio-visual coding. First, the heterogeneity of multimodal data often leads to misalignment of cross-modal features under the same sample, which reduces their representation quality. Second, most self-supervised learning frameworks are constructed based on instance semantics, and the generated pseudo labels introduce additional classification noise. To address these challenges, we propose a Supervised Cross-modal Contrastive Learning Framework for Audio-Visual Coding (SCLAV). Our framework includes an audio-visual coding network composed of an inter-modal attention interaction module and an intra-modal self-integration module, which leverage multimodal complementary and hidden information for better representation. Additionally, we introduce a supervised cross-modal contrastive loss to minimize the distance between audio and vision features of the same instance, and use weak labels of multimodal data to eliminate the feature-oriented classification noise. Extensive experiments on the AVE and XD-Violence datasets demonstrate that SCLAV outperforms the state-of-the-art results, even with limited computational resources.
Blind image deblurring remains challenging due to the ill-posed nature of the traditional blurring function. Although previous supervised methods have achieved great breakthrough with synthetic blurry-sharp image pairs, their generalization ability to real-world blurs is limited by the discrepancy between synthetic and real blurs. To overcome this limitation, unsupervised deblurring methods have been proposed by using natural priors or generative adversarial networks. However, natural priors are vulnerable to random blur artifacts, while generators of generative adversarial networks always produce inaccurate details and unrealistic colors. Consequently, previous methods easily suffer from slow convergence and poor performance. In this work, we propose to formulate the traditional blurring function as the composition of multiple variates, thus allowing us explicitly define characteristics of residual images between blurry and sharp images. We also propose a multi-step self-supervised deblurring framework to address the slow convergence issue. Our framework continuously decomposes and composes input images, thus utilizing the uncertainty of blur artifacts to obtain diverse pseudo blurry-sharp image pairs for self-supervised learning. This framework is more efficient than previous methods, as it does not rely on natural priors or GANs. Extensive comparisons demonstrate that the proposed framework outperforms state-of-the-art unsupervised methods on both dynamic scene, human-aware centric motion, real-world and out-of-focus deblurring datasets. The codes are available at https://github.com/ddghjikle/MM-2023-USDF.
Hyperspectral images (HSIs) offer great potential for computational pathology. However, limited by the spectral redundancy and the lack of spectral prior in popular 2D networks, previous HSI based techniques do not perform well. To address these problems, we propose to segment HSIs from a deformable perspective, which processes different spectral bands independently and fuses spatiospectral features of interest via deformable attention mechanisms. In addition, we propose Deformable Self-Supervised Spectral Regression (DF-S3R), which introduces two self-supervised pre-text tasks based on the low rank prior of HSIs enabling the network learning with spectrum-related features. During pre-training, DF-S3R learns both spectral structures and spatial morphology, and the jointly pre-trained architectures help alleviate the transfer risk to downstream fine-tuning. Compared to previous works, experiments show that our deformable architecture and pre-training method perform much better than other competitive methods on pathological semantic segmentation tasks, and the visualizations indicate that our method can trace the critical spectral characteristics from subtle spectral disparities. Code will be released at https://github.com/Ayakax/DFS3R.
Painterly image harmonization aims to insert photographic objects into paintings and obtain artistically coherent composite images. Previous methods for this task mainly rely on inference optimization or generative adversarial network, but they are either very time-consuming or struggling at fine control of the foreground objects (e.g., texture and content details). To address these issues, we propose a novel Painterly Harmonization stable Diffusion model (PHDiffusion), which includes a lightweight adaptive encoder and a Dual Encoder Fusion (DEF) module. Specifically, the adaptive encoder and the DEF module first stylize foreground features within each encoder. Then, the stylized foreground features from both encoders are combined to guide the harmonization process. During training, besides the noise loss in diffusion model, we additionally employ content loss and two style losses, i.e., AdaIN style loss and contrastive style loss, aiming to balance the trade-off between style migration and content preservation. Compared with the state-of-the-art models from related fields, our PHDiffusion can stylize the foreground more sufficiently and simultaneously retain finer content. Our code and model are available at https://github.com/bcmi/PHDiffusion-Painterly-Image-Harmonization
Federated learning provides a privacy-preserving manner to collaboratively train models on data distributed over multiple local clients via the coordination of a global server. In this paper, we focus on label distribution skew in federated learning, where due to the different user behavior of the client, label distributions between different clients are significantly different. When faced with such cases, most existing methods will lead to a suboptimal optimization due to the inadequate utilization of label distribution information in clients. Inspired by this, we propose a label-masking distillation approach termed FedLMD to facilitate federated learning via perceiving the various label distributions of each client. We classify the labels into majority and minority labels based on the number of examples per class during training. The client model learns the knowledge of majority labels from local data. The process of distillation masks out the predictions of majority labels from the global model, so that it can focus more on preserving the minority label knowledge of the client. A series of experiments show that the proposed approach can achieve state-of-the-art performance in various cases. Moreover, considering the limited resources of the clients, we propose a variant FedLMD-Tf that does not require an additional teacher, which outperforms previous lightweight approaches without increasing computational costs. Our code is available at https://github.com/wnma3mz/FedLMD.
