With the rapid growth in deepfake video content we require improved and generalizable methods to detect them. Most existing detection methods either use uni-modal cues or rely on supervised training to capture the dissonance between the audio and visual modalities. While the former disregards the audio-visual correspondences entirely the latter predominantly focuses on discerning audio-visual cues within the training corpus thereby potentially overlooking correspondences that can help detect unseen deepfakes. We present Audio-Visual Feature Fusion (AVFF) a two-stage cross-modal learning method that explicitly captures the correspondence between the audio and visual modalities for improved deepfake detection. The first stage pursues representation learning via self-supervision on real videos to capture the intrinsic audio-visual correspondences. To extract rich cross-modal representations we use contrastive learning and autoencoding objectives and introduce a novel audio-visual complementary masking and feature fusion strategy. The learned representations are tuned in the second stage where deepfake classification is pursued via supervised learning on both real and fake videos. Extensive experiments and analysis suggest that our novel representation learning paradigm is highly discriminative in nature. We report 98.6% accuracy and 99.1% AUC on the FakeAVCeleb dataset outperforming the current audio-visual state-of-the-art by 14.9% and 9.9% respectively.
论文检索
输入标题、作者或关键词，从 7,876 篇学术成果中精准定位
In-distribution Public Data Synthesis with Diffusion Models for Differentially Private Image Classification
PDF ↗To alleviate the utility degradation of deep learning image classification with differential privacy (DP) employing extra public data or pre-trained models has been widely explored. Recently the use of in-distribution public data has been investigated where tiny subsets of datasets are released publicly. In this paper we investigate a framework that leverages recent diffusion models to amplify the information of public data. Subsequently we identify data diversity and generalization gap between public and private data as critical factors addressing the limited public data. While assuming 4% of training data as public our method achieves 85.48% on CIFAR-10 with a privacy budget of ?=2 without employing extra public data for training.
Text-to-image (T2I) generative models have recently emerged as a powerful tool enabling the creation of photo-realistic images and giving rise to a multitude of applications. However the effective integration of T2I models into fundamental image classification tasks remains an open question. A prevalent strategy to bolster image classification performance is through augmenting the training set with synthetic images generated by T2I models. In this study we scrutinize the shortcomings of both current generative and conventional data augmentation techniques. Our analysis reveals that these methods struggle to produce images that are both faithful (in terms of foreground objects) and diverse (in terms of background contexts) for domain-specific concepts. To tackle this challenge we introduce an innovative inter-class data augmentation method known as Diff-Mix (\href https://github.com/Zhicaiwww/Diff-Mix) https://github.com/Zhicaiwww/Diff-Mix which enriches the dataset by performing image translations between classes. Our empirical results demonstrate that Diff-Mix achieves a better balance between faithfulness and diversity leading to a marked improvement in performance across diverse image classification scenarios including few-shot conventional and long-tail classifications for domain-specific datasets.
Backdoor attack poses a significant security threat to Deep Learning applications. Existing attacks are often not evasive to established backdoor detection techniques. This susceptibility primarily stems from the fact that these attacks typically leverage a universal trigger pattern or transformation function such that the trigger can cause misclassification for any input. In response to this recent papers have introduced attacks using sample-specific invisible triggers crafted through special transformation functions. While these approaches manage to evade detection to some extent they reveal vulnerability to existing backdoor mitigation techniques. To address and enhance both evasiveness and resilience we introduce a novel backdoor attack LOTUS. Specifically it leverages a secret function to separate samples in the victim class into a set of partitions and applies unique triggers to different partitions. Furthermore LOTUS incorporates an effective trigger focusing mechanism ensuring only the trigger corresponding to the partition can induce the backdoor behavior. Extensive experimental results show that LOTUS can achieve high attack success rate across 4 datasets and 7 model structures and effectively evading 13 backdoor detection and mitigation techniques. The code is available at https://github.com/Megum1/LOTUS.
