Weakly Supervised Object Localization (WSOL) aims to localize objects using only image-level labels while ensuring competitive classification performance. However, previous efforts have prioritized localization over classification accuracy in discriminative features, in which low-level information is neglected. We argue that low-level image representations, such as edges, color, texture, and motions are crucial for accurate detection. That is, using such information further achieves more refined localization, which can be used to promote classification accuracy. In this paper, we propose a unified framework that simultaneously improves localization and classification accuracy, termed as LocLoc (Low-level Cues and Local-area Guides). It leverages low-level image cues to explore global and local representations for accurate localization and classification. Specifically, we introduce a GrabCut-Enhanced Generator (GEG) to learn global semantic representations for localization based on graph cuts to enhance low-level information based on long-range dependencies captured by the transformer. We further design a Local Feature Digging Module (LFDM) that utilizes low-level cues to guide the learning route of local feature representations for accurate classification. Extensive experiments demonstrate the effectiveness of LocLoc with 84.4%(↑5.2%) Top-1 Loc., 85.8% Top-1 Cls. on CUB-200-2011 and 57.6% (↑1.5%) Top-1 Loc., 78.6% Top-1Cls. on ILSVRC 2012, indicating that our method achieves competitive performance with a large margin compared to previous approaches. Code and models are available at https://github.com/Cliffia123/LocLoc.
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Semi-supervised Domain Adaptation (SSDA) aims to learn a well-performed model using fully labeled source samples and scarcely labeled target samples, along with unlabeled target samples. Due to the dominant presence of labeled samples from the source domain in the training data, both the feature extractor and classifier can display bias towards the source domain. This can result in sub-optimal feature extraction for the challenging target samples that have notable differences from the source domain. Moreover, the source-favored classifier can hinder the classification performance of the target domain. To this end, we propose a novel Joint Contrastive Learning with Sensitivity (JCLS) in this paper, which consists of sensitivity-aware feature contrastive learning (SFCL) and class-wise probabilistic contrastive learning (CPCL). Different from the traditional contrastive learning, SFCL pays more attention to the sensitive samples during optimizing the feature extractor, and consequently the feature discrimination of unlabeled samples can be enhanced. CPCL performs class-wise contrastive learning in the probabilistic space to enforce the cross-domain classifier to match the real distribution of source and target samples. By combining these two components, our JCLS is able to extract domain-invariant and compact features and obtain a well-performed classifier. We conduct the experiments on the DomainNet and Office-Home benchmarks, and the results show that our approach achieves state-of-the-art performance.
Visual Commonsense Reasoning (VCR) calls for explanatory reasoning behind question answering over visual scenes. To achieve this goal, a model is required to provide an acceptable rationale as the reason for the predicted answers. Progress on the benchmark dataset stems largely from the recent advancement of Vision-Language Transformers (VL Transformers). These models are first pre-trained on some generic large-scale vision-text datasets, and then the learned representations are transferred to the downstream VCR task. Despite their attractive performance, this paper posits that the VL Transformers do not exhibit visual commonsense, which is the key to VCR. In particular, our empirical results pinpoint several shortcomings of existing VL Transformers: small gains from pre-training, unexpected language bias, limited model architecture for the two inseparable sub-tasks, and neglect of the important object-tag correlation. With these findings, we tentatively suggest some future directions from the aspect of dataset, evaluation metric, and training tricks. We believe this work could make researchers revisit the intuition and goals of VCR, and thus help tackle the remaining challenges in visual reasoning.
Incorporating large image-text foundation models such as CLIP has substantially improved the performance of the multimodal video retrieval task. However, how to practically sample the frames from a video and aggregate the frame features into a video representation is still an open research question. In particular, real-world deployment scenarios, such as embodiment within consumer electronics or cloud-based inference pipelines, require two key facets of retrieval (representation building and search) to be computationally light and fast. In this paper, we propose AdaCLIP, a computation- and latency-aware system for pragmatic multimodal video retrieval. AdaCLIP consists of a learning-based frame selection module to select informative frames and a query-independent frame aggregation module to obtain strong video representations from the frame features. Specifically, in the frame selection module, we introduce a differentiable Hard-Top-k algorithm to sample a subset of the frames while optimizing the performance of the video retrieval task in an end-to-end manner. Moreover, to be latency-aware, we also propose a query-independent lightweight approach, MLP-Score, to aggregate the frame features into the video representation, which offers up to 142x speedup on GPU and 822x speedup on CPU in similarity search time compared to query-dependent matching methods. Experimental results on several popular video retrieval datasets confirm the effectiveness of AdaCLIP.