Air Traffic Control (ATC) is a complicated, time-evolving, and real-time procedure to direct flight operations in a safer and ordered manner. Although enormous data storages are available during air traffic operations for over 40 years, data-driven intelligent application in aviation is still an emerging task due to the safety-critical issue. With the prevalence of the Next Generation ATC system, artificial intelligence (AI) -empowered research topics are attracting increasing attention from both industrial and academic domains and a high-quality dataset naturally becomes the prerequisite for such practices. However, almost all ATC-related datasets are only unimodal for certain tasks, which fails to comprehensively illustrate the traffic situation to further support real-world studies. To address this gap, a multimodal air traffic situation (M2ATS) dataset is constructed to advance AI-related research in the ATC domain, including airspace information, flight plan, trajectory, and speech. M2ATS covers 10362 flights ATC situation data, involving 110000+ utterances (104 hours) with diversity golden text annotations, 16 intents, and 51 slots. Considering the real-world ATC requirements, a total of 10 multimedia-related tasks (24 baselines) are designed to validate the proposed dataset, covering automatic speech recognition, natural language processing, and spatial-temporal data processing. New ATC-related metrics corresponding to ATC applications are proposed in addition to the common metrics to evaluate task performance. Extensive experiment results demonstrate that the selective baselines can achieve designed tasks on this new dataset, and further investigations are also required to address task and data specificities. It is believed that the proposed new dataset is a new practice to advance AI applications to an industrial scene, which not only promotes ATC-related applications but also provides diverse research topics in the common multimedia community.
Video anomaly detection is an essential yet challenging task in the multimedia community, with promising applications in smart cities and secure communities. Existing methods attempt to learn abstract representations of regular events with statistical dependence to model the endogenous normality, which discriminates anomalies by measuring the deviations to the learned distribution. However, conventional representation learning is only a crude description of video normality and lacks an exploration of its underlying causality. The learned statistical dependence is unreliable for diverse regular events in the real world and may cause high false alarms due to over generalization. Inspired by causal representation learning, we think that there exists a causal variable capable of adequately representing the general patterns of regular events in which anomalies will present significant variations. Therefore, we design a causality-inspired representation consistency (CRC) framework to implicitly learn the unobservable causal variables of normality directly from available normal videos and detect abnormal events with the learned representation consistency. Extensive experiments show that the causality-inspired normality is robust to regular events with label-independent shifts, and the proposed CRC framework can quickly and accurately detect various complicated anomalies from real-world surveillance videos.
Recognizing activities with Unmanned Aerial Vehicles (UAVs) is essential for many applications, while existing video recognition methods are mainly designed for ground cameras and do not account for UAV changing attitudes and fast motion. This creates spatial misalignment of small objects between frames, leading to inaccurate visual movement in drone videos. Additionally, camera motion relative to objects in the video causes relative movements that visually affect object motion and can result in misunderstandings of video content. To address these issues, we present a novel framework named Attentional Spatial and Adaptive Temporal Relations Modeling. First, to mitigate the spatial misalignment of small objects between frames, we design an Attentional Patch-level Spatial Enrichment (APSE) module that models dependencies among patches and enhances patch-level features. Then, we propose a Multi-scale Temporal and Spatial Mixer (MTSM) module that is capable of adapting to disturbances caused by the UAV flight and modeling various temporal clues. By integrating APSE and MTSM into a single model, our network can effectively and accurately capture spatiotemporal relations for UAV videos. Extensive experiments on several benchmarks demonstrate the superiority of our method over state-of-the-art approaches. For instance, our network achieves a classification accuracy of 68.1% with an absolute gain of 1.3% compared to FuTH-Net on the ERA dataset.