Modeling Collaborator: Enabling Subjective Vision Classification With Minimal Human Effort via LLM Tool-Use
PDF ↗From content moderation to wildlife conservation the number of applications that require models to recognize nuanced or subjective visual concepts is growing. Traditionally developing classifiers for such concepts requires substantial manual effort measured in hours days or even months to identify and annotate data needed for training. Even with recently proposed Agile Modeling techniques which enable rapid bootstrapping of image classifiers users are still required to spend 30 minutes or more of monotonous repetitive data labeling just to train a single classifier. Drawing on Fiske's Cognitive Miser theory we propose a new framework that alleviates manual effort by replacing human labeling with natural language interactions reducing the total effort required to define a concept by an order of magnitude: from labeling 2000 images to only 100 plus some natural language interactions. Our framework leverages recent advances in foundation models both large language models and vision-language models to carve out the concept space through conversation and by automatically labeling training data points. Most importantly our framework eliminates the need for crowd-sourced annotations. Moreover our framework ultimately produces lightweight classification models that are deployable in cost-sensitive scenarios. Across 15 subjective concepts and across 2 public image classification datasets our trained models outperform traditional Agile Modeling as well as state-of-the-art zero-shot classification models like ALIGN CLIP CuPL and large visual question answering models like PaLI-X.
Large language models (LLMs) are fine-tuned using human comparison data with Reinforcement Learning from Human Feedback (RLHF) methods to make them better aligned with users' preferences. In contrast to LLMs human preference learning has not been widely explored in text-to-image diffusion models; the best existing approach is to fine-tune a pretrained model using carefully curated high quality images and captions to improve visual appeal and text alignment. We propose Diffusion-DPO a method to align diffusion models to human preferences by directly optimizing on human comparison data. Diffusion-DPO is adapted from the recently developed Direct Preference Optimization (DPO) a simpler alternative to RLHF which directly optimizes a policy that best satisfies human preferences under a classification objective. We re-formulate DPO to account for a diffusion model notion of likelihood utilizing the evidence lower bound to derive a differentiable objective. Using the Pick-a-pic dataset of 851K crowdsourced pairwise preferences we fine-tune the base model of the state-of-the-art Stable Diffusion XL (SDXL)-1.0 model with Diffusion-DPO. Our fine-tuned base model significantly outperforms both base SDXL-1.0 and the larger SDXL-1.0 model consisting of an additional refinement model in human evaluation improving visual appeal and prompt alignment. We also develop a variant that uses AI feedback and has comparable performance to training on human preferences opening the door for scaling of diffusion model alignment methods.
The pretraining-finetuning paradigm has gained popularity in various computer vision tasks. In this paradigm the emergence of active finetuning arises due to the abundance of large-scale data and costly annotation requirements. Active finetuning involves selecting a subset of data from an unlabeled pool for annotation facilitating subsequent finetuning. However the use of a limited number of training samples can lead to a biased distribution potentially resulting in model overfitting. In this paper we propose a new method called ActiveDC for the active finetuning tasks. Firstly we select samples for annotation by optimizing the distribution similarity between the subset to be selected and the entire unlabeled pool in continuous space. Secondly we calibrate the distribution of the selected samples by exploiting implicit category information in the unlabeled pool. The feature visualization provides an intuitive sense of the effectiveness of our approach to distribution calibration. We conducted extensive experiments on three image classification datasets with different sampling ratios. The results indicate that ActiveDC consistently outperforms the baseline performance in all image classification tasks. The improvement is particularly significant when the sampling ratio is low with performance gains of up to 10%. Our code will be released.
Multiple camera view (multi-view) setups have proven useful in many computer vision applications. However the high computational cost associated with multiple views creates a significant challenge for end devices with limited computational resources. In modern CPU pipelining breaks a longer job into steps and enables parallelism over sequential steps from multiple jobs. Inspired by this we study selective view pipelining for efficient multi-view understanding which breaks computation of multiple views into steps and only computes the most helpful views/steps in a parallel manner for the best efficiency. To this end we use reinforcement learning to learn a very light view selection module that analyzes the target object or scenario from initial views and selects the next-best-view for recognition or detection for pipeline computation. Experimental results on multi-view classification and detection tasks show that our approach achieves promising performance while using only 2 or 3 out of N available views significantly reducing computational costs while maintaining parallelism over GPU through selective view pipelining.