Model Inversion (MI) attacks aim to recover the private training data from the target model, which has raised security concerns about the deployment of DNNs in practice. Recent advances in generative adversarial models have rendered them particularly effective in MI attacks, primarily due to their ability to generate high-fidelity and perceptually realistic images that closely resemble the target data. In this work, we propose a novel Dynamic Memory Model Inversion Attack (DMMIA) to leverage historically learned knowledge, which interacts with samples (during the training) to induce diverse generations. DMMIA constructs two types of prototypes to inject the information about historically learned knowledge: Intra-class Multicentric Representation (IMR) representing target-related concepts by multiple learnable prototypes, and Inter-class Discriminative Representation (IDR) characterizing the memorized samples as learned prototypes to capture more privacy-related information. As a result, our DMMIA has a more informative representation, which brings more diverse and discriminative generated results. Experiments on multiple benchmarks show that DMMIA performs better than state-of-the-art MI attack methods.
Although the attention mechanism in transformers has proven successful in image-text retrieval tasks, most transformer models suffer from a large number of parameters. Inspired by brain circuits that process information with recurrent connected neurons, we propose a novel Reservoir Computing Transformer Reasoning Network (RCTRN) for image-text retrieval. The proposed RCTRN employs a two-step strategy to focus on feature representation and data distribution of different modalities respectively. Specifically, we send visual and textual features through a unified meshed reasoning module, which encodes multi-level feature relationships with prior knowledge and aggregates the complementary outputs in a more effective way. The reservoir reasoning network is proposed to optimize memory connections between features at different stages and address the data distribution mismatch problem introduced by the unified scheme. To investigate the significance of the low power dissipation and low bandwidth characteristics of RRN in practical scenarios, we deployed the model in the wireless transmission system, demonstrating that RRN's optimization of data structures also has a certain robustness against channel noise. Extensive experiments on two benchmark datasets, Flickr30K and MS-COCO, demonstrate the superiority of RCTRN in terms of performance and low-power dissipation compared to state-of-the-art baselines.
Hierarchical Prompt Learning Using CLIP for Multi-label Classification with Single Positive Labels
PDF ↗Collecting full annotations to construct multi-label datasets is difficult and labor-consuming. As an effective solution to relieve the annotation burden, single positive multi-label learning (SPML) draws increasing attention from both academia and industry. It only annotates each image with one positive label, leaving other labels unobserved. Therefore, existing methods strive to explore the cue of unobserved labels to compensate for the insufficiency of label supervision. Though achieving promising performance, they generally consider labels independently, leaving out the inherent hierarchical semantic relationship among labels which reveals that labels can be clustered into groups. In this paper, we propose a hierarchical prompt learning method with a novel Hierarchical Semantic Prompt Network (HSPNet) to harness such hierarchical semantic relationships using a large-scale pretrained vision and language model, i.e., CLIP, for SPML. We first introduce a Hierarchical Conditional Prompt (HCP) strategy to grasp the hierarchical label-group dependency. Then we equip a Hierarchical Graph Convolutional Network (HGCN) to capture the high-order inter-label and inter-group dependencies. Comprehensive experiments and analyses on several benchmark datasets show that our method significantly outperforms the state-of-the-art methods, well demonstrating its superiority and effectiveness. Our code will be available at https://github.com/jameslahm/HSPNet.
Recently supervised contrastive learning (SCL) has achieved remarkable progress in semantic segmentation. Nevertheless, prior works have often necessitated a substantial number of samples to attain satisfactory performance, leading to a significant increase in training overhead. In this work, we leverage the idea of reweighting each pair to reduce the demand for large numbers of training samples in contrastive learning and propose a novel loss, dubbed confidence-aware contrastive (CAC) loss, which adaptively reweights each pair according to the predicted confidence for semantic segmentation. To alleviate the misalignment between supervised learning and contrastive learning, we further introduce an extra weight branch with a stop-gradient operator to generate the pair weights. Moreover, we present a confidence-aware marginal anchor sampling method for the calculation of supervised contrastive loss which focuses on marginal rather than the hardest pairs. Coupling with our method consistently improves the performance of various models (e.g. HRNet, OCRNet, SegFormer) on Cityscapes, ADE20K, PASCAL-Context, and COCO-Stuff datasets. Compared to existing SCL-based methods, the proposed method achieves competitive or even better results without relying on a memory bank or a large number of samples. Our code is at https://github.com/CVIU-CSU/Confidence-Aware-Contrastive-Loss.