Voice conversion as the style transfer task applied to speech, refers to converting one person's speech into a new speech that sounds like another person's. Up to now, there has been a lot of research devoted to better implementation of VC tasks. However, a good voice conversion model should not only match the timbre information of the target speaker, but also expressive information such as prosody, pace, pause, etc. In this context, prosody modeling is crucial for achieving expressive voice conversion that sounds natural and convincing. Unfortunately, prosody modeling is important but challenging, especially without text transcriptions. In this paper, we firstly propose a novel voice conversion framework named 'PMVC', which effectively separates and models the content, timbre, and prosodic information from the speech without text transcriptions. Specially, we introduce a new speech augmentation algorithm for robust prosody extraction. And building upon this, mask and predict mechanism is applied in the disentanglement of prosody and content information. The experimental results on the AIShell-3 corpus supports our improvement of naturalness and similarity of converted speech.
Recent adaptive methods for efficient video recognition mostly follow the two-stage paradigm of "preview-then-recognition" and have achieved great success on multiple video benchmarks. However, this two-stage paradigm involves two visits of raw frames from coarse-grained to fine-grained during inference (cannot be parallelized), and the captured spatiotemporal features cannot be reused in the second stage (due to varying granularity), being not friendly to efficiency and computation optimization.To this end, inspired by human cognition, we propose a novel recognition paradigm of "View while Moving" for efficient long-untrimmed video recognition.In contrast to the two-stage paradigm, our paradigm only needs to access the raw frame once.The two phases of coarse-grained sampling and fine-grained recognition are combined into unified spatiotemporal modeling, showing great performance.Moreover, we investigate the properties of semantic units in video and propose a hierarchical mechanism to efficiently capture and reason about the unit-level and video-level temporal semantics in long-untrimmed videos respectively.Extensive experiments on both long-untrimmed and short-trimmed videos demonstrate that our approach outperforms state-of-the-art methods in terms of accuracy as well as efficiency, yielding new efficiency and accuracy trade-offs for video spatiotemporal modeling.
Unsupervised Domain Adaptive Nighttime Semantic Segmentation (UDA-NSS) aims to adapt a robust model from a labeled daytime domain to an unlabeled nighttime domain. However, current advanced segmentation methods ignore the illumination effect and class discrepancies of different semantic classes during domain adaptation, showing an uneven prediction phenomenon. It is the completely ignored and underexplored issues of ''hard-to-adapt'' classes that some classes have a large performance gap between existing UDA-NSS methods and supervised learning counterparts while others have a very low performance gap. To realize ''hard-to-adapt'' classes' more sufficient learning and facilitate the UDA-NSS task, we present an Online Informative Class Sampling (OICS) strategy to adaptively mine informative classes from the target nighttime domain according to the corresponding spectrogram mean and the class frequency via our Informative Mixture of Experts. Furthermore, an Informativeness-based cross-domain Mixed Sampling (InforMS) framework is designed to focus on informative classes from the target nighttime domain by vesting their higher sampling probabilities when cross-domain mixing sampling and achieves better performance in UDA-NSS tasks. Consequently, our method outperforms state-of-the-art UDA-NSS methods by large margins on three widely-used benchmarks (e.g., ACDC, Dark Zurich, and Nighttime Driving). Notably, our method achieves state-of-the-art performance with 65.1% mIoU on ACDC-night-test and 55.4% mIoU on ACDC-night-val.
Incremental object detection (IOD) aims to mitigate catastrophic forgetting for object detectors when incrementally learning to detect new emerging object classes without using original training data. Most existing IOD methods benefit from the assumption that unlabeled old-class objects may co-occur with labeled new-class objects in the new training data. However, in practical scenarios, old-class objects may be absent, which is called non co-occurrence IOD. In this paper, we propose a pseudo object replay and mining method (PseudoRM) to handle the co-occurrence dependent problem, reducing the performance degradation caused by the absence of old-class objects. The new training data can be augmented by co-occurring fake (old-class) and real (new-class) objects with a patch-level data-free generation method in the pseudo object replay stage. To fully use existing training data, we propose pseudo object mining to explore false positives for transferring useful instance-level knowledge. In the incremental learning procedure, a generative distillation is introduced to distill image-level knowledge for balancing stability and plasticity. Experimental results on PASCAL VOC and COCO demonstrate that PseudoRM can effectively boost the performance on both co-occurrence and non co-occurrence scenarios without using old samples or extra wild data.