With the emergence of pre-trained vision-language models like CLIP how to adapt them to various downstream classification tasks has garnered significant attention in recent research. The adaptation strategies can be typically categorized into three paradigms: zero-shot adaptation few-shot adaptation and the recently-proposed training-free few-shot adaptation. Most existing approaches are tailored for a specific setting and can only cater to one or two of these paradigms. In this paper we introduce a versatile adaptation approach that can effectively work under all three settings. Specifically we propose the dual memory networks that comprise dynamic and static memory components. The static memory caches training data knowledge enabling training-free few-shot adaptation while the dynamic memory preserves historical test features online during the testing process allowing for the exploration of additional data insights beyond the training set. This novel capability enhances model performance in the few-shot setting and enables model usability in the absence of training data. The two memory networks employ the same flexible memory interactive strategy which can operate in a training-free mode and can be further enhanced by incorporating learnable projection layers. Our approach is tested across 11 datasets under the three task settings. Remarkably in the zero-shot scenario it outperforms existing methods by over 3% and even shows superior results against methods utilizing external training data. Additionally our method exhibits robust performance against natural distribution shifts.
Protein representation learning is a challenging task that aims to capture the structure and function of proteins from their amino acid sequences. Previous methods largely ignored the fact that not all amino acids are equally important for protein folding and activity. In this article we propose a neural clustering framework that can automatically discover the critical components of a protein by considering both its primary and tertiary structure information. Our framework treats a protein as a graph where each node represents an amino acid and each edge represents a spatial or sequential connection between amino acids. We then apply an iterative clustering strategy to group the nodes into clusters based on their 1D and 3D positions and assign scores to each cluster. We select the highest-scoring clusters and use their medoid nodes for the next iteration of clustering until we obtain a hierarchical and informative representation of the protein. We evaluate on four protein-related tasks: protein fold classification enzyme reaction classification gene ontology term prediction and enzyme commission number prediction. Experimental results demonstrate that our method achieves state-of-the-art performance.
With the growing size of pre-trained models full fine-tuning and storing all the parameters for various downstream tasks is costly and infeasible. In this paper we propose a new parameter-efficient fine-tuning method Gradient-based Parameter Selection (GPS) demonstrating that only tuning a few selected parameters from the pre-trained model while keeping the remainder of the model frozen can generate similar or better performance compared with the full model fine-tuning method. Different from the existing popular and state-of-the-art parameter-efficient fine-tuning approaches our method does not introduce any additional parameters and computational costs during both the training and inference stages. Another advantage is the model-agnostic and non-destructive property which eliminates the need for any other design specific to a particular model. Compared with the full fine-tuning GPS achieves 3.33% (91.78% vs. 88.45% FGVC) and 9.61% (73.1% vs. 65.57% VTAB) improvement of the accuracy with tuning only 0.36% parameters of the pre-trained model on average over 24 image classification tasks; it also demonstrates a significant improvement of 17% and 16.8% in mDice and mIoU respectively on medical image segmentation task. Moreover GPS achieves state-of-the-art performance compared with existing PEFT methods. The code will be available in https://github.com/FightingFighting/GPS.git.
Simulation is an invaluable tool for radio-frequency system designers that enables rapid prototyping of various algorithms for imaging target detection classification and tracking. However simulating realistic radar scans is a challenging task that requires an accurate model of the scene radio frequency material properties and a corresponding radar synthesis function. Rather than specifying these models explicitly we propose DART - Doppler Aided Radar Tomography a Neural Radiance Field-inspired method which uses radar-specific physics to create a reflectance and transmittance-based rendering pipeline for range-Doppler images. We then evaluate DART by constructing a custom data collection platform and collecting a novel radar dataset together with accurate position and instantaneous velocity measurements from lidar-based localization. In comparison to state-of-the-art baselines DART synthesizes superior radar range-Doppler images from novel views across all datasets and additionally can be used to generate high quality tomographic images.