Class Activation Map (CAM) has emerged as a popular tool for weakly supervised semantic segmentation (WSSS), allowing the localization of object regions in an image using only image-level labels. However, existing CAM methods suffer from under-activation of target object regions and false-activation of background regions due to the fact that a lack of detailed supervision can hinder the model's ability to understand the image as a whole. In this paper, we propose a novel Question-Answer Cross-Language-Image Matching framework for WSSS (QA-CLIMS), leveraging the vision-language foundation model to maximize the text-based understanding of images and guide the generation of activation maps. First, a series of carefully designed questions are posed to the VQA (Visual Question Answering) model with Question-Answer Prompt Engineering (QAPE) to generate a corpus of both foreground target objects and backgrounds that are adaptive to query images. We then employ contrastive learning in a Region Image Text Contrastive (RITC) network to compare the obtained foreground and background regions with the generated corpus. Our approach exploits the rich textual information from the open vocabulary as additional supervision, enabling the model to generate high-quality CAMs with a more complete object region and reduce false-activation of background regions. We conduct extensive analysis to validate the proposed method and show that our approach performs state-of-the-art on both PASCAL VOC 2012 and MS COCO datasets.
Visual Entailment (VE) is a fine-grained reasoning task aiming to predict whether the image semantically entails a hypothesis in textual form.Existing studies of VE only focus on basic visual attributes but largely overlook the importance of scene text, which usually entails rich semantic information and crucial clues (e.g., time, place, affiliation, and topic), leading to superficial design of hypothesis or incorrect entailment prediction. To fill this gap, we propose a new task called scene-text oriented Visual Entailment (STOVE), which requires models to predict whether an image semantically entails the corresponding hypothesis designed based on the scene text-centered visual information.STOVE task challenges a model to deeply understand the interplay between language and images containing scene text, requiring aligning hypotheses tokens, scene text, and visual contents.To support the researches on STOVE, we further collect a dataset termed TextVE, consisting of 23,864 images and 47,728 hypotheses related to scene text, which is constructed with the strategy of minimizing biases.Additionally, we present a baseline named MMTVE applying a multimodal transformer to model the spatial, semantic, and visual reasoning relations between multiple scene text tokens, hypotheses, and visual features.Experimental results illustrate that our model is effective in comprehending STOVE and achieves outstanding performance.Our codes are available at https://github.com/VISLANG-Lab/TextVE.
Current mainstream vision-language (VL) tracking framework consists of three parts,i.e., a visual feature extractor, a language feature extractor, and a fusion model. To pursue better performance, a natural modus operandi for VL tracking is employing customized and heavier unimodal encoders, and multi-modal fusion models. Albeit effective, existing VL trackers separate feature extraction and feature integration, resulting in extracted features that lack semantic guidance and have limited target-aware capability in complex scenarios, e.g., similar distractors and extreme illumination. In this work, inspired by the recent success of exploring foundation models with unified architecture for both natural language and computer vision tasks, we propose an All-in-One framework, which learns joint feature extraction and interaction by adopting a unified transformer backbone. Specifically, we mix raw vision and language signals to generate language-injected vision tokens, which we then concatenate before feeding into the unified backbone architecture. This approach achieves feature integration in a unified backbone, removing the need for carefully-designed fusion modules and resulting in a more effective and efficient VL tracking framework. To further improve the learning efficiency, we introduce a multi-modal alignment module based on cross-modal and intra-modal contrastive objectives, providing more reasonable representations for the unified All-in-One transformer backbone. Extensive experiments on five benchmarks, i.e., OTB99-L, TNL2K, LaSOT, LaSOTExt and WebUAV-3M, demonstrate the superiority of the proposed tracker against existing state-of-the-art (SOTA) methods on VL tracking. Codes will be available at https://github.com/983632847/All-in-One here.
PoSynDA: Multi-Hypothesis Pose Synthesis Domain Adaptation for Robust 3D Human Pose Estimation
PDF ↗The current 3D human pose estimators face challenges in adapting to new datasets due to the scarcity of 2D-3D pose pairs in target domain training sets. We present the Multi-Hypothesis Pose Synthesis Domain Adaptation (PoSynDA) framework to overcome this issue without extensive target domain annotation. Utilizing a diffusion-centric structure, PoSynDA simulates the 3D pose distribution in the target domain, filling the data diversity gap. By incorporating a multi-hypothesis network, it creates diverse pose hypotheses and aligns them with the target domain. Target-specific source augmentation obtains the target domain distribution data from the source domain by decoupling the scale and position parameters. The teacher-student paradigm and low-rank adaptation further refine the process. PoSynDA demonstrates competitive performance on benchmarks, such as Human3.6M, MPI-INF-3DHP, and 3DPW, even comparable with the target-trained MixSTE model. This work paves the way for the practical application of 3D human pose estimation1. The source code is available at https://github.com/hbing-l/PoSynDA.