The self-media era provides us tremendous high quality videos. Unfortunately, frequent video copyright infringements are now seriously damaging the interests and enthusiasm of video creators. Identifying infringing videos is therefore a compelling task. Current state-of-the-art methods tend to simply feed high-dimensional mixed video features into deep neural networks and count on the networks to extract useful representations. Despite its simplicity, this paradigm heavily relies on the original entangled features and lacks constraints guaranteeing that useful task-relevant semantics are extracted from the features. In this paper, we seek to tackle the above challenges from two aspects: (1) We propose to disentangle an original high-dimensional feature into multiple sub-features, explicitly disentangling the feature into exclusive lower-dimensional components. We expect the sub-features to encode non-overlapping semantics of the original feature and remove redundant information. (2) On top of the disentangled sub-features, we further learn an auxiliary feature to enhance the sub-features. We theoretically analyzed the mutual information between the label and the disentangled features, arriving at a loss that maximizes the extraction of task-relevant information from the original feature. Extensive experiments on two large-scale benchmark datasets (i.e., SVD and VCSL) demonstrate that our method achieves 90.1% TOP-100 mAP on the large-scale SVD dataset and also sets the new state-of-the-art on the VCSL benchmark dataset. Our code and model have been released at https://github.com/yyyooooo/DMI/, hoping to contribute to the community.
Temporal action detection (TAD) aims to localize the start and end frames of actions in untrimmed videos, which is a challenging task due to the similarity of adjacent frames and the ambiguity of action boundaries. Previous methods often generate coarse proposals first and then perform proposal-based refinement, which is coupled with prior action detectors and leads to proposal-oriented offsets. However, this paradigm increases the training difficulty of the TAD model and is heavily influenced by the quantity and quality of the proposals. To address the above issues, we decouple the refinement process from conventional TAD methods and propose a learnable, proposal-free refinement method for fine boundary localization, named RefineTAD. We first propose a multi-level refinement module to generate multi-scale boundary offsets, score offsets and boundary-aware probability at each time point based on the feature pyramid. Then, we propose an offset focusing strategy to progressively refine the predicted results of TAD models in a coarse-to-fine manner with our multi-scale offsets. We perform extensive experiments on three challenging datasets and demonstrate that our RefineTAD significantly improves the state-of-the-art TAD methods with minimal computational overhead.
In this paper, we propose a new multi-scale similarity aggregation method (MSA) for dynamic metric learning (DyML), which adopts a pretraining-finetuning scheme and efficiently learns the similarity relationship for each semantic level. In particular, building upon the framework of self-supervised pretraining, the output embedding layer is divided into three learners to learn the similarity relations in each level individually. Then for training these learners, the hierarchical prior information is fully considered. Specifically, in light of the class hierarchy that each class in a coarse level corresponds to a set of subclasses in a finer level, multi-proxy learning is employed to facilitate the single-level similarity learning of each learner. On the other hand, following the hierarchical consistency property, a cross-level similarity constraint is further presented to encourage the estimated similarities of the three learners to be hierarchically consistent. Extensive experiments on three DyML datasets show that MSA significantly outperforms the existing state-of-the-art methods and allows for a better generalization for different semantic scales.
Binary silhouettes and keypoint-based skeletons have dominated human gait recognition studies for decades since they are easy to extract from video frames. Despite their success in gait recognition for in-the-lab environments, they usually fail in real-world scenarios due to their low information entropy for gait representations. To achieve accurate gait recognition in the wild, this paper presents a novel gait representation, named Gait Parsing Sequence (GPS). GPSs are sequences of fine-grained human segmentation, i.e., human parsing, extracted from video frames, so they have much higher information entropy to encode the shapes and dynamics of fine-grained human parts during walking. Moreover, to effectively explore the capability of the GPS representation, we propose a novel human parsing-based gait recognition framework, named ParsingGait. ParsingGait contains a Convolutional Neural Network (CNN)-based backbone and two light-weighted heads. The first head extracts global semantic features from GPSs, while the other one learns mutual information of part-level features through Graph Convolutional Networks to model the detailed dynamics of human walking. Furthermore, due to the lack of suitable datasets, we build the first parsing-based dataset for gait recognition in the wild, named Gait3D-Parsing, by extending the large-scale and challenging Gait3D dataset. Based on Gait3D-Parsing, we comprehensively evaluate our method and existing gait recognition methods. Specifically, ParsingGait achieves a 17.5% Rank-1 increase compared with the state-of-the-art silhouette-based method. In addition, by replacing silhouettes with GPSs, current gait recognition methods achieve about 12.5% ~ 19.2% improvements in Rank-1 accuracy. The experimental results show a significant improvement in accuracy brought by the GPS representation and the superiority of ParsingGait.