To build a cross-modal latent space between 3D human motion and language acquiring large-scale and high-quality human motion data is crucial. However unlike the abundance of image data the scarcity of motion data has limited the performance of existing motion-language models. To counter this we introduce "motion patches" a new representation of motion sequences and propose using Vision Transformers (ViT) as motion encoders via transfer learning aiming to extract useful knowledge from the image domain and apply it to the motion domain. These motion patches created by dividing and sorting skeleton joints based on body parts in motion sequences are robust to varying skeleton structures and can be regarded as color image patches in ViT. We find that transfer learning with pre-trained weights of ViT obtained through training with 2D image data can boost the performance of motion analysis presenting a promising direction for addressing the issue of limited motion data. Our extensive experiments show that the proposed motion patches used jointly with ViT achieve state-of-the-art performance in the benchmarks of text-to-motion retrieval and other novel challenging tasks such as cross-skeleton recognition zero-shot motion classification and human interaction recognition which are currently impeded by the lack of data.
Vision-Language Models (VLMs) have demonstrated impressive performance on zero-shot classification i.e. classification when provided merely with a list of class names. In this paper we tackle the case of zero-shot classification in the presence of unlabeled data. We leverage the graph structure of the unlabeled data and introduce ZLaP a method based on label propagation (LP) that utilizes geodesic distances for classification. We tailor LP to graphs containing both text and image features and further propose an efficient method for performing inductive inference based on a dual solution and a sparsification step. We perform extensive experiments to evaluate the effectiveness of our method on 14 common datasets and show that ZLaP outperforms the latest related works. Code: https://github.com/vladan-stojnic/ZLaP
Parameter-efficient fine-tuning (PEFT) is an effective methodology to unleash the potential of large foundation models in novel scenarios with limited training data. In the computer vision community PEFT has shown effectiveness in image classification but little research has studied its ability for image segmentation. Fine-tuning segmentation models usually require a heavier adjustment of parameters to align the proper projection directions in the parameter space for new scenarios. This raises a challenge to existing PEFT algorithms as they often inject a limited number of individual parameters into each block which prevents substantial adjustment of the projection direction of the parameter space due to the limitation of Hidden Markov Chain along blocks. In this paper we equip PEFT with a cross-block orchestration mechanism to enable the adaptation of the Segment Anything Model (SAM) to various downstream scenarios. We introduce a novel inter-block communication module which integrates a learnable relation matrix to facilitate communication among different coefficient sets of each PEFT block's parameter space. Moreover we propose an intra-block enhancement module which introduces a linear projection head whose weights are generated from a hyper-complex layer further enhancing the impact of the adjustment of projection directions on the entire parameter space. Extensive experiments on diverse benchmarks demonstrate that our proposed approach consistently improves the segmentation performance significantly on novel scenarios with only around 1K additional parameters.
Recent advances in unsupervised learning have demonstrated the ability of large vision models to achieve promising results on downstream tasks by pre-training on large amount of unlabelled data. Such pre-training techniques have also been explored recently in the remote sensing domain due to the availability of large amount of unlabelled data. Different from standard natural image datasets remote sensing data is acquired from various sensor technologies and exhibit diverse range of scale variations as well as modalities. Existing satellite image pre-training methods either ignore the scale information present in the remote sensing imagery or restrict themselves to use only a single type of data modality. In this paper we re-visit transformers pre-training and leverage multi-scale information that is effectively utilized with multiple modalities. Our proposed approach named SatMAE++ performs multi-scale pre-training and utilizes convolution based upsampling blocks to reconstruct the image at higher scales making it extensible to include more scales. Compared to existing works the proposed SatMAE++ with multi-scale pre-training is equally effective for both optical as well as multi-spectral imagery. Extensive experiments on six datasets reveal the merits of proposed contributions leading to state-of-the-art performance on all datasets. SatMAE++ achieves mean average precision (mAP) gain of 2.5% for multi-label classification task on BigEarthNet dataset.
We introduce SODA a self-supervised diffusion model designed for representation learning. The model incorporates an image encoder which distills a source view into a compact representation that in turn guides the generation of related novel views. We show that by imposing a tight bottleneck between the encoder and a denoising decoder and leveraging novel view synthesis as a self-supervised objective we can turn diffusion models into strong representation learners capable of capturing visual semantics in an unsupervised manner. To the best of our knowledge SODA is the first diffusion model to succeed at ImageNet linear-probe classification and at the same time it accomplishes reconstruction editing and synthesis tasks across a wide range of datasets. Further investigation reveals the disentangled nature of its emergent latent space that serves as an effective interface to control and manipulate the produced images. All in all we aim to shed light on the exciting and promising potential of diffusion models not only for image generation but also for learning rich and robust representations. See our website at soda-diffusion.github.io.