Unsupervised salient object detection aims to detect salient objects without using supervision signals eliminating the tedious task of manually labeling salient objects. To improve training efficiency, end-to-end methods for USOD have been proposed as a promising alternative. However, current solutions rely heavily on noisy handcraft labels and fail to mine rich semantic information from deep features. In this paper, we propose a self-supervised end-to-end salient object detection framework via top-down context. Specifically, motivated by contrastive learning, we exploit the self-localization from the deepest feature to construct the location maps which are then leveraged to learn the most instructive segmentation guidance. Further considering the lack of detailed information in deepest features, we exploit the detail-boosting refiner module to enrich the location labels with details. Moreover, we observe that due to lack of supervision, current unsupervised saliency models tend to detect non-salient objects that are salient in some other samples of corresponding scenarios. To address this widespread issue, we design a novel Unsupervised Non-Salient Suppression (UNSS) method developing the ability to ignore non-salient objects. Extensive experiments on benchmark datasets demonstrate that our method achieves leading performance among the recent end-to-end methods and most of the multi-stage solutions. The code is available.
In this paper, we introduce a novel approach to address the task of synthesizing speech from silent videos of any in-the-wild speaker solely based on lip movements. The traditional approach of directly generating speech from lip videos faces the challenge of not being able to learn a robust language model from speech alone, resulting in unsatisfactory outcomes. To overcome this issue, we propose incorporating noisy text supervision using a state-of-the-art lip-to-text network that instills language information into our model. The noisy text is generated using a pre-trained lip-to-text model, enabling our approach to work without text annotations during inference. We design a visual text-to-speech network that utilizes the visual stream to generate accurate speech, which is in-sync with the silent input video. We perform extensive experiments and ablation studies, demonstrating our approach's superiority over the current state-of-the-art methods on various benchmark datasets. Further, we demonstrate an essential practical application of our method in assistive technology by generating speech for an ALS patient who has lost the voice but can make mouth movements. Our demo video, code, and additional details can be found at http://cvit.iiit.ac.in/research/projects/cvit-projects/ms-l2s-itw.
Image aesthetic assessment (IAA) has drawn wide attention in recent years as more and more users post images and texts on the Internet to share their views. The intense subjectivity and complexity of IAA make it extremely challenging. Text triggers the subjective expression of human aesthetic experience based on human implicit memory, so incorporating the textual information and identifying the relationship with the image is of great importance for IAA. However, IAA with the image as input fails to fully consider subjectivity, while existing multimodal IAA ignores the interrelationship among modalities. To this end, we propose a brain-inspired multimodal interaction network (BMI-Net) that simulates how the association area of the cerebral cortex processes sensory stimuli. In particular, the knowledge integration LSTM (KI-LSTM) is proposed to learn the image-text interaction relation. The proposed scalable multimodal fusion (SMF) based on low-rank decomposition fuses image, text and interaction modalities to predict the aesthetic distribution. Extensive experiments show that the proposed BMI-Net outperforms existing state-of-the-art methods on three IAA tasks.
Contemporary news reporting increasingly features multimedia content, motivating research on multimedia event extraction. However, the task lacks annotated multimodal training data and artificially generated training data suffer from the distribution shift from the real-world data. In this paper, we propose Cross-modality Augmented Multimedia Event Learning (CAMEL), which successfully utilizes artificially generated multimodal training data and achieves state-of-the-art performance. Conditioned on unimodal training data, we generate multimodal training data using off-the-shelf image generators like Stable Diffusion [45] and image captioners like BLIP [24]. After that, we train the network on the resultant multimodal datasets. In order to learn robust features that are effective across domains, we devise an iterative and gradual training strategy. Substantial experiments show that CAMEL surpasses state-of-the-art (SOTA) baselines on the M2E2 benchmark. On multimedia events in particular, we outperform the prior SOTA by 4.2% F1 on event mention identification and by 9.8% F1 on argument identification, which demonstrates that CAMEL learns synergistic representations from the two modalities. Our work demonstrates a recipe to unleash the power of synthetic training data in structured prediction.