Computer vision tasks typically involve describing what is visible in an image (e.g. classification detection segmentation and captioning). We study a visual common sense task that requires understanding 'what is not visible'. Specifically given an image (e.g. of a living room) and a name of an object ("cushion") a vision system is asked to predict semantically-meaningful regions (masks or bounding boxes) in the image where that object could be placed or is likely be placed by humans (e.g. on the sofa). We call this task: Semantic Placement (SP) and believe that such common-sense visual understanding is critical for assitive robots (tidying a house) AR devices (automatically rendering an object in the user's space) and visually-grounded chatbots with common sense. Studying the invisible is hard. Datasets for image description are typically constructed by curating relevant images (e.g. via image search with object names) and asking humans to annotate the contents of the image; neither of those two steps are straightforward for objects not present in the image. We overcome this challenge by operating in the opposite direction: we start with an image of an object in context (which is easy to find online) and remove that object from the image via inpainting. This automated pipeline converts unstructured web data into a paired with/without object dataset. With this proposed data generation pipeline we collect a novel dataset containing 1.3M images across 9 object categories. We then train a SP prediction model called CLIP-UNet on our dataset. The CLIP-UNet outperforms existing VLMs and baselines that combine semantic priors with object detectors generalizes well to real-world and simulated images exhibits semantics-aware reasoning for object placement and enables downstream applications like tidying robots in indoor environments.
Recent breakthroughs in vision-language models (VLMs) start a new page in the vision community. The VLMs provide stronger and more generalizable feature embeddings compared to those from ImageNet-pretrained models thanks to the training on the large-scale Internet image-text pairs. However despite the amazing achievement from the VLMs vanilla Vision Transformers (ViTs) remain the default choice for the image encoder. Although pure transformer proves its effectiveness in the text encoding area it remains questionable whether it is also the case for image encoding especially considering that various types of networks are proposed on the ImageNet benchmark which unfortunately are rarely studied in VLMs. Due to small data/model scale the original conclusions of model design on ImageNet can be limited and biased. In this paper we aim at building an evaluation protocol of vision models in the vision-language era under the contrastive language-image pretraining (CLIP) framework. We provide a comprehensive way to benchmark different vision models covering their zero-shot performance and scalability in both model and training data sizes. To this end we introduce ViTamin a new vision models tailored for VLMs. ViTamin-L significantly outperforms ViT-L by 2.0% ImageNet zero-shot accuracy when using the same publicly available DataComp-1B dataset and the same OpenCLIP training scheme. ViTamin-L presents promising results on 60 diverse benchmarks including classification retrieval open-vocabulary detection and segmentation and large multi-modal models. When further scaling up the model size our ViTamin-XL with only 436M parameters attains 82.9% ImageNet zero-shot accuracy surpassing 82.0% achieved by EVA-E that has ten times more parameters (4.4B).
Modeling and visualizing relationships between tasks or datasets is an important step towards solving various meta-tasks such as dataset discovery multi-tasking and transfer learning. However many relationships such as containment and transferability are naturally asymmetric and current approaches for representation and visualization (e.g. t-SNE) do not readily support this. We propose Task2Box an approach to represent tasks using box embeddings---axis-aligned hyperrectangles in low dimensional spaces---that can capture asymmetric relationships between them through volumetric overlaps. We show that Task2Box accurately predicts unseen hierarchical relationships between nodes in ImageNet and iNaturalist datasets as well as transferability between tasks in the Taskonomy benchmark. We also show that box embeddings estimated from task representations (e.g. CLIP Task2Vec or attribute based) can be used to predict relationships between unseen tasks more accurately than classifiers trained on the same representations as well as handcrafted asymmetric distances (e.g. KL divergence). This suggests that low-dimensional box embeddings can effectively capture these task relationships and have the added advantage of being interpretable. We use the approach to visualize relationships among publicly available image classification datasets on popular dataset hosting platform called Hugging Face.