Spectral modeling plays a critical role in denoising hyperspectral images (HSIs), with recent approaches leveraging well-designed network architectures to extract spectral contexts for noise removal. However, these approaches overlook a striking finding: the presence of spectral differences in noisy contexts can pose challenges for the denoising network during the restoration process of each band in the HSI. We attribute this to the varying levels of spectral difference between different bands and the unknown distribution of various noises. These factors can make it difficult for the network to capture consistent features, ultimately leading to suboptimal solutions. We propose a novel concept termed 'spectral displacement,' which views spectral differences as pixel motion displacement along the spectral domain. To eliminate the effect of spectral displacement, we introduce a potential solution: spectral alignment. This approach can increase the mutual information between different spectral bands and enhance the effectiveness of denoising. We then present the Spectral Alignment Recurrent Network (SARN) for efficient and effective displacement estimation and pixel-level alignment between neighboring bands. SARN can serve as a general plug-in for HSI backbones without requiring any model-specific design. Experimental results on several benchmark datasets confirm the effectiveness and superiority of our concept and network. The source code will be available at https://github.com/MIV-XJTU/SARN.
Weakly supervised object localization (WSOL) is one of the most popular and challenging tasks in computer vision. This task is to localize the objects in the images given only the image-level supervision. Recently, dividing WSOL into two parts (class-agnostic object localization and object classification) has become the state-of-the-art pipeline for this task. However, existing solutions under this pipeline usually suffer from the following drawbacks: 1) they are not flexible since they can only localize one object for each image due to the adopted single-class regression (SCR) for localization; 2) the generated pseudo bounding boxes may be noisy, but the negative impact of such noise is not well addressed. To remedy these drawbacks, we first propose to replace SCR with a binary-class detector (BCD) for localizing multiple objects, where the detector is trained by discriminating the foreground and background. Then we design a weighted entropy (WE) loss using the unlabeled data to reduce the negative impact of noisy bounding boxes. Extensive experiments on the popular CUB-200-2011 and ImageNet-1K datasets demonstrate the effectiveness of our method.
Video action segmentation aims to densely cast each video frame into a set of pre-defined human action categories. This work proposes a novel model, dubbed as diffused Fourier network (DFN) for video action segmentation. It advances the research frontier by addressing several central bottlenecks in the existing methods for video action segmentation. First, capturing long-range dependence among video frames is known to be crucial for precisely estimating the temporal boundaries for actions. Rather than relying on compute-intensive self-attention modules or stacking multi-rate dilated convolutions as in previous models (e.g., ASFormer), we devise Fourier token mixer over shiftable temporal windows in the video sequence, which harnesses the parameter-free and light-weighted Fast Fourier Transform (FFT) for efficient spectral-temporal feature learning. Essentially, even simple spectral operations (e.g., pointwise product) bring global receptive field across the entire temporal window. The proposed Fourier token mixer thus provides a low-cost alternative for existing practice. Secondly, the results of action segmentation tend to be fragmented, primarily due to the noisy per-frame action likelihood, known as over-segmentation in the literature. Inspired by the recently-proposed diffusion models, we treat over-segments as noises corrupting the true temporal boundaries, and conduct denoising via a recurrent execution of a parameter-sharing module, akin to the backward denoising process in the diffusion models. Comprehensive experiments on three video benchmarks (GTEA, 50salads and Breakfast) have clearly validated that the proposed method can strike an excellent balance between computations / parameter count and accuracy.
ZRIGF: An Innovative Multimodal Framework for Zero-Resource Image-Grounded Dialogue Generation
PDF ↗Image-grounded dialogue systems benefit greatly from integrating visual information, resulting in high-quality response generation. However, current models struggle to effectively utilize such information in zero-resource scenarios, mainly due to the disparity between image and text modalities. To overcome this challenge, we propose an innovative multimodal framework, called ZRIGF, which assimilates image-grounded information for dialogue generation in zero-resource situations. ZRIGF implements a two-stage learning strategy, comprising contrastive pre-training and generative pre-training. Contrastive pre-training includes a text-image matching module that maps images and texts into a unified encoded vector space, along with a text-assisted masked image modeling module that preserves pre-training visual features and fosters further multimodal feature alignment. Generative pre-training employs a multimodal fusion module and an information transfer module to produce insightful responses based on harmonized multimodal representations. Comprehensive experiments conducted on both text-based and image-grounded dialogue datasets demonstrate ZRIGF's efficacy in generating contextually pertinent and informative responses. Furthermore, we adopt a fully zero-resource scenario in the image-grounded dialogue dataset to demonstrate our framework's robust generalization capabilities in novel domains.